AGREEMENT OF LIMITED PARTNERSHIP OF MARKWEST ENERGY PARTNERS, L.P.

SECOND AMENDED AND RESTATED

AGREEMENT OF LIMITED PARTNERSHIP

MARKWEST ENERGY PARTNERS, L.P.

TABLE OF CONTENTS

	ARTICLE I

	DEFINITIONS

Section 1.1	Definitions.	1
Section 1.2	Construction.	21

	ARTICLE II

	ORGANIZATION

Section 2.1	Formation.	21
Section 2.2	Name.	22
Section 2.3	Registered Office; Registered Agent; Principal Office; Other Offices.	22
Section 2.4	Purpose and Business.	22
Section 2.5	Powers.	23
Section 2.6	Power of Attorney.	23
Section 2.7	Term.	25
Section 2.8	Title to Partnership Assets.	25

	ARTICLE III

	RIGHTS OF LIMITED PARTNERS

Section 3.1	Limitation of Liability.	25
Section 3.2	Management of Business.	25
Section 3.3	Outside Activities of the Limited Partners.	26
Section 3.4	Rights of Limited Partners.	26

	ARTICLE IV

	CERTIFICATES; RECORD HOLDERS; TRANSFER OF PARTNERSHIP INTERESTS; REDEMPTION OF PARTNERSHIP INTERESTS

Section 4.1	Certificates.	27
Section 4.2	Mutilated, Destroyed, Lost or Stolen Certificates.	27
Section 4.3	Record Holders.	28
Section 4.4	Transfer Generally.	29
Section 4.5	Registration and Transfer of Limited Partner Interests.	29
Section 4.6	Transfer of the General Partner’s General Partner Interest.	30
Section 4.7	Transfer of Incentive Distribution Rights.	31
Section 4.8	Restrictions on Transfers.	31

Section 4.9	Citizenship Certificates; Non-citizen Assignees.	32
Section 4.10	Redemption of Partnership Interests of Non-citizen Assignees.	33

	ARTICLE V

	CAPITAL CONTRIBUTIONS AND ISSUANCE OF PARTNERSHIP INTERESTS

Section 5.1	Organizational Contributions.	34
Section 5.2	Contributions by the General Partner and its Affiliates.	35
Section 5.3	Contributions by Initial Limited Partners and Distributions to the General Partner and its Affiliates.	35
Section 5.4	Interest and Withdrawal.	36
Section 5.5	Capital Accounts.	36
Section 5.6	Issuances of Additional Partnership Securities.	39
Section 5.7	Limitations on Issuance of Additional Partnership Securities.	40
Section 5.8	Conversion of Subordinated Units.	43
Section 5.9	Limited Preemptive Right.	47
Section 5.10	Splits and Combinations.	47
Section 5.11	Fully Paid and Non-Assessable Nature of Limited Partner Interests.	48

	ARTICLE VI

	ALLOCATIONS AND DISTRIBUTIONS

Section 6.1	Allocations for Capital Account Purposes.	48
Section 6.2	Allocations for Tax Purposes.	56
Section 6.3	Requirement and Characterization of Distributions; Distributions to Record Holders.	58
Section 6.4	Distributions of Available Cash from Operating Surplus.	59
Section 6.5	Distributions of Available Cash from Capital Surplus.	61
Section 6.6	Adjustment of Minimum Quarterly Distribution and Target Distribution Levels.	61
Section 6.7	Special Provisions Relating to the Holders of Subordinated Units.	62
Section 6.8	Special Provisions Relating to the Holders of Incentive Distribution Rights.	62
Section 6.9	Entity-Level Taxation.	62

	ARTICLE VII

	MANAGEMENT AND OPERATION OF BUSINESS

Section 7.1	Management.	63
Section 7.2	Certificate of Limited Partnership.	65
Section 7.3	Restrictions on the General Partner’s Authority.	66

Section 7.4	Reimbursement of the General Partner.	66
Section 7.5	Outside Activities.	67
Section 7.6	Loans from the General Partner; Loans or Contributions from the Partnership; Contracts with Affiliates; Certain Restrictions on the General Partner.	69
Section 7.7	Indemnification.	70
Section 7.8	Liability of Indemnitees.	72
Section 7.9	Resolution of Conflicts of Interest.	73
Section 7.10	Other Matters Concerning the General Partner.	74
Section 7.11	Purchase or Sale of Partnership Securities.	75
Section 7.12	Registration Rights of the General Partner and its Affiliates.	75
Section 7.13	Reliance by Third Parties.	77

	ARTICLE VIII

	BOOKS, RECORDS, ACCOUNTING AND REPORTS

Section 8.1	Records and Accounting.	78
Section 8.2	Fiscal Year.	78
Section 8.3	Reports.	78

	ARTICLE IX

	TAX MATTERS

Section 9.1	Tax Returns and Information.	79
Section 9.2	Tax Elections.	79
Section 9.3	Tax Controversies.	80
Section 9.4	Withholding.	80

	ARTICLE X

	ADMISSION OF PARTNERS

Section 10.1	Admission of Initial Limited Partners.	80
Section 10.2	Admission of Substituted Limited Partner.	80
Section 10.3	Admission of Successor General Partner.	81
Section 10.4	Admission of Additional Limited Partners.	81
Section 10.5	Amendment of Agreement and Certificate of Limited Partnership.	82

	ARTICLE XI

	WITHDRAWAL OR REMOVAL OF PARTNERS

Section 11.1	Withdrawal of the General Partner.	82
Section 11.2	Removal of the General Partner.	84

iii

Section 11.3	Interest of Departing Partner and Successor General Partner.	84
Section 11.4	Termination of Subordination Period, Conversion of Subordinated Units and Extinguishment of Cumulative Common Unit Arrearages.	86
Section 11.5	Withdrawal of Limited Partners.	86

	ARTICLE XII

	DISSOLUTION AND LIQUIDATION

Section 12.1	Dissolution.	86
Section 12.2	Continuation of the Business of the Partnership After Dissolution.	87
Section 12.3	Liquidator.	87
Section 12.4	Liquidation.	88
Section 12.5	Cancellation of Certificate of Limited Partnership.	89
Section 12.6	Return of Contributions.	89
Section 12.7	Waiver of Partition.	89
Section 12.8	Capital Account Restoration.	89

	ARTICLE XIII

	AMENDMENT OF PARTNERSHIP AGREEMENT; MEETINGS; RECORD DATE

Section 13.1	Amendment to be Adopted Solely by the General Partner.	89
Section 13.2	Amendment Procedures.	91
Section 13.3	Amendment Requirements.	91
Section 13.4	Special Meetings.	92
Section 13.5	Notice of a Meeting.	92
Section 13.6	Record Date.	93
Section 13.7	Adjournment.	93
Section 13.8	Waiver of Notice; Approval of Meeting; Approval of Minutes.	93
Section 13.9	Quorum.	93
Section 13.10	Conduct of a Meeting.	94
Section 13.11	Action Without a Meeting.	94
Section 13.12	Voting and Other Rights.	95

	ARTICLE XIV

	MERGER

Section 14.1	Authority.	95
Section 14.2	Procedure for Merger or Consolidation.	96
Section 14.3	Approval by Limited Partners of Merger or Consolidation.	97
Section 14.4	Certificate of Merger.	97
Section 14.5	Effect of Merger.	98

	ARTICLE XV

	RIGHT TO ACQUIRE LIMITED PARTNER INTERESTS

Section 15.1	Right to Acquire Limited Partner Interests.	98

	ARTICLE XVI

	GENERAL PROVISIONS

Section 16.1	Addresses and Notices.	100
Section 16.2	Further Action.	101
Section 16.3	Binding Effect.	101
Section 16.4	Integration.	101
Section 16.5	Creditors.	101
Section 16.6	Waiver.	101
Section 16.7	Counterparts.	101
Section 16.8	Applicable Law.	102
Section 16.9	Invalidity of Provisions.	102
Section 16.10	Consent of Partners.	102

SECONDAMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP OF MARKWEST ENERGY PARTNERS, L.P.

THIS SECOND AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP OF MARKWEST ENERGY PARTNERS, L.P. dated effective as of February 28, 2007, is entered into by and among MarkWest Energy GP, L.L.C., a Delaware limited liability company, as the General Partner, MarkWest Michigan, Inc., a Delaware corporation, as an Initial Limited Partner, and MarkWest Hydrocarbon, Inc., a Delaware corporation, as the Organizational Limited Partner, (MarkWest Michigan, Inc. merged with and into MarkWest Hydrocarbon, Inc. effective December 28, 2006, with MarkWest Hydrocarbon, Inc. remaining as the surviving entity), together with any other Persons who become Partners in the Partnership or parties hereto as provided herein. In consideration of the covenants, conditions and agreements contained herein, the parties hereto hereby agree as follows:

ARTICLE I

DEFINITIONS

Section 1.1 Definitions.

The following definitions shall be for all purposes, unless otherwise clearly indicated to the contrary, applied to the terms used in this Agreement.

“Acquisition” means any transaction in which any Group Member acquires (through an asset acquisition, merger, stock acquisition or other form of investment) control over all or a portion of the assets, properties or business of another Person for the purpose of increasing the operating capacity or revenues of the Partnership Group from the operating capacity or revenues of the Partnership Group existing immediately prior to such transaction.

“Additional Book Basis” means the portion of any remaining Carrying Value of an Adjusted Property that is attributable to positive adjustments made to such Carrying Value as a result of Book-Up Events. For purposes of determining the extent that Carrying Value constitutes Additional Book Basis:

(i) Any negative adjustment made to the Carrying Value of an Adjusted Property as a result of either a Book-Down Event or a Book-Up Event shall first be deemed to offset or decrease that portion of the Carrying Value of such Adjusted Property that is attributable to any prior positive adjustments made thereto pursuant to a Book-Up Event or Book-Down Event.

(ii) If Carrying Value that constitutes Additional Book Basis is reduced as a result of a Book-Down Event and the Carrying Value of other property is increased as a result of such Book-Down Event, an allocable portion of any such increase in Carrying Value shall be treated as Additional Book Basis; provided that the amount treated as

Additional Book Basis pursuant hereto as a result of such Book-Down Event shall not exceed the amount by which the Aggregate Remaining Net Positive Adjustments after such Book-Down Event exceeds the remaining Additional Book Basis attributable to all of the Partnership’s Adjusted Property after such Book-Down Event (determined without regard to the application of this clause (ii) to such Book-Down Event).

“Additional Book Basis Derivative Items” means any Book Basis Derivative Items that are computed with reference to Additional Book Basis. To the extent that the Additional Book Basis attributable to all of the Partnership’s Adjusted Property as of the beginning of any taxable period exceeds the Aggregate Remaining Net Positive Adjustments as of the beginning of such period (the “Excess Additional Book Basis”), the Additional Book Basis Derivative Items for such period shall be reduced by the amount that bears the same ratio to the amount of Additional Book Basis Derivative Items determined without regard to this sentence as the Excess Additional Book Basis bears to the Additional Book Basis as of the beginning of such period.

“Additional Limited Partner” means a Person admitted to the Partnership as a Limited Partner pursuant to Section 10.4 and who is shown as such on the books and records of the Partnership.

“Adjusted Capital Account” means the Capital Account maintained for each Partner as of the end of each fiscal year of the Partnership, (a) increased by any amounts that such Partner is obligated to restore under the standards set by Treasury Regulation Section 1.704-1(b)(2)(ii)(c) (or is deemed obligated to restore under Treasury Regulation Sections 1.704-2(g) and 1.704-2(i)(5)) and (b) decreased by (i) the amount of all losses and deductions that, as of the end of such fiscal year, are reasonably expected to be allocated to such Partner in subsequent years under Sections 704(e)(2) and 706(d) of the Code and Treasury Regulation Section 1.751-1(b)(2)(ii), and (ii) the amount of all distributions that, as of the end of such fiscal year, are reasonably expected to be made to such Partner in subsequent years in accordance with the terms of this Agreement or otherwise to the extent they exceed offsetting increases to such Partner’s Capital Account that are reasonably expected to occur during (or prior to) the year in which such distributions are reasonably expected to be made (other than increases as a result of a minimum gain chargeback pursuant to Section 6.1(d)(i) or 6.1(d)(ii)). The foregoing definition of Adjusted Capital Account is intended to comply with the provisions of Treasury Regulation Section 1.704-1(b)(2)(ii)(d) and shall be interpreted consistently therewith. The “Adjusted Capital Account” of a Partner in respect of a General Partner Interest, a Common Unit, a Subordinated Unit or an Incentive Distribution Right or any other specified interest in the Partnership shall be the amount which such Adjusted Capital Account would be if such General Partner Interest, Common Unit, Subordinated Unit, Incentive Distribution Right or other interest in the Partnership were the only interest in the Partnership held by such Partner from and after the date on which such General Partner Interest, Common Unit, Subordinated Unit, Incentive Distribution Right or other interest was first issued.

“Adjusted Operating Surplus” means, with respect to any period, Operating Surplus generated during such period (a) less (i) any net increase in Working Capital Borrowings with respect to such period and (ii) any net reduction in cash reserves for Operating Expenditures with

respect to such period not relating to an Operating Expenditure made with respect to such period, and (b) plus (i) any net decrease in Working Capital Borrowings with respect to such period, and (ii) any net increase in cash reserves for Operating Expenditures with respect to such period required by any debt instrument for the repayment of principal, interest or premium. Adjusted Operating Surplus does not include that portion of Operating Surplus included in clause (a)(i) of the definition of Operating Surplus.

“Adjusted Property” means any property the Carrying Value of which has been adjusted pursuant to Section 5.5(d)(i) or 5.5(d)(ii).

“Affiliate” means, with respect to any Person, any other Person that directly or indirectly through one or more intermediaries controls, is controlled by or is under common control with, the Person in question. As used herein, the term “control” means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through ownership of voting securities, by contract or otherwise.

“Aggregate Remaining Net Positive Adjustments” means, as of the end of any taxable period, the sum of the Remaining Net Positive Adjustments of all the Partners.

“Agreed Allocation” means any allocation, other than a Required Allocation, of an item of income, gain, loss or deduction pursuant to the provisions of Section 6.1, including, without limitation, a Curative Allocation (if appropriate to the context in which the term “Agreed Allocation” is used).

“Agreed Value” of any Contributed Property means the fair market value of such property or other consideration at the time of contribution as determined by the General Partner using such reasonable method of valuation as it may adopt. The General Partner shall, in its discretion, use such method as it deems reasonable and appropriate to allocate the aggregate Agreed Value of Contributed Properties contributed to the Partnership in a single or integrated transaction among each separate property on a basis proportional to the fair market value of each Contributed Property.

“Agreement” means this Amended and Restated Agreement of Limited Partnership of MarkWest Energy Partners, L.P., as it may be amended, supplemented or restated from time to time.

“APB 25” means Accounting Principles Board Opinion Number 25, an accounting principle governing accounting for stock issued to employees.

“Assignee” means a Non-citizen Assignee or a Person to whom one or more Limited Partner Interests have been transferred in a manner permitted under this Agreement and who has executed and delivered a Transfer Application as required by this Agreement, but who has not been admitted as a Substituted Limited Partner.

“Associate” means, when used to indicate a relationship with any Person, (a) any corporation or organization of which such Person is a director, officer or partner or is, directly or indirectly, the owner of 20% or more of any class of voting stock or other voting interest; (b) any trust or other estate in which such Person has at least a 20% beneficial interest or as to which such Person serves as trustee or in a similar fiduciary capacity; and (c) any relative or spouse of such Person, or any relative of such spouse, who has the same principal residence as such Person.

“Available Cash” means, with respect to any Quarter ending prior to the Liquidation Date:

(a) the sum of (i) all cash and cash equivalents of the Partnership Group on hand at the end of such Quarter, and (ii) all additional cash and cash equivalents of the Partnership Group on hand on the date of determination of Available Cash with respect to such Quarter resulting from Working Capital Borrowings made subsequent to the end of such Quarter, less

(b) the amount of any cash reserves that are necessary or appropriate in the reasonable discretion of the General Partner to (i) provide for the proper conduct of the business of the Partnership Group (including reserves for future capital expenditures and for anticipated future credit needs of the Partnership Group) subsequent to such Quarter, (ii) comply with applicable law or any loan agreement, security agreement, mortgage, debt instrument or other agreement or obligation to which any Group Member is a party or by which it is bound or its assets are subject or (iii) provide funds for distributions under Section 6.4 or 6.5 in respect of any one or more of the next four Quarters; provided, however, that the General Partner may not establish cash reserves pursuant to (iii) above if the effect of such reserves would be that the Partnership is unable to distribute the Minimum Quarterly Distribution on all Common Units, plus any Cumulative Common Unit Arrearage on all Common Units, with respect to such Quarter; and, provided further, that disbursements made by a Group Member or cash reserves established, increased or reduced after the end of such Quarter but on or before the date of determination of Available Cash with respect to such Quarter shall be deemed to have been made, established, increased or reduced, for purposes of determining Available Cash, within such Quarter if the General Partner so determines.

Notwithstanding the foregoing, “Available Cash” with respect to the Quarter in which the Liquidation Date occurs and any subsequent Quarter shall equal zero.

“Book Basis Derivative Items” means any item of income, deduction, gain or loss included in the determination of Net Income or Net Loss that is computed with reference to the Carrying Value of an Adjusted Property (e.g., depreciation, depletion, or gain or loss with respect to an Adjusted Property).

“Book-Down Event” means an event which triggers a negative adjustment to the Capital Accounts of the Partners pursuant to Section 5.5(d).

“Book-Tax Disparity” means with respect to any item of Contributed Property or Adjusted Property, as of the date of any determination, the difference between the Carrying Value of such Contributed Property or Adjusted Property and the adjusted basis thereof for federal income tax purposes as of such date. A Partner’s share of the Partnership’s Book-Tax Disparities in all of its Contributed Property and Adjusted Property will be reflected by the difference between such Partner’s Capital Account balance as maintained pursuant to Section 5.5 and the hypothetical balance of such Partner’s Capital Account computed as if it had been maintained strictly in accordance with federal income tax accounting principles.

“Book-Up Event” means an event which triggers a positive adjustment to the Capital Accounts of the Partners pursuant to Section 5.5(d).

“Business Day” means Monday through Friday of each week, except that a legal holiday recognized as such by the government of the United States of America or the State of Colorado shall not be regarded as a Business Day.

“Capital Account” means the capital account maintained for a Partner pursuant to Section 5.5. The “Capital Account” of a Partner in respect of a General Partner Interest, a Common Unit, a Subordinated Unit, an Incentive Distribution Right or any other Partnership Interest shall be the amount which such Capital Account would be if such General Partner Interest, Common Unit, Subordinated Unit, Incentive Distribution Right or other Partnership Interest were the only interest in the Partnership held by such Partner from and after the date on which such General Partner Interest, Common Unit, Subordinated Unit, Incentive Distribution Right or other Partnership Interest was first issued.

“Capital Contribution” means any cash, cash equivalents or the Net Agreed Value of Contributed Property that a Partner contributes to the Partnership pursuant to this Agreement or the Contribution Agreement.

“Capital Improvement” means any (a) addition or improvement to the capital assets owned by any Group Member or (b) acquisition of existing, or the construction of new, capital assets (including, without limitation, natural gas processing plants and natural gas liquids pipelines, fractionation plants and storage and distribution facilities and related assets), in each case if such addition, improvement, acquisition or construction is made to increase the operating capacity or revenues of the Partnership Group from the operating capacity or revenues of the Partnership Group existing immediately prior to such addition, improvement, acquisition or construction.

“Capital Surplus” has the meaning assigned to such term in Section 6.3(a).

“Carrying Value” means (a) with respect to a Contributed Property, the Agreed Value of such property reduced (but not below zero) by all depreciation, amortization and cost recovery deductions charged to the Partners’ and Assignees’ Capital Accounts in respect of such Contributed Property, and (b) with respect to any other Partnership property, the adjusted basis of such property for federal income tax purposes, all as of the time of determination. The

Carrying Value of any property shall be adjusted from time to time in accordance with Sections 5.5(d)(i) and 5.5(d)(ii) and to reflect changes, additions or other adjustments to the Carrying Value for dispositions and acquisitions of Partnership properties, as deemed appropriate by the General Partner.

“Cause” means a court of competent jurisdiction has entered a final, non-appealable judgment finding the General Partner liable for actual fraud, gross negligence or willful or wanton misconduct in its capacity as a general partner of the Partnership.

“Certificate” means a certificate (i) substantially in the form of Exhibit A to this Agreement, (ii) issued in global form in accordance with the rules and regulations of the Depositary or (iii) in such other form as may be adopted by the General Partner in its discretion, issued by the Partnership evidencing ownership of one or more Common Units or a certificate, in such form as may be adopted by the General Partner in its discretion, issued by the Partnership evidencing ownership of one or more other Partnership Securities.

“Certificate of Limited Partnership” means the Certificate of Limited Partnership of the Partnership filed with the Secretary of State of the State of Delaware as referenced in Section 2.1, as such Certificate of Limited Partnership may be amended, supplemented or restated from time to time.

“Citizenship Certification” means a properly completed certificate in such form as may be specified by the General Partner by which an Assignee or a Limited Partner certifies that he (and if he is a nominee holding for the account of another Person, that to the best of his knowledge such other Person) is an Eligible Citizen.

“Claim” has the meaning assigned to such term in Section 7.12(c).

“Closing Date” means the first date on which Common Units are sold by the Partnership to the Underwriters pursuant to the provisions of the Underwriting Agreement.

“Closing Price” has the meaning assigned to such term in Section 15.1(a).

“▇▇▇▇ Contributions” means those contributions made by the General Partner pursuant to Section 5.2(c).

“Code” means the Internal Revenue Code of 1986, as amended and in effect from time to time. Any reference herein to a specific section or sections of the Code shall be deemed to include a reference to any corresponding provision of successor law.

“Combined Interest” has the meaning assigned to such term in Section 11.3(a).

“Commission” means the United States Securities and Exchange Commission.

“Common Unit” means a Partnership Security representing a fractional part of the Partnership Interests of all Limited Partners and Assignees, and having the rights and obligations

specified with respect to Common Units in this Agreement. The term “Common Unit” does not refer to a Subordinated Unit prior to its conversion into a Common Unit pursuant to the terms hereof.

“Common Unit Arrearage” means, with respect to any Common Unit, whenever issued, as to any Quarter within the Subordination Period, the excess, if any, of (a) the Minimum Quarterly Distribution with respect to a Common Unit in respect of such Quarter over (b) the sum of all Available Cash distributed with respect to a Common Unit in respect of such Quarter pursuant to Section 6.4(a)(i).

“Conflicts Committee” means a committee of the Board of Directors of the General Partner composed entirely of two or more directors who are not (a) security holders, officers or employees of the General Partner, (b) officers, directors or employees of any Affiliate of the General Partner or (c) holders of any ownership interest in the Partnership Group other than Common Units and who also meet the independence standards required to serve on an audit committee of a board of directors by the National Securities Exchange on which the Common Units are listed for trading.

“Contributed Property” means each property or other asset, in such form as may be permitted by the Delaware Act, but excluding cash, contributed to the Partnership. Once the Carrying Value of a Contributed Property is adjusted pursuant to Section 5.5(d), such property shall no longer constitute a Contributed Property, but shall be deemed an Adjusted Property.

“Contribution Agreement” means that certain Contribution, Conveyance and Assumption Agreement, dated as of the Closing Date, among the General Partner, the Partnership, the Operating Company, MarkWest Hydrocarbon, Inc. and certain other parties, together with the additional conveyance documents and instruments contemplated or referenced thereunder.

“Cumulative Common Unit Arrearage” means, with respect to any Common Unit, whenever issued, and as of the end of any Quarter, the excess, if any, of (a) the sum resulting from adding together the Common Unit Arrearage as to an Initial Common Unit for each of the Quarters within the Subordination Period ending on or before the last day of such Quarter over (b) the sum of any distributions theretofore made pursuant to Section 6.4(a)(ii) and the second sentence of Section 6.5 with respect to an Initial Common Unit (including any distributions to be made in respect of the last of such Quarters).

“Curative Allocation” means any allocation of an item of income, gain, deduction, loss or credit pursuant to the provisions of Section 6.1(d)(xi).

“Current Market Price” has the meaning assigned to such term in Section 15.1(a).

“Delaware Act” means the Delaware Revised Uniform Limited Partnership Act, 6 Del C. Section 17-101, et seq., as amended, supplemented or restated from time to time, and any successor to such statute.

“Departing Partner” means a former General Partner from and after the effective date of any withdrawal or removal of such former General Partner pursuant to Section 11.1 or 11.2.

“Depositary” means, with respect to any Units issued in global form, The Depository Trust Company and its successors and permitted assigns.

“Economic Risk of Loss” has the meaning set forth in Treasury Regulation Section 1.752-2(a).

“Eligible Citizen” means a Person qualified to own interests in real property in jurisdictions in which any Group Member does business or proposes to do business from time to time, and whose status as a Limited Partner or Assignee does not or would not subject such Group Member to a significant risk of cancellation or forfeiture of any of its properties or any interest therein.

“Event of Withdrawal” has the meaning assigned to such term in Section 11.1(a).

“FAS 123R” means Statement of Financial Accounting Standards Number 123R, an accounting principle governing accounting for share based payments.

“Final Subordinated Units” has the meaning assigned to such term in Section 6.1(d)(x).

“First Liquidation Target Amount” has the meaning assigned to such term in Section 6.1(c)(i)(D).

“First Target Distribution” means $0.275 per Unit per Quarter (or, with respect to the period commencing on the Closing Date and ending on June 30, 2002, it means the product of $0.275 multiplied by a fraction of which the numerator is the number of days in such period, and of which the denominator is 91), subject to adjustment in accordance with Sections 6.6 and 6.9.

“Fully Diluted Basis” means, when calculating the number of Outstanding Units for any period, a basis that includes, in addition to the Outstanding Units, all Partnership Securities and options, rights, warrants and appreciation rights relating to an equity interest in the Partnership (a) that are convertible into or exercisable or exchangeable for Units that are senior to or pari passu with the Subordinated Units, (b) whose conversion, exercise or exchange price is less than the Current Market Price on the date of such calculation, and (c) that may be converted into or exercised or exchanged for such Units prior to or during the Quarter following the end of the last Quarter contained in the period for which the calculation is being made without the satisfaction of any contingency beyond the control of the holder other than the payment of consideration and the compliance with administrative mechanics applicable to such conversion, exercise or exchange; provided that for purposes of determining the number of Outstanding Units on a Fully Diluted Basis when calculating whether the Subordination Period has ended or Subordinated Units are entitled to convert into Common Units pursuant to Section 5.8, such Partnership Securities, options, rights, warrants and appreciation rights shall be deemed to have been

Outstanding Units only for the four Quarters that comprise the last four Quarters of the measurement period; provided, further, that if consideration will be paid to any Group Member in connection with such conversion, exercise or exchange, the number of Units to be included in such calculation shall be that number equal to the difference between (i) the number of Units issuable upon such conversion, exercise or exchange and (ii) the number of Units which such consideration would purchase at the Current Market Price.

“General Partner” means MarkWest Energy GP, L.L.C. and its successors and permitted assigns as general partner of the Partnership.

“General Partner Interest” means the ownership interest of the General Partner in the Partnership (in its capacity as a general partner without reference to any Limited Partner Interest held by it) which may be evidenced by Partnership Securities or a combination thereof or interest therein, and includes any and all benefits to which the General Partner is entitled as provided in this Agreement, together with all obligations of the General Partner to comply with the terms and provisions of this Agreement.

“Group” means a Person that with or through any of its Affiliates or Associates has any agreement, arrangement or understanding for the purpose of acquiring, holding, voting (except voting pursuant to a revocable proxy or consent given to such Person in response to a proxy or consent solicitation made to 10 or more Persons) or disposing of any Partnership Securities with any other Person that beneficially owns, or whose Affiliates or Associates beneficially own, directly or indirectly, Partnership Securities.

“Group Member” means a member of the Partnership Group.

“Holder” as used in Section 7.12, has the meaning assigned to such term in Section 7.12(a).

“Incentive Distribution Right” means a non-voting Limited Partner Interest issued to the General Partner in connection with the transfer of all of its membership interests in MarkWest Energy Appalachia, L.L.C. to the Partnership pursuant to Section 5.2, which Partnership Interest will confer upon the holder thereof only the rights and obligations specifically provided in this Agreement with respect to Incentive Distribution Rights (and no other rights otherwise available to or other obligations of a holder of a Partnership Interest). Notwithstanding anything in this Agreement to the contrary, the holder of an Incentive Distribution Right shall not be entitled to vote such Incentive Distribution Right on any Partnership matter except as may otherwise be required by law.

“Incentive Distributions” means any amount of cash distributed to the holders of the Incentive Distribution Rights pursuant to Sections 6.4(a)(v), (vi) and (vii) and 6.4(b)(iii), (iv) and (v).

“Indemnified Persons” has the meaning assigned to such term in Section 7.12(c).

“Indemnitee” means (a) the General Partner, (b) any Departing Partner, (c) any Person who is or was an Affiliate of the General Partner or any Departing Partner, (d) any Person who is or was a member, partner, officer, director, employee, agent or trustee of any Group Member, the General Partner or any Departing Partner or any Affiliate of any Group Member, the General Partner or any Departing Partner, and (e) any Person who is or was serving at the request of the General Partner or any Departing Partner or any Affiliate of the General Partner or any Departing Partner as an officer, director, employee, member, partner, agent, fiduciary or trustee of another Person; provided, that a Person shall not be an Indemnitee by reason of providing, on a fee-for-services basis, trustee, fiduciary or custodial services.

“Initial Common Units” means the Common Units sold in the Initial Offering.

“Initial Limited Partners” means MarkWest Energy GP, L.L.C., MarkWest Michigan, Inc. and the Underwriters, in each case upon being admitted to the Partnership in accordance with Section 10.1.

“Initial Offering” means the initial offering and sale of Common Units to the public, as described in the Registration Statement.

“Initial Unit Price” means (a) with respect to the Common Units and the Subordinated Units, the initial public offering price per Common Unit at which the Underwriters offered the Common Units to the public for sale as set forth on the cover page of the prospectus included as part of the Registration Statement and first issued at or after the time the Registration Statement first became effective or (b) with respect to any other class or series of Units, the price per Unit at which such class or series of Units is initially sold by the Partnership, as determined by the General Partner, in each case adjusted as the General Partner determines to be appropriate to give effect to any distribution, subdivision or combination of Units.

“Interim Capital Transactions” means the following transactions if they occur prior to the Liquidation Date: (a) borrowings, refinancings or refundings of indebtedness and sales of debt securities (other than Working Capital Borrowings and other than for items purchased on open account in the ordinary course of business) by any Group Member; (b) sales of equity interests by any Group Member (including the Common Units sold to the Underwriters pursuant to the exercise of their over-allotment option); and (c) sales or other voluntary or involuntary dispositions of any assets of any Group Member other than (i) sales or other dispositions of inventory, accounts receivable and other assets in the ordinary course of business, and (ii) sales or other dispositions of assets as part of normal retirements or replacements.

“Issue Price” means the price at which a Unit is purchased from the Partnership, after taking into account any sales commission or underwriting discount charged to the Partnership.

“Limited Partner” means, unless the context otherwise requires, (a) the Organizational Limited Partner prior to its withdrawal from the Partnership, each Initial Limited Partner, each Substituted Limited Partner, each Additional Limited Partner and any Departing Partner upon the change of its status from General Partner to Limited Partner pursuant to Section 11.3 or (b)

solely for purposes of Articles V, VI, VII and IX, each Assignee; provided, however, that when the term “Limited Partner” is used herein in the context of any vote or other approval, including without limitation Articles XIII and XIV, such term shall not, solely for such purpose, include any holder of an Incentive Distribution Right except as may otherwise be required by law.

“Limited Partner Interest” means the ownership interest of a Limited Partner or Assignee in the Partnership, which may be evidenced by Common Units, Subordinated Units, Incentive Distribution Rights or other Partnership Securities or a combination thereof or interest therein, and includes any and all benefits to which such Limited Partner or Assignee is entitled as provided in this Agreement, together with all obligations of such Limited Partner or Assignee to comply with the terms and provisions of this Agreement; provided, however, that when the term “Limited Partner Interest” is used herein in the context of any vote or other approval, including without limitation Articles XIII and XIV, such term shall not, solely for such purpose, include any holder of an Incentive Distribution Right except as may otherwise be required by law.

“Liquidation Date” means (a) in the case of an event giving rise to the dissolution of the Partnership of the type described in clauses (a) and (b) of the first sentence of Section 12.2, the date on which the applicable time period during which the holders of Outstanding Units have the right to elect to reconstitute the Partnership and continue its business has expired without such an election being made, and (b) in the case of any other event giving rise to the dissolution of the Partnership, the date on which such event occurs.

“Liquidator” means one or more Persons selected by the General Partner to perform the functions described in Section 12.3 as liquidating trustee of the Partnership within the meaning of the Delaware Act.

“Merger Agreement” has the meaning assigned to such term in Section 14.1.

“Minimum Quarterly Distribution” means $0.25 per Unit per Quarter (or with respect to the period commencing on the Closing Date and ending on June 30, 2002, it means the product of $0.25 multiplied by a fraction of which the numerator is the number of days in such period and of which the denominator is 91), subject to adjustment in accordance with Sections 6.6 and 6.9.

“National Securities Exchange” means an exchange registered with the Commission under Section 6(a) of the Securities Exchange Act of 1934, as amended, supplemented or restated from time to time, and any successor to such statute, or the Nasdaq Stock Market or any successor thereto.

“Net Agreed Value” means, (a) in the case of any Contributed Property, the Agreed Value of such property reduced by any liabilities either assumed by the Partnership upon such contribution or to which such property is subject when contributed, and (b) in the case of any property distributed to a Partner or Assignee by the Partnership, the Partnership’s Carrying Value of such property (as adjusted pursuant to Section 5.5(d)(ii)) at the time such property is distributed, reduced by any indebtedness either assumed by such Partner or Assignee upon such

distribution or to which such property is subject at the time of distribution, in either case, as determined under Section 752 of the Code.

“Net Income” means, for any taxable year, the excess, if any, of the Partnership’s items of income and gain (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable year over the Partnership’s items of loss and deduction (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable year. The items included in the calculation of Net Income shall be determined in accordance with Section 5.5(b) and shall not include any items specially allocated under Section 6.1(d); provided that the determination of the items that have been specially allocated under Section 6.1(d) shall be made as if Section 6.1(d)(xii) were not in this Agreement.

“Net Loss” means, for any taxable year, the excess, if any, of the Partnership’s items of loss and deduction (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable year over the Partnership’s items of income and gain (other than those items taken into account in the computation of Net Termination Gain or Net Termination Loss) for such taxable year. The items included in the calculation of Net Loss shall be determined in accordance with Section 5.5(b) and shall not include any items specially allocated under Section 6.1(d); provided that the determination of the items that have been specially allocated under Section 6.1(d) shall be made as if Section 6.1(d)(xii) were not in this Agreement.

“Net Positive Adjustments” means, with respect to any Partner, the excess, if any, of the total positive adjustments over the total negative adjustments made to the Capital Account of such Partner pursuant to Book-Up Events and Book-Down Events.

“Net Termination Gain” means, for any taxable year, the sum, if positive, of all items of income, gain, loss or deduction recognized by the Partnership after the Liquidation Date. The items included in the determination of Net Termination Gain shall be determined in accordance with Section 5.5(b) and shall not include any items of income, gain or loss specially allocated under Section 6.1(d).

“Net Termination Loss” means, for any taxable year, the sum, if negative, of all items of income, gain, loss or deduction recognized by the Partnership after the Liquidation Date. The items included in the determination of Net Termination Loss shall be determined in accordance with Section 5.5(b) and shall not include any items of income, gain or loss specially allocated under Section 6.1(d).

“New ▇▇▇▇ Plant” means the Gas Extraction Plant designed to the specifications contained in the Amended and Restated Agreement for Construction and Removal (▇▇▇▇ Plant) dated as of December 31, 2004 entered into between MarkWest Hydrocarbon, Inc. and MarkWest Energy Appalachia, L.L.C., replacing and superceding that certain Agreement for Construction and Removal dated October 10, 2003.

“Non-citizen Assignee” means a Person whom the General Partner has determined in its discretion does not constitute an Eligible Citizen and as to whose Partnership Interest the General Partner has become the Substituted Limited Partner, pursuant to Section 4.9.

“Nonrecourse Built-in Gain” means with respect to any Contributed Properties or Adjusted Properties that are subject to a mortgage or pledge securing a Nonrecourse Liability, the amount of any taxable gain that would be allocated to the Partners pursuant to Sections 6.2(b)(i)(A), 6.2(b)(ii)(A) and 6.2(b)(iii) if such properties were disposed of in a taxable transaction in full satisfaction of such liabilities and for no other consideration.

“Nonrecourse Deductions” means any and all items of loss, deduction or expenditure (including, without limitation, any expenditure described in Section 705(a)(2)(B) of the Code) that, in accordance with the principles of Treasury Regulation Section 1.704-2(b), are attributable to a Nonrecourse Liability.

“Nonrecourse Liability” has the meaning set forth in Treasury Regulation Section 1.752-1(a)(2).

“Notice of Election to Purchase” has the meaning assigned to such term in Section 15.1(b).

“Omnibus Agreement” means that Omnibus Agreement, dated as of the Closing Date, among MarkWest Hydrocarbon, Inc., the General Partner, the Partnership and the Operating Company.

“Operating Company” means MarkWest Energy Operating Company, L.L.C., a Delaware limited liability company, and any successors thereto.

“Operating Company Agreement” means the Amended and Restated Limited Liability Company Agreement of the Operating Company, as it may be amended, supplemented or restated from time to time.

“Operating Expenditures” means all Partnership Group expenditures, including, but not limited to, taxes, reimbursements of the General Partner, repayment of Working Capital Borrowings, debt service payments and capital expenditures, subject to the following:

(a) Payments (including prepayments) of principal of and premium on indebtedness other than Working Capital Borrowings shall not constitute Operating Expenditures; and

(b) Operating Expenditures shall not include (i) capital expenditures made for Acquisitions or for Capital Improvements, (ii) payment of transaction expenses relating to Interim Capital Transactions or (iii) distributions to Partners. Where capital expenditures are made in part for Acquisitions or for Capital Improvements and in part for other purposes, the General Partner’s good faith allocation between the amounts paid for each shall be conclusive.

“Operating Surplus” means, with respect to any period ending prior to the Liquidation Date, on a cumulative basis and without duplication,

(a) the sum of (i) $6.3 million plus all cash and cash equivalents of the Partnership Group on hand as of the close of business on the Closing Date, (ii) all cash receipts of the Partnership Group for the period beginning on the Closing Date and ending with the last day of such period, other than cash receipts from Interim Capital Transactions (except to the extent specified in Section 6.5) and (iii) all cash receipts of the Partnership Group after the end of such period but on or before the date of determination of Operating Surplus with respect to such period resulting from Working Capital Borrowings, less

(b) the sum of (i) Operating Expenditures for the period beginning on the Closing Date and ending with the last day of such period and (ii) the amount of cash reserves that is necessary or advisable in the reasonable discretion of the General Partner to provide funds for future Operating Expenditures; provided, however, that disbursements made (including contributions to a Group Member or disbursements on behalf of a Group Member) or cash reserves established, increased or reduced after the end of such period but on or before the date of determination of Available Cash with respect to such period shall be deemed to have been made, established, increased or reduced, for purposes of determining Operating Surplus, within such period if the General Partner so determines.

Notwithstanding the foregoing, “Operating Surplus” with respect to the Quarter in which the Liquidation Date occurs and any subsequent Quarter shall equal zero.

“Opinion of Counsel” means a written opinion of counsel (who may be regular counsel to the Partnership or the General Partner or any of its Affiliates) acceptable to the General Partner in its reasonable discretion.

“Option Closing Date” means the date or dates on which any Common Units are sold by the Partnership to the Underwriters upon exercise of the Over-Allotment Option.

“Organizational Limited Partner” means MarkWest Hydrocarbon, Inc. in its capacity as the organizational limited partner of the Partnership pursuant to this Agreement.

“Outstanding” means, with respect to Partnership Securities, all Partnership Securities that are issued by the Partnership and reflected as outstanding on the Partnership’s books and records as of the date of determination; provided, however, that if at any time any Person or Group (other than the General Partner or its Affiliates) beneficially owns 20% or more of any Outstanding Partnership Securities of any class then Outstanding, all Partnership Securities owned by such Person or Group shall not be voted on any matter and shall not be considered to be Outstanding when sending notices of a meeting of Limited Partners to vote on any matter (unless otherwise required by law), calculating required votes, determining the presence of a quorum or for other similar purposes under this Agreement, except that Common Units so owned shall be considered to be Outstanding for purposes of Section 11.1(b)(iv) (such Common Units shall not, however, be treated as a separate class of Partnership Securities for purposes of this

Agreement); provided, further, that the foregoing limitation shall not apply (i) to any Person or Group who acquired 20% or more of any Outstanding Partnership Securities of any class then Outstanding directly from the General Partner or its Affiliates, (ii) to any Person or Group who acquired 20% or more of any Outstanding Partnership Securities of any class then Outstanding directly or indirectly from a Person or Group described in clause (i) provided that the General Partner shall have notified such Person or Group in writing that such limitation shall not apply, or (iii) to any Person or Group who acquired 20% or more of any Partnership Securities issued by the Partnership with the prior approval of the board of directors of the General Partner.

“Over-Allotment Option” means the over-allotment option granted to the Underwriters by the Partnership pursuant to the Underwriting Agreement.

“Parity Units” means Common Units and all other Units of any other class or series that have the right (i) to receive distributions of Available Cash from Operating Surplus pursuant to each of subclauses (a)(i) and (a)(ii) of Section 6.4 in the same order of priority with respect to the participation of Common Units in such distributions or (ii) to participate in allocations of Net Termination Gain pursuant to Section 6.1(c)(i)(B) in the same order of priority with the Common Units, in each case regardless of whether the amounts or value so distributed or allocated on each Parity Unit equals the amount or value so distributed or allocated on each Common Unit. Units whose participation in such (i) distributions of Available Cash from Operating Surplus and (ii) allocations of Net Termination Gain are subordinate in order of priority to such distributions and allocations on Common Units shall not constitute Parity Units even if such Units are convertible under certain circumstances into Common Units or Parity Units.

“Partner Nonrecourse Debt” has the meaning set forth in Treasury Regulation Section 1.704-2(b)(4).

“Partner Nonrecourse Debt Minimum Gain” has the meaning set forth in Treasury Regulation Section 1.704-2(i)(2).

“Partner Nonrecourse Deductions” means any and all items of loss, deduction or expenditure (including, without limitation, any expenditure described in Section 705(a)(2)(B) of the Code) that, in accordance with the principles of Treasury Regulation Section 1.704-2(i), are attributable to a Partner Nonrecourse Debt.

“Partners” means the General Partner and the Limited Partners.

“Partnership” means MarkWest Energy Partners, L.P., a Delaware limited partnership, and any successors thereto.

“Partnership Group” means the Partnership, the Operating Company and any Subsidiary of any such entity, treated as a single consolidated entity.

“Partnership Interest” means an interest in the Partnership, which shall include the General Partner Interest and Limited Partner Interests.

“Partnership Minimum Gain” means that amount determined in accordance with the principles of Treasury Regulation Section 1.704-2(d).

“Partnership Security” means any class or series of equity interest in the Partnership (but excluding any options, rights, warrants and appreciation rights relating to an equity interest in the Partnership), including without limitation, Common Units, Subordinated Units and Incentive Distribution Rights.

“Percentage Interest” means as of any date of determination (a) as to the General Partner (in its capacity as General Partner without reference to any Limited Partner Interests held by it), 2.0%, (b) as to any Unitholder or Assignee holding Units, the product obtained by multiplying (i) 98% less the percentage applicable to paragraph (c) by (ii) the quotient obtained by dividing (A) the number of Units held by such Unitholder or Assignee by (B) the total number of all Outstanding Units, and (c) as to the holders of additional Partnership Securities issued by the Partnership in accordance with Section 5.6, the percentage established as a part of such issuance. The Percentage Interest with respect to an Incentive Distribution Right shall at all times be zero.

“Person” means an individual or a corporation, limited liability company, partnership, joint venture, trust, unincorporated organization, association, government agency or political subdivision thereof or other entity.

“Per Unit Capital Amount” means, as of any date of determination, the Capital Account, stated on a per Unit basis, underlying any Unit held by a Person other than the General Partner or any Affiliate of the General Partner who holds Units.

“Pro Rata” means (a) when modifying Units or any class thereof, apportioned equally among all designated Units in accordance with their relative Percentage Interests, (b) when modifying Partners and Assignees, apportioned among all Partners and Assignees in accordance with their relative Percentage Interests and (c) when modifying holders of Incentive Distribution Rights, apportioned equally among all holders of Incentive Distribution Rights in accordance with the relative number of Incentive Distribution Rights held by each such holder.

“Purchase Date” means the date determined by the General Partner as the date for purchase of all Outstanding Units of a certain class (other than Units owned by the General Partner and its Affiliates) pursuant to Article XV.

“Quarter” means, unless the context requires otherwise, a fiscal quarter, or, with respect to the first fiscal quarter after the Closing Date, the portion of such fiscal quarter after the Closing Date, of the Partnership.

“Recapture Income” means any gain recognized by the Partnership (computed without regard to any adjustment required by Section 734 or Section 743 of the Code) upon the disposition of any property or asset of the Partnership, which gain is characterized as ordinary income because it represents the recapture of deductions previously taken with respect to such property or asset.

“Record Date” means the date established by the General Partner for determining (a) the identity of the Record Holders entitled to notice of, or to vote at, any meeting of Limited Partners or entitled to vote by ballot or give approval of Partnership action in writing without a meeting or entitled to exercise rights in respect of any lawful action of Limited Partners or (b) the identity of Record Holders entitled to receive any report or distribution or to participate in any offer.

“Record Holder” means the Person in whose name a Common Unit is registered on the books of the Transfer Agent as of the opening of business on a particular Business Day, or with respect to other Partnership Securities, the Person in whose name any such other Partnership Security is registered on the books which the General Partner has caused to be kept as of the opening of business on such Business Day.

“Redeemable Interests” means any Partnership Interests for which a redemption notice has been given, and has not been withdrawn, pursuant to Section 4.10.

“Registration Statement” means the Registration Statement on Form S-1 (Registration No. 333-81780) as it has been or as it may be amended or supplemented from time to time, filed by the Partnership with the Commission under the Securities Act to register the offering and sale of the Common Units in the Initial Offering.

“Remaining Net Positive Adjustments” means as of the end of any taxable period, (i) with respect to the Unitholders holding Common Units or Subordinated Units, the excess of (a) the Net Positive Adjustments of the Unitholders holding Common Units or Subordinated Units as of the end of such period over (b) the sum of those Partners’ Share of Additional Book Basis Derivative Items for each prior taxable period, (ii) with respect to the General Partner (as holder of the General Partner Interest), the excess of (a) the Net Positive Adjustments of the General Partner as of the end of such period over (b) the sum of the General Partner’s Share of Additional Book Basis Derivative Items with respect to the General Partner Interest for each prior taxable period, and (iii) with respect to the holders of Incentive Distribution Rights, the excess of (a) the Net Positive Adjustments of the holders of Incentive Distribution Rights as of the end of such period over (b) the sum of the Share of Additional Book Basis Derivative Items of the holders of the Incentive Distribution Rights for each prior taxable period.

“Required Allocations” means (a) any limitation imposed on any allocation of Net Losses or Net Termination Losses under Section 6.1(b) or 6.1(c)(ii) and (b) any allocation of an item of income, gain, loss or deduction pursuant to Section 6.1(d)(i), 6.1(d)(ii), 6.1(d)(iv), 6.1(d)(vii) or 6.1(d)(ix).

“Residual Gain” or “Residual Loss” means any item of gain or loss, as the case may be, of the Partnership recognized for federal income tax purposes resulting from a sale, exchange or other disposition of a Contributed Property or Adjusted Property, to the extent such item of gain or loss is not allocated pursuant to Section 6.2(b)(i)(A) or 6.2(b)(ii)(A), respectively, to eliminate Book-Tax Disparities.

“Restricted Business” has the meaning assigned to such term in the Omnibus Agreement.

“Second Liquidation Target Amount” has the meaning assigned to such term in Section 6.1(c)(i)(E).

“Second Target Distribution” means $0.3125 per Unit per Quarter (or, with respect to the period commencing on the Closing Date and ending on June 30, 2002, it means the product of $0.3125 multiplied by a fraction of which the numerator is equal to the number of days in such period and of which the denominator is 91), subject to adjustment in accordance with Sections 6.6 and 6.9.

“Securities Act” means the Securities Act of 1933, as amended, supplemented or restated from time to time and any successor to such statute.

“Share of Additional Book Basis Derivative Items” means in connection with any allocation of Additional Book Basis Derivative Items for any taxable period, (i) with respect to the Unitholders holding Common Units or Subordinated Units, the amount that bears the same ratio to such Additional Book Basis Derivative Items as the Unitholders’ Remaining Net Positive Adjustments as of the end of such period bears to the Aggregate Remaining Net Positive Adjustments as of that time, (ii) with respect to the General Partner (as holder of the General Partner Interest), the amount that bears the same ratio to such additional Book Basis Derivative Items as the General Partner’s Remaining Net Positive Adjustments as of the end of such period bears to the Aggregate Remaining Net Positive Adjustment as of that time, and (iii) with respect to the Partners holding Incentive Distribution Rights, the amount that bears the same ratio to such Additional Book Basis Derivative Items as the Remaining Net Positive Adjustments of the Partners holding the Incentive Distribution Rights as of the end of such period bears to the Aggregate Remaining Net Positive Adjustments as of that time.

“Special Approval” means approval by a majority of the members of the Conflicts Committee.

“Subordinated Unit” means a Unit representing a fractional part of the Partnership Interests of all Limited Partners and Assignees and having the rights and obligations specified with respect to Subordinated Units in this Agreement. The term “Subordinated Unit” as used herein does not include a Common Unit or Parity Unit. A Subordinated Unit that is convertible into a Common Unit or a Parity Unit shall not constitute a Common Unit or Parity Unit until such conversion occurs.

“Subordination Period” means the period commencing on the Closing Date and ending on the first to occur of the following dates:

(a) the first day of any Quarter beginning after June 30, 2009 in respect of which (i) (A) distributions of Available Cash from Operating Surplus on each of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution (or portion thereof for the first fiscal quarter after

the Closing Date) on all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods and (B) the Adjusted Operating Surplus generated during each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Common Units and Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest, during such periods and (ii) there are no Cumulative Common Unit Arrearages; and

(b) the date on which the General Partner is removed as general partner of the Partnership upon the requisite vote by holders of Outstanding Units under circumstances where Cause does not exist and Units held by the General Partner and its Affiliates are not voted in favor of such removal.

“Subsidiary” means, with respect to any Person, (a) a corporation of which more than 50% of the voting power of shares entitled (without regard to the occurrence of any contingency) to vote in the election of directors or other governing body of such corporation is owned, directly or indirectly, at the date of determination, by such Person, by one or more Subsidiaries of such Person or a combination thereof, (b) a partnership (whether general or limited) in which such Person or a Subsidiary of such Person is, at the date of determination, a general or limited partner of such partnership, but only if more than 50% of the partnership interests of such partnership (considering all of the partnership interests of the partnership as a single class) is owned, directly or indirectly, at the date of determination, by such Person, by one or more Subsidiaries of such Person, or a combination thereof, or (c) any other Person (other than a corporation or a partnership) in which such Person, one or more Subsidiaries of such Person, or a combination thereof, directly or indirectly, at the date of determination, has (i) at least a majority ownership interest or (ii) the power to elect or direct the election of a majority of the directors or other governing body of such Person.

“Substituted Limited Partner” means a Person who is admitted as a Limited Partner to the Partnership pursuant to Section 10.2 in place of and with all the rights of a Limited Partner and who is shown as a Limited Partner on the books and records of the Partnership.

“Surviving Business Entity” has the meaning assigned to such term in Section 14.2(b).

“Third Liquidation Target Amount” has the meaning assigned to such term in Section 6.1(c)(i)(F).

“Third Target Distribution” means $0.375 per Unit per Quarter (or, with respect to the period commencing on the Closing Date and ending on June 30, 2002, it means the product of $0.375 multiplied by a fraction of which the numerator is equal to the number of days in such period and of which the denominator is 91), subject to adjustment in accordance with Sections 6.6 and 6.9.

“Trading Day” has the meaning assigned to such term in Section 15.1(a).

“Transfer” has the meaning assigned to such term in Section 4.4(a).

“Transfer Agent” means such bank, trust company or other Person (including the General Partner or one of its Affiliates) as shall be appointed from time to time by the Partnership to act as registrar and transfer agent for the Common Units; provided that if no Transfer Agent is specifically designated for any other Partnership Securities, the General Partner shall act in such capacity.

“Transfer Application” means an application and agreement for transfer of Units in the form set forth on the back of a Certificate or in a form substantially to the same effect in a separate instrument.

“Underwriter” means each Person named as an underwriter in Schedule I to the Underwriting Agreement who purchases Common Units pursuant thereto.

“Underwriting Agreement” means the Underwriting Agreement dated May 20, 2002 among the Underwriters, the Partnership, the General Partner, the Operating Company and MarkWest Hydrocarbon, Inc., providing for the purchase of Common Units by such Underwriters.

“Unit” means a Partnership Security that is designated as a “Unit” and shall include Common Units and Subordinated Units but shall not include (i) a General Partner Interest or (ii) Incentive Distribution Rights.

“Unit Majority” means, during the Subordination Period, at least a majority of the Outstanding Common Units (excluding Common Units owned by the General Partner and its Affiliates) voting as a class and at least a majority of the Outstanding Subordinated Units voting as a class, and thereafter, at least a majority of the Outstanding Common Units.

“Unit Split” has the meaning assigned to such term in Section 2.1.

“Unitholders” means the holders of Units.

“Unpaid MQD” has the meaning assigned to such term in Section 6.1(c)(i)(B).

“Unrealized Gain” attributable to any item of Partnership property means, as of any date of determination, the excess, if any, of (a) the fair market value of such property as of such date (as determined under Section 5.5(d)) over (b) the Carrying Value of such property as of such date (prior to any adjustment to be made pursuant to Section 5.5(d) as of such date).

“Unrealized Loss” attributable to any item of Partnership property means, as of any date of determination, the excess, if any, of (a) the Carrying Value of such property as of such date

(prior to any adjustment to be made pursuant to Section 5.5(d) as of such date) over (b) the fair market value of such property as of such date (as determined under Section 5.5(d)).

“Unrecovered Capital” means at any time, with respect to a Unit, the Initial Unit Price less the sum of all distributions constituting Capital Surplus theretofore made in respect of an Initial Common Unit and any distributions of cash (or the Net Agreed Value of any distributions in kind) in connection with the dissolution and liquidation of the Partnership theretofore made in respect of an Initial Common Unit, adjusted as the General Partner determines to be appropriate to give effect to any distribution, subdivision or combination of such Units.

“U.S. GAAP” means United States Generally Accepted Accounting Principles consistently applied.

“Withdrawal Opinion of Counsel” has the meaning assigned to such term in Section 11.1(b).

“Working Capital Borrowings” means borrowings used solely for working capital purposes or to pay distributions to Partners made pursuant to a credit facility or other arrangement requiring all such borrowings thereunder to be reduced to a relatively small amount each year (or for the year in which the Initial Offering is consummated, the 12-month period beginning on the Closing Date) for an economically meaningful period of time.

Section 1.2 Construction.

Unless the context requires otherwise: (a) any pronoun used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns, pronouns and verbs shall include the plural and vice versa; (b) references to Articles and Sections refer to Articles and Sections of this Agreement; and (c) the term “include” or “includes” means includes, without limitation, and “including” means including, without limitation.

ARTICLE II

ORGANIZATION

Section 2.1 Formation.

The General Partner and the Organizational Limited Partner have previously formed the Partnership as a limited partnership pursuant to the provisions of the Delaware Act and hereby amend and restate in its entirety the original Agreement of Limited Partnership of MarkWest Energy Partners, L.P. as amended by that certain Amended and Restated Agreement of Limited Partnership of MarkWest Energy Partners, L.P., dated as of May 24, 2002 (“First Amended and Restated Agreement”), as amended by that certain Amendment No. 1, dated December 31, 2004, and Amendment No. 2, dated June 10, 2005, to the First Amended and Restated Agreement. The purpose of this amendment and

restatement is to incorporate the above referenced Amendment Nos. 1 and. 2 to the First Amended and Restated Agreement, and to reflect various numerical changes resulting from the two-for-one split in Common Units and Subordinated Units (the “Unit Split”) declared by the General Partner on January 25, 2007, having a record date of February 22, 2007 and a payment date of January 28, 2007, as well as update the address of the Partnership’s Principal Office. The Unit Split was effected in accordance with Section 5.10, and all such numerical changes are reflected as if the Unit Split had occurred as of May 24, 2002. This amendment and restatement shall become effective on the date of this Agreement. Except as expressly provided to the contrary in this Agreement, the rights, duties (including fiduciary duties), liabilities and obligations of the Partners and the administration, dissolution and termination of the Partnership shall be governed by the Delaware Act. All Partnership Interests shall constitute personal property of the owner thereof for all purposes and a Partner has no interest in specific Partnership property.

Section 2.2 Name.

The name of the Partnership shall be “MarkWest Energy Partners, L.P.” The Partnership’s business may be conducted under any other name or names deemed necessary or appropriate by the General Partner in its sole discretion, including the name of the General Partner. The words “Limited Partnership,” “L.P.,” “Ltd.” or similar words or letters shall be included in the Partnership’s name where necessary for the purpose of complying with the laws of any jurisdiction that so requires. The General Partner in its discretion may change the name of the Partnership at any time and from time to time and shall notify the Limited Partners of such change in the next regular communication to the Limited Partners.

Section 2.3 Registered Office; Registered Agent; Principal Office; Other Offices.

Unless and until changed by the General Partner, the registered office of the Partnership in the State of Delaware shall be located at ▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇, and the registered agent for service of process on the Partnership in the State of Delaware at such registered office shall be The Corporation Trust Company. The principal office of the Partnership shall be located at ▇▇▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇, ▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇ or such other place as the General Partner may from time to time designate by notice to the Limited Partners. The Partnership may maintain offices at such other place or places within or outside the State of Delaware as the General Partner deems necessary or appropriate. The address of the General Partner shall be ▇▇▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, Tower 2, Suite 700, Denver, Colorado 80202 or such other place as the General Partner may from time to time designate by notice to the Limited Partners.

Section 2.4 Purpose and Business.

The purpose and nature of the business to be conducted by the Partnership shall be to (a) serve as a member of the Operating Company and, in connection therewith, to exercise all the rights and powers conferred upon the Partnership as a member of the Operating Company

pursuant to the Operating Company Agreement or otherwise, (b) engage directly in, or enter into or form any corporation, partnership, joint venture, limited liability company or other arrangement to engage indirectly in, any business activity that the Operating Company is permitted to engage in by the Operating Company Agreement or that its subsidiaries are permitted to engage in by their limited liability company or partnership agreements and, in connection therewith, to exercise all of the rights and powers conferred upon the Partnership pursuant to the agreements relating to such business activity, (c) engage directly in, or enter into or form any corporation, partnership, joint venture, limited liability company or other arrangement to engage indirectly in, any business activity that is approved by the General Partner and which lawfully may be conducted by a limited partnership organized pursuant to the Delaware Act and, in connection therewith, to exercise all of the rights and powers conferred upon the Partnership pursuant to the agreements relating to such business activity; provided, however, that the General Partner reasonably determines, as of the date of the acquisition or commencement of such activity, that such activity does not affect the Partnership’s treatment as a partnership for Federal income tax purposes, and (d) do anything necessary or appropriate to the foregoing, including the making of capital contributions or loans to a Group Member. The General Partner has no obligation or duty to the Partnership, the Limited Partners or the Assignees to propose or approve, and in its discretion may decline to propose or approve, the conduct by the Partnership of any business.

Section 2.5 Powers.

The Partnership shall be empowered to do any and all acts and things necessary, appropriate, proper, advisable, incidental to or convenient for the furtherance and accomplishment of the purposes and business described in Section 2.4 and for the protection and benefit of the Partnership.

Section 2.6 Power of Attorney.

(a) Each Limited Partner and each Assignee hereby constitutes and appoints the General Partner and, if a Liquidator shall have been selected pursuant to Section 12.3, the Liquidator (and any successor to the Liquidator by merger, transfer, assignment, election or otherwise) and each of their authorized officers and attorneys-in-fact, as the case may be, with full power of substitution, as his true and lawful agent and attorney-in-fact, with full power and authority in his name, place and ▇▇▇▇▇, to:

(i) execute, swear to, acknowledge, deliver, file and record in the appropriate public offices (A) all certificates, documents and other instruments (including this Agreement and the Certificate of Limited Partnership and all amendments or restatements hereof or thereof) that the General Partner or the Liquidator deems necessary or appropriate to form, qualify or continue the existence or qualification of the Partnership as a limited partnership (or a partnership in which the limited partners have limited liability) in the State of Delaware and in all other jurisdictions in which the Partnership may conduct business or own property; (B) all certificates, documents and other instruments that the General Partner or the Liquidator deems necessary or appropriate to

reflect, in accordance with its terms, any amendment, change, modification or restatement of this Agreement; (C) all certificates, documents and other instruments (including conveyances and a certificate of cancellation) that the General Partner or the Liquidator deems necessary or appropriate to reflect the dissolution and liquidation of the Partnership pursuant to the terms of this Agreement; (D) all certificates, documents and other instruments relating to the admission, withdrawal, removal or substitution of any Partner pursuant to, or other events described in, Article IV, X, XI or XII; (E) all certificates, documents and other instruments relating to the determination of the rights, preferences and privileges of any class or series of Partnership Securities issued pursuant to Section 5.6; and (F) all certificates, documents and other instruments (including agreements and a certificate of merger) relating to a merger or consolidation of the Partnership pursuant to Article XIV; and

(ii) execute, swear to, acknowledge, deliver, file and record all ballots, consents, approvals, waivers, certificates, documents and other instruments necessary or appropriate, in the discretion of the General Partner or the Liquidator, to make, evidence, give, confirm or ratify any vote, consent, approval, agreement or other action that is made or given by the Partners hereunder or is consistent with the terms of this Agreement or is necessary or appropriate, in the discretion of the General Partner or the Liquidator, to effectuate the terms or intent of this Agreement; provided, that when required by Section 13.3 or any other provision of this Agreement that establishes a percentage of the Limited Partners or of the Limited Partners of any class or series required to take any action, the General Partner and the Liquidator may exercise the power of attorney made in this Section 2.6(a)(ii) only after the necessary vote, consent or approval of the Limited Partners or of the Limited Partners of such class or series, as applicable.

Nothing contained in this Section 2.6(a) shall be construed as authorizing the General Partner to amend this Agreement except in accordance with Article XIII or as may be otherwise expressly provided for in this Agreement.

(b) The foregoing power of attorney is hereby declared to be irrevocable and a power coupled with an interest, and it shall survive and, to the maximum extent permitted by law, not be affected by the subsequent death, incompetency, disability, incapacity, dissolution, bankruptcy or termination of any Limited Partner or Assignee and the transfer of all or any portion of such Limited Partner’s or Assignee’s Partnership Interest and shall extend to such Limited Partner’s or Assignee’s heirs, successors, assigns and personal representatives. Each such Limited Partner or Assignee hereby agrees to be bound by any representation made by the General Partner or the Liquidator acting in good faith pursuant to such power of attorney; and each such Limited Partner or Assignee, to the maximum extent permitted by law, hereby waives any and all defenses that may be available to contest, negate or disaffirm the action of the General Partner or the Liquidator taken in good faith under such power of attorney. Each Limited Partner or Assignee shall execute and deliver to the General Partner or the Liquidator, within 15 days after receipt of the request therefor, such further designation, powers of attorney and other instruments as the General Partner or the Liquidator deems necessary to effectuate this Agreement and the purposes of the Partnership.

Section 2.7 Term.

The term of the Partnership commenced upon the filing of the Certificate of Limited Partnership in accordance with the Delaware Act and shall continue in existence until the dissolution of the Partnership in accordance with the provisions of Article XII. The existence of the Partnership as a separate legal entity shall continue until the cancellation of the Certificate of Limited Partnership as provided in the Delaware Act.

Section 2.8 Title to Partnership Assets.

Title to Partnership assets, whether real, personal or mixed and whether tangible or intangible, shall be deemed to be owned by the Partnership as an entity, and no Partner or Assignee, individually or collectively, shall have any ownership interest in such Partnership assets or any portion thereof. Title to any or all of the Partnership assets may be held in the name of the Partnership, the General Partner, one or more of its Affiliates or one or more nominees, as the General Partner may determine. The General Partner hereby declares and warrants that any Partnership assets for which record title is held in the name of the General Partner or one or more of its Affiliates or one or more nominees shall be held by the General Partner or such Affiliate or nominee for the use and benefit of the Partnership in accordance with the provisions of this Agreement; provided, however, that the General Partner shall use reasonable efforts to cause record title to such assets (other than those assets in respect of which the General Partner determines that the expense and difficulty of conveyancing makes transfer of record title to the Partnership impracticable) to be vested in the Partnership as soon as reasonably practicable; provided, further, that, prior to the withdrawal or removal of the General Partner or as soon thereafter as practicable, the General Partner shall use reasonable efforts to effect the transfer of record title to the Partnership and, prior to any such transfer, will provide for the use of such assets in a manner satisfactory to the General Partner. All Partnership assets shall be recorded as the property of the Partnership in its books and records, irrespective of the name in which record title to such Partnership assets is held.

ARTICLE III

RIGHTS OF LIMITED PARTNERS

Section 3.1 Limitation of Liability.

The Limited Partners and the Assignees shall have no liability under this Agreement except as expressly provided in this Agreement or the Delaware Act.

Section 3.2 Management of Business.

No Limited Partner or Assignee, in its capacity as such, shall participate in the operation, management or control (within the meaning of the Delaware Act) of the Partnership’s business, transact any business in the Partnership’s name or have the power to sign documents for or otherwise bind the Partnership. Any action taken by any Affiliate of the General Partner or any

officer, director, employee, manager, member, general partner, agent or trustee of the General Partner or any of its Affiliates, or any officer, director, employee, member, general partner, agent or trustee of a Group Member, in its capacity as such, shall not be deemed to be participation in the control of the business of the Partnership by a limited partner of the Partnership (within the meaning of Section 17-303(a) of the Delaware Act) and shall not affect, impair or eliminate the limitations on the liability of the Limited Partners or Assignees under this Agreement.

Section 3.3 Outside Activities of the Limited Partners.

Subject to the provisions of Section 7.5 and the Omnibus Agreement, which shall continue to be applicable to the Persons referred to therein, regardless of whether such Persons shall also be Limited Partners or Assignees, any Limited Partner or Assignee shall be entitled to and may have business interests and engage in business activities in addition to those relating to the Partnership, including business interests and activities in direct competition with the Partnership Group. Neither the Partnership nor any of the other Partners or Assignees shall have any rights by virtue of this Agreement in any business ventures of any Limited Partner or Assignee.

Section 3.4 Rights of Limited Partners.

(a) In addition to other rights provided by this Agreement or by applicable law, and except as limited by Section 3.4(b), each Limited Partner shall have the right, for a purpose reasonably related to such Limited Partner’s interest as a limited partner in the Partnership, upon reasonable written demand and at such Limited Partner’s own expense:

(i) to obtain true and full information regarding the status of the business and financial condition of the Partnership;

(ii) promptly after becoming available, to obtain a copy of the Partnership’s federal, state and local income tax returns for each year;

(iii) to have furnished to him a current list of the name and last known business, residence or mailing address of each Partner;

(iv) to have furnished to him a copy of this Agreement and the Certificate of Limited Partnership and all amendments thereto, together with a copy of the executed copies of all powers of attorney pursuant to which this Agreement, the Certificate of Limited Partnership and all amendments thereto have been executed;

(v) to obtain true and full information regarding the amount of cash and a description and statement of the Net Agreed Value of any other Capital Contribution by each Partner and which each Partner has agreed to contribute in the future, and the date on which each became a Partner; and

(vi) to obtain such other information regarding the affairs of the Partnership as is just and reasonable.

(b) The General Partner may keep confidential from the Limited Partners and Assignees, for such period of time as the General Partner deems reasonable, (i) any information that the General Partner reasonably believes to be in the nature of trade secrets or (ii) other information the disclosure of which the General Partner in good faith believes (A) is not in the best interests of the Partnership Group, (B) could damage the Partnership Group or (C) that any Group Member is required by law or by agreement with any third party to keep confidential (other than agreements with Affiliates of the Partnership the primary purpose of which is to circumvent the obligations set forth in this Section 3.4).

ARTICLE IV

CERTIFICATES; RECORD HOLDERS; TRANSFER OF PARTNERSHIP INTERESTS;
REDEMPTION OF PARTNERSHIP INTERESTS

Section 4.1 Certificates.

Upon the Partnership’s issuance of Common Units or Subordinated Units to any Person, the Partnership shall issue one or more Certificates in the name of such Person evidencing the number of such Units being so issued. In addition, (a) upon the General Partner’s request, the Partnership shall issue to it one or more Certificates in the name of the General Partner evidencing its interests in the Partnership and (b) upon the request of any Person owning Incentive Distribution Rights or any other Partnership Securities other than Common Units or Subordinated Units, the Partnership shall issue to such Person one or more certificates evidencing such Incentive Distribution Rights or other Partnership Securities other than Common Units or Subordinated Units. Certificates shall be executed on behalf of the Partnership by the Chairman of the Board, President or any Executive Vice President or Vice President and the Secretary or any Assistant Secretary of the General Partner. No Common Unit Certificate shall be valid for any purpose until it has been countersigned by the Transfer Agent; provided, however, that if the General Partner elects to issue Common Units in global form, the Common Unit Certificates shall be valid upon receipt of a certificate from the Transfer Agent certifying that the Common Units have been duly registered in accordance with the directions of the Partnership and the Underwriters. Subject to the requirements of Section 6.7(b), the Partners holding Certificates evidencing Subordinated Units may exchange such Certificates for Certificates evidencing Common Units on or after the date on which such Subordinated Units are converted into Common Units pursuant to the terms of Section 5.8.

Section 4.2 Mutilated, Destroyed, Lost or Stolen Certificates.

(a) If any mutilated Certificate is surrendered to the Transfer Agent, the appropriate officers of the General Partner on behalf of the Partnership shall execute, and the Transfer Agent shall countersign and deliver in exchange therefor, a new Certificate evidencing the same number and type of Partnership Securities as the Certificate so surrendered.

(b) The appropriate officers of the General Partner on behalf of the Partnership shall execute and deliver, and the Transfer Agent shall countersign, a new Certificate in place of any Certificate previously issued if the Record Holder of the Certificate:

(i) makes proof by affidavit, in form and substance satisfactory to the General Partner, that a previously issued Certificate has been lost, destroyed or stolen;

(ii) requests the issuance of a new Certificate before the General Partner has notice that the Certificate has been acquired by a purchaser for value in good faith and without notice of an adverse claim;

(iii) if requested by the General Partner, delivers to the General Partner a bond, in form and substance satisfactory to the General Partner, with surety or sureties and with fixed or open penalty as the General Partner may reasonably direct, in its sole discretion, to indemnify the Partnership, the Partners, the General Partner and the Transfer Agent against any claim that may be made on account of the alleged loss, destruction or theft of the Certificate; and

(iv) satisfies any other reasonable requirements imposed by the General Partner.

If a Limited Partner or Assignee fails to notify the General Partner within a reasonable time after he has notice of the loss, destruction or theft of a Certificate, and a transfer of the Limited Partner Interests represented by the Certificate is registered before the Partnership, the General Partner or the Transfer Agent receives such notification, the Limited Partner or Assignee shall be precluded from making any claim against the Partnership, the General Partner or the Transfer Agent for such transfer or for a new Certificate.

(c) As a condition to the issuance of any new Certificate under this Section 4.2, the General Partner may require the payment of a sum sufficient to cover any tax or other governmental charge that may be imposed in relation thereto and any other expenses (including the fees and expenses of the Transfer Agent) reasonably connected therewith.

Section 4.3 Record Holders.

The Partnership shall be entitled to recognize the Record Holder as the Partner or Assignee with respect to any Partnership Interest and, accordingly, shall not be bound to recognize any equitable or other claim to or interest in such Partnership Interest on the part of any other Person, regardless of whether the Partnership shall have actual or other notice thereof, except as otherwise provided by law or any applicable rule, regulation, guideline or requirement of any National Securities Exchange on which such Partnership Interests are listed for trading. Without limiting the foregoing, when a Person (such as a broker, dealer, bank, trust company or clearing corporation or an agent of any of the foregoing) is acting as nominee, agent or in some other representative capacity for another Person in acquiring and/or holding Partnership Interests, as between the Partnership on the one hand, and such other Persons on the other, such

representative Person (a) shall be the Partner or Assignee (as the case may be) of record and beneficially, (b) must execute and deliver a Transfer Application and (c) shall be bound by this Agreement and shall have the rights and obligations of a Partner or Assignee (as the case may be) hereunder and as, and to the extent, provided for herein.

Section 4.4 Transfer Generally.

(a) The term “transfer,” when used in this Agreement with respect to a Partnership Interest, shall be deemed to refer to a transaction by which the General Partner assigns its General Partner Interest to another Person who becomes the general partner of the Partnership, by which the holder of a Limited Partner Interest assigns such Limited Partner Interest to another Person who is or becomes a Limited Partner or an Assignee, and includes a sale, assignment, gift, pledge, encumbrance, hypothecation, mortgage, exchange or any other disposition by law or otherwise.

(b) No Partnership Interest shall be transferred, in whole or in part, except in accordance with the terms and conditions set forth in this Article IV. Any transfer or purported transfer of a Partnership Interest not made in accordance with this Article IV shall be null and void.

(c) Nothing contained in this Agreement shall be construed to prevent a disposition by any member of the General Partner of any or all of the membership interests of the General Partner.

Section 4.5 Registration and Transfer of Limited Partner Interests.

(a) The General Partner shall keep or cause to be kept on behalf of the Partnership a register in which, subject to such reasonable regulations as it may prescribe and subject to the provisions of Section 4.5(b), the Partnership will provide for the registration and transfer of Limited Partner Interests. The Transfer Agent is hereby appointed registrar and transfer agent for the purpose of registering Common Units and transfers of such Common Units as herein provided. The Partnership shall not recognize transfers of Certificates evidencing Limited Partner Interests unless such transfers are effected in the manner described in this Section 4.5. Upon surrender of a Certificate for registration of transfer of any Limited Partner Interests evidenced by a Certificate, and subject to the provisions of Section 4.5(b), the appropriate officers of the General Partner on behalf of the Partnership shall execute and deliver, and in the case of Common Units, the Transfer Agent shall countersign and deliver, in the name of the holder or the designated transferee or transferees, as required pursuant to the holder’s instructions, one or more new Certificates evidencing the same aggregate number and type of Limited Partner Interests as was evidenced by the Certificate so surrendered.

(b) Except as otherwise provided in Section 4.9, the General Partner shall not recognize any transfer of Limited Partner Interests until the Certificates evidencing such Limited Partner Interests are surrendered for registration of transfer and such Certificates are accompanied by a Transfer Application duly executed by the transferee (or the transferee’s

attorney-in-fact duly authorized in writing). No charge shall be imposed by the General Partner for such transfer; provided, that as a condition to the issuance of any new Certificate under this Section 4.5, the General Partner may require the payment of a sum sufficient to cover any tax or other governmental charge that may be imposed with respect thereto.

(c) Limited Partner Interests may be transferred only in the manner described in this Section 4.5. The transfer of any Limited Partner Interests and the admission of any new Limited Partner shall not constitute an amendment to this Agreement.

(d) Until admitted as a Substituted Limited Partner pursuant to Section 10.2, the Record Holder of a Limited Partner Interest shall be an Assignee in respect of such Limited Partner Interest. Limited Partners may include custodians, nominees or any other individual or entity in its own or any representative capacity.

(e) A transferee of a Limited Partner Interest who has completed and delivered a Transfer Application shall be deemed to have (i) requested admission as a Substituted Limited Partner, (ii) agreed to comply with and be bound by and to have executed this Agreement, (iii) represented and warranted that such transferee has the right, power and authority and, if an individual, the capacity to enter into this Agreement, (iv) granted the powers of attorney set forth in this Agreement and (v) given the consents and approvals and made the waivers contained in this Agreement.

(f) The General Partner and its Affiliates shall have the right at any time to transfer their Subordinated Units and Common Units (whether issued upon conversion of the Subordinated Units or otherwise) to one or more Persons.

Section 4.6 Transfer of the General Partner’s General Partner Interest.

(a) Subject to Section 4.6(c) below, prior to June 30, 2012, the General Partner shall not transfer all or any part of its General Partner Interest to a Person unless such transfer (i) has been approved by the prior written consent or vote of the holders of at least a majority of the Outstanding Common Units (excluding Common Units held by the General Partner and its Affiliates) or (ii) is of all, but not less than all, of its General Partner Interest to (A) an Affiliate of the General Partner (other than an individual) or (B) another Person (other than an individual) in connection with the merger or consolidation of the General Partner with or into another Person (other than an individual) or the transfer by the General Partner of all or substantially all of its assets to another Person (other than an individual).

(b) Subject to Section 4.6(c) below, on or after June 30, 2012, the General Partner may transfer all or any of its General Partner Interest without Unitholder approval.

(c) Notwithstanding anything herein to the contrary, no transfer by the General Partner of all or any part of its General Partner Interest to another Person shall be permitted unless (i) the transferee agrees to assume the rights and duties of the General Partner under this Agreement and to be bound by the provisions of this Agreement, (ii) the Partnership receives an

Opinion of Counsel that such transfer would not result in the loss of limited liability of any Limited Partner or of any member of the Operating Company or cause the Partnership or the Operating Company to be treated as an association taxable as a corporation or otherwise to be taxed as an entity for federal income tax purposes (to the extent not already so treated or taxed) and (iii) such transferee also agrees to purchase all (or the appropriate portion thereof, if applicable) of the partnership or membership interest of the General Partner as the general partner or managing member, if any, of each other Group Member. In the case of a transfer pursuant to and in compliance with this Section 4.6, the transferee or successor (as the case may be) shall, subject to compliance with the terms of Section 10.3, be admitted to the Partnership as the General Partner immediately prior to the transfer of the Partnership Interest, and the business of the Partnership shall continue without dissolution.

Section 4.7 Transfer of Incentive Distribution Rights.

Prior to June 30, 2012, a holder of Incentive Distribution Rights may transfer any or all of the Incentive Distribution Rights held by such holder without any consent of the Unitholders (a) to an Affiliate of such holder (other than an individual) or (b) to another Person (other than an individual) in connection with (i) the merger or consolidation of such holder of Incentive Distribution Rights with or into such other Person, (ii) the transfer by such holder of all or substantially all of its assets to such other Person or (iii) the sale of all or substantially all its equity interests to such other Person. Any other transfer of the Incentive Distribution Rights prior to June 30, 2012, shall require the prior approval of holders of at least a majority of the Outstanding Common Units (excluding Common Units held by the General Partner and its Affiliates). On or after June 30, 2012, the General Partner or any other holder of Incentive Distribution Rights may transfer any or all of its Incentive Distribution Rights without Unitholder approval. Notwithstanding anything herein to the contrary, no transfer of Incentive Distribution Rights to another Person shall be permitted unless the transferee agrees to be bound by the provisions of this Agreement.

Section 4.8 Restrictions on Transfers.

(a) Except as provided in Section 4.8(d) below, but notwithstanding the other provisions of this Article IV, no transfer of any Partnership Interests shall be made if such transfer would (i) violate the then applicable federal or state securities laws or rules and regulations of the Commission, any state securities commission or any other governmental authority with jurisdiction over such transfer, (ii) terminate the existence or qualification of the Partnership or the Operating Company under the laws of the jurisdiction of its formation, or (iii) cause the Partnership or the Operating Company to be treated as an association taxable as a corporation or otherwise to be taxed as an entity for federal income tax purposes (to the extent not already so treated or taxed).

(b) The General Partner may impose restrictions on the transfer of Partnership Interests if a subsequent Opinion of Counsel determines that such restrictions are necessary to avoid a significant risk of any Group Member becoming taxable as a corporation or otherwise to be taxed as an entity for federal income tax purposes. The restrictions may be imposed by

making such amendments to this Agreement as the General Partner may determine to be necessary or appropriate to impose such restrictions; provided, however, that any amendment that the General Partner believes, in the exercise of its reasonable discretion, could result in the delisting or suspension of trading of any class of Limited Partner Interests on the principal National Securities Exchange on which such class of Limited Partner Interests is then traded must be approved, prior to such amendment being effected, by the holders of at least a majority of the Outstanding Limited Partner Interests of such class.

(c) The transfer of a Subordinated Unit that has converted into a Common Unit shall be subject to the restrictions imposed by Section 6.7(b).

(d) Nothing contained in this Article IV, or elsewhere in this Agreement, shall preclude the settlement of any transactions involving Partnership Interests entered into through the facilities of any National Securities Exchange on which such Partnership Interests are listed for trading.

Section 4.9 Citizenship Certificates; Non-citizen Assignees.

(a) If any Group Member is or becomes subject to any federal, state or local law or regulation that, in the reasonable determination of the General Partner, creates a substantial risk of cancellation or forfeiture of any property in which the Group Member has an interest based on the nationality, citizenship or other related status of a Limited Partner or Assignee, the General Partner may request any Limited Partner or Assignee to furnish to the General Partner, within 30 days after receipt of such request, an executed Citizenship Certification or such other information concerning his nationality, citizenship or other related status (or, if the Limited Partner or Assignee is a nominee holding for the account of another Person, the nationality, citizenship or other related status of such Person) as the General Partner may request. If a Limited Partner or Assignee fails to furnish to the General Partner within the aforementioned 30-day period such Citizenship Certification or other requested information or if upon receipt of such Citizenship Certification or other requested information the General Partner determines, with the advice of counsel, that a Limited Partner or Assignee is not an Eligible Citizen, the Partnership Interests owned by such Limited Partner or Assignee shall be subject to redemption in accordance with the provisions of Section 4.10. In addition, the General Partner may require that the status of any such Partner or Assignee be changed to that of a Non-citizen Assignee and, thereupon, the General Partner shall be substituted for such Non-citizen Assignee as the Limited Partner in respect of his Limited Partner Interests.

(b) The General Partner shall, in exercising voting rights in respect of Limited Partner Interests held by it on behalf of Non-citizen Assignees, distribute the votes in the same ratios as the votes of Partners (including without limitation the General Partner) in respect of Limited Partner Interests other than those of Non-citizen Assignees are cast, either for, against or abstaining as to the matter.

(c) Upon dissolution of the Partnership, a Non-citizen Assignee shall have no right to receive a distribution in kind pursuant to Section 12.4 but shall be entitled to the cash equivalent

thereof, and the Partnership shall provide cash in exchange for an assignment of the Non-citizen Assignee’s share of the distribution in kind. Such payment and assignment shall be treated for Partnership purposes as a purchase by the Partnership from the Non-citizen Assignee of his Limited Partner Interest (representing his right to receive his share of such distribution in kind).

(d) At any time after he can and does certify that he has become an Eligible Citizen, a Non-citizen Assignee may, upon application to the General Partner, request admission as a Substituted Limited Partner with respect to any Limited Partner Interests of such Non-citizen Assignee not redeemed pursuant to Section 4.10, and upon his admission pursuant to Section 10.2, the General Partner shall cease to be deemed to be the Limited Partner in respect of the Non-citizen Assignee’s Limited Partner Interests.

Section 4.10 Redemption of Partnership Interests of Non-citizen Assignees.

(a) If at any time a Limited Partner or Assignee fails to furnish a Citizenship Certification or other information requested within the 30-day period specified in Section 4.9(a), or if upon receipt of such Citizenship Certification or other information the General Partner determines, with the advice of counsel, that a Limited Partner or Assignee is not an Eligible Citizen, the Partnership may, unless the Limited Partner or Assignee establishes to the satisfaction of the General Partner that such Limited Partner or Assignee is an Eligible Citizen or has transferred his Partnership Interests to a Person who is an Eligible Citizen and who furnishes a Citizenship Certification to the General Partner prior to the date fixed for redemption as provided below, redeem the Partnership Interest of such Limited Partner or Assignee as follows:

(i) The General Partner shall, not later than the 30th day before the date fixed for redemption, give notice of redemption to the Limited Partner or Assignee, at his last address designated on the records of the Partnership or the Transfer Agent, by registered or certified mail, postage prepaid. The notice shall be deemed to have been given when so mailed. The notice shall specify the Redeemable Interests, the date fixed for redemption, the place of payment, that payment of the redemption price will be made upon surrender of the Certificate evidencing the Redeemable Interests and that on and after the date fixed for redemption no further allocations or distributions to which the Limited Partner or Assignee would otherwise be entitled in respect of the Redeemable Interests will accrue or be made.

(ii) The aggregate redemption price for Redeemable Interests shall be an amount equal to the Current Market Price (the date of determination of which shall be the date fixed for redemption) of Limited Partner Interests of the class to be so redeemed multiplied by the number of Limited Partner Interests of each such class included among the Redeemable Interests. The redemption price shall be paid, in the discretion of the General Partner, in cash or by delivery of a promissory note of the Partnership in the principal amount of the redemption price, bearing interest at the rate of 10% annually and payable in three equal annual installments of principal together with accrued interest, commencing one year after the redemption date.

(iii) Upon surrender by or on behalf of the Limited Partner or Assignee, at the place specified in the notice of redemption, of the Certificate evidencing the Redeemable Interests, duly endorsed in blank or accompanied by an assignment duly executed in blank, the Limited Partner or Assignee or his duly authorized representative shall be entitled to receive the payment therefor.

(iv) After the redemption date, Redeemable Interests shall no longer constitute issued and Outstanding Limited Partner Interests.

(b) The provisions of this Section 4.10 shall also be applicable to Limited Partner Interests held by a Limited Partner or Assignee as nominee of a Person determined to be other than an Eligible Citizen.

(c) Nothing in this Section 4.10 shall prevent the recipient of a notice of redemption from transferring his Limited Partner Interest before the redemption date if such transfer is otherwise permitted under this Agreement. Upon receipt of notice of such a transfer, the General Partner shall withdraw the notice of redemption, provided the transferee of such Limited Partner Interest certifies to the satisfaction of the General Partner in a Citizenship Certification delivered in connection with the Transfer Application that he is an Eligible Citizen. If the transferee fails to make such certification, such redemption shall be effected from the transferee on the original redemption date.

ARTICLE V

CAPITAL CONTRIBUTIONS AND ISSUANCE OF PARTNERSHIP INTERESTS

Section 5.1 Organizational Contributions.

In connection with the formation of the Partnership under the Delaware Act, the General Partner made an initial Capital Contribution to the Partnership in the amount of $20.00, for a 2% General Partner interest in the Partnership and has been admitted as the General Partner of the Partnership, and the Organizational Limited Partner made an initial Capital Contribution to the Partnership in the amount of $980.00 for a 98% Limited Partner interest in the Partnership and has been admitted as a Limited Partner of the Partnership. As of the Closing Date, the interest of the Organizational Limited Partner shall be redeemed as provided in the Contribution Agreement; the initial Capital Contributions of the Organizational Limited Partner shall thereupon be refunded; and the Organizational Limited Partner shall cease to be a Limited Partner of the Partnership. Ninety-eight percent of any interest or other profit that may have resulted from the investment or other use of such initial Capital Contributions shall be allocated and distributed to the Organizational Limited Partner, and the balance thereof shall be allocated and distributed to the General Partner.

Section 5.2 Contributions by the General Partner and its Affiliates.

(a) On the Closing Date and pursuant to the Contribution Agreement, (i) the General Partner shall contribute to the Partnership, as a Capital Contribution, all of its ownership interests in MarkWest Energy Appalachia, L.L.C. in exchange for (A) the continuation of its 2% General Partner Interest, subject to all of the rights, privileges and duties of the General Partner under this Agreement, (B) the Incentive Distribution Rights, (C) 3,554,000 Subordinated Units, (D) the right to receive $25.8 million from the Partnership on the Closing Date sourced to new debt and (E) the right to be reimbursed for $16.1 million in capital expenditures and (ii) MarkWest Michigan, Inc. shall contribute to the Partnership, as a Capital Contribution, all of its interest in Basin Pipeline L.L.C. and West Shore Processing Company, L.L.C. in exchange for (A) 2,446,000 Subordinated Units, (B) the assumption by the Partnership of $15.1 million in debt and (C) the right to be reimbursed for $0.4 million in capital expenditures.

(b) Upon the issuance of any additional Limited Partner Interests by the Partnership (other than the issuance of the Common Units issued in the Initial Offering and other than the issuance of the Common Units issued pursuant to the Over-Allotment Option), the General Partner shall be required to make additional Capital Contributions equal to 2/98ths of any amount contributed to the Partnership by the Limited Partners in exchange for the additional Limited Partner Interests issued to such Limited Partners. Except as set forth in the immediately preceding sentence and Article XII, the General Partner shall not be obligated to make any additional Capital Contributions to the Partnership.

(c) The General Partners shall contribute $1,600,000 as required by the Partnership to fund the construction and completion of the New ▇▇▇▇ Plant.

Section 5.3 Contributions by Initial Limited Partners and Distributions to the General Partner and its Affiliates.

(a) On the Closing Date and pursuant to the Underwriting Agreement, each Underwriter shall contribute to the Partnership cash in an amount equal to the Issue Price per Initial Common Unit, multiplied by the number of Common Units specified in the Underwriting Agreement to be purchased by such Underwriter at the Closing Date. In exchange for such Capital Contributions by the Underwriters, the Partnership shall issue Common Units to each Underwriter on whose behalf such Capital Contribution is made in an amount equal to the quotient obtained by dividing (i) the cash contribution to the Partnership by or on behalf of such Underwriter by (ii) the Issue Price per Initial Common Unit.

(b) Upon the exercise of the Over-Allotment Option, each Underwriter shall contribute to the Partnership cash in an amount equal to the Issue Price per Initial Common Unit, multiplied by the number of Common Units specified in the Underwriting Agreement to be purchased by such Underwriter at the Option Closing Date. In exchange for such Capital Contributions by the Underwriters, the Partnership shall issue Common Units to each Underwriter on whose behalf such Capital Contribution is made in an amount equal to the

quotient obtained by dividing (i) the cash contributions to the Partnership by or on behalf of such Underwriter by (ii) the Issue Price per Initial Common Unit.

(c) No Limited Partner Interests will be issued or issuable as of or at the Closing Date other than (i) the Common Units issuable pursuant to subparagraph (a) hereof in aggregate number equal to 4,200,000, (ii) the “Additional Units” as such term is used in the Underwriting Agreement in an aggregate number up to 630,000 issuable upon exercise of the Over-Allotment Option pursuant to subparagraph (b) hereof, (iii) the 6,000,000 Subordinated Units issuable to MarkWest Michigan, Inc. and the General Partner pursuant to Section 5.2 hereof, and (iv) the Incentive Distribution Rights.

Section 5.4 Interest and Withdrawal.

No interest shall be paid by the Partnership on Capital Contributions. No Partner or Assignee shall be entitled to the withdrawal or return of its Capital Contribution, except to the extent, if any, that distributions made pursuant to this Agreement or upon termination of the Partnership may be considered as such by law and then only to the extent provided for in this Agreement. Except to the extent expressly provided in this Agreement, no Partner or Assignee shall have priority over any other Partner or Assignee either as to the return of Capital Contributions or as to profits, losses or distributions. Any such return shall be a compromise to which all Partners and Assignees agree within the meaning of 17-502(b) of the Delaware Act.

Section 5.5 Capital Accounts.

(a) The Partnership shall maintain for each Partner (or a beneficial owner of Partnership Interests held by a nominee in any case in which the nominee has furnished the identity of such owner to the Partnership in accordance with Section 6031(c) of the Code or any other method acceptable to the General Partner in its sole discretion) owning a Partnership Interest a separate Capital Account with respect to such Partnership Interest in accordance with the rules of Treasury Regulation Section 1.704-1(b)(2)(iv). Such Capital Account shall be increased by (i) the amount of all Capital Contributions made to the Partnership with respect to such Partnership Interest pursuant to this Agreement and (ii) all items of Partnership income and gain (including, without limitation, income and gain exempt from tax) computed in accordance with Section 5.5(b) and allocated with respect to such Partnership Interest pursuant to Section 6.1, and decreased by (x) the amount of cash or Net Agreed Value of all actual and deemed distributions of cash or property made with respect to such Partnership Interest pursuant to this Agreement and (y) all items of Partnership deduction and loss computed in accordance with Section 5.5(b) and allocated with respect to such Partnership Interest pursuant to Section 6.1.

(b) For purposes of computing the amount of any item of income, gain, loss or deduction which is to be allocated pursuant to Article VI and is to be reflected in the Partners’ Capital Accounts, the determination, recognition and classification of any such item shall be the same as its determination, recognition and classification for federal income tax purposes (including, without limitation, any method of depreciation, cost recovery or amortization used for that purpose), provided, that:

(i) Solely for purposes of this Section 5.5, the Partnership shall be treated as owning directly its proportionate share (as determined by the General Partner based upon the provisions of the Operating Company Agreement) of all property owned by the Operating Company or any other Subsidiary that is classified as a partnership for federal income tax purposes.

(ii) All fees and other expenses incurred by the Partnership to promote the sale of (or to sell) a Partnership Interest that can neither be deducted nor amortized under Section 709 of the Code, if any, shall, for purposes of Capital Account maintenance, be treated as an item of deduction at the time such fees and other expenses are incurred and shall be allocated among the Partners pursuant to Section 6.1.

(iii) Except as otherwise provided in Treasury Regulation Section 1.704-1(b)(2)(iv)(m), the computation of all items of income, gain, loss and deduction shall be made without regard to any election under Section 754 of the Code which may be made by the Partnership and, as to those items described in Section 705(a)(1)(B) or 705(a)(2)(B) of the Code, without regard to the fact that such items are not includable in gross income or are neither currently deductible nor capitalized for federal income tax purposes. To the extent an adjustment to the adjusted tax basis of any Partnership asset pursuant to Section 734(b) or 743(b) of the Code is required, pursuant to Treasury Regulation Section 1.704-1(b)(2)(iv)(m), to be taken into account in determining Capital Accounts, the amount of such adjustment in the Capital Accounts shall be treated as an item of gain or loss.

(iv) Any income, gain or loss attributable to the taxable disposition of any Partnership property shall be determined as if the adjusted basis of such property as of such date of disposition were equal in amount to the Partnership’s Carrying Value with respect to such property as of such date.

(v) In accordance with the requirements of Section 704(b) of the Code, any deductions for depreciation, cost recovery or amortization attributable to any Contributed Property shall be determined as if the adjusted basis of such property on the date it was acquired by the Partnership were equal to the Agreed Value of such property. Upon an adjustment pursuant to Section 5.5(d) to the Carrying Value of any Partnership property subject to depreciation, cost recovery or amortization, any further deductions for such depreciation, cost recovery or amortization attributable to such property shall be determined (A) as if the adjusted basis of such property were equal to the Carrying Value of such property immediately following such adjustment and (B) using a rate of depreciation, cost recovery or amortization derived from the same method and useful life (or, if applicable, the remaining useful life) as is applied for federal income tax purposes; provided, however, that, if the asset has a zero adjusted basis for federal income tax purposes, depreciation, cost recovery or amortization deductions shall be determined using any reasonable method that the General Partner may adopt.

(vi) If the Partnership’s adjusted basis in a depreciable or cost recovery property is reduced for federal income tax purposes pursuant to Section 48(q)(1) or 48(q)(3) of the Code, the amount of such reduction shall, solely for purposes hereof, be deemed to be an additional depreciation or cost recovery deduction in the year such property is placed in service and shall be allocated among the Partners pursuant to Section 6.1. Any restoration of such basis pursuant to Section 48(q)(2) of the Code shall, to the extent possible, be allocated in the same manner to the Partners to whom such deemed deduction was allocated.

(c) (i) A transferee of a Partnership Interest shall succeed to a pro rata portion of the Capital Account of the transferor relating to the Partnership Interest so transferred.

(ii) Immediately prior to the transfer of a Subordinated Unit or of a Subordinated Unit that has converted into a Common Unit pursuant to Section 5.8 by a holder thereof (other than a transfer to an Affiliate unless the General Partner elects to have this subparagraph 5.5(c)(ii) apply), the Capital Account maintained for such Person with respect to its Subordinated Units or converted Subordinated Units will (A) first, be allocated to the Subordinated Units or converted Subordinated Units to be transferred in an amount equal to the product of (x) the number of such Subordinated Units or converted Subordinated Units to be transferred and (y) the Per Unit Capital Amount for a Common Unit, and (B) second, any remaining balance in such Capital Account will be retained by the transferor, regardless of whether it has retained any Subordinated Units or converted Subordinated Units. Following any such allocation, the transferor’s Capital Account, if any, maintained with respect to the retained Subordinated Units or converted Subordinated Units, if any, will have a balance equal to the amount allocated under clause (B) hereinabove, and the transferee’s Capital Account established with respect to the transferred Subordinated Units or converted Subordinated Units will have a balance equal to the amount allocated under clause (A) hereinabove.

(d) (i) In accordance with Treasury Regulation Section 1.704-1(b)(2)(iv)(f), on an issuance of additional Partnership Interests for cash or Contributed Property or the conversion of the General Partner’s Combined Interest to Common Units pursuant to Section 11.3(b), the Capital Account of all Partners and the Carrying Value of each Partnership property immediately prior to such issuance shall be adjusted upward or downward to reflect any Unrealized Gain or Unrealized Loss attributable to such Partnership property, as if such Unrealized Gain or Unrealized Loss had been recognized on an actual sale of each such property immediately prior to such issuance and had been allocated to the Partners at such time pursuant to Section 6.1 in the same manner as any item of gain or loss actually recognized during such period would have been allocated. In determining such Unrealized Gain or Unrealized Loss, the aggregate cash amount and fair market value of all Partnership assets (including, without limitation, cash or cash equivalents) immediately prior to the issuance of additional Partnership Interests shall be determined by the General Partner using such reasonable method of valuation as it may adopt; provided, however, that the General Partner, in arriving at such valuation, must take fully into account the fair market value of the Partnership Interests of all Partners at such time. The General Partner shall allocate such aggregate value among the assets of the Partnership (in such

manner as it determines in its discretion to be reasonable) to arrive at a fair market value for individual properties.

(ii) In accordance with Treasury Regulation Section 1.704-1(b)(2)(iv)(f), immediately prior to any actual or deemed distribution to a Partner of any Partnership property (other than a distribution of cash that is not in redemption or retirement of a Partnership Interest), the Capital Accounts of all Partners and the Carrying Value of all Partnership property shall be adjusted upward or downward to reflect any Unrealized Gain or Unrealized Loss attributable to such Partnership property, as if such Unrealized Gain or Unrealized Loss had been recognized in a sale of such property immediately prior to such distribution for an amount equal to its fair market value, and had been allocated to the Partners, at such time, pursuant to Section 6.1 in the same manner as any item of gain or loss actually recognized during such period would have been allocated. In determining such Unrealized Gain or Unrealized Loss the aggregate cash amount and fair market value of all Partnership assets (including, without limitation, cash or cash equivalents) immediately prior to a distribution shall (A) in the case of an actual distribution which is not made pursuant to Section 12.4 or in the case of a deemed distribution, be determined and allocated in the same manner as that provided in Section 5.5(d)(i) or (B) in the case of a liquidating distribution pursuant to Section 12.4, be determined and allocated by the Liquidator using such reasonable method of valuation as it may adopt.

Section 5.6 Issuances of Additional Partnership Securities.

(a) Subject to Section 5.7, the Partnership may issue additional Partnership Securities and options, rights, warrants and appreciation rights relating to the Partnership Securities for any Partnership purpose at any time and from time to time to such Persons for such consideration and on such terms and conditions as shall be established by the General Partner in its sole discretion, all without the approval of any Limited Partners.

(b) Each additional Partnership Security authorized to be issued by the Partnership pursuant to Section 5.6(a) may be issued in one or more classes, or one or more series of any such classes, with such designations, preferences, rights, powers and duties (which may be senior to existing classes and series of Partnership Securities), as shall be fixed by the General Partner in the exercise of its sole discretion, including (i) the right to share Partnership profits and losses or items thereof; (ii) the right to share in Partnership distributions; (iii) the rights upon dissolution and liquidation of the Partnership; (iv) whether, and the terms and conditions upon which, the Partnership may redeem the Partnership Security; (v) whether such Partnership Security is issued with the privilege of conversion or exchange and, if so, the terms and conditions of such conversion or exchange; (vi) the terms and conditions upon which each Partnership Security will be issued, evidenced by certificates and assigned or transferred; and (vii) the right, if any, of each such Partnership Security to vote on Partnership matters, including matters relating to the relative rights, preferences and privileges of such Partnership Security.

(c) The General Partner is hereby authorized and directed to take all actions that it deems necessary or appropriate in connection with (i) each issuance of Partnership Securities and options, rights, warrants and appreciation rights relating to Partnership Securities pursuant to this Section 5.6, (ii) the conversion of the General Partner Interest or any Incentive Distribution Rights into Units pursuant to the terms of this Agreement, (iii) the admission of Additional Limited Partners and (iv) all additional issuances of Partnership Securities. The General Partner is further authorized and directed to specify the relative rights, powers and duties of the holders of the Units or other Partnership Securities being so issued. The General Partner shall do all things necessary to comply with the Delaware Act and is authorized and directed to do all things it deems to be necessary or advisable in connection with any future issuance of Partnership Securities or in connection with the conversion of the General Partner Interest or any Incentive Distribution Rights into Units pursuant to the terms of this Agreement, including compliance with any statute, rule, regulation or guideline of any federal, state or other governmental agency or any National Securities Exchange on which the Units or other Partnership Securities are listed for trading.

Section 5.7 Limitations on Issuance of Additional Partnership Securities.

The issuance of Partnership Securities pursuant to Section 5.6 shall be subject to the following restrictions and limitations:

(a) During the Subordination Period, the Partnership shall not issue (and shall not issue any options, rights, warrants or appreciation rights relating to) an aggregate of more than 1,050,000 (plus an amount, if any, equal to one half of the number of Units issued pursuant to the Over-Allotment Option, if and to the extent exercised) additional Parity Units without the prior approval of the holders of a Unit Majority. In applying this limitation, there shall be excluded Common Units and other Parity Units issued (A) in connection with the exercise of the Over-Allotment Option, (B) in accordance with Sections 5.7(b), 5.7(c) and 5.7(d), (C) upon conversion of Subordinated Units pursuant to Section 5.8, (D) upon conversion of the General Partner Interest or any Incentive Distribution Rights pursuant to Section 11.3(b), (D) pursuant to the employee benefit plans of the General Partner, the Partnership or any other Group Member, (E) upon a conversion or exchange of Parity Units issued after the date hereof into Common Units or other Parity Units; provided that the total amount of Available Cash required to pay the aggregate Minimum Quarterly Distribution on all Common Units and all Parity Units does not increase as a result of this conversion or exchange and (F) in the event of a combination or subdivision of Common Units.

(b) The Partnership may also issue an unlimited number of Parity Units, prior to the end of the Subordination Period and without the prior approval of the Unitholders, if such issuance occurs (i) in connection with an Acquisition or a Capital Improvement or (ii) within 365 days of, and the net proceeds from such issuance are used to repay debt incurred in connection with, an Acquisition or a Capital Improvement, in each case where such Acquisition or Capital Improvement involves assets that, if acquired by the Partnership as of the date that is one year prior to the first day of the Quarter in which such Acquisition is to be consummated or such

Capital Improvement is to be completed, would have resulted, on a pro forma basis, in an increase in:

(A) the amount of Adjusted Operating Surplus generated by the Partnership on a per-Unit basis (for all Outstanding Units) with respect to each of the four most recently completed Quarters (on a pro forma basis as described below) as compared to

(B) the actual amount of Adjusted Operating Surplus generated by the Partnership on a per-Unit basis (for all Outstanding Units) (excluding Adjusted Operating Surplus attributable to the Acquisition or Capital Improvement) with respect to each of such four most recently completed Quarters.

The General Partner’s good faith determination that such an increase would have resulted shall be conclusive. If the issuance of Parity Units with respect to an Acquisition or Capital Improvement occurs within the first four full Quarters after the Closing Date, then Adjusted Operating Surplus as used in clauses (A) (subject to the succeeding sentence) and (B) above shall be calculated (i) for each Quarter, if any, that commenced after the Closing Date for which actual results of operations are available, based on the actual Adjusted Operating Surplus of the Partnership generated with respect to such Quarter, and (ii) for each other Quarter, on a pro forma basis consistent with the procedures, as applicable, set forth in Appendix D to the Registration Statement. Furthermore, the amount in clause (A) shall be determined on a pro forma basis assuming that (1) all of the Parity Units to be issued in connection with or within 365 days of such Acquisition or Capital Improvement had been issued and outstanding, (2) all indebtedness for borrowed money to be incurred or assumed in connection with such Acquisition or Capital Improvement (other than any such indebtedness that is to be repaid with the proceeds of such issuance of Parity Units) had been incurred or assumed, in each case as of the commencement of such four-Quarter period, (3) the personnel expenses that would have been incurred by the Partnership in the operation of the acquired assets are the personnel expenses for employees to be retained by the Partnership in the operation of the acquired assets, and (4) the non-personnel costs and expenses are computed on the same basis as those incurred by the Partnership in the operation of the Partnership’s business at similarly situated Partnership facilities. For the purposes of this Section 5.7(b), the term “debt” shall be deemed to include indebtedness used to extend, refinance, renew, replace or defease debt originally incurred in connection with an Acquisition or Capital Improvement; provided, that, the amount of such extended, refinanced, renewed, replaced or defeased indebtedness does not exceed the principal sum of, plus accrued interest on, the indebtedness so extended, replaced renewed, replaced or defeased.

(c) The Partnership may also issue an unlimited number of Parity Units, prior to the end of the Subordination Period and without the approval of the Unitholders, if the proceeds from such issuance are used exclusively to repay indebtedness of a Group Member where the aggregate amount of distributions that would have been paid with respect to such newly issued Units, plus the related distributions on the General Partner Interest in the Partnership in respect of the four-Quarter period ending prior to the first day of the Quarter in which the issuance is to

be consummated (assuming such additional Units had been Outstanding throughout such period and that distributions equal to the distributions that were actually paid on the Outstanding Units during the period were paid on such additional Units) would not have exceeded the interest costs actually incurred during such period on the indebtedness that is to be repaid (or, if such indebtedness was not outstanding throughout the entire period, would have been incurred had such indebtedness been outstanding for the entire period). In the event that the Partnership is required to pay a prepayment penalty in connection with the repayment of such indebtedness, for purposes of the foregoing test the number of Parity Units issued to repay such indebtedness shall be deemed increased by the number of Parity Units that would need to be issued to pay such penalty.

(d) During the Subordination Period, without the prior approval of the holders of a Unit Majority, the Partnership shall not issue any additional Partnership Securities (or options, rights, warrants or appreciation rights related thereto) (i) that are entitled in any Quarter to receive in respect of the Subordination Period any distribution of Available Cash from Operating Surplus before the Common Units and any Parity Units have received (or amounts have been set aside for payment of) the Minimum Quarterly Distribution and any Cumulative Common Unit Arrearage for such Quarter or (ii) that are entitled to allocations in respect of the Subordination Period of Net Termination Gain before the Common Units and any Parity Units have been allocated Net Termination Gain pursuant to Section 6.1(c)(i)(B).

(e) During the Subordination Period, without the prior approval of the holders of a Unit Majority, the Partnership may issue additional Partnership Securities (or options, rights, warrants or appreciation rights related thereto) (i) that are not entitled in any Quarter during the Subordination Period to receive any distributions of Available Cash from Operating Surplus until after the Common Units and any Parity Units have received (or amounts have been set aside for payment of) the Minimum Quarterly Distribution and any Cumulative Common Unit Arrearage for such Quarter and (ii) that are not entitled to allocations in respect of the Subordination Period of Net Termination Gain before the Common Units and Parity Units have been allocated Net Termination Gain pursuant to Section 6.1(c)(i)(B), even if (A) the amount of Available Cash from Operating Surplus to which each such Partnership Security is entitled to receive after the Minimum Quarterly Distribution and any Cumulative Common Unit Arrearage have been paid or set aside for payment on the Common Units exceeds the Minimum Quarterly Distribution, (B) the amount of Net Termination Gain to be allocated to such Partnership Security after Net Termination Gain has been allocated to any Common Units and Parity Units pursuant to Section 6.1(c)(i)(B) exceeds the amount of such Net Termination Gain to be allocated to each Common Unit or Parity Unit or (C) the holders of such additional Partnership Securities have the right to require the Partnership or its Affiliates to repurchase such Partnership Securities at a discount, par or a premium.

(f) No fractional Units shall be issued by the Partnership.

Section 5.8 Conversion of Subordinated Units.

(a) A total of 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2005, in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest in the Partnership, during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero.

(b) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2006, in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a

Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

provided, however, that the conversion of Subordinated Units pursuant to this Section 5.8(b) may not occur until at least one year following the conversion of Subordinated Units pursuant to Section 5.8(a).

(c) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2007, in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

provided, however, that the conversion of Subordinated Units pursuant to this Section 5.8(c) may not occur until at least one year following the conversion of Subordinated Units pursuant to Section 5.8(b).

(d) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2008, in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in

right of distribution to the Subordinated Units with respect to each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the three consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Minimum Quarterly Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

provided, however, that the conversion of Subordinated Units pursuant to this Section 5.8(d) may not occur until at least one year following the conversion of Subordinated Units pursuant to Section 5.8(c).

(e) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2005, in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the two consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Second Target Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the two consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Second Target Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

(f) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2005 in respect of which:

(i) distributions under Section 6.4 in respect of all Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units with respect to each of the two consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Third Target Distribution on all of the Outstanding Common Units and Subordinated Units and any other Outstanding Units that are senior or equal in right of distribution to the Subordinated Units during such periods;

(ii) the Adjusted Operating Surplus generated during each of the two consecutive, non-overlapping four-Quarter periods immediately preceding such date equaled or exceeded the sum of the Third Target Distribution on all of the Common Units, Subordinated Units and any other Units that are senior or equal in right of distribution to the Subordinated Units that were Outstanding during such periods on a Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

(g) In the event that less than all of the Outstanding Subordinated Units shall convert into Common Units pursuant to Sections 5.8(a)-(f) at a time when there shall be more than one holder of Subordinated Units, then, unless all of the holders of Subordinated Units shall agree to a different allocation, the Subordinated Units that are to be converted into Common Units shall be allocated among the holders of Subordinated Units pro rata based on the number of Subordinated Units held by each such holder.

(h) Any Subordinated Units that are not converted into Common Units pursuant to Section 5.8(a)-(f) shall convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of the final Quarter of the Subordination Period.

(i) Notwithstanding any other provision of this Agreement, all the then Outstanding Subordinated Units will automatically convert into Common Units on a one-for-one basis as set forth in, and pursuant to the terms of, Section 11.4.

(j) A Subordinated Unit that has converted into a Common Unit shall be subject to the provisions of Section 6.7(b).

Section 5.9 Limited Preemptive Right.

Except as provided in this Section 5.9 and in Section 5.2, no Person shall have any preemptive, preferential or other similar right with respect to the issuance of any Partnership Security, whether unissued, held in the treasury or hereafter created. The General Partner shall have the right, which it may from time to time assign in whole or in part to any of its Affiliates, to purchase Partnership Securities from the Partnership whenever, and on the same terms that, the Partnership issues Partnership Securities to Persons other than the General Partner and its Affiliates, to the extent necessary to maintain the Percentage Interests of the General Partner and its Affiliates equal to that which existed immediately prior to the issuance of such Partnership Securities.

Section 5.10 Splits and Combinations.

(a) Subject to Sections 5.10(d), 6.6 and 6.9 (dealing with adjustments of distribution levels), the Partnership may make a Pro Rata distribution of Partnership Securities to all Record Holders or may effect a subdivision or combination of Partnership Securities so long as, after any such event, each Partner shall have the same Percentage Interest in the Partnership as before such event, and any amounts calculated on a per Unit basis (including any Common Unit Arrearage or Cumulative Common Unit Arrearage) or stated as a number of Units (including the number of Subordinated Units that may convert prior to the end of the Subordination Period and the number of additional Parity Units that may be issued pursuant to Section 5.7 without a Unitholder vote) are proportionately adjusted retroactive to the beginning of the Partnership.

(b) Whenever such a distribution, subdivision or combination of Partnership Securities is declared, the General Partner shall select a Record Date as of which the distribution, subdivision or combination shall be effective and shall send notice thereof at least 20 days prior to such Record Date to each Record Holder as of a date not less than 10 days prior to the date of such notice. The General Partner also may cause a firm of independent public accountants selected by it to calculate the number of Partnership Securities to be held by each Record Holder after giving effect to such distribution, subdivision or combination. The General Partner shall be entitled to rely on any certificate provided by such firm as conclusive evidence of the accuracy of such calculation.

(c) Promptly following any such distribution, subdivision or combination, the Partnership may issue Certificates to the Record Holders of Partnership Securities as of the applicable Record Date representing the new number of Partnership Securities held by such Record Holders, or the General Partner may adopt such other procedures as it may deem appropriate to reflect such changes. If any such combination results in a smaller total number of Partnership Securities Outstanding, the Partnership shall require, as a condition to the delivery to a Record Holder of such new Certificate, the surrender of any Certificate held by such Record Holder immediately prior to such Record Date.

(d) The Partnership shall not issue fractional Units upon any distribution, subdivision or combination of Units. If a distribution, subdivision or combination of Units would result in the

issuance of fractional Units but for the provisions of Section 5.7(f) and this Section 5.10(d), each fractional Unit shall be rounded to the nearest whole Unit (and a 0.5 Unit shall be rounded to the next higher Unit).

Section 5.11 Fully Paid and Non-Assessable Nature of Limited Partner Interests.

All Limited Partner Interests issued pursuant to, and in accordance with the requirements of, this Article V shall be fully paid and non-assessable Limited Partner Interests in the Partnership, except as such non-assessability may be affected by Section 17-607 of the Delaware Act.

ARTICLE VI

ALLOCATIONS AND DISTRIBUTIONS

Section 6.1 Allocations for Capital Account Purposes.

For purposes of maintaining the Capital Accounts and in determining the rights of the Partners among themselves, the Partnership’s items of income, gain, loss and deduction (computed in accordance with Section 5.5(b)) shall be allocated among the Partners in each taxable year (or portion thereof) as provided herein below.

(a) Net Income. After giving effect to the special allocations set forth in Section 6.1(d), Net Income for each taxable year and all items of income, gain, loss and deduction taken into account in computing Net Income for such taxable year shall be allocated as follows:

(i) First, 100% to the General Partner, in an amount equal to the aggregate Net Losses allocated to the General Partner pursuant to Section 6.1(b)(iii) for all previous taxable years until the aggregate Net Income allocated to the General Partner pursuant to this Section 6.1(a)(i) for the current taxable year and all previous taxable years is equal to the aggregate Net Losses allocated to the General Partner pursuant to Section 6.1(b)(iii) for all previous taxable years;

(ii) Second, 2% to the General Partner, in an amount equal to the aggregate Net Losses allocated to the General Partner pursuant to Section 6.1(b)(ii) for all previous taxable years and 98% to the Unitholders, in accordance with their respective Percentage Interests, until the aggregate Net Income allocated to such Partners pursuant to this Section 6.1(a)(ii) for the current taxable year and all previous taxable years is equal to the aggregate Net Losses allocated to such Partners pursuant to Section 6.1(b)(ii) for all previous taxable years; and

(iii) Third, 2% to the General Partner, and 98% to the Unitholders, Pro Rata.

(b) Net Losses. After giving effect to the special allocations set forth in Section 6.1(d), Net Losses for each taxable period and all items of income, gain, loss and deduction taken into account in computing Net Losses for such taxable period shall be allocated as follows:

(i) First, 2% to the General Partner, and 98% to the Unitholders, Pro Rata, until the aggregate Net Losses allocated pursuant to this Section 6.1(b)(i) for the current taxable year and all previous taxable years is equal to the aggregate Net Income allocated to such Partners pursuant to Section 6.1(a)(iii) for all previous taxable years, provided that the Net Losses shall not be allocated pursuant to this Section 6.1(b)(i) to the extent that such allocation would cause any Unitholder to have a deficit balance in its Adjusted Capital Account at the end of such taxable year (or increase any existing deficit balance in its Adjusted Capital Account);

(ii) Second, 2% to the General Partner, and 98% to the Unitholders, Pro Rata; provided, that Net Losses shall not be allocated pursuant to this Section 6.1(b)(ii) to the extent that such allocation would cause any Unitholder to have a deficit balance in its Adjusted Capital Account at the end of such taxable year (or increase any existing deficit balance in its Adjusted Capital Account);

(iii) Third, the balance, if any, 100% to the General Partner.

(c) Net Termination Gains and Losses. After giving effect to the special allocations set forth in Section 6.1(d), all items of income, gain, loss and deduction taken into account in computing Net Termination Gain or Net Termination Loss for such taxable period shall be allocated in the same manner as such Net Termination Gain or Net Termination Loss is allocated hereunder. All allocations under this Section 6.1(c) shall be made after Capital Account balances have been adjusted by all other allocations provided under this Section 6.1 and after all distributions of Available Cash provided under Sections 6.4 and 6.5 have been made; provided, however, that solely for purposes of this Section 6.1(c), Capital Accounts shall not be adjusted for distributions made pursuant to Section 12.4.

(i) If a Net Termination Gain is recognized (or deemed recognized pursuant to Section 5.5(d)), such Net Termination Gain shall be allocated among the Partners in the following manner (and the Capital Accounts of the Partners shall be increased by the amount so allocated in each of the following subclauses, in the order listed, before an allocation is made pursuant to the next succeeding subclause):

(A) First, to each Partner having a deficit balance in its Capital Account, in the proportion that such deficit balance bears to the total deficit balances in the Capital Accounts of all Partners, until each such Partner has been allocated Net Termination Gain equal to any such deficit balance in its Capital Account;

(B) Second, 98% to all Unitholders holding Common Units, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each

Common Unit then Outstanding is equal to the sum of (1) its Unrecovered Capital plus (2) the Minimum Quarterly Distribution for the Quarter during which the Liquidation Date occurs, reduced by any distribution pursuant to Section 6.4(a)(i) or (b)(i) with respect to such Common Unit for such Quarter (the amount determined pursuant to this clause (2) is hereinafter defined as the “Unpaid MQD”) plus (3) any then existing Cumulative Common Unit Arrearage;

(C) Third, if such Net Termination Gain is recognized (or is deemed to be recognized) prior to the expiration of the Subordination Period, 98% to all Unitholders holding Subordinated Units, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Subordinated Unit then Outstanding equals the sum of (1) its Unrecovered Capital, determined for the taxable year (or portion thereof) to which this allocation of gain relates, plus (2) the Minimum Quarterly Distribution for the Quarter during which the Liquidation Date occurs, reduced by any distribution pursuant to Section 6.4(a)(iii) with respect to such Subordinated Unit for such Quarter;

(D) Fourth, 98% to all Unitholders, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Common Unit then Outstanding is equal to the sum of (1) its Unrecovered Capital, plus (2) the Unpaid MQD, plus (3) any then existing Cumulative Common Unit Arrearage, plus (4) the excess of (aa) the First Target Distribution less the Minimum Quarterly Distribution for each Quarter of the Partnership’s existence over (bb) the cumulative per Unit amount of any distributions of Available Cash that is deemed to be Operating Surplus made pursuant to Sections 6.4(a)(iv) and 6.4(b)(ii) (the sum of (1) plus (2) plus (3) plus (4) is hereinafter defined as the “First Liquidation Target Amount”);

(E) Fifth, 85% to all Unitholders, Pro Rata, 13% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Common Unit then Outstanding is equal to the sum of (1) the First Liquidation Target Amount, plus (2) the excess of (aa) the Second Target Distribution less the First Target Distribution for each Quarter of the Partnership’s existence over (bb) the cumulative per Unit amount of any distributions of Available Cash that is deemed to be Operating Surplus made pursuant to Sections 6.4(a)(v) and 6.4(b)(iii) (the sum of (1) plus (2) is hereinafter defined as the “Second Liquidation Target Amount”);

(F) Sixth, 75% to all Unitholders, Pro Rata, 23% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Common Unit then Outstanding is equal to the sum of (1) the Second Liquidation Target Amount, plus (2) the excess of (aa) the Third Target Distribution less the Second Target Distribution for each Quarter of the Partnership’s existence over (bb) the cumulative per Unit amount of any distributions of Available Cash that is deemed to be Operating Surplus made

pursuant to Sections 6.4(a)(vi)and 6.4(b)(iv) (the sum of (1) plus (2) is hereinafter defined as the “Third Liquidation Target Amount”); and

(G) Finally, any remaining amount 50% to all Unitholders, Pro Rata, 48% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner.

(ii) If a Net Termination Loss is recognized (or deemed recognized pursuant to Section 5.5(d)), such Net Termination Loss shall be allocated among the Partners in the following manner:

(A) First, if such Net Termination Loss is recognized (or is deemed to be recognized) prior to the conversion of the last Outstanding Subordinated Unit, 98% to the Unitholders holding Subordinated Units, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Subordinated Unit then Outstanding has been reduced to zero;

(B) Second, 98% to all Unitholders holding Common Units, Pro Rata, and 2% to the General Partner, until the Capital Account in respect of each Common Unit then Outstanding has been reduced to zero; and

(C) Third, the balance, if any, 100% to the General Partner.

(d) Special Allocations. Notwithstanding any other provision of this Section 6.1, the following special allocations shall be made for such taxable period:

(i) Partnership Minimum Gain Chargeback. Notwithstanding any other provision of this Section 6.1, if there is a net decrease in Partnership Minimum Gain during any Partnership taxable period, each Partner shall be allocated items of Partnership income and gain for such period (and, if necessary, subsequent periods) in the manner and amounts provided in Treasury Regulation Sections 1.704-2(f)(6), 1.704-2(g)(2) and 1.704-2(j)(2)(i), or any successor provision. For purposes of this Section 6.1(d), each Partner’s Adjusted Capital Account balance shall be determined, and the allocation of income or gain required hereunder shall be effected, prior to the application of any other allocations pursuant to this Section 6.1(d) with respect to such taxable period (other than an allocation pursuant to Sections 6.1(d)(vi) and 6.1(d)(vii)). This Section 6.1(d)(i) is intended to comply with the Partnership Minimum Gain chargeback requirement in Treasury Regulation Section 1.704-2(f) and shall be interpreted consistently therewith.

(ii) Chargeback of Partner Nonrecourse Debt Minimum Gain. Notwithstanding the other provisions of this Section 6.1 (other than Section 6.1(d)(i)), except as provided in Treasury Regulation Section 1.704-2(i)(4), if there is a net decrease in Partner Nonrecourse Debt Minimum Gain during any Partnership taxable period, any Partner with a share of Partner Nonrecourse Debt Minimum Gain at the beginning of

such taxable period shall be allocated items of Partnership income and gain for such period (and, if necessary, subsequent periods) in the manner and amounts provided in Treasury Regulation Sections 1.704-2(i)(4) and 1.704-2(j)(2)(ii), or any successor provisions. For purposes of this Section 6.1(d), each Partner’s Adjusted Capital Account balance shall be determined, and the allocation of income or gain required hereunder shall be effected, prior to the application of any other allocations pursuant to this Section 6.1(d), other than Section 6.1(d)(i) and other than an allocation pursuant to Sections 6.1(d)(vi) and 6.1(d)(vii), with respect to such taxable period. This Section 6.1(d)(ii) is intended to comply with the chargeback of items of income and gain requirement in Treasury Regulation Section 1.704-2(i)(4) and shall be interpreted consistently therewith.

(iii) Priority Allocations.

(A) If the amount of cash or the Net Agreed Value of any property distributed (except cash or property distributed pursuant to Section 12.4) to any Unitholder with respect to its Units for a taxable year is greater (on a per Unit basis) than the amount of cash or the Net Agreed Value of property distributed to the other Unitholders with respect to their Units (on a per Unit basis), then (1) each Unitholder receiving such greater cash or property distribution shall be allocated gross income in an amount equal to the product of (aa) the amount by which the distribution (on a per Unit basis) to such Unitholder exceeds the distribution (on a per Unit basis) to the Unitholders receiving the smallest distribution and (bb) the number of Units owned by the Unitholder receiving the greater distribution; and (2) the General Partner shall be allocated gross income in an aggregate amount equal to 1/98th of the sum of the amounts allocated in clause (1) above.

(B) After the application of Section 6.1(d)(iii)(A), all or any portion of the remaining items of Partnership gross income or gain for the taxable period, if any, shall be allocated 100% to the holders of Incentive Distribution Rights, Pro Rata, until the aggregate amount of such items allocated to the holders of Incentive Distribution Rights pursuant to this paragraph 6.1(d)(iii)(B) for the current taxable year and all previous taxable years is equal to the cumulative amount of all Incentive Distributions made to the holders of Incentive Distribution Rights from the Closing Date to a date 45 days after the end of the current taxable year.

(iv) Qualified Income Offset. In the event any Partner unexpectedly receives any adjustments, allocations or distributions described in Treasury Regulation Sections 1.704-1(b)(2)(ii)(d)(4), 1.704-1(b)(2)(ii)(d)(5), or 1.704-1(b)(2)(ii)(d)(6), items of Partnership income and gain shall be specially allocated to such Partner in an amount and manner sufficient to eliminate, to the extent required by the Treasury Regulations promulgated under Section 704(b) of the Code, the deficit balance, if any, in its Adjusted Capital Account created by such adjustments, allocations or distributions as quickly as

possible unless such deficit balance is otherwise eliminated pursuant to Section 6.1(d)(i) or (ii).

(v) Gross Income Allocations. In the event any Partner has a deficit balance in its Capital Account at the end of any Partnership taxable period in excess of the sum of (A) the amount such Partner is required to restore pursuant to the provisions of this Agreement and (B) the amount such Partner is deemed obligated to restore pursuant to Treasury Regulation Sections 1.704-2(g) and 1.704-2(i)(5), such Partner shall be specially allocated items of Partnership gross income and gain in the amount of such excess as quickly as possible; provided, that an allocation pursuant to this Section 6.1(d)(v) shall be made only if and to the extent that such Partner would have a deficit balance in its Capital Account as adjusted after all other allocations provided for in this Section 6.1 have been tentatively made as if this Section 6.1(d)(v) were not in this Agreement.

(vi) Nonrecourse Deductions. Nonrecourse Deductions for any taxable period shall be allocated to the Partners in accordance with their respective Percentage Interests. If the General Partner determines in its good faith discretion that the Partnership’s Nonrecourse Deductions must be allocated in a different ratio to satisfy the safe harbor requirements of the Treasury Regulations promulgated under Section 704(b) of the Code, the General Partner is authorized, upon notice to the other Partners, to revise the prescribed ratio to the numerically closest ratio that does satisfy such requirements.

(vii) Partner Nonrecourse Deductions. Partner Nonrecourse Deductions for any taxable period shall be allocated 100% to the Partner that bears the Economic Risk of Loss with respect to the Partner Nonrecourse Debt to which such Partner Nonrecourse Deductions are attributable in accordance with Treasury Regulation Section 1.704-2(i). If more than one Partner bears the Economic Risk of Loss with respect to a Partner Nonrecourse Debt, such Partner Nonrecourse Deductions attributable thereto shall be allocated between or among such Partners in accordance with the ratios in which they share such Economic Risk of Loss.

(viii) Nonrecourse Liabilities. For purposes of Treasury Regulation Section 1.752-3(a)(3), the Partners agree that Nonrecourse Liabilities of the Partnership in excess of the sum of (A) the amount of Partnership Minimum Gain and (B) the total amount of Nonrecourse Built-in Gain shall be allocated among the Partners in accordance with their respective Percentage Interests.

(ix) Code Section 754 Adjustments. To the extent an adjustment to the adjusted tax basis of any Partnership asset pursuant to Section 734(b) or 743(c) of the Code is required, pursuant to Treasury Regulation Section 1.704-1(b)(2)(iv)(m), to be taken into account in determining Capital Accounts, the amount of such adjustment to the Capital Accounts shall be treated as an item of gain (if the adjustment increases the basis of the asset) or loss (if the adjustment decreases such basis), and such item of gain or loss shall be specially allocated to the Partners in a manner consistent with the manner in which

their Capital Accounts are required to be adjusted pursuant to such Section of the Treasury Regulations.

(x) Economic Uniformity. At the election of the General Partner with respect to any taxable period ending upon, or after, the termination of the Subordination Period, all or a portion of the remaining items of Partnership gross income or gain for such taxable period, after taking into account allocations pursuant to Section 6.1(d)(iii), shall be allocated 100% to each Partner holding Subordinated Units that are Outstanding as of the termination of the Subordination Period (“Final Subordinated Units”) in the proportion of the number of Final Subordinated Units held by such Partner to the total number of Final Subordinated Units then Outstanding, until each such Partner has been allocated an amount of gross income or gain which increases the Capital Account maintained with respect to such Final Subordinated Units to an amount equal to the product of (A) the number of Final Subordinated Units held by such Partner and (B) the Per Unit Capital Amount for a Common Unit. The purpose of this allocation is to establish uniformity between the Capital Accounts underlying Final Subordinated Units and the Capital Accounts underlying Common Units held by Persons other than the General Partner and its Affiliates immediately prior to the conversion of such Final Subordinated Units into Common Units. This allocation method for establishing such economic uniformity will only be available to the General Partner if the method for allocating the Capital Account maintained with respect to the Subordinated Units between the transferred and retained Subordinated Units pursuant to Section 5.5(c)(ii) does not otherwise provide such economic uniformity to the Final Subordinated Units.

(xi) Curative Allocation.

(A) Notwithstanding any other provision of this Section 6.1, other than the Required Allocations, the Required Allocations shall be taken into account in making the Agreed Allocations so that, to the extent possible, the net amount of items of income, gain, loss and deduction allocated to each Partner pursuant to the Required Allocations and the Agreed Allocations, together, shall be equal to the net amount of such items that would have been allocated to each such Partner under the Agreed Allocations had the Required Allocations and the related Curative Allocation not otherwise been provided in this Section 6.1. Notwithstanding the preceding sentence, Required Allocations relating to (1) Nonrecourse Deductions shall not be taken into account except to the extent that there has been a decrease in Partnership Minimum Gain and (2) Partner Nonrecourse Deductions shall not be taken into account except to the extent that there has been a decrease in Partner Nonrecourse Debt Minimum Gain. Allocations pursuant to this Section 6.1(d)(xi)(A) shall only be made with respect to Required Allocations to the extent the General Partner reasonably determines that such allocations will otherwise be inconsistent with the economic agreement among the Partners. Further, allocations pursuant to this Section 6.1(d)(xi)(A) shall be deferred with respect to allocations pursuant to clauses (1) and (2) hereof

to the extent the General Partner reasonably determines that such allocations are likely to be offset by subsequent Required Allocations.

(B) The General Partner shall have reasonable discretion, with respect to each taxable period, to (1) apply the provisions of Section 6.1(d)(xi)(A) in whatever order is most likely to minimize the economic distortions that might otherwise result from the Required Allocations, and (2) divide all allocations pursuant to Section 6.1(d)(xi)(A) among the Partners in a manner that is likely to minimize such economic distortions.

(xii) Corrective Allocations. In the event of any allocation of Additional Book Basis Derivative Items or any Book-Down Event or any recognition of a Net Termination Loss, the following rules shall apply:

(A) In the case of any allocation of Additional Book Basis Derivative Items (other than an allocation of Unrealized Gain or Unrealized Loss under Section 5.5(d) hereof), the General Partner shall allocate additional items of gross income and gain away from the holders of Incentive Distribution Rights to the Unitholders and the General Partner, or additional items of deduction and loss away from the Unitholders and the General Partner to the holders of Incentive Distribution Rights, to the extent that the Additional Book Basis Derivative Items allocated to the Unitholders or the General Partner exceed their Share of Additional Book Basis Derivative Items. For this purpose, the Unitholders and the General Partner shall be treated as being allocated Additional Book Basis Derivative Items to the extent that such Additional Book Basis Derivative Items have reduced the amount of income that would otherwise have been allocated to the Unitholders or the General Partner under the Partnership Agreement (e.g., Additional Book Basis Derivative Items taken into account in computing cost of goods sold would reduce the amount of book income otherwise available for allocation among the Partners). Any allocation made pursuant to this Section 6.1(d)(xii)(A) shall be made after all of the other Agreed Allocations have been made as if this Section 6.1(d)(xii) were not in this Agreement and, to the extent necessary, shall require the reallocation of items that have been allocated pursuant to such other Agreed Allocations.

(B) In the case of any negative adjustments to the Capital Accounts of the Partners resulting from a Book-Down Event or from the recognition of a Net Termination Loss, such negative adjustment (1) shall first be allocated, to the extent of the Aggregate Remaining Net Positive Adjustments, in such a manner, as reasonably determined by the General Partner, that to the extent possible the aggregate Capital Accounts of the Partners will equal the amount which would have been the Capital Account balance of the Partners if no prior Book-Up Events had occurred, and (2) any negative adjustment in excess of the Aggregate Remaining Net Positive Adjustments shall be allocated pursuant to Section 6.1(c) hereof.

(C) In making the allocations required under this Section 6.1(d)(xii), the General Partner, in its sole discretion, may apply whatever conventions or other methodology it deems reasonable to satisfy the purpose of this Section 6.1(d)(xii).

(xiii) The first $1,660,000 of depreciation or other amortization deductions attributable to the New ▇▇▇▇ Plant and any other deductions funded by the General Partner’s ▇▇▇▇ Contribution shall be allocated 100% to the General Partner.

(xiv) Any compensation expense attributable to deemed contributions by the General Partner resulting from the application of APB 25 and/or FAS 123R to the transfer of ownership interests in the General Partner and subordinated units of the Partnership to certain directors and officers of the General Partner and of the Company, shall be allocated 100% to the General Partner.

Section 6.2 Allocations for Tax Purposes.

(a) Except as otherwise provided herein, for federal income tax purposes, each item of income, gain, loss and deduction shall be allocated among the Partners in the same manner as its correlative item of “book” income, gain, loss or deduction is allocated pursuant to Section 6.1.

(b) In an attempt to eliminate Book-Tax Disparities attributable to a Contributed Property or Adjusted Property, items of income, gain, loss, depreciation, amortization and cost recovery deductions shall be allocated for federal income tax purposes among the Partners as follows:

(i) (A) In the case of a Contributed Property, such items attributable thereto shall be allocated among the Partners in the manner provided under Section 704(c) of the Code that takes into account the variation between the Agreed Value of such property and its adjusted basis at the time of contribution; and (B) any item of Residual Gain or Residual Loss attributable to a Contributed Property shall be allocated among the Partners in the same manner as its correlative item of “book” gain or loss is allocated pursuant to Section 6.1.

(ii) (A) In the case of an Adjusted Property, such items shall (1) first, be allocated among the Partners in a manner consistent with the principles of Section 704(c) of the Code to take into account the Unrealized Gain or Unrealized Loss attributable to such property and the allocations thereof pursuant to Section 5.5(d)(i) or 5.5(d)(ii), and (2) second, in the event such property was originally a Contributed Property, be allocated among the Partners in a manner consistent with Section 6.2(b)(i)(A); and (B) any item of Residual Gain or Residual Loss attributable to an Adjusted Property shall be allocated among the Partners in the same manner as its correlative item of “book” gain or loss is allocated pursuant to Section 6.1.

(iii) The General Partner shall apply the principles of Treasury Regulation Section 1.704-3(d) to eliminate Book-Tax Disparities.

(c) For the proper administration of the Partnership and for the preservation of uniformity of the Limited Partner Interests (or any class or classes thereof), the General Partner shall have sole discretion to (i) adopt such conventions as it deems appropriate in determining the amount of depreciation, amortization and cost recovery deductions; (ii) make special allocations for federal income tax purposes of income (including, without limitation, gross income) or deductions; and (iii) amend the provisions of this Agreement as appropriate (x) to reflect the proposal or promulgation of Treasury Regulations under Section 704(b) or Section 704(c) of the Code or (y) otherwise to preserve or achieve uniformity of the Limited Partner Interests (or any class or classes thereof). The General Partner may adopt such conventions, make such allocations and make such amendments to this Agreement as provided in this Section 6.2(c) only if such conventions, allocations or amendments would not have a material adverse effect on the Partners, the holders of any class or classes of Limited Partner Interests issued and Outstanding or the Partnership, and if such allocations are consistent with the principles of Section 704 of the Code.

(d) The General Partner in its discretion may determine to depreciate or amortize the portion of an adjustment under Section 743(b) of the Code attributable to unrealized appreciation in any Adjusted Property (to the extent of the unamortized Book-Tax Disparity) using a predetermined rate derived from the depreciation or amortization method and useful life applied to the Partnership’s common basis of such property, despite any inconsistency of such approach with Treasury Regulation Section 1.167(c)-l(a)(6) or any successor regulations thereto. If the General Partner determines that such reporting position cannot reasonably be taken, the General Partner may adopt depreciation and amortization conventions under which all purchasers acquiring Limited Partner Interests in the same month would receive depreciation and amortization deductions, based upon the same applicable rate as if they had purchased a direct interest in the Partnership’s property. If the General Partner chooses not to utilize such aggregate method, the General Partner may use any other reasonable depreciation and amortization conventions to preserve the uniformity of the intrinsic tax characteristics of any Limited Partner Interests that would not have a material adverse effect on the Limited Partners or the Record Holders of any class or classes of Limited Partner Interests.

(e) Any gain allocated to the Partners upon the sale or other taxable disposition of any Partnership asset shall, to the extent possible, after taking into account other required allocations of gain pursuant to this Section 6.2, be characterized as Recapture Income in the same proportions and to the same extent as such Partners (or their predecessors in interest) have been allocated any deductions directly or indirectly giving rise to the treatment of such gains as Recapture Income.

(f) All items of income, gain, loss, deduction and credit recognized by the Partnership for federal income tax purposes and allocated to the Partners in accordance with the provisions hereof shall be determined without regard to any election under Section 754 of the Code which may be made by the Partnership; provided, however, that such allocations, once

made, shall be adjusted as necessary or appropriate to take into account those adjustments permitted or required by Sections 734 and 743 of the Code.

(g) Each item of Partnership income, gain, loss and deduction shall for federal income tax purposes, be determined on an annual basis and prorated on a monthly basis and shall be allocated to the Partners as of the opening of the New York Stock Exchange on the first Business Day of each month; provided, however, that (i) such items for the period beginning on the Closing Date and ending on the last day of the month in which the Option Closing Date or the expiration of the Over-allotment Option occurs shall be allocated to the Partners as of the opening of the New York Stock Exchange on the first Business Day of the next succeeding month; and provided, further, that gain or loss on a sale or other disposition of any assets of the Partnership or any other extraordinary item of income or loss realized and recognized other than in the ordinary course of business, as determined by the General Partner in its sole discretion, shall be allocated to the Partners as of the opening of the New York Stock Exchange on the first Business Day of the month in which such gain or loss is recognized for federal income tax purposes. The General Partner may revise, alter or otherwise modify such methods of allocation as it determines necessary or appropriate in its sole discretion, to the extent permitted or required by Section 706 of the Code and the regulations or rulings promulgated thereunder.

(h) Allocations that would otherwise be made to a Limited Partner under the provisions of this Article VI shall instead be made to the beneficial owner of Limited Partner Interests held by a nominee in any case in which the nominee has furnished the identity of such owner to the Partnership in accordance with Section 6031(c) of the Code or any other method acceptable to the General Partner in its sole discretion.

Section 6.3 Requirement and Characterization of Distributions; Distributions to Record Holders.

(a) Within 45 days following the end of each Quarter commencing with the Quarter ending on June 30, 2002, an amount equal to 100% of Available Cash with respect to such Quarter shall, subject to Section 17-607 of the Delaware Act, be distributed in accordance with this Article VI by the Partnership to the Partners as of the Record Date selected by the General Partner in its reasonable discretion. All amounts of Available Cash distributed by the Partnership on any date from any source shall be deemed to be Operating Surplus until the sum of all amounts of Available Cash theretofore distributed by the Partnership to the Partners pursuant to Section 6.4 equals the Operating Surplus from the Closing Date through the close of the immediately preceding Quarter. Any remaining amounts of Available Cash distributed by the Partnership on such date shall, except as otherwise provided in Section 6.5, be deemed to be “Capital Surplus.” All distributions required to be made under this Agreement shall be made subject to Section 17-607 of the Delaware Act.

(b) Notwithstanding Section 6.3(a), in the event of the dissolution and liquidation of the Partnership, all receipts received during or after the Quarter in which the Liquidation Date occurs, other than from borrowings described in (a)(ii) of the definition of Available Cash, shall

be applied and distributed solely in accordance with, and subject to the terms and conditions of, Section 12.4.

(c) The General Partner shall have the discretion to treat taxes paid by the Partnership on behalf of, or amounts withheld with respect to, all or less than all of the Partners, as a distribution of Available Cash to such Partners.

(d) Each distribution in respect of a Partnership Interest shall be paid by the Partnership, directly or through the Transfer Agent or through any other Person or agent, only to the Record Holder of such Partnership Interest as of the Record Date set for such distribution. Such payment shall constitute full payment and satisfaction of the Partnership’s liability in respect of such payment, regardless of any claim of any Person who may have an interest in such payment by reason of an assignment or otherwise.

Section 6.4 Distributions of Available Cash from Operating Surplus.

(a) During Subordination Period. Available Cash with respect to any Quarter within the Subordination Period that is deemed to be Operating Surplus pursuant to the provisions of Section 6.3 or 6.5 shall, subject to Section 17-607 of the Delaware Act, be distributed as follows, except as otherwise required by Section 5.6(b) in respect of additional Partnership Securities issued pursuant thereto:

(i) First, 98% to the Unitholders holding Common Units, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the Minimum Quarterly Distribution for such Quarter;

(ii) Second, 98% to the Unitholders holding Common Units, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the Cumulative Common Unit Arrearage existing with respect to such Quarter;

(iii) Third, 98% to the Unitholders holding Subordinated Units, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Subordinated Unit then Outstanding an amount equal to the Minimum Quarterly Distribution for such Quarter;

(iv) Fourth, 98% to all Unitholders, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the First Target Distribution over the Minimum Quarterly Distribution for such Quarter;

(v) Fifth, 85% to all Unitholders, Pro Rata, 13% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the Second Target Distribution over the First Target Distribution for such Quarter;

(vi) Sixth, 75% to all Unitholders, Pro Rata, 23% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the Third Target Distribution over the Second Target Distribution for such Quarter; and

(vii) Thereafter, 50% to all Unitholders, Pro Rata, 48% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner;

provided, however, if the Minimum Quarterly Distribution, the First Target Distribution, the Second Target Distribution and the Third Target Distribution have been reduced to zero pursuant to the second sentence of Section 6.6(a), the distribution of Available Cash that is deemed to be Operating Surplus with respect to any Quarter will be made solely in accordance with Section 6.4(a)(vii).

(b) After Subordination Period. Available Cash with respect to any Quarter after the Subordination Period that is deemed to be Operating Surplus pursuant to the provisions of Section 6.3 or 6.5, subject to Section 17-607 of the Delaware Act, shall be distributed as follows, except as otherwise required by Section 5.6(b) in respect of additional Partnership Securities issued pursuant thereto:

(i) First, 98% to all Unitholders, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the Minimum Quarterly Distribution for such Quarter;

(ii) Second, 98% to all Unitholders, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the First Target Distribution over the Minimum Quarterly Distribution for such Quarter;

(iii) Third, 85% to all Unitholders, Pro Rata, 13% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the Second Target Distribution over the First Target Distribution for such Quarter;

(iv) Fourth, 75% to all Unitholders, Pro Rata, 23% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Unit then Outstanding an amount equal to the excess of the Third Target Distribution over the Second Target Distribution for such Quarter; and

(v) Thereafter, 50% to all Unitholders, Pro Rata, 48% to the holders of the Incentive Distribution Rights, Pro Rata, and 2% to the General Partner;

Section 6.5 Distributions of Available Cash from Capital Surplus.

Available Cash that is deemed to be Capital Surplus pursuant to the provisions of Section 6.3(a) shall, subject to Section 17-607 of the Delaware Act, be distributed, unless the provisions of Section 6.3 require otherwise, 98% to all Unitholders, Pro Rata, and 2% to the General Partner, until a hypothetical holder of a Common Unit acquired on the Closing Date has received with respect to such Common Unit, during the period since the Closing Date through such date, distributions of Available Cash that are deemed to be Capital Surplus in an aggregate amount equal to the Initial Unit Price. Available Cash that is deemed to be Capital Surplus shall then be distributed 98% to all Unitholders holding Common Units, Pro Rata, and 2% to the General Partner, until there has been distributed in respect of each Common Unit then Outstanding an amount equal to the Cumulative Common Unit Arrearage. Thereafter, all Available Cash shall be distributed as if it were Operating Surplus and shall be distributed in accordance with Section 6.4.

Section 6.6 Adjustment of Minimum Quarterly Distribution and Target Distribution Levels.

(a) The Minimum Quarterly Distribution, First Target Distribution, Second Target Distribution, Third Target Distribution, Common Unit Arrearages and Cumulative Common Unit Arrearages shall be proportionately adjusted in the event of any distribution, combination or subdivision (whether effected by a distribution payable in Units or otherwise) of Units or other Partnership Securities in accordance with Section 5.10. In the event of a distribution of Available Cash that is deemed to be from Capital Surplus, the then applicable Minimum Quarterly Distribution, First Target Distribution, Second Target Distribution and Third Target Distribution, shall be adjusted proportionately downward to equal the product obtained by multiplying the otherwise applicable Minimum Quarterly Distribution, First Target Distribution, Second Target Distribution and Third Target Distribution, as the case may be, by a fraction of which the numerator is the Unrecovered Capital of the Common Units immediately after giving effect to such distribution and of which the denominator is the Unrecovered Capital of the Common Units immediately prior to giving effect to such distribution.

(b) The Minimum Quarterly Distribution, First Target Distribution, Second Target Distribution and Third Target Distribution, shall also be subject to adjustment pursuant to Section 6.9.

Section 6.7 Special Provisions Relating to the Holders of Subordinated Units.

(a) Except with respect to the right to vote on or approve matters requiring the vote or approval of a percentage of the holders of Outstanding Common Units and the right to participate in allocations of income, gain, loss and deduction and distributions made with respect to Common Units, the holder of a Subordinated Unit shall have all of the rights and obligations of a Unitholder holding Common Units hereunder; provided, however, that immediately upon the conversion of Subordinated Units into Common Units pursuant to Section 5.8, the Unitholder holding a Subordinated Unit shall possess all of the rights and obligations of a Unitholder holding Common Units hereunder, including the right to vote as a Common Unitholder and the right to participate in allocations of income, gain, loss and deduction and distributions made with respect to Common Units; provided, however, that such converted Subordinated Units shall remain subject to the provisions of Sections 5.5(c)(ii), 6.1(d)(x) and 6.7(b).

(b) The Unitholder holding a Subordinated Unit which has converted into a Common Unit pursuant to Section 5.8 shall not be issued a Common Unit Certificate pursuant to Section 4.1, and shall not be permitted to transfer its converted Subordinated Units to a Person which is not an Affiliate of the holder until such time as the General Partner determines, based on advice of counsel, that a converted Subordinated Unit should have, as a substantive matter, like intrinsic economic and federal income tax characteristics, in all material respects, to the intrinsic economic and federal income tax characteristics of an Initial Common Unit. In connection with the condition imposed by this Section 6.7(b), the General Partner may take whatever reasonable steps are required to provide economic uniformity to the converted Subordinated Units in preparation for a transfer of such converted Subordinated Units, including the application of Sections 5.5(c)(ii) and 6.1(d)(x); provided, however, that no such steps may be taken that would have a material adverse effect on the Unitholders holding Common Units represented by Common Unit Certificates.

Section 6.8 Special Provisions Relating to the Holders of Incentive Distribution Rights.

Notwithstanding anything to the contrary set forth in this Agreement, the holders of the Incentive Distribution Rights (a) shall (i) possess the rights and obligations provided in this Agreement with respect to a Limited Partner pursuant to Articles III and VII and (ii) have a Capital Account as a Partner pursuant to Section 5.5 and all other provisions related thereto and (b) shall not (i) be entitled to vote on any matters requiring the approval or vote of the holders of Outstanding Units, (ii) be entitled to any distributions other than as provided in Sections 6.4(a)(v), (vi) and (vii), 6.4(b)(iii), (iv) and (v), and 12.4 or (iii) be allocated items of income, gain, loss or deduction other than as specified in this Article VI.

Section 6.9 Entity-Level Taxation.

If legislation is enacted or the interpretation of existing language is modified by the relevant governmental authority which causes a Group Member to be treated as an association taxable as a corporation or otherwise subjects a Group Member to entity-level taxation for

federal, state or local income tax purposes, the then applicable Minimum Quarterly Distribution, First Target Distribution, Second Target Distribution and Third Target Distribution, shall be adjusted to equal the product obtained by multiplying (a) the amount thereof by (b) one minus the sum of (i) the highest marginal federal corporate (or other entity, as applicable) income tax rate of the Group Member for the taxable year of the Group Member in which such Quarter occurs (expressed as a percentage) plus (ii) the effective overall state and local income tax rate (expressed as a percentage) applicable to the Group Member for the calendar year next preceding the calendar year in which such Quarter occurs (after taking into account the benefit of any deduction allowable for federal income tax purposes with respect to the payment of state and local income taxes), but only to the extent of the increase in such rates resulting from such legislation or interpretation. Such effective overall state and local income tax rate shall be determined for the taxable year next preceding the first taxable year during which the Group Member is taxable for federal income tax purposes as an association taxable as a corporation or is otherwise subject to entity-level taxation by determining such rate as if the Group Member had been subject to such state and local taxes during such preceding taxable year.

ARTICLE VII

MANAGEMENT AND OPERATION OF BUSINESS

Section 7.1 Management.

(a) The General Partner shall conduct, direct and manage all activities of the Partnership. Except as otherwise expressly provided in this Agreement, all management powers over the business and affairs of the Partnership shall be exclusively vested in the General Partner, and no Limited Partner or Assignee shall have any management power over the business and affairs of the Partnership. In addition to the powers now or hereafter granted a general partner of a limited partnership under applicable law or which are granted to the General Partner under any other provision of this Agreement, the General Partner, subject to Section 7.3, shall have full power and authority to do all things and on such terms as it, in its sole discretion, may deem necessary or appropriate to conduct the business of the Partnership, to exercise all powers set forth in Section 2.5 and to effectuate the purposes set forth in Section 2.4, including the following:

(i) the making of any expenditures, the lending or borrowing of money, the assumption or guarantee of, or other contracting for, indebtedness and other liabilities, the issuance of evidences of indebtedness, including indebtedness that is convertible into Partnership Securities, and the incurring of any other obligations;

(ii) the making of tax, regulatory and other filings, or rendering of periodic or other reports to governmental or other agencies having jurisdiction over the business or assets of the Partnership;

(iii) the acquisition, disposition, mortgage, pledge, encumbrance, hypothecation or exchange of any or all of the assets of the Partnership or the merger or

other combination of the Partnership with or into another Person (the matters described in this clause (iii) being subject, however, to any prior approval that may be required by Section 7.3);

(iv) the use of the assets of the Partnership (including cash on hand) for any purpose consistent with the terms of this Agreement, including the financing of the conduct of the operations of the Partnership Group; subject to Section 7.6(a), the lending of funds to other Persons (including other Group Members); the repayment or guarantee of obligations of the Partnership Group; and the making of capital contributions to any member of the Partnership Group;

(v) the negotiation, execution and performance of any contracts, conveyances or other instruments (including instruments that limit the liability of the Partnership under contractual arrangements to all or particular assets of the Partnership, with the other party to the contract to have no recourse against the General Partner or its assets other than its interest in the Partnership, even if same results in the terms of the transaction being less favorable to the Partnership than would otherwise be the case);

(vi) the distribution of Partnership cash;

(vii) the selection and dismissal of employees (including employees having titles such as “president,” “vice president,” “secretary” and “treasurer”) and agents, outside attorneys, accountants, consultants and contractors and the determination of their compensation and other terms of employment or hiring;

(viii) the maintenance of such insurance for the benefit of the Partnership Group and the Partners as it deems necessary or appropriate;

(ix) the formation of, or acquisition of an interest in, and the contribution of property and the making of loans to, any further limited or general partnerships, joint ventures, corporations, limited liability companies or other relationships (including the acquisition of interests in, and the contributions of property to, any Group Member from time to time) subject to the restrictions set forth in Section 2.4;

(x) the control of any matters affecting the rights and obligations of the Partnership, including the bringing and defending of actions at law or in equity and otherwise engaging in the conduct of litigation and the incurring of legal expense and the settlement of claims and litigation;

(xi) the indemnification of any Person against liabilities and contingencies to the extent permitted by law;

(xii) the entering into of listing agreements with any National Securities Exchange and the delisting of some or all of the Limited Partner Interests from, or

requesting that trading be suspended on, any such exchange (subject to any prior approval that may be required under Section 4.8);

(xiii) unless restricted or prohibited by Section 5.7, the purchase, sale or other acquisition or disposition of Partnership Securities, or the issuance of additional options, rights, warrants and appreciation rights relating to Partnership Securities; and

(xiv) the undertaking of any action in connection with the Partnership’s participation in any Group Member as a member or partner.

(b) Notwithstanding any other provision of this Agreement, the Operating Company Agreement, the Delaware Act or any applicable law, rule or regulation, each of the Partners and the Assignees and each other Person who may acquire an interest in Partnership Securities hereby (i) approves, ratifies and confirms the execution, delivery and performance by the parties thereto of the Underwriting Agreement, the Omnibus Agreement, the Contribution Agreement, the Operating Company Agreement, any other limited liability company or partnership agreement of any other Group Member and the other agreements described in or filed as exhibits to the Registration Statement that are related to the transactions contemplated by the Registration Statement; (ii) agrees that the General Partner (on its own or through any officer of the Partnership) is authorized to execute, deliver and perform the agreements referred to in clause (i) of this sentence and the other agreements, acts, transactions and matters described in or contemplated by the Registration Statement on behalf of the Partnership without any further act, approval or vote of the Partners or the Assignees or the other Persons who may acquire an interest in Partnership Securities; and (iii) agrees that the execution, delivery or performance by the General Partner, any Group Member or any Affiliate of any of them, of this Agreement or any agreement authorized or permitted under this Agreement (including the exercise by the General Partner or any Affiliate of the General Partner of the rights accorded pursuant to Article XV), shall not constitute a breach by the General Partner of any duty that the General Partner may owe the Partnership or the Limited Partners or any other Persons under this Agreement (or any other agreements) or of any duty stated or implied by law or equity.

Section 7.2 Certificate of Limited Partnership.

The General Partner has caused the Certificate of Limited Partnership to be filed with the Secretary of State of the State of Delaware as required by the Delaware Act. The General Partner shall use all reasonable efforts to cause to be filed such other certificates or documents as may be determined by the General Partner in its sole discretion to be reasonable and necessary or appropriate for the formation, continuation, qualification and operation of a limited partnership (or a partnership in which the limited partners have limited liability) in the State of Delaware or any other state in which the Partnership may elect to do business or own property. To the extent that such action is determined by the General Partner in its sole discretion to be reasonable and necessary or appropriate, the General Partner shall file amendments to and restatements of the Certificate of Limited Partnership and do all things to maintain the Partnership as a limited partnership (or a partnership or other entity in which the limited partners have limited liability) under the laws of the State of Delaware or of any other state in which the Partnership may elect

to do business or own property. Subject to the terms of Section 3.4(a), the General Partner shall not be required, before or after filing, to deliver or mail a copy of the Certificate of Limited Partnership, any qualification document or any amendment thereto to any Limited Partner.

Section 7.3 Restrictions on the General Partner’s Authority.

(a) The General Partner may not, without written approval of the specific act by holders of all of the Outstanding Limited Partner Interests or by other written instrument executed and delivered by holders of all of the Outstanding Limited Partner Interests subsequent to the date of this Agreement, take any action in contravention of this Agreement, including, except as otherwise provided in this Agreement, (i) committing any act that would make it impossible to carry on the ordinary business of the Partnership; (ii) possessing Partnership property, or assigning any rights in specific Partnership property, for other than a Partnership purpose; (iii) admitting a Person as a Partner; (iv) amending this Agreement in any manner; or (v) transferring its interest as a general partner of the Partnership.

(b) Except as provided in Articles XII and XIV, the General Partner may not sell, exchange or otherwise dispose of all or substantially all of the Partnership’s assets in a single transaction or a series of related transactions (including by way of merger, consolidation or other combination) or approve on behalf of the Partnership the sale, exchange or other disposition of all or substantially all of the assets of the Operating Company and its subsidiaries taken as a whole without the approval of holders of a Unit Majority; provided however that this provision shall not preclude or limit the General Partner’s ability to mortgage, pledge, hypothecate or grant a security interest in all or substantially all of the assets of the Partnership or the Operating Company and shall not apply to any forced sale of any or all of the assets of the Partnership or the Operating Company pursuant to the foreclosure of, or other realization upon, any such encumbrance. Without the approval of holders of a Unit Majority, the General Partner shall not, on behalf of the Partnership, (i) consent to any amendment to the Operating Company Agreement or, except as expressly permitted by Section 7.9(d), take any action permitted to be taken by a member of the Operating Company, in either case, that would adversely affect the Limited Partners (including any particular class of Partnership Interests as compared to any other class of Partnership Interests) in any material respect or (ii) except as permitted under Sections 4.6, 11.1 and 11.2, elect or cause the Partnership to elect a successor general partner of the Partnership.

Section 7.4 Reimbursement of the General Partner.

(a) Except as provided in this Section 7.4 and elsewhere in this Agreement, the General Partner shall not be compensated for its services as a general partner or managing member of any Group Member.

(b) The General Partner shall be reimbursed on a monthly basis, or such other reasonable basis as the General Partner may determine in its sole discretion, for (i) all direct and indirect expenses it incurs or payments it makes on behalf of the Partnership (including salary, bonus, incentive compensation and other amounts paid to any Person including Affiliates of the

General Partner to perform services for the Partnership or for the General Partner in the discharge of its duties to the Partnership), and (ii) all other necessary or appropriate expenses allocable to the Partnership or otherwise reasonably incurred by the General Partner in connection with operating the Partnership’s business (including expenses allocated to the General Partner by its Affiliates). The General Partner shall determine the expenses that are allocable to the Partnership in any reasonable manner determined by the General Partner in its sole discretion. Reimbursements pursuant to this Section 7.4 shall be in addition to any reimbursement to the General Partner as a result of indemnification pursuant to Section 7.7.

(c) Subject to Section 5.7, the General Partner, in its sole discretion and without the approval of the Limited Partners (who shall have no right to vote in respect thereof), may propose and adopt on behalf of the Partnership employee benefit plans, employee programs and employee practices (including plans, programs and practices involving the issuance of Partnership Securities or options to purchase or rights, warrants or appreciation rights relating to Partnership Securities), or cause the Partnership to issue Partnership Securities in connection with, or pursuant to, any employee benefit plan, employee program or employee practice maintained or sponsored by the General Partner or any of its Affiliates, in each case for the benefit of employees of the General Partner, any Group Member or any Affiliate, or any of them, in respect of services performed, directly or indirectly, for the benefit of the Partnership Group. The Partnership agrees to issue and sell to the General Partner or any of its Affiliates any Partnership Securities that the General Partner or such Affiliates are obligated to provide to any employees pursuant to any such employee benefit plans, employee programs or employee practices. Expenses incurred by the General Partner in connection with any such plans, programs and practices (including the net cost to the General Partner or such Affiliates of Partnership Securities purchased by the General Partner or such Affiliates from the Partnership to fulfill options or awards under such plans, programs and practices) shall be reimbursed in accordance with Section 7.4(b). Any and all obligations of the General Partner under any employee benefit plans, employee programs or employee practices adopted by the General Partner as permitted by this Section 7.4(c) shall constitute obligations of the General Partner hereunder and shall be assumed by any successor General Partner approved pursuant to Section 11.1 or 11.2 or the transferee of or successor to all of the General Partner’s General Partner Interest pursuant to Section 4.6.

Section 7.5 Outside Activities.

(a) After the Closing Date, the General Partner, for so long as it is the General Partner of the Partnership (i) agrees that its sole business will be to act as a general partner or managing member, as the case may be, of the Partnership and any other partnership or limited liability company of which the Partnership or the Operating Company is, directly or indirectly, a partner or member and to undertake activities that are ancillary or related thereto (including being a limited partner in the Partnership), (ii) shall not engage in any business or activity or incur any debts or liabilities except in connection with or incidental to (A) its performance as general partner or managing member of one or more Group Members or as described in or contemplated by the Registration Statement or (B) the acquiring, owning or disposing of debt or

equity securities in any Group Member and (iii) except to the extent permitted in the Omnibus Agreement, shall not, and shall cause its Affiliates not to, engage in any Restricted Business.

(b) MarkWest Hydrocarbon, Inc. and certain of its Affiliates have entered into the Omnibus Agreement, which agreement sets forth certain restrictions on the ability of MarkWest Hydrocarbon, Inc. and its Affiliates to engage in Restricted Businesses.

(c) Except as specifically restricted by Section 7.5(a) and the Omnibus Agreement, each Indemnitee (other than the General Partner) shall have the right to engage in businesses of every type and description and other activities for profit and to engage in and possess an interest in other business ventures of any and every type or description, whether in businesses engaged in or anticipated to be engaged in by any Group Member, independently or with others, including business interests and activities in direct competition with the business and activities of any Group Member, and none of the same shall constitute a breach of this Agreement or any duty express or implied by law to any Group Member or any Partner or Assignee. Neither any Group Member, any Limited Partner nor any other Person shall have any rights by virtue of this Agreement, the Operating Company Agreement, the limited liability company or partnership agreements of any other Group Member or the partnership relationship established hereby in any business ventures of any Indemnitee.

(d) Subject to the terms of Section 7.5(a), Section 7.5(b), Section 7.5(c) and the Omnibus Agreement, but otherwise notwithstanding anything to the contrary in this Agreement, (i) the engaging in competitive activities by any Indemnitees (other than the General Partner) in accordance with the provisions of this Section 7.5 is hereby approved by the Partnership and all Partners, (ii) it shall be deemed not to be a breach of the General Partner’s fiduciary duty or any other obligation of any type whatsoever of the General Partner for the Indemnitees (other than the General Partner) to engage in such business interests and activities in preference to or to the exclusion of the Partnership and (iii) except as set forth in the Omnibus Agreement, the General Partner and the Indemnitees shall have no obligation to present business opportunities to the Partnership.

(e) The General Partner and any of its Affiliates may acquire Units or other Partnership Securities in addition to those acquired on the Closing Date and, except as otherwise provided in this Agreement, shall be entitled to exercise all rights of the General Partner or Limited Partner, as applicable, relating to such Units or Partnership Securities.

(f) The term “Affiliates” when used in Section 7.5(a) and Section 7.5(e) with respect to the General Partner shall not include any Group Member or any Subsidiary of the Group Member.

(g) Anything in this Agreement to the contrary notwithstanding, to the extent that provisions of Sections 7.7, 7.8, 7.9, 7.10 or other Sections of this Agreement purport or are interpreted to have the effect of restricting the fiduciary duties that might otherwise, as a result of Delaware or other applicable law, be owed by the General Partner to the Partnership and its Limited Partners, or to constitute a waiver or consent by the Limited Partners to any such

restriction, such provisions shall be inapplicable and have no effect in determining whether the General Partner has complied with its fiduciary duties in connection with determinations made by it under this Section 7.5.

Section 7.6 Loans from the General Partner; Loans or Contributions from the Partnership; Contracts with Affiliates; Certain Restrictions on the General Partner.

(a) The General Partner or any of its Affiliates may lend to any Group Member, and any Group Member may borrow from the General Partner or any of its Affiliates, funds needed or desired by the Group Member for such periods of time and in such amounts as the General Partner may determine; provided, however, that in any such case the lending party may not charge the borrowing party interest at a rate greater than the rate that would be charged the borrowing party or impose terms less favorable to the borrowing party than would be charged or imposed on the borrowing party by unrelated lenders on comparable loans made on an arm’s-length basis (without reference to the lending party’s financial abilities or guarantees). The borrowing party shall reimburse the lending party for any costs (other than any additional interest costs) incurred by the lending party in connection with the borrowing of such funds. For purposes of this Section 7.6(a) and Section 7.6(b), the term “Group Member” shall include any Affiliate of a Group Member that is controlled by the Group Member. No Group Member may lend funds to the General Partner or any of its Affiliates (other than another Group Member).

(b) The Partnership may lend or contribute to any Group Member, and any Group Member may borrow from the Partnership, funds on terms and conditions established in the sole discretion of the General Partner; provided, however, that the Partnership may not charge the Group Member interest at a rate less than the rate that would be charged to the Group Member (without reference to the General Partner’s financial abilities or guarantees) by unrelated lenders on comparable loans. The foregoing authority shall be exercised by the General Partner in its sole discretion and shall not create any right or benefit in favor of any Group Member or any other Person.

(c) The General Partner may itself, or may enter into an agreement with any of its Affiliates to, render services to a Group Member or to the General Partner in the discharge of its duties as General Partner of the Partnership. Any services rendered to a Group Member by the General Partner or any of its Affiliates shall be on terms that are fair and reasonable to the Partnership; provided, however, that the requirements of this Section 7.6(c) shall be deemed satisfied as to (i) any transaction approved by Special Approval, (ii) any transaction, the terms of which are no less favorable to the Partnership Group than those generally being provided to or available from unrelated third parties or (iii) any transaction that, taking into account the totality of the relationships between the parties involved (including other transactions that may be particularly favorable or advantageous to the Partnership Group), is equitable to the Partnership Group. The provisions of Section 7.4 shall apply to the rendering of services described in this Section 7.6(c).

(d) The Partnership Group may transfer assets to joint ventures, other partnerships, corporations, limited liability companies or other business entities in which it is or thereby becomes a participant upon such terms and subject to such conditions as are consistent with this Agreement and applicable law.

(e) Neither the General Partner nor any of its Affiliates shall sell, transfer or convey any property to, or purchase any property from, the Partnership, directly or indirectly, except pursuant to transactions that are fair and reasonable to the Partnership; provided, however, that the requirements of this Section 7.6(e) shall be deemed to be satisfied as to (i) the transactions effected pursuant to Sections 5.2 and 5.3, the Contribution Agreement and any other transactions described in or contemplated by the Registration Statement, (ii) any transaction approved by Special Approval, (iii) any transaction, the terms of which are no less favorable to the Partnership than those generally being provided to or available from unrelated third parties, or (iv) any transaction that, taking into account the totality of the relationships between the parties involved (including other transactions that may be particularly favorable or advantageous to the Partnership), is equitable to the Partnership. With respect to any contribution of assets to the Partnership in exchange for Partnership Securities, the Conflicts Committee, in determining whether the appropriate number of Partnership Securities are being issued, may take into account, among other things, the fair market value of the assets, the liquidated and contingent liabilities assumed, the tax basis in the assets, the extent to which tax-only allocations to the transferor will protect the existing partners of the Partnership against a low tax basis, and such other factors as the Conflicts Committee deems relevant under the circumstances.

(f) The General Partner and its Affiliates will have no obligation to permit any Group Member to use any facilities or assets of the General Partner and its Affiliates, except as may be provided in contracts entered into from time to time specifically dealing with such use, nor shall there be any obligation on the part of the General Partner or its Affiliates to enter into such contracts.

(g) Without limitation of Sections 7.6(a) through 7.6(f), and notwithstanding anything to the contrary in this Agreement, the existence of the conflicts of interest described in the Registration Statement are hereby approved by all Partners.

Section 7.7 Indemnification.

(a) To the fullest extent permitted by law but subject to the limitations expressly provided in this Agreement, all Indemnitees shall be indemnified and held harmless by the Partnership from and against any and all losses, claims, damages, liabilities, joint or several, expenses (including legal fees and expenses), judgments, fines, penalties, interest, settlements or other amounts arising from any and all claims, demands, actions, suits or proceedings, whether civil, criminal, administrative or investigative, in which any Indemnitee may be involved, or is threatened to be involved, as a party or otherwise, by reason of its status as an Indemnitee; provided, that in each case the Indemnitee acted in good faith and in a manner that such Indemnitee reasonably believed to be in, or (in the case of a Person other than the General Partner) not opposed to, the best interests of the Partnership and, with respect to any criminal

proceeding, had no reasonable cause to believe its conduct was unlawful; provided, further, no indemnification pursuant to this Section 7.7 shall be available to the General Partner of its Affiliates (other than a Group Member) with respect to its or their obligations incurred pursuant to the Underwriting Agreement or the Contribution Agreement (other than obligations incurred by the General Partner on behalf of the Partnership). The termination of any action, suit or proceeding by judgment, order, settlement, conviction or upon a plea of nolo contendere, or its equivalent, shall not create a presumption that the Indemnitee acted in a manner contrary to that specified above. Any indemnification pursuant to this Section 7.7 shall be made only out of the assets of the Partnership, it being agreed that the General Partner shall not be personally liable for such indemnification and shall have no obligation to contribute or loan any monies or property to the Partnership to enable it to effectuate such indemnification.

(b) To the fullest extent permitted by law, expenses (including legal fees and expenses) incurred by an Indemnitee who is indemnified pursuant to Section 7.7(a) in defending any claim, demand, action, suit or proceeding shall, from time to time, be advanced by the Partnership prior to the final disposition of such claim, demand, action, suit or proceeding upon receipt by the Partnership of any undertaking by or on behalf of the Indemnitee to repay such amount if it shall be determined that the Indemnitee is not entitled to be indemnified as authorized in this Section 7.7.

(c) The indemnification provided by this Section 7.7 shall be in addition to any other rights to which an Indemnitee may be entitled under any agreement, pursuant to any vote of the holders of Outstanding Limited Partner Interests, as a matter of law or otherwise, both as to actions in the Indemnitee’s capacity as an Indemnitee and as to actions in any other capacity (including any capacity under the Underwriting Agreement), and shall continue as to an Indemnitee who has ceased to serve in such capacity and shall inure to the benefit of the heirs, successors, assigns and administrators of the Indemnitee.

(d) The Partnership may purchase and maintain (or reimburse the General Partner or its Affiliates for the cost of) insurance, on behalf of the General Partner, its Affiliates and such other Persons as the General Partner shall determine, against any liability that may be asserted against or expense that may be incurred by such Person in connection with the Partnership’s activities or such Person’s activities on behalf of the Partnership, regardless of whether the Partnership would have the power to indemnify such Person against such liability under the provisions of this Agreement.

(e) For purposes of this Section 7.7, the Partnership shall be deemed to have requested an Indemnitee to serve as fiduciary of an employee benefit plan whenever the performance by it of its duties to the Partnership also imposes duties on, or otherwise involves services by, it to the plan or participants or beneficiaries of the plan; excise taxes assessed on an Indemnitee with respect to an employee benefit plan pursuant to applicable law shall constitute “fines” within the meaning of Section 7.7(a); and action taken or omitted by it with respect to any employee benefit plan in the performance of its duties for a purpose reasonably believed by it to be in the interest of the participants and beneficiaries of the plan shall be deemed to be for a purpose which is in, or not opposed to, the best interests of the Partnership.

(f) In no event may an Indemnitee subject the Limited Partners to personal liability by reason of the indemnification provisions set forth in this Agreement.

(g) An Indemnitee shall not be denied indemnification in whole or in part under this Section 7.7 because the Indemnitee had an interest in the transaction with respect to which the indemnification applies if the transaction was otherwise permitted by the terms of this Agreement.

(h) The provisions of this Section 7.7 are for the benefit of the Indemnitees, their heirs, successors, assigns and administrators and shall not be deemed to create any rights for the benefit of any other Persons.

(i) No amendment, modification or repeal of this Section 7.7 or any provision hereof shall in any manner terminate, reduce or impair the right of any past, present or future Indemnitee to be indemnified by the Partnership, nor the obligations of the Partnership to indemnify any such Indemnitee under and in accordance with the provisions of this Section 7.7 as in effect immediately prior to such amendment, modification or repeal with respect to claims arising from or relating to matters occurring, in whole or in part, prior to such amendment, modification or repeal, regardless of when such claims may arise or be asserted.

Section 7.8 Liability of Indemnitees.

(a) Notwithstanding anything to the contrary set forth in this Agreement, no Indemnitee shall be liable for monetary damages to the Partnership, the Limited Partners, the Assignees or any other Persons who have acquired interests in the Partnership Securities, for losses sustained or liabilities incurred as a result of any act or omission if such Indemnitee acted in good faith.

(b) Subject to its obligations and duties as General Partner set forth in Section 7.1(a), the General Partner may exercise any of the powers granted to it by this Agreement and perform any of the duties imposed upon it hereunder either directly or by or through its agents, and the General Partner shall not be responsible for any misconduct or negligence on the part of any such agent appointed by the General Partner in good faith.

(c) To the extent that, at law or in equity, an Indemnitee has duties (including fiduciary duties) and liabilities relating thereto to the Partnership or to the Partners, the General Partner and any other Indemnitee acting in connection with the Partnership’s business or affairs shall not be liable to the Partnership or to any Partner for its good faith reliance on the provisions of this Agreement. The provisions of this Agreement, to the extent that they restrict or otherwise modify the duties and liabilities of an Indemnitee otherwise existing at law or in equity, are agreed by the Partners to replace such other duties and liabilities of such Indemnitee.

(d) Any amendment, modification or repeal of this Section 7.8 or any provision hereof shall be prospective only and shall not in any way affect the limitations on the liability to the Partnership, the Limited Partners, the General Partner, and the Partnership’s and General

Partner’s directors, officers and employees under this Section 7.8 as in effect immediately prior to such amendment, modification or repeal with respect to claims arising from or relating to matters occurring, in whole or in part, prior to such amendment, modification or repeal, regardless of when such claims may arise or be asserted.

Section 7.9 Resolution of Conflicts of Interest.

(a) Unless otherwise expressly provided in this Agreement, the Operating Company Agreement or the limited liability company or partnership agreement of any other Group Member whenever a potential conflict of interest exists or arises between the General Partner or any of its Affiliates, on the one hand, and the Partnership, the Operating Company, any other Group Member, any Partner or any Assignee, on the other, any resolution or course of action by the General Partner or its Affiliates in respect of such conflict of interest shall be permitted and deemed approved by all Partners, and shall not constitute a breach of this Agreement, of the Operating Company Agreement, of any agreement contemplated herein or therein, or of any duty stated or implied by law or equity, if the resolution or course of action is, or by operation of this Agreement is deemed to be, fair and reasonable to the Partnership. The General Partner shall be authorized but not required in connection with its resolution of such conflict of interest to seek Special Approval of such resolution. Any conflict of interest and any resolution of such conflict of interest shall be conclusively deemed fair and reasonable to the Partnership if such conflict of interest or resolution is (i) approved by Special Approval (as long as the material facts known to the General Partner or any of its Affiliates regarding any proposed transaction were disclosed to the Conflicts Committee at the time it gave its approval), (ii) on terms no less favorable to the Partnership than those generally being provided to or available from unrelated third parties or (iii) fair to the Partnership, taking into account the totality of the relationships between the parties involved (including other transactions that may be particularly favorable or advantageous to the Partnership). The General Partner may also adopt a resolution or course of action that has not received Special Approval. The General Partner (including the Conflicts Committee in connection with Special Approval) shall be authorized in connection with its determination of what is “fair and reasonable” to the Partnership and in connection with its resolution of any conflict of interest to consider (A) the relative interests of any party to such conflict, agreement, transaction or situation and the benefits and burdens relating to such interest; (B) any customary or accepted industry practices and any customary or historical dealings with a particular Person; (C) any applicable generally accepted accounting practices or principles; and (D) such additional factors as the General Partner (including the Conflicts Committee) determines in its sole discretion to be relevant, reasonable or appropriate under the circumstances. Nothing contained in this Agreement, however, is intended to nor shall it be construed to require the General Partner (including the Conflicts Committee) to consider the interests of any Person other than the Partnership. In the absence of bad faith by the General Partner, the resolution, action or terms so made, taken or provided by the General Partner with respect to such matter shall not constitute a breach of this Agreement or any other agreement contemplated herein or a breach of any standard of care or duty imposed herein or therein or, to the extent permitted by law, under the Delaware Act or any other law, rule or regulation.

(b) Whenever this Agreement or any other agreement contemplated hereby provides that the General Partner or any of its Affiliates is permitted or required to make a decision (i) in its “sole discretion” or “discretion,” that it deems “necessary or appropriate” or “necessary or advisable” or under a grant of similar authority or latitude, except as otherwise provided herein, the General Partner or such Affiliate shall be entitled to consider only such interests and factors as it desires and shall have no duty or obligation to give any consideration to any interest of, or factors affecting, the Partnership, any other Group Member, any Limited Partner or any Assignee, (ii) it may make such decision in its sole discretion (regardless of whether there is a reference to “sole discretion” or “discretion”) unless another express standard is provided for, or (iii) in “good faith” or under another express standard, the General Partner or such Affiliate shall act under such express standard and shall not be subject to any other or different standards imposed by this Agreement, the Operating Company Agreement, the limited liability company or partnership agreement of any other Group Member, any other agreement contemplated hereby or under the Delaware Act or any other law, rule or regulation. In addition, any actions taken by the General Partner or such Affiliate consistent with the standards of “reasonable discretion” set forth in the definitions of Available Cash or Operating Surplus shall not constitute a breach of any duty of the General Partner to the Partnership or the Limited Partners. The General Partner shall have no duty, express or implied, to sell or otherwise dispose of any asset of the Partnership Group other than in the ordinary course of business. No borrowing by any Group Member or the approval thereof by the General Partner shall be deemed to constitute a breach of any duty of the General Partner to the Partnership or the Limited Partners by reason of the fact that the purpose or effect of such borrowing is directly or indirectly to (A) enable distributions to the General Partner or its Affiliates (including in their capacities as Limited Partners) to exceed 2% of the total amount distributed to all partners or (B) hasten the expiration of the Subordination Period or the conversion of any Subordinated Units into Common Units.

(c) Whenever a particular transaction, arrangement or resolution of a conflict of interest is required under this Agreement to be “fair and reasonable” to any Person, the fair and reasonable nature of such transaction, arrangement or resolution shall be considered in the context of all similar or related transactions.

(d) The Unitholders hereby authorize the General Partner, on behalf of the Partnership as a partner or member of a Group Member, to approve of actions by the general partner or managing member of such Group Member similar to those actions permitted to be taken by the General Partner pursuant to this Section 7.9.

Section 7.10 Other Matters Concerning the General Partner.

(a) The General Partner may rely and shall be protected in acting or refraining from acting upon any resolution, certificate, statement, instrument, opinion, report, notice, request, consent, order, bond, debenture or other paper or document believed by it to be genuine and to have been signed or presented by the proper party or parties.

(b) The General Partner may consult with legal counsel, accountants, appraisers, management consultants, investment bankers and other consultants and advisers selected by it,

and any act taken or omitted to be taken in reliance upon the opinion (including an Opinion of Counsel) of such Persons as to matters that the General Partner reasonably believes to be within such Person’s professional or expert competence shall be conclusively presumed to have been done or omitted in good faith and in accordance with such opinion.

(c) The General Partner shall have the right, in respect of any of its powers or obligations hereunder, to act through any of its duly authorized officers, a duly appointed attorney or attorneys-in-fact or the duly authorized officers of the Partnership.

(d) Any standard of care and duty imposed by this Agreement or under the Delaware Act or any applicable law, rule or regulation shall be modified, waived or limited, to the extent permitted by law, as required to permit the General Partner to act under this Agreement or any other agreement contemplated by this Agreement and to make any decision pursuant to the authority prescribed in this Agreement, so long as such action is reasonably believed by the General Partner to be in, or not inconsistent with, the best interests of the Partnership.

Section 7.11 Purchase or Sale of Partnership Securities.

The General Partner may cause the Partnership to purchase or otherwise acquire Partnership Securities; provided that, except as permitted pursuant to Section 4.10, the General Partner may not cause any Group Member to purchase Subordinated Units during the Subordination Period. As long as Partnership Securities are held by any Group Member, such Partnership Securities shall not be considered Outstanding for any purpose, except as otherwise provided herein. The General Partner or any Affiliate of the General Partner may also purchase or otherwise acquire and sell or otherwise dispose of Partnership Securities for its own account, subject to the provisions of Articles IV and X.

Section 7.12 Registration Rights of the General Partner and its Affiliates.

(a) If (i) the General Partner or any Affiliate of the General Partner or of MarkWest Hydrocarbon, Inc. (including for purposes of this Section 7.12, any Person that is an Affiliate of the General Partner or MarkWest Hydrocarbon Inc. at the date hereof notwithstanding that it may later cease to be an Affiliate of the General Partner or MarkWest Hydrocarbon, Inc.) holds Partnership Securities that it desires to sell and (ii) Rule 144 of the Securities Act (or any successor rule or regulation to Rule 144) or another exemption from registration is not available to enable such holder of Partnership Securities (the “Holder”) to dispose of the number of Partnership Securities it desires to sell at the time it desires to do so without registration under the Securities Act, then upon the request of the General Partner or any of its or MarkWest Hydrocarbon’s Affiliates, the Partnership shall file with the Commission as promptly as practicable after receiving such request, and use all reasonable efforts to cause to become effective and remain effective for a period of not less than six months following its effective date or such shorter period as shall terminate when all Partnership Securities covered by such registration statement have been sold, a registration statement under the Securities Act registering the offering and sale of the number of Partnership Securities specified by the Holder; provided, however, that the Partnership shall not be required to effect more than three

registrations pursuant to this Section 7.12(a); and provided further, however, that if the Conflicts Committee determines in its good faith judgment that a postponement of the requested registration for up to six months would be in the best interests of the Partnership and its Partners due to a pending transaction, investigation or other event, the filing of such registration statement or the effectiveness thereof may be deferred for up to six months, but not thereafter. In connection with any registration pursuant to the immediately preceding sentence, the Partnership shall promptly prepare and file (x) such documents as may be necessary to register or qualify the securities subject to such registration under the securities laws of such states as the Holder shall reasonably request; provided, however, that no such qualification shall be required in any jurisdiction where, as a result thereof, the Partnership would become subject to general service of process or to taxation or qualification to do business as a foreign corporation or partnership doing business in such jurisdiction solely as a result of such registration, and (y) such documents as may be necessary to apply for listing or to list the Partnership Securities subject to such registration on such National Securities Exchange as the Holder shall reasonably request, and do any and all other acts and things that may reasonably be necessary or advisable to enable the Holder to consummate a public sale of such Partnership Securities in such states. Except as set forth in Section 7.12(c), all costs and expenses of any such registration and offering (other than the underwriting discounts and commissions) shall be paid by the Partnership, without reimbursement by the Holder.

(b) If the Partnership shall at any time propose to file a registration statement under the Securities Act for an offering of equity securities of the Partnership for cash (other than an offering relating solely to an employee benefit plan), the Partnership shall use all reasonable efforts to include such number or amount of securities held by the Holder in such registration statement as the Holder shall request. If the proposed offering pursuant to this Section 7.12(b) shall be an underwritten offering, then, in the event that the managing underwriter or managing underwriters of such offering advise the Partnership and the Holder in writing that in their opinion the inclusion of all or some of the Holder’s Partnership Securities would adversely and materially affect the success of the offering, the Partnership shall include in such offering only that number or amount, if any, of securities held by the Holder which, in the opinion of the managing underwriter or managing underwriters, will not so adversely and materially affect the offering. Except as set forth in Section 7.12(c), all costs and expenses of any such registration and offering (other than the underwriting discounts and commissions) shall be paid by the Partnership, without reimbursement by the Holder.

(c) If underwriters are engaged in connection with any registration referred to in this Section 7.12, the Partnership shall provide indemnification, representations, covenants, opinions and other assurance to the underwriters in form and substance reasonably satisfactory to such underwriters. Further, in addition to and not in limitation of the Partnership’s obligation under Section 7.7, the Partnership shall, to the fullest extent permitted by law, indemnify and hold harmless the Holder, its officers, directors and each Person who controls the Holder (within the meaning of the Securities Act) and any agent thereof (collectively, “Indemnified Persons”) against any losses, claims, demands, actions, causes of action, assessments, damages, liabilities (joint or several), costs and expenses (including interest, penalties and reasonable attorneys’ fees

and disbursements), resulting to, imposed upon, or incurred by the Indemnified Persons, directly or indirectly, under the Securities Act or otherwise (hereinafter referred to in this Section 7.12(c) as a “claim” and in the plural as “claims”) based upon, arising out of or resulting from any untrue statement or alleged untrue statement of any material fact contained in any registration statement under which any Partnership Securities were registered under the Securities Act or any state securities or Blue Sky laws, in any preliminary prospectus (if used prior to the effective date of such registration statement), or in any summary or final prospectus or in any amendment or supplement thereto (if used during the period the Partnership is required to keep the registration statement current), or arising out of, based upon or resulting from the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements made therein not misleading; provided, however, that the Partnership shall not be liable to any Indemnified Person to the extent that any such claim arises out of, is based upon or results from an untrue statement or alleged untrue statement or omission or alleged omission made in such registration statement, such preliminary, summary or final prospectus or such amendment or supplement, in reliance upon and in conformity with written information furnished to the Partnership by or on behalf of such Indemnified Person specifically for use in the preparation thereof.

(d) The provisions of Section 7.12(a) and 7.12(b) shall continue to be applicable with respect to the General Partner (and any of the General Partner’s or MarkWest Hydrocarbon, Inc.’s Affiliates) after it ceases to be a Partner of the Partnership, during a period of two years subsequent to the effective date of such cessation and for so long thereafter as is required for the Holder to sell all of the Partnership Securities with respect to which it has requested during such two-year period inclusion in a registration statement otherwise filed or that a registration statement be filed; provided, however, that the Partnership shall not be required to file successive registration statements covering the same Partnership Securities for which registration was demanded during such two-year period. The provisions of Section 7.12(c) shall continue in effect thereafter.

(e) Any request to register Partnership Securities pursuant to this Section 7.12 shall (i) specify the Partnership Securities intended to be offered and sold by the Person making the request, (ii) express such Person’s present intent to offer such Partnership Securities for distribution, (iii) describe the nature or method of the proposed offer and sale of Partnership Securities, and (iv) contain the undertaking of such Person to provide all such information and materials and take all action as may be required in order to permit the Partnership to comply with all applicable requirements in connection with the registration of such Partnership Securities.

Section 7.13 Reliance by Third Parties.

Notwithstanding anything to the contrary in this Agreement, any Person dealing with the Partnership shall be entitled to assume that the General Partner and any officer of the General Partner authorized by the General Partner to act on behalf of and in the name of the Partnership has full power and authority to encumber, sell or otherwise use in any manner any and all assets of the Partnership and to enter into any authorized contracts on behalf of the Partnership, and such Person shall be entitled to deal with the General Partner or any such officer as if it were the

Partnership’s sole party in interest, both legally and beneficially. Each Limited Partner hereby waives any and all defenses or other remedies that may be available against such Person to contest, negate or disaffirm any action of the General Partner or any such officer in connection with any such dealing. In no event shall any Person dealing with the General Partner or any such officer or its representatives be obligated to ascertain that the terms of the Agreement have been complied with or to inquire into the necessity or expedience of any act or action of the General Partner or any such officer or its representatives. Each and every certificate, document or other instrument executed on behalf of the Partnership by the General Partner or its representatives shall be conclusive evidence in favor of any and every Person relying thereon or claiming thereunder that (a) at the time of the execution and delivery of such certificate, document or instrument, this Agreement was in full force and effect, (b) the Person executing and delivering such certificate, document or instrument was duly authorized and empowered to do so for and on behalf of the Partnership and (c) such certificate, document or instrument was duly executed and delivered in accordance with the terms and provisions of this Agreement and is binding upon the Partnership.

ARTICLE VIII

BOOKS, RECORDS, ACCOUNTING AND REPORTS

Section 8.1 Records and Accounting.

The General Partner shall keep or cause to be kept at the principal office of the Partnership appropriate books and records with respect to the Partnership’s business, including all books and records necessary to provide to the Limited Partners any information required to be provided pursuant to Section 3.4(a). Any books and records maintained by or on behalf of the Partnership in the regular course of its business, including the record of the Record Holders and Assignees of Units or other Partnership Securities, books of account and records of Partnership proceedings, may be kept on, or be in the form of, computer disks, hard drives, punch cards, magnetic tape, photographs, micrographics or any other information storage device; provided, that the books and records so maintained are convertible into clearly legible written form within a reasonable period of time. The books of the Partnership shall be maintained, for financial reporting purposes, on an accrual basis in accordance with U.S. GAAP.

Section 8.2 Fiscal Year.

The fiscal year of the Partnership shall be a fiscal year ending December 31.

Section 8.3 Reports.

(a) As soon as practicable, but in no event later than 120 days after the close of each fiscal year of the Partnership, the General Partner shall cause to be mailed or made available to each Record Holder of a Unit as of a date selected by the General Partner in its discretion, an annual report containing financial statements of the Partnership for such fiscal year of the Partnership, presented in accordance with U.S. GAAP, including a balance sheet and statements

of operations, Partnership equity and cash flows, such statements to be audited by a firm of independent public accountants selected by the General Partner.

(b) As soon as practicable, but in no event later than 90 days after the close of each Quarter except the last Quarter of each fiscal year, the General Partner shall cause to be mailed or made available to each Record Holder of a Unit, as of a date selected by the General Partner in its discretion, a report containing unaudited financial statements of the Partnership and such other information as may be required by applicable law, regulation or rule of any National Securities Exchange on which the Units are listed for trading, or as the General Partner determines to be necessary or appropriate.

ARTICLE IX

TAX MATTERS

Section 9.1 Tax Returns and Information.

The Partnership shall timely file all returns of the Partnership that are required for federal, state and local income tax purposes on the basis of the accrual method and a taxable year ending on December 31. The tax information reasonably required by Record Holders for federal and state income tax reporting purposes with respect to a taxable year shall be furnished to them within 90 days of the close of the calendar year in which the Partnership’s taxable year ends. The classification, realization and recognition of income, gain, losses and deductions and other items shall be on the accrual method of accounting for federal income tax purposes.

Section 9.2 Tax Elections.

(a) The Partnership shall make the election under Section 754 of the Code in accordance with applicable regulations thereunder, subject to the reservation of the right to seek to revoke any such election upon the General Partner’s determination that such revocation is in the best interests of the Limited Partners. Notwithstanding any other provision herein contained, for the purposes of computing the adjustments under Section 743(b) of the Code, the General Partner shall be authorized (but not required) to adopt a convention whereby the price paid by a transferee of a Limited Partner Interest will be deemed to be the lowest quoted closing price of the Limited Partner Interests on any National Securities Exchange on which such Limited Partner Interests are traded during the calendar month in which such transfer is deemed to occur pursuant to Section 6.2(g) without regard to the actual price paid by such transferee.

(b) The Partnership shall elect to deduct expenses incurred in organizing the Partnership ratably over a sixty-month period as provided in Section 709 of the Code.

(c) Except as otherwise provided herein, the General Partner shall determine whether the Partnership should make any other elections permitted by the Code.

Section 9.3 Tax Controversies.

Subject to the provisions hereof, the General Partner is designated as the Tax Matters Partner (as defined in the Code) and is authorized and required to represent the Partnership (at the Partnership’s expense) in connection with all examinations of the Partnership’s affairs by tax authorities, including resulting administrative and judicial proceedings, and to expend Partnership funds for professional services and costs associated therewith. Each Partner agrees to cooperate with the General Partner and to do or refrain from doing any or all things reasonably required by the General Partner to conduct such proceedings.

Section 9.4 Withholding.

Notwithstanding any other provision of this Agreement, the General Partner is authorized to take any action that it determines in its discretion to be necessary or appropriate to cause the Partnership and other Group Members to comply with any withholding requirements established under the Code or any other federal, state or local law including, without limitation, pursuant to Sections 1441, 1442, 1445 and 1446 of the Code. To the extent that the Partnership is required or elects to withhold and pay over to any taxing authority any amount resulting from the allocation or distribution of income to any Partner or Assignee (including, without limitation, by reason of Section 1446 of the Code), the amount withheld may at the discretion of the General Partner be treated by the Partnership as a distribution of cash pursuant to Section 6.3 in the amount of such withholding from such Partner.

ARTICLE X

ADMISSION OF PARTNERS

Section 10.1 Admission of Initial Limited Partners.

Upon the issuance by the Partnership of Common Units, Subordinated Units and Incentive Distribution Rights to the General Partner, MarkWest Michigan, Inc. and the Underwriters as described in Sections 5.2 and 5.3 in connection with the Initial Offering, the General Partner shall admit such parties to the Partnership as Initial Limited Partners in respect of the Common Units, Subordinated Units or Incentive Distribution Rights issued to them.

Section 10.2 Admission of Substituted Limited Partner.

By transfer of a Limited Partner Interest in accordance with Article IV, the transferor shall be deemed to have given the transferee the right to seek admission as a Substituted Limited Partner subject to the conditions of, and in the manner permitted under, this Agreement. A transferor of a Certificate representing a Limited Partner Interest shall, however, only have the authority to convey to a purchaser or other transferee who does not execute and deliver a Transfer Application (a) the right to negotiate such Certificate to a purchaser or other transferee and (b) the right to transfer the right to request admission as a Substituted Limited Partner to such purchaser or other transferee in respect of the transferred Limited Partner Interests. Each

transferee of a Limited Partner Interest (including any nominee holder or an agent acquiring such Limited Partner Interest for the account of another Person) who executes and delivers a Transfer Application shall, by virtue of such execution and delivery, be an Assignee and be deemed to have applied to become a Substituted Limited Partner with respect to the Limited Partner Interests so transferred to such Person. Such Assignee shall become a Substituted Limited Partner (x) at such time as the General Partner consents thereto, which consent may be given or withheld in the General Partner’s discretion, and (y) when any such admission is shown on the books and records of the Partnership. If such consent is withheld, such transferee shall be an Assignee. An Assignee shall have an interest in the Partnership equivalent to that of a Limited Partner with respect to allocations and distributions, including liquidating distributions, of the Partnership. With respect to voting rights attributable to Limited Partner Interests that are held by Assignees, the General Partner shall be deemed to be the Limited Partner with respect thereto and shall, in exercising the voting rights in respect of such Limited Partner Interests on any matter, vote such Limited Partner Interests at the written direction of the Assignee who is the Record Holder of such Limited Partner Interests. If no such written direction is received, such Limited Partner Interests will not be voted. An Assignee shall have no other rights of a Limited Partner.

Section 10.3 Admission of Successor General Partner.

A successor General Partner approved pursuant to Section 11.1 or 11.2 or the transferee of or successor to all of the General Partner Interest pursuant to Section 4.6 who is proposed to be admitted as a successor General Partner shall be admitted to the Partnership as the General Partner, effective immediately prior to the withdrawal or removal of the predecessor or transferring General Partner, pursuant to Section 11.1 or 11.2 or the transfer of the General Partner Interest pursuant to Section 4.6, provided, however, that no such successor shall be admitted to the Partnership until compliance with the terms of Section 4.6 has occurred and such successor has executed and delivered such other documents or instruments as may be required to effect such admission. Any such successor shall, subject to the terms hereof, carry on the business of the members of the Partnership Group without dissolution.

Section 10.4 Admission of Additional Limited Partners.

(a) A Person (other than the General Partner, an Initial Limited Partner or a Substituted Limited Partner) who makes a Capital Contribution to the Partnership in accordance with this Agreement shall be admitted to the Partnership as an Additional Limited Partner only upon furnishing to the General Partner

(i) evidence of acceptance in form satisfactory to the General Partner of all of the terms and conditions of this Agreement, including the power of attorney granted in Section 2.6, and

(ii) such other documents or instruments as may be required in the discretion of the General Partner to effect such Person’s admission as an Additional Limited Partner.

(b) Notwithstanding anything to the contrary in this Section 10.4, no Person shall be admitted as an Additional Limited Partner without the consent of the General Partner, which consent may be given or withheld in the General Partner’s discretion. The admission of any Person as an Additional Limited Partner shall become effective on the date upon which the name of such Person is recorded as such in the books and records of the Partnership, following the consent of the General Partner to such admission.

Section 10.5 Amendment of Agreement and Certificate of Limited Partnership.

To effect the admission to the Partnership of any Partner, the General Partner shall take all steps necessary and appropriate under the Delaware Act to amend the records of the Partnership to reflect such admission and, if necessary, to prepare as soon as practicable an amendment to this Agreement and, if required by law, the General Partner shall prepare and file an amendment to the Certificate of Limited Partnership, and the General Partner may for this purpose, among others, exercise the power of attorney granted pursuant to Section 2.6.

ARTICLE XI

WITHDRAWAL OR REMOVAL OF PARTNERS

Section 11.1 Withdrawal of the General Partner.

(a) The General Partner shall be deemed to have withdrawn from the Partnership upon the occurrence of any one of the following events (each such event herein referred to as an “Event of Withdrawal”);

(i) The General Partner voluntarily withdraws from the Partnership by giving written notice to the other Partners;

(ii) The General Partner transfers all of its rights as General Partner pursuant to Section 4.6;

(iii) The General Partner is removed pursuant to Section 11.2;

(iv) The General Partner (A) makes a general assignment for the benefit of creditors; (B) files a voluntary bankruptcy petition for relief under Chapter 7 of the United States Bankruptcy Code; (C) files a petition or answer seeking for itself a liquidation, dissolution or similar relief (but not a reorganization) under any law; (D) files an answer or other pleading admitting or failing to contest the material allegations of a petition filed against the General Partner in a proceeding of the type described in clauses (A)-(C) of this Section 11.1(a)(iv); or (E) seeks, consents to or acquiesces in the appointment of a trustee (but not a debtor-in-possession), receiver or liquidator of the General Partner or of all or any substantial part of its properties;

(v) A final and non-appealable order of relief under Chapter 7 of the United States Bankruptcy Code is entered by a court with appropriate jurisdiction pursuant to a voluntary or involuntary petition by or against the General Partner; or

(vi) (A) in the event the General Partner is a corporation, a certificate of dissolution or its equivalent is filed for the General Partner, or 90 days expire after the date of notice to the General Partner of revocation of its charter without a reinstatement of its charter, under the laws of its state of incorporation; (B) in the event the General Partner is a partnership or a limited liability company, the dissolution and commencement of winding up of the General Partner; (C) in the event the General Partner is acting in such capacity by virtue of being a trustee of a trust, the termination of the trust; (D) in the event the General Partner is a natural person, his death or adjudication of incompetency; and (E) otherwise in the event of the termination of the General Partner.

If an Event of Withdrawal specified in Section 11.1(a)(iv), (v) or (vi)(A), (B), (C) or (E) occurs, the withdrawing General Partner shall give notice to the Limited Partners within 30 days after such occurrence. The Partners hereby agree that only the Events of Withdrawal described in this Section 11.1 shall result in the withdrawal of the General Partner from the Partnership.

(b) Withdrawal of the General Partner from the Partnership upon the occurrence of an Event of Withdrawal shall not constitute a breach of this Agreement under the following circumstances: (i) at any time during the period beginning on the Closing Date and ending at 12:00 midnight, Eastern Standard Time, on June 30, 2012, the General Partner voluntarily withdraws by giving at least 90 days’ advance notice of its intention to withdraw to the Limited Partners; provided that prior to the effective date of such withdrawal, the withdrawal is approved by Unitholders holding at least a majority of the Outstanding Common Units (excluding Common Units held by the General Partner and its Affiliates) and the General Partner delivers to the Partnership an Opinion of Counsel (“Withdrawal Opinion of Counsel”) that such withdrawal (following the selection of the successor General Partner) would not result in the loss of the limited liability of any Limited Partner or any Group Member or cause any Group Member to be treated as an association taxable as a corporation or otherwise to be taxed as an entity for federal income tax purposes (to the extent not previously treated as such); (ii) at any time after 12:00 midnight, Eastern Standard Time, on June 30, 2012, the General Partner voluntarily withdraws by giving at least 90 days’ advance notice to the Unitholders, such withdrawal to take effect on the date specified in such notice; (iii) at any time that the General Partner ceases to be the General Partner pursuant to Section 11.1(a)(ii) or is removed pursuant to Section 11.2; or (iv) notwithstanding clause (i) of this sentence, at any time that the General Partner voluntarily withdraws by giving at least 90 days’ advance notice of its intention to withdraw to the Limited Partners, such withdrawal to take effect on the date specified in the notice, if at the time such notice is given one Person and its Affiliates (other than the General Partner and its Affiliates) own beneficially or of record or control at least 50% of the Outstanding Units. The withdrawal of the General Partner from the Partnership upon the occurrence of an Event of Withdrawal shall also constitute the withdrawal of the General Partner as general partner or managing member, to the extent applicable, of the other Group Members. If the General Partner gives a notice of

withdrawal pursuant to Section 11.1(a)(i), the holders of a Unit Majority, may, prior to the effective date of such withdrawal, elect a successor General Partner. The Person so elected as successor General Partner shall automatically become the successor general partner or managing member, to the extent applicable, of the other Group Members of which the General Partner is a general partner of a managing member. If, prior to the effective date of the General Partner’s withdrawal, a successor is not selected by the Unitholders as provided herein or the Partnership does not receive a Withdrawal Opinion of Counsel, the Partnership shall be dissolved in accordance with Section 12.1. Any successor General Partner elected in accordance with the terms of this Section 11.1 shall be subject to the provisions of Section 10.3.

Section 11.2 Removal of the General Partner.

The General Partner may be removed if such removal is approved by the Unitholders holding at least 66 2/3% of the Outstanding Units (including Units held by the General Partner and its Affiliates). Any such action by such holders for removal of the General Partner must also provide for the election of a successor General Partner by the Unitholders holding a majority of the outstanding Common Units voting as a class and a majority of the outstanding Subordinated Units voting as a class (including Units held by the General Partner and its Affiliates). Such removal shall be effective immediately following the admission of a successor General Partner pursuant to Section 10.3. The removal of the General Partner shall also automatically constitute the removal of the General Partner as general partner or managing member, to the extent applicable, of the other Group Members of which the General Partner is a general partner or a managing member. If a Person is elected as a successor General Partner in accordance with the terms of this Section 11.2, such Person shall, upon admission pursuant to Section 10.3, automatically become a successor general partner or managing member, to the extent applicable, of the other Group Members of which the General Partner is a general partner or a managing member. The right of the holders of Outstanding Units to remove the General Partner shall not exist or be exercised unless the Partnership has received an opinion opining as to the matters covered by a Withdrawal Opinion of Counsel. Any successor General Partner elected in accordance with the terms of this Section 11.2 shall be subject to the provisions of Section 10.3.

Section 11.3 Interest of Departing Partner and Successor General Partner.

(a) In the event of (i) withdrawal of the General Partner under circumstances where such withdrawal does not violate this Agreement or (ii) removal of the General Partner by the holders of Outstanding Units under circumstances where Cause does not exist, if the successor General Partner is elected in accordance with the terms of Section 11.1 or 11.2, the Departing Partner shall have the option, exercisable prior to the effective date of the departure of such Departing Partner, to require its successor to purchase its General Partner Interest and its general partner interest (or equivalent interest), if any, in the other Group Members and all of its Incentive Distribution Rights (collectively, the “Combined Interest”) in exchange for an amount in cash equal to the fair market value of such Combined Interest, such amount to be determined and payable as of the effective date of its departure. If the General Partner is removed by the Unitholders under circumstances where Cause exists or if the General Partner withdraws under circumstances where such withdrawal violates this Agreement, and if a successor General

Partner is elected in accordance with the terms of Section 11.1 or 11.2, such successor shall have the option, exercisable prior to the effective date of the departure of such Departing Partner, to purchase the Combined Interest for such fair market value of such Combined Interest of the Departing Partner. In either event, the Departing Partner shall be entitled to receive all reimbursements due such Departing Partner pursuant to Section 7.4, including any employee-related liabilities (including severance liabilities), incurred in connection with the termination of any employees employed by the Departing Partner for the benefit of the Partnership or the other Group Members.

For purposes of this Section 11.3(a), the fair market value of the Departing Partner’s Combined Interest shall be determined by agreement between the Departing Partner and its successor or, failing agreement within 30 days after the effective date of such Departing Partner’s departure, by an independent investment banking firm or other independent expert selected by the Departing Partner and its successor, which, in turn, may rely on other experts, and the determination of which shall be conclusive as to such matter. If such parties cannot agree upon one independent investment banking firm or other independent expert within 45 days after the effective date of such departure, then the Departing Partner shall designate an independent investment banking firm or other independent expert, the Departing Partner’s successor shall designate an independent investment banking firm or other independent expert, and such firms or experts shall mutually select a third independent investment banking firm or independent expert, which third independent investment banking firm or other independent expert shall determine the fair market value of the Combined Interest of the Departing Partner. In making its determination, such third independent investment banking firm or other independent expert may consider the then current trading price of Units on any National Securities Exchange on which Units are then listed, the value of the Partnership’s assets, the rights and obligations of the Departing Partner and other factors it may deem relevant.

(b) If the Combined Interest is not purchased in the manner set forth in Section 11.3(a), the Departing Partner (or its transferee) shall become a Limited Partner and its Combined Interest shall be converted into Common Units pursuant to a valuation made by an investment banking firm or other independent expert selected pursuant to Section 11.3(a), without reduction in such Partnership Interest (but subject to proportionate dilution by reason of the admission of its successor). Any successor General Partner shall indemnify the Departing Partner (or its transferee) as to all debts and liabilities of the Partnership arising on or after the date on which the Departing Partner (or its transferee) becomes a Limited Partner. For purposes of this Agreement, conversion of the Combined Interest of the Departing Partner to Common Units will be characterized as if the Departing Partner (or its transferee) contributed its Combined Interest to the Partnership in exchange for the newly issued Common Units.

(c) If a successor General Partner is elected in accordance with the terms of Section 11.1 or 11.2 and the option described in Section 11.3(a) is not exercised by the party entitled to do so, the successor General Partner shall, at the effective date of its admission to the Partnership, contribute to the Partnership cash in the amount equal to 2/98ths of the Net Agreed Value of the Partnership’s assets on such date. In such event, such successor General Partner shall, subject to the following sentence, be entitled to 2% of all Partnership allocations and

distributions to which the Departing Partner was entitled. In addition, the successor General Partner shall cause this Agreement to be amended to reflect that, from and after the date of such successor General Partner’s admission, the successor General Partner’s interest in all Partnership distributions and allocations shall be 2%.

Section 11.4 Termination of Subordination Period, Conversion of Subordinated Units and Extinguishment of Cumulative Common Unit Arrearages.

Notwithstanding any provision of this Agreement, if the General Partner is removed as general partner of the Partnership under circumstances where Cause does not exist and Units held by the General Partner and its Affiliates are not voted in favor of such removal, (i) the Subordination Period will end and all Outstanding Subordinated Units will immediately and automatically convert into Common Units on a one-for-one basis and (ii) all Cumulative Common Unit Arrearages on the Common Units will be extinguished.

Section 11.5 Withdrawal of Limited Partners.

No Limited Partner shall have any right to withdraw from the Partnership; provided, however, that when a transferee of a Limited Partner’s Limited Partner Interest becomes a Record Holder of the Limited Partner Interest so transferred, such transferring Limited Partner shall cease to be a Limited Partner with respect to the Limited Partner Interest so transferred.

ARTICLE XII

DISSOLUTION AND LIQUIDATION

Section 12.1 Dissolution.

The Partnership shall not be dissolved by the admission of Substituted Limited Partners or Additional Limited Partners or by the admission of a successor General Partner in accordance with the terms of this Agreement. Upon the removal or withdrawal of the General Partner, if a successor General Partner is elected pursuant to Section 11.1 or 11.2, the Partnership shall not be dissolved and such successor General Partner shall continue the business of the Partnership. The Partnership shall dissolve, and (subject to Section 12.2) its affairs shall be wound up, upon:

(a) an Event of Withdrawal of the General Partner as provided in Section 11.1(a) (other than Section 11.1(a)(ii)), unless a successor is elected and an Opinion of Counsel is received as provided in Section 11.1(b) or 11.2 and such successor is admitted to the Partnership pursuant to Section 10.3;

(b) an election to dissolve the Partnership by the General Partner that is approved by the holders of a Unit Majority;

(c) the entry of a decree of judicial dissolution of the Partnership pursuant to the provisions of the Delaware Act; or

(d) the sale of all or substantially all of the assets and properties of the Partnership Group.

Section 12.2 Continuation of the Business of the Partnership After Dissolution.

Upon (a) dissolution of the Partnership following an Event of Withdrawal caused by the withdrawal or removal of the General Partner as provided in Section 11.1(a)(i) or (iii) and the failure of the Partners to select a successor to such Departing Partner pursuant to Section 11.1 or 11.2, then within 90 days thereafter, or (b) dissolution of the Partnership upon an event constituting an Event of Withdrawal as defined in Section 11.1(a)(iv), (v) or (vi), then, to the maximum extent permitted by law, within 180 days thereafter, the holders of a Unit Majority may elect to reconstitute the Partnership and continue its business on the same terms and conditions set forth in this Agreement by forming a new limited partnership on terms identical to those set forth in this Agreement and having as the successor General partner a Person approved by the holders of a Unit Majority. Unless such an election is made within the applicable time period as set forth above, the Partnership shall conduct only activities necessary to wind up its affairs. If such an election is so made, then:

(i) the reconstituted Partnership shall continue unless earlier dissolved in accordance with this Article XII;

(ii) if the successor General Partner is not the former General Partner, then the interest of the former General Partner shall be treated in the manner provided in Section 11.3; and

(iii) all necessary steps shall be taken to cancel this Agreement and the Certificate of Limited Partnership and to enter into and, as necessary, to file a new partnership agreement and certificate of limited partnership, and the successor General Partner may for this purpose exercise the powers of attorney granted the General Partner pursuant to Section 2.6; provided, that the right of the holders of a Unit Majority to approve a successor General Partner and to reconstitute and to continue the business of the Partnership shall not exist and may not be exercised unless the Partnership has received an Opinion of Counsel that (x) the exercise of the right would not result in the loss of limited liability of any Limited Partner and (y) neither the Partnership, the reconstituted limited partnership nor the Operating Company or any other Group Member would be treated as an association taxable as a corporation or otherwise be taxable as an entity for federal income tax purposes upon the exercise of such right to continue.

Section 12.3 Liquidator.

Upon dissolution of the Partnership, unless the Partnership is continued under an election to reconstitute and continue the Partnership pursuant to Section 12.2, the General Partner shall select one or more Persons to act as Liquidator. The Liquidator (if other than the General Partner) shall be entitled to receive such compensation for its services as may be approved by holders of at least a majority of the Outstanding Common Units and Subordinated Units voting

as a single class. The Liquidator (if other than the General Partner) shall agree not to resign at any time without 15 days’ prior notice and may be removed at any time, with or without cause, by notice of removal approved by holders of at least a majority of the Outstanding Common Units and Subordinated Units voting as a single class. Upon dissolution, removal or resignation of the Liquidator, a successor and substitute Liquidator (who shall have and succeed to all rights, powers and duties of the original Liquidator) shall within 30 days thereafter be approved by holders of at least a majority of the Outstanding Common Units and Subordinated Units voting as a single class. The right to approve a successor or substitute Liquidator in the manner provided herein shall be deemed to refer also to any such successor or substitute Liquidator approved in the manner herein provided. Except as expressly provided in this Article XII, the Liquidator approved in the manner provided herein shall have and may exercise, without further authorization or consent of any of the parties hereto, all of the powers conferred upon the General Partner under the terms of this Agreement (but subject to all of the applicable limitations, contractual and otherwise, upon the exercise of such powers, other than the limitation on sale set forth in Section 7.3(b)) to the extent necessary or desirable in the good faith judgment of the Liquidator to carry out the duties and functions of the Liquidator hereunder for and during such period of time as shall be reasonably required in the good faith judgment of the Liquidator to complete the winding up and liquidation of the Partnership as provided for herein.

Section 12.4 Liquidation.

The Liquidator shall proceed to dispose of the assets of the Partnership, discharge its liabilities, and otherwise wind up its affairs in such manner and over such period as the Liquidator determines to be in the best interest of the Partners, subject to Section 17-804 of the Delaware Act and the following:

(a) The assets may be disposed of by public or private sale or by distribution in kind to one or more Partners on such terms as the Liquidator and such Partner or Partners may agree. If any property is distributed in kind, the Partner receiving the property shall be deemed for purposes of Section 12.4(c) to have received cash equal to its fair market value; and contemporaneously therewith, appropriate cash distributions must be made to the other Partners. The Liquidator may, in its absolute discretion, defer liquidation or distribution of the Partnership’s assets for a reasonable time if it determines that an immediate sale or distribution of all or some of the Partnership’s assets would be impractical or would cause undue loss to the Partners. The Liquidator may, in its absolute discretion, distribute the Partnership’s assets, in whole or in part, in kind if it determines that a sale would be impractical or would cause undue loss to the Partners.

(b) Liabilities of the Partnership include amounts owed to the Liquidator as compensation for serving in such capacity (subject to the terms of Section 12.3) and amounts to Partners otherwise than in respect of their distribution rights under Article VI. With respect to any liability that is contingent, conditional or unmatured or is otherwise not yet due and payable, the Liquidator shall either settle such claim for such amount as it thinks appropriate or establish a reserve of cash or other assets to provide for its payment. When paid, any unused portion of the reserve shall be distributed as additional liquidation proceeds.

(c) All property and all cash in excess of that required to discharge liabilities as provided in Section 12.4(b) shall be distributed to the Partners in accordance with, and to the extent of, the positive balances in their respective Capital Accounts, as determined after taking into account all Capital Account adjustments (other than those made by reason of distributions pursuant to this Section 12.4(c)) for the taxable year of the Partnership during which the liquidation of the Partnership occurs (with such date of occurrence being determined pursuant to Treasury Regulation Section 1.704-1(b)(2)(ii)(g)), and such distribution shall be made by the end of such taxable year (or, if later, within 90 days after said date of such occurrence).

Section 12.5 Cancellation of Certificate of Limited Partnership.

Upon the completion of the distribution of Partnership cash and property as provided in Section 12.4 in connection with the liquidation of the Partnership, the Partnership shall be terminated and the Certificate of Limited Partnership and all qualifications of the Partnership as a foreign limited partnership in jurisdictions other than the State of Delaware shall be canceled and such other actions as may be necessary to terminate the Partnership shall be taken.

Section 12.6 Return of Contributions.

The General Partner shall not be personally liable for, and shall have no obligation to contribute or loan any monies or property to the Partnership to enable it to effectuate, the return of the Capital Contributions of the Limited Partners or Unitholders, or any portion thereof, it being expressly understood that any such return shall be made solely from Partnership assets.

Section 12.7 Waiver of Partition.

To the maximum extent permitted by law, each Partner hereby waives any right to partition of the Partnership property.

Section 12.8 Capital Account Restoration.

No Limited Partner shall have any obligation to restore any negative balance in its Capital Account upon liquidation of the Partnership. The General Partner shall be obligated to restore any negative balance in its Capital Account upon liquidation of its interest in the Partnership by the end of the taxable year of the Partnership during which such liquidation occurs, or, if later, within 90 days after the date of such liquidation.

ARTICLE XIII

AMENDMENT OF PARTNERSHIP AGREEMENT; MEETINGS; RECORD DATE

Section 13.1 Amendment to be Adopted Solely by the General Partner.

Each Partner agrees that the General Partner, without the approval of any Partner or Assignee, may amend any provision of this Agreement and execute, swear to, acknowledge, deliver, file and record whatever documents may be required in connection therewith, to reflect:

(a) a change in the name of the Partnership, the location of the principal place of business of the Partnership, the registered agent of the Partnership or the registered office of the Partnership;

(b) admission, substitution, withdrawal or removal of Partners in accordance with this Agreement;

(c) a change that, in the sole discretion of the General Partner, is necessary or advisable to qualify or continue the qualification of the Partnership as a limited partnership or a partnership in which the Limited Partners have limited liability under the laws of any state or to ensure that the Group Members will not be treated as associations taxable as corporations or otherwise taxed as entities for federal income tax purposes;

(d) a change that, in the discretion of the General Partner, (i) does not adversely affect the Limited Partners (including any particular class of Partnership Interests as compared to other classes of Partnership Interests) in any material respect, (ii) is necessary or advisable to (A) satisfy any requirements, conditions or guidelines contained in any opinion, directive, order, ruling or regulation of any federal or state agency or judicial authority or contained in any federal or state statute (including the Delaware Act) or (B) facilitate the trading of the Units (including the division of any class or classes of Outstanding Units into different classes to facilitate uniformity of tax consequences within such classes of Units) or comply with any rule, regulation, guideline or requirement of any National Securities Exchange on which the Units are or will be listed for trading, compliance with any of which the General Partner determines in its discretion to be in the best interests of the Partnership and the Limited Partners, (iii) is necessary or advisable in connection with action taken by the General Partner pursuant to Section 5.10 or (iv) is required to effect the intent expressed in the Registration Statement or the intent of the provisions of this Agreement or is otherwise contemplated by this Agreement;

(e) a change in the fiscal year or taxable year of the Partnership and any changes that, in the discretion of the General Partner, are necessary or advisable as a result of a change in the fiscal year or taxable year of the Partnership including, if the General Partner shall so determine, a change in the definition of “Quarter” and the dates on which distributions are to be made by the Partnership;

(f) an amendment that is necessary, in the Opinion of Counsel, to prevent the Partnership, or the General Partner or its directors, officers, trustees or agents from in any manner being subjected to the provisions of the Investment Company Act of 1940, as amended, the Investment Advisers Act of 1940, as amended, or “plan asset” regulations adopted under the Employee Retirement Income Security Act of 1974, as amended, regardless of whether such are substantially similar to plan asset regulations currently applied or proposed by the United States Department of Labor;

(g) subject to the terms of Section 5.7, an amendment that, in the discretion of the General Partner, is necessary or advisable in connection with the authorization of issuance of any class or series of Partnership Securities pursuant to Section 5.6;

(h) any amendment expressly permitted in this Agreement to be made by the General Partner acting alone;

(i) an amendment effected, necessitated or contemplated by a Merger Agreement approved in accordance with Section 14.3;

(j) an amendment that, in the discretion of the General Partner, is necessary or advisable to reflect, account for and deal with appropriately the formation by the Partnership of, or investment by the Partnership in, any corporation, partnership, joint venture, limited liability company or other entity, in connection with the conduct by the Partnership of activities permitted by the terms of Section 2.4;

(k) a merger or conveyance pursuant to Section 14.3(d); or

(l) any other amendments substantially similar to the foregoing.

Section 13.2 Amendment Procedures.

Except as provided in Sections 13.1 and 13.3, all amendments to this Agreement shall be made in accordance with the following requirements. Amendments to this Agreement may be proposed only by or with the consent of the General Partner which consent may be given or withheld in its sole discretion. A proposed amendment shall be effective upon its approval by the holders of a Unit Majority, unless a greater or different percentage is required under this Agreement or by Delaware law. Each proposed amendment that requires the approval of the holders of a specified percentage of Outstanding Units shall be set forth in a writing that contains the text of the proposed amendment. If such an amendment is proposed, the General Partner shall seek the written approval of the requisite percentage of Outstanding Units or call a meeting of the Unitholders to consider and vote on such proposed amendment. The General Partner shall notify all Record Holders upon final adoption of any such proposed amendments.

Section 13.3 Amendment Requirements.

(a) Notwithstanding the provisions of Sections 13.1 and 13.2, no provision of this Agreement that establishes a percentage of Outstanding Units (including Units deemed owned by the General Partner) required to take any action shall be amended, altered, changed, repealed or rescinded in any respect that would have the effect of reducing such voting percentage unless such amendment is approved by the written consent or the affirmative vote of holders of Outstanding Units whose aggregate Outstanding Units constitute not less than the voting requirement sought to be reduced.

(b) Notwithstanding the provisions of Sections 13.1 and 13.2, no amendment to this Agreement may (i) enlarge the obligations of any Limited Partner without its consent, unless such shall be deemed to have occurred as a result of an amendment approved pursuant to Section 13.3(c), (ii) enlarge the obligations of, restrict in any way any action by or rights of, or reduce in any way the amounts distributable, reimbursable or otherwise payable to, the General Partner or

any of its Affiliates without its consent, which consent may be given or withheld in its sole discretion, (iii) change Section 12.1(b), or (iv) change the term of the Partnership or, except as set forth in Section 12.1(b), give any Person the right to dissolve the Partnership.

(c) Except as provided in Section 14.3, and without limitation of the General Partner’s authority to adopt amendments to this Agreement without the approval of any Partners or Assignees as contemplated in Section 13.1, any amendment that would have a material adverse effect on the rights or preferences of any class of Partnership Interests in relation to other classes of Partnership Interests must be approved by the holders of not less than a majority of the Outstanding Partnership Interests of the class affected.

(d) Notwithstanding any other provision of this Agreement, except for amendments pursuant to Section 13.1 and except as otherwise provided by Section 14.3(b), no amendments shall become effective without the approval of the holders of at least 90% of the Outstanding Units voting as a single class unless the Partnership obtains an Opinion of Counsel to the effect that such amendment will not affect the limited liability of any Limited Partner under applicable law.

(e) Except as provided in Section 13.1, this Section 13.3 shall only be amended with the approval of the holders of at least 90% of the Outstanding Units.

Section 13.4 Special Meetings.

All acts of Limited Partners to be taken pursuant to this Agreement shall be taken in the manner provided in this Article XIII. Special meetings of the Limited Partners may be called by the General Partner or by Limited Partners owning 20% or more of the Outstanding Units of the class or classes for which a meeting is proposed. Limited Partners shall call a special meeting by delivering to the General Partner one or more requests in writing stating that the signing Limited Partners wish to call a special meeting and indicating the general or specific purposes for which the special meeting is to be called. Within 60 days after receipt of such a call from Limited Partners or within such greater time as may be reasonably necessary for the Partnership to comply with any statutes, rules, regulations, listing agreements or similar requirements governing the holding of a meeting or the solicitation of proxies for use at such a meeting, the General Partner shall send a notice of the meeting to the Limited Partners either directly or indirectly through the Transfer Agent. A meeting shall be held at a time and place determined by the General Partner on a date not less than 10 days nor more than 60 days after the mailing of notice of the meeting. Limited Partners shall not vote on matters that would cause the Limited Partners to be deemed to be taking part in the management and control of the business and affairs of the Partnership so as to jeopardize the Limited Partners’ limited liability under the Delaware Act or the law of any other state in which the Partnership is qualified to do business.

Section 13.5 Notice of a Meeting.

Notice of a meeting called pursuant to Section 13.4 shall be given to the Record Holders of the class or classes of Units for which a meeting is proposed in writing by mail or other means

of written communication in accordance with Section 16.1. The notice shall be deemed to have been given at the time when deposited in the mail or sent by other means of written communication.

Section 13.6 Record Date.

For purposes of determining the Limited Partners entitled to notice of or to vote at a meeting of the Limited Partners or to give approvals without a meeting as provided in Section 13.11 the General Partner may set a Record Date, which shall not be less than 10 nor more than 60 days before (a) the date of the meeting (unless such requirement conflicts with any rule, regulation, guideline or requirement of any National Securities Exchange on which the Units are listed for trading, in which case the rule, regulation, guideline or requirement of such exchange shall govern) or (b) in the event that approvals are sought without a meeting, the date by which Limited Partners are requested in writing by the General Partner to give such approvals.

Section 13.7 Adjournment.

When a meeting is adjourned to another time or place, notice need not be given of the adjourned meeting and a new Record Date need not be fixed, if the time and place thereof are announced at the meeting at which the adjournment is taken, unless such adjournment shall be for more than 45 days. At the adjourned meeting, the Partnership may transact any business which might have been transacted at the original meeting. If the adjournment is for more than 45 days or if a new Record Date is fixed for the adjourned meeting, a notice of the adjourned meeting shall be given in accordance with this Article XIII.

Section 13.8 Waiver of Notice; Approval of Meeting; Approval of Minutes.

The transactions of any meeting of Limited Partners, however called and noticed, and whenever held, shall be as valid as if it had occurred at a meeting duly held after regular call and notice, if a quorum is present either in person or by proxy, and if, either before or after the meeting, Limited Partners representing such quorum who were present in person or by proxy and entitled to vote, sign a written waiver of notice or an approval of the holding of the meeting or an approval of the minutes thereof. All waivers and approvals shall be filed with the Partnership records or made a part of the minutes of the meeting. Attendance of a Limited Partner at a meeting shall constitute a waiver of notice of the meeting, except when the Limited Partner does not approve, at the beginning of the meeting, of the transaction of any business because the meeting is not lawfully called or convened; and except that attendance at a meeting is not a waiver of any right to disapprove the consideration of matters required to be included in the notice of the meeting, but not so included, if the disapproval is expressly made at the meeting.

Section 13.9 Quorum.

The holders of a majority of the Outstanding Units of the class or classes for which a meeting has been called (including Outstanding Units deemed owned by the General Partner) represented in person or by proxy shall constitute a quorum at a meeting of Limited Partners of

such class or classes unless any such action by the Limited Partners requires approval by holders of a greater percentage of such Units, in which case the quorum shall be such greater percentage. At any meeting of the Limited Partners duly called and held in accordance with this Agreement at which a quorum is present, the act of Limited Partners holding Outstanding Units that in the aggregate represent a majority of the Outstanding Units entitled to vote and be present in person or by proxy at such meeting shall be deemed to constitute the act of all Limited Partners, unless a greater or different percentage is required with respect to such action under the provisions of this Agreement, in which case the act of the Limited Partners holding Outstanding Units that in the aggregate represent at least such greater or different percentage shall be required. The Limited Partners present at a duly called or held meeting at which a quorum is present may continue to transact business until adjournment, notwithstanding the withdrawal of enough Limited Partners to leave less than a quorum, if any action taken (other than adjournment) is approved by the required percentage of Outstanding Units specified in this Agreement (including Outstanding Units deemed owned by the General Partner). In the absence of a quorum any meeting of Limited Partners may be adjourned from time to time by the affirmative vote of holders of at least a majority of the Outstanding Units entitled to vote at such meeting (including Outstanding Units deemed owned by the General Partner) represented either in person or by proxy, but no other business may be transacted, except as provided in Section 13.7.

Section 13.10 Conduct of a Meeting.

The General Partner shall have full power and authority concerning the manner of conducting any meeting of the Limited Partners or solicitation of approvals in writing, including the determination of Persons entitled to vote, the existence of a quorum, the satisfaction of the requirements of Section 13.4, the conduct of voting, the validity and effect of any proxies and the determination of any controversies, votes or challenges arising in connection with or during the meeting or voting. The General Partner shall designate a Person to serve as chairman of any meeting and shall further designate a Person to take the minutes of any meeting. All minutes shall be kept with the records of the Partnership maintained by the General Partner. The General Partner may make such other regulations consistent with applicable law and this Agreement as it may deem advisable concerning the conduct of any meeting of the Limited Partners or solicitation of approvals in writing, including regulations in regard to the appointment of proxies, the appointment and duties of inspectors of votes and approvals, the submission and examination of proxies and other evidence of the right to vote, and the revocation of approvals in writing.

Section 13.11 Action Without a Meeting.

If authorized by the General Partner, any action that may be taken at a meeting of the Limited Partners may be taken without a meeting if an approval in writing setting forth the action so taken is signed by Limited Partners owning not less than the minimum percentage of the Outstanding Units (including Units deemed owned by the General Partner) that would be necessary to authorize or take such action at a meeting at which all the Limited Partners were present and voted (unless such provision conflicts with any rule, regulation, guideline or requirement of any National Securities Exchange on which the Units are listed for trading, in which case the rule, regulation, guideline or requirement of such exchange shall govern). Prompt

notice of the taking of action without a meeting shall be given to the Limited Partners who have not approved in writing. The General Partner may specify that any written ballot submitted to Limited Partners for the purpose of taking any action without a meeting shall be returned to the Partnership within the time period, which shall be not less than 20 days, specified by the General Partner. If a ballot returned to the Partnership does not vote all of the Units held by the Limited Partners, the Partnership shall be deemed to have failed to receive a ballot for the Units that were not voted. If approval of the taking of any action by the Limited Partners is solicited by any Person other than by or on behalf of the General Partner, the written approvals shall have no force and effect unless and until (a) they are deposited with the Partnership in care of the General Partner, (b) approvals sufficient to take the action proposed are dated as of a date not more than 90 days prior to the date sufficient approvals are deposited with the Partnership and (c) an Opinion of Counsel is delivered to the General Partner to the effect that the exercise of such right and the action proposed to be taken with respect to any particular matter (i) will not cause the Limited Partners to be deemed to be taking part in the management and control of the business and affairs of the Partnership so as to jeopardize the Limited Partners’ limited liability, and (ii) is otherwise permissible under the state statutes then governing the rights, duties and liabilities of the Partnership and the Partners.

Section 13.12 Voting and Other Rights.

(a) Only those Record Holders of the Units on the Record Date set pursuant to Section 13.6 (and also subject to the limitations contained in the definition of “Outstanding”) shall be entitled to notice of, and to vote at, a meeting of Limited Partners or to act with respect to matters as to which the holders of the Outstanding Units have the right to vote or to act. All references in this Agreement to votes of, or other acts that may be taken by, the Outstanding Units shall be deemed to be references to the votes or acts of the Record Holders of such Outstanding Units.

(b) With respect to Units that are held for a Person’s account by another Person (such as a broker, dealer, bank, trust company or clearing corporation, or an agent of any of the foregoing), in whose name such Units are registered, such other Person shall, in exercising the voting rights in respect of such Units on any matter, and unless the arrangement between such Persons provides otherwise, vote such Units in favor of, and at the direction of, the Person who is the beneficial owner, and the Partnership shall be entitled to assume it is so acting without further inquiry. The provisions of this Section 13.12(b) (as well as all other provisions of this Agreement) are subject to the provisions of Section 4.3.

ARTICLE XIV

MERGER

Section 14.1 Authority.

The Partnership may merge or consolidate with one or more corporations, limited liability companies, business trusts or associations, real estate investment trusts, common law

trusts or unincorporated businesses, including a general partnership or limited partnership, formed under the laws of the State of Delaware or any other state of the United States of America, pursuant to a written agreement of merger or consolidation (“Merger Agreement”) in accordance with this Article XIV.

Section 14.2 Procedure for Merger or Consolidation.

Merger or consolidation of the Partnership pursuant to this Article XIV requires the prior approval of the General Partner. If the General Partner shall determine, in the exercise of its discretion, to consent to the merger or consolidation, the General Partner shall approve the Merger Agreement, which shall set forth:

(a) the names and jurisdictions of formation or organization of each of the business entities proposing to merge or consolidate;

(b) the name and jurisdiction of formation or organization of the business entity that is to survive the proposed merger or consolidation (the “Surviving Business Entity”);

(c) the terms and conditions of the proposed merger or consolidation;

(d) the manner and basis of exchanging or converting the equity securities of each constituent business entity for, or into, cash, property or general or limited partner interests, rights, securities or obligations of the Surviving Business Entity; and (i) if any general or limited partner interests, securities or rights of any constituent business entity are not to be exchanged or converted solely for, or into, cash, property or general or limited partner interests, rights, securities or obligations of the Surviving Business Entity, the cash, property or general or limited partner interests, rights, securities or obligations of any limited partnership, corporation, trust or other entity (other than the Surviving Business Entity) which the holders of such general or limited partner interests, securities or rights are to receive in exchange for, or upon conversion of their general or limited partner interests, securities or rights, and (ii) in the case of securities represented by certificates, upon the surrender of such certificates, which cash, property or general or limited partner interests, rights, securities or obligations of the Surviving Business Entity or any general or limited partnership, corporation, trust or other entity (other than the Surviving Business Entity), or evidences thereof, are to be delivered;

(e) a statement of any changes in the constituent documents or the adoption of new constituent documents (the articles or certificate of incorporation, articles of trust, declaration of trust, certificate or agreement of limited partnership or other similar charter or governing document) of the Surviving Business Entity to be effected by such merger or consolidation;

(f) the effective time of the merger, which may be the date of the filing of the certificate of merger pursuant to Section 14.4 or a later date specified in or determinable in accordance with the Merger Agreement (provided, that if the effective time of the merger is to be later than the date of the filing of the certificate of merger, the effective time shall be fixed no later than the time of the filing of the certificate of merger and stated therein); and

(g) such other provisions with respect to the proposed merger or consolidation as are deemed necessary or appropriate by the General Partner.

Section 14.3 Approval by Limited Partners of Merger or Consolidation.

(a) Except as provided in Section 14.3(d), the General Partner, upon its approval of the Merger Agreement, shall direct that the Merger Agreement be submitted to a vote of Limited Partners, whether at a special meeting or by written consent, in either case in accordance with the requirements of Article XIII. A copy or a summary of the Merger Agreement shall be included in or enclosed with the notice of a special meeting or the written consent.

(b) Except as provided in Section 14.3(d), the Merger Agreement shall be approved upon receiving the affirmative vote or consent of the holders of a Unit Majority unless the Merger Agreement contains any provision that, if contained in an amendment to this Agreement, the provisions of this Agreement or the Delaware Act would require for its approval the vote or consent of a greater percentage of the Outstanding Units or of any class of Limited Partners, in which case such greater percentage vote or consent shall be required for approval of the Merger Agreement.

(c) Except as provided in Section 14.3(d), after such approval by vote or consent of the Limited Partners, and at any time prior to the filing of the certificate of merger pursuant to Section 14.4, the merger or consolidation may be abandoned pursuant to provisions therefor, if any, set forth in the Merger Agreement.

(d) Notwithstanding anything else contained in this Article XIV or in this Agreement, the General Partner is permitted, in its discretion, without Limited Partner approval, to merge the Partnership or any Group Member into, or convey all of the Partnership’s assets to, another limited liability entity which shall be newly formed and shall have no assets, liabilities or operations at the time of such Merger other than those it receives from the Partnership or other Group Member if (i) the General Partner has received an Opinion of Counsel that the merger or conveyance, as the case may be, would not result in the loss of the limited liability of any Limited Partner or any Group Member or cause the Partnership or any Group Member to be treated as an association taxable as a corporation or otherwise to be taxed as an entity for federal income tax purposes (to the extent not previously treated as such), (ii) the sole purpose of such merger or conveyance is to effect a mere change in the legal form of the Partnership into another limited liability entity and (iii) the governing instruments of the new entity provide the Limited Partners and the General Partner with the same rights and obligations as are herein contained.

Section 14.4 Certificate of Merger.

Upon the required approval by the General Partner and the Unitholders of a Merger Agreement, a certificate of merger shall be executed and filed with the Secretary of State of the State of Delaware in conformity with the requirements of the Delaware Act.

Section 14.5 Effect of Merger.

(a) At the effective time of the certificate of merger:

(i) all of the rights, privileges and powers of each of the business entities that has merged or consolidated, and all property, real, personal and mixed, and all debts due to any of those business entities and all other things and causes of action belonging to each of those business entities, shall be vested in the Surviving Business Entity and after the merger or consolidation shall be the property of the Surviving Business Entity to the extent they were of each constituent business entity;

(ii) the title to any real property vested by deed or otherwise in any of those constituent business entities shall not revert and is not in any way impaired because of the merger or consolidation;

(iii) all rights of creditors and all liens on or security interests in property of any of those constituent business entities shall be preserved unimpaired; and

(iv) all debts, liabilities and duties of those constituent business entities shall attach to the Surviving Business Entity and may be enforced against it to the same extent as if the debts, liabilities and duties had been incurred or contracted by it.

(b) A merger or consolidation effected pursuant to this Article shall not be deemed to result in a transfer or assignment of assets or liabilities from one entity to another.

ARTICLE XV

RIGHT TO ACQUIRE LIMITED PARTNER INTERESTS

Section 15.1 Right to Acquire Limited Partner Interests.

(a) Notwithstanding any other provision of this Agreement, if at any time more than 80% of the total Limited Partner Interests of any class then Outstanding is held by the General Partner and its Affiliates, the General Partner shall then have the right, which right it may assign and transfer in whole or in part to the Partnership or any Affiliate of the General Partner, exercisable in its sole discretion, to purchase all, but not less than all, of such Limited Partner Interests of such class then Outstanding held by Persons other than the General Partner and its Affiliates, at the greater of (x) the Current Market Price as of the date three days prior to the date that the notice described in Section 15.1(b) is mailed and (y) the highest price paid by the General Partner or any of its Affiliates for any such Limited Partner Interest of such class purchased during the 90-day period preceding the date that the notice described in Section 15.1(b) is mailed. As used in this Agreement, (i) “Current Market Price” as of any date of any class of Limited Partner Interests means the average of the daily Closing Prices (as hereinafter defined) per Limited Partner Interest of such class for the 20 consecutive Trading Days (as hereinafter defined) immediately prior to such date; (ii) “Closing Price” for any day means the

last sale price on such day, regular way, or in case no such sale takes place on such day, the average of the closing bid and asked prices on such day, regular way, in either case as reported in the principal consolidated transaction reporting system with respect to securities listed or admitted for trading on the principal National Securities Exchange (other than the Nasdaq Stock Market) on which such Limited Partner Interests of such class are listed or admitted to trading or, if such Limited Partner Interests of such class are not listed or admitted to trading on any National Securities Exchange (other than the Nasdaq Stock Market), the last quoted price on such day or, if not so quoted, the average of the high bid and low asked prices on such day in the over-the-counter market, as reported by the Nasdaq Stock Market or such other system then in use, or, if on any such day such Limited Partner Interests of such class are not quoted by any such organization, the average of the closing bid and asked prices on such day as furnished by a professional market maker making a market in such Limited Partner Interests of such class selected by the General Partner, or if on any such day no market maker is making a market in such Limited Partner Interests of such class, the fair value of such Limited Partner Interests on such day as determined reasonably and in good faith by the General Partner; and (iii) “Trading Day” means a day on which the principal National Securities Exchange on which such Limited Partner Interests of any class are listed or admitted to trading is open for the transaction of business or, if Limited Partner Interests of a class are not listed or admitted to trading on any National Securities Exchange, a day on which banking institutions in New York City generally are open.

(b) If the General Partner, any Affiliate of the General Partner or the Partnership elects to exercise the right to purchase Limited Partner Interests granted pursuant to Section 15.1(a), the General Partner shall deliver to the Transfer Agent notice of such election to purchase (the “Notice of Election to Purchase”) and shall cause the Transfer Agent to mail a copy of such Notice of Election to Purchase to the Record Holders of Limited Partner Interests of such class (as of a Record Date selected by the General Partner) at least 10, but not more than 60, days prior to the Purchase Date. Such Notice of Election to Purchase shall also be published for a period of at least three consecutive days in at least two daily newspapers of general circulation printed in the English language and published in the Borough of Manhattan, New York. The Notice of Election to Purchase shall specify the Purchase Date and the price (determined in accordance with Section 15.1(a)) at which Limited Partner Interests will be purchased and state that the General Partner, its Affiliate or the Partnership, as the case may be, elects to purchase such Limited Partner Interests, upon surrender of Certificates representing such Limited Partner Interests in exchange for payment, at such office or offices of the Transfer Agent as the Transfer Agent may specify, or as may be required by any National Securities Exchange on which such Limited Partner Interests are listed or admitted to trading. Any such Notice of Election to Purchase mailed to a Record Holder of Limited Partner Interests at his address as reflected in the records of the Transfer Agent shall be conclusively presumed to have been given regardless of whether the owner receives such notice. On or prior to the Purchase Date, the General Partner, its Affiliate or the Partnership, as the case may be, shall deposit with the Transfer Agent cash in an amount sufficient to pay the aggregate purchase price of all of such Limited Partner Interests to be purchased in accordance with this Section 15.1. If the Notice of Election to Purchase shall have been duly given as aforesaid at least 10 days prior to the Purchase Date, and if on or prior to

the Purchase Date the deposit described in the preceding sentence has been made for the benefit of the holders of Limited Partner Interests subject to purchase as provided herein, then from and after the Purchase Date, notwithstanding that any Certificate shall not have been surrendered for purchase, all rights of the holders of such Limited Partner Interests (including any rights pursuant to Articles IV, V, VI, and XII) shall thereupon cease, except the right to receive the purchase price (determined in accordance with Section 15.1(a)) for Limited Partner Interests therefor, without interest, upon surrender to the Transfer Agent of the Certificates representing such Limited Partner Interests, and such Limited Partner Interests shall thereupon be deemed to be transferred to the General Partner, its Affiliate or the Partnership, as the case may be, on the record books of the Transfer Agent and the Partnership, and the General Partner or any Affiliate of the General Partner, or the Partnership, as the case may be, shall be deemed to be the owner of all such Limited Partner Interests from and after the Purchase Date and shall have all rights as the owner of such Limited Partner Interests (including all rights as owner of such Limited Partner Interests pursuant to Articles IV, V, VI and XII).

(c) At any time from and after the Purchase Date, a holder of an Outstanding Limited Partner Interest subject to purchase as provided in this Section 15.1 may surrender his Certificate evidencing such Limited Partner Interest to the Transfer Agent in exchange for payment of the amount described in Section 15.1(a), therefor, without interest thereon.

ARTICLE XVI

GENERAL PROVISIONS

Section 16.1 Addresses and Notices.

Any notice, demand, request, report or proxy materials required or permitted to be given or made to a Partner or Assignee under this Agreement shall be in writing and shall be deemed given or made when delivered in person or when sent by first class United States mail or by other means of written communication to the Partner or Assignee at the address described below. Any notice, payment or report to be given or made to a Partner or Assignee hereunder shall be deemed conclusively to have been given or made, and the obligation to give such notice or report or to make such payment shall be deemed conclusively to have been fully satisfied, upon sending of such notice, payment or report to the Record Holder of such Partnership Securities at his address as shown on the records of the Transfer Agent or as otherwise shown on the records of the Partnership, regardless of any claim of any Person who may have an interest in such Partnership Securities by reason of any assignment or otherwise. An affidavit or certificate of making of any notice, payment or report in accordance with the provisions of this Section 16.1 executed by the General Partner, the Transfer Agent or the mailing organization shall be prima facie evidence of the giving or making of such notice, payment or report. If any notice, payment or report addressed to a Record Holder at the address of such Record Holder appearing on the books and records of the Transfer Agent or the Partnership is returned by the United States Postal Service marked to indicate that the United States Postal Service is unable to deliver it, such notice, payment or report and any subsequent notices, payments and reports shall be deemed to have been duly given or made without further mailing (until such time as such Record

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Holder or another Person notifies the Transfer Agent or the Partnership of a change in his address) if they are available for the Partner or Assignee at the principal office of the Partnership for a period of one year from the date of the giving or making of such notice, payment or report to the other Partners and Assignees. Any notice to the Partnership shall be deemed given if received by the General Partner at the principal office of the Partnership designated pursuant to Section 2.3. The General Partner may rely and shall be protected in relying on any notice or other document from a Partner, Assignee or other Person if believed by it to be genuine.

Section 16.2 Further Action.

The parties shall execute and deliver all documents, provide all information and take or refrain from taking action as may be necessary or appropriate to achieve the purposes of this Agreement.

Section 16.3 Binding Effect.

This Agreement shall be binding upon and inure to the benefit of the parties hereto and their heirs, executors, administrators, successors, legal representatives and permitted assigns.

Section 16.4 Integration.

This Agreement constitutes the entire agreement among the parties hereto pertaining to the subject matter hereof and supersedes all prior agreements and understandings pertaining thereto.

Section 16.5 Creditors.

None of the provisions of this Agreement shall be for the benefit of, or shall be enforceable by, any creditor of the Partnership.

Section 16.6 Waiver.

No failure by any party to insist upon the strict performance of any covenant, duty, agreement or condition of this Agreement or to exercise any right or remedy consequent upon a breach thereof shall constitute waiver of any such breach of any other covenant, duty, agreement or condition.

Section 16.7 Counterparts.

This Agreement may be executed in counterparts, all of which together shall constitute an agreement binding on all the parties hereto, notwithstanding that all such parties are not signatories to the original or the same counterpart. Each party shall become bound by this Agreement immediately upon affixing its signature hereto or, in the case of a Person acquiring a Unit, upon accepting the certificate evidencing such Unit or executing and delivering a Transfer Application as herein described, independently of the signature of any other party.

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Section 16.8 Applicable Law.

This Agreement shall be construed in accordance with and governed by the laws of the State of Delaware, without regard to the principles of conflicts of law.

Section 16.9 Invalidity of Provisions.

If any provision of this Agreement is or becomes invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained herein shall not be affected thereby.

Section 16.10 Consent of Partners.

Each Partner hereby expressly consents and agrees that, whenever in this Agreement it is specified that an action may be taken upon the affirmative vote or consent of less than all of the Partners, such action may be so taken upon the concurrence of less than all of the Partners and each Partner shall be bound by the results of such action.

[REMAINDER OF THIS PAGE INTENTIONALLY LEFT BLANK.]

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the parties hereto have executed this Agreement as of the date first written above.

GENERAL PARTNER:

MARKWEST ENERGY GP, L.L.C.

By:
	Name:	▇▇▇▇▇ ▇▇▇▇▇
	Title:	Senior Vice President and Chief Financial Officer


ORGANIZATIONAL LIMITED PARTNER:

MARKWEST HYDROCARBON, INC.

By:
	Name:	▇▇▇▇▇ ▇▇▇▇▇
	Title:	Senior Vice President and Chief Financial Officer

LIMITED PARTNERS:

All Limited Partners now and hereafter admitted as Limited Partners of the Partnership, pursuant to powers of attorney now and hereafter executed in favor of, and granted and delivered to the General Partner.

MARKWEST ENERGY GP, L.L.C.

By:
	Name:	▇▇▇▇▇ ▇▇▇▇▇
	Title:	Senior Vice President and Chief Financial Officer


MARKWEST HYDROCARBON, INC.
as successor by way of merger to
MARKWEST MICHIGAN, INC.

By:
	Name:	▇▇▇▇▇ ▇▇▇▇▇
	Title:	Senior Vice President and Chief Financial Officer

EXHIBIT A
to the Amended and Restated
Agreement of Limited Partnership of
MarkWest Energy Partners, L.P.
Certificate Evidencing Common Units
Representing Limited Partner Interests in
MarkWest Energy Partners, L.P.

No.

Common Units

In accordance with Section 4.1 of the Amended and Restated Agreement of Limited Partnership of MarkWest EnergyPartners, L.P., as amended, supplemented or restated from time to time (the “Partnership Agreement”), MarkWest EnergyPartners, L.P., a Delaware limited partnership (the “Partnership”), hereby certifies that (the “Holder”) is the registered owner of Common Units representing limited partner interests in the Partnership (the “Common Units”) transferable on the books of the Partnership, in person or by duly authorized attorney, upon surrender of this Certificate properly endorsed and accompanied by a properly executed application for transfer of the Common Units represented by this Certificate. The rights, preferences and limitations of the Common Units are set forth in, and this Certificate and the Common Units represented hereby are issued and shall in all respects be subject to the terms and provisions of, the Partnership Agreement. Copies of the Partnership Agreement are on file at, and will be furnished without charge on delivery of written request to the Partnership at, the principal office of the Partnership located at ▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇. Capitalized terms used herein but not defined shall have the meanings given them in the Partnership Agreement.

The Holder, by accepting this Certificate, is deemed to have (i) requested admission as, and agreed to become, a Limited Partner and to have agreed to comply with and be bound by and to have executed the Partnership Agreement, (ii) represented and warranted that the Holder has all right, power and authority and, if an individual, the capacity necessary to enter into the Partnership Agreement, (iii) granted the powers of attorney provided for in the Partnership Agreement and (iv) made the waivers and given the consents and approvals contained in the Partnership Agreement.

This Certificate shall not be valid far any purpose unless it has been countersigned and registered by the Transfer Agent and Registrar.

Dated:	MarkWest Energy Partners, L.P.

Countersigned and Registered by:	By:	MarkWest Energy GP, L.L.C., its General Partner

	By:
as Transfer Agent and Registrar	Name:

By:	By:
Authorized Signature	Secretary

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[Reverse of Certificate]

ABBREVIATIONS

The following abbreviations, when used in the inscription on the face of this Certificate, shall be construed as follows according to applicable laws or regulations:

TEN COM -	as tenants in common	UNIF GIFT/TRANSFERS MIN ACT
TEN ENT -	as tenants by the entireties		Custodian
		(Cust)		(Minor)
JT TEN -	as joint tenants with right of	under Uniform Gifts/Transfers to CD
	survivorship and not as	Minors Act (State)
	tenants in common

Additional abbreviations, though not in the above list, may also be used.

ASSIGNMENT OF COMMON UNITS
in
MARKWEST ENERGY PARTNERS, L.P.
IMPORTANT NOTICE REGARDING INVESTOR RESPONSIBILITIES
DUE TO TAX SHELTER STATUS OF
MARKWEST ENERGY PARTNERS, L.P.

You have acquired an interest in MarkWest EnergyPartners, L.P., ▇▇▇ ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇ ▇▇▇, ▇▇▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ ▇▇▇▇▇, whose taxpayer identification number is [ ]. The Internal Revenue Service has issued MarkWest EnergyPartners, L.P. the following tax shelter registration number: .

YOU MUST REPORT THIS REGISTRATION NUMBER TO THE INTERNAL REVENUE SERVICE IF YOU CLAIM ANY DEDUCTION, LOSS, CREDIT OR OTHER TAX BENEFIT OR REPORT ANY INCOME BY REASON OF YOUR INVESTMENT IN MARKWEST ENERGY PARTNERS, L.P.

You must report the registration number as well as the name and taxpayer identification number of MarkWest Energy Partners, L.P. on Form 8271. FORM 8271 MUST BE ATTACHED TO THE RETURN ON WHICH YOU CLAIM THE DEDUCTION, LOSS, CREDIT OR OTHER TAX BENEFIT OR REPORT ANY INCOME BY REASON OF YOUR INVESTMENT IN MARKWEST ENERGY PARTNERS, L.P.

If you transfer your interest in MarkWest EnergyPartners, L.P. to another person, you are required by the Internal Revenue Service to keep a list containing (a) that person’s name, address and taxpayer identification number, (b) the date on which you transferred the interest and (c) the name, address and tax shelter registration number of MarkWest EnergyPartners, L.P. If you do not want to keep such a list, you must (1) send the information specified above to the Partnership, which will keep the list for this tax shelter, and (2) give a copy of this notice to the person to whom you transfer your interest. Your failure to comply with any of the above-described responsibilities could result in the imposition of a penalty under Section 6707(b) or

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6708(a) of the Internal Revenue Code of 1986, as amended, unless such failure is shown to be due to reasonable cause.

ISSUANCE OF A REGISTRATION NUMBER DOES NOT INDICATE THAT THIS INVESTMENT OR THE CLAIMED TAX BENEFITS HAVE BEEN REVIEWED, EXAMINED OR APPROVED BY THE INTERNAL REVENUE SERVICE.

FOR VALUE RECEIVED, hereby assigns, conveys, sells and transfers unto


(Please print or typewrite name		(Please insert Social Security or other
and address of Assignee)		identifying number of Assignee)

Common Units representing limited partner interests evidenced by this Certificate, subject to the Partnership Agreement, and does hereby irrevocably constitute and appoint as its attorney-in-fact with full power of substitution to transfer the same on the books of MarkWest EnergyPartners, L.P.

Date:	NOTE:	The signature to any endorsement hereon must correspond with the name as written upon the face of this Certificate in every particular, without alteration, enlargement or change.
THE SIGNATURE(S) MUST BE
GUARANTEED BY AN ELIGIBLE
GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS		(Signature)
AND LOAN ASSOCIATIONS AND
CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C. RULE 17d-15		(Signature)

No transfer of the Common Units evidenced hereby will be registered on the books of the Partnership, unless the Certificate evidencing the Common Units to be transferred is surrendered for registration or transfer and an Application for Transfer of Common Units has been executed by a transferee either (a) on the form set forth below or (b) on a separate application that the Partnership will furnish on request without charge. A transferor of the Common Units shall have no duty to the transferee with respect to execution of the transfer application in order for such transferee to obtain registration of the transfer of the Common Units.

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APPLICATION FOR TRANSFER OF COMMON UNITS

The undersigned (“Assignee”) hereby applies for transfer to the name of the Assignee of the Common Units evidenced hereby.

The Assignee (a) requests admission as a Substituted Limited Partner and agrees to comply with and be bound by, and hereby executes, the Amended and Restated Agreement of Limited Partnership of MarkWest EnergyPartners, L.P. (the “Partnership”), as amended, supplemented or restated to the date hereof (the “Partnership Agreement”), (b) represents and warrants that the Assignee has all right, power and authority and, if an individual, the capacity necessary to enter into the Partnership Agreement, (c) appoints the General Partner of the Partnership and, if a Liquidator shall be appointed, the Liquidator of the Partnership as the Assignee’s attorney-in-fact to execute, swear to, acknowledge and file any document, including, without limitation, the Partnership Agreement and any amendment thereto and the Certificate of Limited Partnership of the Partnership and any amendment thereto, necessary or appropriate for the Assignee’s admission as a Substituted Limited Partner and as a party to the Partnership Agreement, (d) gives the powers of attorney provided for in the Partnership Agreement, and (e) makes the waivers and gives the consents and approvals contained in the Partnership Agreement. Capitalized terms not defined herein have the meanings assigned to such terms in the Partnership Agreement.

Date:


Social Security or other identifying number		Signature of Assignee


Purchase Price including commissions, if any		Name and Address of Assignee

Type of Entity (check one):

¨	Individual	¨	Partnership	¨	Corporation

¨	Trust	¨	Other (specify)

Nationality (check one):

¨	U.S. Citizen, Resident or Domestic Entity

¨	Foreign Corporation	¨	Non-resident Alien

If the U.S. Citizen, Resident or Domestic Entity box is checked, the following certification must be completed.

Under Section 1445(e) of the Internal Revenue Code of 1986, as amended (the “Code”), the Partnership must withhold tax with respect to certain transfers of property if a holder of an interest in the Partnership is a foreign person. To inform the Partnership that no withholding is

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required with respect to the undersigned interestholder’s interest in it, the undersigned hereby certifies the following (or, if applicable, certifies the following on behalf of the interestholder).

Complete Either A or B:

A. Individual Interestholder

1. I am not a non-resident alien for purposes of U.S. income taxation.

2. My U.S. taxpayer identification number (Social Security Number) is .

3. My home address is .

B. Partnership, Corporation or Other Interestholder

1. is not a foreign corporation, foreign partnership, foreign trust (Name of Interestholder) or foreign estate (as those terms are defined in the Code and Treasury Regulations).

2. The interestholder’s U.S. employer identification number is .

3. The interestholder’s office address and place of incorporation (if applicable) is .

The interestholder agrees to notify the Partnership within sixty (60) days of the date the interestholder becomes a foreign person.

The interestholder understands that this certificate may be disclosed to the Internal Revenue Service by the Partnership and that any false statement contained herein could be punishable by fine, imprisonment or both.

Under penalties of perjury, I declare that I have examined this certification and to the best of my knowledge and belief it is true, correct and complete and, if applicable, I further declare that I have authority to sign this document on behalf of:


	Name of Interestholder


	Signature and Date


	Title (if applicable)

Note: If the Assignee is a broker, dealer, bank, trust company, clearing corporation, other nominee holder or an agent of any of the foregoing, and is holding for the account of any other person, this application should be completed by an officer thereof or, in the case of a broker or dealer, by a registered representative who is a member of a registered national securities exchange or a member of the National Association of Securities Dealers, Inc., or, in the case of any other nominee holder, a person performing a similar function. If the Assignee is a broker, dealer, bank, trust company, clearing corporation, other nominee owner or an agent of any of the foregoing, the above certification as to any person for whom the Assignee will hold the Common Units shall be made to the best of the Assignee’s knowledge.

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AGREEMENT OF LIMITED PARTNERSHIP OF MARKWEST ENERGY PARTNERS, L.P.

Document Metadata

Document Metadata

Table of Contents

AGREEMENT OF LIMITED PARTNERSHIP OF MARKWEST ENERGY PARTNERS, L.P.

ARTICLE I

DEFINITIONS

Section 1.1 Definitions.

Section 1.2 Construction.

ARTICLE II

ORGANIZATION

Section 2.1 Formation.

Section 2.2 Name.

Section 2.3 Registered Office; Registered Agent; Principal Office; Other Offices.

Section 2.4 Purpose and Business.

Section 2.5 Powers.

Section 2.6 Power of Attorney.

Section 2.7 Term.

Section 2.8 Title to Partnership Assets.

ARTICLE III

RIGHTS OF LIMITED PARTNERS

Section 3.1 Limitation of Liability.

Section 3.2 Management of Business.

Section 3.3 Outside Activities of the Limited Partners.

Section 3.4 Rights of Limited Partners.

(i) to obtain true and full information regarding the status of the business and financial condition of the Partnership;

(ii) promptly after becoming available, to obtain a copy of the Partnership’s federal, state and local income tax returns for each year;

(iii) to have furnished to him a current list of the name and last known business, residence or mailing address of each Partner;

(v) to obtain true and full information regarding the amount of cash and a description and statement of the Net Agreed Value of any other Capital Contribution by each Partner and which each Partner has agreed to contribute in the future, and the date on which each became a Partner; and

(vi) to obtain such other information regarding the affairs of the Partnership as is just and reasonable.

ARTICLE IV

CERTIFICATES; RECORD HOLDERS; TRANSFER OF PARTNERSHIP INTERESTS; REDEMPTION OF PARTNERSHIP INTERESTS

Section 4.1 Certificates.

Section 4.2 Mutilated, Destroyed, Lost or Stolen Certificates.

(b) The appropriate officers of the General Partner on behalf of the Partnership shall execute and deliver, and the Transfer Agent shall countersign, a new Certificate in place of any Certificate previously issued if the Record Holder of the Certificate:

(i) makes proof by affidavit, in form and substance satisfactory to the General Partner, that a previously issued Certificate has been lost, destroyed or stolen;

(ii) requests the issuance of a new Certificate before the General Partner has notice that the Certificate has been acquired by a purchaser for value in good faith and without notice of an adverse claim;

(iv) satisfies any other reasonable requirements imposed by the General Partner.

Section 4.3 Record Holders.

Section 4.4 Transfer Generally.

(b) No Partnership Interest shall be transferred, in whole or in part, except in accordance with the terms and conditions set forth in this Article IV. Any transfer or purported transfer of a Partnership Interest not made in accordance with this Article IV shall be null and void.

(c) Nothing contained in this Agreement shall be construed to prevent a disposition by any member of the General Partner of any or all of the membership interests of the General Partner.

Section 4.5 Registration and Transfer of Limited Partner Interests.

(c) Limited Partner Interests may be transferred only in the manner described in this Section 4.5. The transfer of any Limited Partner Interests and the admission of any new Limited Partner shall not constitute an amendment to this Agreement.

(f) The General Partner and its Affiliates shall have the right at any time to transfer their Subordinated Units and Common Units (whether issued upon conversion of the Subordinated Units or otherwise) to one or more Persons.

Section 4.6 Transfer of the General Partner’s General Partner Interest.

(b) Subject to Section 4.6(c) below, on or after June 30, 2012, the General Partner may transfer all or any of its General Partner Interest without Unitholder approval.

Section 4.7 Transfer of Incentive Distribution Rights.

Section 4.8 Restrictions on Transfers.

(c) The transfer of a Subordinated Unit that has converted into a Common Unit shall be subject to the restrictions imposed by Section 6.7(b).

(d) Nothing contained in this Article IV, or elsewhere in this Agreement, shall preclude the settlement of any transactions involving Partnership Interests entered into through the facilities of any National Securities Exchange on which such Partnership Interests are listed for trading.

Section 4.9 Citizenship Certificates; Non-citizen Assignees.

(c) Upon dissolution of the Partnership, a Non-citizen Assignee shall have no right to receive a distribution in kind pursuant to Section 12.4 but shall be entitled to the cash equivalent

Section 4.10 Redemption of Partnership Interests of Non-citizen Assignees.

(iv) After the redemption date, Redeemable Interests shall no longer constitute issued and Outstanding Limited Partner Interests.

(b) The provisions of this Section 4.10 shall also be applicable to Limited Partner Interests held by a Limited Partner or Assignee as nominee of a Person determined to be other than an Eligible Citizen.

ARTICLE V

CAPITAL CONTRIBUTIONS AND ISSUANCE OF PARTNERSHIP INTERESTS

Section 5.1 Organizational Contributions.

Section 5.2 Contributions by the General Partner and its Affiliates.

(c) The General Partners shall contribute $1,600,000 as required by the Partnership to fund the construction and completion of the New ▇▇▇▇ Plant.

Section 5.3 Contributions by Initial Limited Partners and Distributions to the General Partner and its Affiliates.

Section 5.4 Interest and Withdrawal.

Section 5.5 Capital Accounts.

(iv) Any income, gain or loss attributable to the taxable disposition of any Partnership property shall be determined as if the adjusted basis of such property as of such date of disposition were equal in amount to the Partnership’s Carrying Value with respect to such property as of such date.

(c) (i) A transferee of a Partnership Interest shall succeed to a pro rata portion of the Capital Account of the transferor relating to the Partnership Interest so transferred.

Section 5.6 Issuances of Additional Partnership Securities.

Section 5.7 Limitations on Issuance of Additional Partnership Securities.

Capital Improvement is to be completed, would have resulted, on a pro forma basis, in an increase in:

(A) the amount of Adjusted Operating Surplus generated by the Partnership on a per-Unit basis (for all Outstanding Units) with respect to each of the four most recently completed Quarters (on a pro forma basis as described below) as compared to

(B) the actual amount of Adjusted Operating Surplus generated by the Partnership on a per-Unit basis (for all Outstanding Units) (excluding Adjusted Operating Surplus attributable to the Acquisition or Capital Improvement) with respect to each of such four most recently completed Quarters.

(f) No fractional Units shall be issued by the Partnership.

Section 5.8 Conversion of Subordinated Units.

(a) A total of 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2005, in respect of which:

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero.

(b) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2006, in respect of which:

Fully Diluted Basis, plus the related distribution on the General Partner Interest during such periods; and

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

provided, however, that the conversion of Subordinated Units pursuant to this Section 5.8(b) may not occur until at least one year following the conversion of Subordinated Units pursuant to Section 5.8(a).

(c) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2007, in respect of which:

(iii) the Cumulative Common Unit Arrearage on all of the Common Units is zero;

provided, however, that the conversion of Subordinated Units pursuant to this Section 5.8(c) may not occur until at least one year following the conversion of Subordinated Units pursuant to Section 5.8(b).

(d) An additional 1,200,000 of the Outstanding Subordinated Units will convert into Common Units on a one-for-one basis immediately after the distribution of Available Cash to Partners pursuant to Section 6.3(a) in respect of any Quarter ending on or after June 30, 2008, in respect of which:

CERTIFICATES; RECORD HOLDERS; TRANSFER OF PARTNERSHIP INTERESTS;
REDEMPTION OF PARTNERSHIP INTERESTS