Temps down, heads up: Working Safely in the Cold

Intro: This podcast is brought to you by the Canadian Centre for Occupational Health and Safety.

CCOHS is situated upon the traditional territories of the Erie, Neutral, Huron-Wendat, Haudenosaunee and Mississaugas. This land is covered by the Dish With One Spoon Wampum Belt Covenant, an agreement between the Haudenosaunee and Anishinabek to share and care for the resources around the Great Lakes. We further acknowledge that this land is covered by the Between the Lakes Purchase, 1792, between the Crown and the Mississaugas of the Credit First Nation.

Ashley: Hello and welcome to Health and Safety To Go, a CCOHS podcast. With winter upon us and colder temperatures on the horizon for much of Canada, a lot of us might find ourselves thinking about people who are working outdoors – wondering what that’s like and how they do it. Well, as it turns out, there’s a lot more to working safely in the cold than bundling up in layers. Right, Chris?

Chris: That’s right, Ashley. It’s important to understand the hazards that come along with working in the cold. Workers need to be able to recognize the signs of cold-stress injuries, so thorough training should be completed before sending any worker into cold temperatures.

Ashley: Let’s talk a little bit about those cold temperatures first. A good place to start is the three primary factors that affect how we react to the cold: air temperature, air movement (wind speed), and humidity. In wintertime, we also hear a lot about “wind chill”. What exactly does that mean?

Chris: At any temperature, you feel colder as the wind speed increases. The combined effect of cold air and wind speed is expressed simply as the “wind chill” temperature in degrees Celsius or Fahrenheit. It’s not unlike how “humidex” is used in the summer to describe how humidity affects our perception of temperature. Wind chill temperature can be used as a general guideline for deciding clothing requirements and the possible health effects of the cold.

Ashley: And how cold is too cold for workers to do their jobs safely?

Chris: Some jurisdictions have adopted occupational exposure limits, such as the use of the Threshold Limit Values® for cold stress published by the American Conference of Govermental Hygienists (ACGIH). These exposure limits suggest a work-warming schedule when the wind chill temperature is at or below -7°C (19.4°F), and that heated warming shelters (such as tents, cabins, restrooms, etc.) should be made available nearby. Where there are no maximum or minimum exposure limits, workplaces can follow these limits, or other guidelines to protect the health and safety of workers who may be exposed to the cold.

Ashley: So, what can be done to minimize the risk of cold injury?

Chris: Proper equipment design, safe work practices and appropriate clothing all play a big role. The key is to stay warm and dry. Dress in layers of warm clothing, with an outer layer that is wind-resistant. Wear a hat, mittens or insulated gloves, a scarf, neck tube or face mask, and insulated, waterproof footwear. Staying active can help keep the body temperature up.

Ashley: For work below the freezing point, metal handles and bars should be covered by thermal insulating material. Ideally, machines and tools should be designed so that they can be operated without having to remove mittens or gloves. Safe work practices include strategies such as always working with a buddy, monitoring the temperature and rate of air movement, and taking regular breaks to warm up in heated shelters.

Chris: Protective clothing needs to be worn when it’s below 4°C. It should suit the temperature, weather conditions, the level and length of the activity, and how the job is designed. The goal here is to regulate the amount of heat and sweat you generate so you can stay dry and warm. If the work pace is too fast or a worker’s clothing is‘nt properly selected, they could sweat too much and the clothing next to their body will become wet. The insulating ability of clothing decreases dramatically when it is wet.   

Ashley: So Chris, let’s say you and I are working together and it’s below zero. What kinds of cold injury signs are we looking for in each other?

Chris: If you have redness, tingling, itching, pain, swelling in your legs, feet and hands, or blisters, that could be a sign of an injury such as chilblain, immersion foot or trenchfoot. Chillblains are usually mild in nature and resolve mostly on their own. Immersion foot and trench foot are the result of having wet feet for a prolonged period of time, and can result in gangrene or other infections.

Ashley: Then there are freezing injuries, which include windburn, frostnip and frostbite. Windburn occurs when the top layer of oil on our skin is stripped away by the wind, causing dryness, redness, itching and flaking. Frostnip occurs when ears, noses, cheeks, fingers, or toes are exposed to the cold and the top layers of the skin freeze, turning paler than the area around it.  You may feel pain or stinging, followed by numbness.
At the frostbite stage, the skin may look waxy and feel colder than the area around it. It may also be harder to the touch. Blood vessels may be severely and permanently damaged, and blood circulation may stop. Inflammation and blisters may also appear.  If we see any signs of freezing injuries or frostbite, we need to talk to our supervisor.  We might also ask for first aid. Frostbitten skin is highly susceptible to infection or gangrene.

Chris: An important rule for staying safe while working in the cold is: never ignore numbness. If the area feels numb or tingly, take steps to warm it right away – if you cannot go to a warm location, you can put your hands under your armpits, or pull your arms inside of your jacket for more direct contact with your body.
If a co-worker is showing signs of frostbite or describes symptoms of immersion or trench foot, get them to a warm area as quickly as possible. Remove any wet clothing, and gently loosen or remove constricting clothing. Warm them by wrapping them in blankets or by putting on dry clothing. Cover the head and neck and warm the person slowly. DO NOT rub the area.

Ashley: Hypothermia is among the most severe cold-stress injuries and happens when a person is exposed to intense cold without adequate clothing. A feeling of cold is followed by pain in the exposed body parts, which leads to muscular weakness and drowsiness. You can think of these symptoms as “stumbles, mumbles, and fumbles”.  Hypothermia is a medical emergency, so when you see a co-worker showing these symptoms, it’s important to get help immediately. Move the person out of the cold, insulate them, and handle them gently until help arrives.

Chris: Well as you mentioned, Ashley, there’s a lot more to working safely in the cold than wearing layers.

Ashley: That’s right Chris, and there are a lot more resources on the topic on our website, CCOHS.ca.

Thanks for listening!