U.S. Army Spc. James Hanson, 7th Battalion, 158th Aviation Regiment, lowers a casualty to be unloaded from a UH-60 Black Hawk during a medical evacuation mission as part of Exercise Vibrant Response at Camp Atterbury, Ind., Aug. 22, 2011. Vibrant Response is the largest chemical, biological, radiological and nuclear response exercise designed to prepare expeditionary units focused on responding to domestic CBRN incidents.