U.S. Air Force Airman 1st Class Candace Carrico, 19th Civil Engineer Squadron emergency management journeyman, instructs a Chemical, Biological, Radiological and Nuclear Defense Class at Little Rock Air Force Base, Arkansas, Sept. 12, 2019. The CBRN Defense Class instructors added more information on radiological and nuclear devices to prepare Black Knights for the upcoming exercise. (U.S. Air Force photo by Senior Airman Kristine M. Gruwell)