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PFAS in Pennsylvania

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PFAS: What They Are

PFASFamilyTree.PNGPerfluoroalkyl and polyfluoroalkyl substances (PFAS) are man-made chemicals, are resistant to heat, water and oil, and persist in the environment and the human body.  PFAS are not found naturally in the environment. 

They have been used to make cookware, carpets, clothing, fabrics for furniture, paper packaging for food, and other materials that are resistant to water, grease, or stains. They are also used in firefighting foams and in a number of industrial processes.

History of PFAS in Pennsylvania

  • Pennsylvania state authorities first became aware of PFAS in 2013 when the U.S. Environmental Protection Agency (EPA) included perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in its Third Unregulated Contaminant Monitoring Rule (UCMR) for drinking water. The UCMR is a federal regulation that is updated every five years to include new contaminants that public water systems must monitor if they serve more than 10,000 customers. As a result, 175 of about 3,000 public water systems in Pennsylvania sampled for these compounds.
  • While PFAS chemicals have received much attention in both the scientific and regulatory communities, they are considered emerging contaminants because there is more to learn about these chemicals, the occurrence of these chemicals in the waters of the Commonwealth, how they impact the human body and what lasting, long-term health effects may be realized as a result of exposure. However, state agencies will continue to learn about, investigate, adapt and react to PFAS found in the environment and the impacts they may have on human health.
  • In January 2023, Pennsylvania’s PFAS MCL Rule was published in the Pennsylvania Bulletin, setting maximum contaminant levels (MCLs) for two PFAS – PFOA and PFOS – in drinking water in Pennsylvania. Learn more about Pennsylvania’s PFAS MCL Rule here.


PFOA and PFOS are widespread because they are persistent in the environment and do not readily break down when exposed to air, water, or sunlight. They can be found in air, soil, and water (both groundwater and surface water). PFOA and PFOS are also very persistent in the human body, and exposures to these chemicals are known to have a number of adverse effects in laboratory animals and humans. 

Exposure can occur when fish caught in waters contaminated with PFAS are eaten, foods packaged in PFAS coated materials are consumed, soil and dust polluted with PFAS are unintentionally ingested, or products made with PFAS chemicals are handled.

Scientists classify PFAS as emerging contaminants because the risks they pose to human health and the environment are not completely understood. While health impacts continue to undergo research studies, the research has concluded a probable link of PFAS to adverse health effects in laboratory animals and humans.
For more information on impacts: