U.S. Army Spc. Robert Nelson, a survey team member

U.S. Army Spc. Robert Nelson, a survey team member with the 43rd Civil Support Team, South Carolina Army National Guard, removes his chemical protective suit after conducting a site survey at the Savannah River Site during an Ardent Sentry exercise May 20, 2013, near Allen, S.C. Ardent Sentry is a North American Aerospace Defense Command and U.S. Northern Command (USNORTHCOM)-directed exercise focusing on defense support of civil authorities in response to simulated weather, security and disaster contingencies. While Ardent Sentry is primarily a command post exercise, several field training events were conducted at various locations within the USNORTHCOM area of responsibility. (U.S. Air National Guard photo by Tech. Sgt. Caycee Watson/Released)