Drawing the Lines of PFAS Liability: What the Recent CERCLA Decision Means

For the manufacturers, transporters, waste handlers, and downstream users associated with these chemicals over the past eight decades, the ruling marks a dramatic shift. The cleanup bill is no longer exclusively the taxpayer’s problem.

Summary of the Opinion

The case arose after EPA designated two PFAS — PFOA and PFOS — as “hazardous substances” under CERCLA § 9602(a) in May 2024, citing scientific evidence linking the compounds to cancer, developmental effects, cardiovascular conditions, and other serious health harms. Seven industry groups (including the US Chamber of Commerce and American Chemistry Council (ACC)) petitioned for review, raising three primary challenges. 

Challenge 1: Statutory Interpretation of “May Present Substantial Danger” 

Petitioners argued that EPA’s reading of “may present substantial danger” was too broad and that the statute required a finding that harm “will” occur upon release. The court rejected the argument, holding that “may” carries its ordinary meaning of contingency or possibility and requiring scientific certainty would “legislatively paralyze CERCLA.”  The court also rejected nondelegation and void-for-vagueness challenges, finding that CERCLA provides an intelligible principle tying EPA’s authority to a science-based public health standard. 

Challenge 2: Adequacy of Notice for the Cost-Benefit Analysis

Petitioners argued that EPA’s final regulatory impact analysis differed so materially from the earlier economic assessment that it violated the Administrative Procedures Act’s notice requirement. The court held that the final analysis was a “logical outgrowth” of the economic assessment and proposed rule, especially because EPA had expressly solicited comments on whether to conduct a quantitative cost-benefit analysis, and the petitioners themselves had urged EPA to do just that. 

Challenge 3: Arbitrary and Capricious Claims

The court upheld EPA’s cost-benefit analysis across six sub-arguments regarding cleanup cost estimates at National Priorities List (NPL) sites, non-NPL sites, federal facilities, impacts on specific industries, benefit calculations, and treatment of small businesses. The court also rejected the argument that EPA could not regulate in the face of acknowledged uncertainties, extensively detailing the multi-step regulatory process that must occur before any party faces cleanup liability. 

Three Practical Takeaways for Affected Companies

1. CERCLA’s Full Liability Regime Now Applies to PFOA and PFOS, Including Cost-Recovery Actions

The designation shifts PFOA and PFOS from “pollutants or contaminants” (where the government bears cleanup costs from public funds) to “hazardous substances” (where EPA can compel responsible parties to clean up and recover costs from polluters). Practically, this means companies that have used, manufactured, transported, or disposed of PFOA and PFOS could now face potential cost-recovery enforcement actions under Section 107, Section 106 abatement orders, and contribution claims from other responsible parties. Companies should ensure that they are aware of their historical exposure to these chemicals across all operations, sites, and supply chains.

2. The Court Validated a Low Threshold for Future Designations, Expect Additional PFAS Compounds to Follow

The court endorsed EPA’s reading of “may present substantial danger” as requiring only a scientifically supported possibility of substantial harm, not certainty. This standard, combined with the court’s rejection of constitutional challenges, clears the path for EPA to designate additional PFAS compounds (beyond PFOA and PFOS) as hazardous substances using the same framework. Companies with exposure to the broader PFAS family should consider beginning proactive risk assessment and contamination mapping now, rather than waiting for additional designation rulemakings.

3. Liability Is Not Immediate; Companies Should Use the Multi-Step Process Strategically

The court extensively catalogued the many regulatory steps — Hazard Ranking System scoring, NPL listing through notice-and-comment rulemaking, site investigation, cost-effectiveness analysis, feasibility studies, and settlement procedures — that must occur before cleanup liability attaches to any party.  The court also highlighted CERCLA’s affirmative defenses (acts of God, third-party acts, de minimis/de micromis protections, innocent landowner defense). Companies should avail themselves of the opportunities to engage at each procedural stage — submitting comments during NPL listing proposals, participating in feasibility studies, and pursuing expedited settlements for de minimis contributions — rather than waiting passively for enforcement actions to ripen.