Airmen walk out of a gas mask confidence building after they were able to understand the protection provided by a mask when exposed to a mild chemical agent during Ability to Survive and Operate training at Sheppard Air Force Base, Texas, June 27, 2018. The Airmen entered the structure with their gas masks on, but later removed them to experience the sensation of not have the protection of the mask and how a chemical agent could affect them. (U.S. Air Force photo by John Ingle)