Although we’re sure our readers are completely up to speed on the issue, we’ll still begin this rundown with a bit of background for those who have not been following the twists and turns of EPA’s recent review of GenX Chemicals. In October 2021, EPA issued its Toxicity Assessment for Hexafluoropropylene Oxide (HFPO), Dimer Acid, and its Ammonium Salt (otherwise known as GenX Chemicals), in which EPA proposed the lowest reference doses (RfDs) yet for any PFAS chemical: a chronic RfD of 0.003 µg/kg/day and a subchronic RfD of 0.02 µg/kg/day. At the time EPA issued its final GenX Chemicals Toxicity Assessment, it also announced that it was reevaluating its existing RfDs for PFOA and PFAS, which could move lower following the reassessment.

Fast forward to March of this year: a asserting that EPA’s GenX Chemicals Toxicity Assessment should be withdrawn and corrected, pursuant to the Information Quality Act, due to alleged deviations from standard EPA methodologies in performing such assessments. The claimed deviations range from improper reliance on various effects in animal studies to failing to undertake a proper review of the available literature. We’ll make sure to keep an eye out for EPA’s response to this petition.