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Human Health Toxicity Assessments for GenX Chemicals

Related Links
  • EPA PFAS Strategic Roadmap
  • Final Human Health Toxicity Assessment for PFBS

EPA has finalized the human health toxicity assessment for Hexafluoropropylene Oxide (HFPO) Dimer Acid and its Ammonium Salt. HFPO dimer acid and its ammonium salt are also known as “GenX chemicals” because they are the two major chemicals associated with the GenX processing aid technology. GenX is a trade name for a processing aid technology used to make high-performance fluoropolymers without the use of perfluorooctanoic acid (PFOA).

The GenX chemicals toxicity assessment provides hazard identification, dose-response information, and derives toxicity values called oral reference doses (RfDs) for chronic and subchronic exposures. The assessment underwent external peer review and public comment. Policy makers can use the GenX chemicals toxicity assessment along with exposure information and other important considerations to determine if, and when, it is appropriate to take action to reduce exposure to GenX chemicals.

  • Fact Sheet: Human Health Toxicity Assessment for GenX Chemicals (pdf) (October 2021)
  • Technical Fact Sheet: Human Health Toxicity Assessment for GenX Chemicals (pdf) (October 2021)
  • Final Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037-80-3) Also Known As “GenX Chemicals” (pdf) (October 2021)
  • EPA Response to Public Comments on Draft Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037-80-3) Also Known as “GenX Chemicals” (Docket ID No. EPA‐HQ‐OW‐2018‐0614) (pdf) (October 2021)
  • EPA Response to Additional Focused External Peer Review of Draft Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (GenX Chemicals) (pdf) (October 2021)

Previously released public draft assessment materials from November 2018 include:

  • Draft Toxicity Assessment for GenX Chemicals (pdf) (November 2018)
  • Technical Fact Sheet: Draft Toxicity Assessments for GenX Chemicals (pdf) (December 2018)
  • Federal Register Notice: Request for Public Review and Comment: Draft Human Health Toxicity Assessments for Hexafluoropropylene Oxide Dimer Acid and its Ammonium Salt (GenX Chemicals)(November 2018)
  • Draft Toxicity Assessment: Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037-80-3) Also Known as “GenX Chemicals” (pdf) (November 2018)
  • Response to External Peer Review Comments on the Draft Human Health Toxicity Values for Hexafluoropropylene Oxide (HFPO) Dimer Acid and Its Ammonium Salt (CASRN 13252-13-6 and CASRN 62037- 80-3) Also Known as “GenX Chemicals" (pdf) (November 2018)
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Last updated on January 13, 2022
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