On June 28, 2024, in its decision in Loper Bright Enterprises, et al. v. Raimondo, et al., the U.S. Supreme Court held that its longstanding precedent granting deference to administrative agencies established in the 1984 Supreme Court decision, Chevron U.S.A. Inc. v. National Resources Defense Council, Inc., 467 U.S. 837, went too far.  The Court held that the role of a reviewing court is to independently interpret the statute and to mark the boundaries of the authority delegated to the agency and ensure that the agency engaged in reasoned decision making within those boundaries. The Court concluded that Chevron had become an impediment, rather than an aid, to accomplishing the basic judicial task of saying what the law is. A summary of the Loper Bright decision can be found here.  It remains to be seen how Loper Bright may impact challenged actions of the EPA including regulation of PFAS. There are various challenges to PFAS regulations currently pending. The National Association of Manufacturers (NAM) and American Chemistry Council (ACC) have filed  a challenge to EPA’s Maximum Contaminant Levels (MCLs) for six PFAS.  The American Water Works Association (AWWA) and Association of Metropolitan Water Agencies (AMWA) have also challenged the MCLs. The U.S. Chamber of Commerce and other parties have filed a challenge to EPA’s designation of PFOA and PFOS as hazardous substances. It will be interesting to see how the petitioners use Loper Bright in their arguments against EPA’s regulation. We are monitoring these cases and will provide updates as the cases progress, including whether Loper Bright is raised and how the reviewing court responds.