Federal appellate courts are currently confronting pivotal questions about hazardous substance designations, cultural natural resource damages, and judicial oversight of U.S. Environmental Protection Agency (“EPA”) settlements.
D.C. Circuit to Hear PFAS CERCLA Hazardous Substance Designation
The U.S. Court of Appeals for the D.C. Circuit is scheduled to hear oral arguments in early 2026 in a high-profile case challenging the EPA’s designation of two per- and polyfluoroalkyl substances (“PFAS”)—perfluorooctanoic acid (“PFOA”) and perfluorooctanesulfonic acid (“PFOS”)—as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”) section 102. This marks the first time the EPA has used this provision to regulate a substance through rulemaking.
The case—Chamber of Commerce of the United States v. EPA—is drawing widespread attention due to its potential to set precedent for how PFAS are regulated and how CERCLA is interpreted going forward. The D.C. Circuit has scheduled oral arguments for January 20, 2026, emphasizing that the date is fixed unless modified by court order.
Although the rule designating PFOA and PFOS as CERCLA hazardous substances was finalized under the Biden administration, the Trump-era EPA has opted to defend it. However, industry challengers, led by the U.S. Chamber of Commerce and six other organizations, argue in a November 14 reply brief that the rule is legally flawed and cannot be salvaged by future regulatory reforms.
Specifically, they point to EPA’s admission that its interpretation of the phrase “may present substantial danger” lacks a clear regulatory framework. While the agency intends to issue a “Framework Rule” to guide future designations and incorporate cost considerations, the challengers argue that such efforts come “too late” to validate the current rule.
9th Circuit Considers Cultural NRD Claims in Cross-Border Dispute
In a parallel Superfund battle, the 9th Circuit is reviewing an en banc petition in Confederated Tribes of the Colville Reservation v. Teck Cominco Metals Ltd., where Canadian officials and industry groups are backing efforts to overturn a panel ruling that permitted Washington State tribal nations to seek natural resources damages (“NRD”) for cultural harms caused by toxic discharges into the Columbia River.
Teck Cominco, a Canadian mining firm, is seeking to avoid liability under CERCLA for releases from its smelter upstream in British Columbia. In amicus briefs filed in November, the Province of British Columbia and the Canadian Chamber of Commerce argue that applying CERCLA to cultural harms would violate Canadian sovereignty and expose foreign entities to sweeping liabilities under U.S. environmental laws. The Mining Association of Canada also joined in opposition.
A panel ruling in September allowed the Confederated Tribes to pursue claims that incorporate their unique cultural and spiritual ties to the Upper Columbia River, marking a significant expansion in how courts may interpret NRD liability under CERCLA.
3rd Circuit Weighs Judicial Oversight of Superfund Settlements
Meanwhile, the 3rd Circuit is assessing how much discretion courts should exercise in reviewing Superfund settlements, especially in light of recent Supreme Court decisions on agency deference. The case—USA v. Alden Leeds—involves a $150 million settlement approved by a New Jersey district court that allows a group of smaller potentially responsible parties (“PRPs”), known as the Small Parties Group (“SPG”), to avoid future liability for cleanup costs at the highly contaminated Diamond Alkali site.
Occidental Chemical Corp. (“OxyChem”), the largest PRP, is challenging the settlement, arguing that recent decisions—particularly the 2024 Loper Bright Enterprises v. Raimondo Supreme Court ruling that overturned Chevron deference—mean courts must more closely scrutinize EPA settlements.
SPG, in a brief filed on October 27, counters that the Loper Bright decision applies only to legal interpretations by agencies, not to the courts’ oversight of negotiated settlements. It further cites the Supreme Court’s 2025 National Environmental Policy Act ruling in Seven County Infrastructure Coalition v. Eagle County, which reaffirmed substantial deference to EPA’s discretionary settlement authority.
SPG also disputes arguments from Nokia of America, which was excluded from the settlement, asserting that its claims are premature. The case raises important questions about how EPA balances fairness and efficiency in securing cleanup funding from a wide array of responsible parties.
Takeaway
These cases are poised to redefine the contours of Superfund liability. The outcomes will not only influence how emerging contaminants like PFAS are regulated but also challenge the boundaries of judicial deference and international environmental accountability. Together, they signal a critical inflection point in the evolution of CERCLA—where scientific uncertainty, legal interpretation, and cross-border implications converge to reshape environmental governance in the United States.
