WORK REFUSALS – How Hot Is Too Hot: Heat Stress as Grounds for Refusal


The OHS laws give workers the right to refuse dangerous work without being subject to discipline or reprisal. This is an important protection. But it’s also a measure of last resort. Workers are expected to tolerate some level of discomfort and even pain when they work. The right to refuse to do a job kicks in only if there’s a real or reasonable (depending on the province’s OHS law) danger to health and safety.

At best, working in heat and humidity, indoors and outdoors, is uncomfortable, especially if the work is strenuous and/or the worker has to wear certain equipment to do it. At worst, it might involve a danger of serious and even fatal heat illnesses such as heat stroke (for simplicity’s sake, we’ll refer to heat illnesses collectively as “heat stress”). The problem: It’s hard to tell when hot-weather work crosses the line from being merely uncomfortable to being dangerous. That in turn makes it difficult to determine if a worker has the right to refuse the work.

So what do you do when one of your workers throws down his shovel and refuses to work because he’s afraid of suffering from heat stress? Unfortunately, the law doesn’t supply a clear answer. All it does it set out general principles regarding work refusals. To figure out how these principles apply in the context of heat stress refusals, you must track down and analyze the actual cases. That’s what this piece does


We found 7 cases where a court had to decide if there was a real danger of heat stress to workers. 4 of the cases were federal, 2 were from Ontario and 1 was from Nova Scotia. The court ruled in the worker’s favor and upheld the refusal in 3 of the cases. Although the facts of the cases were all different, the approach of the courts was remarkably similar.

Factor 1: Physical Conditions

In non-scientific terms, the risk of heat stress arises when high temperatures and humidity levels coupled with physical activity causes the body to absorb heat faster than the body can get rid of it. In essence, the body overheats. So in deciding if a danger existed, you’d think that courts would focus on physical factors such as how hot it was in the workplace when the refusal took place. To some extent, they do; but not as much as you might expect. Examples:

> Thermal Conditions: When we started writing this article, we planned to list the actual thermal conditions present in each workplace where a heat stress refusal took place. This might, we thought, give safety coordinators a frame of reference for determining when it’s “too hot to work.” But, alas, it was not to be. It was when we set out to gather this data that we discovered something pretty surprising: Courts don’t seem to care that much about thermal conditions in refusal cases. Of the seven cases we analyzed, only three bothered to cite the temperature of the workplace; and none mentioned humidity, air movement or sources of radiant heat.

There was one glaring exception: A NS arbitrator cited Wet Bulb Globe Temperature readings from a workplace over a roughly 90-minute period [International Brotherhood of Elec. Workers, Local 625 v. Black and MacDonald, Ltd.].

> Clothing: Clothing affects the worker’s body’s absorption and regulation of heat. So you’d think that it would be a central factor in refusal cases. But, apparently, it’s not. The courts talked about what workers were wearing only when it was at the center of the dispute. For example, an Ontario arbitrator ruled that hotel doormen forced to wear four-layered polyester “Beefeater” uniforms in summer were at risk of heat stress and had a right to refuse [Re Westin Hotel, Restaurant and Cafeteria Employees’ Union, Local 75].

> Engineering Controls: OHS regulations and guidelines require employers to implement engineering controls such as ventilation to keep thermal conditions at safe levels. But the presence or absence of such controls played a key role in only one case: A federal arbitrator’s ruling that a railroad cook could refuse to work in an un-air-conditioned and poorly ventilated kitchen in the summer [LeBlanc and VIA Rail Canada Inc.].

> Physiological Measures: Heat stress can be measured by physiological parameters such as core body temperature and heart rate. But, continuing the theme, the cases suggest that courts don’t use these measures to determine if a refusing worker was at risk of heat stress. Only one court mentioned physiological factors: The Ontario arbitrator that ruled in favor of the hotel doormen cited the testimony of an industrial hygienist that the polyester Beefeater uniforms created a significant risk of heat stress because they restricted heat transfer through radiation, convection and evaporative cooling [Westin Hotel].

> Administrative Controls: Employers can take a number of administrative measures to cut the risk of heat stress, such as allow for frequent breaks, schedule intense work early or late in the day or acclimatize workers to working in the heat. But only two courts cited administrative controls as factors in their decisions: The Ontario arbitrator noted that the hotel doormen felt they had to sneak in breaks during the summer; and a federal arbitrator who ruled against refusing railway workers who claimed ponchos were too hot said the workers could avoid heat stress by taking frequent breaks [Betts and Canadian National Railway].

Factor 2: How the Dispute Was Handled

It would be an overstatement to say that judges don’t care about or pay attention to the physical factors when they decide on heat stress refusals. However, it is fair to suggest that judges spend at least as much time looking at other factors: How the parties behaved during and after the refusal. Let’s look at how these factors have played out in the cases:

> Worker Not Really Concerned for Safety: One of the first things a court looks at in a refusal case is whether the worker acted out of a genuine concern for safety. Workers can’t use a refusal to get out of what is essentially an unpleasant but not dangerous job. Courts are apt to question the sincerity of workers who refuse work in a way that comes across as heavy-handed or graceless. For example, three Ontario steel workers refused to work on a ladlemen’s platform because it was too hot. The plant installed fans and offered alternative work. But the refusing workers were uncooperative. The arbitrator found the refusal invalid. While “conditions were very unpleasant,” the arbitrator ruled that the workers’ didn’t have “reasonable grounds to believe” that they were in any unusual danger [Eastern Steelcasting (Re)].

> Refusal Is a Pretext: A variation on the same theme is the worker or union that uses the refusal not to guard against immediate dangers to health and safety but as a pretext to raise what are essentially long-term labour disputes or grievances.

For example, a sleep-deprived chef refused to work in an overheated kitchen car because she feared that the fatigue and heat would cause her to get into an accident. The chef had what appeared to be a strong case. The kitchen was above 100 degrees F. The hood ventilation fans weren’t working. And the chef had been given less than six hours to recover from an 18-hour shift in the kitchen. But the chef lost. The reason: The union representing her used the grievance to complain not only about the working conditions in the kitchen on the day of the refusal but the lack of mandatory rest periods for all on-board workers. The federal Labour Board found that the union was misusing the chef’s refusal rights as a “vehicle for resolving labour issues” and threw out the complaint [Gray (Re)].

> Worker Wants to Trade Safety for Comfort: Things get especially complicated when the worker has to wear personal protective equipment. Wearing personal protective equipment (PPE) in the heat heightens the worker’s discomfort. But it might also be essential to protect against the hazards attendant to the job. Clearly, a worker can’t shed necessary PPE because it’s too hot. However, workers can insist on being allowed to use the most comfortable PPE that still provides them with the necessary protection. In other words, the worker can’t insist on PPE that provides a lesser degree of safety just because it’s more comfortable.

For example, railyard workers refuse to wash locomotives in the August sun unless they can wear Tyvek suits rather than protective ponchos. The Tyvek suit is more comfortable than the black, unvented poncho. But it doesn’t keep the workers dry the way the poncho does. As a result, if workers are allowed to wear the Tyvek suit, their skin will be exposed to oil, lubricants and other chemicals. So the federal arbitrator rules that they must wear the poncho and take frequent breaks to guard against the risk of heat stress [Betts and Canadian National Railway].

> How Company Handled the Investigation: There are specific procedures employers must follow when handling refusals. Most importantly, the company has to investigate the refusal and determine if there is a danger. How employers handle the investigation can be a major factor in how a court rules in the dispute.

The LeBlanc case above where a train cook refused to work in a hot, unventilated kitchen car is an example of this. Although the arbitrator acknowledged that the kitchen was overheated, the real turning point of the case was the way the railway handled the investigation. The safety officer didn’t bother to check how hot the kitchen really was. He simply ruled that the refusal was unjustified because the cook didn’t report to work before refusing. The arbitrator scolded the officer for basing his ruling on how the cook behaved rather than on the conditions in the kitchen. “His authority extends only to the question of whether danger exists,” said the arbitrator.

But, just to show how subjective refusal cases can be, the failure to investigate might also be held against the worker. Thus, in Gray, the other case where a cook refused to work in a hot dining car but lost because the union turned the case into a battle over general labour conditions, the train pulled out before the railway had a chance to take measurements in the kitchen. So the safety officer interviewed the cook right after the refusal, found her to be in generally good emotional and physical condition and concluded that there was no danger. This time, the Board overlooked the absence of an investigation of the kitchen car and upheld the no danger finding. In other words, the deciding factor was the union’s grandstanding rather than the botched investigation.


So where does all of this leave you?

  • First and foremost, be aware that courts tend to judge the legitimacy of heat stress refusals not simply by thermal conditions but by how the refusal is brought, how it’s investigated, which side is more believable and how the parties behave before, during and after the dispute;
  • If a worker refuses to work because it’s too hot, immediately investigate and document the thermal conditions of the workplace;
  • A refusal to work in the heat is unjustified if it’s a pretext for insubordination, collective bargaining and/or if the worker has an ax to grind; and
  • Workers don’t get to pick the PPE they want to use and employers need not and should not trade thermal comfort for safety. PPE, in other words, must be appropriate to protect against hazards. If it’s hotter, use administrative controls such as frequent breaks to control the risk of heat stress.




1. Re Westin Hotel & Hotel, Restaurant & Cafeteria Employees’, Local 75, 11 L.A.C. (3d) 1, Aug. 16, 1983.

Hotel doormen are justified in refusing to wear heavy polyester Beefeater suits that restrict circulation at neck and knees. Lack of openings in suit restrict heat transfer through radiation, convection and evaporative cooling. The doormen have to work outside away from the air-conditioning and are expected to perform manual labour such as carry guest’s suitcases.

2. LeBlanc & VIA Rail Canada Inc., CLRB Decision No. 714, Board File: 950-93, Nov. 18, 1988.

A railway cook is justified in refusing to work in un-air-conditioned dining car. The cook had a note from his doctor advising him to avoid extreme heat. A railway safety officer didn’t check the heat in the kitchen; but he found the refusal unjustified because the cook hadn’t even bothered to report to work before refusing. The Board reversed the ruling. According to the Board, the safety officer should have worried more about the inside of the kitchen and less about how the cook handled the dispute.

3. International Brotherhood of Electrical Workers, Local 625 v. Black and MacDonald Ltd, [2003] N.S.L.A.A. No. 1.

An electrician in a paper mill refuses to work because of extreme heat. The union gets involved and the case turns into a grievance by workers demanding extra pay under the collective agreement because they have to work in “abnormal conditions.” The mill claims the work is hot but not “abnormal.” The court disagrees and cites detailed WBGT readings in concluding that the work is dangerous and worthy of extra pay for “abnormal” conditions.


1. Gray (Re), [1999] C.L.R.B.D. No. 21, June 28, 1999.

The chef on a train didn’t want to work in a hot dining car on a return trip from Winnipeg to Vancouver. The chef claimed she was fatigued and overheated. She had only four hours—two hours less than normal—to recover after getting into Winnipeg. The kitchen was hot and the stove ventilation fans weren’t working right. But the chef decides to tough it out. She works the trip and files a grievance later. But the Board rules against her. By the time she initiated the refusal, the train was long gone and there was no way the safety officer could check it out.

2. Eastern Steelcasting (Re), 28 L.A.C. (2d) 310, (1981).

Three Ontario steel workers refused to work on a ladlemen’s platform because it was too hot. The plant installed fans and offered alternative work. But the workers won’t budge. The arbitrator found the refusal invalid. While “conditions were very unpleasant,” the arbitrator ruled that the workers’ didn’t have “reasonable grounds to believe” that they were subject to any unusual danger

3. Canadian Airlines International Ltd. & International Assn. of Machinists & Aerospace Workers, Transport Dist. 140, [1999] C.L.C.R.S.O.D. No. 24, Oct. 26, 1999.

An airline ramp attendant had no justification for refusing to handle baggage in the cargo pits of a military plane. The pit was hot. The attendant, who was supposed to wear coveralls with large openings around the wrists and ankles, claimed that he was afraid fiberglass dust would get on his skin, react with the heat and cause rashes. The arbitrator didn’t buy it. Refusals are designed to protect against immediate dangers. The attendant had been working in the pits and getting rashes for 12 months. That was unfortunate; but it wasn’t the kind of immediate hazard justifying a refusal, the arbitrator said.

4. Betts and Canadian National Railway, [2005] C.L.C.A.O.D. No. 50, Dec. No. 05-51.

A Manitoba rail yard worker refuses to scrub locomotives in the August heat because he’s afraid of getting heat stress. The railway wants him to wear a black, unvented poncho; he wants to wear a Tyvek suit. An expert testifies that the poncho stems air circulation and increases the risk of heat stress. The Tyvek suit is much more comfortable. But it doesn’t protect the worker’s skin against oil and contaminants as well as the poncho. So the arbitrator finds that the worker must wear the poncho and take frequent breaks to deal with the heat.