The Cold Is as Dangerous as the Heat


Most employers are aware of their duty to protect workers from heat stress. But the extreme cold can be just as dangerous. For example, exposure to the cold can cause hypothermia, which can be fatal. So as winter approaches, it’s important to ensure that you have measures in place to protect workers from hypothermia, especially those who work outside.

Hypothermia 101

According to the Canada Safety Council, hypothermia, sometimes called exposure, occurs when the body can no longer produce more heat than it’s losing. The body’s internal temperature then drops below 35° C or 95 ºF.

Wind, wet and cold are the key factors that lead to hypothermia. Wind can chill the body as air moves over it. Water rapidly absorbs body heat. In fact, wet clothing is a common cause of hypothermia and casualties in lakes and rivers are often due to hypothermia, not drowning.

Cold air cools down the body—but it doesn’t have to be frigid. Hypothermia can happen at under 10° C, so it’s a threat even with above-average winter temperatures.

How to Protect Workers

To protect workers from hypothermia, first make sure they know the symptoms:

Initial Signs (Mild Hypothermia)

  • Bouts of shivering
  • Grogginess and muddled thinking
  • Breathing and pulse are normal

Danger Signs of Worsening Hypothermia (Moderate Hypothermia)

  • Violent shivering or shivering stops
  • Inability to think and pay attention
  • Slow, shallow breathing
  • Slow, weak pulse

Signs of Severe Hypothermia

  • Shivering has stopped
  • Unconsciousness
  • Little or no breathing
  • Weak, irregular or non-existent pulse


The Canada Safety Council recommends that anyone working outside prepare themselves from hypothermia by doing the following:

  • Wear a warm hat. Most body heat is lost through the head.
  • Wear adequate clothing. Proper clothing and protection trap the warm air around the body. The key is to keep warm and dry.
  • Wear layered clothing. Proper layers allow warm air to stay trapped but don’t trap perspiration next to the skin. The first layer lets the skin breathe. Underwear, socks and glove liners of polypropylene or knitted silk let perspiration escape from next to the skin. The second layer absorbs perspiration without allowing heat to escape. Wool is ideal because it stays warm even when wet. The third layer traps heat in and keeps water or dampness out. A quilted coat filled with down or a lightweight microfibre is ideal. If it’s not waterproof, wear a water- resistant shell or windbreaker.
  • Protect your feet and hands. Wear loose waterproof boots. If the boots have felt liners, carry an extra pair to replace damp ones. Mittens warm the hands more effectively than gloves. Carry an extra pair of these, too.
  • Prevent dehydration and exhaustion, which can lead to hypothermia. Drink plenty of non-alcoholic fluids. Pace yourself when doing vigorous activity.
  • Stay fit through good physical conditioning and good nutrition. People who are fit are less susceptible to hypothermia. And don’t let yourself become weakened through fatigue.
  • Try to stay in a heated environment, but not so hot as to cause excessive sweating. You risk hypothermia when you try to cool down by leaving a hot environment for a cool one.
  • Eat high energy food, such as nuts and raisins.
  • Avoid alcohol, coffee, tea and tobacco. They can cause heat loss.
  • If you’re traveling (on the road or in the wilderness), carry emergency supplies.

What to Do for Suspected Hypothermia

Finally, make sure that workers know what to do if they suspect that a co-worker has hypothermia. For example, they should:

  • Take measures to prevent further heat loss and get medical help as quickly as possible.
  • Continue the warming efforts even if there’s little or no pulse or heartbeat. Severe hypothermia can be mistaken for death.
  • Move the worker to a dry, warm location if possible or provide protection from the wind. Keep the person horizontal.
  • If you can’t replace wet clothes with dry ones, cover the wet clothes with warm dry clothing or blankets and place something warm and dry under the worker. If the worker’s conscious, supply a warm drink, but avoid alcohol and caffeine.

OHS Insider Resources

Click here for more information on protecting workers from cold stress through a cold exposure control plan, including a model plan.