Going Green Army Staff Sgt. Donald Zarate reacts to a simulated chemical attack during the Combined Best Squad Competition at Fort Knox, Ky., March 26, 2026. The event required competitors to properly retrieve, don and seal their protective masks within a 90-second standard. SHARE: Download: Full Size (1.46 MB) Tags: army, training Credit: Army Staff Sgt. Caroline Sauder VIRIN: 260326-A-WN944-1010M.JPG Photo Gallery