PFAS Observer
On July 22, 2025, the U.S. Court of Appeals for the District of Columbia (D.C.) Circuit granted a motion by the Environmental Protection Agency (EPA) to lift the abeyance in consolidated litigation challenging the agency’s National Primary Drinking Water Regulation (NPDWR) for PFAS, finalized by the Biden administration in April of 2024.
EPA’s NPDWR for PFAS established six maximum contaminant levels (MCLs) for six PFAS compounds:
- PFOA and PFOS, regulated individually; and
- PFHxS, PFNA, HFPO-DA (GenX), and certain mixtures, regulated collectively.
Shortly after publication in 2024, multiple industry groups and water system stakeholders challenged the final rule in the D.C. Circuit. The briefing process began in late 2024 but remained incomplete when, following the inauguration of President Donald Trump in January 2025, EPA moved to pause the litigation to give the agency sufficient time to reconsider its regulatory approach. The Court granted EPA’s initial request to pause the case on February 7, 2025, and has since extended that pause three times.
In May of 2025, however, EPA announced its intent to (1) maintain its NPDWRs for PFOA and PFOS; but (2) rescind the NPDWR for hexafluoropropylene oxide dimer acid (HFPO-DA or GenX), perfluorononanoate (PFNA), and perfluorohexanesulfonic acid (PFHxS), as well as the hazard index used to evaluate the combined risk of those compounds and perfluorobutane sulfonic acid (PFBS). This announcement afforded EPA the ability to defend its revised position in Court.
On August 1, the parties submitted a joint request for a September 10 deadline for EPA to inform the Court of its position in the litigation and a September 17 deadline for a joint proposed briefing schedule.
Another challenge to a 2024 EPA rule regulating PFAS remains stayed. Earlier this month, the D.C. Circuit once again extended the abeyance in Chamber of Commerce of the United States v. EPA, Case No. 24-1193, a consolidated challenge to EPA’s final rule designating PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). This latest stay, which will last until August 18, follows multiple extensions since the court first granted abeyance in February 2025 to provide time for new EPA leadership to evaluate the rule and determine the agency’s litigation posture. In its most recent filing, EPA explained that its review remains ongoing and is being conducted “within the broader context of EPA’s comprehensive strategy to address PFOA and PFOS.” The agency emphasized that continuing the abeyance would promote judicial efficiency and conserve party resources if ultimately it elects to revise or rescind the rule.
We will continue to monitor these cases and report on any developments.
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