171104-N-PC620-0099 ATLANTIC OCEAN (Nov. 4, 2017) Airman Melanie Salcedo, right, breathes as Aviation Ordnanceman 1st Class Joshua Collins uses a smoke tube pump to test for a proper fit during a respirator fit test in the hangar bay of the amphibious assault ship USS Iwo Jima (LHD 7). Iwo Jima, components of the Iwo Jima Amphibious Ready Group and the 26th Marine Expeditionary Unit are conducting a Combined Composite Training Unit Exercise that is the culmination of training for the Navy-Marine Corps team and will certify them for deployment. (U.S. Navy photo by Mass Communication Specialist Seaman Michael H. Lehman/Released)