EPA Backs PFAS Hazardous Substance Designation Under CERCLA

On September 17, 2025, EPA ended months of uncertainty when the Department of Justice declared in a court filing that the government would continue to defend EPA’s rule designating two perfluoroalkyl substances, perfluorooctanoic acid (“PFOA”) and perfluorooctanesulfonic acid (“PFOS”), as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”).[1] The decision came after a seven-month abeyance in the litigation over the rule, which the court granted in order to allow the Trump EPA to review the Biden-era rule and determine EPA’s position and how to proceed in the case.

The rule, which took effect in July 2024, extends CERCLA’s broad and retroactive strict liability framework to PFOA and PFOS. EPA’s decision to stand behind the designations has significant and potentially costly implications for chemical manufacturers, manufacturers of products containing PFAS, waste management and wastewater treatment facilities, and real estate developers, among others.[2] 

On the day of the filing, EPA also announced that the agency intends to promulgate a framework rule to guide future hazardous substance designations under Section 102(a) of CERCLA.[3] The announcement responds to criticisms leveled at the PFOA and PFOS designation process and may portend additional process for any future designations.[4] EPA did not, however, use its plans for a future framework as grounds for reversing the existing designations. 

In an accompanying statement, EPA Administrator Zeldin acknowledged the challenges faced by so-called “passive receivers” of PFAS in feedstocks, products, waste, and other materials who may be exposed to liability for cleanup costs.[5] He stated that “EPA intends to do what [it] can based on [] existing authority” and called on Congress to provide new statutory language to “fully address [EPA’s] concerns with passive receiver liability.”[6]

Administrator Zeldin’s statement reinforces the fact that it would take a Congressional amendment to CERCLA to create new exemptions—including any exemption for passive receivers—from CERCLA’s liability scheme.

I. Background on the PFOA and PFOS Hazardous Substance Designation

On April 19, 2024, EPA issued a final rule designating PFOA and PFOS as hazardous substances under CERCLA.[7] CERCLA establishes strict, joint and several liability for: (1) owners and operators of facilities; (2) former owners and operators of facilities at the time hazardous substances were disposed; (3) any person who owned or possessed hazardous substances and arranged for their disposal or treatment at a facility; and (4) any person who transported hazardous substances to a facility.[8]

Under CERCLA, there are two ways a substance may be designated as hazardous. First, a substance is automatically designated as hazardous when it is identified as “hazardous” or “toxic” under the Clean Water Act, Clean Air Act, Safe Drinking Water Act, and Toxic Substances Control Act.[9] Second, EPA can promulgate regulations designating hazardous substances that “when released into the environment, may present substantial danger to the public health or welfare.”[10] The PFOA and PFOS designations mark the first time in the 45 year history of the statute that EPA has exercised its authority via the latter method. 

Designating PFOA and PFOS as hazardous substances under CERCLA is likely to increase costs at sites currently undergoing investigation or cleanup, add new CERCLA sites to the National Priority List, and potentially reopen cleanup remedies at sites where parties long ago may have resolved their liability in settlements with EPA. The designation is especially notable given the ubiquity of PFOA and PFOS in the environment and the fact that PFAS cannot be addressed using many of the common cleanup methods that may be effective with other contaminants.[11]

The U.S. Chamber of Commerce, lead petitioner in the ongoing litigation over the rule, estimated three years ago that the costs to assess and clean up PFOA and PFOS for potentially responsible parties (“PRPs”) would total over $17.4 billion or $900 million annually over 30 years for non-federal Superfund sites alone.[12] 

II. Litigation Challenging the PFOA and PFOS CERCLA Designation

Several industry groups have challenged the rule in the D.C. Circuit Court of Appeals.[13] Petitioners advance three main arguments that the rule should be vacated. 

First, petitioners argue that EPA’s interpretation of the statutory language “may present substantial danger” in Section 102(a) is too broad and is inconsistent with both the statutory structure and prior agency interpretation of Section 102(a).[14] Citing language from the Supreme Court’s decision in Loper Bright Enterprises v. Raimondo, petitioners argue that EPA’s interpretation of “may present substantial danger” contains no “fix[ed] boundary” to guide the agency’s decision-making and, therefore, cannot be the best reading of the statute.[15]

Second, petitioners raise several related arguments about EPA’s treatment of costs throughout the rulemaking process. They argue that EPA violated the Administrative Procedure Act’s (“APA”) notice-and-comment requirement by not disclosing its Regulatory Impact Analysis (“RIA”) until it published the Final Rule. Petitioners also contend that EPA’s consideration of costs was arbitrary and capricious because the agency ignored entire categories of costs, underestimated others, and miscategorized some costs as “benefits,” while mischaracterizing others as “indirect” and thus outside of the scope of the Regulatory Flexibility Act.[16] 

Third, petitioners argue that EPA’s decision to move forward with the rule despite significant uncertainty as to the consequences of the designation was arbitrary and capricious.[17] Specifically, they point to EPA’s conceded lack of certainty about (1) where PFOA and PFOS are located, and in what quantities; (2) what economic costs the Final Rule would impose; and (3) unintended consequences of designation. 

On February 11, 2025, EPA moved to hold the litigation in abeyance as agency leadership determined whether the final rule aligned with the new administration’s policy goals.[18] Such abeyances are common with changes in administration; however, conflicting statements by administration officials about the future of the rule increased uncertainty among the regulated community. Reporting from the New York Times in August 2025 suggested that EPA’s internal recommendation to the Administrator, as recently as July 2025, was to repeal rather than uphold the rule.[19]

With EPA’s decision to defend the rule, the litigation has resumed.[20] The parties must file a proposed briefing schedule by September 30, 2025, setting a deadline for Petitioners’ Reply brief.[21] 

III. PFAS Passive Receivers

EPA’s PFOA and PFOS designations do not contain exceptions for “passive receivers” of PFOA and PFOS. As a result, parties with these PFAS in their operations, on their land, and otherwise encountering uninvited PFAS are generally considered PRPs under CERCLA.[22] For example, municipal utilities face potential CERCLA liability because the chemicals are ubiquitous in wastewater, and PFAS can accumulate in biosolids that are disposed of in landfills or reused in agriculture. Indeed, a December 2022 letter from a coalition of drinking water, wastewater, and water reuse utility organizations to the U.S. Senate Committee on Environment and Public Works cautioned that the designation of PFOA and PFOS as hazardous substances would lead to an increase in CERCLA litigation against local utilities. ^[23]  Accordingly, utilities have urged EPA and Congress to establish a “safe harbor” that would protect utilities from CERCLA and other liability in light of the designation of PFOA and PFOS as hazardous substances.

Bipartisan legislation that would insulate passive receivers of PFAS from liability has been introduced in both the House and Senate in recent years.[24] Thus far, however, such bills have gained little traction. The last time CERCLA was substantively amended outside of an appropriations process was nearly twenty-five years ago when Congress enacted the Small Business Liability Relief and Brownfields Revitalization Act of 2001.[25] Substantive amendments to bedrock environmental statutes can be difficult to achieve as Congress is often wary of inviting renegotiation of existing statutes.

IV. How the PFOA and PFOS Hazardous Substance Designation Fits into EPA’s New PFAS Strategy 

EPA’s September 17 announcement is the latest in a series of regulatory developments related to PFAS. The agency has taken steps to roll back certain Biden-era PFAS rules and implement others under the Safe Drinking Water Act[26] and Toxic Substances Control Act,[27] and has promised to issue new PFAS regulations under the Clean Water Act.[28]

If you have any questions about the PFAS CERCLA designation or other PFAS regulations, please contact Jeff Kray, Jessica Ferrell, or Shannon Nelson for more information. 

[1] Motion to Govern, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. Sept. 17, 2025), No. 2135418.

[2] Designation of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) as CERCLA Hazardous Substances, 89 Fed. Reg. 39124, 39150, https://www.govinfo.gov/content/pkg/FR-2024-05-08/pdf/2024-08547.pdf 

[3] Env’t Prot. Agency, Trump EPA Announces Next Steps on Regulatory PFOA & PFOS Cleanup Efforts, Provides Update on Liability & Passive Receiver Issues (Sep. 17, 2025), https://content.govdelivery.com/accounts/USEPAAO/bulletins/3f31888.

[4] Id.

[5] Env’t Prot. Agency, Trump EPA Announces Next Steps on Regulatory PFOA & PFOS Cleanup Efforts, Provides Update on Liability & Passive Receiver Issues (Sep. 17, 2025), https://content.govdelivery.com/accounts/USEPAAO/bulletins/3f31888.

[6] Ellie Borst, EPA Backs Biden-Era “Forever Chemical” Superfund Rule, Greenwire (Sept. 18, 2025), https://subscriber.politicopro.com/article/eenews/2025/09/18/epa-backs-biden-era-forever-chemicals-superfund-rule-00571286.

[7] Designation of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) as CERCLA Hazardous Substances, 89 Fed. Reg. 39124, https://www.govinfo.gov/content/pkg/FR-2024-05-08/pdf/2024-08547.pdf. 

[8] 42 U.S.C. § 9607(a).

[9] 42 U.S.C. § 9601(14) (defining the term “hazardous substance” to include substances designated as hazardous or toxic under the Clean Water Act, Clean Air Act, Safe Drinking Water Act, and the Toxic Substances Control Act). 

[10] 42 U.S.C. § 9602(a).

[11] E.g., PFAS may need expensive Granular Activated Carbon (“GAC”) cleanup. 

[12] U.S. Chamber of Commerce, PFOS and PFOA Private Cleanup Costs at Non-Federal Superfund Sites 3 (June 2022), https://www.uschamber.com/assets/documents/PFOS-and-PFOA-Private-Cleanup-Costs-at-Superfund-Sites-6.8.22.pdf. 

[13] Petition for Review, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. June 10, 2024).

[14] Petitioner’s Opening Brief, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. Nov. 4, 2024).

[15] Id. at 30–33 (citing Loper Bright Enters. v. Raimondo, 144 S.Ct. 2244, 2263 (2024)).

[16] Id. at 51–71.

[17] Id. at 71–78.

[18] Motion to Hold Case in Abeyance, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. Feb. 11, 2025).

[19] Hiroko Tabuchi, An Industry Insider’s Changes at the EPA Could Cost Taxpayers Billions, N.Y. Times (Aug. 28, 2025), https://www.nytimes.com/2025/08/28/climate/steven-cook-epa-pfas-forever-chemicals.html. 

[20] Clerk’s Order Granting Motion to Govern Future Proceedings, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. Sept. 25, 2025).

[21] Motion to Govern, U.S. Env’t Prot. Agency, U.S Chamber of Com. v. Env’t Prot. Agency, No 24-1193 (DC Cir. Sept. 17, 2025).

[22] 42 U.S.C. § 9607(a).

[23] Coalition of Drinking Water, Wastewater, and Water Reuse Utility Organizations, Letter to U.S. Senate Comm. on Env’t & Public Works on Necessity of Protecting Water Systems from CERCLA Liability for PFAS (Apr. 28, 2022), https://www.ocwd.com/wp-content/uploads/119-support-letters.pdf. 

[24] Water Systems PFAS Liability Protection Act, H.R. 1267, 119th Cong. (2025); Agriculture PFAS Liability Protection Act of 2023, S. 1427, 118th Cong. (2023); Resource Management PFAS Liability Protection Act of 2023, S. 1429, 118th Cong. (2023); Water Systems PFAS Liability Protection Act, S. 1430, 118th Cong. (2023); Fire Suppression PFAS Liability Protection Act, S. 1432, 118th Cong. (2023),; Airports PFAS Liability Protection Act, S.1433, 118th Cong. (2023).

[25] Small Business Liability Relief and Brownfields Revitalization Act of 2001, H.R. 2869, 107th Cong. (2001) (enacted).

[26] Env’t Prot. Agency, EPA Announces It Will Keep Maximum Contaminant Levels for PFOA, PFOS (May 14, 2025), https://www.epa.gov/newsreleases/epa-announces-it-will-keep-maximum-contaminant-levels-pfoa-pfos.

[27] Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) Data Reporting and Recordkeeping Under the Toxic Substances Control Act (TSCA); Change to Submission Period, 90 Fed. Reg. 20236, https://www.govinfo.gov/content/pkg/FR-2025-05-13/pdf/2025-08168.pdf. 

[28] Env’t Prot. Agency, PFAS Requirements in NPDES Permit Applications, RIN 2040-AG34, Unified Agenda (Spring 2025), Agency Rule List - Spring 2025.