Costs and effectiveness of hearing conservation programs at 14 US metal manufacturing facilities

Abstract

Objective: This study characterised overall and specific costs associated with hearing conservation programmes (HCPs) at US metal manufacturing sites, and examined the association between these costs and several noise-induced hearing loss (NIHL) outcomes. Design: We interviewed personnel and reviewed records at participating facilities. We also measured noise for comparison to the ten-year average of measurements made by each facility. NIHL outcomes assessed included rates of standard threshold shifts (STS) and high-frequency hearing loss, as well as prevalence of hearing impairment, for each participating facility. We used linear regression to identify per-person HCP costs that best predicted the NIHL outcomes. Study sample: We evaluated 14 US metal manufacturing facilities operated by a single company. Results: Annual HCP costs ranged from roughly $67,000 to $397,000 (average $308 ± 80 per worker). Our full-shift noise measurements (mean 83.1 dBA) showed good agreement with the facilities’ measurements (mean 82.6 dBA). Hearing impairment prevalence was about 15% overall. Higher expenditures for training and hearing protector fit-testing were significantly associated with reduced STS prevalence. Higher training expenditures were also related to lower hearing impairment prevalence and high-frequency hearing loss rates. Conclusions: HCP costs were substantial and variable. Increased workplace spending on training and fit-testing may help minimise NIHL.

Key Words:

• Noise
• hearing conservation/hearing loss prevention
• psychoacoustics/hearing science
• medical audiology

Acknowledgements

The authors wish to thank the participating worksites, without whose support this research would not have been possible.

Declaration of interest: No potential conflict of interest was reported by the authors.

This research was funded by grants from the National Institute for Occupational Health and Safety (Assessing hearing conservation effectiveness, 1 R01 OH010132-01), National Institute on Aging (Disease, Disability and Death in an Aging Workforce, NIH/NIA, 1 R01 AG026291-06), and a contract with Alcoa Inc. At the time of the site visits, LFC received a portion of her compensation at Yale through a long-standing contractual agreement with Alcoa, Inc.