A recruit of Delta Company, 1st Recruit Training Battalion,

A recruit of Delta Company, 1st Recruit Training Battalion, breaks the seal on his gas mask while in the gas chamber Jan. 19, 2016, on Parris Island, S.C. By breaking the seals, recruits experience the gas' effects, which include temporary respiratory irritation, watery eyes and a burning sensation on the skin. Delta Company is scheduled to graduate March 11, 2016. Parris Island has been the site of Marine Corps recruit training since Nov. 1, 1915. Today, approximately 20,000 recruits come to Parris Island annually for the chance to become United States Marines by enduring 13 weeks of rigorous, transformative training. Parris Island is home to entry-level enlisted training for approximately 50 percent of male recruits and 100 percent of female recruits in the Marine Corps. (Photo by Sgt. Jennifer Schubert)