U.S. Army Sgt. 1st Class Freddie Acevedo of the 673rd Quartermaster Company briefs his soldiers before they begin a biohazard decontamination exercise at Northwest Community Hospital, Arlington Heights, Ill., June 10, 2011. Known as "Red Dragon," the mock decontamination exercise gives military units and civilian emergency services a chance to practice and prepare for natural or other types of disasters.