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 in Canada. CCOHS has more information on Occupational Exposure Limits for Workplace Noise in Canada on its website.

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!

You can find out more about workplace noise on OSH Answers.

CCOHS has more information on Occupational Exposure Limits for Workplace Noise in Canada

Learn about the e-course from CCOHS: Preventing Hearing Loss From Workplace Noise

Noise and Hearing Loss Prevention from NIOSH

A 'greedy scheming' insurance industry is plotting to deny asbestos victims their rightful compensation, according to UCATT. Alan Ritchie, the building union's general secretary, used his speech at this week's Labour Party conference to launch a renewed attack on insurers. His comments follow an insurance industry initiated High Court challenge which started in the summer, where they are arguing that the insurer at the time a person was exposed to asbestos should no longer be responsible for paying compensation. Instead the 'trigger' for compensation should be when the asbestos-related disease develops. Alan Ritchie told Labour delegates: 'Every week 40 people die of mesothelioma. It is incurable. Victims die an agonising death.

It is sickening that the insurance industry wants to block their compensation.' UCATT said that if the industry was successful with its case, then hundreds of asbestos victims would no longer receive compensation, saving itself billions in reduced claims. The UCATT motion was accepted at Labour Conference, but that does not mean it will become Labour Party policy.

UCATT news release. BBC News Online.

A Greater Manchester family has obtained £205,000 in compensation after their dad was exposed to asbestos as a teenager. The granddad-of-seven, whose name has not been released, died of the asbestos cancer mesothelioma following exposure to the dangerous dust while working during the 1950s for a company which became part of British Telecom (BT). His job at Bolton Manual Exchange involved laying telephone cables in floors and walls. His job included covering the cables with asbestos material, which protected against fire. He worked for the company for almost 40 years before taking early retirement in the 1980s.

In March 2007 he was diagnosed with mesothelioma and he died just four months later. The family's legal adviser, Steven Dickens of Thompsons Solicitors, commented: 'We are pleased we have been able to help this family to receive compensation. Mesothelioma is a terrible disease often caused by negligent employers.' He added: 'The number of people diagnosed with asbestos related illnesses is expected to rise until 2010 so it is vital that employers who caused this suffering due to negligence, and their insurers, are held to account by paying compensation to the victims and their families.'

India: 'Devastating' asbestos cancer epidemic looms

Record and rising asbestos imports to India will translate to thousands of asbestos-related cancer deaths each year and are already responsible for 'a hidden epidemic,' according to an expert report published this week. The authors say the report exposes the Indian government's collusion with asbestos stakeholders at home and abroad, and call for an immediate national ban on all asbestos use. 'India's asbestos time bomb,' published by a coalition of Asian campaign and research organisations, global union federations and the International Ban Asbestos Secretariat (IBAS), calculates that total asbestos usage in India since 1980 exceeds 6 million tonnes, matching the amount used in the UK in its entire industrial history. India is far and away the world's largest importer of asbestos.

'The UK is now in the grip of its largest ever industrial disease epidemic, with between 5,000 and 10,000 estimated to be dying of asbestos cancers every year,' commented report editor Laurie Kazan-Allen. 'India, with ineffective regulation on asbestos use, is on the verge of a much larger and more devastating epidemic.' Annual imports of asbestos to India now exceed a quarter of a million tonnes, and have climbed rapidly over the last decade. Usage accelerated after the Indian government in 2004 slashed import duty on asbestos. Laurie Kazan-Allen said 'politicians and asbestos peddlers should take heed - we aim to see the industry wither and die and its apologists face the courts for knowingly and in the name of profit pushing the world's worst ever industrial killer.'

IBAS news release. India's asbestos time bomb, September 2008