As we say goodbye to the warm, sunny weather we don’t have much time to prepare ourselves for the harsh Ontario winter that is about to come. For some workers, seasonal work doesn’t only mean for the warm months. Many labourers are required to work outdoors in cold environments; anyone working in the cold environment may be at risk of cold stress.
What is it?
Ontario is known for its extremely cold winter and by the sounds of it, this upcoming winter is going to be one of the worst. With the windshield effects, temperatures have been known to reach close to –40ºC or colder some days. The general population has definitely complained about the extreme temperatures in the past years, but it is particularly problematic to workers that are directly working within the cold.
During a typical work day, construction workers, farmers, foresters (to name a few) have to deal with cold stress (this article also applies to workers that work within cold storage facilities, meat packing plants etc.). When dealing with cold stress, workers are more likely to experience localized body injuries (such as frost bite) and lose the ability to maintain core body temperatures (such as hypothermia). Therefore, it is extremely important that workers take all necessary precautions when dealing with cold stress.
The role of cold stress on the body
As soon as the body detects cold stress, the body sets off two defense mechanisms: peripheral vasoconstriction and involuntary muscular contractions. When the body detects the cold, the peripheral circulation undergoes vasoconstriction and decreases blood flow to the skin as a mechanism to conserving body heat and minimizing heat loss. As well, the body tries to maintain thermal equilibrium by increasing heat production via involuntary muscular contractions—involuntary muscular contractions that we commonly refer to as “shivering.”
Two major health concerns associated with cold stress is hypothermia and frostbite.
Hypothermia is usually experienced by individuals working in the cold for a long period of time but also for workers performing physical exertion, thus resulting in sweating and a rapid decrease in heat loss. As discussed, coping mechanisms are activated, such as peripheral vasoconstriction and involuntary muscular contractions. The worker begins to experience extreme fatigue and exhaustion, which causes vasodilation and short–term heat loss. Ultimately, the worker’s central nervous system is disturbed and could potentially cause the worker to collapse, fall into coma or even die.
On the other hand, although workers experiencing cold stress are at a higher risk of developing frost bite, any individual within the extreme cold can experience frost bite. Frostbite occurs when the human tissue freezes, or more specifically, the fluid around the body tissue starts to freeze. As a result, there is damage to and a loss of human tissue after the tissue dies. Damage can be temporary (leading to recovery) or permanent. Skin starts to freeze at -1ºC and the extent of damage is directly related to the depth of frostbite. Body parts that are the most vulnerable to frostbite are the extremities, such as the nose, cheeks, ears, fingers and toes.
What can we do about it?
There are quite a few controls that employers can implement. Ideally, the most effective controls are known as engineering controls, which control the cold stress hazard at the source. An example of an engineering control includes general spot heating of the workplace (with a radiant or convection heater). Unfortunately, engineering controls are not always feasible and in these situations, administrative controls can be implemented. These controls isolate the cold stress hazard along the process and such examples include the scheduling of periodic work breaks, performing tasks within the cold during warmer parts throughout the day, training workers on how to deal with cold stress or by rotating the workers who work within the cold environment. Again, administrative controls may not be feasible in some situations and therefore, personal protective equipment must be worn; this is the most common control measure used in managing cold stress. Workers must wear warm, insulated clothing that is able to breathe, allows sweat to evaporate and keep the body dry.
Cold stress is a major health concern for workers working within the cold environment. Employers, managers/supervisors, and workers should be fully aware of the potential health effects that cold stress may cause and how to prevent them. By applying proper and feasible control measures (engineering, administrative or personal protective equipment) suitable for the workplace, cold stress can be managed.
Stay warm this winter!