Winter is underway and depending on where your construction company operates, you’re probably seeing colder temperatures, wet conditions, and frozen precipitation on the job site. Though worker safety should always be your first priority, winter brings a unique set of circumstances. Be aware that slips and falls on icy surfaces are not the only possible sources of injury. It’s time to take specific measures to protect your workers from cold stress injuries.

What is Cold Stress?

Cold stress occurs when exposure to low temperatures, especially in windy and wet conditions, causes the body to lose heat rapidly, first externally, then internally. Because the body’s natural defense against severe cold is to keep the core warm to preserve vital functions, blood flow is diverted from the skin and limbs to the core. When the skin and extremities cool rapidly, frostbite and hypothermia can result.

Use the National Weather Service Wind Chill Calculator to help predict wind chill factors and their effects on the body based on air temperature and wind speed.


Exposed skin can freeze and die. Hands, feet and exposed facial skin are most at risk. Frostbite may present first as red patches of skin that sting, become numb and later turn grey or white and then, in severe cases, blue or black. Once numbness sets in, the individual may be unaware of the extent of the damage until it is too late. Severe tissue damage can be permanent and result in the amputation of the affected extremities.


When the body is no longer able to warm itself, the core temperature drops. Symptoms of hypothermia range from shivering to confusion slowed heart rate, dilated pupils, and unconsciousness. Severe hypothermia can cause death.

Individuals at most risk include those with preexisting health conditions, exhaustion, prolonged exposure to windy and or wet conditions, and those who are improperly dressed for the weather.

Trench or Immersion Foot

When workers have cold, wet feet for a prolonged period of time, the blood vessels in the feet constrict. If not treated, the skin of the feet can die and slough off. Symptoms include redness, swelling, numbness, and the formation of blisters.

Preventing Cold Stress

  • Hold meetings with your workers to be sure they are prepared for the conditions they will experience and educate them about the sign of cold stress.
  • Make sure your workers are properly dressed and if possible, provide them with winter gear like insulated, waterproof boots, gloves, hats, and knit face masks. Because moisture from perspiration causes cold stress too, it’s best to dress in 3 layers. For the first layer, choose moisture-wicking fabrics that help keep the skin dry. The second layer should be a wool or synthetic fabric for insulation. The outer layer should protect against wind and precipitation but be ventilated to allow moisture to escape.
  • Encourage your employees to bring extra clothing, socks, and gloves to change into in case their clothing becomes wet.
  • Provide windbreaks and places out of the weather where workers can warm up. Schedule regular breaks. Use tarps to create sheltered areas and consider renting heaters and or portable buildings to use on-site for breaks.
  • Our bodies have to work hard to stay warm and they burn calories faster. Provide plenty of warm, sugary and preferably, non-caffeinated drinks.
  • Be aware that dehydration can occur quickly in cold temperatures too, especially in areas with low humidity and high winds. Caffeine can exacerbate dehydration and make workers more prone to cold stress.

Treating Cold Stress

  • Call 911 immediately if the individual is unconscious. Check for a pulse and respiration and follow the 911 operator’s instructions until medical help arrives.
  • Bring workers exhibiting symptoms of cold stress to a warm, dry area.
  • Remove and replace wet clothing and footwear.
  • Do not rub frostbitten skin or place in warm water as this may cause more damage. Cover the area loosely to protect it and seek medical attention.
  • Wrap hypothermic persons in dry blankets and a tarp or vapor barrier such as plastic sheeting. Give them warm, sweet liquids to drink if they are conscious. Call 911 or seek professional medical advice for instructions.

Have a safe and productive winter season. For more information and a sample work/warm-up schedule, visit the OSHA website.