Player Embed Code: Download Embed Share DOD Official Testifies on the Impact of PFAS Exposure on Servicemembers Defense.gov March 11, 2020 | 01:35:37 Maureen Sullivan, deputy assistant secretary of defense for environment, Department of Defense, testifies at the House Appropriations subcommittee hearing concerning the impact of PFAS exposure on servicemembers, March 11, 2020. Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects.