On February 2, 2022, EPA announced the release of the draft Integrated Risk Information System (IRIS) Toxicological Review of Perfluorohexanoic Acid (PFHxA) and Related Salts for a 60-day public comment period and external peer review. The proposed reference dose (RfD) places PFHxA’s toxicity in the middle of the pack of the PFAS assessments released in the past year.

This action represents the latest step toward EPA’s goal, as stated in its PFAS Strategic Roadmap, to better “understand human health and ecological toxicity across a wider variety of PFAS.” The IRIS Program is now developing a series of five PFAS toxicity risk assessments for PFBA, PFHxA, PFHxS, PFNA, PFDA, and their associated salts.

EPA plans to use the individual PFAS and PFAS mixtures toxicity testing to develop and refine PFAS categories, and inform future Agency programs such as site remediation, waterbody cleanups, and Toxic Substances Control Act (TSCA) new-chemicals review. The deadline for public comments is April 4, 2022.