Selfridge Airmen ensure gas masks fit right Published Oct. 14, 2023 By Tech. Sgt. Chelsea E. FitzPatrick 127th Wing Public Affairs SELFRIDGE AIR NATIONAL GUARD BASE, Mich -- Tucked around the corner, at the end of the hallway, 127th Wing Airmen perform a little-known procedure that involves a candle and rotating their jaw. It could just save their life one day. When Air National Guard Airmen are issued a MCU-2/P gas mask as part of the gear that would allow them to survive a worst-case chemical weapons scenario, the first order of business is to have that mask checked out and have a fit test performed by a medical bioenvironmental technician. At Selfridge Air National Guard Base, one of the people who perform that task is Staff Sgt. Sean Kozara. “The mask is your first line of defense in a CBRN environment,” said Kozara, referring to a chemical, biological, radiological or nuclear weapon attack. During the fit test, technicians such as Kozara first lights a candle. The smoke from the candle contains particulates, which a sensing machine detects in the ambient air. The machine also senses the air inside the mask while it is being worn by an Airman. The machine then computes the difference between the two and determines if any of the outside air – which could contain a biological agent – is able to leak into the mask. If there is any leakage, the mask either needs to be re-adjusted or the Airman may need a different size. “Conducting the fit test also gives the Airman confidence to know that his or her gas mask will work as advertised,” Kozara said. During the test, the Airman wearing the masks rotates his or her head and jaw to ensure that the mask continues to fit properly during natural movements. Testing on this day was Airman 1st Class Eric Morgan, a power production specialist with the 127th Civil Engineer Squadron, who was recently issued a gas mask for the first time. “It fit great – no problems,” Morgan said. A gas mask fit test is required whenever an Airman is issued a new mask or if an Airman has a weight gain or loss of more than 10 percent from when the mask was initially issued.