IN MAY 2014, a maintenance worker was using a power washer to clean an underground parking garage in Toronto, unaware that the air around him was slowly becoming toxic. He later was pronounced dead at the hospital from carbon monoxide exposure.
The employer was recently fined $75,000 for failing to protect the worker’s health and safety. Regulation 833 in Ontario’s Occupational Health and Safety Act (OHSA) requires every employer to take all measures reasonably necessary to limit workers’ exposure to hazardous agents. In the case of carbon monoxide, exposure should not exceed 125 parts per million (ppm) at any one time. On the day in question, levels in the garage rose to 425 ppm.
An investigation into the case revealed that neither the workers nor the supervisor had received formal training on the hazards of carbon monoxide or how to protect themselves from poisoning. In fact, they hadn’t received any formal health and safety training other than Workplace Hazardous Materials Information System (WHMIS), and some had not even received that.
While legislation about indoor air quality differs across Canada, Canadian occupational health and safety regulation states that when there is no specific legislation on the topic, all employers and building owners must oblige by the “general duty clause.” This clause, common to all Canadian occupational health and safety legislation, states that an employer must provide a safe and healthy workplace that includes good quality air.
In B.C., WorksafeBC regulations address indoor air quality in all workplaces and require that a workplace is inspected and measurements are taken — but only if there’s a complaint, said Elia Sterling, president of Theodor Sterling Associates in Vancouver. But there’s no specific requirement to continuously monitor unless it’s considered to be an industrial setting.
“A worker in a parking garage in a commercial building, that would be kind of a grey area where it would be assumed the building standards would protect the worker because the fans would be set to turn on if the level were to exceed a certain point.”
Educating workers about environmental hazards can help manage risk.
Some types of businesses — with areas where gas-powered machines regularly operate — seem a more likely zone for carbon monoxide exposure, at first glance.
“When an employee’s operating any fossil-fired fuel equipment, an employer should protect them with good ventilation and an air monitor,” said Ben Scipione, director of health and safety at Paramount Safety Consulting in Hamilton, Ont.
Carbon monoxide buildup can also come from furnace rooms and gas appliances like cooktops, said Sterling.
There’s risk outside of industrial settings, as well.
“Our research has shown that greener, newer buildings are not safer,” said Sterling.
“Problems occur when different ventilation systems for different parts of the building work to defeat each other. For example, for energy efficiency purposes, many exhaust systems for parking garages are on a sensor and are not continuous. Building ventilation systems may also operate intermittently.
“Then there’s a pressure differential between the parking garage or furnace room where carbon monoxide is produced, and the elevator shafts or stairwells leading to the rest of the building. This can cause an effect where the elevator or stairwell actually pulls the contaminant, like carbon dioxide, from the sources to other areas of the building.”
By the numbers
Known as the “silent killer,” carbon monoxide is the leading cause of fatal poisonings in North America, according to the Canada Safety Council.
Exposure to high concentrations can cause death in a few minutes and because it’s odourless and colourless, workers may not be aware they’ve exceeded the recommended exposure limit. Even low concentrations can lead to headaches or nausea.
Workers exposed to low levels of exposure over time might become desensitized, said Scipione.
Waiting for symptoms is not a safe method of monitoring air quality, said Sterling.
“Long-term, low-level exposure does have negative effects,” he said. “There’s a rule of thumb that in an office building, levels should be around one-tenth the occupational health and safety limit.”
A proactive monitoring program is recommended, even if it isn’t required by regulation.
“It is just the prudent thing to do, just a risk management tool. I would urge all building owners and employers to implement a proactive air quality management system,” said Sterling.
Melissa Campeau is a Toronto-based freelance writer.
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