William Milzarski was 40 years old when he ​finished his infantry training. His two sons had enlisted, and he felt a midlife crisis coming on. “It was either enlist, or buy a red convertible,” he says. Shipped off to Afghanistan, Lt. Milzarski led his platoon into 244 combat missions, until a bullet ricocheted off a rock during a firefight and hit him in the face. He stayed with his troops, wounded and bloody, until the battle was over. Then, seven months later, he rotated home.

The wound healed, the scar covered by the stubble of his beard. It was another three years, however, before he realized that the distance he felt from everyone and everything was not simply a symptom of PTSD. He was also going deaf—his hearing yet another casualty of war.

It was difficult to admit that something that seemed so trivial at first could be so serious. “I got shot in the face, and I stayed with my men,” he says. “And now, this? It never seemed bad enough—and that’s the problem.”

Today, the Department of Veterans Affairs ranks hearing loss as the number one disability among vets. At least 60 percent of those returning from Iraq and Afghanistan—some 600,000 vets—suffer permanent hearing loss or tinnitus, a chronic ringing in the ears. It’s also the fastest-growing of all postwar disabilities, more than doubling over the past decade, and among the most costly in terms of lost productivity. Lose your hearing and you’re more likely to lose your job, suffer from high stress, or experience social anxiety, depression, and early-onset dementia. And though it can be treated, there is no cure.

Soldiers are suffering from hearing loss for a simple reason: War is loud, and getting louder. The F-35 fighter jet, which was declared operational in 2015, is among the most deafening flying machines ever created—four times louder than the F-16. It’s so loud that aircraft carriers need to be specially outfitted with extra sound-dampeners to protect the ears of sailors, even below deck. In Vermont, where the F-35 is scheduled to be deployed in 2019, an initial Air Force evaluation found that the jet’s decibel level during takeoff and landing would render 1,366 homes in the area “unsuitable for residential living.”

More firepower also means more noise. The crack of the military’s standard-issue pistol, the M9, is nearly as loud as the F-35. And the Mach 7 boom of the Navy’s new rail guns and other “kinetic weapons systems” are eight times louder than traditional artillery systems.

The military is even attempting to harness noise as a weapon: The Joint Non-Lethal Weapons Program is currently working on a sonic device known as the Laser-Induced Plasma Effect, which fires nanosecond bursts of energy at 130 decibels. Hearing loss can begin to occur at as little as 85 decibels—the sound of heavy city traffic.

The nature of warfare makes it difficult to protect troops from noise. Sudden blasts tend to do more damage to the eardrum than a constant hum—and loud blasts are a central element of today’s ambush style of warfare. Current combat helmets don’t protect ears from loud blasts, unfortunately. And they can also muffle a soldier’s hearing, making it harder to locate and evade threats.

The military knows it has a serious problem—but addressing it has proven difficult. In 2009, the Defense Department created the Hearing Center of Excellence, which now serves 700,000 veterans of current and past wars who were diagnosed with hearing loss in the past decade, and 840,000 who suffer from tinnitus. But the gung-ho culture of the military makes many soldiers suffering from early-stage hearing loss reluctant to seek assistance. Veterans often wait decades to get help—allowing a relatively simple problem to spiral into something far more severe. “There are significant gaps in the military’s ability to treat this type of injury,” says Col. Mark Packer, director of the Hearing Center.

The military is also working to design combat helmets that boost ambient noise while muffling loud blasts—effectively enhancing a soldier’s ability to hear while protecting his ears from damage. The helmets are being tested at the Environment for Auditory Research, or EAR lab, at the Aberdeen Proving Ground in Maryland, where gas masks were invented.

To demonstrate the challenges involved, Angélique Scharine and Mark Ericson, two auditory researchers, escort me to a room where 57 loudspeakers are arrayed in a sphere. In the middle is a swivel chair with a laser pointer attached. I sit in the chair and put on a prototype helmet, while the researchers boot up a demo. Suddenly, noise fills the room. Cars honk. People chatter. In the distance, something metal- sounding rumbles.

“This is Times Square!” Ericson shouts above the din. “Now, point to the cricket chirp!”

Behind me, I hear the faint hint of a cricket chirp. I swivel and shoot the laser pointer where I think the cricket might be.

When the demo is over, Scharine shows me the results. I wasn’t even close. That’s because any equipment like a helmet interferes with our brain’s natural ability to rapidly calculate a host of minor reflections and frequencies to determine the direction and approximate distance of important sounds.

“It’s hard, the longer you take to figure out where the sound is, or how far off you might be,” Scharine says. “Because in combat situations, even a small error can be a big, life-ending error.”

That’s why it may prove impossible for the military to research its way out of the noise problem. Better combat helmets won’t help, after all, as long as there’s a disincentive to put them on. For now, Milzarski says, soldiers will be trading their helmets for hearing aids when they come home. “I’m on the crest of this wave,” he says. “And it’s only going to get worse.”

But Milzarski doesn’t want to make it sound too bleak. He is sitting out on his porch, enjoying the evening. His new hearing aids work great, he says, and the attachment he uses for his phone calls is nearly perfect. “And here’s something,” he adds. “I no longer hear mosquitoes! It’s one of those things I never noticed I missed—and now that I can’t hear them, they don’t bother me as much.” He laughs. “Little blessings,” he says.