The Pentagon has quietly sidelined a program that placed blast gauges on thousands of combat troops in Afghanistan. The monitoring was discontinued because the gauges failed to reliably show whether service members had been close enough to an explosion to have sustained a concussion, or mild traumatic brain injury.
But the small wearable devices did produce a trove of data on blast exposure. They produced evidence that many service members are exposed to worrisome levels of blast pressure simply by being near a heavy weapon when it’s fired. “The majority of exposures were not from improvised explosive devices, as you might expect,” says David Borkholder, an engineering professor at the Rochester Institute of Technology and the founder of BlackBox Biometrics, which makes the blast gauges. Instead, the culprit was usually “blast-intensive weapons systems” like recoilless rifles, shoulder-fired rockets, artillery and mortars, he says.
The reason is pretty simple. Firing something like a recoilless rifle generates a powerful pressure wave both in front of and behind the weapon. Those pressure waves are usually less intense than those from a bomb, Borkholder says. But exposures are far more common, and not limited to the battlefield.