Tech. Sgt. Benjamin Thomas, 28th Security Forces Squadron defender, briefs Tech. Sgt. Roderick Marquez and Airman Jacquob Fitzgerald, 28th Civil Engineer Squadron firefighters, on a simulated accident situation during a major accident response exercise at Ellsworth Air Force Base, S.D., April 22, 2015. While being evaluated, the exercise provided a means for base first responders to apply their training tailored to specific circumstances and conditions. (U.S. Air Force photo by Senior Airman Anania Tekurio/Released)