Toxicology Groups File Court Brief in Support of PFAS Drinking Water Rule Petitioners

On April 15, 2025, the Toxicology Excellence for Risk Assessment (TERA) and the International Society for Regulatory Toxicology and Pharmacology (ISRTP) filed an Amici Curiae Brief in the PFAS National Primary Drinking Water Regulation (NPDWR) litigation against EPA. The Brief was filed with the U.S. Court of Appeals for the District of Columbia Circuit in support of the petitioners (the American Water Works Association and the Association of Metropolitan Water Agencies, and the National Association of Manufacturers, American Chemistry Council, and The Chemours Company). The attorneys submitting the Brief on behalf of TERA and ISRTP include Susan Bodine, the former EPA enforcement chief under the first Trump administration.

TERA’s and ISRTP’s position is that EPA’s determination under the SDWA that PFOA and PFOS are found at levels of public health concern and the MCLs promulgated by EPA do not meet the requirements of the SDWA. They are not arguing that there should be no regulation of any PFAS chemicals, but that the maximum contaminant levels (MCLs) promulgated by EPA are too low. The reasons stated in the Brief include that:

• The studies relied on by EPA do not support EPA’s determinations.
• EPA’s risk assessments and evaluation of risks for PFOA and PFOS are inconsistent with international standards and scientific practices.
• EPA failed to abide by its chemical mixture guidelines when adopting a hazard quotient approach to setting MCLs.
• EPA failed to follow its own guidelines in its evaluation of carcinogenicity.
• EPA disregarded multiple guidelines when developing its reference dose.

For more information, read the Brief here.