On January 21, 2021, news provider Chemical Watch reported on a peer-reviewed rodent study by Conley et al., that found hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX; CAS 2062-98-8) to be a developmental toxicant in rats – similar to other per- and polyfluoroalkyl substances (PFAS).

The group of PFAS chemicals (FPF Dossier), including perfluorooctanesulfonic acid (PFOA; CAS 335-67-1) and (PFOS; CAS 1763-23-1), have widely been reported to be associated with various adverse health effects, e.g., metabolic and cardiovascular diseases and adverse developmental effects in fetuses and children (FPF reported).

The GenX technology utilizes HFPO-DA instead of PFOA as polymerization aid in fluoropolymer production. The substance was invented with the premise of being “less toxic” and having “fast clearance.” However, in the EU, HFPO-DA is listed as a substance of very high concern due to environmental persistence and mobility.

In the presented study, HFPO-DA exposure resulted in reduced pup birth weights, increased pup liver weight, and reduced neonatal survival at dose levels below those inducing overt maternal toxicities. Furthermore, peer-reviewed toxicity data are lacking for HFPO-DA, especially about its human half-life which may be “significantly longer […] than in rodents.”

The authors state that PFOA and HFPO-DA display similar activities and potencies and conclude that “the role that exposure to HFPO-DA or other PFAS play in the manifestation of human metabolic disorders deserves further attention given the strength of data in animal and epidemiological studies”.

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Emma Davies (January 21, 2021). “GenX has similar toxicity to PFOA, US EPA rodent study suggests.” Chemical Watch 


Conley et al. (October 27, 2021) “Hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX) alters maternal and fetal glucose and lipid metabolism and produces neonatal mortality, low birthweight, and hepatomegaly in the Sprague-Dawley rat.” Environment International