Unanimous D.C. Circuit Ruling Keeps PFOA and PFOS "Forever Chemicals" Within CERCLA's Reach
Key Takeaways
- On August 18, 2026, a unanimous D.C. Circuit panel kept perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)—two of the most common "forever chemicals"—inside the Comprehensive Environmental Response, Compensation, and Liability Act's (CERCLA) "hazardous substance" regime and rejected industry challengers' effort to vacate the U.S. Environmental Protection Agency's (EPA) designation.
- This means that EPA can now identify contaminated sites based on PFOA or PFOS contamination. It also raises the possibility that EPA can compel responsible parties to clean up or re-open contaminated sites while the United States or private parties can seek recovery of response costs.
- Parties engaging in real estate and corporate transactions involving properties with potential PFOA and PFOS contamination must pay close attention to the issue during due diligence and contract negotiations.
- The opinion marks the first major EPA rulemaking challenge in which a court applied Loper Bright. The decision shows that even without deference to an agency decision, independent judicial review does not necessarily upend a regulation when the statutory text is clear and the scientific record is substantial.
The Legal Challenge
Per- and poly-fluoroalkyl substances (PFAS) are a broad class of synthetic chemicals with myriad industrial applications, including nonstick cookware, waterproofing for carpet, furniture, clothing and packaging, and fire retardants. EPA has historically regulated these substances as "pollutants" or "contaminants" under CERCLA, requiring the high "imminent and substantial danger" threshold to be met before EPA could take action. However, in 2022, after evidence of their potential health risks increased, EPA proposed the more consequential step at issue here: designating PFOA and PFOS as “hazardous substances” under CERCLA. This broadens EPA's authority to take action in the event of a release that causes a "threat to public health or welfare."
In June 2024, seven industry groups representing companies that use, transport, discharge, or manufacture PFOA and PFOS petitioned the D.C. Circuit to set aside EPA's hazardous substance designation. They argued that EPA's interpretation of the term "hazardous substances" to include PFOA and PFOS was contrary to CERCLA's text; that the agency acted arbitrarily and capriciously in regulating despite uncertainty; and that EPA's cost-benefit analysis was both arbitrary and capricious and inadequately disclosed under the Administrative Procedure Act.
The D.C. Circuit's Decision
On August 18, 2026, a unanimous D.C. Circuit panel denied the petitions for review. The D.C. Circuit rejected petitioners' argument that, in order to list a substance as a hazardous substance under CERCLA, EPA must find that the release of a substance into the environment would result in harm, rather than that the release may result in harm. The D.C. Circuit rejected this reading, finding that a bright-line rule requiring that degree of certainty would "legislatively paralyze CERCLA." The court also rejected petitioners' arguments that EPA's decision-making process and cost-benefit analysis were arbitrary and capricious.
Significant Environmental Law Application of Loper Bright
The decision is notable because it marks the first time a court has applied Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024), to a major challenge to an EPA rulemaking. It is also the first time EPA has used CERCLA Section 102(a), 42 U.S.C. § 9602(a), to designate a hazardous substance.
In reviewing the phrase "may present substantial danger" in 42 U.S.C. § 9602(a), the court independently determined the statute's "best" reading by "applying all relevant interpretive tools," as Loper Bright requires. But it retained deferential arbitrary-and-capricious review of EPA's scientific findings, cost estimates, and technical judgments, citing FCC v. Prometheus Radio Project and Meritor, Inc. v. EPA. The decision confirms that under Loper Bright, courts decide statutory language but can still defer to the agency's technical work.
Next Steps
The D.C. Circuit retained jurisdiction over the matter, pending the resolution of any petitions for rehearing or petitions for rehearing by the full court. Additionally, given the significance of the rule, it remains possible that the petitioners may appeal the judgment to the Supreme Court. However, in the immediate term, this decision means that regulated entities may not rely on existing litigation to restrain EPA's enforcement under the rule.
Impacts
This rule has the potential to significantly impact entities in various sectors. As an example, EPA could review PFOA and PFOS in five-year reviews for existing sites, could re-open closed sites where PFOA and/or PFOS may be present, and could identify new CERCLA sites or require removals based solely on PFOA and PFOS. The industries most likely to be impacted include those involved in aviation, paper mills, landfills, firefighting training facilities, metal plating facilities, and textile coating operations. The rule may also impact industries that manufacture or use polymers, photographic film material, pesticides, and some medical devices.
The decision has the potential to impact PFAS rulemakings beyond CERCLA. For example, the decision likely bolsters EPA's Safe Drinking Water Act (SDWA) Maximum Contaminant Level (MCL) rules for PFOA and PFOS. In 2024, EPA issued a final rule regulating PFOA, PFOS, PFHxS, PFNA, HFPO-DA, and PFAS mixtures under the SDWA. While the Trump EPA has proposed rescission of MCLs for PFHxS, PFNA, HFPO-DA (GenX), and Hazard Index mixtures, it has indicated its intent to allow the final rule regulating PFOA and PFOS remain in place. Those MCLs rest on the same scientific record the D.C. Circuit relied on here. The SDWA rule is currently being litigated in the D.C. Circuit.
Stinson attorneys are closely monitoring this fast-moving landscape and the interaction among CERCLA, the SDWA, and PFAS litigation.
For more information on PFAS regulation, please contact Brittany Barrientos, Andrew Davis, Sarah Struby, Traci Cunningham, Betsy Moedritzer or the Stinson LLP contact with whom you regularly work.
