PFAS (per- and polyfluoroalkyl substances) are a family of thousands of synthetic chemicals prized for resisting grease, water, and heat. In food, they show up in some grease-resistant wrappers, microwave popcorn bags, and fast-food packaging, and can migrate into the food. They're nicknamed forever chemicals because their bonds resist breaking down, so they accumulate in water, soil, and human blood.
Higher PFAS exposure has been linked in studies to raised cholesterol, reduced vaccine response in children, and certain cancers — which is why the U.S. EPA set its first enforceable limits for PFAS in drinking water in 2024. To reduce exposure: limit greasy fast food in treated packaging, don't microwave in coated bags, and use a filter certified to reduce PFAS if your water is affected.