CCOHS Safety Tips: When loud is too loud

Earmuffs protect workers from excessive noise. PHOTO:THINKSTOCK

Low or moderate noise levels in an office may be annoying, but louder “industrial-grade” noises in a manufacturing facility can cause permanent hearing loss.

Occupational exposure limits are measured in decibels but the limits vary within different jurisdictions (see www.ccohs.ca, Occupational Exposure Limits for Workplace Noise in Canada). However, there are other tell-tale signs that indicate noise is a problem:

• Do people have to raise their voices?
• After a shift, do their ears ring?
• Do they need to play car radios louder after work?
• Do they find it hard to understand conversations in crowded places?

Hearing related health effects range from tinnitus (a ringing or buzzing in the ear) and temporary hearing loss, to permanent hearing loss, a cumulative process, and most pronounced at a frequency of 4,000 Hz.

Other factors that affect a worker’s hearing include vibration, the worker’s age, certain medications and diseases, exposure to “ototoxic” chemicals, such as toluene and carbon disulfide, and exposure to noise outside of work.

An assessment and employee survey will help determine where the noise is coming from, how much there is, who is exposed and for how long. When it’s not possible to eliminate the noise entirely, the next best option is lowering it to an acceptable level at the source with engineering controls.

Administrative controls involve rotating work schedules, or changing production schedules, to keep exposure time within acceptable limits.

And where technology can’t eliminate the problem, workers should wear appropriate personal hearing protection such as earmuffs or plugs – as an interim measure until other measures control the noise at the source.

This article was provided by the Canadian Centre for Occupational Health and Safety (CCOHS). The not-for-profit federal corporation promotes the physical, psychosocial and mental health of Canadian workers by providing information, training, education and management systems. It appears in the April 2015 issue of PLANT.