A federal appeals court has granted the Environmental Protection Agency’s request for a 60-day abeyance in litigation challenging the Maximum Contaminant Levels (MCLs) for six PFAS chemicals.

In a February 7, 2025, decision, the U.S. Court of Appeals for the D.C. Circuit temporarily halted a lawsuit brought by the American Water Works Association and others. The plaintiffs challenge the MCLs set for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and hexafluoropropylene oxide dimer acid (HFPO-DA), published in the Federal Register on April 26, 2024.

EPA requested the abeyance to allow new leadership time to review the underlying rule. Just days after the D.C. Circuit ruling, on February 11, the EPA made a similar request to pause litigation over its designation of PFOA and PFOS as hazardous substances under CERCLA, a rule that was published on May 8, 2024. In its filing, the agency argued that courts have long recognized an administration’s ability to reassess regulations, especially following a change in leadership.

It remains unclear whether the EPA will take any action to revise its past decisions on PFAS MCLs or hazardous substance designations. Stay tuned for updates.

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