Disputes about environmental preemption usually make news in the context of disagreements over federal versus state statutory and constitutional authority. (Note that preservation of state power was probably the major final obstacle holding up Congressional passage of the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which reformed the federal Toxic Substances Control Act.) But preemption can also be a source of conflict between state and local governments. This was illustrated in a November 18, 2016, ruling by a three-judge panel of the U.S. Court of Appeals for the 9th Circuit.
The question before the panel was whether the County of Kauai, Hawaii, was legally empowered to issue and require compliance with its own set of regulations governing agricultural pesticides given that the state of Hawaii also has a regulatory program for pesticides. The panel found that the state’s regulatory program was comprehensive and that the state legislature requires uniform application of pesticide requirements statewide. Therefore, the panel concluded that Kauai’s regulations had no legal foundation and were preempted by the state regulations.