Airman 1st Class Jessica Gluth, 28th Civil Engineer Squadron emergency management technician, removes her gas mask during an emergency response training simulation on Ellsworth Air Force Base, S.D., May 23, 2013. Airmen participating in the exercise donned Level A hazardous material suits to protect themselves while attempting to stop, control and identify a simulated fluid leak from a rail car accident. (U.S. Air Force photo by Airman 1st Class Ashley J. Thum/Released)