On Tuesday, a three-judge panel of the U.S. Court of Appeals for the District of Columbia Circuit turned back every challenge to the Environmental Protection Agency's decision to place PFOA and PFOS, the two best-known forever chemicals, on the list of hazardous substances under the federal Superfund law. In *Chamber of Commerce v. EPA*, No. 24-1193, Judge Patricia Millett's unanimous opinion upheld a rule the agency finalized in May 2024, published at 89 Fed. Reg. 39124 in the Federal Register. The challengers, a coalition that included the U.S. Chamber of Commerce, the American Chemistry Council, the National Waste and Recycling Association, fuel producers, and construction contractors, argued the agency had no lawful basis for the listing. The court rejected every argument.
The decision also made legal history of a quiet kind. It was the first time the EPA had used Section 102 of the Comprehensive Environmental Response, Compensation, and Liability Act, the law known as CERCLA, to add a substance to the list by regulation. The list has existed since the statute was enacted in 1980, but until 2024 the agency had never worked that mechanism itself.
That detail matters more than it looks, because the practical situation is otherwise unchanged. The rule took effect on July 8, 2024, and no court suspended it during the two years of litigation over the listing. Since then, releases of the two compounds at or above one pound within 24 hours have had to be reported to the National Response Center, and the substances have been regulated as hazardous materials in transport. What the case really resolved was not whether the regime would begin, but whether it would survive. It survived.
The rule has been in force while the courts examined it
The listing changes the economics of cleanup, not the chemistry of commerce. It does not ban the manufacture or use of PFOA or PFOS. What it does is change who pays. Under CERCLA, once a substance is listed, the EPA, states, and private parties can recover cleanup costs from responsible parties, and the agency can act without first proving that a release poses an imminent and substantial danger. The entry also covers the compounds' salts and structural isomers, which is how a family of closely related chemicals comes in under one line on the list.
The EPA's own questions-and-answers page on the rule emphasizes how much the listing does not do. It orders no cleanup. It confers no automatic liability. It changes no one's status until a site is addressed and the question of who pays for it arises. The rule rests on the agency's finding that the two compounds may present a substantial danger to health, based on research linking them to effects that include certain cancers, developmental harm, and immune suppression. For the chemicals' manufacturers and heavy users, the meaning of the listing is straightforward: the cleanup bill that was previously a matter of negotiation is now a legal obligation that can be enforced by the government or by private parties.
The fight was over the route, not just the two names
Industry's central legal argument was that the EPA could designate a substance only if harm was certain to follow a release. The court, reading the statute itself under the Supreme Court's 2024 *Loper Bright* decision, which ended deference to agency interpretations of ambiguous law, held that the word "may" in the statutory phrase "may present substantial danger" means possibility, not proof. Demanding certainty about every individual release, the court wrote, would "legislatively paralyze CERCLA." It also found the agency's economic analysis reasonable, its notice adequate, and its approach within Congress's delegation of power.
That statutory holding is not confined to two compounds. The same language governs every substance that could ever be listed. Salts and isomers already ride along. And the family is large: the EPA says there are thousands of PFAS chemicals, used across consumer, commercial, and industrial products, and its own strategic roadmap insists that the forever chemical problem cannot be solved by tackling one use at a time.
Put the three facts together and the shape of the ruling becomes clear. The designation of PFOA and PFOS was, among other things, a test of whether the Section 102 route existed at all. It does. Adding other members of the family now becomes a rulemaking project, a matter of building a scientific and economic record, rather than a fight over whether the statute permits it. That is the difference between losing a battle and losing the war, and the industry groups that brought this case understand it. Their exposure was never really limited to two names on a list. It was always about whether the list could grow by regulation.
The ruling settles the ceiling, not the floor
It is just as important to say what Tuesday did not settle. The listing's practical reach is shaped by an enforcement memo, not by the statute. Two days after announcing the rule, the EPA issued its PFAS Enforcement Discretion and Settlement Policy, directing staff to focus on manufacturers and other parties that significantly contributed to releases, and stating that it does not intend to pursue community water systems, publicly owned treatment works, municipal landfills, municipal airports, local fire departments, and farms where biosolids are applied, where equitable factors do not support action.
That memo is guidance. It binds only the agency that issued it, and only until that agency changes its mind. It does not bind states. It does not stop private parties from suing. A water utility can still bring a cost-recovery claim against a manufacturer. A manufacturer can still face contribution claims from other responsible parties. The memo is not a legal defense; it is a statement of enforcement preference, and it can be narrowed by the same pen that wrote it.
The court also left open whether CERCLA even requires the EPA to consider costs when designating a substance, so the economics of future listings remain an open field for litigation. And the EPA itself has said it does not expect the number of sites on the National Priorities List to grow substantially because of the designation, since the chemicals already counted as pollutants for purposes of site listing. The rule's effect is to change the economics of existing sites, not to multiply them.
Both sides are already positioning for the next round
The immediate reactions tracked the stakes. The U.S. Chamber of Commerce's litigation arm called the rule "deeply flawed" and said the groups were considering an appeal, predicting costly litigation rather than efficient cleanups. The waste industry, which pushed the passive-receiver concern hardest, warned of "significant legal and financial uncertainty for passive receivers," the landfills and treatment plants that never manufactured the chemicals but handle them in ordinary waste. Earthjustice, representing community groups that intervened to defend the rule, called the decision "a major win for contaminated communities."
The politics of the case were not simple. The government defended the rule in court even after the administration changed in 2025, so this was not a fight between a regulator and its successor. And the contest has already moved beyond the courthouse. A proposed amendment to the next defense authorization bill would shield certain waste handlers from PFAS liability under Superfund; it has not passed. The largest private litigation over these chemicals, the firefighting foam multidistrict litigation, continues on its own track.
Neither side should read too much into a single ruling, and this analysis takes no position on whether the designation is wise policy. The costs the industry describes are real and well documented: parties that never made the chemicals face exposure to claims, and the enforcement memo's protections do not extend to private suits. The health stakes the rule rests on are real as well, and they are the reason the listing exists. Both deserve weight from the people making the next decisions.
The list is settled law now, and its use is the story
Tuesday's opinion converts a question of law into a question of administration. Before the ruling, the open question was whether the EPA could extend the Superfund list by regulation at all. After it, the list is settled law, and the interesting questions are about use: how the next rulemakings are built, what enforcement choices agencies make, what states do on their own, and how courts and insurers sort out who among many responsible parties pays. For companies, the lesson to copy is not the names of the two chemicals but the profile that put them there: persistence, toxicity, mobility, and a record of releases across the economy. For communities, the tool is confirmed, but a confirmed tool still needs someone to pick it up, and the cleanup depends on choices that no court opinion can compel. The chemicals themselves, being forever, will wait. The list is now a working instrument, and where it grows next is a question of use, not of law.
Primary sources
- Law360, Emily Field, August 18, 2026, for the headline event and the shape of the dispute.
- The D.C. Circuit's opinion in Chamber of Commerce v. EPA, No. 24-1193, as reported in coverage by E&E News, Notus, and Waste Dive, and summarized in law-firm alerts, for the holdings, the panel authorship, and the "legislatively paralyze CERCLA" language.
- The EPA's questions-and-answers page and the final rule at 89 Fed. Reg. 39124 for the one-pound reportable quantity, the salts-and-isomers scope, the first-use-of-Section-102 fact, and the agency's statements on enforcement and the National Priorities List, and the EPA's PFAS Enforcement Discretion and Settlement Policy page for the scope of that memo.
- The EPA's PFAS Explained and Strategic Roadmap pages for the scale of the class and the agency's approach, and the Earthjustice press release for the intervenors and their reaction.
- Waste Dive and Notus for the industry reaction quotes, the fact that the rule was never stayed, the administration's decision to defend the rule, and the pending congressional amendment.