A federal appeals court has upheld EPA’s designation of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), including their salts and structural isomers, as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The decision leaves intact a landmark rule that brings two of the most prominent per- and polyfluoroalkyl substances (PFAS) within CERCLA’s stringent cleanup, enforcement, cost recovery, and release-reporting framework.
The ruling is significant for companies across the manufacturing, chemical, waste management, wastewater, real estate, and remediation sectors because CERCLA liability can be strict, joint and several, and retroactive. The court’s decision ensures that the hazardous substance designation remains in force unless Congress or EPA takes further action.
Background
In April 2024, EPA finalized a rulemaking designating PFOA and PFOS as hazardous substances under CERCLA. The rule, which became effective in July 2024, was the first time EPA used CERCLA Section 102(a) to designate substances as hazardous through rulemaking rather than relying on designations made under other environmental statutes.
Shortly after the rule was promulgated, several industry groups led by the U.S. Chamber of Commerce challenged EPA’s action in the U.S. Court of Appeals for the D.C. Circuit. In February 2025, the court granted EPA’s request to hold the case in abeyance while the incoming Trump Administration reviewed the designation. In September 2025, EPA announced that it would retain the hazardous substance designation for PFOA and PFOS and defend the rule in court.
The D.C. Circuit’s Decision
The D.C. Circuit rejected the industry challenge and upheld EPA’s designation. The court concluded that EPA had adequately considered the scientific and regulatory record before it and reasonably explained why designation was appropriate at this initial stage despite acknowledged uncertainties.
The decision affirms EPA’s authority to designate substances under CERCLA Section 102(a) where the agency determines that their release “may present substantial danger” to public health, welfare, or the environment. It also signals judicial deference to EPA’s reasoned decision-making in the PFAS context, particularly where the agency acknowledges uncertainty but explains why precautionary regulation is warranted based on the record.
Practical Implications for Regulated Entities
- Expanded release-reporting obligations. Facilities must evaluate whether releases of PFOA or PFOS meet or exceed applicable reportable quantities and, where required, provide immediate notice to the National Response Center and appropriate state, Tribal, local, or Tribal emergency response authorities.
- Greater cleanup and cost-recovery exposure. EPA and other agencies with CERCLA authority may use the designation to compel new or reopen existing response actions, recover cleanup costs, and pursue potentially responsible parties in connection with PFOA and PFOS contamination.
- Increased transactional and site diligence focus. Buyers, sellers, lenders, landlords, and developers should expect heightened scrutiny of PFAS risks during environmental due diligence, property transfers, brownfield redevelopment, and remediation planning.
- Continuing uncertainty for passive receivers. EPA has recognized concerns for entities that did not manufacture or intentionally generate PFOA or PFOS but may nevertheless face CERCLA exposure (e.g., water utilities, municipal landfills, etc.). However, absent statutory amendments or further agency action, the designation remains enforceable.
- Potential contribution and allocation disputes. The decision may accelerate private-party cost recovery and contribution claims involving historical PFAS use, disposal, waste handling, wastewater treatment, and contaminated property.
Key Takeaway
The D.C. Circuit’s decision confirms that PFOA and PFOS remain CERCLA hazardous substances, preserving EPA’s ability to require reporting, compel cleanups, and shift cleanup costs to potentially responsible parties. Companies with current or historical connections to PFOA, PFOS, PFAS-containing materials, wastewater, waste disposal, or contaminated real property should evaluate their risk profile now and prepare for increased enforcement, diligence, and private-party litigation activity.
