Mask Mission Arizona Army National Guardsmen don protective masks during a simulated chemical attack at Florence Military Reservation, Ariz., Aug. 5, 2017. The soldiers, assigned to the 2220th Transportation Company, were conducting nuclear, biological and chemical warfare training. Army National Guard photo by Staff Sgt. Brian A. Barbour SHARE: Download: Full Size (2.23 MB) Credit: Staff Sgt. Brian Barbour VIRIN: 170805-Z-LW032-957Y.JPG Photo Gallery