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Health and Safety: Protect your hearing

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 setting are most likely to cause annoyance and stress and may make it difficult for people to talk to and hear one another or to talk to a customer. Louder, “industrial-grade” noises, which may be found in a manufacturing facility, used by landscapers using machinery, or used on a farm, 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 in Canada. CCOHS has more information on Occupational Exposure Limits for Workplace Noise in Canada on its website.

Even without technical measurements, however, certain telltale 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 also affect how a worker sleeps and 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, is exposed often, or exposed to high frequencies may experience permanent hearing loss. Permanent hearing loss gets worse for as long as the noise exposure continues. Sometimes, just one short burst of extremely loud noise such as a gunshot can cause acoustic trauma that damages hearing. However, noise-induced permanent hearing loss is most often a cumulative process. Also known as permanent threshold shift, initially, noise-induced hearing loss is most pronounced at a frequency of 4,000 Hz, but it spreads over other frequencies over time and as the noise level increases.

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 an 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 to keep noise exposure time within acceptable limits. Where technology cannot adequately control the problem, workers should wear appropriate personal hearing protection such as earmuffs or plugs, but ideally 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.

The Canadian Centre for Occupational Health and Safety (CCOHS) promotes the total well being of workers in Canada by providing information, training, education,  systems and solutions that support health and safety programs and injury and illness prevention.
www.ccohs.ca