Starting this year, WorkSafeBC (WSBC) will begin investigating an aspect of workplace noise that has so far been heard from only rarely.
"WorkSafe has identified the non-auditory effects of workplace noise on workers' health as something that needs to be investigated," said Colin Murray, senior manager of the Risk Analysis Unit. "It's definitely on our radar for this year."
Until now, WorkSafeBC has focused its attention on the auditory effects of long-term exposure to workplace noise. Between 40,000 and 50,000 construction workers have their hearing tested every year by mobile testers approved by WSBC. The non-auditory effects of workplace noise, however, are not as well known.
"Noise is a generalized stressor that can cause a lot of different unwanted effects other than hearing loss," said Hugh Davies, associate professor in the University of British Columbia's (UBC) School of Population and Public Health. "Noise causes stress which, if chronic over long periods of time, is associated with all kinds of illness." Davies said one noise-caused illness that has been studied is cardiovascular disease.
"But, there is also evidence for metabolic diseases, such as diabetes, adverse birth outcomes, in addition to annoyance and stress," he said. Davies said he hasn't done any direct research on the effects of noise on workers' health in the construction industry in western Canada.
"Much of the work on noise and non-auditory effects is from the research on traffic noise, so it's not directly comparable," Davies said. "But, there is evidence from studies in manufacturing – including sawmills here in BC – that have shown a link."
In a study that was published in the scholarly journal Epidemiology, Davies and four co-authors looked at a group of 27,464 workers who had worked for at least one year between 1950 and 1995 at 14 lumber mills in British Columbia and who were followed up over the same period. Davies and the other researchers assessed the total amount of noise to which the workers had been exposed.
They concluded that chronic exposure to noise levels typical of lumber mills and similar workplaces was associated with excess risk of death from heart attacks.
"Given the very high prevalence of excess noise exposure at work, this association deserves further attention," they wrote. "The health impact of chronic exposure to very high levels of noise may be significant." There are many potential sources of loud noise on a construction work site, said Richard Dulong, safety and injury management advisor at the B.C. Construction Safety Alliance.
"Construction sites are absolutely noisier than more conventional places of work, such as offices.," he said.
"A few of the more common sources of loud noise are motor vehicles of various kinds, mobile equipment and power tools, as well as ambient street noise."
In B.C., an employer must ensure that a worker is not exposed to noise levels above either 85 decibels (dB) of daily noise exposure level or 140 dB peak sound level. An informal rule of thumb is that if you have to shout to make yourself heard to someone an arm's length away from you, your work environment is too loud. If noise in the workplace exceeds either of these exposure limits, the employer must develop and implement a noise control and hearing conservation program.
Murray Hodgson, a professor in the School of Population and Public Health at UBC, said there are three common, but often overlooked, ways in which workplace noise can be reduced.
"One way is to reduce noise at the source, so that less noise is generated outward," he said. "A second way is block or absorb noise as it travels. And, the third is to protect the person receiving the noise with hearing protection of some kind, such as ear plugs or ear muffs."