Perfluoroalkyl and polyfluoroalkyl substances are increasingly found in water supplies throughout the United States.
The class of chemicals, known as PFAS, includes more than 4,000 individual chemicals with similar properties. PFAS don't readily break down once they're in the environment or human bodies, so they can accumulate in animal and human tissues.
The compounds, used in products such as stain- and water-resistant clothing, nonstick pots and pans, firefighting foam, carpets and furniture, are linked to health effects including testicular and kidney cancers, decreased birth weights, thyroid disease, decreased sperm quality, high cholesterol, pregnancy-induced hypertension, asthma and ulcerative colitis.
In Pennsylvania, there are 20 known contaminated sites, including at least two in Southwestern Pennsylvania.
The stories below are part of an ongoing collaboration between Environmental Health News and PublicSource tracking the impacts of PFAS contamination in Pennsylvania and efforts to clean up the chemicals.