Experts say climate-driven heat and cold are now ‘workplace risk multipliers’ — and employers must rethink policies, from kitchens to postal routes
Canada’s new thermal stress rules are arriving as climate change makes heat and cold a daily operational concern in many workplaces, from warehouses and postal routes to commercial kitchens and transit yards.
The Canada Labour Code amendments, updated on Feb. 12, 2026, set out detailed expectations under Part X of the Canada Occupational Health and Safety Regulations (COHSR), including the use of ACGIH Threshold Limit Values (TLVs) for heat and cold, monitoring tools like humidex and wind chill, and specific requirements for training, reporting and controls under Part II of the Code.
For global health researcher Godfred Boateng and environmental physiologist Stephen Cheung, the changes mark a shift from treating climate and weather as background noise to understanding them as significant operational factors and multipliers of workplace risk.
Climate change as a workplace risk multiplier
The federal guideline for the amendments, “Thermal Stress in the Work Place” outlines a link between health, productivity and legal duty, stressing that extreme heat and cold can cause serious illness, injuries and fatalities, and that effective thermal stress management programs improve productivity and injury rates.
For Boateng, associate professor of global health and Canada research chair in global health and humanitarianism at York University, “it’s high time” for employers to stop seeing climate impacts as purely environmental.
He sees the federal guidelines as a valuable framework, particularly for smaller employees, to craft proactive policies and practices, shifting away from reactive approaches that he says no longer suffice.
“Climate change within occupations or the work setting has become kind of a workplace risk multiplier,” Boateng says, stressing that environmental changes at today’s pace and intensity “have compounding impacts on the health of the workforce, but also have consequences for healthcare. If you have several people being absent … it means loss of productivity.”
Who is most exposed – and why office workers aren’t off the hook
The federal guideline requires employers to protect indoor workers from exposures above ACGIH TLVs for both heat and cold, not only during declared heat waves or cold emergencies.
For Cheung, professor of kinesiology and senior research fellow at Brock University, the list of vulnerable roles goes beyond traditional outdoor work. His Environmental Ergonomics Lab has worked with the military, Coast Guard, Arctic search and rescue teams and clothing manufacturers, but he is quick to point to indoor heat in everyday settings.
“As an example, commercial kitchens can be extremely hot,” Cheung says, explaining how thermal stress can still occur in indoor, confined environments. He urges employers to see the new federal labour code guidelines as more than just rote warnings to respond to during extremes, but rather as an everyday, operational issue.
“It's not just about, ‘Oh, there's an extreme heat warning, and we need to protect our workers,’” he says, and recommends “predicting ahead of time what might be a really challenging environment and then adapting the workload to it.”
Both experts stress that the impact of thermal stress will be felt most acutely in jobs that are already physically demanding or regularly exposed to the elements. The federal guideline names postal contractors and employees, longshoring, barge workers and outdoor emergency response roles among its primary target audience.
Boateng adds that the impacts of climate change are widespread, even if they show up differently in different sectors or roles, and employers should be preparing for unexpected costs.
“Every employer needs to take a cue from this,” Boateng says.
“It might not just be a direct impact. Let's say the office worker might not feel it directly, but the expenditure, when it comes to how much is paid for hydro, how much is paid for electricity, for cooling the place … the cost is being paid by the employer.”
What thermal stress does to the body
Cheung’s own research focuses on what happens when the body can no longer hold its core temperature around 36.5 to 37 C. He defines thermal stress as “basically any time the body becomes really heated up or really cold” and notes that both environmental conditions and workload matter.
When core temperature rises, the consequences go far beyond discomfort, he says. Due to increased metabolism requirements and impaired muscle capacity, employees who are working too hard to stay cool become accident prone.
This means employers need to do better than checking the weather in assessing thermal stress risk. It's a balance of looking at both how hard an individual is working, and also how hot the environment is, says Cheung.
“The risk of accidents can happen even at relatively low thermal strain, where our body temperature may not be at a really high critical level, but our decision-making can be impaired already at a much lower level,” he says.
“Not just acute accidents, but you're also increasing the risk for muscle strains and pulling a muscle or those kinds of injuries … there's also the long-term health risk of just repeatedly being exposed to a very hot environment or in a very cold environment.”
Cheung is blunt about one of the most common misconceptions in workplaces: that experience and toughness can overcome heat: “If you are a rookie ... you'll get used to it.” Even the most highly trained Olympic level athletes have physiological limits, and workers should not be expected to “adjust” to high or low temperatures, he says.
