Occupational noise regulations. How good can they be?

Abstract

Ideally, occupational noise regulations would provide all workers with protection from any measurable degradation of hearing acuity. Practically speaking, most present occupational noise regulations are set at levels that primarily protect hearing in the speech frequency range. Consequently, if the regulation is enforced, workers are prevented from becoming so deaf that they are a burden to society. This is true whether the limit is 90 or 85 dBA and whether 3‐ or 5‐dB time trading relations are used. There has been much discussion over the appropriate limits to set in occupational noise regulations. However a close examination of the facts on which these limits are based makes the actual limit seem less important. This paper examines these facts which include:—the scatter in the internationally accepted data base and its effect on the accuracy of the 0‐dB hearing level; the large apparent variation in individuals susceptibility; the difficulty in assessing the effects of sociocusis; the accuracy of the audiometric test (test conditions and the test itself); and the question of how best to measure occupational noise levels. The need for continuing research to develop better methods of hearing measurement and the development of new data bases relating noise exposure, age, and hearing loss, is elaborated. It is concluded that limits must be set and enforced, and workers educated, to reduce occupational noise‐induced hearing loss.