PFAS in water
The decision carries direct consequences for water utilities and other organisations that did not generate the contamination themselves.
The US Court of Appeals for the DC Circuit ruled on 18 August 2026 in Chamber of Commerce of the United States of America v. EPA.
The court denied consolidated industry petitions challenging the EPA’s 2024 designation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) as hazardous substances.
The chemicals are designated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), commonly known as Superfund.
A three-judge panel comprising Judges Patricia Millett, Gregory Katsas and Neomi Rao rejected the challenge on all three grounds raised.
Petitioners argued the EPA exceeded its statutory authority, failed to give adequate notice of its cost-benefit methodology, and acted arbitrarily given scientific uncertainty over future response costs.
The court found that CERCLA’s “may present substantial danger” standard requires only a scientifically supported possibility of serious harm, not certainty.
It also found the EPA’s rulemaking process met the Administrative Procedure Act’s notice requirements. The 2024 designation, and its reporting and liability consequences, remains fully in place.
The designation carries two direct, practical effects. First, any facility that releases one pound or more of PFOA or PFOS in a 24-hour period must immediately report that release.
Reports go to the National Response Center and to state, tribal and local emergency responders, under both CERCLA and the Emergency Planning and Community Right-to-Know Act.
Second, PFOA and PFOS now sit within CERCLA’s strict liability framework. Owners and operators of contaminated sites, and parties that transported or disposed of the chemicals, face investigation, cleanup costs and cost-recovery litigation.
That second consequence draws most attention from water utilities, wastewater treatment operators and landfill operators.
None of these manufacture PFOA or PFOS but each can receive the chemicals through incoming water, waste or sludge streams.
Industry groups describe these organisations as passive receivers: entities exposed to CERCLA liability despite having no role in producing the contamination.
The EPA issued a discretionary enforcement policy in 2024 stating an intention not to pursue passive receivers using its own enforcement tools.
That policy does not bind private cost-recovery litigation, and does not survive a change of administration.
This liability exposure is separate from, and independent of, the ongoing dispute over the EPA’s PFOA and PFOS drinking water limits under the Safe Drinking Water Act.
The CERCLA designation concerns contamination liability and cleanup cost recovery. The drinking water standard concerns permissible concentrations in tap water. Both can affect the same utility through different legal mechanisms.
Industry critics argue that treating PFOA and PFOS as, in the court’s words, just two more hazardous substances understates the scale of exposure, given how widely the chemicals have been used.
The American Chemistry Council and other groups may seek further review, though the panel’s decision remains in force unless and until that happens.
For laboratories and monitoring providers serving the water and environmental sectors, the ruling reinforces sustained demand for PFAS testing, site characterisation and long-term monitoring work.
Utilities and property owners are likely to step up efforts to assess their potential exposure ahead of any enforcement action.
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