COLORADO SPRINGS, Colo. - Staff Sgt. Chris Mountjoy couldn't hear for three days after the mortar round screamed into his camp and exploded 15 feet from him. The open door of a Humvee saved him from the shrapnel, but a shock wave blew him 30 feet into a wall, perforating his ear drums.

His hearing came back, but only partially.

Now, more than two years later, the 27-year-old who loved being in the infantry spends his days behind a desk at the 10th Combat Support Hospital in Fort Carson, Colorado, where he was reassigned because of his hearing loss and a traumatic brain injury from the blast. Hearing aids help him, but they're not perfect. He seldom lets his two young children play in a different room because he cannot hear if something were to happen. He avoids loud restaurants, where background noise blots out dinner conversation with his wife.

Mountjoy isn't alone in his quiet world. A cacophony of roadside bombs, machine guns and heavy equipment is wreaking havoc on the hearing of Soldiers serving in Iraq and Afghanistan.