Working in the heat wave? Here are your rights in Ontario to stay safe from heat stress

Hamilton Spectator

23-06-2025

A
heat wave
is crashing down on Ontario this week and people are running for cover in
air-conditioned buildings and public pools
.
But for some, there's no place to hide. Those working in construction, agriculture and other industries are coming face-to-face with blistering sunshine and a
humidex high in the 40s
that is expected to continue into Tuesday.
Ontario law requires employers and supervisors to take every reasonable precaution to protect workers in extreme heat. But what does that actually mean — and what can you do if your employer isn't meeting that bar?
Here's what you need to know.
Under Ontario law, there is no specific temperature at which it is considered too hot to work, according to Lior Samfiru, a Toronto-based employment lawyer and co-founding partner at Samfiru Tumarkin LLP.
But the law requires employers to take reasonable steps to protect workers from the heat, whether indoors or outdoors.
'Ultimately, employers have to understand that working out in extreme temperatures can have significant health effects,' Samfiru said. 'The employer is the one responsible for helping the employees avoid those situations.'
Those working in construction, agriculture and other industries are coming face-to-face with blistering sunshine and a humidex high in the 40s that is expected to continue into Tuesday.
The law doesn't mandate specific precautions an employer must take.
Precautions might be as simple as ensuring workers have rest breaks, access to water and a properly-ventilated space, Samfiru said. It could also include modifying the work schedule to be outside peak hours, adjusting clothing to be looser and lighter, or providing a tent or umbrella to create shade, according to Jan Chappel of the Canadian Centre for Occupational Health and Safety.
Regardless, employers have to proactively put guidelines in place to reduce the effects of heat on workers.
'To simply say, 'Well, if you have a problem, let me know, employee,' that's not going to be good enough,' Samfiru said.
You have the right to refuse work if you consider it unsafe.
The first step is to report your concerns to your supervisor, said Chappel, a senior technical specialist in occupational health and safety. If your employer doesn't address your concerns, you can call in the workplace's health and safety committee.
If you still feel like your concerns aren't being addressed, you can call an inspector from the Ministry of Labour, Chappel said.
The inspector may find the conditions are safe, or they may deem the conditions unsafe and order the employer to change their conduct, Samfiru said. In either scenario, the employer can't punish you for voicing your concerns, so long as it was done in good faith.
Under Ontario law, there is no specific temperature at which it is considered too hot to work, according to Lior Samfiru, a Toronto-based employment lawyer
'The employer can't say, 'Well, I told you everything was fine, employee. You didn't listen to me so I'm going to punish you,'' Samfiru said. 'That's illegal. You have this right to refuse unsafe work, free of any repercussions.'
The employer can offer the work to someone else, but that person must be told why the work was previously refused, Chappel said.
'Someone else can step up and do the work, but they have to understand the hazards that are present,' she said.
The biggest risk from working when it's hot out is heat stroke, which can sometimes be fatal, Chappel said. It's important that everyone in a workplace knows the symptoms, because often the person with heat stroke won't notice it themselves.
Symptoms include sudden or severe fatigue, nausea, dizziness, light-headedness, disorientation and confusion. Importantly, someone experiencing heat stroke might not be sweating, Chappel said.
If you see someone with these symptoms, move them to a cool place and get them medical attention.
An estimated 220 workers die annually in Canada from occupational heat stress, according to Occupational Health Clinics for Ontario Workers in 2024.
It's important to understand that employers have to take steps to protect you from the heat, Samfiru said.
'There's always this fear, 'If I upset my employer, if I tell them I'm not comfortable working, I don't think it's safe,' … there's fear of retaliation,' he said. 'Employees should know that you have a right to advocate for yourself, even if it turns out that you were wrong.'
A worker at a construction site in Toronto on Monday, amid a heat warning in Toronto and other parts of Ontario.