NOISE EXPOSURE ASSOCIATED WITH HEARING-AID USE IN INDUSTRY

Although noise may be innocuous in many vocational environments, there is a growing concern in industry that it can reach hazardous levels w hen amplified by hearing aids. This study examined the daily noise exp osures associated with hearing aid use in industry. This was done by b oth laboratory and site measurements in which hearing aids were couple d to the microphone of an integrating sound level meter or dosimeter. The former method involved the use of recorded railroad and manufactur ing noise and a Bruel and Kjaer 4128 Head and Torso simulator. In the latter procedure, a worker wore one of three hearing aids coupled to a dosimeter during 8-hour shifts in a manufacturing plant. Both methods demonstrated that even when amplified by mild-gain hearing aids, nois e exposures rose from time-weighted averages near 80 dBA to well above the OSHA maximum of 90 dBA. The OSHA maximum was also exceeded when m oderate and high gain instruments were worn in non-occupational listen ing environments. The results suggest that current OSHA regulations th at limit noise exposure in sound field are inappropriate for hearing a id users.