An occupational noise and hearing survey was made to characterize noise-exposure levels in a variety of industries, to describe the hearing status of workers exposed to such noise conditions, and to attempt to establish a relationship between occupational noise level and hearing loss that would be applicable to general industry. The four types of data collected during a typical survey at a given individual plant included noise measurements, background personal- occupational information, medical and otologic data, and audiometric data. The relationship between hearing-loss-risk and noise level has been roughly defined for employees who work eight hours a day in relatively simple, or "ordinary" noise environments. The effects of fluctuating levels, quiet rest periods, shortened exposures at higher levels, administrative controls, ear protectors, impact or impulsive noise, lengthened exposure, seasonal exposures, high frequency noise, and infrasonic noises could not be quantified without further research and evaluation. Additional work is indicated to enhance the effectiveness of audiometric monitoring and noise-measurement techniques, and to develop better indicators and citeria for hearing loss.
National Institute for Occupational Safety and Health, Public Health Service, Cincinnati, Ohio, TR 86, 58 pages, 4 references