The story began in 1951, when DuPont started purchasing PFOA (which the company refers to as C8) from 3M for use in the manufacturing of Teflon. 3M invented PFOA just four years earlier; it was used to keep coatings like Teflon from clumping during production. Though PFOA was not classified by the government as a hazardous substance, 3M sent DuPont recommendations on how to dispose of it. It was to be incinerated or sent to chemical-waste facilities. DuPont’s own instructions specified that it was not to be flushed into surface water or sewers. But over the decades that followed, DuPont pumped hundreds of thousands of pounds of PFOA powder through the outfall pipes of the Parkersburg facility into the Ohio River. The company dumped 7,100 tons of PFOA-laced sludge into ‘‘digestion ponds’’: open, unlined pits on the Washington Works property, from which the chemical could seep straight into the ground. PFOA entered the local water table, which supplied drinking water to the communities of Parkersburg, Vienna, Little Hocking and Lubeck — more than 100,000 people in all.
Bilott learned from the documents that 3M and DuPont had been conducting secret medical studies on PFOA for more than four decades. In 1961, DuPont researchers found that the chemical could increase the size of the liver in rats and rabbits. A year later, they replicated these results in studies with dogs. PFOA’s peculiar chemical structure made it uncannily resistant to degradation. It also bound to plasma proteins in the blood, circulating through each organ in the body. In the 1970s, DuPont discovered that there were high concentrations of PFOA in the blood of factory workers at Washington Works. They did not tell the E.P.A. at the time. In 1981, 3M — which continued to serve as the supplier of PFOA to DuPont and other corporations — found that ingestion of the substance caused birth defects in rats. After 3M shared this information, DuPont tested the children of pregnant employees in their Teflon division. Of seven births, two had eye defects. DuPont did not make this information public.
In 1984, DuPont became aware that dust vented from factory chimneys settled well beyond the property line and, more disturbing, that PFOA was present in the local water supply. DuPont declined to disclose this finding. In 1991, DuPont scientists determined an internal safety limit for PFOA concentration in drinking water: one part per billion. The same year, DuPont found that water in one local district contained PFOA levels at three times that figure. Despite internal debate, it declined to make the information public.
(In a statement, DuPont claimed that it did volunteer health information about PFOA to the E.P.A. during those decades. When asked for evidence, it forwarded two letters written to West Virginian government agencies from 1982 and 1992, both of which cited internal studies that called into question links between PFOA exposure and human health problems.)
By the ’90s, Bilott discovered, DuPont understood that PFOA caused cancerous testicular, pancreatic and liver tumors in lab animals. One laboratory study suggested possible DNA damage from PFOA exposure, and a study of workers linked exposure with prostate cancer. DuPont at last hastened to develop an alternative to PFOA. An interoffice memo sent in 1993 announced that ‘‘for the first time, we have a viable candidate’’ that appeared to be less toxic and stayed in the body for a much shorter duration of time. Discussions were held at DuPont’s corporate headquarters to discuss switching to the new compound. DuPont decided against it. The risk was too great: Products manufactured with PFOA were an important part of DuPont’s business, worth $1 billion in annual profit.