DuPont and its spin-off Chemours must further limit the perfluorinated chemical exposure of residents near a chemical manufacturing plant in Parkersburg, W.Va., under a revised deal with EPA. The facility formerly used perfluorooctanoic acid (PFOA) for decades. Through a recent update to a 2009 consent order with EPA, the companies must supply an alternate source of drinking water for residents when PFOA is measured at 70 parts per trillion in their piped-in drinking water. This lowers a threshold for such action that was set in 2009 of 400 ppt PFOA in drinking water and follows the agency’s 2016 lifetime health advisory limit for the chemical. The updated drinking water order comes amid ongoing litigation between the companies and residents of Parkersburg. The plaintiffs, with claims that tainted water has harmed their health, have brought 3,500 lawsuits against the chemical manufacturers. PFOA was once used in the manufacture of nonstick materials. Though U.S. manufacture of PFOA has stopped, the perfluorinated chemical is environmentally persistent and has been linked to disease in people.