Part of Prevention

Working in extreme temperatures

Health and safety information and work site practices for working in extreme cold or heat.


Understanding the health risks involved with working in extreme temperatures can help employers protect their workers. While this information is most relevant to outdoor workers, it may also help workers in hot or cold indoor environments.

For more information, see the Working Safely in the Heat and Cold publication.

Working in extreme cold

When you work in extreme cold, most of your body’s energy is used to maintain a consistent inner temperature. However, your body’s ability to adapt has limits. Cold stress occurs when your internal body temperature is lowered.

Early warning signs

Warning signs of cold stress include:

  • feeling cold and shivering
  • loss of feeling or tingling in fingers and toes
  • trouble moving fingers, hands and toes (trouble doing tasks)
  • frost nip (outermost layers of skin turn white)
  • "unusual –umbles", such as stumbles, mumbles, fumbles and grumbles

Worsening symptoms

  • extreme shivering, and then shivering stops
  • impaired coordination
  • confusion
  • frost bite (skin freezes deeply, turning blue or red)
  • loss of consciousness

Severe cold stress can lead to hypothermia, which can result in death.

How to stay warm

  • wear layered and insulating clothing
  • cover exposed skin
  • stay in the sun
  • take breaks inside
  • keep footwear dry
  • keep moving to generate body heat (but avoid sweating)

What employers can do

When working in cold temperatures you should expect the following:

  • on-site heaters or heated shelter
  • work/warm-up schedule
  • a flexible pace where workers can take extra breaks if needed
  • shield workers from drafts or winds as much as possible
  • a buddy system so no one works alone
  • adjustment periods before assigning a full work schedule
  • do hazard assessment, put controls in place for protection and educate workers on the hazards of working in the cold

Working in extreme heat

Your body needs time to adapt to working in hot weather. This process can take 4 to 7 working days, but can vary with every individual. You should slowly increase the time spent working outdoors during hot weather to make sure you can work safely.

Early warning signs

Warning signs of heat stress include:

  • irritability
  • fainting, dizziness and fatigue
  • dehydration
  • headache and confusion
  • muscle cramps
  • heavy sweating
  • heat rash

Worsening symptoms

  • sweating may stop
  • hot and dry skin
  • changes to pulse rate
  • severe muscle cramps
  • severe headache
  • exhaustion
  • trouble breathing

Untreated heat stress can progress to heat stroke, which is life-threatening.

How to avoid overheating

  • take breaks if needed
  • drink lots of water (1 cup of water every 15 minutes)
  • wear clothing and protective equipment designed to reduce heat stress
  • minimize physical activity in hot environments
  • know the signs of heat stress

What employers can do

When working in hot temperatures you should expect the following:

  • use a work-rest schedule
  • change the work location to a cooler shaded area
  • create a cooling station where workers can rest
  • allow workers to adapt to the temperature
  • schedule more physically demanding jobs for cooler times of the day
  • providing plenty of cool drinking water
  • do a hazard assessment, put controls in place for protection and educate workers on hazards of working in the heat


You can print or share infographics related to working in the cold or heat.


Connect with OHS:

Phone: 780-415-8690 (Edmonton)
Toll free: 1-866-415-8690 
TTY: 780-427-9999 (Edmonton)
TTY: 1-800-232-7215

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