The Army's set to roll out a new explosive for large-caliber munitions; military-funded developers estimate that it'll nudge out TNT "within a decade."

Called IMX-101 (which stands for Insensitive Munitions Explosive) the explosive is one successful result of a four-year Pentagon-funded effort that sought to replace TNT – military munitions' longtime staple. First to go will be M795 artillery projectiles: 1,200 produced with IMX-101 instead of TNT will be delivered to the Army and Marine Corps by 2011.

The appeal of eliminating TNT comes down to safety, both in transport and storage. The compound's extreme volatility means that a TNT-loaded munition will detonate, with fatal implications, if struck by an IED or a rocket-powered grenade. In Iraq and Afghanistan, where both threats are everyday occurrences, that's an ongoing safety risk – one that's accompanied by significant costs to store and transport TNT while trying to minimize danger.

"But with IMX-101, all that would happen is the explosive would deflagrate (burn quickly), and the shell would break into a few pieces," Charlie Patel, a program-management engineer for Project Manager Combat Ammunition Systems, says of the key difference between the two explosives. "You wouldn't have the big detonation that would wipe out the vehicle and driver or a whole storage area and crew."

IMX-101 is just as lethal as TNT, and was the least expensive and safest alternative to TNT among 23 options – submitted by government agencies and private companies after a 2007 military solicitation – all of which were tested by a team of scientists and engineers at Picatinny Arsenal.

Successfully producing a less sensitive explosive, in this case, was a question of ingredients. IMX-101, developed by BAE Systems, is more thermally stable than TNT. "We're taking the conventional explosive and replacing it with a group of ingredients that are less sensitive," Philip Samuels, a Picatinny chemical engineer, says in a press release.

Two of the ingredients, DNAN and NTO, started undergoing manufacture by BAE researchers in 2001, in the early stages of efforts to replace TNT. The production was spurred by a realization among BAE's scientists that "try[ing] to make a safer TNT-based explosive," was largely impossible. Whenever they tried, the new explosive wasn't nearly as powerful. Instead, they opted to "find a way to produce the potentially more suitable, but not readily available, insensitive replacement for TNT."

And since the Army's already got a facility at the Holston Army Ammunition Plant that's producing DNAN and NTO – it's where BAE started manufacturing the compounds – the transition to IMX-101 is financially feasible, especially once production scales up. And the explosive has already passed a two-year battery of tests, including attacks from rocket-propelled grenades, in which projectiles loaded with IMX-101 were able to thwart "propagation from one round to another," which would otherwise yield accidental, potentially lethal, explosions.

Here's hoping the tests were as thorough as they sound: Picatinny researchers took the liberty of fast-tracking IMX-101 approval, paring what's typically a five-year test period down to only two. But if all goes according to plan, IMX-101 will soon be in storage, transit and use overseas – in larger quantities than TNT, and closer to troop quarters too. And BAE is already prepping a version for 105mm M1 cartridges.

“This is just the beginning,” Samuels says. “Over the next 10 years, I could foresee TNT being totally gone.”

Photo: U.S Army