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Environmental Edge
April 13, 2023

Will EPA Be Designating Entire Categories of PFAS as CERCLA Hazardous Substances?

Environmental Edge: Climate Change & Regulatory Insights

The Environmental Protection Agency (EPA) is considering designating more PFAS (per- or polyfluoroalkyl substances) to the list of hazardous substances under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). On April 13, 2023, EPA issued an advance notice of proposed rulemaking (ANPRM) in which it is seeking public input and data to assist in its consideration of potentially designating as hazardous substances not just the seven specific PFAS identified in the notice by CAS Registry Numbers, but also “Categories of PFAS.” The implications of a broad category listing are noteworthy.

In September 2022, EPA published a proposed rule to designate PFOA and PFOS — two PFAS legacy chemicals — as CERCLA hazardous substances. That comment period is closed, and EPA is “in the process of reviewing public comments.” For an in-depth analysis of the potential impacts of listing PFAS chemicals as hazardous substances, see our earlier Advisory.

In this more recent notice, EPA is seeking input and data on whether the following compounds may present substantial danger to the public health or welfare or the environment:

  • Seven PFAS (besides PFOA and PFOS) and their salts and structural isomers, or some subset thereof, which include:
    • Perfluorobutanesulfonic acid (PFBS)
    • Perfluorohexanesulfonic acid (PFHxS)
    • Perfluorononanoic acid (PFNA)
    • Hexafluoropropylene oxide dimer acid (HFPO-DA)
    • Perfluorobutanoic acid (PFBA)
    • Perfluorohexanoic acid (PFHxA)
    • Perfluorodecanoic acid (PFDA)
  • Precursors to PFOA, PFOS, and other PFAS listed above
  • Categories of PFAS

Specifically, EPA is requesting “information concerning the characteristics of these compounds, such as mobility, persistence, prevalence, and other characteristics, that would supplement the existing toxicity data for these compounds.” According to the notice, EPA identified the seven compounds listed above “based on the availability of toxicity information previously reviewed by EPA and other Federal agencies.” EPA is also seeking information on other PFAS chemicals that it could consider designating as hazardous substances in the future, including “categories of PFAS.” This latter point of inquiry is telling and should not be overlooked.

The EPA’s recent notice states that its previously-proposed hazardous substance designations for PFOS and PFOA are based on a finding that those substances “may present substantial danger to the public health or welfare or the environment.” Moreover, the EPA’s invitation for additional information on the seven PFAS specified in the notice implies that the information the agency already has for these substances also could support such a finding, and that the general public might have data to support a similar finding for entire PFAS categories. Given the manner in which EPA has defined PFAS using a “structural definition” approach for purposes of its previous, and proposed, PFAS-related rulemakings under the Toxic Substances Control Act (TSCA), the scope of a follow-on CERCLA “categorical proposal” could have consequences spanning beyond the locations where the seven specifically-identified substances might be present in the environment.

Interested entities have until June 12, 2023 to submit comments on the proposal. Our team will continue to follow and report on developments in this area, including any final rulemaking by EPA to designate PFOA and PFOS as hazardous substances.

© Arnold & Porter Kaye Scholer LLP 2023 All Rights Reserved. This blog post is intended to be a general summary of the law and does not constitute legal advice. You should consult with counsel to determine applicable legal requirements in a specific fact situation.