Protecting Workers in Cold Environments
by Larry Casey
Labor Education Service
University of Minnesota

Prolonged exposure to freezing temperatures can result in health problems such as frostbite and hypothermia. Workers, especially those in construction, need to be especially mindful of the temperature and extreme weather conditions.

An individual gains body heat from food and muscular activity. Body heat is lost through convection, conduction, radiation and sweating to maintain a constant body temperature. When the body drops even a few degrees below its normal 98.6F (37C), the blood vessels constrict, decreasing blood flow to reduce heat loss from the surface of the skin. Shivering is a natural body response which generates heat by increasing the body's metabolic rate.

The four environmental conditions that cause cold related stress are low temperatures, high/cold winds, dampness and cold water. Wind chill and a combination of temperature and wind speed are crucial factors when working outside. The wind has no impact on the temperature of objects. Wind does affect the skin as it penetrates clothing.

Major Risk Factors For Cold Related Stresses

• Wearing inadequate or wet clothing increases the effects of the cold on the body.
• Taking certain drugs or medications such as alcohol, nicotine, caffeine and medication that inhibits the body's response to the cold or impairs judgment.
• Having a cold or certain diseases, such as diabetes, heart, vascular and thyroid problems may make a person more susceptible to winter elements.
• Men experience far greater death rates due to cold exposure than women. This is probably due to inherent risk-taking activities, body fat composition or other physiological differences.
• Becoming exhausted or immobilized may speed up the effects of cold weather.

Frostbite occurs when the skin actually freezes, causing ice crystals to form between cells and draw water from them. Although this typically occurs at temperatures below 30F, wind chill can cause frostbite at above freezing temperatures.

The effects of frostbite include uncomfortable sensations of coldness at first, followed by tingling, stinging or an aching feeling of the exposed area followed by numbness. Ears, fingers, toes, cheeks and noses are primarily affected. Frostbitten areas appear white and cold to the touch. The appearance of frostbite varies depending on whether rewarming has occurred.

If you suspect frostbite, you should seek medical assistance immediately. Frostbitten parts should be covered with dry, sterile gauze or soft, clean bandages. Do not massage frostbitten tissue because this sometimes causes greater injury. Severe cases may require hospitalization and even amputation of affected tissue or limb.

For further information about protecting workers in cold environments check the U.S. Department of Labor website at www.osha.gov.

Article submitted by Larry Casey, Labor Education Service, University of Minnesota, 612-624-7352 or e-mail Larry Casey