Some chemicals in the environment break down slowly, and as a result they become chemicals with consequences. There is a group of such persistent chemicals, perfluoroalky substances and polyfluoroalkyl substances or PFAS for short. They have a strong bond between fluorine and a carbon
News came out that the EPA (Environmental Protective Agency) did multiple measurements in drinking water samples throughout the US. This happened between 2012 and now and they found cancer producing chromium-6 in drinking water. History of cancer producing chromium-6 in drinking water