Members of Congress are calling on the Trump administration to release a suppressed federal report on the health effects of four perfluoroalkyl substances (PFASs) that taint drinking water in many areas across the U.S. In January, the Agency for Toxic Substances & Disease Registry (ATSDR), part of the Department of Health & Human Services, planned to publish a draft toxicological profile for perfluorooctanoic acid, perfluorononanoic acid, perfluorohexane sulfonic acid, and perfluorooctane sulfonic acid according to recently released emails. But EPA and the Department of Defense, which faces liability for cleaning up PFASs in groundwater near many military sites, intervened, calling the report a “potential public relations nightmare,” the emails say. ATSDR’s study suggests safe levels for these PFASs of between 12 parts per trillion and 516 ppt, the emails say. Such low concentrations would drive extensive and expensive cleanups for the military as well as for companies that made or used these chemicals and released them to the environment. EPA is holding a meeting with states about PFAS pollution from May 22–23, and some members of Congress are seeking release of ATSDR’s report before that event.