1.    Consistent with the federal Clean Air Act [42 U.S.C. § 7401 et seq.] and the regulations adopted under the Clean Air Act, the department shall develop and implement a state regional haze plan in accordance with this section.

2.    The state regional haze plan must include an analysis of the natural and international causes of visibility impairment.

3.    In developing a periodic comprehensive revision of the state implementation plan, the department shall consider whether additional measures are necessary to make reasonable progress toward meeting the national goal of visibility improvement, as required by the federal Clean Air Act [42 U.S.C. § 7401 et seq.] and further defined by the United States environmental protection agency to be natural visibility conditions by 2064. The department may not require controls the department has determined serve only to increase total costs with little corresponding visibility benefit.

4.    If the environmental protection agency disapproves the state regional haze plan, the department may develop and submit as expeditiously as possible a revised plan to address the reasons for the disapproval in accordance with the requirements of this section.

5.    Any new control measures mandated by the state regional haze plan are effective only upon final approval by the environmental protection agency.

6.    If federal laws, a federal court, or a final federal agency action renders any control measures included in the state plan unenforceable by the environmental protection agency, the requirement to implement the measures may not be enforced under state law to the same extent the measures are unenforceable under federal law.