Alert

Three Pending Superfund Appeals Could Shape CERCLA’s Future Application

November 20, 2025

Federal appellate courts are currently confronting pivotal questions about hazardous substance designations, cultural natural resource damages, and judicial oversight of 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 PFAS—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)—as hazardous substances under 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 et al. 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 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 Nov. 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, where Canadian officials and industry groups are backing efforts to overturn a panel ruling that permitted Washington State tribes 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, et al. — 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 ruling that overturned Chevron deference — mean courts must more closely scrutinize EPA settlements.

SPG, in a brief filed Oct. 27, counters that the Loper decision applies only to legal interpretations by agencies, not to the courts’ oversight of negotiated settlements. They further cite the 2025 NEPA 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.

Summary of Emerging Legal and Policy Themes:

• PFAS Hazard Designations: The D.C. Circuit will determine whether EPA’s use of CERCLA §102 to designate PFAS as hazardous substances can withstand industry challenges.
• Cultural NRD Claims: The 9th Circuit may redefine the scope of CERCLA liability by deciding whether cultural resource damages are recoverable, even across international borders.
• Judicial Deference to Settlements: The 3rd Circuit’s review of the Diamond Alkali settlement may set precedent for how courts evaluate complex Superfund cost allocations following major Supreme Court rulings.

These cases reflect growing tensions between environmental protection, regulatory authority, international comity, and the limits of judicial deference—issues likely to shape CERCLA’s future application across multiple dimensions.

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.