According to sources, a multimillion dollar study on toxic chemicals in drinking water is facing delays due to a dispute within the Trump administration. The implications could affect a half dozen communities, where drinking water has been heavily contaminated with polyfluoroalkyl substances. The chemical is used in non-stick cookware, water-resistant clothing, food packaging, carpets and military firefighting foams. Scientists say delaying the study could limit the effectivness of the study.