OHS Canada Magazine

Employers must consider health, safety of workers in spells of hot weather

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July 14, 2021
By The Canadian Press

Environment/Climate Change Health & Safety heat stress

By Len Gillis, Local Journalism Initiative Reporter


Summer has just started but already many Northerners have noticed that this could be one of the hotter summers we have encountered in recent years. Environment Canada said one of the hottest summers in recent memory in Sudbury was in 1988.

Some Sudburians will remember that daytime temperatures were so hot, up to 36.6 Celsius, that some of the running events were pushed back into the evenings which were cooler.

Regardless, as parts of Canada are experiencing record-breaking heatwaves, employers are being reminded that they have a duty to provide employees with a safe working environment.

Peninsula Canada, a human resources consulting firm in Toronto, said this week “it is critical that businesses know how to protect their outdoor workers.”


In an email interview, Hope McManus, Peninsula’s head of health and safety, said Ontario’s occupational legislation spells out the requirements for employers.

“This includes protecting them from the hazards posed by heatwaves. As there is still quite a bit of summer left, employers should be aware of their obligations to staff and how to ensure safe work during hot working conditions. Given the hot temperatures parts of Canada can experience during the summer, it is important that businesses have a heat stress plan in place for their outdoor workers,” said McManus.

Her comments were supported by Kalem McSween, a spokesperson with the Ontario Ministry of Labour, Training and Skills Development.

“Employers have a duty under section 25(2)(h) and supervisors under section 27(2)(c) of the Occupational Health and Safety Act to take every precaution reasonable in the circumstances for the protection of a worker. This includes developing hot and cold environment policies and procedures to protect workers in hot and cold environments,” said McSween.

He said this would include a heat stress prevention program to establish the following:

  1. Worker training in the hazards, health effects and prevention of heat related illness;
  2. Criteria or monitoring method (e.g. acting on heat wave or alert notices by Environment Canada or calculating humidex from temperature and humidity measurements or WBGT measurements);
  3. A monitoring/sampling plan (e.g. when, where and what to measure or monitor);
  4. Responses or preventative measures (e.g. increase frequency of breaks, reduce the work pace and workload, avoid working in direct sunlight, schedule heavy work for cooler part of day, wear hat and sun screen outdoors, etc.);
  5. A water supply plan and encourages hydration (e.g. at least 1 cup every 20 min.); and
  6. First aid and emergency responses, including monitoring of worker symptoms, and investigating incidents of health related illnesses.

For more information the ministry provides a heat stress advisory online.

B.C. heat wave fuels earnestness in climate change discussion

McManus said heat stress is a situation that requires serious attention in the workplace.

“Employers should watch out for the signs of heat stress. These include excessive sweating, dizziness, nausea, irritability, fainting, headache and confusion, heat rash, difficulty breathing and muscle cramps. Causes of heat stress include radiant heat from direct or indirect sunlight or high humidity. Another cause of heat stress could be highly active work or the health of the worker.”

McManus added that heat stress means the body cannot cool itself down fast enough. Usually sweating helps to cool our bodies, however in extremely hot and humid weather, McManus said the body may not be able to get rid of excess heat sufficiently. This could lead to heat disorders such as heat cramps, heat exhaustion and heat stroke. The latter could be fatal if not treated right away, she said.

McManus added that employers should evaluate whether they can provide a cooler working environment and modify the workplace to minimize hazards.

“For example, installing air conditioners and creating shaded areas for work and rest can help protect workers from heat stress,” said McManus.

She added that it would be a good practice to assign more workers than usual to get a job done, so as to lessen the workload.

Len Gillis is a Local Journalism Initiative reporter at Sudbury.com. He covers health care in Northern Ontario.


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