U.S. Air Force Airman 1st Class Kevin Gillaspie, 633rd Civil Engineer Squadron post attack reconnaissance team member, reports the simulated contamination of a water drum during a Phase II Operational Readiness Exercise at Langley Air Force Base, Va., April 20, 2012. After a chemical attack, Airmen are required to sweep the area and search for any possible contamination. (U.S. Air Force photo by Senior Airman Jarad A. Denton/Released)