Persons entering areas and buildings after a tornadic event face various potential hazards, including but not limited to electrical hazards, structural hazards, displacement of wildlife, exposure to chemicals such as petroleum products or carbon monoxide, and mold growth from water-impacted building materials. First and foremost, life safety issues, such as ensuring the home or building is structurally sound and avoiding electrical shock or carbon monoxide poisoning, must be considered before any entry or clean-up is initiated.

Before You Begin - The Incident Command System (ICS)

When there is an incident, such as a natural or human-made disaster, an Incident Command System (ICS) is typically established for response command, control, and coordination. ICS is a nationally-recognized framework under which all involved or interested entities and stakeholders (whether federal, tribal, state, local, or private) operate. It establishes one command structure with known and scheduled deliverables and uses standardized terminology.

Because the ICS is mandated for disaster response agencies such as the Federal Emergency Management Agency (FEMA), U.S. Environmental Protection Agency (EPA), and U.S. Coast Guard (USCG), it is important to note that the ICS may be in place and active in your area, even if the response phase is over and the recovery phase has begun. It is often best to start by performing a search on an internet search browser for "ICS Liaison" and the name of the event or location to see if the ICS has a website set up. If this does not yield an established website for your response, go to and enter the affected property address.

If the area inclusive of the address entered has been declared for individual assistance, you can try "Find Assistance" and then "Apply Online" if applicable. If you do not have access to the internet, you may contact FEMA directly:

  • Call 7 a.m. to 11 p.m. ET, 7 days a week:
    • 1-800-621-FEMA (1-800-621-3362)
    • TTY 1-800-462-7585
    • 711 or VRS 1-800-621-3362
    • You can also email: [email protected] (get a response in 1 to 2 business days) or write to:

P.O. Box 10055
Hyattsville, MD 20782-8055

This step is important because the incident command may provide invaluable data about what is happening and additional resources before you attempt to return to or enter your home or business.

Structural Damage and Debris

Damage to a home or business from a tornado or other natural disaster can be obvious or hidden, so be aware of possible structural, electrical, or gas-leak hazards. Tornadoes frequently tear off roofs, shatter windows, and leave homes or businesses susceptible to water damage. If you have left the area where the damage from a disaster occurred before returning to your home or business, be sure that local officials have declared that it is safe to enter your community.

Before entering your home or business, look outside for damaged power lines, gas lines, foundation cracks, and other exterior damage. If power lines are down outside your home, do not step in puddles or standing water. Approach entrances carefully. Parts of your home may be collapsed or damaged. See if porch roofs and overhangs have all their supports. Try to look inside to check the ceiling and floor for signs of sagging. Water may be trapped in the ceiling, or floors may be unsafe to walk on. Be sure the building is structurally sound. Avoid inspecting your home or business in the dark, unless necessary, and if you must, use a flashlight rather than a candle or torch to avoid the risk of fire or explosion.

In addition to structural damage concerns, common causes of injury after a tornado include stepping on nails; falling objects; eye injuries from sawdust while using chainsaws, and heavy, rolling objects. Wear sturdy shoes or boots, long sleeves, and gloves, and always wear eye protection such as safety glasses when there is a potential for flying particles and debris.

In general, if you suspect any damage to your home, shut off electrical power, natural gas, and propane tanks to avoid fire, electrocution, or explosions, and do not enter until you are assured it is safe to do so. Contact your local city or county building inspector for information on structural safety codes and standards.

Here are some useful resources to recognize and address these kinds of hazards:

  • Centers for Disease Control and Prevention
    After a Tornado
    Information about various hazards found after a tornado.
  • Virginia Tech Emergency Management
    After a Tornado
Electrical Hazards

Electrical power lines and circuits may have been damaged in a disaster, so look out for fallen wires and take caution when moving about. If a power line falls on your car while driving, stay inside and drive away from the line. Avoid touching any metal or wet object. Be especially cautious of stepping into the water because live electrical lines may have fallen into the water and created an electric shock hazard. Never use electrical tools when you are standing in water. If possible and safe, turn off the breaker or remove the fuses in your home when your power is out, especially before connecting a generator to your home’s circuit.

Gasoline or diesel-powered generators must be installed and used correctly. If it is necessary to connect a generator to house wiring, have a qualified electrician install appropriate equipment such as an approved automatic interrupt device to prevent a possible fire if your power is suddenly restored while operating the generator. It would be preferable to have the interrupt device installed before the disaster when resources and trained electricians are widely available. Check the generator’s maximum amperage load and do not exceed it. Always place these generators outside and away from the structure to prevent carbon monoxide poisoning.

If thunderstorms occur, seek a sturdy shelter or a car, or stay low to the ground outdoors. Avoid standing near a tree in a thunderstorm. If you are indoors during a thunderstorm, turn off computers and appliances.

Additional guidance for homeowners and small business owners is provided at:

Sources of technical guidance for the industrial hygienist include:

Natural Gas and Other Fuels

Many modern homes contain gas-fired appliances such as water heaters, furnaces, and cooking surfaces. The gas used as fuel is always flammable and may ignite in the presence of an ignition source such as a lighter or other spark-producing devices. Flammable fuel service to a home may include natural gas, propane, or fuel oil. Each service may become damaged due to physical damage to a home, such as from a tornado or from other events that displace the home slightly, such as an earthquake. Such damage may cause a fuel leak in the home that may be difficult to detect.

An inadvertent ignition source or spark may ignite a fuel leak, resulting in an explosion and further damage to the occupants' structure and injury. As a result, the home distribution and fuel delivery systems should be inspected immediately following an event that resulted in or could have resulted in physical damage to the piping or fuel distribution structure inside or immediately outside the home.

Such an inspection should occur with the power disconnected and should include the use of a direct-reading combustible gas or volatile organic compound (VOC) detector. The inspection should start at the fuel delivery source - such as a gas meter or propane storage tank - shut off.

Here are some useful resources to recognize and address these kinds of hazards:

Technical Resources for the IH/OEHS include:

Hazardous Materials (Asbestos, Lead, Petroleum Products, etc.)

Hazardous materials and conditions may be present due to damaged building materials containing lead or asbestos as well as sewage-contaminated items or hazardous materials such as chemicals or cleaning products. In many cases, these building materials are damaged and dislodged during a natural disaster, resulting in the potential for airborne exposure to fibers and particles. Homeowners should be aware of this potential, and they should take extra precautions when encountering these materials.

Also, the release of petroleum products, such as heating oil and gasoline stored in the garage or a vehicle, into a home or other building can lead to airborne contamination and contamination of the building materials, soil, and groundwater.

For homeowners, here are some useful resources to recognize and address these kinds of hazards:

Technical Resources for the IH/OEHS include:

Heat Stress/Cold Stress

Extreme heat or cold conditions may occur during emergencies and be exacerbated by the 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
    • Heatstroke - 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, a red cluster of pimples or small blisters most likely on the neck, upper chest, in the groin area, under the 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 using cool water or cold packs; in low humidity, you can use wet cloths.

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 the inner layers from becoming wet from sweat. Higher insulation values of protective clothing are required for higher wind speeds and lower temperatures in the work area.
  • Wear waterproof boots to protect your feet. If boots have liners, replace them when damp.
  • Wear gloves or preferably mittens to protect hands. Replace when damp.
  • When working outside in the 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 the 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; shallow 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:

Carbon Monoxide

Carbon monoxide (CO) is a colorless, odorless gas that is a combustion byproduct. CO is a chemical asphyxiant that interferes with the body’s ability to re-oxygenate blood and is a common, unfortunate cause of death for many home occupants each year. Homes and commercial structures fueled by hydrocarbons such as natural gas, propane, or fuel oil will generate CO during combustion. This is especially true during peak, seasonal heating demand, such as winter months, when homes may not exchange as much outdoor air.

You or an expert must adequately vent CO from fuel combustion processes such as generators, water heaters, or furnaces outside the home. Physical damage to the home, such as following a tornado or earthquake, may damage or compromise home combustion venting apparatus. Inadequate venting or excessive or poorly mixed combustion may result in a CO build-up in a home and a significant risk to its occupants.

You may find more information on carbon monoxide at:

Water Damage

Rain is often associated with a tornadic activity. If possible, wet building materials and contents should be dried as soon as possible (preferably within 24-48 hours) to prevent mold growth. If the electrical power service is not available in the 24-48 hours following the event, You should expect mold and bacterial contamination in areas where water impaction has occurred.

If the overall amount of impacted materials is less than about 10 square feet, the CDC has guidance for homeowners and renters for entry and clean-up, and the EPA has guidance on how to address mold clean-up on your own.

Be sure to read the label and follow all manufacturer’s recommendations when using any chemical disinfectant for cleaning purposes. Because of the significant risk for adverse respiratory effects and the caustic nature of bleach, You must approach the use of bleach for cleaning purposes with caution. FEMA notes in its guidance on cleaning flooded buildings found that while bleach is convenient as a cleaner and stain remover for hard, non-porous items, it has distinct drawbacks when cleaning water-damaged materials. Many types of bleach are not EPA-registered as a disinfectant. Furthermore, bleach’s effectiveness in killing bacteria and mold is significantly reduced when it comes to residual dirt, which is often present after a disaster. Also, if bleach water comes into contact with electrical components and other metal parts of mechanical systems, it can cause corrosion. Bleach water can also compromise the effectiveness of termite treatments in the soil surrounding the building.

However, if significant mold or other sewage contamination has occurred, it is recommended that business owners and homeowners seek professional guidance before attempting to clean large amounts of contaminated materials. Industrial hygienists and other safety and health professionals can anticipate health and safety concerns and design solutions to prevent exposures using guidelines established by government agencies and institutions such as the Institute of Inspection, Cleaning, and Restoration Certification.

Be cautious when considering hiring contractors to perform mold remediation. The District of Columbia and some states, such as Florida, Maryland, Texas, Louisiana, New Hampshire, New York, require licensure or certification for mold assessors and mold remediators.

You can find guidelines for evaluating contractors at the following sources:

Other sources of guidance related to mold response are:

For the industrial hygienist, it is critical to understand and convey the importance of respiratory protection if clean-up is initiated. Approximately 6 months after Hurricane Katrina, a questionnaire-based study was done on 600 people involved in the clean-up in New Orleans. Respiratory symptom scores increased linearly with exposure in water-damaged homes. Disposable-respirator use was associated with lower odds of exacerbation of moderate or severe symptoms inside water-damaged homes.

Technical guidance for the industrial hygienist includes:

  • Cummings, K.J., J. Cox-Ganser, M.A. Riggs, N. Edwards, G.R.Hobbs, and K. Kreiss: “Health effects of exposure to water-damaged New Orleans homes six months after hurricanes Katrina and Rita.” Am J Public Health 98:869-875 (2008).
Other Biological Hazards and Infectious Agents

Heavy rains during or after a tornado may result in flooding or standing water. Floodwater and standing waters often contain infectious organisms, including gastrointestinal bacteria such as E. coli, Salmonella, and Shigella; hepatitis A virus; and agents of typhoid, paratyphoid, and tetanus. Moreover, pools of standing or stagnant water can become breeding grounds for mosquitoes, increasing the risk of encephalitis, West Nile virus, Zika, or other mosquito-borne diseases. The presence of wild or stray animals in populated areas increases the risk of diseases caused by animal bites (e.g., rabies) and diseases carried by fleas and ticks.

To avoid bacterial and viral exposures, keep children and pets out of standing water and contaminated materials. Hands should be cleaned regularly by either hand-washing with soap and water or using an alcohol-based hand sanitizer (containing 60%-95% alcohol). When hands are visibly soiled or dirty, it is best to wash your hands with soap and clean running water for 20 seconds.

To protect yourself and your family from animal- and insect-related hazards, avoid wild or stray animals, use insect repellent that contains DEET or picaridin, and wear long pants, socks, and long-sleeved shirts—drain standing water in open containers to minimize mosquito breeding places.

Livestock might no longer be confined after a disaster, and the pollution they generate may contaminate surface waters used for drinking. Loose dogs or other roaming animals may be lost, frightened, or hurt and more likely to bite. The CDC recommends that you not feed, approach, or call a dog you do not know.

Rats and mice can spread disease, contaminate food, and destroy property. Remove food sources and other items that can provide shelter for rodents. Keep food and water (including pet food) in containers made of thick plastic, glass, or metal with a tight-fitting lid to keep rodents out. For more information, see the following:

Contaminated drinking water is the top reason for illness after most disasters. If municipal water sources have been impacted, use one of the following for handwashing, drinking, teeth-brushing, and cleaning children’s toys:

  • Bottled water
  • Water that has been boiled for one minute then cooled
  • Water that has been disinfected with 1/8 teaspoon of household bleach per 1 gallon of water or 1/4 teaspoon per gallon of cloudy water (allow it to stand for 30 minutes before use)

The following are resources for home and small business owners:

Technical Resources for the IH/OEHS include:

  • Centers for Disease Control and Prevention: “Infectious disease and dermatologic conditions in evacuees and rescue workers after Hurricane Katrina - multiple states, August-September, 2005.”
    MMWR 54
    :961 (2005).
  • Cummings, K.J., J. Cox-Ganser, M.A. Riggs, N. Edwards, G.R.Hobbs, and K. Kreiss: “Health effects of exposure to water-damaged New Orleans homes six months after hurricanes Katrina and Rita.” Am J Public Health 98:869‒875 (2008).
  • Emerson, J.B., P.B. Keady, T.E. Brewer, N. Clements, E.E. Morgan, J. Awerbuch, and N. Fierer: “Impacts of flood damage on airborne bacteria and fungi in homes after the 2013 Colorado Front Range flood.” Environ Sci Technol 49:2675‒2684 (2015).
  • Jones, E.K., K.G. Sumner, and M. Gochfeld: “Residential flood damage after hurricane Floyd, mold, household remediation, and respiratory health.” Remediation J 24:107‒120 (2013).
  • Ligon, B.L.: “Infectious diseases that pose specific challenges after natural disasters: a review.” Semin Pediatr Infect Dis 17:36‒45 (2006).
  • Lin, C.J., T.J. Wade, and E.D. Hilborn: “Flooding and Clostridium difficile infection: a case-crossover analysis.” Int J Environ Research Public Health 12:6948‒6964 (2015).
  • McKenzie, L.B., N. Ahir, U. Stolz, and N.G. Nelson: “Household cleaning product-related injuries treated in U.S. emergency departments in 1990–2006.” Pediatrics 126:509‒16 (2010).
Radiation from Smoke Detectors and Exit Lighting

After natural disasters, homeowners, business owners, and response personnel may encounter some items containing radioactive materials, most notably smoke detectors and commercial exit lights. Smoke detectors are ubiquitous in most buildings, including residential, commercial, and institutional facilities, since there are code requirements to have them in most jurisdictions. Most smoke detectors use a minimal radioactive source, generally americium-241. However, the level of radiation emitted from a smoke detector is insufficient to create a public health hazard, and there are no federal regulatory requirements for disposal.

Dislocated or damaged smoke detectors may or may not suitable for reinstallation. Because smoke detectors save lives, if there is any doubt about a device's suitability, it may be prudent to exercise precaution and purchase a new smoke detector unit. In general, if damaged or unusable, the recovered smoke detector should be returned to the manufacturer if at all possible. Consult local fire protection agencies for advice.

Tritium exit lights are generally found in commercial and institutional facilities, especially in locations where electrical power is not available or difficult to run. Tritium exit signs are devices similar in appearance to exit signs operated by AC or DC electrical circuits. The difference is that tritium exit signs provide illumination from sealed glass tubes inside the unit containing tritium gas, a radioactive isotope of hydrogen. The tritium gas emits beta particles that interact within the tube to produce illumination.

As long as the glass tube within the sign remains unbroken, there is little risk of radiation exposure. However, if this internal glass tube becomes broken, there is some risk of exposure. If the word “Exit” is not fully or partially illuminated, it indicates that the tritium gas has escaped. As a gas, the tritium will dissipate over time. The rate of dissipation depends on the ventilation rate in the vicinity.

The greatest risk to people occurs when the tritium exit sign first breaks or indicates that there is escaping gas leakage. If a tritium exit sign is broken, leave the area immediately. Consult an industrial hygienist, safety professional, or the state radiation office.

Disposal of tritium exit signs is highly regulated. They must not be disposed of in normal trash or abandoned. If you encounter a displaced tritium exit light, consult with an industrial hygienist or contact the state radiation office in the link above.

You may find additional resources at:

General Response Resources

General disaster relief assistance information is available on these websites: