Winter has arrived, and it’s time to be mindful of the impact that cold stress can have on those who work outdoors for extended periods of time. For most people, just being outdoors for a few hours in the winter is more than enough time to become quite uncomfortable. For those who work in outdoor careers like construction or utilities, special care is needed when cool weather arrives.
Cold stress comes in three forms: trenchfoot, frostbite, and hypothermia. Each one has its own unique characteristics which we’ll explore below.
Trenchfoot is an injury of the foot that occurs when a worker’s feet are wet or submerged in water for extended periods. Trenchfoot is a non-freezing type of injury that can happen at temperatures as high as 60 degrees. Since wet skin loses heat at a rate of up to 25 times faster than dry skin, this type of cold stress can occur well above freezing temperatures. Symptoms of trenchfoot include a reddened skin, pair, swelling. or numbness.
This is likely the most well-known type of cold stress. Frostbite occurs when skin or other tissue freezes. Telltale signs of frostbite include discolored skin on extremities such as the nose, ears, or fingers. Tingling, aching, and a loss of feeling in the affected areas are also common symptoms.
Hypothermia occurs when the body’s internal temperature dips below 95 degrees. Typically hypothermia occurs when the temperature is below freezing, but not always. It can occur with temperatures as high as 40 degrees when workers are wet from rain or sweat. Uncontrolled shaking is one of the first signs of a mild case of hypothermia. More advanced symptoms include confusion, loss of coordination, and slowed breathing.
Being aware of the conditions your crews will be facing during the colder months can help you prepare them to work safely outdoors. Monitoring outdoor temperatures and precipitation types and amounts can help you ensure that you’re providing a work environment that emphasizes safety first. OSHA’s winter weather resource page provides additional resources including a helpful chart that lists safe outdoor working times in relation to the temperature.