By: Heather Davis and Ned Witte

It’s been a busy week in the PFAS storm. On September 11, 2025, EPA moved to back away from regulating four PFAS substances under the Safe Drinking Water Act (SDWA), while preparing to defend Maximum Contaminant Levels (MCLs) for PFOA and PFOS. And just days later, after months of speculation, the agency confirmed it will take action to keep its authority to sue parties over PFAS cleanups. On September 17, 2025, EPA formally told the U.S. Court of Appeals for the D.C. Circuit that it will defend the challenge brought by the United States Chamber of Commerce, among other parties, to the Biden-era rule designating PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

The filing, made in Chamber of Commerce of the United States, et al. v. EPA, ensures that litigation over the rule will continue. EPA moved to lift the litigation abeyance and also asked the court to require the parties to submit a proposed schedule to continue briefing in this case by September 30.

EPA’s recent actions under the SDWA and CERCLA suggest the agency intends to keep PFOA and PFOS at the center of federal PFAS regulation, making them key drivers of cleanup obligations, liability, and enforcement.

Why EPA’s Defense of this Rule Matters

The CERCLA designation of PFOA and PFOS is unprecedented. While EPA has long added hazardous substances to the CERCLA list when those substances become regulated under other statutes, as provided by law, this is the first time EPA has used Section 102 authority to separately add substances to the CERCLA list. The move carries broad implications:

• Stronger PFAS cleanup authority. EPA, states, and private parties can compel remediation and recover cleanup costs more readily.
• Expanded PFAS liability. CERCLA’s strict, retroactive, and joint-and-several liability scheme means industries will continue to face far-reaching exposure for historical PFAS use.

If the EPA prevails in its defense of the rule, the designation ensures PFOA and PFOS remain at the forefront of the PFAS storm.

The Filing and the Press Release: Apparent Vacillation

EPA’s September 17 filing is procedural but significant. After five extensions keeping the case in abeyance since February, EPA announced it completed its internal review and decided to keep the rule in place.

The motion requested that the court lift the abeyance and set a new briefing schedule, noting that only a joint reply brief and final filings remain. Importantly, petitioners and intervenors did not oppose the motion, clearing the way for litigation to move forward.

EPA is no longer weighing options—it is prepared to defend the CERCLA designation.

Earlier this year, and as recently as late August, there were reports that some EPA staff were recommending repeal of the CERCLA PFAS designations. But Administrator Lee Zeldin’s September 17 press release, together with the court filing, affirms that the Administrator has made a decision.

In announcing his decision, Zeldin emphasized, as he has before, the “polluter pays” objective of this administration’s CERCLA enforcement, while reiterating the need for Congressional action to protect “passive receivers.” These may include utilities, landfills, wastewater systems and certain commercial airports required to meet FAA mandates related to AFFF (known as Part 139 Commercial Airports) — that risk being pulled into CERCLA liability despite not manufacturing or even intentionally using PFAS or being compelled by law to use PFAS for fire suppression.

The EPA press release states that in its decision to list PFOA and PFOS, the Biden Administration failed to articulate a framework for listing CERCLA hazardous substances. The press release identifies EPA’s commitment to establish such a framework through a rulemaking that will provide clear guidelines for future listings including how EPA will consider the costs of a listing.

What Stakeholders Should Do Now
EPA’s decision to defend the PFAS CERCLA rule signals that this is not a passing issue. Stakeholders should prepare for increased enforcement and litigation:

• Industry/manufacturers: Review historical PFAS use, assess insurance and indemnities, and prepare defenses for potential cost recovery actions.
• Passive receivers (utilities, landfills, wastewater facilities): Strengthen recordkeeping, track PFAS inputs, and continue advocating for Congressional protections.
• States and municipalities: Ready claims for cleanup cost recovery and monitor developments in the D.C. Circuit.
• Property purchasers: Establish a bona fide prospective purchaser defense when acquiring property that may be contaminated with PFOA or PFOS at any level.
• Counsel and advisors: Track deadlines, refine arguments on liability scope, and prepare for negotiations as cases move forward.

Stakeholders should take steps now to fortify their legal and operational positions in anticipation of heightened scrutiny and litigation.