Cold Stress and Winter Safety

Cold Stress and Winter Safety

This week several Canadian meteorologists  and climatologists released their predictions for the winter season, and the theme was consistent, we are expecting a traditional Canadian winter ahead. While their forecast may fail to materialize we are alerted to the reality that some Canadian workers will experience cold stress hazards  while on the job, affecting performance and safety.

Workers who are required to work in cold environments may be at risk of cold-stress. Whenever temperatures drop decidedly below normal, and as wind speed increases, heat can more rapidly leave your body. The temperatures do not need to be extreme for cold stress to occur. Repeated exposures and moisture are also critical variables in the development of stress situations. These weather-related conditions may lead to serious health problems such as:

Hypothermia  is the most common form of cold stress and occurs when the body begins to lose heat faster than it can be metabolically produced. Prolonged exposure to cold will eventually use up your body's stored energy. The result is an abnormally low body temperature. A body temperature that is too low affects the brain, making the victim unable to think clearly or move well. This makes hypothermia particularly dangerous because a worker may not know it is happening and will not be able to do anything about it.

Frostbite is an injury to the body that is caused by the freezing of skin and underlying tissues. Frostbite causes a loss of feeling and color in the affected areas. It most often affects the nose, ears, cheeks, chin, fingers, or toes. Frostbite can permanently damage body tissues, and severe cases can lead to amputation. In extremely cold temperatures, the risk of frostbite is increased in workers with reduced blood circulation, and among workers who are not dressed properly.

Trench foot, also known as immersion foot, is an injury to the feet resulting from prolonged exposure to wet and cold conditions. Trench foot can occur at temperatures as high as 15oC if the feet are constantly wet. Injury occurs because wet feet lose heat 25-times faster than dry feet. Therefore, to prevent heat loss, the body constricts blood vessels to shut down circulation in the feet. Skin tissue begins to die because of lack of oxygen and nutrients and due to the build-up of toxic products.

Chilblains are caused by the repeated exposure of skin to temperatures just above freezing to as high as 15oC. The cold exposure causes damage to the capillary beds (small blood vessels) in the skin. The damage can become permanent and result in itching and redness that occurs with additional exposure. The redness and itching typically occur on the cheeks, ears, fingers, and toes.

Immersion Hypothermia develops much more quickly than standard hypothermia because water conducts heat away from the body 25 times faster than air.

Working in cold environments including unheated indoor areas, require employers to take measures to understand the work conditions and how to prevent cold-stress related injuries from occurring include but are not limited to:

Scheduling of work to avoid extremely cold days, or performing work during the warmest part of the day. Take into consideration the additional factor of precipitation.

Erect enclosures or barriers around the work to eliminate the negative effects of wind speed and precipitation. Heat the enclosure where possible.

Schedule additional time or the number of workers to complete the task. Allow for additional breaks and rotation of personnel to complete the work. This will reduce the physical demands on the workers. Provide warm areas and or warm liquids for the workers.

Monitor the conditions and workers who are at risk to cold stress injuries. Using the ACGIH cold stress indices to set work schedules, and observe workers for signs and symptoms of cold stress.

Workers should be outfitted with appropriate and layered clothing. Workers not provided cold weather clothing by the company employers need to ensure all workers are properly protected with several layers of loose-fitting clothing to provide adequate insulation. No tight-fitting clothing or boots.

Boots should be waterproof and insulated, gloves suitable for the task used, as well as insulated gloves for non-work time to retain heat. If the workers may get wet due to the conditions, or level of exertions, extra clothes may be needed.

Always ensure the workers are properly trained on the hazards, controls and work practices to protect themselves from the effects of cold weather. Workers in cold environments should monitor their condition and that of their co-workers.

Regardless of the accuracy of the weathermen to predict our upcoming winter, workers will be required to work in environments that may have elevated risks to cold stress. Proactive planning, procedures, and worker training will greatly reduce the chances of cold stress-related illnesses.

"In cold or freezing conditions, the worst thing you can do is let yourself get sweaty."

- Les Stroud “Survivorman”