A Soldier assigned to a Chemical, Biological, Radiological and Nuclear (CBRN) unit checks on a civilian "casualty" during a mass casualty decontamination operation at the Muscatatuck Urban Training Center in Butlerville, Indiana, April 23. The event is part of Army North's exercise Guardian Response 21, where Army Reserve and National Guard Soldiers, Engineers, CBRN specialists, as well as medical units are conducting Defense Support of Civil Authorities (DSCA) training at the multi-million dollar facility to help prepare them to respond to a CBRN catastrophe at home or abroad. (Official U.S. Army Reserve photo by Sgt. 1st Class Brent C. Powell)