A U.S. Marines attached to A Company, 1st Battalion, 3rd Marine Regiment, "The Lava Dogs" holds security for UH-60 Black Hawks inserting Marines for an assault on an enemy village at Lava Viper aboard Pohakuloa Training Area, Hi., Jun. 10, 2015. While conducting the assault, A Company must also manuever through chlorobenzalmalononitrile (CS) gas making them wear gas mask to proceed with their mission. (U.S. Marine Corps photo by Cpl. Ricky S. Gomez/Released)