(1) The authority granted by this chapter to the department for restricting the use of substitutes is supplementary to the department's authority to control air pollution pursuant to chapter 70A.15 RCW. Nothing in this chapter limits the authority of the department under chapter 70A.15 RCW.

(2) The department, in enforcing the requirements of this chapter, must adhere to the provisions applicable to the department under chapter 43.05 RCW regarding site inspections, technical assistance visits, notices of correction, and the issuance of civil penalties, to the extent that these provisions are not in conflict with federal requirements described in RCW 43.05.901.

(3) The department may elect to refrain from or cease administering or enforcing a requirement of this chapter if the United States environmental protection agency adopts requirements that:

(a) Are substantially duplicative of the requirements of this chapter and that negate the additional emission reduction benefits of state implementation of any requirement of this chapter; or

(b) Preempt state authority under this chapter.