The Environmental Protection Agency on Tuesday proposed the first federal limits on harmful “forever chemicals” in drinking water, a long-awaited protection the agency said will save thousands of lives and prevent serious illnesses, including cancer.

The plan would limit toxic PFAS chemicals to the lowest level that tests can detect. PFAS, or per- and polyfluorinated substances, are a group of compounds that are widespread, dangerous and expensive to remove from water. They don’t degrade in the environment and are linked to a broad range of health issues, including low birthweight and kidney cancer.