U.S. Marines assigned to Chemical, Biological, Radiological

U.S. Marines assigned to Chemical, Biological, Radiological and Nuclear (CBRN) Defense units across I Marine Expeditionary Force participate in a live-fire range utilizing Mission-Oriented Protective Posture (MOPP) level IV, during a CBRN Defense challenge on Marine Corps Air Station Miramar, San Diego, Calif., April 28, 2015. The training sustained the Marines' proficiency in conducting live-fire operations while protecting themselves against the threat of CBRN contamination. (U.S. Marine Corps photo by Cpl. Laura Y. Raga/ RELEASED)