Key Points:

• The D.C. Circuit granted 60-day stays in two lawsuits, allowing the U.S. Environmental Protection Agency to review and potentially rescind its 2024 rules regulating PFAS.
• The first rule stayed set maximum contaminant levels for six PFAS chemicals under the Safe Drinking Water Act.
• The second rule stayed designated two PFAS compounds — PFOA and PFOS — as hazardous substances under CERCLA (commonly known as Superfund).

Earlier in February, the D.C. Circuit granted a 60-day stay in a lawsuit against the U.S. Environmental Protection Agency over its April 2024 rule regulating six per- and polyfluoroalkyl substances (PFAS) under the Safe Drinking Water Act. (American Water Works Association and Association of Metropolitan Water Agencies v. Environmental Protection Agency et al., D.C. Circuit Court of Appeals Case No. 24-1188). As we previously explained, this rule set maximum contaminant levels (MCLs) for PFOA and PFOS at 4.0 nanograms per liter (ng/L) or parts per trillion (ppt), and PFHxS, PFNA, and HFPO-DA at 10 ng/L. It also maintained a controversial hazard index approach of 1 (unitless) as the MCL for any mixture containing two or more of these five PFAS chemicals, or PFBS.

Then, on February 24, the D.C. Circuit granted a 60-day stay in another lawsuit against the EPA over its designation of PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act, also known as CERCLA or Superfund. (Chamber of Commerce of the United States of America, et al., v. U.S. Environmental Protection Agency et al., D.C. Circuit Court of Appeals Case No. 24-1193.) As we previously reported, the designation requires current and past owners and operators of PFAS-contaminated property to investigate and remediate or remove the contamination. The designation also requires prospective property buyers to include a PFAS inquiry in Phase 1 environmental site assessments.

Both rules were identified in a December 5 letter from more than 100 manufacturing groups to then-President-elect Donald Trump concerning regulations the groups viewed as overly burdensome on various industries. By “pausing” these rulemakings and listings, President Trump may be indicating the EPA’s intent to follow the letter’s suggestion of taking “an incremental approach to PFAS that first addresses the higher risk non-polymer PFAS chemicals versus polymerized PFAS, which are much lower risk chemicals.” The EPA may do so by reviewing the two rules and deciding whether to rescind the new MCL standards and hazardous substance designations.