Gas

Cpl. Anthony Blumenthal, 11th Marine Expeditionary Unit, lets tear gas into his XM50 joint-service general-purpose mask, part of chemical-biological-radiological-nuclear defense training here March 10. Blumenthal, 21, from Chicago, and approximately 100 unit members, drilled with the masks in a tear-gas filled chamber.
Photo by Gunnery Sgt. Scott Dunn