MSDs often a neglected hazard at work

Repetitive action, forceful exertion and awkward position are the leading causes

Day after day, week after week, an employee stares at a computer monitor that sits several inches higher than eye level. Does this sound like a workplace hazard? Likely not when compared to sharp tools, heavy equipment or loud noise.

Musculoskeletal disorders (MSDs) caused by injuries or disorders of the muscles, tendons, nerves and bones are responsible for almost one-half (43 per cent) of all lost-time injuries in Ontario. The price? 1.2 million working days lost and, in 2008, more than $330 million in Workplace Safety and Insurance Board costs for employers.

MSDs were the focus of a recent two-month safety blitz in Ontario. Hundreds of inspectors visited thousands of work sites in construction, health care and industrial and mining sectors looking specifically for MSD risks.

“Because these risks don’t jump out at you, we needed a focused approach,” said provincial ergonomist Anne Duffy. Employers and inspectors are often aware of acute or dangerous situations, but not as alert to the long-term risks of MSDs, she said.

So, what makes a computer monitor a musculoskeletal disorders workplace hazard?

It starts with the neck, which has to strain itself if the monitor is not at eye level.

The muscles in the neck are stretched, so the blood supply to the muscles is affected because the vessels are also being stretched. Lactic acid builds up, causing pain and, at the same time, because the neck is flexed it may also be causing nerve damage.

Duffy said over time the pain may become so severe it’s debilitating and difficult to reverse. “Anytime you get your body out of line, you could be doing damage.” 

Common MSDs include back pain, muscle strain, tendonitis, carpal tunnel syndrome and tennis elbow.

These usually develop as a result of three things, sometimes in combination: repetitive work, forceful exertion or an awkward position, which may include using vibrating equipment.

For an action to be repetitive, the rule of thumb is that the worker does it at least four hours a day, said Duffy.

“The disorders don’t come on suddenly,” she said. “It’s difficult to quantify repetition because there are so many variables. Someone in health care may be lifting people day, after day with no change and then one day they do a lift and they feel discomfort or acute pain.”

Forceful exertion is also tricky to quantify. An example could be a worker who has to keep a finger on the trigger of a tool all day which creates a forceful exertion on the finger and hand.

Generally, according to Duffy, anytime the exertion occurs below the knuckle or above the shoulder, there’s a risk for injury. Again, the four-hour rule applies.

“This is why task variety and breaks are really important,” she said.

The third risk — awkward and sustained position — is often the least obvious hazard. Think of an employee on a ladder trying to lift a box from a high shelf or a worker at a computer monitor that sits too high.

“It’s not acute, so it’s a really big problem,” she said. “With other safety hazards like a sharp blade, when you make contact you see the damage and take action.

With MSDs, you don’t cognitively know right away that you’ve done damage to the tissue, so you don’t take action and it escalates.”

There is some controversy over whether or not MSDs are caused by circumstances in the workplace. A 2007 report by the WorkSafeBC Evidence Based Practice Group examined whether MSDs are associated with computer work.

The report looked at previous studies and concluded that there is “no overwhelming evidence that computer work-based activities cause various upper extremity musculoskeletal conditions.”

Every case of injury related to MSDs must be decided on its own merits, said Duffy, because of the variables involved, including the overall health of the worker. However,   she added that as the working population ages, the rate of MSDs will increase.

British Columbia, Alberta, Saskatchewan, Manitoba and Quebec all have regulations that require employers to assess MSD risk factors and take steps to prevent them. Ontario doesn’t yet have specific legislation, but there are guidelines that recommend employers prevent MSDs through educating and training workers.

In July, Wal-Mart Canada was fined in a case involving a worker at a Welland, Ont., store. The employee climbed a ladder to get five boxes of toys from a shelf. On the way down, the worker missed the bottom step of the ladder and fell, suffering arm injuries.
The case is significant because MSD risks are the foundation of other disorders such as fractures, said Duffy. Removing those hazards removes the risk of more acute hazards.

An enforcement blitz involving MSD hazards in April 2009 resulted in more than 4,500 orders, 601 of them related to MSD issues.

Data from the Ontario blitz has not been collected yet, said Duffy. However, “there were tons of orders” for employers to remove MSD risks, she said. It was an eye opener for both employers and inspectors.

“We’ve never done a blitz solely on this topic before,” said Duffy. “We’re trying to create an on-going awareness.”

It’s important for employers to make themselves aware of situations that pose MSD risks, said Duffy, but it’s equally important for them to investigate injuries that may be related to those risks.

“When you do have incidents —  when someone takes time off because of an MSD — you need to do an investigation and do it to the same degree as you would an acute injury,” she said.

Danielle Harder is a freelance writer based in Brooklin, Ont. 

Eliminating risk of MSDs at work

Employers can take several steps to reduce the risk of MSDs by:
•Changing job design: Mechanize repetitive tasks, rotate workers between tasks, build variety into the job and use teams to carry out a job that may pose an MSD hazard.
•Changing workplace design: Evaluate the sources of MSDs and adjust.
•Changing tool and equipment design: Provide workers with proper jigs or fixtures for tasks that require holding.
•Changing work practices: Provide training for workers in jobs that involve repetitive tasks. Emphasize rest periods to give muscles a break and allow them to heal.

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