A field evaluation of noise-induced temporary threshold shift.

Noise-induced temporary and permanent threshold shifts of 9 brewery workers were obtained by means of 6 hearing tests during two consecutive days. Subjects had been exposed 6 to 8 hours daily to a bottling noise for approximately 15 years. Results confirm that empirical rules predicting exponential growth and recovery of TTS during and following a work-day apply in men who have a significant permanent threshold shift from repeated exposures to the same work-day noise for a number of previous years.