Each three pack of blast gauges is worn on a helmet, as well as the service member’s arm and chest. (Courtesy of DARPA​/​)

The motion-activated doors opened with a soft hiss as the soldier walked into the emergency department at Kandahar Airfield in Afghanistan.

He was covered in dust, a bandage affixed to his neck, his pants shredded.

A doctor stared, giving him a once-over before asking what happened.

“I got blown up,” the soldier said, staring right back.

“Blown up.” For centuries, soldiers have known the ravages of that phrase.

Jeffrey Rogers (Courtesy of Jeffrey Rogers)

Now, however, there is a piece of equipment that can determine how “blown up” a person might be, a tiny device that measures an explosion’s pressure on the human body as it happens.

The bottle cap-sized monitor, called a blast gauge, is the byproduct of a project started in 2009 by Jeffrey Rogers, a physicist and former project manager at the Defense Advanced Research Projects Agency. The gauge is small, black and almost war-proof, and at $150 a set, they come three to a pack. One goes on the back of the soldier’s helmet, and the other two are attached to the chest and arm.

Post-blast, the device is checked by pressing a single button that causes it to light up like a traffic light. Green is good, meaning little-to-no exposure to the blast’s pressure. Red is bad, meaning the gauge has been exposed to harmful levels of blast waves.

For his efforts, Rogers — who has since left DARPA and now works for Google — is a finalist for a Samuel J. Heyman Service to America Medal. The award, one of many for a variety of categories (he is a finalist in the category of science and environment), is presented annually to celebrate excellence in federal civil service. The winners will be announced in late September.

Rogers attributed the device’s creation to a misread phenomenon during explosions that the U.S. Army was exploring as the war in Iraq heated up.

“The Army was focusing on acceleration,” Rogers said. “But it’s not like the movies, acceleration wasn’t the right thing to look at, it was overpressure.”

As a physicist and project manager at DARPA, Rogers quickly identified off-the-shelf components that could make a gauge to measure pressure created from a blast and went to work. Eleven months later, he had a working prototype that he then issued to special operations units in Afghanistan.

“We showed people what was actually happening in these events, as opposed to what they thought was happening,” Rogers explained.

Shortly after the first unit deployed with prototype gauges, the vice chief of staff of the Army at the time, Gen. Peter W. Chiarelli, saw the device on a number of troops while visiting Afghanistan. After learning what they did, he personally called Rogers at DARPA and asked for a brigade to be immediately outfitted with them.

Within the year, more than 12,000 troops from various branches were using the devices.

For Navy Lt. Cmdr. Josh Duckworth, the attending neurologist for the Kandahar emergency room that day in the summer of 2011, quickly recognized that the dusty soldier standing in the sun-soaked doorway was wearing his blast gauges.

The soldier, Duckworth would recall, was the first individual to be exposed to a blast in combat while wearing the gauges, which provided an example of its ability to capture an event that usually lasts mere seconds.

The soldier’s story was spotty, Duckworth recalled. He had been on a foot patrol in the volatile Helmand province when his mixed unit of Afghan National Army and U.S. Army soldiers stopped to investigate what appeared to be an improvised explosive device lying on the side of the road.

He told his patrol to stop and stay put as he called the bomb’s location in on the radio. But as he went to key the handset to talk to his command, the device exploded behind him. A number of Afghan soldiers were wounded, and the soldier’s best friend was killed.

When Duckworth plugged in the three blast gauges, he saw that pressure from the explosion had hit the soldier from behind, dissipating around him before reverberating back off a nearby wall. His gauges showed yellow, meaning he was exposed to a moderate amount of pressure from the blast.

Duckworth remembers that the soldier had muttered something about it being his fault, a sentiment the men in his unit echoed as they thought the device exploded because the blast gauge-wearing soldier had used his radio the same moment the bomb went off. The theory, they thought, was that the radio waves had triggered the bomb. What Duckworth realized from the gauge’s data, however, was that the blast came from about three feet off the ground, indicating someone had picked up the bomb and caused it to go off.

“It wasn’t the soldier’s fault,” Duckworth said. “The device let me see that the blast waves originated at waist level.”

After squashing the rumors about the incident, Duckworth’s further examination of the data helped him to differentiate between medical issues associated with the blast and potential mental ones.

“I was medically able to understand what his blast exposure and what some of his symptoms were,” Duckworth said. “He had a lot of overlay with post-traumatic stress, and the gauges helped us tease the two apart.”

Duckworth, who has worked with Rogers extensively on the gauges, is now working on a number of studies that use the data obtainable from the gauges with advanced brain-mapping systems to learn more about post-blast effects and traumatic brain injuries.

Yet, while the gauges have been proven invaluable in combat, Rogers has said most incidents involving harmful amounts of overpressure from blasts occur in training. During exercises, soldiers are constantly buffeted with shock waves from rockets, artillery and other explosives. It is in non-combat situations that Rogers believes the blast gauge will continue to prove the most valuable.

“Of the initial 50,000 gauges returned, it turns out that three quarters of blast exposures happened in training as opposed to combat,” Rogers said. “The IED strikes and rocket-propelled grenade attacks are terrible but extremely uncommon.”

Rogers hopes the gauge data will lead to safer training environments and better practices for potentially harmful training scenarios.

“This was one of my smallest projects,” Rogers said. “But it matters because it affects those in the fight today.”