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. DuPonts 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