Synthetic chemicals called PFASTrusted Source (per- and polyfluoroalkyl substances) are used in a variety of products, including cosmetics, cleaning productsTrusted Source, and nonstick cookware. Because many PFAS do not break down in landfills and can contaminate sources of drinking water for both humans and animals, they are considered harmful to the environmentTrusted Source. Additionally, exposure to PFAS has been linked to various health concerns.