The Environmental Protection Agency is proposing that nine PFAS, also known as “forever chemicals,” be categorized as hazardous to human health. The EPA signed a proposal Wednesday that would deem the chemicals “hazardous constituents” under the Resource Conservation and Recovery Act. For the agency to consider a substance a hazardous constituent, it has to be toxic or cause cancer, genetic mutation or the malformations of an embryo. … PFAS have been called “forever chemicals” because they break down very slowly and can accumulate in people, animals and the environment. Last summer, a study by the U.S. Geological Survey found that the man-made chemicals are present in nearly half the country’s tap water supply.