ELLSWORTH AIR FORCE BASE, S.D. -- (Right) Airmen 1st Class David Jack and Matthew Hung, 28th Civil Engineer Squadron emergency management journeymen, participate in an emergency management exercise, June 3. The exercise is performed to maintain skills needed in chemical, biological, radiological and nuclear detection and decontamination operations as well as emergency management command and control for real world incidents. (U.S. Air Force photo/Airman 1st Class Corey Hook)