Blazing temperatures are no longer just a seasonal occurrence—they’re a growing workplace hazard. Every summer, Canadian workers face hotter conditions on job sites, especially in construction, agriculture, landscaping, and delivery work. 

With longer daylight hours and increasing pressure to meet deadlines, more workers are spending extended hours under the sun. 

This can push the body past its limits, putting employees at risk of heat stress, dehydration, and even heatstroke.

Statistics on workplace heat stress show just how serious this issue is becoming. Between 2000 and 2021, Canada recorded over 470 heat-related illness claims—and experts believe that’s just the tip of the iceberg due to underreporting. 

In provinces like British Columbia and Ontario, summer heatwaves are hitting harder and lasting longer, often triggering multiple heat warnings in a single season.

Employers need to understand the true impact of heat on worker health and safety. This isn’t just about physical comfort—it’s about preventing long-term health risks, lost productivity, and even fatal incidents. 

The effects of extreme heat can sneak up quickly, especially when workers aren’t properly trained or equipped.

In this blog, we’ll walk you through 10 powerful statistics on workplace heat stress that every employer should know. 

These facts will help you recognize the risks, take preventive action, and keep your team safe through the hottest months of the year.

10 Eye-Opening Statistics on Workplace Heat Stress

Heat stress is a serious occupational hazard that can cause illness, injury, and even death.  The following ten statistics reveal how widespread and under-recognized the problem is, especially as climate change leads to longer and more intense heatwaves. 

From global injury rates to sector-specific risks, each number paints a clear picture: employers need to take heat exposure seriously, both outdoors and indoors.

Let’s explore the key statistics shaping the conversation around heat stress at work.

1. Global Occupational Injuries from Excessive Heat

Each year, over 23 million workers around the world suffer injuries related to excessive heat, according to the International Labour Organization (ILO). 

These injuries aren’t just limited to heat exhaustion or heatstroke. In many cases, heat stress contributes indirectly to accidents such as falls, equipment misuse, or fainting on the job.

Here’s what you need to know:

• Heat can impair focus and judgment. When workers are overheated, they make more mistakes—putting themselves and others at risk. For example, a roofer may misstep due to dizziness or a factory worker may lose control of machinery due to fatigue.
• 23 million heat-related injuries represent around 1 in 3 workplace injuries in high-exposure industries in low- and middle-income countries.
• Construction, agriculture, mining, and outdoor maintenance are the hardest-hit sectors globally. In these jobs, long hours under direct sun and physically demanding tasks increase the risk of heat-related illness or accidents.

The risk isn’t limited to outdoor workers. Indoor workers in poorly ventilated environments, such as commercial kitchens, factories, confined spaces, warehouses, and processing plants, are also highly exposed to heat stress—especially when machinery generates extra heat and cooling systems are lacking.

Heat exposure is a recognized occupational hazard in Canada. Provinces like British Columbia, Alberta, and Ontario have seen a rise in heat-related illness claims over the past decade, particularly during July and August.

Even if your workers aren’t outside, they’re not necessarily safe. High indoor temperatures, poor airflow, and inadequate breaks can be just as dangerous as working under the summer sun. 

It’s time to rethink how heat affects worker safety across all environments—not just construction sites.

2. Annual Death Toll from Workplace Heat

Every year, an estimated 19,000 workers around the world die due to heat exposure on the job. These deaths are not inevitable—they’re largely preventable with the right awareness, planning, and safety controls.

Here’s what contributes to this tragic toll:

• Lack of safety regulations: In many developing countries, there are few or no formal workplace heat safety standards. This leaves millions of outdoor labourers in sectors like farming, construction, and street vending vulnerable to extreme conditions.
• Inadequate employer action: Even in countries with guidelines, many employers don’t have written heat safety policies or fail to train workers on recognizing the signs of heat illness.
• Delayed emergency response: Many fatal cases stem from a lack of first aid knowledge, late recognition of symptoms, or delayed medical attention once someone collapses.
• Poor access to hydration and shade: Workers in high-risk settings often lack access to shaded rest areas or regular hydration breaks, both of which are essential for preventing heat-related illness and death.
• Vulnerable populations most affected: Older workers, those with pre-existing medical conditions, and migrant labourers are often disproportionately impacted due to harsher working conditions or limited access to healthcare.

While workplace heat-related deaths are rare, the risk is increasing. With climate-related events such as the 2021 British Columbia heat dome, which caused nearly 600 deaths overall, there is growing concern about worker safety during extreme weather events.

These 19,000 annual deaths shouldn’t happen. With proper training, early intervention, and common-sense policies like regular breaks and cooling areas, most of these fatalities could be avoided.

3. Rising Exposure to Heatwaves in the Workplace

In 2020, 231 million workers worldwide were exposed to heatwaves on the job—a staggering 66% increase compared to the year 2000. This sharp rise is directly linked to climate change, which is making heatwaves longer, more frequent, and more intense.

Why this matters

Workplace exposure to heat is not just increasing—it's accelerating. Heatwaves that once occurred once every few years are now happening annually or even multiple times a season in some regions.

Industries under greatest strain

• Agriculture: Farmers often work in open fields without shade and must continue even during peak sun hours.
• Construction and road work: These jobs involve heavy physical labour, usually outdoors, making workers extremely vulnerable to heat exhaustion.
• Logistics and transport: Delivery drivers, couriers, and freight workers spend hours on the road or in hot warehouses with limited cooling.

Public service and infrastructure repair crews face similar challenges, especially during emergency responses in heatwave conditions.

• Productivity losses and injury risk: Extreme heat reduces physical and cognitive performance. Workers slow down, make more errors, and take longer breaks—resulting in lower productivity and a higher risk of accidents.
• Rising absenteeism: Frequent heatwaves can also increase sick days as workers experience fatigue, dehydration, or heat-related illness. This can further strain staffing levels and increase turnover.

Canadian employers are not immune to this trend. According to Environment and Climate Change Canada, the number of heat warnings issued has been rising across the country, including in historically cooler provinces like Manitoba and Newfoundland.

If heat safety policies don’t evolve to match climate realities, we’ll continue to see a rise in injuries, absenteeism, and long-term health risks—especially during peak summer months.

4. Heat Stress Is a Widespread Global Workplace Risk

In 2020, 71% of the global workforce (about 2.41 billion people) were exposed to excessive heat while working. 

This staggering figure, reported by the International Labour Organization (ILO), highlights the global scale of workplace heat stress. It’s not an isolated issue—it’s a global public health and labour crisis.

Here’s how this plays out around the world:

• Asia: Countries like India, Bangladesh, and Pakistan face regular extreme heat conditions, especially during pre-monsoon and summer seasons. Millions of workers in textiles, construction, and agriculture work without formal safety policies or adequate hydration access.
• Africa: In Sub-Saharan Africa, informal sector workers—including street vendors, miners, and agricultural labourers—face heat daily. Many don’t have legal protection or employer-provided shade, water, or breaks.
• The Americas: In both North and South America, heat stress impacts outdoor workers in farming, landscaping, and delivery services. In Central America, sugarcane workers have experienced spikes in chronic kidney disease tied to dehydration and heat exposure.

This stat also matters for Canadian employers. As global supply chains tighten and Canadian industries rely more on international contractors, outsourced labour, and seasonal workers, heat safety must be viewed beyond borders. 

If Canadian companies operate internationally or bring in foreign seasonal workers, they must address heat risks with cultural and regional sensitivity.

Why scalable, localized plans matter:

• Climate varies: What works in Alberta won’t work in Southern India or Ghana.
• Local heat thresholds differ: A “heatwave” in Canada might be a normal day elsewhere—but adaptation is still required.

Employers must assess risk based on job type, location, and exposure time—not just a thermometer reading.

With over two-thirds of the global workforce at risk, heat stress management must be part of a company’s safety strategy—whether they’re on a farm in Saskatchewan or sourcing materials from overseas.

5. Construction Industry’s Heat Death Share in the U.S.

In the United States, the construction industry accounts for a staggering 34% of all heat-related workplace deaths, despite representing only a portion of the total workforce.

This figure from the U.S. Bureau of Labor Statistics highlights how construction workers are among the most vulnerable to heat on the job.

Here’s why construction is so dangerous in hot conditions:

• Outdoor exposure: Construction sites are almost always exposed to direct sun, especially during roof work, road building, and framing. There’s often little access to shade, and job sites are rarely scheduled around heat risk.
• Heavy protective gear: Personal protective equipment (PPE) like hard hats, reflective vests, and steel-toe boots are essential—but they also trap heat and reduce the body’s ability to cool itself.
• Limited breaks and hydration: Many crews operate on tight timelines and skip breaks or water intake to stay productive. This increases risk, especially in the afternoon hours when temperatures peak.
• Physical demands: Lifting, drilling, pouring concrete, and working with hot machinery all raise core body temperature faster than in most jobs.

Although this data is from the U.S., the same risk factors apply in Canada, especially during the peak summer construction season. 

Workers in provinces like Alberta, Ontario, and British Columbia often face high UV indexes, rising humidity, and increasingly unpredictable heatwaves.

Current guidance and the need for enforcement:

In the U.S., OSHA offers heat illness prevention guidelines, including water, rest, and shade policies. However, these are not always enforced or adopted.

Canada lacks a nationalized heat safety standard. Provinces issue workplace safety bulletins, but enforcement and employer action remain inconsistent.

What needs to change:

• Construction firms must integrate heat stress planning into daily routines—starting shifts earlier, increasing water stations, enforcing cool-down breaks, and training supervisors to spot heat illness signs.

This stat is a red flag. Without stronger policy and employer accountability, the risk of heat-related deaths in construction will only rise.

6. Annual Heat-Related Deaths in the U.S. Workforce

Between 2011 and 2022, the U.S. recorded 479 heat-related workplace deaths—and in 2023 alone, another 55 workers lost their lives due to excessive heat. 

These numbers come from the U.S. Bureau of Labor Statistics and they show a clear, troubling trend: even in a country with advanced infrastructure and real-time weather monitoring, workers are still dying from preventable heat exposure.

Here’s why this keeps happening:

• Failure to act on known risks: Employers have access to temperature data, forecasts, and wearable heat monitors—yet many still lack a basic heat safety policy or training.
• Lack of federal heat standards: Unlike other occupational hazards, there is no comprehensive federal law in the U.S. that mandates employer responsibility for heat protection. Guidelines exist but are not legally enforced.
• Underreporting and misclassification: Many heat-related deaths are misreported as cardiac arrest or dehydration, meaning the real number may be even higher.

Pushing through heat: In industries like agriculture, logistics, and construction, there’s often an unspoken culture of “toughing it out,” which discourages breaks or reporting symptoms.

Preventive steps that save lives

• Shaded rest areas: Temporary tents or shaded zones near job sites can offer workers quick relief from the sun.
• Buddy systems: Having workers monitor each other for symptoms of heat illness helps catch problems early.
• Scheduled cool-down breaks: These should increase in frequency with the temperature or humidity index.
• Hydration protocols: Providing water every 15–20 minutes and encouraging drinking even before workers feel thirsty.

Even the U.S.—with better data and resources—struggles with enforcement. Canadian employers should view this as a warning and adopt heat policies before serious incidents occur, especially as extreme weather becomes more common.

7. Heat-Related Days Away from Work (DART Cases)

In 2021–2022, the U.S. reported 5,770 heat-related DART cases—a figure that reflects not just injuries, but their impact on business operations. 

For context, DART stands for Days Away, Restricted, or Transferred—a category of workplace incidents where an employee must take time off, change roles, or work under restrictions due to injury or illness. 

Within that, DAFW (Days Away From Work) cases specifically track how many people were unable to return to their usual duties.

Why this matters

These aren’t minor injuries. When someone suffers heat exhaustion, they’re often unable to safely return to the same physical workload right away. They need recovery time—and sometimes a doctor’s clearance.

• Compensation claims spike: More DART cases typically lead to increased workers’ compensation costs, especially in industries with outdoor or physically demanding work.
• Lost productivity adds up: One or two employees off work during a busy summer season can delay projects, reduce output, and increase overtime for others.
• Worker morale drops: Seeing colleagues get sick from heat can increase anxiety, especially if workers feel management isn’t taking precautions seriously.

In sectors like agriculture, construction, landscaping, and warehouse work, DART cases due to heat are a growing concern. Even indoor environments—like poorly ventilated kitchens or factory floors—can lead to similar absences when ventilation or hydration isn’t managed.

What can employers do?

• Introduce job rotation during peak heat hours to reduce individual exposure.
• Use real-time monitoring tools for temperature and worker heart rate where possible.
• Create incident logs and review protocols to analyze causes and prevent repeat cases.

These 5,770 cases represent more than just numbers—they’re warning signs of deeper systemic gaps in heat safety. For Canadian employers, tracking time-loss due to heat exposure can be a powerful motivator to implement more proactive prevention strategies.

8. Low-Income Workers Bear the Brunt

Lowest-paid workers are five times more likely to suffer from heat-related injuries compared to higher-income earners. This statistic shines a spotlight on how economic inequality intersects with workplace safety, particularly during hot seasons.

Why this happens

• Pressure to keep working: Many low-income workers can’t afford to lose a day’s pay or risk being sent home. As a result, they often push through early symptoms of heat illness—like dizziness, headache, or nausea—rather than taking a break.
• Fewer protections and benefits: These workers are often in part-time, seasonal, or non-unionized roles. They may lack access to paid sick days, proper PPE, or a supportive supervisor who encourages heat safety.
• High-risk jobs: Most low-wage workers are employed in physically demanding industries like construction, cleaning, agriculture, landscaping, or warehouse work—where heat exposure is highest.
• Limited training: Safety orientation for these workers often skips over heat illness education, especially in short-term contracts or temporary jobs.

What Canadian employers should do

• Offer paid rest breaks during high heat and educate workers on their right to take breaks when needed.
• Ensure all workers (regardless of pay or role) receive the same safety training and equipment.
• Build a culture where workers feel safe reporting heat symptoms without fear of job loss or reprimand.

No one should risk their health because of their income level. Equal protection must be the standard—not a privilege—when it comes to workplace heat safety.

9. Latino Workers Disproportionately Affected

In the U.S., Latino workers account for about one-third of all heat-related deaths, even though they represent a smaller portion of the total workforce. This shows how racial and language disparities contribute to unequal heat safety outcomes.

Key reasons behind this disparity

• High exposure industries: Latino workers are heavily represented in agriculture, roofing, landscaping, and food processing—jobs that involve long hours in extreme heat.
• Language barriers: Many training programs and safety signs are offered only in English. This makes it difficult for workers with limited English proficiency to fully understand heat illness symptoms or emergency procedures.
• Cultural factors: In some cases, workers may avoid reporting discomfort or symptoms out of fear of losing their job, appearing weak, or being viewed as difficult.
• Lack of advocacy: These workers often don’t have access to unions, legal resources, or HR support that could help enforce safety standards.

What can employers in Canada do?

• Offer bilingual safety training and signage where applicable.
• Use visual aids and hands-on demonstrations to make heat safety more accessible.
• Assign safety champions or team leads who speak multiple languages to monitor for early signs of heat stress.
• Encourage open communication and emphasize that worker health is a top priority, no matter their background.

Why it matters

Heat stress prevention must be culturally inclusive. The goal is not just compliance—it’s ensuring that everyone understands how to stay safe on the job.

10. OSHA Is Actively Cracking Down on Heat Hazards

Between April 2022 and December 2024, OSHA conducted around 7,000 heat-related workplace inspections and issued 1,392 Hazard Alert Letters (HALs) to employers across the U.S. 

This shows a major shift: regulators are no longer waiting for accidents—they’re proactively enforcing heat safety standards.

What this means

Inspections are increasing: OSHA has started targeting high-risk industries—like construction, warehousing, and agriculture—especially during heatwaves or in regions under heat warnings.

What’s a Hazard Alert Letter (HAL)?

A HAL is an official document sent to an employer to notify them of unsafe working conditions related to heat. While it’s not a fine or citation, it’s a strong warning that future non-compliance could result in penalties or enforcement action.

• Purpose of HALs: They push employers to act fast—reviewing safety procedures, conducting risk assessments, and improving protections before workers are harmed.

Even though OSHA is a U.S. agency, Canadian regulatory bodies may follow a similar path. With climate change raising the stakes, Canadian provinces are likely to step up inspections and tighten enforcement on heat safety in the coming years.

Why this matters for employers

• Don’t wait for enforcement. Create and implement a heat stress prevention plan now.
• Document your efforts—training logs, hydration schedules, emergency protocols—to prove due diligence.
• Consider internal heat audits or third-party evaluations to find and fix gaps before an incident happens.

Heat safety is no longer optional. Regulatory bodies are watching, and employers need to be ready with real action plans, not just promises.

What Employers Can Do to Improve Heat Stress Safety

As temperatures rise, employers have a legal and moral duty to keep workers safe from heat-related illness and injury. 

Whether your team works outside in construction or indoors in a hot warehouse or kitchen, preventing heat stress starts with preparation, policy, and proactive measures. 

The good news? Many heat safety improvements are low-cost and easy to implement right away.

Here are practical steps employers can take to protect their workforce:

1. Conduct Heat Risk Assessments During High-Temperature Months

• Review job roles, tasks, and locations that involve high heat exposure—especially in summer.
• Use Environment Canada’s heat warnings and the humidex to determine risk levels.
• Involve workers and supervisors in identifying heat-prone areas (e.g., rooftops, unventilated sites, kitchens).
• Reassess frequently during heatwaves or changing weather patterns.

2. Provide Shaded Areas and Scheduled Breaks for Outdoor Workers

• Set up temporary shelters like tents or tarped areas at construction sites or fields.
• Enforce mandatory cool-down breaks, increasing frequency as the temperature or humidity rises.
• Use signage or digital reminders to signal when it's time to rest.

3. Ensure Availability of Cool Drinking Water on Site

• Make water stations easily accessible and refill them regularly throughout the day.
• Encourage workers to drink water every 15–20 minutes, not just when they’re thirsty.
• Consider electrolyte solutions or sports drinks for physically demanding roles.

4. Train Employees to Recognize Heat Illness Symptoms

• Teach staff to spot early warning signs: headache, fatigue, muscle cramps, nausea, or confusion.
• Use visual posters, toolbox talks, and short training videos to reinforce heat safety education.
• Include guidance on how to assist coworkers showing symptoms and when to seek medical help.

Canada Safety Training Centre offers Heat Stress Awareness Training, designed to raise awareness about the dangers of heat stress and equip individuals with the knowledge and skills to recognize, prevent, and manage heat-related illnesses.

The purpose of this training is to ensure the safety and well-being of workers who are exposed to high temperatures in their workplace.

5. Use Wearable Tech or Heat Sensors Where Possible

• Invest in wearable monitors that track body temperature, heart rate, or hydration levels.
• Install digital thermometers or heat index boards at work sites to monitor real-time conditions.
• Use alerts to warn supervisors when conditions reach dangerous thresholds.

6. Create and Communicate a Heat Stress Response Plan

• Develop a written heat illness prevention and response plan specific to your work environment.
• Clearly outline steps for emergency care, who to contact, and when to stop work.
• Communicate the plan in multiple languages if needed, and make sure every worker knows their role.

With climate change intensifying heat risks, the time to act is now. These simple but essential strategies can reduce heat-related incidents, improve worker well-being, and help your business stay compliant with evolving safety expectations.

Conclusion

Heat stress is a growing workplace hazard that affects millions of workers across the globe, including here in Canada. 

As climate patterns shift and extreme heat events become more frequent, the risks to employee health, safety, and productivity will only rise.

The statistics on workplace heat stress speak for themselves: rising injury rates, preventable deaths, and growing numbers of missed workdays. But the good news is that heat-related illness and injury are largely preventable—if employers take the right steps.

Simple measures like providing shade, ensuring access to cool drinking water, and training employees to recognize heat illness symptoms can go a long way. 

Adjusting work schedules to avoid peak heat hours, introducing rest breaks, and using wearable technology to monitor conditions are equally valuable.

More importantly, employers must build a workplace culture where safety comes first, regardless of deadlines or productivity pressures. 

Every organization—large or small—can and should implement a heat stress prevention plan tailored to their industry and work environment.

As summers get hotter, it’s no longer enough to react to heat stress after it happens. Proactive planning and policy are key to keeping workers safe, healthy, and able to perform their jobs year-round.