The Other PFAS Shoe Drops: EPA Will Retain and Defend Its CERCLA PFAS Regulation

Responding to the D.C. Circuit’s deadline to inform the court how it wishes to proceed in litigation challenging the agency’s listing of two types of per- and polyfluoroalkyl substances (PFAS) as hazardous substances under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the Environmental Protection Agency (EPA) stood behind its rule. In a September 17, 2025 filing, EPA told the court that the Trump administration had completed its review and would ultimately keep the Biden-era CERCLA final rule in place. The agency also requested that the court remove—i.e. pause—the abeyance placed on the proceedings, so that the lawsuit could move forward and be adjudicated.

In an unusual move, EPA’s motion was accompanied by a declaration signed by John Evans, the principal deputy assistant administrator in the Office of Land and Emergency Management (OLEM), hinting that the administration would still seek to alter the regulatory framework for PFAS under CERCLA, but would do so instead through congressional engagement to shield liability for “passive receivers”—those entities that do not directly manufacture or generate PFAS but receive it through feedstocks, products, or waste. In a press release issued the same day as the filing, EPA Administrator Lee Zeldin doubled down on requests for congressional engagement, while also announcing EPA’s intent to develop a “CERCLA section 102(a) Framework Rule” aimed at codifying a “uniform approach to guide future hazardous substance designations, including how the agency will consider the costs of proposed designations.”

The decision to defend the rule came as a surprise to some, as just last week, EPA told the same court, in a separate proceeding, that it would abandon support for Biden-era regulations setting nation-wide maximum contaminant levels (MCLs) for four types of PFAS under the Safe Drinking Water Act. However, the agency did in that case determine that it would leave undisturbed the MCLs for PFOA and PFOS, the same two PFAS listed as hazardous substances in the CERCLA final rule. EPA also plans to extend the deadline for compliance with the PFOA and PFOS MCLs by an additional two years (from 2019 to 2031) as originally proposed under the Biden Administration.

Although it still remains to be seen whether either rule will survive judicial review, it appears that both will remain effective throughout the course of litigation. The Trump EPA has now confirmed that it intends to federally regulate at least some types of PFAS, and entities that suspect the presence of PFOA or PFOS in their wastewater, outfalls, or operations should begin preparing for compliance and potential CERCLA response actions.