A new study confirms the presence of a gnarly group of substances in tap water in 24 states.

Remember those disturbingly ubiquitous chemicals that the Environmental Protection Agency can’t bring itself to ban from our drinking water? Per- and polyfluoroalkyl (PFAS) are man-made substances that were once prized for their ability to make surfaces resist heat, oil, stains, grease, and water. Until the United States started to phase them out in 2006, PFAS were used in everything from microwave popcorn bags to fast-food wrappers to water-repellent clothing. One of them, PFOA, made famous by its use in Teflon, has been linked to high cholesterol, ulcerative colitis, thyroid conditions, and testicular and kidney cancers.

For a newly released study, the agency’s own scientists, in tandem with US Geological Survey peers, took samples from 25 drinking water treatment plants (in confidential locations across 24 states) and tested them for PFAS. The result: All of the samples tested positive for the chemicals, though just one exceeded the EPA’s voluntary “health advisory” of 70 parts per trillion for PFOA and PFOS, the most-studied of the chemicals.