The Marines released the identities of the dead Wednesday, the Los Angeles Times reported. Seven Marines and a Navy sailor were injured when a 60 mm mortar round exploded late Monday.
The Marines on the scene behaved in a manner that was "nothing short of heroic," Lt. Col. Andrew McNulty said in a statement.
"There were numerous acts of selflessness as our injured cared for each other and directed corpsmen to care for more severely injured before being treated themselves,'' McNulty said.
The injured had not been identified Wednesday. Officials said the Navy man was in very serious condition, five of the Marines were in serious condition and two had been treated and released.
The dead were listed as: Pfc. Joshua M. Martino, 19, of Clearfield, Pa.; Lance Cpl. David P. Fenn II, 20, of Polk City, Fla.; Lance Cpl. Joshua C. Taylor, 21, of Marietta, Ohio; Lance Cpl. Mason J. Vanderwork, 21, of Hickory, N.C.; Lance Cpl. William T. Wild IV, 21, of Anne Arundel, Md.; Lance Cpl. Roger W. Muchnick Jr., 23, of Fairfield, Conn.; and Cpl. Aaron J. Ripperda, 26, of Madison, Ill. All were based at Camp Lejeune in North Carolina.
Fenn, Muchnick, Taylor and Vanderwork had all been deployed to Afghanistan.
The Marines said the cause of the explosion is still being investigated with McNulty saying in a statement the mortar system "failed to function as designed."