Staff Sgt. Shawn Gallagher, 2nd Aerospace Medical Squadron Bioenvironmental Engineering craftsman, and Keith Lear, 2nd Bomb Wing Safety, review readings from an atmospheric monitoring meter taken by Staff Sgt. Shane Derrick and Airman 1st Class Brandon Curry, 2nd Civil Engineering Squadron electrical shop, on Barksdale Air Force Base, La., Nov 7. Routine testing of man-holes around the base ensure airborne hazards are or are not present in the confined spaces. (U.S. Air Force photo/Staff Sgt. Jason McCasland)(RELEASED)