U.S. Air Force Airman 1st Class Jerry Tondini, 633rd Security Forces Squadron installation entry controller, unfastens his boots during a phase I combined unit exercise at Langley Air Force Base, Va., Dec. 12, 2012. The CUE provided hands-on training to educate Airmen on the proper chemical contamination removal process. (U.S. Air Force photo by Senior Airman Racheal E. Watson/Released)