Attorney Robert Bilott discovered that DuPont had known since the 1960s that PFOA (used to make Teflon) was toxic and contaminating water supplies near its Parkersburg, West Virginia plant. Internal documents showed DuPont found the chemical in workers' blood, linked it to birth defects, and detected it in public water — yet continued production and hid the data. A class-action settlement funded a health study linking PFOA to six diseases including kidney cancer.