U.S. Marine Corps Base Camp Pendleton Fire Department firefighters don their individual Nuclear, Biological, Chemical suits during Exercise Semper Durus at Camp Pendleton, Calif., June 15, 2015. Exercise Semper Durus is a regional command exercise comprised of field training scenarios designed to improve regional command and control, enhance interagency coordination, and improve installation capabilities to respond to, and recover from, a crisis event. Semper Durus also provides a scenario-based opportunity to validate the installation mission assurance all-hazard plan. (U.S. Marine Corps photo by Cpl. Ismael E. Ortega, MCIWEST-MCB CamPen Combat/Released)