Employees are exposed to cold when they work outdoors or in refrigerated indoor environments. Workers in construction, forestry, fishing, utilities and food processing and storage are most often affected. Working for prolonged periods in cold environments causes the body to decrease blood flow to the skin. The result can be cold stress. Some danger signs include irritability, changes in skin colour, disorientation and drowsiness.
Canadian provinces and territories require employers to identify cold stress as a workplace hazard and take specific measures to control, prevent and minimize injuries related to cold stress. .
The loss of body heat can cause inner body temperatures to fall to dangerously low levels. There are various risks to working in the cold, but employers and supervisors should especially be aware of two conditions that can be harmful to workers:
- Frostbite is the freezing of body tissues. The fingers, toes, ears and nose are particularly vulnerable. Skin freezes at about -1 degree Celsius. If it is windy, this can happen quickly. Exposed flesh can freeze in about one minute at -10 degrees with a wind of 12 kilometres per hour. Frostbite can also be caused by contact with cold objects. Symptoms of frostbite include: a pale appearance in fingers, toes, cheeks, noses and ears; waxy looking skin; and a loss of feeling in the extremities.
- Hypothermia results when the body mechanisms can no longer maintain internal temperature above 35 degrees. Blood vessel constriction is no longer adequate to retain heat and shivering becomes the only mechanism available. Early symptoms of hypothermia are uncontrollable shivering, blue lips and fingers, and poor coordination. Later symptoms include slow speech, memory lapses, frequent stumbling, drowsiness, heart rate slowdown and exhaustion.
In Ontario, Alberta, Manitoba, Quebec and Nova Scotia, there are no limits on minimum temperature specified for outdoor work in cold weather. However, employers are encouraged, and sometimes required by law, to implement engineering controls to maintain thermal comfort. If the use of engineering controls is not feasible, employers must use a combination of administrative controls and protective clothing and equipment to manage the issue, including warning and educating employees about the dangers of cold stress, how to recognize and treat the various signs and symptoms of frostbite and hypothermia. Your cold stress exposure plan must fit the specific needs and circumstance of your workplace, industry, facility, work processes and the legal requirements of your province.
British Columbia, Saskatchewan, New Brunswick, Newfoundland and Labrador, Prince Edward Island, Yukon, Nunavut, the Northwest Territories and the Federal jurisdiction require employers to identify cold stress as a workplace hazard and take specific measures to control, prevent and minimize cold stress related injuries. The extent of applicable measures varies depending on the jurisdiction. For example, British Columbia specifies thermal conditions that could cause a worker’s core body temperature to fall below 36°C (96.8°F) as being a hazard that requires control measures to be implemented.
In provinces and territories with no limits in minimum temperature specified for outdoor work in cold weather, follow the threshold limit values for protection against cold stress as well as the work-warming regimen for cold and other advice found from pages 125 to 140 of the American Conference of Governmental Industrial Hygienists’ publication 1997 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices.
Employers should ensure that workers and supervisors who work outdoors in the cold weather are trained in how to avoid frostbite and hypothermia, and how to assist a person who exhibits the signs of these conditions. Workers should be trained in understanding the effects of cold temperatures, wind chills and touching cold objects. They should also be trained in using proper protective clothing.
Employers are recommended to do the following in order to avoid frostbite and hypothermia:
- Have the workers dress in layers-first a layer of synthetic fibres to wick moisture away from the body, then a layer or two of wool or fleece to insulate, and then a layer of nylon to protect from the wind
- Have the workers wear insulated head coverings, gloves and boots
- Ensure warm clothing, head coverings, gloves and boots are not too tight, in order to prevent the constriction of blood vessels
- Allow some type of periodic physical activity such as stretching and warming exercises so workers can generate body heat
- Shield the work area from windy conditions and provide a warm shelter
- Limit worker exposure to cold through suitable work/rest schedules
- Use a buddy system to ensure that the workers are constantly monitoring each other and are safe
- Properly assess the environment by considering air temperature, wind speed, humidity and the temperature of objects with which the workers make contact
- Increase the length and frequency of rest breaks as wind chill rises and air temperature drops
- Ensure that workers are sufficiently medically fit to work in excessive cold-acute exertion in cold temperatures can constrict blood vessels in the heart, which can negatively impact those with heart problems
- Ensure that there is communication with other workers and there are backups when workers work in isolated cold environments
- Provide warm sweet drinks and high-caloric foods
- Ensure that workers avoid using alcohol, coffee or cigarettes that constrict blood flow to the skin and contribute to the problems
Where there are signs of frostbite or hypothermia, employers are recommended to do the following:
- Move the worker to shelter
- Begin warming the person slowly, beginning with the neck, abdomen and chest (warming the arms and legs first can force cold blood to circulate to the heart and cause heart failure)
- Seek immediate medical assistance
- If the worker is conscious, give the worker warm sweet drinks
First Reference Human Resources and Compliance Managing Editor