Handbook of Occupational Safety and Health, 3rd Edition

CHAPTER 9OCCUPATIONAL NOISE EXPOSURE AND HEARING CONSERVATION

CHARLES P. LICHTENWALNER

Lucent Technologies, Bell Laboratories, 600 Mountain Ave., Murray Hill, NJ, 07974

and

KEVIN MICHAEL

Michael & Associates, 246 Woodland Dr., State College, PA, 16803

9.1 INTRODUCTION

Few locations or circumstances in nature produce noise loud enough or for long enough duration to damage hearing. It remained for man, himself, to produce noises capable of causing injury. The knowledge that loud noises can produce these injuries has been known for several hundred years.

The most obvious and best quantified injury from noise is deterioration of hearing ability. However, except for extremely loud sounds, noise‐induced hearing loss is a slowly progressive debility that usually goes unnoticed by those affected until the loss is significant. There are no visible effects and usually no pain.

Hearing loss occurring naturally from aging is called presbycusis, although some have argued that much of the presbycusis seen in industrialized societies may actually be caused by ambient (non‐occupational) noise exposures (Kryter 1994). Hearing losses can also be pathological from medical abnormalities, ranging from simple, easily correctable conditions such as impacted earwax and middle ear infections to severe problems such as deafness from rubella during gestation. As in many other areas of industrial hygiene, it is difficult to determine the contribution of these various elements – (i) occupational noise exposure, ...