Airman 1st Class Maxwell Dean, a material management apprentice with the 1st Special Operations Logistics Readiness Squadron, oversees a gas mask seal test at Hurlburt Field, Fla., July 7, 2016. A Joint Service Mask Leakage tester monitors aerosol vapor under a gas mask shroud to check masks for leaks and blocks. (U.S. Air Force photo by Senior Airman Andrea Posey)