This story was originally published by  Grist . Sign up for Grist’s weekly newsletter  here . The Trump administration has  announced  what it is calling “a major step forward” in the fight against a class of toxic chemicals called PFAS, or per- and polyfluoroalkyl substances. Extended exposure to PFAS, often referred to as “forever chemicals” because they can persist indefinitely in the environment,  has been linked  to various cancers, autoimmune diseases, and other harms. Last week,