Airmen from the 301st Fighter Wing Mission Support Group prepare their gas masks to fit properly with an air-tight seal during an Ability to Survive and Operate (ATSO) training Saturday, Aug. 5, 2017 at Naval Air Station Fort Worth Joint Reserve Base, Texas. Annual exercises hone Airmen’s skills to continue executing the mission in austere conditions. (U.S. Air Force photo/ Tech. Sgt. Jeremy Roman)