U.S Marine Corps Recruit with Platoon 4046, O. Co.,

U.S Marine Corps Recruit with Platoon 4046, O. Co., 4th Battalion, Recruit Training Regiment, prepare to conduct chemical, biological, radiological, nuclear (CBRN) defense training near the gas chamber at Marine Corps Recruit Depot, Parris Island, S.C., Oct. 25, 2016. Training for CBRN defense is an event that recruits must complete in order to become United States Marines. (U.S. Marine Corps photo by Lance Cpl. Sarah Stegall/Released)