Airmen from the 28th Civil Engineer Squadron and members of the South Dakota National Guard participate in a joint training exercise at Ellsworth Air Force Base, S.D., Jan. 10, 2017. The training scenario involved a simulated commander’s call at the base theater where attendees reported feelings of being ill, expressing they might have been exposed to some type of irritant. (U.S. Air Force photo by Airman 1st Class Denise M. Jenson)