When workers are exposed to cold environments, they may experience cold stress, which occurs when the body is unable to warm itself. The risk can become severe if a worker’s core body temperature falls below 36°C.
Section 4.12 of Manitoba’s Workplace Safety and Health Regulation (the Regulation) notes that when a worker is exposed to cold, it may create a risk to the worker’s safety or health. The employer must implement safe work procedures and control measures and provide the worker with information, instruction and training on cold stress and precautions to avoid injury.
When assessing workers’ exposure to cold, the threshold limit values for thermal stress established by the American Conference of Governmental Industrial Hygienists in its publication, 2019 Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices, must be followed.
Cold stress can be experienced in both indoor and outdoor work environments. For example, indoor workers who work in refrigeration rooms or unheated buildings can be exposed to cold stress if not properly protected. Remember, it doesn’t take below-zero temperatures for a worker to experience cold stress.
Industries where the potential for cold stress exists include:
When assessing workers’ exposure to cold and their risk of experiencing cold stress, it is important to consider the following factors:
When exposed to cold, the body tries to reduce heat loss by redirecting blood flow from the extremities to the core. The body also increases metabolic heat output by shivering. If cold exposure continues and workers are not properly protected, it may result in a cold-related injury. This includes the following:
Suppose workers are exposed to cold stress during their job duties. In that case, Part 4.12 of the Regulation notes that the employer must provide workers with information, instruction and training on cold stress. This should include:
In addition to training, it is recommended that your workplace develop and bring in a thermal stress management program. Though this is not a requirement of the legislation, it is a best practice that will help mitigate the risk of your workforce being exposed to cold stress.
Employing a buddy system with your co-worker or supervisor is a great way to mitigate the risk of cold injury as part of your strategy to reduce the risk of exposure to cold stress. Pairing up when working in the cold helps timely identify signs and symptoms of cold stress and ensures first aid is provided when appropriate. Ensure workers know the reporting procedures and actions they must take when they identify co-workers showing signs and symptoms of cold stress.
If workers are not used to cold and will be performing their duties within these environments, it is important for the employer to allow time for the worker to acclimatize to that specific working environment. Acclimatization can be defined as the gradual physiological adaptation that increases an individual’s ability to tolerate thermal stress, which occurs over time. Workers who have not been properly acclimatized to their work environment may experience cold stress immediately.
When working in cold environments, workers should take scheduled rest breaks and be encouraged to use warm-up shelters as needed, especially as soon as they start showing early signs and symptoms of cold stress. Workers should be reminded of the shelter location, and when entering a warm-up shelter, they should remove layers as appropriate to prevent sweating.
When working outdoors, it is important to be mindful of the weather, especially windchill and precipitation values. When looking at controls, windchill values will dictate clothing requirements to maintain core body temperatures above 36°C. For weather information, check your local forecast before starting work.
Work rate focuses on the intensity of work or the activity level, which is the energy required to complete a task. It is important to set the work rate so that the worker is able to stay warm without causing them to sweat and increase their risk of cold stress. It is also important to note that the opposite can be an issue. Prolonged standing, sitting or contact with cold surfaces can also affect a worker’s ability to stay warm.
The type and amount of layers of clothing required to keep workers comfortable when working in cold environments is dependent on a worker’s metabolic rate, work rate and wind chill. For example, if the worker is performing sedentary work in cold environments, where they are seated or standing in a position for long periods of time, they may require a higher insulation factor and additional layers to keep warm. This may include a warm jacket, long-sleeved sweater, toque, mitts and facemask. However, if they perform hard work (carrying a 40-pound load), they may require less insulation, such as a light jacket, long-sleeved sweater and gloves. If the work process involves increased hand dexterity, gloves may be required. Mitts have a higher insulation factor than gloves but provide less dexterity. If workers will be in cold environments where gloves are required, increased warm-up periods or breaks should be considered.
Remember, it is always important to wear a base layer that will wick away sweat and dress in layers to adjust your insulation value based on the working conditions. Ensure your clothing is not too tight, as this can restrict blood flow and decrease your body’s heat production.
For additional information on clothing requirements, visit the Working in cold weather safety topic.
The Workers Compensation Board of Manitoba serves workers and employers through a no-fault insurance system integral to the Manitoba economy. Funded collectively by employers, the WCB promotes safe and healthy workplaces, facilitates recovery and return to work, delivers compassionate and supportive compensation services to workers and employers, and ensures responsible stewardship of Manitoba's workers' compensation system.
