Rob Coppola Senior Account Executive – Construction Insurance Practice Group View Bio

Anyone working in a cold environment may be at risk of cold stress. This includes workers required to work outdoors in cold environments, and also indoor workers who spend the majority of their work shift in cold rooms
without health and safety guidelines specific to these moderately cold temperatures.

A cold environment drives down the skin temperature, and eventually, the internal body temperature. As a result, the body is forced to work harder to maintain its normal temperature. Whenever temperatures drop below normal and wind speed increases, heat leaves the body more rapidly, and the body’s ability to warm itself decreases. When the body is unable to warm itself, cold stress occurs. This can lead to serious cold-related illnesses and injuries, permanent tissue damage, and even death.

Risk Factors That Contribute to Cold Stress

Some of the risk factors that contribute to cold stress are:

  • Wetness, dampness, dressing improperly, and exhaustion.
  • Predisposing health conditions such as hypertension, hypothyroidism, and diabetes.
  • Poor physical conditioning.

Injuries Due to Cold Stress

Employees who work in cold temperatures are subject to illnesses or injuries induced by cold. The most common types are: frostbite, hypothermia, and trench foot.

Frostbite
In a cold environment, to keep its internal temperature warm, the body will begin to shift blood flow from the extremities (hands, feet, arms, and legs) and outer skin, to the core (chest and abdomen). This shift allows the exposed skin and the extremities to cool rapidly. In many instances, rapid cooling results in freezing of the skin and tissues, which is known as frostbite.

Frostbite can cause permanent damage to the extremities, and in severe cases can lead to amputation. The risk of frostbite is increased in people with reduced blood circulation, and among people who are not dressed properly for extremely cold temperatures. Symptoms of frostbite include:

  • Reddened skin which develops gray or white patches in the fingers, toes, nose, or ear lobe.
  • Numbness, firmness, or hardness in the affected part.
  • Tingling, aching, loss of feeling, and blisters in the affected areas.

Frostbite Treatment
If a person is suffering from frostbite, loosely cover and protect the area from contact. Also, give warm sweetened drinks to the person if he or she is alert. However, those providing aid should never:

  • Rub the affected area to warm it
  • Apply snow or water to the affected area
  • Break blisters
  • Try to rewarm the frostbitten area before getting medical help
  • Serve alcohol to the affected person

Hypothermia

Prolonged exposure to cold temperatures causes the body to lose heat faster than it can be produced. The result is hypothermia, which occurs when the normal body temperature (98.6 °F) drops to less than 95 °F. Hypothermia is most likely at very cold temperatures, but it can occur even at cool temperatures (above 40 °F), if a person becomes chilled from rain, sweat, or immersion in cold water.

Symptoms of hypothermia include shivering, loss of coordination, confusion, disorientation, dilated pupils, loss of consciousness, and slowed heart rate, pulse, or breathing. A person exhibiting these symptoms could die if help is not received immediately.

Hypothermia Treatment
The following measures should be taken to assist an employee who is suffering from hypothermia:

  • Call 911 immediately in an emergency; otherwise seek medical assistance as soon as possible.
  • Move the person to a warm, dry area.
  • Remove wet clothes and replace with dry clothes, cover the body (including the head and neck) with layers of blankets; and with a vapor barrier (such as a tarp or garbage bag). Do not cover the face.

If medical help is more than 30 minutes away:

  • Give warm, sweetened drinks (no alcohol) if the person is alert, to help increase the body temperature. Never try to give a drink to an unconscious person.
  • Place warm bottles or hot packs in armpits, sides of chest, and groin. Call 911 for additional rewarming instructions.

If the person appears to not be breathing, or to not have a pulse:

  • Call 911 for emergency medical assistance immediately.
  • Check for signs of breathing and for a pulse. Check for 60 seconds.
  • If after 60 seconds the affected worker is not breathing and does not have a pulse, trained workers may start rescue breaths for 3 minutes.
  • Recheck for breathing and pulse for 60 seconds.
  • If the worker is still not breathing and has no pulse, continue rescue breathing.
  • Only start chest compressions per the direction of the 911 operator or emergency medical services.

Trench Foot

Trench foot is caused by prolonged exposure to wet and cold temperatures. Trench foot can occur at temperatures as high as 60 °F if the feet are constantly wet. In such circumstances, injury occurs because wet feet lose heat 25 times faster than dry feet. To prevent such heat loss, the body constricts the blood vessels to shut down circulation in the feet. This deprives the feet of oxygen and nutrients, and causes a buildup of toxic products, resulting in the death of skin tissue.

Symptoms of trench foot include:

  • Redness of the skin
  • Swelling
  • Numbness
  • Blisters

The following measures can be taken to assist an employee suffering from trench foot:

  • Call 911 immediately in an emergency; otherwise seek medical assistance as soon as possible.
  • Remove shoes, boots, and wet socks.
  • Dry the feet.

Determining Unsafe Temperature Using Wind Chill

Outdoor workers exposed to cold and windy conditions are at risk of cold stress. Wind chill is the term used to describe the rate of heat loss from the human body resulting from the combined effect of low air temperature and wind speed. The wind chill temperature is a single value that takes both air temperature and wind speed into account. For example, when the air temperature is 40°F, and the wind speed is 35mph, the wind chill temperature is 28°F—this measurement is the actual effect of the environmental cold on the exposed skin.

The National Weather Service offers a wind chill calculator an employer can use to calculate the wind chill temperature.

Preventing Cold Stress

Although OSHA does not have a specific standard that covers working in cold environments, employers have a responsibility to provide workers with a place of employment which is free of recognized hazards (including cold stress) that can cause death or serious physical harm to them.

Here are 10 tips employers can use to help prevent employees who work in cold temperatures from developing cold stress:

  1. Train workers on how to prevent and recognize cold stress illnesses and injuries and how to apply first aid treatment.
  2. Monitor workers’ physical conditions.
  3. Schedule frequent short breaks in warm dry areas, to allow the body to warm up.
  4. Schedule heavier work during the warmest part of the day.
  5. Provide plenty of warm, sweetened liquids to workers, but avoid alcoholic drinks.
  6. Assign workers to tasks in pairs so that they can monitor each other for signs of cold stress.
  7. Acclimatize new workers and those returning after time away from work by gradually increasing their workload, and allowing more frequent breaks in warm areas, as they build up a tolerance for working in the cold environment.
  8. Provide engineering controls such as radiant heaters.
  9. If possible, shield work areas from drafts or wind to reduce chill.
  10. Allow workers to interrupt their work if they are extremely uncomfortable.

The following safety tips can be used by employees to guard against cold stress:

  1. Wear at least three layers of loose fitting clothing. Layers should include an inner layer of wool, silk, or synthetic to keep moisture away from the body; a middle layer of wool or synthetic to provide insulation even when wet; and an outer wind and rain protection layer that allows some ventilation to prevent overheating.
  2. Wear a hat or hood to help keep your whole body warmer.
  3. Use a knit mask to cover the face and mouth (if needed).
  4. Use insulated gloves to protect the hands (water resistant if necessary).
  5. Wear insulated and waterproof boots (or other footwear).
  6. Monitor your physical condition and that of your coworkers.
  7. Stay dry, as moisture or dampness (e.g., from sweating) can increase the rate of heat loss from the body.
  8. Keep extra clothing (including underwear) handy in case you get wet and need to change.
  9. Drink warm sweetened fluids, but no alcohol.

Additional Information

OSHA Safety and Health Cold Stress Guide
Cold Stress (NIOSH)