NEW YORK - Extremely loud noise on the job, as well as hearing loss from noise exposure, may cause workers to miss danger warnings, a Canadian study suggests.
They found that workers regularly exposed to noise levels of 100 decibels - about the volume standing next to a lawnmower - had more than doubled risk of being hospitalized for a workplace injury. Workers with hearing loss were also more likely to be seriously hurt.
"Noise induced hearing loss is a public health issue - in the USA, up to 30 million workers are exposed to noise and in Quebec this number is estimated to be 400,000," Serge-Andre Girard told Reuters Health by email.
Girard, who led the new study, is a researcher with the National Public Health Institute of Quebec in Quebec City.
"Despite considerable energy devoted to the prevention of noise-induced hearing loss, it remains a significant problem," Girard said. "From an occupational safety perspective, work-related injuries remain an important issue that generates significant costs for businesses, workers and compensation organisations."
The US National Institute for Occupational Safety and Health suggests that companies undergo prevention programs for all workplaces with hazardous levels of noise, including noise assessments, noise control, monitoring of workers' hearing, appropriate use of hearing protectors and worker education about protecting themselves from noise.
Girard said that exposure to high noise levels increases fatigue, decreases the ability to concentrate and impairs the quality of communication between workers. Both noise and noise-induced hearing loss could be involved in the occurrence of accidents, he added.
Girard and his colleagues looked at records for 46,550 male workers over nearly 20 years, and found that 1,670 had been hospitalized for work-related injuries within 5 years of being given hearing tests.
The researchers compared the number of injuries to workers' levels of hearing loss indicated by the tests and their exposure to loud noises in the workplace.
They found that for every decibel of hearing loss, the risk of hospitalization due to work-related injury increased by 1 per cent.
The researchers also found that workers exposed to noise levels above 100 decibels had 2.4 times the risk of being hospitalized for work-related injuries compared to workers not exposed to loud noise.
In their report in the journal Injury Prevention, Girard's team estimates that for workers with the combination of severe hearing loss and working in an environment where noise exposure is overly intense the risk of being hospitalized with a work-related injury is 3.6 times that of workers with neither factor.
"Companies have always had a reason to control noise to protect the workers' hearing but this kind of evidence gives companies and workplaces another major reason to control noise, which is to make the workplace safer as well," Dr. Peter Rabinowitz told Reuters Health.
A researcher for the department of Environmental and Occupational Health Sciences at the University of Washington in Seattle, Rabinowitz was not involved in the study.
Workers who can't hear properly, either because of hearing loss or wearing hearing protection that's too strong, might miss important communications and signals on the job, he said.
But one thing that might help is if workers and supervisors devise special safety signals that don't rely as much on hearing.
"You can have visual signals for safety and other ways to make the workplace safer and not make everything rely on hearing and you can also find special types of hearing protection or other assistive devices that help a person who has hearing loss function well in a noisy situation," Rabinowitz said.
But it's important to make sure workers are wearing the right kind of hearing protection, he added.
"Believe it or not, sometimes they could be getting too much protection from the earplugs, which can make communication even more difficult," he said.
Rabinowitz also said that while this new study adds to the evidence on injury risk in an environment with extremely loud noise, more research is needed to also assess that risk at lower levels of noise.
"I think we need to do more research (on) noise that's a little more common and slightly less, say between 80 and 90 decibels, and find out more about how that can affect injury," he said.