A soldier prepares CS tear gas to burn during a simulated chemical weapons attack in the gas chamber on Camp Atterbury, Ind., June 22, 2012. The soldiers were exposed to the chemical agent to familiarize them with the substance and teach them how to properly wear their gas masks. A soldier prepares CS tear gas to burn during a simulated chemical weapons attack in the gas chamber on Camp Atterbury, Ind., June 22, 2012. The soldiers were exposed to the chemical agent to familiarize them with the substance and teach them how to properly wear their gas masks. SHARE: Download: Full Size (1.42 MB) Tags: Photo Essays Credit: VIRIN: 528885-G-NAZ08-177.jpg Photo Gallery