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CAS 307-35-7

Perfluorooctylsulfonyl fluoride

Perfluorooctylsulfonyl fluoride (POSF) is an industrial PFAS used to make PFOS and related stain- and water-repellent chemicals. POSF-based substances can transform into PFOS, a highly persistent pollutant that builds up in people and the environment [1][2].

Where It Comes From

Production of PFOS/POSF-based repellents and older firefighting foams; releases from manufacturing, AFFF use, and contaminated sites [1][2].

How You Are Exposed

Mostly via PFOS in drinking water, food, and household dust; higher near PFAS facilities, airports, or firefighting sites; some jobs involve air/skin contact [1][2].

Why It Matters

PFOS exposure is linked to increased cholesterol, reduced vaccine response, liver and developmental effects; PFOS is classified as possibly carcinogenic (IARC Group 2B) [1][3][4].

Who Is at Risk

Infants, children, and pregnant people; workers making/using PFAS; communities with contaminated water or frequent AFFF use [1][2].

How to Lower Your Exposure

Use PFAS-reducing water filters; follow local water and fish advisories; damp-dust and clean regularly; avoid or carefully handle older AFFF/stain-resistant products; follow workplace protections [1][2].

References

  1. [1]ATSDR. Toxicological Profile for Perfluoroalkyls (PFAS). Agency for Toxic Substances and Disease Registry, 2021.
  2. [2]EPA. Our Current Understanding of the Human Health and Environmental Risks of PFAS. U.S. Environmental Protection Agency.
  3. [3]IARC. Perfluorooctane sulfonic acid (PFOS): possibly carcinogenic to humans (Group 2B). IARC Monographs Vol. 134, 2023.
  4. [4]NTP. Monograph on Immunotoxicity Associated with Exposure to PFOA and PFOS. National Toxicology Program, 2016.

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