U.S. Air Force Airman 1st Class Derek Guess, 633rd Aerospace Medicine Squadron public health technician, stores samples of simulated-contaminated food during a terrorist use of chemical, biological, radiological, nuclear and high-yield explosive exercise, July 26, 2012, at Langley Air Force Base, Va. Guess participated as a member of the sampling team, working jointly with 633rd Air Base Wing observers and inspectors throughout the exercise. (U.S. Air Force photo by Senior Airman Stephanie Rubi/Released)