PFAS (Forever Chemicals)
Per- and polyfluoroalkyl substances, a class of thousands of synthetic chemicals that don't break down in the environment, accumulate in the human body, and are linked to cancer, immune disorders, and developmental problems.
How It Works
PFAS have been manufactured since the 1940s and used in nonstick cookware (Teflon), food packaging, firefighting foam (AFFF), and waterproof clothing. They are called "forever chemicals" because their carbon-fluorine bonds are among the strongest in chemistry and don't break down naturally. PFAS are found in the drinking water of an estimated 200+ million Americans. In April 2024, the EPA set the first-ever national drinking water standards for six PFAS compounds, with maximum contaminant levels as low as 4 parts per trillion (ppt) for PFOA and PFOS. Water systems have until 2029 to comply. Testing for PFAS requires specialized analytical methods (EPA Method 533 or 537.1) not used in standard water quality monitoring.
Related Terms
- Maximum Contaminant Level (MCL), The highest level of a contaminant allowed in drinking water, set by the EPA and enforceable by law. Exceeding the MCL triggers a health-based violation.
- Health-Based Violation, The most serious type of drinking water violation, indicating that water quality has exceeded a maximum contaminant level or failed to meet a treatment requirement that directly protects health.
- PFOA (Perfluorooctanoic Acid), A specific PFAS compound formerly used in Teflon manufacturing, linked to kidney cancer, testicular cancer, thyroid disease, and high cholesterol. The EPA set a drinking water limit of 4 parts per trillion.
- PFOS (Perfluorooctane Sulfonic Acid), A PFAS compound historically used in Scotchgard, firefighting foam, and industrial applications, linked to cancer and immune system damage. EPA drinking water limit: 4 parts per trillion.
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About This Definition
This definition is part of the IsWaterSafe Drinking Water Safety Glossary, 22 terms explaining water contaminants, treatment methods, and safety standards. Written for homeowners, renters, journalists, and public health professionals.