On August 18, 2026, the DC Circuit Court of Appeals upheld EPA’s 2024 rule designating PFOA and PFOS as “hazardous substances” under CERCLA.  The decision leaves EPA’s designation in place and confirms that PFOA and PFOS contamination can trigger CERCLA’s cleanup, cost-recovery, and liability framework.

PFOA and PFOS are two of the most widely used PFAS compounds and were historically used in consumer products and firefighting foams, including foams mandated for decades by the Federal Aviation Administration. EPA’s rule, which Kaplan Kirsch previously summarized here, gives EPA and private parties a CERCLA pathway to address qualifying PFOA and PFOS releases.

Industry petitioners, including the U.S. Chamber of Commerce and waste-management and chemical-industry groups, argued that EPA had not shown the substances “may present substantial danger” when released, as required by CERCLA § 102(a). The Court rejected that challenge, holding that EPA need not prove every release will cause substantial harm and may base a designation on evidence of potential danger under appropriate exposure circumstances.

The Court also rejected arguments that EPA failed to account for the rule’s economic consequences. It held that EPA was not required to predict or quantify every future CERCLA cleanup or private-party claim at the designation stage and credited EPA’s view that shifting cleanup costs from taxpayers to responsible parties is consistent with CERCLA’s purposes.

For regulated parties, the decision is significant but does not necessarily result in liability. CERCLA’s ordinary elements and defenses still apply, including potentially responsible party status, statutory defenses, landowner protections, apportionment, and allocation. But entities that manufactured or used PFAS-containing materials, arranged for PFAS waste disposal, or owned or operated affected properties should reassess potential CERCLA exposure, transactional risk, and available defenses.

The ruling may also affect cost-recovery and contribution disputes. EPA may use CERCLA authority to address qualifying PFOA and PFOS releases, including past releases, and public or private parties may seek recovery or contribution for qualifying cleanup costs. Recoverability of certain pre-designation PFOA/PFOS costs remains contested. EPA’s 2024 PFAS Enforcement Discretion and Settlement Policy contemplates enforcement discretion for certain public entities, but it may not protect those entities from private-party claims.

Petitioners may seek rehearing or Supreme Court review, so the litigation may continue. Unless the decision is stayed or reversed, however, EPA’s designation remains effective, and organizations with potential PFOA or PFOS issues should treat the ruling as an immediate compliance, litigation, and transactional due-diligence consideration.

Kaplan Kirsch regularly counsels clients, both public and private, on regulatory compliance, emerging contaminants, and strategies to comply with environmental laws and reduce environmental liability, and represents clients in related litigation. For more information about PFAS regulation, this litigation, or how PFAS regulation or liability may impact your organization, please contact Thomas A. Bloomfield, Polly Jessen, Bill Marsh, Sara Mogharabi, or Paul Caintic.