PFAS Developments: CERCLA Designations Stay Intact For Now, Rollbacks Under SDWA

The regulation of per- and polyfluoroalkyl substances (PFAS) continues to evolve under the Trump administration, with the EPA making three important announcements last month. The agency intends to keep the existing hazardous substance designations under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for PFOA and PFOS, but is seeking to modify PFAS regulations promulgated under the Safe Drinking Water Act (SDWA). And as reported in the Office of Management and Budget's biannual Regulatory Unified Agenda, EPA intends to pursue several other PFAS-related actions in the coming months.

PFOA and PFOS Will Remain "Hazardous Substances" Under CERCLA

In July 2024, a rule designating two widely used PFAS—perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)—as "hazardous substances" under CERCLA went into effect. As explained in a prior blog post, the 2024 rule includes strict reporting requirements under CERCLA and the Emergency Planning and Community Right-to-Know Act (EPCRA) and requires notice be given to potential injured parties of any releases by owners or operators of vessels or facilities. Perhaps more importantly, it enables parties to recover response costs for cleanup of those compounds from other responsible parties. Since President Trump took office in 2025, the administration had stated it was reviewing the 2024 rule for possible repeal. On September 17, 2025, EPA confirmed that PFOA and PFOS will remain "hazardous substances" under CERCLA.

In addition to retaining these requirements, EPA announced that it intends to track the rule, including its costs and benefits, and may seek to amend CERCLA to exclude "passive receivers" from liability under the statute. So-called "passive receivers" are entities that did not manufacture or generate hazardous substances but instead received them in certain products and waste. EPA also announced that it will initiate rulemaking to establish a uniform designation of hazardous substances under CERCLA, which would be used to potentially designate other PFAS compounds in the future.

EPA Seeks to Roll Back Enforcement of PFAS Regulations Under SDWA

In April 2024, EPA finalized a rule regulating six PFAS compounds and certain PFAS mixtures under the SDWA. On September 11, 2025, EPA took steps to advance its May 2025 promise that it would try to roll back part of that rule. In litigation brought by the American Water Works Association (AWWA) and the Association of Metropolitan Water Agencies (AMWA) challenging the 2024 rule, discussed in a prior blog post, EPA asked the D.C. Circuit to invalidate a portion of the agency's 2024 rule regulating PFAS on the grounds that "parts of the rulemaking process [setting those limits] were unlawful."

Specifically, EPA asked the court to vacate the agency's determination to regulate three PFAS compounds individually (perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and hexafluoropropylene oxide dimer acid (HFPO-DA)), mixtures of those three PFAS compounds, and mixtures of a fourth PFAS compound (perfluorobutane sulfonic acid (PFBS)). EPA also asked the court to vacate the Maximum Contaminant Level Goals and Maximum Contaminant Levels (MCLs) EPA set for those PFAS compounds and mixtures under the 2024 rule. EPA claims that it violated SDWA's statutorily prescribed procedure by not seeking public comment on the agency's preliminary regulatory determination regarding those PFAS compounds and mixtures before proposing a regulation setting goals and standards for those PFAS. EPA instead proposed and finalized the regulatory determination and regulation simultaneously.

Despite its requested rollbacks regarding PFNA, PFHxS, HFPO-DA, and PFBS, EPA made clear in that same court filing that it intends to defend the portions of the 2024 rule governing PFOA and PFOS because the agency believes it followed the correct process when it promulgated the portion of the rule setting MCLs for those PFAS. The court has not yet issued a decision on EPA's request.

Anticipated PFAS Developments

On September 4, 2025, the Office of Management and Budget released its biannual Regulatory Unified Agenda, which outlines the actions federal agencies plan to take in the near and long term. This current agenda suggests that EPA intends to pursue several PFAS-related actions in the coming months including:

• Clarification to Supplier Notification Provision Due to Automatic Additions of PFAS Under the National Defense Authorization Act for Fiscal Year 2020 (NDAA): EPA is editing its Toxic Release Inventory (TRI) regulation to explicitly include PFAS that are automatically added to the TRI chemical list pursuant to the NDAA in the regulation's definition of "toxic chemical." EPA intends to finalize this action in November 2025.

• Addition of Certain PFAS to the TRI: EPA is finalizing a proposed rule to add individually listed PFAS and PFAS categories to the TRI list of toxic chemicals subject to reporting under EPCRA and the Pollution Prevention Act (PPA). EPA intends to finalize this action by February 2026.

• Listing of Specific PFAS as Hazardous Constituents: EPA plans to finalize a rule proposed during the Biden administration to amend its regulation under the Resource Conservation and Recovery Act (RCRA) by adding nine specific PFAS, their salts, and their structural isomers, to RCRA's list of hazardous constituents. EPA intends to finalize this rule by April 2026.

• Extending the Compliance Deadline for the PFAS National Primary Drinking Water Regulation Rulemaking: EPA is proposing a new rule that will provide additional time for public water systems to meet the compliance deadlines for the MCLs in the National Primary Drinking Water Regulations for PFOA and PFOS. EPA intends to finalize this rule by April 2026.

• PFAS Data Reporting and Recordkeeping under the Toxic Substances Control Act (TSCA): EPA plans to propose certain exemptions and other modifications to its October 2023 regulation requiring manufacturers of PFAS in any year between 2011-2022 to report certain data to EPA related to exposure and environmental and health effects, including amending the data submission period. EPA intends to finalize these changes by summer 2026.

• Revisions to Effluent Guidelines to Address PFAS Discharges: EPA plans to revise (1) the Organic Chemicals, Plastics, and Synthetic Fibers Effluent Limitations Guidelines and Standards to address PFAS in discharges from facilities manufacturing PFAS, (2) the Metal Finishing Effluent Limitation Guidelines to address discharges of PFAS in wastewater from chromium electroplating facilities, and (3) the Landfills Effluent Limitation Guidelines to address discharges of PFAS in wastewater from landfills. EPA intends to propose these revisions by January 2026, July 2026, and March 2027, respectively.

• PFAS Requirements in National Pollutant Discharge Elimination System (NPDES) Permit Applications: EPA plans to update requirements for several of the existing NPDES permit application requirements to address monitoring and reporting of PFAS. EPA intends to complete this action by May 2027.

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