The Marine Corps says a dropped or kicked grenade probably caused an explosion that killed four Marines during a training exercise last year at Camp Pendleton.
Capt. Ryan Welsh says a captain and master sergeant were relieved of duty this week for failing to properly conduct the Nov. 13 training exercise at the California base. He says among other things, they allowed Marines to hand each other live ammunition as they gathered unexploded rounds from a firing range for demolition.
A report released Thursday says the accident probably occurred when a 40 mm grenade was dropped, kicked or bumped, causing it to explode and set off dozens of other rounds.
Welsh says a Marine official has ordered immediate changes in ordnance disposal training at Pendleton and three other Western bases.