The Biden administration on Friday finalized a new rule designating two widely used “forever chemicals” as hazardous substances under federal law, an effort to keep polluters on the hook for any contamination caused by the toxic, cancer-linked chemicals.

Per- and polyfluoroalkyl substances are widely used in the U.S. to make everything from nonstick cookware and personal care products to children’s toys. But exposure to the toxic substances is linked to a litany of health problems, including reproductive problems, developmental delays for children, certain types of cancers, and liver and heart problems in adults.