ELLSWORTH AIR FORCE BASE, S.D. -- Airman 1st Class Julie Kemps, 28th Medical Operations Squadron flight medicine technician, breathes through her gas mask during a phase II operational readiness exercise, July 21. Airmen wear the gas mask during the phase II ORE as a means to improve their skills, should an actual attack occur while deployed. (U.S. Air Force photo/Airman 1st Class Anthony Sanchelli)