OCCUPATIONAL NOISE-INDUCED HEARING-LOSS SURVEILLANCE IN MICHIGAN

Occupational noise-induced hearing loss (NIHL) is nit important yet of ten overlooked illness that can affect an individual's safety and perf ormance at work. This article describes a state-based surveillance sys tem for occupational NIHL. The Michigan surveillance system enables us to describe the magnitude of occupational NIHL among Michigan workers and direct public health interventions in the form of enforcement wor kplace inspections. The data presented are based on interviews of indi viduals with occupational NIHL reported to the Michigan Department of Consumer and Industry Services (MDCIS) by Michigan's audiologists and otolaryngologists from 1992-1997. From 1992-1997 1378 individuals with occupational NIHL were reported to the MDCIS and interviewed about th eir exposures to noise at work. Over 70% of the workplace noise exposu res were in manufacturing. At the most recent company where these indi viduals were exposed to noise, approximately 46% were not provided reg ular hearing testing. Regular hearing testing was more likely to occur in the larger companies and in industries covered by regulations requ iring such testing to be performed. There were improvements over time in the percentages of companies providing regular hearing testing and hearing protection. Construction workers are employees among a group o f industries that are not adequately protected from excessive noise ex posures by occupational regulations. Regular hearing testing was not p rovided for over 96% of construction jobs, although hearing protection such as earplugs or earmuffs was provided for approximately half of t hese jobs. Forty-three state enforcement inspections were conducted at the companies reported by the patients interviewed, because these com panies were reported to provide no regular hearing testing or no heari ng protection despite exposures to excessive levels of noise. During t he 43 inspections, 23 companies had noise levels above 85 dBA, and 17 of those had either no hearing conservation program (HCP) or had one t hat was cited as being incomplete. The inspections potentially protect ed 758 similarly exposed workers in the companies with the high noise levels that lacked an HCP or that had a deficient HCP. The number of p atients with occupational NIHL is likely a gross underestimate of the true magnitude of the disease. However, the surveillance system has id entified workplaces with hazardous levels of noise and no HCP, thereby protecting similarly exposed coworkers of the index patients from fur ther exposures to noise and hearing loss.