Per- and Polyflouroalkyl substances (PFAS) describes a class of man-made chemicals that include PFOS, PFOA, GenX, and many others. More than 4,700 different types of PFAS have been identified and this number continues to grow as more chemicals are developed by industries. The most common uses for these chemicals are in non-stick cookware, stain and water-resistant fabrics, firefighting foam, and a host of other industrial products. Because of the variety of chemicals, research has been difficult to conduct, but efforts have uncovered links to harmful health effects. Some of these effects include  low infant birth weight, elevated cholesterol, abnormal thyroid hormone levels, liver inflammation, weakening of the immune system, and kidney cancer.

It is estimated that 16 million people in the U.S. get their water from a source with PFAS levels that exceed the suggested limit of 70 parts per trillion set by the EPA. PFAS have been shown to persist in the environment and bioaccumulate in living organisms, suggesting that contamination will be a long-term issue. Because PFAS are commonly used at industrial sites and landfills, these chemicals tend to disproportionately harm minority and low income communities.