U.S Marine Corps Cpl. Aaron M. Henson, a combat correspondent with the Public Affairs Office, Headquarters and Headquarters Squadron, conducts a functions check on his M50 field protective mask during chemical, biological, radiological and nuclear (CBRN) defense training before entering the gas chamber at Marine Corps Air Station Iwakuni, Japan, Feb. 23, 2017.
The training ensures every Marine understands the risks associated with a toxic environment and familiarizes them with the M50 field protective mask. (U.S. Marine Corps photo by Lance Cpl. Jacob A. Farbo) Original public domain image from Flickr