A member of the U.S. Air Force 51st Security Forces Squadron moves up a hillside as he conducts a search through an industrial facility on Jan. 7, 1999, as part of combat employment readiness exercise Beverly Midnight 99-1, at Osan Air Base, Republic of Korea. The exercise is designed to test people's ability to carry out their wartime tasking, air base ground defense, and ability to recover after attacks. During the exercise, personnel quickly become accustomed to working and resting while wearing the Ground Crew Ensemble and its MCU-2P chemical/biological protective mask to protect themselves from chemical warfare agents.