PFAS (forever chemicals)

PFAS ('per- and polyfluoroalkyl substances') are a class of thousands of synthetic chemicals with extremely stable carbon-fluorine bonds. That stability makes them persist in the environment, and the long-chain ones (like PFOA and PFOS) linger in human blood for several years. You are exposed through contaminated drinking water, food packaging, non-stick cookware, and certain jobs. PFAS have been found in blood and tissue worldwide, even in remote Arctic populations. Studies link PFAS exposure to weaker antibody responses to vaccines, abnormal cholesterol, thyroid disruption, lower birthweight, and higher risk of kidney and testicular cancer. The proposed mechanisms involve activating PPAR-alpha and interfering with nuclear receptors. Regulation is in flux. In April 2024, the US EPA set its first enforceable drinking-water limits for PFOA and PFOS, at 4 parts per trillion. In May 2025, the EPA kept those 4 ppt limits but said it intends to rescind the limits for several other PFAS (PFHxS, PFNA, GenX/HFPO-DA, and the Hazard Index mixture limit), and extended the PFOA/PFOS compliance deadlines by two years. As of May 2026, that rollback is still in rulemaking. Meanwhile, the EU is pursuing a parallel restriction under REACH that covers entire PFAS groups.

Last reviewed: June 22, 2026

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