Airman 1st Class Sean Berger, second from right, instructs airmen on the proper procedures to inspect a gas mask during chemical, biological, radiological, and nuclear defense training held at the North Carolina Air National Guard Base, Charlotte Douglas International Airport, N.C., Jan. 8, 2018. Berger is assigned to the 145th Civil Engineer Squadron. Air Force photo by Tech. Sgt. Julianne Showalter