170921-F-RU983-0319
U.S. Air Force Col. John Klein, the commanding officer of the 60th Air Mobility Wing, checks the respirators on his gas mask during a chemical, biological, radiological and nuclear defense survival skills training course on Travis Air Force Base, Calif., Sep. 21, 2017. CBRN defenses are protective measures taken in situations in which chemical, biological, radiological or nuclear warfare (including terrorism) hazards may be present. CBRN defense consists of CBRN passive protection, contamination avoidance and CBRN mitigation. (U.S. Air Force photo by Heide Couch)
170921-F-RU983-0319
U.S. Air Force Col. John Klein, the commanding officer of the 60th Air Mobility Wing, checks the respirators on his gas mask during a chemical, biological, radiological and nuclear defense survival skills training course on Travis Air Force Base, Calif., Sep. 21, 2017. CBRN defenses are protective measures taken in situations in which chemical, biological, radiological or nuclear warfare (including terrorism) hazards may be present. CBRN defense consists of CBRN passive protection, contamination avoidance and CBRN mitigation. (U.S. Air Force photo by Heide Couch)