Many of us are unaware of the high noise levels to which we are frequently exposed and the permanent hearing damage that may result. I learned this the hard way.

For 16 years I have been working in hvacr, primarily on residential and small commercial refrigeration, air conditioning, and heating systems.

Much of the equipment does not exceed the 80 to 90 decibel limit at which hearing damage occurs. However, much does: especially larger compressors and fans. Also, many tools exceed this level, i.e., hammer drills, wet/dry vacuums, heatguns, torches, nitrogen blowguns, and refrigerant recovery machines.

To identify for yourself which noises will cause hearing loss, there is a rule of thumb. Any noise which prevents you from easily hearing a person speaking next to you in a normal conversational voice is too loud. This is referred to as toxic noise.

I was not aware that I had suffered severe permanent nerve damage in both ears from noise exposure until four years ago, when it was revealed at an annual physical examination. I had believed I heard normally since all lower-frequency sounds (most conversational tones) were unaffected.

The damage caused by noise is irreversible, but is easily and inexpensively prevented. Now I carry earmuff protectors ($15) in my service bucket onto every job. Earmuffs are quick to put on for short-term noise exposure and foam earplugs (25 cents per pair) are ideal for long-term noise exposure. These will prevent further hearing damage.

Hearing-aid technology may not yet be frequency-specific enough to help with many cases of noise-induced hearing loss. But knowing you have suffered hearing loss will make you vigilant about protecting your hearing from further damage and learning ways to compensate for your disability.

Toxic noise is becoming a major issue in this country, and public awareness is increasing. The Deafness Research Foundation has a national campaign to force legislation to reduce toxic noise. They hope that noise reduction will be taken as seriously as smoking and asbestos.

All technicians who are exposed to toxic noise should have a family physician test their hearing at an annual checkup.

If you have suffered hearing loss, tell your own story. The more that toxic noise is discussed, the more technicians will take heed and remember to protect their hearing. We must help our coworkers understand how fragile our wonderful gift of hearing is.

Further information on noise-induced hearing loss and free earplugs can be obtained from the Deafness Research Foundation at 202-289-5850; 202-682-0356 (fax); www.drf.org (website).