Toxic or hazardous chemical means a substance that poses a serious danger to human health or the environment. (3) DUTIES AND POWERS OF THE DEPARTMENT OF HEALTH.—The department shall: (a) Adopt rules to administer ss. 381.0065- 381.0067, including definitions that are consistent with the definitions in this section, decreases to setback requirements where no health hazard exists, increases for the lot-flow allowance for performance-based systems, requirements for separation from water table elevation during the wettest season, requirements for the design and construction of any component part of an onsite sewage treatment and disposal system, application and permit requirements for persons who maintain an onsite sewage treatment and disposal system, requirements for maintenance and service agreements for aerobic treatment units and performance-based treatment systems, and recommended standards, including disclosure requirements, for voluntary system inspections to be performed by individuals who are authorized by law to perform such inspections and who shall inform a person having ownership, control, or use of an onsite sewage treatment and disposal system of the inspection standards and of that person’s authority to request an inspection based on all or part of the standards. (b) Perform application reviews and site evaluations, issue permits, and conduct inspections and complaint investigations associated with the construction, installation, maintenance, modification, abandonment, operation, use, or repair of an onsite sewage treatment and disposal system for a residence or establishment with an estimated domestic sewage flow of 10,000 gallons or less per day, or an estimated commercial sewage flow of 5,000 gallons or less per day, which is not currently regulated under chapter 403. (c) Develop a comprehensive program to ensure that onsite sewage treatment and disposal systems regulated by the department are sized, designed, constructed, installed, repaired, modified, abandoned, used, operated, and maintained in compliance with this section and rules adopted under this section to prevent groundwater contamination and surface water contamination and to preserve the public health. The department is the final administrative interpretive authority regarding rule interpretation. In the event of a conflict regarding rule interpretation, the State Surgeon General, or his or her designee, shall timely assign a staff person to resolve the dispute.