Abstract
A study of audiometric data indicates that for long-term exposure to industrial noise of approximately 90 dB octave-band SPL: (1) Most hearing level changes at 3000, 4000, and 6000 cps occur in the initial 15 years, whereas at 500, 1000, and 2000 cps, hearing level change is approximately linear with exposure time. (2) Large individual differences in the amount of hearing level change are evident; these differences increase with audiometric frequency. (3) Men have greater hearing level changes than women. (4) Hearing level changes produced by noise-exposure and by aging May not be differentiable.