The four bomb removal technicians killed at Camp Pendleton included two Marines from California, one from Louisiana and one from Missouri.
The Marine Corps released the names Thursday night of the Marines killed while clearing unexploded ordnance at the base Wednesday.
The two Californians killed were 28-year-old Staff Sgt. Mathew R. Marsh of Long Beach, who had been a Marine since 2003, and 27-year-old Sgt. Miguel Ortiz of Vista, a Marine since 2006.
Also killed were 31-year-old Gunnery Sgt. J. Mullins of Bayou L'Ourse, La., an 11-year Marine Corps veteran, and 32-year-old Staff Sgt. Eric W. Summers of Poplar Bluff, Mo., who has been in the Marine Corps for 13 years.
The Corps also said one Navy Hospital Corpsman and two Marines near the accident had minor injuries.