The effects of noise on telephone operators

1. One hundred twenty-nine telephone operators were given audiograms before work and again after four hours of work exposure. Since these operators habitually use the same ear for their monaural headset, the non-listening ear served as a yoked control in examining work related effects on hearing. The hearing threshold measurements conducted on the operators in this study disclosed no statistically significant shifts in mean threshold indicating no population effect for either short-term or long-term work exposure. 2. Two thousand random hours of magnetic tape recordings of operator positions disclosed the occurrence of 36 spurious signals of 94 dB SPL or above lasting from 0.4 to 145 seconds. The maximum amplitude recorded was 109 dB SPL. These tones occurred at a rate of about one per week per operator position. 3. On 36 operators reporting 51 incidents of acoustic disturbance, audiograms were obtained about 15 minutes and again at least 16 hours following the acoustic disturbance. No significant objective effects on hearing thresholds were identified.