Workers who are exposed to extreme cold or work in cold environments are at risk for cold stress. The effects of cold stress are more hazardous in wet and windy conditions. As temperatures drop and wind speed increases, heat can rapidly leave the body, leading to serious health problems such as dehydration, numbness, trench foot, frostbite and hypothermia. In short, Low Temps + Wetness + Windy Conditions = Cold Stress.
In cold environments, most of the body’s energy is used to maintain our internal temperature. During prolonged exposures, the body shifts blood flow away from our extremities (e.g., hands, feet, arms, ears and legs) and outer skin to our core (e.g., chest and abdomen), causing our extremities to cool rapidly. It is stressful on the body to continue working in such conditions and the consequences can be deadly.
One of the most important ways to prevent cold stress is to wear clothing that protects against wind, keeps the body dry and insulates against cold weather. This consists of wearing the right number of layers as well as appropriate cold weather accessories based on environmental conditions. The National Oceanic and Atmospheric Administration recommends the following:
Many outdoor exercise and apparel companies promote the following dress for outdoor cold weather activities:
- Foundation layer: The first layer should be a base layer that wicks moisture away from the body and insulates.
- Mid-layer: A second and, when necessary, additional layer that insulates, yet is flexible and loose enough to trap body heat.
- Outer shell layer: should be waterproof, windproof, yet breathable and tough
- Extremities: accessories such as hats, hoods, scarves, gloves and socks help keep body heat in. Insulated hats and hoods can block wind from the face and help scarves protect the neck. Leather or insulated gloves are a better physical barrier than cotton.
Another important factor for preventing cold stress while working outdoors is staying hydrated and protecting your skin. This can be done by:
- Applying lip balm (preferably a non-petroleum balm with natural oils) to help prevent dry and cracked lips.
- Wearing sunscreen. Sunscreen is often associated with warm weather, but the sun’s damaging ultraviolet rays reflect off snow and water, increasing your exposure.
- Staying hydrated by drinking plenty of warm liquids and water and eating nutritious, moisture-rich foods such as fruit and vegetables.
Employers Protecting Workers
Employers should protect workers from cold stress by:
- Making sure workers recognize the environmental and workplace conditions that may be dangerous (e.g., cold temperatures, wet conditions and wind)
- Learning the signs and symptoms of cold-induced illnesses and injuries and how to help workers experiencing such symptoms
- Training workers about preventing cold stress
- Making sure workers in extreme conditions take frequent breaks in warm, dry shelters to warm up
- Scheduling work during the warmest part of the day
- Making use of radiant heaters, indoor heated rest areas or barriers to protect workers from the wind
- Allowing new employees to acclimate to cold temperatures
- Encouraging employees to warm up before work begins by incorporating stretch and flex exercises at the beginning of each shift.
Risks of Prolonged Cold Exposure
Frostnip – The mildest form of freezing injury, it occurs when the top layers of skin freeze (usually ear lobes, noses, cheeks, fingers or toes). The affected area turns white and may feel numb; the top layer of skin feels hard but the deeper tissue still feels normal (soft).
Frostbite – Freezing of the deep layers of skin (usually fingers, ears, nose, hands, feet, toes). Skin turns pale, numb and hard.
Hypothermia – Body loses heat faster than it can produce it. It is sneaky and often kills before people are aware of the danger. Symptoms include shivering, poor body coordination, being groggy or having slurred speech and the inability to think or pay attention.
[April R. Dorsey is the LHSFNA’s Safety & Health Specialist.]