On August 18, 2026, the D.C. Circuit handed EPA a clean win on one of the most consequential environmental rules of the decade. In Chamber of Commerce v. EPA, No. 24-1193, the court denied every petition challenging EPA’s 2024 rule designating PFOA and PFOS — two of the most common “forever chemicals” — as hazardous substances under CERCLA, the federal Superfund law.
EPA’s designation, which is now firmly in place, carries significant implications for companies that (knowingly or unknowingly) make, use, transport, or dispose of materials containing PFOA and PFOS. Here is what the Chamber of Commerce decision says and what it means going forward.
What the Court Decided
In 2024, EPA designated PFOA and PFOS as CERCLA hazardous substances, relying on research linking exposure to adverse health effects, including cancer and developmental delays. The Chamber of Commerce and other industry groups petitioned to vacate the rule. They raised three challenges, and the court rejected all of them.
- Statutory authority. The petitioners argued EPA could designate a substance only if harm was certain to follow a release. Reviewing the statute de novo under Loper Bright Enters. v. Raimondo, 603 U.S. 369 (2024), the court held EPA had the better reading: the word “may” refers to a possibility of substantial danger, not a certainty, and Congress wrote CERCLA to operate on scientific probabilities rather than absolute proof.
- Adequate notice. The court found EPA’s final cost-benefit analysis was a “logical outgrowth” of the economic assessment it had circulated for comment – indeed, EPA expanded that analysis in direct response to industry’s own comments.
- Reasoned decision-making. The court applied deferential “zone of reasonableness” review and upheld EPA’s cost and benefit estimates, its treatment of specific industries, and its decision to regulate despite acknowledged uncertainties. The court emphasized the deferential nature of arbitrary-and-capricious review and concluded that EPA had reasonably addressed those issues based on the information available to it.
The court also rejected petitioners’ constitutional arguments, finding no nondelegation or vagueness problem, reasoning that Congress supplied an intelligible principle tying EPA’s authority to a science-based public-health standard.
One potentially significant question remains unanswered: whether CERCLA actually requires EPA to consider costs when deciding whether to designate a hazardous substance in the first place. EPA assumed that it did for purposes of this rule, and the D.C. Circuit likewise assumed the requirement without deciding it.
What the Decision Means for Industrial Companies
The immediate legal effect is straightforward: PFOA and PFOS are confirmed hazardous substances under CERCLA, and the compliance and liability machinery that comes with that status applies.
That status carries some direct regulatory consequences. Among other things, releases above the applicable one-pound reportable quantity can trigger federal reporting requirements, and shipments above specified quantities are subject to hazardous-material transportation requirements.
The potentially larger concern for industrial companies, however, is CERCLA liability. Hazardous-substance status means that PFOA and PFOS can now form the basis for CERCLA response actions and cost-recovery claims. EPA may, after additional regulatory steps, compel responsible parties to undertake cleanup, while EPA, states, and private parties may potentially seek recovery of response costs under CERCLA.
Practical considerations for industry
Companies with current or historical connections to PFOA or PFOS should continue evaluating where those substances may intersect with their operations – not only through their own historical use, but through their connection to products, waste streams, wastewater, and other pathways.
The Chamber of Commerce opinion is particularly relevant to businesses that have not manufactured PFAS but may have received or handled PFAS-containing materials. The petitioners specifically raised concerns about downstream industries such as waste management, construction, and recycling. EPA responded, and the court noted, that CERCLA contains statutory defenses and limitations as well as mechanisms addressing parties responsible for comparatively small contributions.
As we have previously reported, EPA has noted that, under its enforcement discretion, it intends to prioritize manufacturers of PFAS in response actions, as opposed to passive receivers of PFAS. But companies evaluating their PFAS exposure should not assume that EPA’s current enforcement priorities eliminate potential liability – particularly because private parties and states may have independent avenues for pursuing claims.
Practical steps that companies should consider include:
- Evaluate potential PFAS risk. In consultation with counsel to ensure privileges and confidentiality are upheld, companies with historical PFOA or PFOS use should consider whether their operations, facilities, or waste streams present material CERCLA or release-reporting issues.
- Update transactional diligence. Purchasers and lenders should ensure that environmental due diligence appropriately considers potential PFOA/PFOS releases, particularly where a property’s historical uses involved PFAS, and evaluate with counsel and environmental professionals whether further investigation is warranted.
- Revisit contracts and insurance. Review indemnities, representations, and environmental cost-allocation provisions in acquisition, lease, and supply agreements, and evaluate how PFAS liabilities are treated under existing coverage.
- Preserve potential defenses. Companies should evaluate, with counsel, whether facts may support CERCLA defenses or liability limitations, including third-party, innocent-landowner, de minimis, or de micromis protections.
What’s Still Unsettled
The Chamber of Commerce ruling resolves the challenge to the PFOA/PFOS designation – but the broader PFAS legal landscape remains in motion. PFOA and PFOS are only two of more than 9,000 PFAS compounds, and questions remain about whether and how additional PFAS will be regulated by federal, state, and local authorities.
Among the questions that will continue to develop are how courts apply traditional CERCLA liability, causation, divisibility, allocation, and statutory defenses to PFAS scenarios; how entities that passively received PFAS through ordinary waste or wastewater streams will fare in CERCLA disputes; and how EPA’s enforcement policies interact with private-party and state claims.
Beyond CERCLA, PFAS litigation continues to expand. The federal AFFF MDL in South Carolina includes thousands of pending claims, with personal-injury claims moving toward bellwether trials. How those cases resolve – and whether PFAS litigation expands materially beyond AFFF into claims involving industrial releases, consumer products, and other exposure pathways – remains an important trend to watch.
Finally, it is possible that the Chamber of Commerce petitioners will seek review from the U.S. Supreme Court. Because the case involves a nationally significant EPA rule with potentially substantial consequences across multiple industries, it would not be surprising to see the Court grant certiorari.
For further questions regarding PFAS and regulation of other “forever chemicals,” contact Liskow attorney Michael Mims and visit our Environmental Practice Page.