professional to take some noise readings. When he gave me the
noise levels, he commented that I was “trying to find an overexposure.” But that was not my intent—I wanted to determine the
exposures and then institute appropriate controls.
The American National Standard for Hearing Loss Prevention
for Construction and Demolition Workers (ANSI/ASSE A10.46-
2007) recognizes that hearing protection is very difficult in a
construction area. The standard states that when workers are
exposed to sound levels at or above 85 dBA, controls should be
put in place to reduce sound levels to below 85 dBA. If those
controls fail to reduce exposure levels below 85 dBA or are
not feasible, employees should be provided hearing protection
devices. Workers exposed to noise exceeding 105 dBA should
wear double hearing protection, which adds about 5 dB of attenuation to the protector with the higher noise reduction rating (NRR). However, if a fit-test of user attenuation measures
proper protection with a single protector, double protection
may be disregarded.1
This requirement is independent of a time-weighted average exposure because noise exposures in a construction area
change constantly and are impossible to define. To protect
workers from noise in these areas, hearing protection is always
New Noise Research
Recent research shows that noise is more hazardous than previously thought. In studies of laboratory guinea pigs,2 researchers
found that exposure to high-decibel impact noise left lasting
effects on the cochlear nerves independent of the measured
threshold shift in hearing. This could explain the basis for tinnitus and other disorders of the ear, such as the inability to
understand speech in a noisy environment. This loss of understanding does not affect the ability to detect sounds and is
therefore not detectable using standard audiograms.
According to Dr. Sharon Kujawa, in a study published in The
Journal of Neuroscience, exposure to noise is “more dangerous”
than current exposure guidelines seem to take into account:
[N]ormal threshold sensitivity can mask ongoing and dramatic
neural degeneration in noise-exposed ears.… Federal exposure
guidelines … aim to protect against permanent threshold
shifts, an approach that assumes that reversible threshold
shifts are associated with benign levels of exposure.… The
present results contradict these fundamental assumptions.
Figure 2. Fit-testing for hearing protection is now an easy process. It compares ambient noise outside the ear with the noise
inside the ear.
Thus, new scientific insights demand that we reassess the use
of audiometric exams as a basis for all determinations on the
effects of occupational noise.
What We Still Don’t Know
We are still learning just how much we don’t know about
noise exposure in the workplace. For instance, we don’t know
whether our hearing protection devices effectively protect
workers. Last summer, a nationally known manufacturer of ear
plugs conducted a fit-testing demonstration at my workplace
(see Figure 2). One employee tried a plug with an NRR of 25
dBA. Testing showed that he was getting a reduction of only 3
to 7 dBA, as if he were not wearing hearing protection at all.
We found out that he had very large ear canals and could not
use standard-sized ear plugs. He uses earmuffs now instead.
Hearing protection is not a cure-all. We know that substitution and elimination are the best control methods. NIOSH is de-
At AIHce 2012, attendees will find several PDCs and technical sessions focusing on noise hazards. In addition, two special events are
geared toward building an advanced understanding of noise exposures both on and off the job.
The 85/3 Coalition is a brand-new group dedicated to recognizing organizations and employers that have adopted 85 dBA for an 8-hour
noise exposure limit measured with a 3 dB exchange rate for their hearing loss prevention programs. The 85/3 Coalition encourages others to adopt this hearing protection strategy. A session on the 85/3 concept will be held at AIHce on Monday, June 18. For more information on the 85/3 Coalition, e-mail email@example.com.
Dangerous Decibels Workshop
Dangerous Decibels is a public health campaign focused on hearing loss prevention intervention, especially for children. According to
the 3rd National Health and Nutrition Examination Survey, “ 5.2 million 6- to 19-year-olds have hearing loss directly related to noise exposure.”
3 In response to this information, Oregon Health & Science University, Portland State University and University of Northern Colorado
are leading the Dangerous Decibels Educator Training Workshop June 19–20 at AIHce. Interested individuals can learn how to deliver a
50-minute classroom program demonstrated to change knowledge, attitudes and behaviors in elementary school students regarding sound
exposure and the use of hearing protection strategies.
Noise Events at AIHce 2012