U.S. Airmen from the 452nd Civil Engineer Squadron,

U.S. Airmen from the 452nd Civil Engineer Squadron, March Air Reserve Base, Calif., and 445th Civil Engineer Squadron, Wright-Patterson Air Force Base, Ohio, don their Mission-Oriented Protective Posture response level 4 (MOPP4). Service members are taking part in Operational Readiness Exercise, Crisis Challenge 09-12B, at the Combat Readiness Center, Gulfport, Miss., Sept. 21, 2012. Throughout the exercise, evaluators determine wing members’ abilities to mobilize, deploy, survive in combat environments and redeploy to home station. (U.S. Air Force photo by Tech. Sgt. Efren Lopez/Released)