Working safely in cold weather

Cold weather work is routine across much of Canada, which makes it easy to underestimate. Cold stress can cause frostbite and hypothermia, and it also makes every other hazard worse: slips on ice, stiff hands on tools, reduced attention, and equipment that behaves differently. Employers must assess cold as a hazard and put controls in place, just like any other.

How the body loses heat

The body loses heat faster when air temperature is low, when wind carries heat away, when clothing or skin is wet, and when a worker is in contact with cold surfaces such as metal, snow or the ground. Wind chill expresses the combined effect of cold and wind on exposed skin, and Environment and Climate Change Canada publishes wind chill values and frostbite risk in its forecasts. Physical exertion produces heat, but sweating then wets clothing, and the worker cools quickly once they stop.

Cold injuries and illness

Frostbite

Freezing of skin and underlying tissue, most often on fingers, toes, ears, nose and cheeks. Early signs are numbness, a white or greyish-yellow waxy look, and firm skin. Workers often cannot feel it happening, so watching each other matters.

Hypothermia

A drop in core body temperature. Early signs include shivering, fatigue, clumsiness and confusion. As it worsens, shivering may stop, speech becomes slurred and judgment fails. Severe hypothermia is a medical emergency.

Non-freezing injuries

Prolonged exposure to cold and wet conditions without freezing can damage feet and hands. Chilblains and immersion-type injuries are less dramatic than frostbite but can be lasting.

Planning cold weather work

Include cold in your hazard assessment for outdoor work, unheated buildings, freezers and cold storage, and vehicle travel. Consider:

• Expected temperature and wind chill, and how they change through the shift.
• How strenuous the work is, and whether it involves periods of standing still.
• Whether workers will get wet from rain, snow, sweat or the process.
• Access to warm-up shelters, hot drinks and dry clothing.
• How quickly an injured worker could be moved to a warm place and to medical care.
• Remote locations and travel risk. See working alone safely.

Many employers use a warm-up and work schedule, such as the one published by ACGIH as part of its cold stress guidance and adopted or referenced by several Canadian jurisdictions, which sets maximum work periods and break frequency as wind chill drops. Check what your province requires or recommends.

Controls

Engineering

• Heated shelters or vehicles near the work area.
• Windbreaks and enclosures around work areas, with safe ventilation if heaters are used.
• Insulated handles on tools and equipment.
• Heated or temporary enclosures for concrete, roofing or other work that must continue.

Administrative

• Schedule outdoor work for the warmer part of the day where possible.
• Build in regular warm-up breaks, more frequent as conditions worsen.
• Use a buddy system so workers watch each other for warning signs.
• Allow new workers and those returning from time away to get used to the cold gradually.
• Set a point at which non-essential outdoor work stops.
• Train workers and supervisors to recognize and respond to cold injury.

Clothing and PPE

• Layers: a moisture-wicking base, an insulating middle layer, and a wind and water-resistant outer layer.
• Hard hat liners that keep the hat's protection intact, and face protection in high wind chill.
• Insulated, waterproof safety footwear with good traction, and ice cleats where suitable.
• Gloves or mitts that balance warmth with the dexterity the task needs, with spares to swap when wet.

See choosing the right PPE for how cold-weather gear fits with protective equipment standards.

A typical cold day, planned well

A mechanical crew is scheduled to replace a rooftop exhaust fan in January. The forecast calls for a bitterly cold, windy morning with milder air in the afternoon. The supervisor's plan for the day might look like this:

1. Check the forecast and wind chill the evening before and again at the start of the shift, and compare them with the company's warm-up schedule.
2. Re-sequence the job. Prep work, such as staging parts and pre-assembling the curb adaptor, is done indoors in the morning. The lift and rooftop work move to the afternoon.
3. Set up shelter. A heated space is arranged at the top of the roof access stair, so warm-up breaks do not mean a long walk down.
4. Brief the crew on the break schedule, buddy checks for frostbite on faces and fingers, and the plan for icy roof surfaces and edge protection.
5. Kit check. Spare dry gloves and liners, hard hat liners, face protection, and ice cleats where they are safe to use on the roof surface.
6. Watch and adjust. The supervisor checks in at each break. When the wind picks up more than forecast, rooftop work stops early and resumes the next day.

A supervisor's daily cold-weather check

• Forecast and wind chill reviewed, and the schedule adjusted
• Warm-up shelter available, heated and safely ventilated
• Warm drinks and a place to change out of wet clothing
• Crew paired up and briefed on warning signs
• Walkways, stairs and ladders cleared of snow and ice, and sanded or salted
• Gas detectors, batteries and other equipment within their rated temperature range
• Plan for moving an injured worker to warmth and medical care

Other winter hazards

• Slips and falls on ice and snow, especially on stairs, ladders and roofs.
• Snow and ice on roofs adding load and falling from edges. See snow loads on roofs.
• Carbon monoxide from heaters and engines in enclosed or tarped areas. Use detectors and ventilation.
• Equipment such as batteries, hydraulics and gas detectors behaving differently in the cold. Follow manufacturers' temperature ranges.
• Short daylight reducing visibility for traffic and equipment.

How ehZee can help

ehZee helps employers include cold weather work in their hazard assessments, write cold stress procedures and train supervisors, as part of a wider safety program. See safety program development and review.

Common questions