It's something that may not cross your mind very often, but the concept of "cold" is relative. Ask anyone in the United States which state is the coldest, and most will respond, "Alaska." Yet, when asked how to work safely in cold weather, a safety manager in Anchorage responded, "I'm not sure. It's not all that cold here. You want to talk cold, talk to someone in Fairbanks." (Fairbanks is 250 miles north.)
We then talked with Duncan Jakes, an operations engineer with Fairbanks Natural Gas, who responded, "Temperatures get to about 55 below zero here in the winter, but we don't have any wind, so if you want to talk about cold weather, call someone in Prudoe Bay on the North Slope. They get a lot of wind with their cold." (This is on the north shore of Alaska, 350 miles north of Fairbanks.) We didn't go that far, but we did talk with two managers in Fairbanks and one in Dutch Harbor, which is on the Aleutian Islands in the Bering Sea.
Danger
"Cold" tends not to be a sexy subject. Relatively few deaths are related to the cold. In fact, the Bureau of Labor Statistics reports only four or five work-related fatalities a year due to cold weather. In addition, there are only about 250 lost workdays a year directly due to cold weather.
Yet, these numbers are deceptive, in that they do not take into account accidents due to hypothermia-triggered disorientation. They also fail to take into account the number of workdays lost due to cold-related illnesses, such as colds and flus.
When it comes to cold weather, there are four major concerns, which can be grouped into two categories:
"Dry cold" includes thermometer temperatures as well as cold winds, which combine to create the well-known "wind chill factor." During cold weather, approximately 60 percent of a person's body energy is used to heat the body. When exposed to frigid temperatures, the body's temperature decreases, causing blood vessels to constrict, decreasing the blood flow to the skin. The exposure of the skin to the cold can lead to frostbite and possibly even hypothermia.
"Wet cold" includes dampness in the air, as well as direct contact with water, such as falling into a creek or lake, or being exposed to sleet or freezing rain. While the body naturally loses heat in dry, cold weather, it loses even more when exposed to wet cold. In fact, according to OSHA, wet clothing causes the body to lose heat 24 times faster than dry clothing.
Cold weather is even more of a problem for people ingesting certain substances (primarily alcohol, caffeine, nicotine or some prescription drugs), as well as for those with certain diseases, such as diabetes, heart disease or thyroid conditions.
The three most common and serious problems associated with the cold are frostbite, hypothermia and trenchfoot.
Frostbite. As noted earlier, blood vessels near the skin constrict in cold weather so the body can conserve blood to keep vital internal organs warm. Eventually, the skin begins to freeze, causing ice crystals to form between cells and draw water from them. This leads to cellular hydration. The most common areas for frostbite are the fingers, toes, cheeks and nose.
Symptoms of frostbite include an uncomfortable sensation of coldness, then tingling, stinging or aching in the exposed area, followed by numbness. The area generally appears white and cold to the touch.
Hypothermia. Each year, more than 700 people in the United States die from hypothermia. When the body temperature falls below a certain level, normal muscular and cerebral functions are impaired. At 95 degrees, the person experiences shivering, an inability to engage in complex motor functions, lethargy and mind confusion. Between 95 and 90 degrees, the person experiences dazed consciousness, an inability to complete simple motor functions, slurred speech and sometimes irrational behavior. Below 90 degrees, blood flow, breathing and heart rate decrease to the point where the person may lose consciousness and the heart may stop.
Trenchfoot. This is primarily caused by long, continuous exposure to a wet, cold environment or immersion in cold water. It is common among commercial fishermen. Symptoms can include tingling or itching, burning, pain, swelling and sometimes blisters.
Solutions
There are five areas to address: torso protection, extremity protection, training, engineering controls and work practices.
Torso protection. The most important step in cold-weather protection is wearing the right clothing. The ideal combination is three layers:
- An outer layer to protect against the wind and allow ventilation. Gore-Tex or nylon are recommended. Gore-Tex allows perspiration to evaporate but prevents wind and water from penetrating.
- A middle layer of wool or synthetic fiber to absorb perspiration and retain insulation. Down is a lightweight insulator, but it is ineffective if it becomes wet. What is preferable - wool or synthetic? Wool offers two benefits. It is a good insulator, and it is less flammable than synthetics, turning to ash and falling away from the body, which may be important for electric utility crews. Because it is so heavy, however, it can hamper movement, and it becomes very heavy when wet. Synthetic fabrics are lightweight and provide better insulation if they become wet, but they are more flammable and adhere to the body if they catch fire.
- An inner layer, such as thermal underwear, to allow ventilation. Cotton or synthetic weave are recommended.
Extremity protection. It is important to pay special attention to coverings for the feet (insulated footgear to protect against the cold and dampness), hands and head. Up to 40 percent of the body's heat can be lost when the head is exposed due to the amount of blood that must circulate to the brain. "In addition to warm jackets and bibs, we recommend good boots, jackets with a hood and gloves for our employees," said Fairbanks Natural Gas' Jakes. What about facemasks? "Employees don't often wear these, because they can get frosted up, and it can be difficult to breathe," he replied. "In most cases, warm breath is sufficient to keep their faces warm anyway."
Dutch Harbor-based UniSea, a fishing enterprise in the Aleutian Islands, takes employee safety very seriously, not only for humanitarian reasons, but because the closest medical facility is in Anchorage, 800 miles away by air. "Most of the weather we experience here is cold and wet," said Gregg Bishop, safety manager. "We also have a phenomenal amount of wind, so wind chill is a problem."
The company provides its employees with specialty rain gear, including a water-resistant, nylon-coated deck suit, insulated rubber boots with optional liners (which most employees use, although some prefer multiple pairs of socks), rubber gloves with cotton liners and hats.
All managers interviewed emphasized the importance of having a dry change of clothing available in the event the first set becomes wet or otherwise unwearable.
Training. "Even people who work in cold weather most of the year can have a tendency to become complacent," explained David Jacoby, public works director for the City of Fairbanks. "As such, we have a training program that emphasizes awareness and constant reminders." During some portions of the year, this training takes place monthly. In colder months, it takes place every two weeks. In the coldest months, it takes place weekly. "We are constantly reminding employees of the importance of staying warm, and we even provide them with a 'Stay Safe in the Cold' checklist," he adds.
The most common problem employees experienced in the past was frostbite. "On occasion, they would step out of warm vehicles with no hats and no gloves, then end up grabbing a piece of steel with a bare hand and freezing the hand," Jacoby said. "Since we have instituted the frequent-reminder training program, though, we have not had any frostbite incidents."
UniSea also emphasizes cold-weather safety in its training. "During our orientation, for example, we tell employees that if their feet feel even a bit damp due to perspiration, they should change their socks and boot liners," Bishop said. "If they can stay dry, they will do fine. Once they get wet, though, it can take a long time to recover."
Engineering controls. These can include the use of on-site heat sources (such as radiant heaters or contact warm plates), shielding from windy conditions (such as work tents), heated shelters where employees can retreat to warm up on occasion and thermal insulating materials on equipment handles.
Work practices. There are five recommendations:
1. Allow a period of adjustment to the cold before asking employees to work full schedules in the cold. "When employees come back from visiting their homes on vacation, we expose them to the elements a bit at a time," Bishop said. Many of the company's employees are from the Philippines, Vietnam, Ethiopia, Mexico, Somalia and other warm-weather countries.
2. Require the buddy system so employees can aid co-workers if they begin experiencing problems.
3. Select the warmest hours of the day to work in the cold, if possible (e.g., midday, rather than early mornings and late afternoons). "We try not to do much outdoor work at all in the winter," Jakes said. "We limit it mostly to meter reading, and we do no cold-weather construction."
4. Allow employees to set their own work paces and take breaks as necessary to warm up. "Our cold-storage freezers operate at 20 degrees below zero, so we allow employees to operate on a 20- minute rotation system, wearing fully insulated freezer suits," Bishop said.
5. Ensure frequent hydration, with a special emphasis on warm, high-calorie drinks, and encourage employees to eat hot, high-calorie meals. "During the time we operate 24 hours a day, we offer breakfast, lunch, dinner and a midnight meal," Bishop said. The galley offers several entrees for each meal, most of which are high in carbohydrates and proteins to help employees maintain heat and energy. "During breaks, we offer cookies, tea, coffee and juices," he added. "As such, employees can eat or snack up to eight times a day."
Treatment for Frostbite and Hypothermia
Frostbite. Arrange for professional medical attention (e.g.: a call for an EMT crew or a direct drive to a hospital). In the meantime:
- Move the person to a warm, dry area.
- Remove any tight clothing that might restrict blood flow.
- Place the person in lukewarm (not warm or hot) water for 25 to 40 minutes to gradually warm the tissue.
- Cover the area with dry, sterile gauze or bandages.
- Do not massage the area, as it may cause greater injury.
Hypothermia. Seek professional medical attention immediately. In the meantime:
- Get the person to a warm, dry area.
- Remove wet clothing.
- Add layers of warm clothing, wrap the person in blankets and/or lay the person in a pre-warmed sleeping bag.
- Provide a warm, sweet-tasting beverage (no alcohol or caffeine).
- Move the person's arms and legs gently to restimulate circulation.
- Do not immerse the person in water of any temperature. Even warm water can cause a shock to the body that could stop the heart.
Water exposure. Remove wet clothes. Immerse the person in lukewarm water, unless suffering from hypothermia as discussed above. Provide warm, dry clothes. Seek medical attention if needed.
For trenchfoot, move the person to a warm, dry area. Treat the tissue carefully with washing and redrying. Rewarm the area, and provide slight elevation. Seek medical assistance. David Jacoby of the City of Fairbanks welcomes calls from readers interested in more information on cold-weather safety. His number is (907) 459-6770.
About the author: William Atkinson is a business writer with more than 25 years' experience. He specializes in writing on safety, health and environmental issues.