Perfluoroalkyl and polyfluoroalkyl substances, known as PFAS, are man-made chemicals whose toxicity has led them to being the impetus for tens of thousands of lawsuits across the country. The typical defendant? The manufacturers and suppliers of PFAS, as well as downstream companies that use these chemicals either in their products (carpet manufacturers and the makers of firefighter turnout gear, for instance) or in their operations (like airports and military bases that use ubiquitous PFAS-containing fire suppressants called aqueous film forming foam (AFFF)).