Firefighters from the 802nd Civil Engineer Squadron carry a patient to safety after a simulated chemical attack during an anti-terrorism exercise at Lackland March 30. The three-day exercise simulated the release of a nerve agent and involved units at Lackland, Randolph AFB and Fort Sam Houston. (U.S. Air Force Photo/Robbin Cresswell)

Senior Airman Brandon Ruebsamen, 559th Aerospace Medicine Squadron, uses a multi-gas meter to detect changes in the atmosphere, such as reduced oxygen levels and possible presence ofchemicals, during an anti-terrorism exercise March 30. The three-day exercise simulated the release of a nerve agent and involved units at Lackland, Randolph AFB and Fort Sam Houston. (U.S. Air Force photo/Robbin Cresswell)

Master Sgt. Tammy Freeman (center) briefs exercise participants after a simulated chemical attack during an anti-terrorism exercise at Lackland Air Force Base on March 30. The three-day exercise simulated the release of a nerve agent and involved units at Lackland, Randolph AFB and Ft. Sam Houston, Texas. Sergeant Freeman is superintendent of the 59th Medical Wing Exercise Evaluation Team and Inspector General Office. (U.S. Air Force Photo/Staff Sgt. Josie Walck)