The event is filmed at 10,000 frames per second. Playing back the footage at 15 or 30 frames per second allows the researchers to step inside the half-second lifespan of the event. Now we can see what in real time we could not. First the boots flatten, their sides bulging noticeably. An index finger rises from where it was resting on a thigh, as though the cadaver were about to make a point. The lower legs extend and rise. The head comes down and the arms shoot out in the manner of a hurdler mid-leap. Coates reverses the footage and directs me to watch the spine. As the energy of the blast moves to the seat pan, the dead man’s pelvis rises, shortening his torso and expanding his paunch. Underbody blast can compress a seated soldier’s spine by as much as two inches. Back pain and injuries, no surprise here, are common.
Played at this speed (and in this outfit), it’s modern dance. There’s grace and beauty to the limbs’ extensions, nothing brutish or violent. In real time, though, the forces that move the limbs pass too quickly for the tissue to accommodate. Muscles strain, ligaments tear, bones may break. Imagine pulling apart a wad of Silly Putty. Pull slowly, and it will stretch across the room. Yank it fast and it snaps in two. Likewise, different types of body tissue have different strain rates. For the forces of any given blast, one type may stretch, say, a fifth of its length without tearing, while another may manage just 5 percent. WIAMan will be calibrated to reflect these differences and predict the consequences.
The long-term quality of a soldier or Marine’s life is a relatively new consideration. In the past, military decision makers have concerned themselves more with go/no-go: Do the injuries keep a soldier from completing her mission? Have we lost another pawn in the game? WIAMan will answer that question, but it will answer others, too. Is this soldier likely to have back pain for the rest of his life? Will he limp? Will his heel hurt so much that he’d rather lose the foot? The answers may or may not affect the decisions that are made, but at least they’ll be part of the equation for those inclined to do the math.
BACK IN Building 336, I ask my hosts if it would be okay to try driving a Stryker. It would not. Like an obliging parent, Mark allows me to sit in the driver’s seat and turn the steering wheel back and forth. While everything else within reach seems robustly military-grade, all toggle switches and steel, the steering wheel appears to have been salvaged from a 1990s budget rental car. (And possibly was: General Dynamics, manufacturer of the Stryker, owns Chevrolet.)
Mark ousts me from the driver’s seat so he can repark the vehicle. Brockhoff, pacing at the edge of the parking lot, has found some sort of plastic packing material. She darts over to the Stryker and stuffs it in behind the backmost tire. What follows is a noise you will find nowhere in the publications of military hearing professionals: a 40,000-pound Stryker backing up over an armload of wadded-up bubble wrap.
3. FIGHTING BY EAR
The Conundrum of Military Noise
THE UNITED STATES MARINE Corps buys a lot of earplugs. You find them all around Camp Pendleton: under the bleachers at the firing range, in the bottoms of washing machines. They are effective, and cheap as bullets[13] (which also turn up in the washing machines). For decades, earplugs and other passive hearing protection have been the main ammunition of military hearing conservation programs. There are those who would like this to change, who believe that the cost can be a great deal higher. That an earplug can be as lethal as a bullet.
Most earplugs reduce noise by 30-some decibels. This is helpful with a steady, grinding background din—a Bradley Fighting Vehicle clattering over asphalt (130 decibels), or the thrum of a Black Hawk helicopter (106 decibels). Thirty decibels is more significant than it sounds. Every 3-decibel increase in a loud noise cuts in half the amount of time one can be exposed without risking hearing damage. An unprotected human ear can spend eight hours a day exposed to 85 decibels (freeway noise, crowded restaurant) without incurring a hearing loss. At 115 decibels (chainsaw, mosh pit), safe exposure time falls to half a minute. The 187-decibel boom of an AT4 anti-tank weapon lasts a second, but even that ultrabrief exposure would, to an unprotected ear, mean a permanent downtick in hearing.
Earplugs are less helpful when the sounds they’re dampening include a human voice yelling to get down, say, or the charging handle of an opponent’s rifle. A soldier with an average hearing loss of 30 decibels may need a waiver to go back out and do his job; depending on what that job is, he may be a danger to himself and his unit. “What are we doing when we give them a pair of foam earplugs?” says Eric Fallon, who runs a training simulation for military audiologists a few times a year at Camp Pendleton. “We’re degrading their hearing to the point where, if this were a natural hearing loss, we’d be questioning whether they’re still deployable. If that’s not insanity, I don’t know what is.”
Fallon is lecturing in a classroom at the moment, but after lunch the audiologists in attendance will experience some live-fire simulated combat. Working with the Department of Defense Hearing Center of Excellence, Fallon contracted a company, ArmorCorps, who in turn brought in a team of Marine Corps Special Operations forces, and together they’ve set up a half day of warfare scenarios. The aim being to provide the hearing professionals with a firsthand feel for the frustrations and dangers of the current approach, with the hope that they’ll become advocates for something better.
Fallon turns the class over to ArmorCorps’ Craig Blasingame, a former Marine with a wide superhero jaw and muscles so big that when he walks in front of the slide projector, entire images can be viewed on his forearm. Though it’s ten in the morning, Craig has a five o’clock shadow.
“We’re going to put you in an environment today and show you what it’s like to try to maintain a degree of auditory situational awareness while you’re wearing passive hearing protection.” Craig speaks like a bullhorn. He says this is because he lost some hearing as a Marine, but I think it’s because there’s so much strength coursing around in there that everything—whiskers, voice, the pectorals under his polo shirt—wants to burst forth in a powerful way.
Craig and Aaron Iwanciw, also a former Marine and now CEO of ArmorCorps, will shortly be taking the audiologists (and myself) outside for a listening exercise. Because we’re going to the firing range afterward, this is one of the rare listening exercises that will be done in body armor and a combat helmet. Aaron is smaller and quieter than Craig, and smells pleasantly of shampoo. He helped me put on my gear. (“I can stick my lip balm and tape recorder in these little skinny vest pockets.” “Those are for ammo.”)
Outside the building, Craig arranges us in a patrol formation. In a war zone, just walking down the road has a strategy to it. The “killing radius” of a fragmentation grenade is 15 feet. If troops walked along in a clump like tourists, a single grenade could kill the lot of them. Thus they keep fifteen to forty-five feet between each other on patrols. The more spread out they are, though, the harder it is to hear one another, especially with hearing protection in place.
Aaron is the point man, while Craig takes up the rear. We’re wearing ear cuffs similar to the ones people wear when they operate power tools. Craig sounds like someone shrank him down and put him inside a mason jar. I believe I hear him tell us to “step off right.” I interpret this as meaning we’re all supposed to clear off onto the right side of the road, so I start crossing over. “You’re on the left,” barks a teammate. He sounds sure, so I turn back and narrowly avoid being hit by a black Suburban creeping along seemingly out of nowhere. When a two-ton SUV driving on gravel can sneak up on you, that’s not good.
13
And, though you didn’t ask for it, here’s one more similarity between bullets and earplugs: Both have been used by physicians to protect their ears from screams. The