Millions of Americans are drinking water containing toxic levels of industrial chemicals used to make common household products, according to a new study.

These substances had been common in everything from stain-resistant clothing and upholstery to food packaging and fire retardant. But, the chemicals have also been associated with cancer and chronic diseases such as obesity and high cholesterol, and have been phased out by U.S. manufacturers over safety concerns. Still, they persist in the environment.