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Friday, September 1, 2006

The Silence That Suffocates

Aircraft mechanics and troops returning from combat in Iraq and Afghanistan have one thing in common: potential and long-term hearing loss. I write from experience, having served in Vietnam combat and as a Marine Corps artillery officer for years afterward.

For veterans of the current wars, they are returning with permanent hearing damage from explosions, weapons firing, and so forth. For aircraft mechanics, airports and hangars can be very noisy places. The noise is often at a level that will not encourage action to protect hearing, yet the noise will cause damage through longer term exposure on a daily basis. Military personnel can be financially compensated for service-related hearing loss, but civilian ground crews most likely will not, despite the fact that a noisy work environment - particularly working around jet engines - will rob them of hearing in later life.

Employers have been proven in court to have nil or negligible liability for damage to one's hearing. There is a bit of irony here, in that aircraft maintainers are often required to wear hard-hats, but not necessarily hearing protection.

Excessive noise, especially of the jet turbine variety, causes damage to hearing that is permanent, and cannot be fixed or cured. Exposure time per day, and exposure day after day, is a vital key to the extent of hearing degradation.

The loss takes the form of tinnitus, or a chronic ringing in the ears (also a symptom, for those of us in middle age, of high blood pressure). It is often referred to as "head noise." Tinnitus has many causes, including aging and medications, such as aspirin, quinine and various anti-inflammatory potions, but more typically it is due to acoustic trauma - an explosion or a screaming jet engine.

Tinnitus will worsen with age, and in its chronic (loud) form can distract from mental concentration and interfere with sleep. If one is a soldier at the front, hearing loss and tinnitus may be viewed as an occupational hazard. If one is working in an aviation environment, particularly on the line, it is an occupational hazard, although one that need not cause injury.

Long-term and chronic exposure to industrial noise leads to deafness. The damage is cumulative, insidious and permanent. For the soldier, a hearing impediment will qualify for treatment (hearing aids) and/or palliative devices for masking the aural buzzing. Recognition of an aviation technician's cumulative hearing loss and tinnitus might be another matter altogether.

In excess of a quarter of the troops returning from Iraq since March 2003 have exhibited marked hearing loss and have complained of tinnitus. The simplest form of protection is earplugs. According to the December 2005 issue of the American Journal of Audiology, "There were not adequate supplies of earplugs to equip all deploying soldiers" prior to the invasion of Iraq. Many troops have resisted wearing them for fear of missing critical commands or not hearing enemy movement. The U.S. Army and the Marine Corps have now distributed thousands of pairs of an innovative device designed to overcome that reluctance, the Combat Arms Earplug. It blocks hazardous noise levels while allowing nearly normal hearing, which is to say of conversational speech.

Hearing conversation is a very individual safety protocol. In the military chain of command, discipline will normally ensure that all subordinates will use hearing protection without supervision. In the civilian context, one may be picked up by the "tarmac police" for not wearing a dayglo vest on the ramp or for not displaying a security badge, but it is not likely that one's ears will be examined for evidence that ear protection is being worn for the battle against noise.

A maintenance technician acting in such a cavalier manner could likely "get away with" the absence of hearing protection for years. Like chronic cigarette smoking, however, eventually there is a price to be paid. That will probably come as a shock to the aviation mechanic diagnosed as needing a hearing aid. One thing is clear, it's critical that hearing protection be worn. Without such protection, the ultimate non-sound of perpetual silence is almost guaranteed.

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