Forever Chemicals (PFAS) Explained: A Simple Guide
What PFAS are, where they come from, and why they are called forever chemicals.
What makes them "forever"
PFAS (per- and polyfluoroalkyl substances) contain carbon-fluorine bonds, among the strongest in organic chemistry. These bonds do not break down in water, soil, or the human body. A PFAS molecule released into the environment today will still be there in decades or centuries. There are over 12,000 known PFAS compounds.
Where they are used
Non-stick cookware (Teflon), waterproof clothing (Gore-Tex), food packaging (microwave popcorn bags, fast food wrappers), firefighting foam (AFFF), stain-resistant fabrics (Scotchgard), and hundreds of industrial applications. They enter water through manufacturing discharge, firefighting foam use at military bases and airports, and landfill leachate.
The 2024 EPA rule
In April 2024, the EPA set maximum contaminant levels for six PFAS compounds. PFOS and PFOA limits are 4 parts per trillion (ppt), among the lowest MCLs ever set. Utilities have until 2029 to comply. Check your city's PFAS levels and see our PFAS filter guide.