The Army Sees Mortars as Safe. Troops Report Signs of Brain Injury.

After firing about 10,000 mortar rounds during four years of training, one soldier who joined the Army with near-perfect scores on the military aptitude test was struggling to read or do basic math.

Another soldier started having unexplained fits in which his internal sense of time would suddenly come unmoored, sending everything around him whirling in fast-forward.

A third, Sgt. Michael Devaul, drove home from a day of mortar training in such a daze that he pulled into a driveway, only to realize that he was not at his house but at his parents’ house an hour away. He had no idea how he got there.

“Guys are getting destroyed,” said Sergeant Devaul, who has fired mortars in the Missouri National Guard for more than 10 years. “Heads pounding, not being able to think straight or walk straight. You go to the medic. They say you are just dehydrated, drink water.”

All three soldiers fired the 120-millimeter heavy mortar — a steel tube about the height of a man, used widely in training and combat, that unleashes enough explosive force to hurl a 31-pound bomb four miles. The heads of the soldiers who fire it are just inches from the blast.

The military says that those blasts are not powerful enough to cause brain injuries. But soldiers say that the Army is not seeing the evidence sitting in its own hospital waiting rooms.

In more than two dozen interviews, soldiers who served at different bases and in different eras said that over the course of firing thousands of mortar rounds in training, they developed symptoms that match those of traumatic brain injury, including headaches, insomnia, confusion, frayed memory, bad balance, racing hearts, paranoia, depression and random eruptions of rage or tears.

The military is confronting growing evidence that the blasts from firing weapons can cause brain injuries. So far, though, the Pentagon has identified a potential danger only in a few unusual circumstances, like firing powerful antitank weapons or an abnormally high number of artillery shells. The military still knows little about whether routine exposure to lower-strength blasts from more common weapons like mortars can cause similar injuries.

Answering that question definitively would take a large-scale study that follows hundreds of soldiers for years, and it is impossible to draw sweeping conclusions from a handful of cases. But the soldiers interviewed by The New York Times have experienced problems similar enough to suggest a disturbing pattern.

Most soldiers said they had fired at least 1,000 rounds a year in training, often in bursts of hundreds over a few days. When they were new at firing, they said, they felt no lasting effects. But with each subsequent training session, headaches, mental fogginess and nausea seemed to come on quicker and last longer. After years of firing, the soldiers experienced problems so severe that they interfered with daily life.

Nearly all of the soldiers interviewed for this article never saw combat, but they were nonetheless haunted by nightmares, anxiety, panic attacks and other symptoms usually attributed to post-traumatic stress disorder.

Nearly all sought medical help from the Army or the Department of Veterans Affairs and were screened for traumatic brain injury, but did not get a diagnosis. Instead, doctors treated individual symptoms, prescribing headache medicine, antidepressants and sleeping pills.

That is in part because of how traumatic brain injuries, known as T.B.I.s, are diagnosed. There is no imaging scan or blood test that can detect the swarms of microscopic tears that repeated blast exposure can cause in a living brain. The damage can be seen only postmortem.

So, doctors screening for T.B.I.s ask three questions: Did the patient experience an identifiable, physically traumatic event, like a roadside bomb blast or car crash? Did the patient get knocked unconscious, see stars or experience other altered state of consciousness at the time? And is the patient still experiencing symptoms?

For a T.B.I. diagnosis, the answer has to be yes to all three.

The problem is that people who are repeatedly exposed to weapons blasts often cannot pinpoint a specific traumatic event or altered state of consciousness, according to Stuart W. Hoffman, who directs brain injury research for the V.A. With career mortar soldiers, he said, “if you’re not feeling the effects at the time, but you’re being repeatedly exposed to it, it would be difficult to diagnose that condition with today’s current standards.”

That means injuries that seem obvious to soldiers go unrecorded in official records and become invisible to commanders and policymakers at the top. As a result, weapons design, training protocols and other key aspects of military readiness may fail to account for the physical limits of human brain tissue.

An Army spokesman, Lt. Col. Rob Lodewick, said in a statement that for decades the Army has been studying how to make weapons safer to fire and is “committed to understanding how brain health is affected, and to implementing evidence-based risk mitigation and treatment.”

Asked if the Army plans to phase out the use of the 120-millimeter mortar, a mobile weapon that nearly all infantry units use to rain down bombs on enemy positions, Colonel Lodewick said no.

Still, there are signs that the Army sees problems with the mortar. It is developing a cone for the muzzle to deflect blast pressure away from soldiers’ heads. And in January, the Army issued an internal safety warning, drastically limiting the number of rounds that soldiers fire in training to no more than 33 rounds a day using the weakest charge, and no more than three rounds a day using the strongest.

That warning, though, makes no mention of brain injury; the stated purpose is to protect troops’ hearing.

The military measures the force of blast waves in pounds of pressure per square inch, and the current safety guidelines say that anything below 4 PSI is safe for the brain. The blast from firing a 120-millimeter mortar officially measures at 2.5 PSI. But the guidelines do not take account of whether a soldier is exposed to a single blast or to a thousand.

There are roughly 9,000 mortar soldiers in the Army — and, in all service branches, there are thousands more troops who regularly use weapons that deliver a similar punch: artillery, rockets, tanks, heavy machine guns, even large-caliber sniper rifles.

Justin Andes, 34, launched about 10,000 mortar rounds in Army training at Fort Johnson, La., between 2018 and 2021.

He began to experience migraines, dizziness and confusion, to such a degree that his job of keeping accurate counts of weapons in his unit’s armory became a struggle. Eventually he had an emotional breakdown with thoughts of suicide, and he left the Army in dismay when his enlistment ended.

“We had to keep a count of every round we fired, and get the mortar tubes inspected each year, because all those blasts can take a toll on the weapons system,” he said in an interview. “But no one was doing that for us.”

Mr. Andes joined the Army with a college degree and top scores on the military aptitude test. He had planned to get a graduate degree in political science, but after firing so many mortar rounds, he had trouble reading. Today, Mr. Andes, who now lives in Jefferson City, Mo., speaks with a slight slur, sometimes puts the milk in the kitchen cupboard instead of the refrigerator, and spends much of his time in his basement.

“His voice is different, he acts different, he is a different person from the man I married,” his wife, Kristyn Andes, said. “I didn’t start to connect the dots that this might be mortars until some of the other wives said they were having the same issues.”

The first sergeant in charge of Mr. Andes’ platoon, she said, was having trouble, too. He was forgetting words, struggling to remember his responsibilities and had a stammer in his speech and a tremor in his hand.

Another soldier in his platoon, James Davis, 33, started having near-daily panic attacks in uniform, as well as balance problems, migraines and sensitivity to light. He went to a specialty clinic for traumatic brain injury at Fort Johnson in 2022. “I was told that with time, the symptoms would disappear,” said Mr. Davis, who now lives in Colorado Springs, in an interview. “I am still waiting for that to happen.”

Mr. Andes, Mr. Davis and their first sergeant all left the Army without any official record that their brains may have been injured by mortar blasts. All three went to the V.A. for help. All three were found to be substantially disabled by issues that can be caused by traumatic brain injury, like vertigo, headaches, anxiety and sleep apnea. But not one was diagnosed with a brain injury.

Former soldiers who fired mortars in the 1980s and 1990s say their experiences show that the problems are not new and may not improve with time.

“It’s hard for me to piece together, because my memory has gotten so bad, but things are definitely getting worse,” said Jordan Merkel, 55, who joined the Army in 1987 and fired an estimated 10,000 mortar rounds over four years.

In uniform, Mr. Merkel started experiencing strange fugue states, where he would be awake but barely responsive and would retain little memory afterward of what had happened.

After the Army, he tried college but spent most of the time struggling through remedial classes. He married and divorced three times and said that he remembers very little about those relationships.

For years he worked testing security software — a job with a predictable routine that allowed him to get by. But in 2016, he forgot how to do his work: Procedures he’d been following for years drew a blank.

He was soon laid off, got a similar job and was laid off again. He has recently noticed trouble reading an analog clock.

“I’m really concerned,” said Mr. Merkel, who now lives in Harrisburg, Pa. “This is not normal aging, this is something else.”

He went to the V.A. this spring seeking help. The medical staff asked whether he had ever hit his head or been knocked unconscious, but they seemed dismissive when he brought up mortars, he said.

“They weren’t the least bit interested in discussing anything related to blast concussion,” he said.

Todd Strader had a similar experience. He fired mortars in the 1980s and 1990s at a U.S. base in Germany, and he developed headaches so severe that he would collapse on the ground and vomit. He was hospitalized in the Army for unexplained intestinal problems — a common issue among people with traumatic brain injuries.

As a civilian, he struggled with fractured concentration, fatigue and anxiety.

“I had plans for myself after the Army,” said Mr. Strader, 54, who now lives in Hampton, Va. “I wanted to travel the world but just ended up working a string of dead-end jobs.”

He went to the V.A. in 2019 and was told that there was nothing in his record to suggest a military service-associated brain injury. Instead he was diagnosed with PTSD, even though he had never been in combat.

Frustrated that the V.A. would not recognize what seemed obvious to him, he started a Facebook group, hoping to find other mortar soldiers with the same symptoms. The group now has nearly 2,500 members.

The Pentagon has repeatedly assured Congress that the military is giving new attention to blast exposure, but ordinary soldiers say they have seen little change.

Sergeant Devaul, who drove home to the wrong house, is now trying to get the Army to recognize that years of firing mortars injured his brain. He hasn’t had much luck.

At his kitchen table in Kansas City, Mo., on a recent morning, he described how for 18 years he fired mortars, and how his life slowly fell apart.

He started in the active-duty Army in 2006 and transferred to the National Guard in 2010. He deployed twice but never saw combat.

After years of firing, he started to have trouble thinking. He had a civilian job doing carpentry but struggled with the math and organizational skills and left in frustration. He worked as a security guard for several years, but he developed headaches and concentration problems, and had outbursts of rage.

Then he got a break from firing. For much of 2017 and 2018 he was in Qatar on a mission with no mortars and then in training away from the mortar range. He began feeling clearer and calmer. He studied to become an emergency medical technician and, in 2019, got a job with his local fire department.

But that summer he resumed firing mortars. He started struggling to remember where supplies were kept in his ambulance. Other firefighters told him that he seemed to spend much of his time staring at nothing. The department asked him to learn to drive a fire truck, but he doubted that he could pass the test.

In the fall of 2021 he was firing mortars in a training exercise and suddenly felt as though a seam had split in his head. He was dizzy and sick. For weeks afterward, he said, his skull was throbbing, and he was confused and angry.

“I felt worthless and stupid,” he said. “I was so exhausted I could barely get off the couch. I didn’t see it getting better.”

His wife filed for divorce. He became suicidal and spent five days in a program for PTSD.

At his next National Guard training, it took only a few blasts to put him on the ground with the world spinning.

The Guard now lists him as temporarily disabled by what it calls “post-concussion syndrome.” He is not allowed to fire mortars or even rifles.

Since Sergeant Devaul can’t do his military job, the Guard has begun the process of discharging him. If it decides his injuries are service-related, he’ll be medically retired with lifetime benefits. If not, he’ll be forced out with next to nothing.

Sergeant Devaul met recently with his brigade’s surgeon to be evaluated for traumatic brain injury. He said the doctor seemed skeptical that firing mortars could cause his symptoms.

“I kept asking, ‘What else could have caused it?’ He didn’t have an answer,” he said. “I’ve got every single symptom of a traumatic brain injury. I just don’t have a diagnosis.”