A USA TODAY analysis of new EPA data shows local officials most frequently blame airports; utilities, such as sewage treatment plants; and military bases as likely sources of toxic “forever chemicals” in their drinking water. Thousands of public drinking water systems began sampling last year for PFAS, or per- and polyfluoroalkyl substances, in the Environmental Protection Agency’s largest-ever effort to monitor their spread across the country. As water utilities submit their results, the EPA also asks if they’re aware of any sources that may have polluted their drinking water. Most systems marked “No” or “Don’t know” in the records the EPA released this month, but about 730 checked off boxes next to a list of two dozen potential sources. …Military bases topped the list of potential sources among drinking water systems that detected PFAS above the EPA’s new limits, but USA TODAY found airports closely followed with 50 systems. These include Fresno, California; Newport News, Virginia; and Greensboro, North Carolina