DuPont and 3M, which was manufacturing PFAS and using one in Scotchgard, began studying the potential health effects of their formulations in part as an occupational-safety measure. Initially, scientists assumed that because the first compounds were so stable and resistant to change — “inert,” in chemistry parlance — it would be impossible for them to interact with biological systems. The companies’ in-house experiments, along with other studies, quickly overturned that notion. By 1965, DuPont had indication that PFAS increased the liver and kidney weight of rats.
In the late ’70s and early ’80s, the companies were seeing alarming signals in their animal studies — in one study, monkeys exposed to extreme levels of PFAS died — and among their employees. In 1979, DuPont observed that workers who had contact with the chemicals appeared to have higher rates of abnormal liver function. In 1981, 3M researchers alerted their DuPont colleagues that pregnant rats exposed to PFAS had pups with eye irregularities; that year, an employee at a Teflon plant gave birth to a child with one nostril, a keyhole pupil and a serrated eyelid. In 1984, DuPont detected PFAS in the tap water of three communities near its West Virginia factory.
In 1998, 3M told the Environmental Protection Agency that it had tried and failed to identify members of the public without PFOS — a type of PFAS it was producing — in their blood. Two years later the company, which was the only U.S. maker of PFOS, announced that it planned to phase out its manufacture of the chemical. (3M had occasionally shared data with the E.P.A. in the 1980s; DuPont’s human and animal research wouldn’t become known until 2001, after a lawsuit forced the company to turn over documentation related to PFOA to opposing counsel, and he alerted the E.P.A. and other agencies.) In 1999, the National Health and Nutrition Examination Survey, an ongoing project run by the Centers for Disease Control and Prevention to track the health of the U.S. population, began testing for PFAS in participants and would confirm 3M’s observations: The chemicals were present in virtually everyone.
This revelation was met with a collective shrug by federal health officials and policymakers. More than two decades later, in fact, PFAS production remains largely unregulated. There are more than 12,000 variations of the chemicals, very few of which have been investigated for their potential health effects. Using data from the E.P.A. and other government agencies, the Environmental Working Group, a nonprofit research and advocacy organization, has mapped more than 41,000 places in the United States and its territories where PFAS are potentially being made, used or released: military sites, airports, landfills, wastewater-treatment plants, oil refineries. This year, the group announced that more than 2,800 domestic locations are confirmed to be contaminated with the chemicals.
PFAS can be removed from tap water, but according to the E.P.A., tap water typically accounts for only about 20 percent of a person’s overall exposure to the chemicals; we also eat them, inhale them and rub them on our skin. Testing by government agencies and watchdog groups have found PFAS in carpets, furniture, nail polish, shampoo, mascara, nonstick cookware, dental floss, raincoats, fast-food wrappers, pizza boxes, microwave popcorn bags, yoga pants, sneakers, sanitary pads, tampons, menstrual cups, bedding, upholstery, children’s pajamas, paint, vinyl flooring and artificial turf. They’re in the protective equipment used by firefighters and medical personnel. They’re in an especially effective foam for putting out fuel-based flames. They’re in dust and the household cleaning products you might use to get rid of it. They are in flamingos in the Caribbean and plovers in South Korea. They are in alligators. They are in Antarctic snow. In Europe, they’ve been discovered in organic eggs; in the United States certain states have found them in produce and meat. Last year, a study of PFAS in freshwater fish in the United States revealed median levels so elevated that eating a single serving could be equivalent to drinking PFAS-contaminated water for a month. In June, the U.S. Geological Survey reported that it had tested private wells and public water supplies and found at least one PFAS in 45 percent of the nation’s tap water.