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Cold Stress: Keeping Safe in California’s Winter Weather

Health & Safety Training, NES Safety Topic

Written by: Virginia McCormick, NES Inc.

Cold Stress: Keeping Safe in California's Winter Weather
While most Californians can expect milder winter weather than this, it is still important to recognize the dangers of cold stress.


Cold Stress and California’s Winter Weather

Many California residents are familiar with the health risks associated with our state’s hot summers. But even in California’s mostly Mediterranean climate, workers and employers must also be aware of cold stress as the middle of winter approaches.

Cold stress is typically used as a blanket term to cover the various injuries or health effects that come with working in cold conditions. While there are no specific guidelines for working in cold environments, employers have a responsibility to protect their workers from workplace hazards – including cold stress. According to OSHA, anyone exposed cold conditions may be at risk, including construction workers, farmers, and even those working with freezers.

Need to refresh your heat illness safety awareness? Check out the June 2017 NES blog post Heat Illness Prevention: Managing Rising Temperatures in the Workplace for more information.


OSHA QuickCards Cold Stress
OSHA QuickCards can be used as an easy reference for how to identify and manage common types of cold stress. The above QuickCards can be downloaded here.


Becoming familiar with common cold stress symptoms is one of the best ways to keep yourself and others safe. This knowledge, along with proper first aid training and protective equipment, will help anyone ease the stress of particularly cold California workdays.


Types, Symptoms, and Treatments of Cold Stress

According to the Centers for Disease Control and Prevention (CDC) website, the four most common cold stress-related hazards are hypothermia, frostbite, trench foot, and chilblains. If you notice any symptoms of cold stress in an individual, make sure to take the person’s temperature. If it is below 95°F, the situation is considered an emergency, and immediate medical attention is required.


Arguably one of the most dangerous and well-known results of cold stress is hypothermia. As defined by CDC, hypothermia can occur when the body loses heat faster than it can produce heat. The symptoms of hypothermia include:

  • Shivering
  • Exhaustion
  • Confusion or memory loss
  • Slurred speech, drowsiness, limited movement

Brain function is affected when body temperature is too low, which can make a person unable to think clearly or move well. This is what makes hypothermia especially dangerous, as the victim may not realize what is happening or may not be able to move quickly enough to do anything about it. If hypothermia is suspected, the first thing to do is to seek medical attention.

While waiting for medical attention, hypothermia treatment begins with slowly warming the victim. Gently move the victim into a warm area and remove any wet clothing. The center of the body – such as the chest, head, and neck – should be warmed first using layers of dry blankets or clothing. Trying to warm the victim’s feet or hands before the body’s center may cause shock. Warm, nonalcoholic and noncaffeinated beverages may also be provided to a conscious victim.

A person with severe hypothermia may be unconscious, or may appear to not be breathing or have a stopped pulse. In this case, continuous CPR administered by a qualified person is recommended while the victim is being slowly warmed, even if he/she appears unresponsive. Once the body temperature has increased, keep the victim warm and dry until medical attention arrives.


Frostbite is a bodily injury caused by the freezing of specific body parts, particularly smaller areas like fingers, ears, and toes. Those exposed to extreme cold can be susceptible to frostbite in a matter of minutes, according to the National Weather Service (NWS). The symptoms of frostbite include:

  • Skin discoloration – blue, white, or grayish-yellow patches
  • Cold, firm, or waxy skin
  • Numbness

Frostbite treatment mirrors much of the treatment for hypothermia. Victims should again be gently moved to a warm place. Frostbitten areas should be assessed and then soaked in warm water until the area feels warm to touch. CDC recommends not to use or rub frostbitten areas, as this can cause more damage. Frostbite victims, like hypothermia victims, should also be warmed slowly and should not be exposed to direct heat sources like heating pads, lamps, or stoves. Because the victim’s frostbitten areas are likely numb, he/she will not be able to feel burns.


Spotting Frostbite & Hypothermia
Knowing the symptoms of hypothermia and frostbite, as listed in this excerpt of a CDC infographic, can make cold stress easier to prevent. See the full infographic here.


Trench Foot

While not often thought of as an occupational hazard, trench foot is a common modern condition brought about by prolonged exposure of the feet to damp, cold, sometimes unsanitary environments. This form of cold stress is focused on the feet and can be very painful for the victim. Symptoms of trench foot include:

  • Itching or tingling sensations
  • Cold, blotchy, or flaky skin
  • Blisters and sores

When suffering from trench foot, victims are recommended to first clean, dry, and elevate their feet. Like frostbite, trench foot may be treated by submerging affected feet in warm water for a few minutes until warm. Once the temperature of the feet has increased, the victim should wear clean, dry socks daily. Medical attention is advised for severe cases, as untreated trench foot can lead to tissue death and possible amputation.


Chilblains are small skin sores that typically occur on hands or feet after exposure to cold temperatures. Sometimes known as pernio, symptoms of chilblains include:

  • Itching or burning sensations
  • Bumps or blistering
  • Discoloration – red or purple patches

These skin sores can be painful but are often self-treatable and rarely leave permanent damage. Victims are advised to keep affected areas warm and unrestricted and to use topical creams to relieve pain, itch, or burning sensations.

As always, we recommend anyone interested in learning more about cold stress hazards to seek the advice of a medical professional.


Preventing Cold Stress as an Employer

Preventing cold stress in the workplace starts first with the employer. By regularly checking weather and temperature reports, or by providing proper personal protective equipment (PPE) like gloves or cold-weather uniforms, an informed and prepared employer can better be equipped to prevent cold stress.


The wind chill chart, shown above, can be used to calculate the exposure limits using air temperature and wind speed. A wind chill calculator can also be found on the NWS website.


When exposed to outdoor weather, both air temperature and wind speed can drastically affect how cold a worker may feel. These factors together are referred to as wind chill. Using the NWS Wind Chill Calculator, employers can input current air temperature and wind speed to find out the wind chill temperature for their environment.

Employers should make sure their workers are properly hydrated when exposed to cold stress, as it is easy to become dehydrated in cold conditions. OSHA recommends in its Cold Stress Guide that employers implement a buddy system so that workers can monitor each other for signs of cold stress. Employers should also schedule heavy work during the warmer part of a day, give workers frequent breaks in warm areas, and help build up cold weather tolerance in new workers by gradually increasing their exposure to cold weather.


Preventing Cold Stress as an Employee

Just like employers, workers should also make sure they are up-to-date with current weather and temperature forecasts. Simply checking forecasts before the day will make a worker more likely to spot cold stress before an injury or illness occurs.

Workers should make sure to wear proper protective equipment while working in cold conditions. Insulation is critical to preserve body heat, and workers can achieve better insulation by layering clothes. Layering also allows a worker to add and remove layers to adjust for different needs during the workday. Gloves and hats help prevent frostbite, and properly insulated and waterproof shoes can protect against trench foot.

As with heat stress, the best way to treat cold stress is to learn how to recognize the symptoms and to act quickly when those symptoms start to appear. While employers are highly recommended – and often required – to provide first aid and emergency resuscitation training for their workers, employees may also seek training on their own. Training can help employers and workers feel more confident in their abilities to prevent cold stress, treat symptoms when they arise, and protect their health and the health of others around them.


Looking for Training?

Check out NES’ 8-hour Standard First Aid, CPR & AED course page for details about the relevant training we provide, from assessing emergency situations to administering basic first aid. If you have questions regarding temperature/weather-related illnesses and injuries at your workplace, please contact NES at 916-353-2360 / 800-637-2384 or via email at



OSHA: Winter Weather Cold Stress Article

Centers for Disease Control and Prevention: Cold Stress – Cold Related Illnesses



National Weather Service: Cold Weather Safety

Wind Chill Calculator

OSHA Cold Stress Guide