Staff Sgt. Christopher Moen, the chemical, biological, radiological and nuclear (CBRN) staff non-commissioned officer-in-charge ensures each Marines gas mask is in working order before training begins during Marine Aircraft Group 13 (MAG -13) Headquarters bi-annual CBRN certification class, held at the gas chamber aboard the training area at MCAS Yuma, Ariz., Thursday, Jan. 28, 2016. - Staff Sgt. Christopher Moen, the chemical, biological, radiological and nuclear (CBRN) staff non-commissioned officer-in-charge ensures each Marines gas mask is in working order before training begins during Marine Aircraft Group 13 (MAG -13) Headquarters bi-annual CBRN certification class, held at the gas chamber aboard the training area at MCAS Yuma, Ariz., Thursday, Jan. 28, 2016.