EPA issued a final toxicity assessment for the PFAS GenX chemicals (aka hexafluoropropylene oxide (HFPO) dimer acids or HFPO-DA).
Within associated fact sheets, EPA affirmed that they will be revising their toxicity assessments for PFOA and PFOS (no date provided), and that by Spring of 2022, they will be issuing drinking water health advisories for PFBS and GenX chemicals.
https://www.epa.gov/system/files/documents/2021-10/genx-final-tox-assess-tech-factsheet-2021.pdf
GenX falls within the small subgroup of PFAS called per- and polyfluoroalkyl ether carboxylic acids (PFECAs). GenX is often dubbed “short chain” and “replacement chemistry” because it was made to replace PFOA in the manufacturing process for polymers. According to EPA’s new toxicity assessment, the chemical has similar toxicity concerns as PFOA and PFOS. GenX (HFPO-DA) is included in EPA’s drinking water methods and standard analyte lists from commercial labs. It is not expected to be present at sites associated with aqueous film-forming foam (AFFF), however, because it is not used as an ingredient in foam.
