Some notes on the effects of excessive noise on the hearing of a group of workers.

The data for the present investigation were collected between August, 1951, and August, 1956, in the Butterley Company's works at Codnor Park. In some of the shops of these works the noise is so intense that outsiders experience it as unpleasant and in some spots even as unbearable. During the period mentioned no protective devices were in use, largely because the workers found many of the existing protectors both uncomfortable and otherwise inconvenient. The availability of audiometric records of workers who had been exposed to noise for periods from one year to seven years made possible a first attempt to relate deterioration in hearing to prolonged exposure to intense intermittent noise. That such deterioration (based on permanent and irreversible changes in the auditory organs) occurs is well known. But the relationship between length of exposure and loss is somewhat complicated by the fact that a certain amount of loss is brought about by the natural process of ageing (presbycusis).