The explosion occurred Monday at 10 p.m. PDT (1 a.m. EDT Tuesday) during a Marine training exercise at the Hawthorne Army Depot in western Nevada, said facility manager Russ Collier. 

The Marines were from Camp Lejeune, North Carolina, a spokeswoman said. 

Victims were airlifted to Renown Regional Medical Center with injuries that included penetration trauma, fractures and vascular injuries, said Stacy Kendall, a spokeswoman for the medical center. The status of the injured was unclear.