Prolonged exposure to excessive noise in the workplace can cause hearing loss. Noise induced-hearing loss is a major occupational health and safety issue, especially in industries such as construction, manufacturing, mining.
As the employer, it is your duty to take all reasonable steps to provide a safe workplace for your staff. If your employees are exposed to hazardous noise levels at work, you must take appropriate measures to prevent work-related hearing loss.
How does excessive noise damage hearing?
Excessively loud noise can damage the cells in our inner ear. These tiny hair cells in the cochlea help us convert sound vibrations into electric signals that the brain then interprets as sounds.
Long-term exposure to loud noise can cause irreparable damage to these cells. About 30% to 50% of these cells may be destroyed before your hearing loss can be detected through a hearing test. Hearing once lost cannot be restored. Besides these cells, loud noise can also damage the auditory nerve that carries sound signals to your brain.
How much noise is too much? What does the law say?
Occupational Exposure Limits (OELs) set down a worker’s maximum permitted daily exposure to noise without hearing protection. These are determined based on how loud the noise is (measured in decibels) and the duration of exposure to that noise (measured in hours per day).
There are two main factors affecting OELs: the criterion level and the exchange rate.
The criterion level (Lc) is the steady noise level allowed for a full eight-hour work shift. This is 85 dBA in most jurisdictions, including Alberta, British Columbia, and Ontario.
When the noise level increases above the criterion level, Lc, the permitted exposure time must be decreased. The allowed maximum exposure time is calculated using an exchange rate. The exchange rate is the amount by which the permitted sound level may go up if the exposure time is cut by half.
Employers in Alberta, British Columbia, and Ontario must ensure that workers are not exposed to noise that exceeds the OELs and 85dBA Lc.
What should I do if the workplace noise levels exceed the permissible limit?
The Occupational Health and Safety legislations in these provinces state that in cases where noise levels in the workplace exceed permissible limits, employers must implement:
- A Noise Management Program (Alberta)
- A Hearing Loss Prevention Program (British Columbia)
- Protective measures to reduce workers’ exposure to noise (Ontario)
What steps can be taken to reduce the risks?
The prevention programs across the three provinces recommend the following:
1. Managing noise exposure by implementing safety controls in the workplace in the order of their effectiveness:
The best safety control is eliminating the hazard or substituting it with a safer alternative. In this case, that would be a quieter equipment or less noisy process of work. If that is not possible, use engineering controls to reduce noise levels.
These involve making physical modifications to the workspace, equipment, and processes to reduce exposure or control the hazard.
For example, you could modify the way (lower speed, improve lubrication, etc.) the noisy equipment operates so that it makes less noise. Or place sound-absorbent material around noisy equipment. You could also separate noisy areas with sound barriers or relocate equipment in an enclosed room.
These controls aim to reduce workers’ exposure to noise by altering work policies and practices. For example, reducing shift lengths, rotating work schedules, posting warning signs, scheduling annual hearing tests and awareness training.
Personal protective equipment
You must ensure the hearing protection devices (HPDs) used to protect workers against excessive noise are appropriate and effective for the intended use. To select the right kind of HPDs, you must understand the physical characteristics of the noise exposure at the workplace, and the features and limitations of selected HPDs. It is also very important that your staff knows how to properly use and maintain their HPDs. This includes training on care and use of HPDs.
2. Educating workers
You should educate your staff on how noise-induced hearing loss occurs and how they can protect themselves.
3. Measuring and monitoring sound levels
Doing so identifies the sources of excessive noise and the staff exposed to noise exceeding the permissible limit.
4. Posting warning signs
You must post warning signs where the noise level exceeds 85 dBA. The sign must say that a noise hazard exists, and that hearing protection must be worn by all workers in that area.
5. Using hearing protection devices
As the employer, you must provide personal protective equipment to your staff. You should make sure the PPE used is appropriate to their roles, and the equipment they use.
6. Conducting hearing tests
You must conduct annual hearing tests for all employees who are exposed to noise. This would help you detect early signs of noise-induced hearing loss and keep track of ongoing changes in hearing ability.
7. Reviewing your program
You must evaluate your prevention program and protective controls in place once a year. This will help ensure your program is effective in protecting your staff.
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