Working in the Cold: Stay Safe When Temperatures Drop
Originally published by: Safety & Health Magazine — November 22, 2020
The following article was produced and published by the source linked to above, who is solely responsible for its content. SBC Magazine is publishing this story to raise awareness of information publicly available online and does not verify the accuracy of the author’s claims. As a consequence, SBC cannot vouch for the validity of any facts, claims or opinions made in the article.
Editor’s Note: NFC’s FrameSAFE program includes a Toolbox Talk on preventing hypothermia and frostbite that provides a quick reminder of the primary symptoms of these conditions. Consider reviewing this information with your employees regularly. While OSHA does not have a specific standard for working in cold weather, employers are still required to identify hazards and provide a safe workplace. OSHA’s requirement to provide potable water to employees (see 1926.51(a)(1)) is also applicable in cold weather as the dry air affects hydration. (Learn more.)
Photo: Missouri Department of Transportation/flickr
Lost-time injuries and illnesses resulting from “environmental cold” spiked nearly 142% in 2018 – soaring to 290 cases from 120 the previous year, according to the Bureau of Labor Statistics.
Those cases, plus the 280 reported in 2019, are a likely indicator of a lack of employer and worker understanding about the dangers of cold stress.
- The American Conference of Governmental Industrial Hygienists has developed thresholds, using air temperature and wind, for employers and workers to understand the levels of cold stress danger. Also, OSHA has posted ACGIH’s work/warm-up table for four-hour shifts on its winter weather website.
- A waterproof outer layer of clothing or personal protective equipment and waterproof footwear can help combat another issue of working in cold environments: moisture. Like wind, moisture can displace heat from workers’ bodies.
- Hypothermia, frostbite, trench foot and chilblains are the major types of conditions resulting from cold stress.
What are the dangers?
Along with air temperature, wind and moisture can create issues for employees working in the cold. Water, including sweat, can displace body heat 25 times faster than dry air, according to the Canadian Center for Occupational Health and Safety.
Likewise, wind can blow away the body’s protective external layer of heat. This is why wind chill is an important factor to understand. So, for example, when the temperature is 25° F and the wind is blowing 25 mph, the wind chill is 9° F, resulting in more dangerous conditions.
The American Conference of Governmental Industrial Hygienists used air temperature and wind speed to develop three thresholds of cold stress hazards:
Little danger: Freezing of exposed skin within one hour
Danger: Freezing of exposed skin within one minute
Extreme danger: Freezing of exposed skin within 30 seconds
With no wind, the temperature can drop to -20° F and still pose little danger to workers. But if the wind speed reaches 20 mph or more, then the danger threshold moves up to 10° F.
ACGIH also developed a work/warm-up schedule for four-hour shifts (available on OSHA’s website at osha.gov/dts/weather/winter_weather). On this sliding scale, no noticeable wind and an air temperature between -25° and -29° F translates to a maximum work period of 75 minutes. However, if the wind reaches 20 mph or more and the temperature is between -15° and -19° F, the maximum work period is 40 minutes. At -25° F or colder and with a wind speed at the same 20 mph or greater, ACGIH recommends that all non-emergency work stop.
Martin Tirado, CEO of the Snow and Ice Management Association, said a good rule of thumb is a 15-minute break for every hour of work. When the temperature dips below zero, workers should have shorter work periods with a break that’s equal in length (i.e., work for five minutes and warm up for five minutes).
What to know
OSHA doesn’t have a standard that covers work in cold environments, but it can enforce its General Duty Clause, which requires employers to provide a workplace “free from recognized hazards.”
OSHA and NIOSH say employers should educate workers about conditions that can cause cold stress, as well as the symptoms of related ailments, including frostbite and trench foot and how to prevent them.
OSHA also advises instructing employees on how to dress appropriately for cold conditions, in addition to monitoring them and providing a place to warm up with hot beverages. Whenever possible, schedule work for the warmest part of the day and use a buddy system to help workers monitor each other.
Another option: the use of radiant heaters or other engineering controls to protect against cold stress. First aid kits should include a thermometer and chemical hot packs.
Workers should have extra gloves, hats, socks, jackets and blankets accessible, and a thermos or container with something hot to drink. They also should avoid touching any metal with bare skin.
What to wear
Many of the recommendations to help prevent cold stress involve clothing and personal protective equipment. Experts say layering clothing provides better insulation. NIOSH health scientist Brenda Jacklitsch said this allows workers to remove layers if they become too warm or if their clothing gets wet.
A waterproof outer layer is important when working in a wet, cool environment, OSHA says, and this layer should provide ventilation to prevent overheating. For middle layers, the agency suggests wool or synthetic material “to provide insulation even when wet,” while an inner layer of wool, silk or a synthetic material such as polypropylene is ideal to keep moisture – including sweat – away from the body.
Body heat tends to escape from the head and other extremities, such as the ears, feet and hands, so it’s important to keep them covered, Jacklitsch says.
Make sure clothing isn’t too tight, because tight-fitting clothing can impede circulation and the body’s source of heat. Boots and footwear should be insulated and waterproof.
CCOHS advises finding the right thickness for socks: If socks are too thick, they can lose their insulating properties if compressed inside footwear and will make that footwear tight, possibly slowing blood flow to the feet and toes.
Conversely, if socks are too thin, workers are at risk of developing blisters.
From the "First Aid" course offered by the National Safety Council. Learn more about NSC first aid and CPR training – including online and classroom training for learners, and courses and materials for instructors
What to watch
Hypothermia is one of the greatest dangers facing people who work in the cold. This medical emergency occurs when the body temperature drops below 95° F.
According to OSHA, an important milder symptom of hypothermia is uncontrollable shivering, which indicates the body is losing heat and trying to rewarm itself.
Other symptoms include fatigue, confusion, loss of coordination and slurred speech. People in the late stages of hypothermia may stop shivering or lose consciousness, or have blue skin, dilated pupils, a slowed pulse and slower breathing.
In cases of hypothermia, call 911 immediately. Move the victim into a warm, dry area and remove wet clothing and replace it with dry garments. OSHA suggests wrapping the victim’s entire body – including the head and neck – in layers of blankets with an additional “vapor barrier” such as tarp or garbage bag. Don’t cover the victim’s face.
NIOSH says to first concentrate on warming the center of the victim’s body – the chest, neck, head and groin.
If assistance is more than 30 minutes away, OSHA recommends giving the victim warm sweetened drinks (but no alcohol) if he or she is conscious. You also can place warm bottles or hot packs on the sides of the chest, groin and armpits. Be prepared to give CPR if the victim isn’t breathing or has no pulse.
Other major types of cold stress:
Frostbite. This condition is the result of freezing skin and surrounding tissue. In severe cases, it can lead to amputation of body parts or severe damage to the body. Signs include white/gray patches on the fingers, toes, noses and earlobes. Skin also may look bluish, gray, pale or waxy.
Workers affected may complain of tingling, loss of feeling or aching, or have blisters. Anyone experiencing frostbite needs to be taken to a warm place as quickly as possible and medical personnel should be alerted. If the feet or toes are affected, don’t let the victim walk because it could cause more damage, NIOSH says.
More first aid tips for frostbite:
- Once indoors, remove any clothing or accessories that might hinder circulation.
- Immerse the affected area in warm – not hot – water (temperature should be comfortable to the touch, especially for unaffected areas of the body).
- Use a loose, dry cloth to protect the frostbitten area until medical help arrives.
- Don’t rub the affected area – this could damage the skin.
- Don’t warm the frostbitten area with direct heat from items such as a lamp – this can cause burns.
- Don’t thaw the affected area if it has the potential to freeze again, because this can cause additional damage.
As with hypothermia, you can give someone experiencing frostbite warm, sweet nonalcoholic drinks.
Trench foot. Also known as immersion foot, trench foot can occur in temperatures as high as 60° F if a worker’s feet are “constantly” wet, NIOSH says. Warning signs include reddening skin, tingling, numbness, leg cramps and blistering. Among the steps to take if a worker is suffering from this condition: Remove shoes and wet socks; dry the feet; and instruct the person to avoid walking, which can further damage tissue.
Chilblains. Chilblains are the painful inflammation of small blood vessels in the skin that occur in response to repeated exposure to cold – not freezing – air, according to the Mayo Clinic. NIOSH adds that the condition can occur in temperatures as high as 60° F. Symptoms may include redness, itching and blisters. Victims should avoid scratching the skin, which should be slowly warmed.
Cold weather and COVID-19
If you’re working outside in the cold and wearing an item such as a ski mask or balaclava, is that enough protection against COVID-19? Possibly.
Items with multiple layers of fabric that cover the mouth and nose “would be similar to wearing a cloth mask,” NIOSH experts told Safety+Health. However, they noted that some ski masks, balaclavas or similar items can have openings around the mouth and nose, making them insufficient protection.
State and local regulations may vary on cloth facial mask requirements for outdoor workers, but the Centers for Disease Control and Prevention recommends the use of masks when in public and around people you don’t live with.
“While there are no additional risks associated with wearing a mask or N95 respirator in the cold, compared to not wearing one, if a worker feels that working in the cold is having a negative effect on the respiratory system, they should consult a health care provider about their individual health concerns,” the NIOSH experts said. “An occupational safety and health professional should work with the employee to determine the most appropriate cloth face covering or respirator for their specific workplace settings.”