Noise exposure and hearing loss prevention programmes after 20 years of regulations in the United States

Abstract

Objectives: To evaluate noise exposures and hearing loss prevention efforts in industries with relatively high rates of workers' compensation claims for hearing loss. Methods: Washington State workers' compensation records were used to identify up to 10 companies in each of eight industries. Each company (n = 76) was evaluated by a management interview, employee personal noise dosimetry (n = 983), and employee interviews (n = 1557). Results: Full-shift average exposures were ≥85 dBA for 50% of monitored employees, using Occupational Safety and Health Administration (OSHA) parameters with a 5 dB exchange rate (Lave), but 74% were ≥85 dBA using a 3 dB exchange rate (L eq). Only 14% had Lave ≥90 dBA, but 42% had L eq ≥90 dBA. Most companies conducted noise measurements, but most kept no records, and consideration of noise controls was low in all industries. Hearing loss prevention programmes were commonly incomplete. Management interview scores (higher score = more complete programme) showed significant associations with percentage of employees having Lave ≥85 dBA and presence of a union (multiple linear regression; R2 = 0.24). Overall, 62% of interviewed employees reported always using hearing protection when exposed. Protector use showed significant associations with percentage of employees specifically required to use protection, management score, and average employee time spent ≥95 dBA (R2 = 0.65). Conclusions: The findings raise serious concerns about the adequacy of prevention, regulation, and enforcement strategies in the United States. The percentage of workers with excessive exposure was 1.5-3 times higher using a 3 dB exchange rate instead of the OSHA specified 5 dB exchange rate. Most companies gave limited or no attention to noise controls and relied primarily on hearing protection to prevent hearing loss; yet 38% of employees did not use protectors routinely. Protector use was highest when hearing loss prevention programmes were most complete, indicating that under-use of protection was, in some substantial part, attributable to incomplete or inadequate company efforts.