Airman 1st Class Alfredo Guzman, 509th Civil Engineer Squadron journeyman, assists Airman 1st Class Brandon Stone, 509th CES apprentice, with donning a FireHawk M7 mask at Whiteman Air Force Base, Mo., May 22, 2013. The mask is a self-contained breathing apparatus used to prevent any inhalations from chemicals or biological hazards. (U.S. Air Force photo by Airman 1st Class Keenan Berry/Released)