Per- and polyfluoroalkyl substances (PFAS) are a family of approximately 4,700 synthetic compounds that are used in everything from housewares to fire-fighting foam. PFAS persist in the environment and bioaccumulate, and studies have found that 97 percent of people have PFAS in their blood .
Used to make products resistant to water, heat, and stains, PFAS are used in industrial applications and found in consumer goods such as clothing, food packaging, cookware, cosmetics, and carpet as well as a fire-fighting foam known as aqueous film-forming foam. People are exposed to PFAS by consuming contaminated water and food, breathing in dust with PFAS, and contact with consumer products that contain PFAS.
Evidence of harmful health effects led to the phasing out of two of the most researched chemicals, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in the United States through the US EPA PFOA Stewardship Program . But PFOA and PFOS had already made their way into drinking water, surface water, and groundwater.
Scientific studies show a number of these compounds are linked to human health issues . Some manufacturers in the United States replaced the phased-out chemicals (PFOA and PFOS) with shorter chain PFAS such as GenX, and evidence is emerging that these shorter chain PFAS also persist in the environment and bioaccumulate in people with possible health effects , , , . The majority of PFAS now in use have not been studied .
What is the evidence of health effects?
PFOA, one of the most well-studied PFAS, has been linked to kidney and testicular cancer , , , decreased antibody responses to vaccines , liver damage, increased cholesterol levels , increased risk of thyroid disease , increased risk of decreased fertility, decreases in birth weight , and increased risk of pregnancy-induced hypertension and preeclampsia , .
Recognizing the lack of evidence, federal agencies are funding and conducting research to better understand exposure to additional compounds. The U.S. EPA, Department of Defense, Federal Drug Administration, US Department of Agriculture, National Institutes of Health, the Centers for Disease Control and Prevention (CDC) and Agency for Toxic Substances and Disease Registry (ATSDR) are funding and conducting research on health effects from exposure to PFAS, and remediation and treatment strategies for contaminated water and soil.
How are PFAS regulated in drinking water?
There are not yet any federally enforceable standards for PFAS in drinking water in the United States. The U.S. Environmental Protection Agency (EPA) established a health advisory level for two PFAS - PFOA and PFOS -- at a combined total of 70 parts per trillion in drinking water, but that is not an enforceable regulation. In February 2019, the U.S. EPA issued an Action Plan  that outlines next steps for the agency to address PFAS and human health impacts at the federal level.
In the absence of a federal drinking water standard, numerous U.S. states including California, Massachusetts, Minnesota, New Jersey, New Hampshire, North Carolina, and Vermont have adopted or proposed drinking water standards for PFOS, PFOA, and other PFAS (e.g. notification levels, health based guidance or maximum contaminant levels). Additional states including Connecticut, Michigan, New York, and Wisconsin are considering or are in the process of proposing standards for regulating PFAS levels in drinking water to protect human health.
U.S. Agency for Toxic Substances and Disease Registry, Toxicological Profile for Perfluoroalkyls
U.S. Environmental Protection Agency, PFAS Action Plan
Interstate Technology Regulatory Council (ITRC), PFAS Fact Sheets