Hearing conservation in industry.

Noise-induced hearing loss is a major and entirely preventable public health problem. Effective prevention of this disorder has yet to be achieved in the United States but would improve the overall hearing health of the population more than the treatment of all other otologic disorders combined. Losses that are mild to moderately severe and maximal at 3, 4 or 6 kHz are typical but not pathognomonic. Individual differences in susceptibility are substantial but unpredictable. Hearing conservation programs are now required by the Occupational Safety and Health Administration for almost all employees whose daily exposure to noise exceeds a time-weighted average of 85 dBA (A-weighted sound pressure level). The permitted exposure level is 90 dBA time-weighted average, above which engineering or administrative controls or hearing protectors are required. Workers with lesser exposures (85 to 90 dBA time-weighted average) who have hearing changes must be similarly protected. Many, but not all, elements of required hearing conservation programs have been specified recently by the Occupational Safety and Health Administration. Medical supervision and otologic referral are important components of hearing conservation programs because otologic problems other than noise-induced hearing loss are common in industrial populations. Compensation for noise-induced hearing loss, which is awarded through state workers' compensation boards, as well as certain federal sources, varies widely.