U.S. Air Force Tech Sgt. Jason Smith, 633rd Aerospace Medicine Squadron Bio-environmental engineer, conducts a respirator protection briefing for members of the 633rd Force Support Squadron search-and-recovery team during a major accident response exercise at Langley Air Force Base, Va., Oct. 19, 2012. The exercise was held to assess how well members of the base rescue casualties during a major accident. (U.S. Air Force photo by Staff Sgt. Ashley Hawkins/Released)