Safety in a Power Outage

Food Safety

If the power is out for less than two hours, food in your refrigerator and freezer will be safe to eat. While the power is out, keep the refrigerator and freezer doors closed as much as possible to keep food cold longer.

If the power is out for longer than two hours, follow the guidelines below:

  • For the freezer section: A freezer that is half full will hold food safely for up to 24 hours. A full freezer will hold food safely for 48 hours. Do not open the freezer door if you don’t have to.
  • For the refrigerated section: Pack milk, other dairy products, meat, fish, eggs, gravy and spoilable leftovers into a cooler surrounded by ice. Inexpensive Styrofoam coolers are fine for this purpose.
  • Use a digital quick-response thermometer to check the temperature of your food right before you cook or eat it. Throw away any food that has a temperature of higher than 45 degrees Fahrenheit.

For guidelines on refreezing food when the power comes back on, visit the Food Safety and Inspection Services’ page on Food Safety in an Emergency:

The following resources provide additional information on preparing for emergencies and determining if your food is safe after a power outage:

Safe Drinking Water

When power goes out, water purification systems may not be working. Safe water for drinking, cooking and personal hygiene includes bottled, boiled or treated water. Your local health department can make specific recommendations for boiling or treating water in your area. Here are some general rules concerning water for drinking, cooking and personal hygiene:

  • Do not use contaminated water to wash dishes, brush your teeth, wash or prepare food, wash your hands, make ice or make baby formula. If possible, use baby formula that does not need to have water added. You can use an alcohol-based hand sanitizer to wash your hands.
  • If you use bottled water, be sure it came from a safe source. If you do not know that the water came from a safe source, you should boil or treat it before you use it. Use only bottled, boiled or treated water until your supply is tested and found safe.
  • Boiling water, when practical, is the preferred way to kill harmful bacteria and parasites. Bringing water to a rolling boil for one minute will kill most organisms.
  • When boiling water is not practical, you can treat water with chlorine tablets, iodine tablets or unscented household chlorine bleach (5.25 percent sodium hypochlorite):
    • If you use chlorine tablets or iodine tablets, follow the directions that come with the tablets.
    • If you use household chlorine bleach, add 1/8 teaspoon (~0.75 mL) of bleach per gallon of water if the water is clear. For cloudy water, add ¼ teaspoon (~1.50 mL) of bleach per gallon. Mix the solution thoroughly and let it stand for about 30 minutes before using it. (Note: Treating water with chlorine tablets, iodine tablets or liquid bleach will not kill parasitic organisms.)

Use a bleach solution to rinse water containers before reusing them. Use water storage tanks and other types of containers with caution. For example, fire truck storage tanks and previously used cans or bottles may be contaminated with microbes or chemicals.

Extreme Heat and Cold


Be aware of yours and others’ risk for heat stroke, heat exhaustion, heat cramps and fainting. To avoid heat stress, you should:

  • Drink a glass of fluid every 15 to 20 minutes and at least one gallon each day.
  • Avoid alcohol and caffeine. They both dehydrate the body.
  • Wear light-colored, loose-fitting clothing.
  • When indoors without air conditioning, use fans and open windows if outdoor air quality allows.
  • Take frequent cold showers and baths.
  • If you feel dizzy, weak or overheated, go to a cool place. Sit or lie down, drink water and wash your face with cold water. If you don’t feel better soon, get medical help quickly.
  • Work during cooler hours of the day when possible, or distribute the workload evenly throughout the day.

Heat stroke is the most serious heat illness. It happens when the body can’t control its own temperature and it rises fast. Sweating fails and the body cannot cool down. Body temperatures may rise to 106 degrees Fahrenheit or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency care is not given.

Warning signs of heat stroke vary but can include:

  • Red, hot and dry skin (no sweating).
  • Rapid, strong pulse.
  • Throbbing headache.
  • Dizziness, nausea, confusion or unconsciousness.
  • An extremely high body temperature (above 103 degrees Fahreheit).

If you suspect someone has heat stroke, follow these instructions:

  • Immediately call for medical attention.
  • Get the person to a cooler area.
  • Cool the person rapidly by immersing him/her in cool water or a cool shower, or by spraying or sponging him/her with cool water. If the humidity is low, wrap the person in a cool, wet sheet and fan him/her vigorously.
  • Monitor body temperature and continue cooling efforts until the body temperature drops to 101 or 102 degrees Fahrenheit.
  • Do not give the person alcohol to drink. Get medical assistance as soon as possible.
  • If emergency medical personnel do not arrive quickly, call the hospital emergency room for further instructions.

For more information on heat-related illnesses and treatment, see the CDC Extreme Heat Web site: Information for workers can be found on the National Institute for Occupational Safety and Health (NIOSH), Web site “Working in Hot Environments”:

These resources also provide information about extreme heat:


Hypothermia happens when a person’s core body temperature is lower than 35 degrees Celsius (95 degrees Fahrenheit). Hypothermia has three levels: acute, sub acute or chronic.

  • Acute hypothermia is caused by a rapid loss of body heat, usually from immersion in cold water.
  • Sub acute hypothermia often happens in cool outdoor weather (below 10 degrees Celsius or 50 degrees Fahrenheit) when wind chill, wet or too little clothing, fatigue and/or poor nutrition lower the body’s ability to cope with cold.
  • Chronic hypothermia happens from ongoing exposure to cold indoor temperatures (below 16 degrees Celsius or 60 degrees Fahrenheit). The poor, the elderly, people who have hypothyroidism, people who take sedative-hypnotics and drug and alcohol abusers are prone to chronic hypothermia, and they typically:
    • Misjudge cold.
    • Move slowly.
    • Have poor nutrition.
    • Wear too little clothing.
    • Have poor heating systems.

Causes of Hypothermia:

  • Cold temperatures.
  • Improper clothing, shelter or heating.
  • Wetness.
  • Fatigue or exhaustion.
  • Poor fluid intake (dehydration).
  • Poor food intake.
  • Alcohol intake.

Preventing Hypothermia:

  • Everyone, especially the elderly and ill, should have adequate food, clothing, shelter and sources of heat.
  • Electric blankets can help in poorly heated rooms.
  • Wear layers of clothing to keep in body heat.
  • Move around. Physical activity raises body temperature.

Water cooler than 75 degrees Fahrenheit (24 degrees Celsius) removes body heat more rapidly than can be replaced. The result is hypothermia. To avoid hypothermia:

  • Avoid swimming or wading in water if possible. If entering water is necessary:
    • Wear high rubber boots.
    • Ensure clothing and boots have adequate insulation.
    • Avoid working/playing alone.
    • Take frequent breaks out of the water.
    • Change into dry clothing when possible.

Helping someone who is Hypothermic

As the body temperature decreases, the person will be less awake and aware and may be confused and disoriented. Because of this, even a mildly hypothermic person might not think to help himself/herself.

  • Even someone who shows no signs of life should be brought quickly and carefully to a hospital or other medical facility.
  • Do not rub or massage the skin.
  • People who have severe hypothermia must be carefully re-warmed and their temperatures must be monitored.
    • Do not use direct heat or hot water to warm the person.
    • Give the person warm beverages to drink.
    • Do not give the person alcohol or cigarettes. Blood flow needs to be improved, and these slow blood flow.

For more information about hypothermia, see “Extreme Cold: A Prevention Guide to Promote Your Personal Health and Safety”:

Avoid Carbon Monoxide

For important information about the risk of carbon monoxide poisoning during a power outage, see “Carbon Monoxide Poisoning”: and “Questions and Answers About Carbon Monoxide Poisoning”: from CDC’s National Center for Environmental Health (NCEH).

Safety at Work During Power Recovery

As power returns after an outage, people at work may be at risk of electrical or traumatic injuries as power lines are reenergized and equipment is reactivated. CDC recommends that employers and employees be aware of those risks and take protective steps if they are in contact with or close to power lines, electrical components and the moving parts of heavy machinery. More information on electrical safety is available in “Worker Safety in Power Outages”:

Impact of Power Outage on Vaccine Storage

A power outage can have significant implications for vaccine storage. Information from CDC’s National Immunization Program should provide some guidance regarding vaccine storage issues:

Information adapted from the Centers for Disease Control and Prevention.