Hazard Analysis — Cold-related Injuries and Illnesses

Working in cold environments increases a worker’s chances of suffering a cold-related injury or illness. Cold-related health problems can range from mild frostbite or bruising to death from severe hypothermia or head injuries from falling.

• Frostbite is a cold-related injury that usually affects the body’s extremities and exposed skin. The freezing of underlying tissues and skin results in frostbite. A worker's hands, feet, nose, and ears face the greatest risk of injury. If severe, amputation may be the only form of treatment. Symptoms may include developing gray or white patches (blisters in severe cases) on reddened skin and feeling numb or hard in affected areas. Workers experiencing frostbite should seek medical attention immediately. If not available, begin first aid by relocating the worker to a warm location, removing wet any clothing, and gently warming the affected area. Soak the affected areas in warm (never hot) water or keep applying warm cloths to affected ears, nose or cheeks for 20 to 30 minutes. Warming is complete when the skin is soft and sensation returns. Apply dry, sterile dressings to the frostbitten areas. Put dressings between frostbitten fingers or toes to keep them separated. If the frostbite is extensive, give warm drinks to the person in order to replace lost fluids. Do not use direct dry heat (such as a radiator, campfire, heating pad, or hair dryer) or hot water and do not rub the skin. Once frostbitten skin has been warmed it must not be returned to the cold or further damage may occur. (Source: Medline Plus from NIH, Accessed 3-14-14, http://www.nlm.nih.gov/medlineplus/ency/article/000057.htm)

Grade IV Frostbite

• Hypothermia occurs when the body’s core temperature drops from its normal temperature of 98.6ºF to less than 95ºF. The body is losing heat at a faster rate than it can generate it. Hypothermia most frequently occurs at temperatures below 40ºF but can occur at warmer temperatures if wind and moisture are present. Symptoms of hypothermia may include shivering, pale skin, slow or slurred speech, loss of coordination, slowed or shallow breathing, and loss of consciousness. Hypothermia is a life threatening injury that must be treated with medical attention immediately.

In a 2010 article written by Princeton University’s Rick Curtis, the stages of hypothermia are broken down by core temperature in addition to the signs and symptoms observed during each stage.

Identifying situations that could require workers to perform tasks in cold weather conditions should be a key part of the site safety planning process.

To determine if workers are at risk of cold-related injuries and illnesses consider the following:

• What is the air temperature the workers will be exposed to?
  • Temperature should be measured and recorded at least every 4 hours when below 30.2°F.
• Will walking or working surfaces be covered in ice or snow?
• What is the wind speed in the work area?
  • Wind speed should be measured at least every 4 hours when working indoors with wind speeds greater than 5 mph.
  • Wind speed should be measured every 4 hours when working outdoors in temperatures below 30.2°F.
• Will workers use toxic substances or be exposed to vibration?
• Will workers use gasoline, alcohol, or other liquids that evaporate quickly?
• Will workers be exposed to direct sun or be working in an enclosed area?
• Will workers be submerged in water or face the possibility of their clothing becoming wet?
• Is a place to warm-up readily available?
• Will warm sweet liquids be readily available?
• Do workers have health conditions or take medications that reduce their ability to regulate body temperature?
• Are workers medically certified to work in cold environments?
• Does the equipment used by the workers contribute to their cold stress?
• Will workers be contacting cold surfaces such as metal?
• Does the required personal protective equipment have the potential to raise a worker’s body temperature?
• Will the required work rate cause workers to sweat heavily resulting in wet clothing?
• Can equipment or scheduling be used to reduce the work that must be performed in cold environments?

When evaluating the severity of conditions, employers and workers should consider wind chill in addition to air temperature. The American Conference of Government Industrial Hygienists (ACGIH) chart on equivalent chill temperature provides a more accurate representation of the how cold an environment will actually feel due to wind. In addition, heat loss can be significantly increased if moisture is present.