Our Top Cold Stress Questions
Get answers to the top questions about how to protect your employees against the dangers of cold stress when the temperature drops, including warm-up schedules and survival strategies.
Q: What is cold stress?
A: According to the National Institute for Occupational Safety and Health (NIOSH), what constitutes cold stress and its effects can vary across different areas of the country. In regions relatively unaccustomed to winter weather, near freezing temperatures are considered factors for cold stress. Whenever temperatures drop decidedly below normal and as wind speed increases, heat can more rapidly leave your body. These weather‐related conditions may lead to serious health problems such as frostbite or hypothermia. Anyone exposed to extreme cold or who works in cold environments may be at risk of cold stress.
Q: What’s the coldest temperature ever recorded?
A: Antarctica holds the record. There’s the official record, as recognized by the World Meteorological Organization (WMO), of –128.6°F recorded on July 21, 1983, and the unofficial record of –135.8°F recorded on July 31, 2010. The WMO record was measured with a thermometer, while the unofficial record was documented using satellite measurements. Closer to home, according to the National Oceanic and Atmospheric Administration (NOAA), the coldest temperature recorded in the U.S. was –80°F in Prospect Creek, Alaska on Jan. 23, 1971. In the contiguous U.S., Roger Pass, Montana holds the record at –70°F recorded on Jan. 20, 1954.
Q: Does the Occupational Safety and Health Administration (OSHA) have a regulation specific to protecting workers from extreme cold temperatures?
A: No. OSHA does not have a specific standard that covers working in cold environments but under the General Duty Clause, Section 5(a)(1) of the Occupational Safety and Health (OSH) Act of 1970, employers have a responsibility to protect workers from recognized hazards that are causing or likely to cause death or serious physical harm to their employees.
Q: Are employers responsible for paying for cold weather clothing for their employees?
A: No, with one exception. OSHA’s final rule for Employer Payment for Personal Protective Equipment became effective on Feb. 13, 2008 and the compliance deadline was May 15, 2008. OSHA Instruction / Compliance Directive CPL- 02‐01‐050 Enforcement Guidance for Personal Protective Equipment in General Industry became effective Feb. 10, 2011. It instructs OSHA enforcement personnel on both the agency’s interpretations of the standards and the procedures for enforcing them. The directive states “employers are not required to pay for ordinary clothing, skin creams, or other items used solely for protection from weather such as winter coats, jackets, gloves, and parkas that employees would normally have to protect themselves from the elements.” The guidance calls out the exception to this rule with the following enforcement: “NOTE: In the rare case that ordinary weather gear is not sufficient to protect the employee and special equipment or extraordinary clothing is needed to protect the employee from unusually severe weather conditions, the employer is required to pay for such protection. Clothing used in artificially controlled environments with extreme hot or cold temperatures, such as freezers, is not considered part of the weather gear exception.”
Q: More specifically, what are the employer’s responsibilities when it comes to protecting employees working in the cold?
A: The OSHA Winter Weather – Plan. Equip. Train. resource page offers the following guidance for employers who have employees working in cold environments. Employers should train workers. Training should include:
- How to recognize the environmental and workplace conditions that can lead to cold stress
- The symptoms of cold stress, how to prevent cold stress and what to do to help those who are affected
- How to select proper clothing for cold, wet and windy conditions
- Monitor workers physical condition
- Schedule frequent short breaks in warm dry areas to allow the body to warm up
- Schedule work during the warmest part of the day
- Use the buddy system (work in pairs)
- Provide warm, sweet beverages and avoid drinks with alcohol
- Provide engineering controls such as radiant heaters
Q: Does OSHA offer any guidelines regarding the type of clothing that should be used in cold environments?
A: In its Cold Stress Safety and Health Guide, OSHA offers the following guidance:
Dressing properly is extremely important to preventing cold stress. The type of fabric worn also makes a difference. Cotton loses its insulation value when it becomes wet. Wool, silk and most synthetics, on the other hand, retain their insulation even when wet. The following are recommendations for working in cold environments:
- Wear at least three layers of loose-fitting clothing. Layering provides better insulation. Do not wear tight-fitting clothing.
- 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.
- An outer wind and rain protection layer that allows some ventilation to prevent overheating.
- Wear a hat or hood to help keep your whole body warmer. Hats reduce the amount of body heat that escapes from your head.
- Use a knit mask to cover the face and mouth (if needed).
- Protect hands with insulated gloves (water resistant if necessary).
- Wear insulated and waterproof boots (or other footwear).
Q: What is wind chill?
A: Even relatively mild winds can greatly exacerbate the impact of cold temperatures. 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 35 mph, 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’s Wind Chill Chart (below) shows the impact winds of various speeds have on the real-world temperatures. If the temperature reading is 15°F with a 20 mph wind, the real-world feel is –2°F. The chart also indicates approximately when frostbite would set in based on the calculated wind chill temperatures.
Q: How cold is too cold to work outside?
A: There’s no exact answer to this question. Some jobs must be conducted regardless of how low the temperatures drop. Employers must use engineering (radiant heaters, wind screens, etc.) and administrative (job rotation, increased warming breaks, etc.) control measures to help limit worker exposure in extreme situations.
The American Conference of Governmental Industrial Hygienists (ACGIH) has developed a Work/Warm-Up Schedule for a four hour shift that takes both air temperature and wind speed into account. The schedule was adapted from the ACGIH 2012 Threshold Limit Values (TLVs). It provides recommendations on scheduling work breaks and ceasing non-emergency work. Here's an example schedule:
Q: What is hypothermia and what is the recommended treatment?
A: According to OSHA’s Cold Stress Safety and Health Guide, hypothermia occurs when body heat is lost faster than it can be replaced and 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 submersion in cold water.
Q: What are the symptoms of hypothermia?
- Mild symptoms:
- An exposed worker is alert.
- He/she may begin to shiver and stomp the feet in order to generate heat.
- Moderate to severe symptoms:
- As the body temperature continues to fall, symptoms will worsen and shivering stops.
- The worker may lose coordination and fumble with items in the hand, become confused and disoriented.
- He/she may be unable to walk or stand, pupils become dilated, pulse and breathing slow, and loss of consciousness can occur. A person could die if help is not received immediately.
Q: What can be done for a person 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 a vapor barrier (e.g., tarp, garbage bag). Do not cover the face.
- If medical help is more than 30 minutes away:
- Give warm sweetened drinks if alert (no alcohol) 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 a person is not breathing or has no pulse, OSHA recommends you:
- Call 911 for emergency medical assistance immediately.
- Treat the worker as per instructions for hypothermia, but be very careful and do not try to give an unconscious person fluids.
- Check him/her for signs of breathing and 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 three minutes.
- Recheck for breathing and pulse. Check 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. (NOTE: Chest compressions are recommended by the American Heart Association only if the patient will not receive medical care within three hours.)
- Reassess the patient’s physical status periodically.
Q: What is frostbite and what is the recommended treatment?
A: According to OSHA’s Cold Stress Safety and Health Guide, frostbite is an injury to the body that is caused by freezing of the skin and underlying tissues. The lower the temperature, the more quickly frostbite will occur. Frostbite typically affects the extremities, particularly the feet and hands. Amputation may be required in severe cases.
Q: What are the symptoms of frostbite?
- Reddened skin develops gray/white patches
- Numbness in the affected part
- Feels firm or hard
- Blisters may occur in the affected part in severe cases
Q: What can be done for a person suffering from frostbite?
- Follow the recommendations described above for hypothermia.
- Do not rub the affected area to warm it; this action can cause more damage.
- Do not apply snow/water.
- Do not break blisters.
- Loosely cover and protect the area from contact.
- Do not try to rewarm the frostbitten area before getting medical help; for example, do not place in warm water. If a frostbitten area is rewarmed and gets frozen again, more tissue damage will occur. It is safer for the frostbitten area to be rewarmed by medical professionals.
- Give warm sweetened drinks if the person is alert. Avoid alcohol.
Q: Why is cold water immersion particularly deadly?
A: According to the NIOSH Cold Stress Resource Page, cold water immersion creates a specific condition known as immersion hypothermia. It develops much more quickly than standard hypothermia because water conducts heat away from the body 25 times faster than air. While people in temperate climates typically don’t consider themselves at risk from hypothermia in the water, hypothermia can occur in any water temperature below 70°F. Survival times can be lengthened by wearing proper clothing (wool, silk and synthetics; not cotton); using a personal flotation device (PFD), life vest, immersion suit, or dry suit; having a means of both signaling rescuers (strobe lights, personal locator beacon, whistles or flares); and having a means of being retrieved from the water.
Q: What about traveling in extreme cold conditions?
A: The Centers for Disease Control and Prevention (CDC) Winter Weather Resource Page offers some suggestions regarding preparing a vehicle for winter travel. In addition to performing all of the vehicle manufacturer’s recommended maintenance, the CDC suggests that each fall vehicle owners do the following:
- Have the radiator system serviced or check the antifreeze level yourself with an antifreeze tester and add antifreeze as needed.
- Replace windshield wiper fluid with a wintertime mixture.
- Replace any worn tires. Make sure the tires have adequate tread and check their air pressure.
During the winter months, keep the gas tank near full to help avoid ice in the tank and fuel lines.
Q: What should I do if I become stranded in my vehicle during a winter storm?
A: The CDC suggests the following items be part of a winter survival kit for a vehicle:
- First aid kit
- A can and waterproof matches (to melt snow for water)
- Windshield scraper
- Booster cables
- Road maps
- Mobile phone
- Tool kit
- Paper towels
- Bag of sand or cat litter (to pour on ice or snow for added traction)
- Tow rope
- Tire chains (in areas with heavy snow)
- Collapsible shovel
- Container of water and high-calorie canned or dried foods and a can opener
- Flashlight and extra batteries
- Canned compressed air with sealant (for emergency tire repair)
- Brightly colored cloth
Should you find yourself stranded, the CDC advises you do the following:
- Tie a brightly colored cloth to the antenna as a signal to rescuers and raise the hood of the car (if it is not snowing).
- Move anything you need from the trunk into the passenger area.
- Stay awake; you will be less vulnerable to cold‐related health problems.
- Wrap your entire body, including your head, in extra clothing, blankets or newspapers.
- Run the motor (and heater) for about 10 minutes per hour, opening one window slightly to let in air. Make sure that snow is not blocking the exhaust pipe to help reduce the risk of carbon monoxide poisoning.
- As you sit, keep moving your arms and legs to improve your circulation and stay warmer.
- Do not eat snow because it will lower your body temperature.
- Huddle with other people for warmth.