Heat Stress/Cold Stress

Extreme heat or cold conditions may occur during emergency situations and be exacerbated by loss of heating and cooling during power outages. People also tend to work harder than usual when responding to an emergency, so the body may not be acclimated to a heavy workload under temperature extremes.    

Some tips for working under hot conditions include: 

  • Keep hydrated. Frequently drink small amounts of water, even before you get thirsty. Avoid alcohol, caffeine, and drinks with high sugar content.

  • Eat light, non-greasy meals.

  • Wear light-weight, light-colored, loose-fitting clothing.

  • Schedule heavy tasks earlier in the day or at a time during the day when the heat index is lower.

  • Take frequent rest breaks in a shaded or cool area.

  • Recognize heat stress signs and symptoms:
    • Heat exhaustion - heavy sweating; cool, moist skin; fast, weak pulse with fast shallow breathing; paleness; faintness; cramping; tiredness; headache; dizziness; nausea; or vomiting

    • Heat stroke - no sweating; red, hot, dry skin; rapid, strong pulse; dizziness; nausea; headache; confusion; uncontrolled twitching; or unconsciousness

    • Heat cramps - usually occur in the abdomen, arms, or legs

    • Heat rash - painful, red cluster of pimples or small blisters most likely on neck, upper chest, in groin area, under breast, or at the elbow or knee creases

  • Heat exhaustion and heat stroke are emergencies that can lead to death. Call for emergency assistance (e.g. 911). Then, gently move the victim to a cool and/or shady area. Loosen clothing, remove footwear, and elevate legs. Cool the victim by using cool water or cold packs; in low humidity, wet cloths can be used. 

Additional guidance related to working in hot conditions may be found as follows: 

  • Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health
    Heat Stress  

Technical guidance for the industrial hygienist includes: 

Some tips for working under cold conditions include:

  • Even 60 degrees Fahrenheit can be “cold” when a person is also wet.

  • Wear a warm head, face and ear covering and layered clothing:
    • 1st layer - material that allows the skin to breathe by allowing sweat to escape such as polypropylene or knitted silk.

    • 2nd layer - material that absorbs perspiration, but does not allow heat to escape such as polypropylene fleece or other synthetic fibers.

    • 3rd layer - material that traps body heat and keeps water or dampness out such as quilted coats filled with down or a lightweight microfiber and have a waterproof outer layer. If the coat is not waterproof, wear a water-resistant shell or windbreaker. The outer layer should include provisions for ventilation to prevent inner layers from becoming wet from sweat. For higher wind speeds and lower temperatures in the work area, higher insulation values of protective clothing are required. 
  •  Wear waterproof boots to protect feet. If boots have liners, replace them when damp.

  • Wear gloves or preferably mittens to protect hands. Replace when damp.

  • When working outside in a snow and/or ice-covered terrain, wear special safety glasses with side shields or goggles to protect against UV light, glare, and blowing ice crystals.

  • Drink plenty of non-alcoholic fluids to prevent dehydration and exhaustion. Heated drinks are helpful, but limit intake of caffeine. 

  • Take regular breaks to get out of the cold environment. Note: When taking a break, remove at least the outer layer of clothing and loosen remaining layers to permit sweat to evaporate. If clothing is wet, change into dry clothes before returning to a cold environment.

  • Recognize hypothermia’s warning signs:  
    • In adults – shivering, exhaustion, confusion, fumbling hands, memory loss, slurred speech and drowsiness 

    • In infants – bright red, cold skin; very low energy  

Hypothermia is an emergency that can lead to death. If a person has the above symptoms and his or her temperature is below 95 degrees Fahrenheit, call for emergency assistance.  Gently move the victim to a warm area and begin warming him or her.   

Additional guidance related to working in cold conditions may be found as follows:  

  • Centers for Disease Control and Prevention National Institute for Occupational Safety and Health

Technical guidance for the industrial hygienist includes: