Wednesday, March 27, 2013 | 2 a.m.
The probe into what caused a 60mm mortar round to misfire during a training exercise at the Hawthorne Army Depot, killing seven Marines and injuring eight, has entered its second week, with the Marine Corps still banning use of the weaponry with a shadowy past.
Military investigators have identified and removed from circulation the lot from which the shell came. The shell detonated prematurely March 18 as the Marines, being prepared for oversees deployment, huddled around for instruction on its use.
The lot was manufactured in 2010 at the Milan Army Ammunition Plant in Milan, Tenn. It consists of 15,000 rounds, all of which were stored at two locations: Hawthorne and an Army munitions complex in Crane, Ind.
Military officials won’t discuss what their investigation has found so far. But discussions with experts, veterans and service personnel suggest that their search will boil down to just a handful of options, from human error to weapons failure to worse.
“It can be a problem with the training regimen,” said Joseph Trevithick, a research associate with globalsecurity.org. Troubles could occur “if the training regimen isn’t clear or personnel weren’t properly trained, or somebody was doing something they shouldn’t have been doing.”
Stephen Abney, a spokesman with the Army Munitions Joint Command, said the mortar round itself, or the tube that the mortar is dropped into to be fired, could be the problem.
But others scoffed at that notion.
“These are long-proven weapons, so there’s no reason for them to become dangerous,” said Bob Gravett, making particular note of the Marines’ system-wide stop-use order on the 60mm mortar system in question. “But the U.S. military doesn’t do anything without a damn good reason, with mortars being such a staple for so many years.”
Mortars — explosive projectiles that are lobbed from metal tubes to reach indirect targets at short distances — are a staple weapon of conflicts such as that taking place in Afghanistan.
“People hide behind rock outcroppings and such,” Trevithick said. “Mortars remain a large part of getting to people behind hard cover.”
The newest model of mortar system, the M224A1, came online a few years ago and is being rolled out to all corners of the Army and Marines — a timeline that lends itself to supposing the accident could be the result of a glitch in the updated components.
But the history of the 60mm mortar goes back to the Second World War — and particularly at Hawthorne, that’s cause for some confusion, and potentially concern.
Hawthorne rose to prominence during World War II as a staging area for most of the bombs, rockets and other ammunition that were employed during the war. It also has served as a hub for American war materiel being shipped to the front in Korea, Vietnam and Iraq. Today, Hawthorne receives munitions from the Army’s western distribution center in Tooele, Utah, before shipping materiel to Afghanistan.
But Hawthorne isn’t just a staging area for new weapons; it’s also a storage facility for old weapons that don’t get fired or detonated, long after the conflicts for which they were destined is over.
“War reserve, long-term storage demilitarization,” Abney said. “That is really what Hawthorne’s for. That’s its main mission.”
Abney stressed that the military keeps meticulous track of what mortars are cataloged for demilitarization — defusing and de-fanging, essentially — and which are destined for use, either in the theater of combat or for a training, such as the one for which the munitions depot was hosting Marines from Camp Lejeune last week when the explosion took place.
“When the Marines train here ... because it kind of looks like Afghanistan, it’s the high desert ... they draw the ammo here. And it’s not the old stuff when they draw it; it’s modern,” Abney said. “They say, ‘We need some of this, some of that,’ and we go to the bunker and issue it to them.”
The Marine Corps says the mortar system used in the training accident was the newest model, the M224A1.
The nearby presence of older 60mm mortars, however, has many speculating whether the entire episode was the result of misfiling or a case of curiosity gone catastrophic.
Mortars, especially 60mm mortars, have a storied history in the U.S. military. Their usefulness in rugged terrain has made them a common feature of the land war materiel portfolio.
But their ubiquitousness has also made them a sometime tool for dirty tricks, particularly during the Vietnam War.
Some Nevada veterans are asking whether the Marines could have been using shells designed to explode when dropped into the firing tube, a tactic of intentionally booby-trapping mortars that was widely used during Vietnam and, some presume, may still be employed today. (The New York Times last year reported the practice of booby-trapping ammunition in the Syrian civil conflict.)
Army Ret. Lt. Col. William Shelton of Las Vegas, who once commanded a group of Green Berets, said he worked with Central Intelligence Agency operatives in South and North Vietnam, Laos and Cambodia to salt enemy munitions with doctored bullets and mortar shells that would explode in the hands of the operator when he attempted to fire them.
Among the tactics: removing the bullet tips off rounds of Chinese-manufactured ammunition and replacing the firing powder with a more explosive compound. The booby-trapped rounds typically would then be placed back in the ammo belts and clips of fallen enemy soldiers that would later be retrieved and used by other enemy troops, only to explode in their hands when firing their weapon.
When such doctoring involved mortars, the tweak would affect the trigger mechanism for instant versus delayed detonation, ensuring that the shell would detonate the moment it hit the bottom of the firing tube.
Guido Deiro, a pilot who worked for the Hughes Tool Co. and says he spent years involved in U.S. government covert operations overseas, worried that one or more of the booby-trapped mortars might have wrongly been returned by troops for storage at the Hawthorne facility.
Experts who have documented the past and continued use of such doctored devices, however, describe their effectiveness as “sporadic” at best and say there’s no reason to speculate that anything of the sort would have ended up in the hands of Marines training at Hawthorne.
“The chance of it being a booby-trapped ordnance I would think ... they would control that batch of ordnance so closely it wouldn’t get into anything,” said Gravett, adding that the only plausible circumstance for such an accident “would be if a souvenir brought back by someone was sometime later used in one of these redneck shoot-em-up weekends.”
“Which is why I think it’s more likely to be a standard accident, an unfortunate event surrounding the 60mm mortar,” Gravett said. “Of course nothing is beyond the realm of possibility.”
The military categorically rejects any theory that connects booby-trapped weapons with last week’s blast, explaining none was stored at Hawthorne and pointing out that the military had already identified the highly explosive mortar lot that was involved in the accident.
Referring to the 60mm mortar systems manufactured in Tennessee, Abney said: “All of the ammunition that was made at that location, made by final assembly at that location using the same batch of propellant and explosive and metal parts and fuse; all of that, that’s suspended. Engineers will look in detail at it and then they’ll do additional sampling on other rounds from that lot and check it out. If there’s a problem in the lot, we’ll put it in the demilitarization account.”
While the Army was satisfied at suspending use of mortar shells in that particular production lot, the Marines’ decision to suspend use of all 60mm mortar systems reflects its perspective that the mortar rounds are only one factor in the firing system.
“If it detonated in the tube, something definitely has gone amiss,” Gravett said. “I can imagine something got hung up in the tube and the next mortar bomb is what (detonated) it. ... If someone has dropped one (round) in and it’s got a faulty shotgun tube, it’s still in the bottom when the (next) round drops. Then you’ve got an interesting situation.”
Regardless of the outcome of the investigation, the accident has come as something of a shock to the military and the Hawthorne training facility, which has a strong training safety record when it comes to mortars and has invested in them as a light, powerful tool of war.
“I think we haven’t had a problem in 15 years with these,” Abney said.
While the military has substitutes for the 60mm mortar — heavier mortars, for example, grenade launchers and portable missile systems can often achieve the same desired indirect-target effect — it is a fundamental enough feature of the combat soldier’s arsenal that officials will be eager, once they have answers about what happened at Hawthorne, to get it back online.
“It is, in the scheme of things, one of the most simple-to-operate weapons available. It is practical and it is useful,” Trevithick said. “They do have other capabilities, but it could potentially have an effect.”
Demirjian reported from Washington, Gorman from Las Vegas.