U.S. Air Force Airman 1st Class Danielle, 30th Intelligence Squadron imagery analyst, dons a gas mask during a fit-test at Langley Air Force Base, Va., Aug. 18, 2015. The test is a requirement of all Service members prior to deployment. (U.S. Air Force photo by Senior Airman Kimberly Nagle/Released)(Last name withheld for operational security purposes)