EPA Designates PFOS and PFOA as Hazardous Substances

Alerts / September 9, 2022

On September 6, the United States Environmental Protection Agency (EPA) issued a notice of proposed rulemaking to designate perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund).[1] PFOA and PFOS are long-chain per- and polyfluoroalkyl substances (PFAS) with numerous oil-resistant, grease-resistant and water-resistant applications. PFOS and PFOA were voluntarily phased out of production by chemical manufacturers in the United States in 2002 and 2015. But they are now at the center of the EPA’s and the Biden administration’s PFAS regulatory efforts. PFOA and PFOS have been the subject of new health advisory levels (HALs) and proposed maximum contaminant limits (MCLs) under the Safe Drinking Water Act, proposed regulation as hazardous wastes under the Resource Conservation and Recovery Act (RCRA), and potential designation as hazardous air pollutants under the Clean Air Act.

The designation of PFOA and PFOS as hazardous substances under CERCLA may be the most consequential of all the new regulations, as it imposes potentially enormous environmental cleanup costs on municipal utilities, landfill owners and operators, and other potentially responsible parties, which could be liable for releases of the ubiquitous chemicals into the environment. The period for public comment on the EPA’s proposed rulemaking ends on November 7, 2022, and the rule could be finalized as soon as next year.

Unprecedented Designations and Unknown Costs

On October 18, 2021, the Biden administration and EPA Administrator Michael Regan announced the PFAS Strategic Roadmap, which laid out a whole-of-agency approach to addressing PFAS. The strategy included timelines by which the EPA planned to take specific actions, including designation of PFOA and PFOS as hazardous substances.[2] In January 2022, the EPA submitted its draft hazardous substances proposal to the White House Office of Management & Budget (OMB), where the rule lingered far past the typical 90-day review period. In mid-August, the OMB finally completed its review of the designated rule. The EPA released a pre-publication version of its rule in late August.

In the proposed rulemaking, the EPA admits that because it never before has “exercised its authority under CERCLA [S]ection 102(a), it has not previously issued an interpretation of the standard for designating hazardous substances.”[3] Notably, the rule states that “CERCLA Section 102(a) precludes consideration of cost” in making hazardous substance designations: “Congress did not list cost as a required or permissible factor, and none of the Congressionally-listed statutory factors encompass a consideration of cost.”[4] But despite the EPA’s interpretation of its own statutory authority, the OMB still designated the draft rule as “economically significant,” triggering a potential regulatory impact analysis (RIA) that requires the EPA to complete a rigorous cost-benefit analysis of the rule, including the rule’s direct and indirect costs.[5] The EPA released a draft economic assessment of the potential costs of the rulemaking, but no RIA appears to have been performed to date.[6] The draft economic assessment identifies certain direct reporting costs of the new rule, but it avoids any effort to quantify estimated cleanup costs that may be a consequence of the designation.

This proposed rule has potential indirect impacts that are important, but that pose significant challenges to quantification. Key information that would enable quantification is unavailable. Critical data that are missing include, among others (1) the number and types of sites that might need response activities along with information on the magnitude and extent of PFOA and PFOS contamination; (2) the cleanup standards that must be met by remedial activities; and (3) the technologies, and their associated costs, for assessing and remediating the various contaminated media at sites. EPA lacks information on the number of existing NPL sites that might face incremental costs to address PFOA or PFOS contamination, and on the number of new sites that might be identified as needing assessment or other response activities.[7]

As part of its effort to fill in these data gaps, the EPA has requested public comment specifically on these issues.[8] But it remains unclear whether the information the EPA obtains from the public will find its way into the final rule and/or a formal RIA.

Uncertain Science

In the draft rule, the EPA also explains that it interpreted the requirement that a substance “may present substantial danger to the public health" as an indication that Congress required neither certainty of a substantial danger nor proof of actual harm before designating a compound as a hazardous substance.[9] Indeed, much of the science that underpins the designations remains preliminary. In June 2022, the EPA replaced its 2016 lifetime HALs – which recommended drinking water exposures to PFOA and PFOS remain below 70 parts per trillion (ppt) – with new interim health advisory levels of .004 ppt for PFOA and .02 ppt for PFOS.[10] EPA’s Science Advisory Board recently critiqued these new standards, identifying “numerous instances in which the analyses and approaches in EPA’s documents could be revised to be more thorough and transparent.”[11] The EPA is expected to release proposed national primary drinking water regulations (MCLs) for PFOS and PFOA later this year, which will effectively replace the interim HALs.

Implications of Designating PFOS and PFOA Hazardous Substances

If the EPA’s rulemaking is finalized, there will be three immediate changes involving management of PFOS and PFOA under CERCLA:

  1. Any person in charge of a facility or vessel must immediately notify the National Response Center, state, or Tribal emergency response commissions, and the local or Tribal emergency planning committees when there is a release of PFOA or PFOS greater than one pound over a 24-hour period. (The EPA indicated that it may adjust the reportable quantities for these substances at a later date.) There are additional reporting requirements under the Emergency Planning and Community Right-to-Know Act. Owners of locations deemed PFOA or PFOS Superfund sites will be required to clean up those sites.
  2. The Department of Transportation will be obligated to list and regulate PFOA and PFOS as hazardous materials under the Hazardous Materials Transportation Act.
  3. When a federal agency sells or transfers federally owned real property, it must provide notice of when any PFOA or PFOS was stored for one year or more, known to have been released or disposed of.

By designating PFOA and PFOS as hazardous substances under CERCLA, the EPA has new authority to order cleanups (under Section 106) or recover costs from government cleanups of these substances (under Section 107). Private parties may also bring cost recovery actions for cleanups (also under Section 107) or actions for contribution to cleanup costs (under Section 113).

The EPA has indicated that it will not stop with PFOA and PFOS but is likely to list additional PFAS chemicals as hazardous substances – possibly including the short-chain replacement chemicals for PFOA and PFOS. Litigation of the current rulemaking appears near certain. Congress also may take action to mitigate the unintended consequences of a rule likely to ensnare many, including utilities, landfills and agricultural operations using biosolids or sludge.

[1] Designation of Perfluorooctanoic Acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) as CERCLA Hazardous Substances, 87 Fed. Reg. 54,415 (Sept. 6, 2022) (to be codified at 40 C.F.R. pt. 302).

[2] U.S. Environmental Protection Agency, “PFAS Strategic Roadmap: EPA’s Commitments to Action 2021-2024,” October 2021. (last visited 9/7/2022).

[3] See PFOA and PFOS Notice of Proposed Rulemaking at 54421.

[4] Id.

[5] Inside EPA, “OMB Deems PFAS CERCLA Rule ‘Significant,’ Triggering Impact Analysis,”, (last visited Sept. 7, 2022).

[6] An RIA typically includes (1) a statement of the need for the regulatory action; (2) a clear identification of a range of regulatory approaches; and (3) an estimate of the benefits and costs – both quantitative and qualitative – of the proposed regulatory action and its alternatives. Regulatory Impact Analysis: A Primer, Circular A-4, p. 1-2,

[7] U.S. Environmental Protection Agency, “Economic Assessment of the Potential Costs and Other Impacts of the Proposed Rulemaking to Designate Perfluorooctanoic Acid and Perfluorooctanesulfonic Acid as Hazardous Substances.” 2022, at 10-11, available at

[8] See PFOA and PFOS Notice of Proposed Rulemaking at 54439. See also EPA Economic Assessment at Section ES-5 p. 19.

[9] PFOA and PFOS Notice of Proposed Rulemaking at 54421.

[10] See PFOA and PFOS Notice of Proposed Rulemaking at 54430. This analysis is being reviewed by the EPA’s Science Advisory Board.

[11]  Science Advisory Board, transmittal of the Science Advisory Board Report titled “Review of EPA’s Analyses to Support EPA’s National Primary Drinking Water Rulemaking for PFAS,” Aug. 22, 2022,,18:P18_ID:2601#report (last visited Sept. 7, 2022).

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