Airman 1st Class Roderick Williams, a bioenvironmental engineering journeyman assigned to the 28th Medical Operations Squadron, dons a chemical protection suit during an exercise at Ellsworth Air Force Base, S.D., June 7, 2017. During the exercise, the bioenvironmental engineering flight responded to a simulated chemical, biological, radiological, and nuclear environmental (CBRNE) threat to determine if it was an immediate threat to the installation. (U.S. Air Force photo by Staff Sgt. Hailey Staker)