** FILE ** Storage bunkers at the U.S. Army Depot in Hawthorne, Nev., are pictured in 2005. Seven Marines from a North Carolina unit were killed and several injured in a training accident at the depot, the Marine Corps said on Tuesday, March 19, 2013. The cause of the accident, which occurred shortly before 10 p.m. PST Monday, is under investigation, officials said in a statement from the 2nd Marine Expeditionary Force at Camp LeJeune, N.C. The Hawthorne Army Depot, which stores and disposes of ammunition, is made up of hundreds of buildings spread over more than 230 square miles. (AP Photo/Joe Cavaretta)

Photo by: JOE CAVARETTA

** FILE ** Storage bunkers at the U.S. Army Depot in Hawthorne, Nev., are pictured in 2005. Seven Marines from a North Carolina unit were killed and several injured in a training accident at the depot, the Marine Corps said on Tuesday, March 19, 2013. The cause of the accident, which occurred shortly before 10 p.m. PST Monday, is under investigation, officials said in a statement from the 2nd Marine Expeditionary Force at Camp LeJeune, N.C. The Hawthorne Army Depot, which stores and disposes of ammunition, is made up of hundreds of buildings spread over more than 230 square miles. (AP Photo/Joe Cavaretta)