On Wednesday, the Environmental Working Group released a shocking report about how toxic fluorinated chemicals known as PFAS have been found in the drinking water of dozens of U.S. cities, including major metropolitan areas such as Miami, Washington, D.C., and Philadelphia. We speak to the famed environmental lawyer Rob Bilott about his 20-year battle with DuPont over contaminated drinking water in West Virginia from toxic chemicals used to make Teflon. Bilott’s fight is portrayed in the new film “Dark Waters.”