A government watchdog will probe the Pentagon’s efforts to identify, treat and prevent traumatic brain injuries caused by blast exposure.

The Government Accountability Office has accepted a request from two dozen lawmakers in both parties and chambers of Congress to conduct a review in response to their concerns that the Pentagon is not taking the issue seriously enough, according to a copy of a letter the GAO sent to the lawmakers that was obtained by Military.com.

“DoD has spent billions on researching traumatic brain injuries, but there are still major gaps in getting service members the help that they deserve,” Sen. Elizabeth Warren, D-Mass., said in a statement to Military.com about the GAO agreeing to investigate. “We must act to protect our service members, and the GAO will help us review those efforts and identify key areas to mitigate the impacts of blast overpressure on service members.”

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The GAO expects to formally start its review in about four months, according to the letter.

The request — which was led by Sen. Joni Ernst, R-Iowa, and Reps. Ro Khanna, D-Calif., and Elise Stefanik, R-N.Y., in addition to Warren — came after a hearing earlier this year in which Pentagon officials frustrated senators with a seeming lack of urgency in addressing a top health concern for service members.

At the hearing, held by the Senate Armed Services Committee’s personnel subcommittee chaired by Warren, Pentagon officials vowed to collect more data on troops’ exposure to blasts. But they also said more research would be needed before taking some of the steps that lawmakers were advocating for, such as more frequent cognitive testing and defining safety limits for using certain weapons.

Lawmakers have been pushing for more immediate action amid a growing pile of evidence detailing the devastating symptoms service members and veterans are suffering as a result of traumatic brain injury, or TBI. Mounting evidence also indicates that troops are at risk of exposure to dangerous blast pressure not just from enemy bombs and attacks but also from routine military activities such as repeat artillery fire.

Military.com has reported extensively on evidence that TBI is linked to an increased risk of suicide among veterans and that Pentagon officials squandered opportunities to get ahead of the issue.

In addition to pushing for a GAO investigation into the issue, Warren, Ernst and Khanna introduced a sweeping bill earlier this year intended to better prevent and treat TBI among service members.

Elements of that bill were included in both the House and Senate version of the annual defense policy bill. The defense bill is working its way through Congress right now, with a full Senate vote pending followed by negotiations between the House and Senate on a final version that will become law.

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