Editor’s note: this article by Hope Seck first appeared on Sandboxx.

A five-pronged Defense Department study involving more than 600 soldiers and Marines as human test subjects is inching the department closer to fulfilling a congressional mandate to include blast exposure from training and combat operations in a service member’s medical record. 

The study, which began in 2018, found that even firing weapons repeatedly in conventional stateside training could produce symptoms of traumatic brain injury. And while monster blasters like the Carl Gustaf recoilless rifle topped the list of weapons most capable of creating harmful blast overpressure effects, even sniper rifles could do damage over time, officials said.

“In addition to breaching [weapons], of which we have longstanding research data that suggests [they are] problematic for temporary health and performance changes, there’s also these other categories of weapons that people are training on every day,” Kathy Lee, Warfighter Brain Health Initiative Lead for the office of the Assistant Secretary of Defense for Health Affairs, told Sandboxx News.

The work is timely. An academic paper published in January 2022 found that up to 22% of troops from recent conflicts suffered from mild traumatic brain injury, or mTBI, and the most prevalent cause was long-term exposure to explosive weapons.

The Pentagon sent an update to the congressional Armed Services committees in December outlining ongoing study efforts. It also mentioned the difficulty of quantifying military training hazards and operations long known to produce debilitating long-term effects in troops; these effects can range from dizziness and confusion to mood swings and insomnia. The fiscal year 2020 National Defense Authorization Act required the DoD to start including blast exposure history in troops’ medical records, and also called for a report from the defense secretary no later than a year after the bill’s passage on the specific information that would be reported.

“There has not been any surveillance or documentation of brain exposure to blast overpressure due to limitations in the ability to measure and characterize the hazard of such exposures,” Gil Cisneros, Under Secretary of Defense for Personnel and Readiness, wrote to the committee chairs.

“This disparity, however, is being rectified by the Department as significant progress has been made to integrate the environmental surveillance and documentation of historical blast pressure exposure data of our Service members with clinical provider access for entry into medical records,” the under secretary added.

In 2021, 383 soldiers with the 101st Airborne Division participated in a pilot study focused on data collection at Fort Campbell, Kentucky. They wore small blast gauges during heavy munitions firing operations that tracked both blast overpressure exposure and efforts over the course of a single day, and longitudinally during three to four months of normal training.

military blast exposure measurement guages
Small, wearable blast measurement gauges show the damages incurred during a recent study of blast pressure exposure at Fort Campbell, Kentucky on Oct. 28, 2022. (U.S. Army photo)

A second comparison study, completed in the summer of 2022, involved 200 troops at Marine Corps Air-Ground Combat Center Twentynine Palms, California.

Navy Capt. Scott Cota, division chief at the Pentagon’sTraumatic Brain Injury Center of Excellence, said researchers also paid attention to the experience and exposure levels of the training staff – called “coyotes” at Twentynine Palms – who run training for the ground-pounders. The researchers wanted to ensure not only that training staff could accurately record blast data, but also that they could do so in a way that fit into training and could be executed by range managers. 

“So you could say, ‘OK, if you stand here, you’re going to get this kind of exposure; if you’re the primary person firing it, you’re going to get this kind of exposure,’” Cotta said. “So now we can prejudice it in a modeling scenario, and put it into the pre-planning phase, so that if those range managers want to initiate mitigation actions… they can use that in their decision-making.”

How to transfer the data collected on blast gauges in a consistent and accurate way into a central database was another focus.

Cota said the task was more complicated than it sounded: researchers needed to record data points including how close an individual was to a weapon, their firing position, the weather and location of the shoot, and any previous exposures that might exacerbate blast effects. 

“And then, he said, “being able to just de-identify and move that data into the system so that it would end up in the medical record for evaluation and also development of unit types of reports for immediate feedback or near-immediate feedback within a few days.”

Spc. Jacob Pinola, a cavalry scout assigned to C Troop, 3rd Squadron, 4th Cavalry Regiment, 3rd Infantry Brigade Combat Team, 25th Infantry Division fires a Carl Gustav recoilless rifle during a live-fire training event at Pōhakuloa Training Area, Hawaii Feb. 10, 2022. (U.S. Army photo by Staff Sgt. Brendan Spangler)
Spc. Jacob Pinola, a cavalry scout assigned to C Troop, 3rd Squadron, 4th Cavalry Regiment, 3rd Infantry Brigade Combat Team, 25th Infantry Division fires a Carl Gustav recoilless rifle during a live-fire training event at Pōhakuloa Training Area, Hawaii Feb. 10, 2022. (U.S. Army photo by Staff Sgt. Brendan Spangler)

In his letter, Cisneros said the Defense Department hadn’t yet completed the necessary work to accomplish the medical history tasker.

“At the time this report was written, technical developers continue to work on refining the data extraction of the relevant exposure information,” he wrote. “In addition, DoD is validating storage requirements for the amount of blast data and modifying data mapping and data exchange protocols to ensure visibility from DoD to the Department of Veterans Affairs (VA).”

The officials who spoke with Sandboxx News said the release of interim findings, even as work on the main objective continues, allows military units and training managers to implement mitigation measures for those who might be at risk.

A recently published DoD-wide memo announced the finding that blast pressures as low as four pounds per square inch (PSI) could affect the mental functioning of service members, resulting in mild reported symptoms such as brain fog, Cota said. While training and deploying with heavy munitions entails blast exposure, Cota and Lee said there are a number of steps outlined in the memo that can minimize negative effects without reducing necessary training.

Most of the steps to minimize negative effects from blasts are “common sense” he said. “Like stand farther away, if you’re training cadre and you don’t need to be right near the weapons system. Increase distance between firing units, so they’re not getting secondary exposures. [Or] don’t have combatives training immediately following a firing range.”

While it’s not yet clear when the DoD will be ready to meet the mandate to include blast overpressure events in a service member’s medical history, Lee said the Warfighter Brain Health Initiative will continue over the next four years to implement 53 recommendations intended to protect troops’ brains throughout their careers.

“We want to monitor those brain threats, document them, and understand how we can mitigate and use countermeasures to try to decrease the brain threats that are inherent in our environment in which military folks work,” she said.

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