Daily Exposure Monitoring to Prevent Hearing Loss

Despite the existence of an OSHA standard for hearing conservation, noise-induced hearing
loss continues to be one of the most prevalent occupational conditions. Furthermore, hearing
loss rates appear to vary significantly between industrial locations with similar measured
noise exposure levels. The factors that determine an effective hearing conservation program
remain poorly understood. The effective use of hearing protection, believed to be a critical
component of such programs, is felt to be highly variable in real world situations.
Provocative new data by our research group indicate that much of the preventable hearing
loss in a large industrial workforce is occurring not among the workers in the highest
ambient noise areas, but instead among employees working in areas where measured ambient
median noise exposures are close to or even slightly below the current OSHA action level
(85dBA for an 8 hour time weighted average). One possible reason could be that the use of
hearing protection is currently less effective in such areas of lower or intermittent noise
compared to high noise areas. Since in many worksites, the majority of workers are exposed
to moderate noise levels, there is an urgent need to better understand how to prevent
hearing loss in these settings. There are also currently no national guidelines for ensuring
correct fit and function of hearing protection, and there is an urgent need to find ways to
promote the correct use of hearing protective devices. This study will assess the impact of
hearing protector fit testing and daily noise exposure monitoring, with major implications
for hearing conservation practice, and the wider prevention of noise-induced hearing loss.
It will also explore the role of hearing protective devices in areas of median noise
exposure less than 85dBA.

This proposed study is a worksite intervention trial of a new technology to reduce
occupational noise-induced hearing loss. The intervention will test the effectiveness of a
noise exposure dosimeter, the QuietDose - essentially a small microphone connected to a
noise logging device about the size of a beeper- that measures a worker's daily noise
"dose", as well as peak noise exposure, inside of the worker's hearing protectors. Workers
and the study coordinator receive daily feedback about noise exposures (if the device was
used outside of the study it would be safety personnel that received the feedback outside of
the workers themselves). Such feedback will allow steps to be taken to minimize such
exposures, such as behavioral adjustments and improved awarenessThe goal of this study is to
determine whether daily assessment and feedback of workers' noise exposures leads to more
effective use of hearing protection and prevention of noise-induced hearing loss. The
proposed study will take advantage of the unique working relationship between a research
institution (the Yale Occupational and Environmental Medicine Program) and a major
industrial corporation (Alcoa, Inc.) to conduct this intervention trial at several of the
company's facilities.

Inclusion Criteria:

The only criterion for inclusion is that the employee is currently working in an area
where there is sufficient noise exposure that the company's policy requires the use of
hearing protection.

Exclusion Criteria:

There are no exclusion criteria.