Managing heat stress in the workplace

Worker experiencing heat stress

Prevention tips to keep workers safe in hot environments

Information sheet: Managing heat stress in the workplace - Download and share

As temperatures rise, so does the risk of heat-related illness on the job. Whether working outdoors in forestry, or indoors in hot environments like underground mines, workers can quickly become vulnerable to heat stress if proper precautions are not in place.

Heat stress occurs when the body cannot cool itself effectively. Hot temperatures, humidity, physical exertion, radiant heat from equipment or the sun, heavy clothing, and personal protective equipment can all contribute to dangerous working conditions. Without prevention measures, heat stress can lead to dehydration, heat exhaustion, or life-threatening heat stroke.

Common warning signs of heat stress include:

  • Dizziness or fainting 
  • Headache or nausea 
  • Muscle cramps 
  • Heavy sweating 
  • Weakness or fatigue 
  • Confusion or unusual behaviour 
  • Dark-coloured urine, a sign of dehydration

This poster describes what heat exhaustion and heat stroke both look like.

How to protect yourself against heat stress 

Sometimes it’s difficult to self-recognize heat stress. Consider the following best practices for your protection when working in warm environments: 

  • Stay fit 
  • When possible, avoid working in hot areas and in direct sunlight
  • Take frequent breaks 
  • Use sunblock with at least 15 SPF and re-apply every two hours 
  • Cover up with long-sleeve shirt, hat 
  • Increase fluid intake 
  • Avoid alcohol and excessive caffeine 
  • Reduce activity when exposed to heat 
  • Use buddy system to watch for symptoms 
  • Increase salt intake (if doctor approves) 

How employers can protect workers against heat stress 

  • Train workers in heat stress awareness and first aid 
  • Provide drinking water (recommendation is one cup of water every 20 minutes) 
  • Provide rest breaks and air-conditioned rest areas 
  • Indoors, provide fans for air circulation
  • Use machines to reduce physical demands of work 
  • Schedule strenuous work during cooler times of the day 
  • Measure daily Humidex ratings and have a Humidex Heat Stress Response Plan 
  • Have a heat stress prevention program specific to your workplace  

If someone shows signs of heat exhaustion or heat stroke, move them to a cool area immediately, loosen clothing, provide cool water if they are conscious, and seek medical attention.

Heat-related illnesses are preventable. With awareness, training, and proper controls, workplaces can help keep workers safe in hot environments.

Related

Beat the Heat – Safety Meeting Talk and Leader Guide – Workplace Safety North

Hazard Alert – Heat Stress can be a Killer – Workplace Safety North

Ontario Mine Rescue Heat Stress Report and Heat Exposure Standard – Workplace Safety North

Best Practices for Addressing Heat Stress in Surface and Underground Mining Operations – Workplace Safety North

Heat Stress vs. Heat Stroke – Comparison Poster – SAIF

Heat Stress Toolkit – Occupational Health Clinics for Ontario Workers

Managing Heat Stress at Work – Ministry of Labour, Immigration, Training and Skill Development