Seven US marine training deaths caused by 'human error'
Human error caused a mortar explosion that killed seven US marines in a training accident in Nevada in March, military investigators have found.
The mishap occurred when a marine using a 60mm mortar tube and ammunition did not follow procedures, it said.
The team had not been adequately trained before the night time live-fire drill at the Hawthorne Army Depot, the investigation concluded.
Two officers and a non-commissioned officer have been disciplined.
Those caught in the 18 March blast, which also wounded eight marines, were part of the Second Marine Expeditionary Force.
"The investigation established that human error was the cause of the mortar mishap," the Marine Corps said in a statement.
"The marines employing one of the mortars did not follow correct procedures, resulting in the detonation of a high explosive round at the mortar position."
The report also found: "The mortar section had not conducted appropriate preparatory training."
But the investigation found the equipment had been working properly and "found no reason to question the safety of the system when it is employed as designed and as marines are trained to employ it".
Lt Col Andrew McNulty, the commanding officer of Marine Corps battalion, was dismissed from his post on 8 May, the statement said.
Two others involved in the training, Capt Kelby Breivogel and Chief Warrant Officer Douglas Derring, were also relieved of their duties.
The Marines said no charges were anticipated in connection with the incident.