09/01/2008

Listen Up About Workplace Noise - And How It Can Affect Your Health

A pleasing sound can be music to the ears. Loud and frequent sound is noise -
and one of the most common health hazards in the workplace. Occupational noise
is a hazard that can cause permanent hearing loss as well as other health
problems.

Exposure to noise, too often, is more than just annoying and disruptive - it
can permanently damage our hearing. Occupational noise is one of the most
common health hazards in the workplace and can affect people differently,
depending on how susceptible they are.

Low or moderate noise levels that may be found in an office, school or computer
room, are most likely to cause annoyance and stress and may make it difficult
for people to talk to and hear one another. Louder, "industrial-grade" noises,
which may be found in a manufacturing facility, on a farm or even in a
cafeteria, can cause permanent hearing loss.

How loud is too loud?

Occupational exposure limits (OELs) for noise are usually given as the maximum
length of exposure permitted for various noise levels measured in decibels
(dBA). The noise exposure limits vary within the different jurisdictions.

Even without technical measurements however, certain tell-tale signs can help
you determine if your workplace has a noise problem. Do people have to raise
their voices? After a shift, do their ears ring, and do they need to play their
car radios louder than on the way to work? After working in a noisy environment
for a few years, do the employees find it hard to understand conversations at
parties, restaurants or other crowded places?

Health effects of exposure to noise

We immediately think about noise affecting our hearing but it can be blamed for
other health effects as well. Though it's difficult to pinpoint noise as the
culprit in some cases, researchers believe it may act as a general stressor and
cause some symptoms that are totally unrelated to hearing - such as changes to
blood pressure (e.g. high blood pressure) and heart rate. A noisy environment
can affect how a worker breathes and sleeps and, generally, can have a negative
effect on the worker's physical and mental health.

Hearing related health effects range from tinnitus (a ringing or buzzing in the
ear), to temporary hearing loss that may improve over time in a quiet place, to
permanent hearing loss. A person who is exposed to noise for long periods of
time or is exposed often, or at high frequencies, may experience permanent
hearing loss. Also known as permanent threshold shift, permanent hearing loss
gets worse for as long as the noise exposure continues. Noise-induced permanent
hearing loss is a cumulative process. Initially, noise-induced hearing loss is
most pronounced at a frequency of 4000 Hz, but it spreads over other
frequencies over time and as the noise level increases.

Sometimes, just one short burst of extremely loud noise such as a gun shot can
cause acoustic trauma that damages hearing.

Besides noise, other factors that affect a worker's hearing may include
vibration (e.g. from a jack hammer), the worker's age, certain medications and
diseases, and exposure to "ototoxic" chemicals, such as toluene and carbon
disulfide. Exposures to noise outside of work (e.g. recreational activities
such as playing in a rock band, skeet shooting) are also factors that
contribute to the person's overall noise exposure.

What can be done?

A noise assessment and employee survey can help determine where the noise is
coming from, how much noise there is, who is exposed and for how long. The most
obvious and effective solution to noise, of course, is to eliminate it, but
that's not always feasible in the workplace. The next best option is to control
noise at its source by lowering it to acceptable levels with engineering
controls. Administrative controls, and the use of appropriate personal hearing
protection are also used.

Engineering controls substitute or modify the noise source itself, or the
workplace environment (e.g. enclosing the noise source, using mufflers on
equipment etc). Administrative controls involve rotating work schedules, or
changing production schedules, to keep noise exposure time within acceptable
limits. Where technology cannot adequately control the problem, workers should
wear appropriate personal hearing protection such as ear muffs or plugs, but
only as an interim measure until noise is controlled at the source.

Controlling noise and preventing work-related hearing loss is essential. Once
your hearing is lost - it's gone forever. Spread the message, but not too
loudly!


More info


AplusA-online.de - Source: Canadian Centre for Occupational Health and Safety (CCOHS)