Airman 1st Class Alvaro Munarriz, 11th Civil Engineer Squadron firefighter, left, and Staff Sgt. Clinton Oliver, 11th CES crew chief, perform their initial sweep of the affected area during a Chemical, Biological, Radiological, Nuclear and Explosives training exercise at Joint Base Andrews, Md., April 28, 2016. The scenario simulated a disgruntled Airman that released ammonia on base to cause mass casualties in the contamination area. (U.S. Air Force photo by Senior Airman Dylan Nuckolls/Released)