Where It Comes From
Past use in aqueous film‑forming foams (AFFF), metal plating mist suppressants, and stain/water‑resistant treatments; releases from manufacturing sites and firefighting training areas [1][2].
How You Are Exposed
Drinking contaminated water; eating fish/wildlife; indoor dust; and certain jobs (firefighting, metal plating, PFAS manufacturing) [1].
Why It Matters
PFOS can raise cholesterol, change liver enzymes, reduce vaccine response in children, and is possibly carcinogenic to humans. EPA now has a 4 ppt drinking‑water standard for PFOS [1][2][3][4].
Who Is at Risk
People using contaminated private wells; workers handling AFFF or plating baths; pregnant people and infants (PFOS crosses the placenta and is found in breast milk); communities near airports/bases or PFAS facilities [1][2].
How to Lower Your Exposure
Check local water results; if PFOS is detected, use certified filters (reverse osmosis or activated carbon), test private wells, follow fish advisories, reduce dust with wet cleaning, and use workplace PPE and hygiene [1][2].
References
- [1]ATSDR. ToxFAQs for Perfluoroalkyls (PFAS). 2021. https://www.atsdr.cdc.gov/toxfaqs/tfacts200.pdf
- [2]U.S. EPA. National Primary Drinking Water Regulation for PFAS (Final Rule). 2024. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas
- [3]IARC. Press Release 264: IARC classifies PFOA as carcinogenic and PFOS as possibly carcinogenic to humans. 2023. https://www.iarc.who.int
- [4]NTP. Immunotoxicity Associated with Exposure to PFOA or PFOS (Systematic Review). 2016. https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/completed/pfoa/index.html