Chemical and Biological Weapons

In case of a chemical or biological weapon attack near you, authorities will instruct you on the best course of action. This may be to evacuate the area immediately, to seek shelter at a designated location, or to take immediate shelter where you are and seal the premises. The best way to protect yourself is to take emergency preparedness measures ahead of time and to get medical attention as soon as possible, if needed.


Chemical warfare agents are poisonous vapors, aerosols, liquids or solids that have toxic effects on people, animals or plants. They can be released by bombs, sprayed from aircraft, boats, or vehicles, or used as a liquid to create a hazard to people and the environment. Some chemical agents may be odorless and tasteless. They can have an immediate effect (a few seconds to a few minutes) or a delayed effect (several hours to several days). While potentially lethal, chemical agents are difficult to deliver in lethal concentrations. Outdoors, the agents often dissipate rapidly. Chemical agents are also difficult to produce.

There are six types of agents: Lung-damaging (pulmonary) agents such as phosgene, Cyanide, Vesicants or blister agents such as mustard, Nerve agents such as GA (tabun), GB (sarin), GD (soman), GF, and VX, Incapacitating agents such as BZ, and Riot-control agents (similar to MACE).

WMD Detail: Chemical


Biological agents are organisms or toxins that can kill or incapacitate people, livestock and crops. The three basic groups of biological agents which would likely be used as weapons are bacteria, viruses, and toxins.

  1. Bacteria. Bacteria are small free-living organisms that reproduce by simple division and are easy to grow. The diseases they produce often respond to treatment with antibiotics.
  2. Viruses. Viruses are organisms which require living cells in which to reproduce and are intimately dependent upon the body they infect. Viruses produce diseases which generally do not respond to antibiotics. However, antiviral drugs are sometimes effective.
  3. Toxins. Toxins are poisonous substances found in, and extracted from, living plants, animals, or microorganisms; some toxins can be produced or altered by chemical means. Some toxins can be treated with specific antitoxins and selected drugs.

Most biological agents are difficult to grow and maintain. Many break down quickly when exposed to sunlight and other environmental factors, while others such as anthrax spores are very long lived. They can be dispersed by spraying them in the air, or infecting animals which carry the disease to humans as well through food and water contamination.

Aerosols -- Biological agents are dispersed into the air, forming a fine mist that may drift for miles. Inhaling the agent may cause disease in people or animals.

Animals -- Some diseases are spread by insects and animals, such as fleas, mice, flies, and mosquitoes. Deliberately spreading diseases through livestock is also referred to as agroterrorism.

Food and water contamination -- Some pathogenic organisms and toxins may persist in food and water supplies. Most microbes can be killed, and toxins deactivated, by cooking food and boiling water. Anthrax spores formulated as a white powder were mailed to individuals in the government and media in the fall of 2001. Postal sorting machines and the opening of letters dispersed the spores as aerosols. Several deaths resulted. The effect was to disrupt mail service and to cause a widespread fear of handling delivered mail among the public.

Person-to-person spread of a few infectious agents is also possible. Humans have been the source of infection for smallpox, plague, and the Lassa viruses.

WMD Detail: Biological

What to do to prepare for a chemical or biological attack

Assemble a disaster supply kit (see the "Emergency Planning and Disaster Supplies" chapter for more information) and be sure to include:

  • Battery-powered commercial radio with extra batteries.
  • Non-perishable food and drinking water.
  • Roll of duct tape and scissors.
  • Plastic for doors, windows and vents for the room in which you will shelter in place -- this should be an internal room where you can block out air that may contain hazardous chemical or biological agents. To save critical time during an emergency, sheeting should be pre-measured and cut for each opening.
  • First aid kit.
  • Sanitation supplies including soap, water and bleach.

What to do during a chemical or biological attack

  1. Listen to your radio for instructions from authorities such as whether to remain inside or to evacuate.
  2. If you are instructed to remain in your home, the building where you are, or other shelter during a chemical or biological attack: Turn off all ventilation, including furnaces, air conditioners, vents and fans. Seek shelter in an internal room, preferably one without windows. Seal the room with duct tape and plastic sheeting. Ten square feet of floor space per person will provide sufficient air to prevent carbon dioxide build-up for up to five hours. (See "Shelter" chapter.) Remain in protected areas where toxic vapors are reduced or eliminated, and be sure to take your battery-operated radio with you.
  3. If you are caught in an unprotected area, you should: Attempt to get up-wind of the contaminated area. Attempt to find shelter as quickly as possible. Listen to your radio for official instructions.

What to do after a chemical attack

Immediate symptoms of exposure to chemical agents may include blurred vision, eye irritation, difficulty breathing and nausea. A person affected by a chemical or biological agent requires immediate attention by professional medical personnel. If medical help is not immediately available, decontaminate yourself and assist in decontaminating others. Decontamination is needed within minutes of exposure to minimize health consequences. (However, you should not leave the safety of a shelter to go outdoors to help others until authorities announce it is safe to do so.)

  1. Use extreme caution when helping others who have been exposed to chemical agents: Remove all clothing and other items in contact with the body. Contaminated clothing normally removed over the head should be cut off to avoid contact with the eyes, nose, and mouth. Put into a plastic bag if possible. Decontaminate hands using soap and water. Remove eyeglasses or contact lenses. Put glasses in a pan of household bleach to decontaminate.
  2. Remove all items in contact with the body.
  3. Flush eyes with lots of water.
  4. Gently wash face and hair with soap and water; then thoroughly rinse with water.
  5. Decontaminate other body areas likely to have been contaminated. Blot (do not swab or scrape) with a cloth soaked in soapy water and rinse with clear water.
  6. Change into uncontaminated clothes. Clothing stored in drawers or closets is likely to be uncontaminated.
  7. If possible, proceed to a medical facility for screening.

What to do after a biological attack

In many biological attacks, people will not know they have been exposed to an agent. In such situations, the first evidence of an attack may be when you notice symptoms of the disease caused by an agent exposure, and you should seek immediate medical attention for treatment.

In some situations, like the anthrax letters sent in 2001, people may be alerted to a potential exposure. If this is the case, pay close attention to all official warnings and instructions on how to proceed. The delivery of medical services for a biological event may be handled differently to respond to increased demand. Again, it will be important for you to pay attention to official instructions via radio, television, and emergency alert systems.

If your skin or clothing comes in contact with a visible, potentially infectious substance, you should remove and bag your clothes and personal items and wash yourself with warm soapy water immediately. Put on clean clothes and seek medical assistance.

Nuclear and Radiological Attack

Nuclear explosions can cause deadly effects -- blinding light, intense heat (thermal radiation), initial nuclear radiation, blast, fires started by the heat pulse, and secondary fires caused by the destruction. They also produce radioactive particles called fallout that can be carried by wind for hundreds of miles.

Terrorist use of a radiological dispersion device (RDD) -- often called "dirty nuke" or "dirty bomb" -- is considered far more likely than use of a nuclear device. These radiological weapons are a combination of conventional explosives and radioactive material designed to scatter dangerous and sub-lethal amounts of radioactive material over a general area. Such radiological weapons appeal to terrorists because they require very little technical knowledge to build and deploy compared to that of a nuclear device. Also, these radioactive materials, used widely in medicine, agriculture, industry and research, are much more readily available and easy to obtain compared to weapons grade uranium or plutonium.

Terrorist use of a nuclear device would probably be limited to a single smaller "suitcase" weapon. The strength of such a weapon would be in the range of the bombs used during World War II. The nature of the effects would be the same as a weapon delivered by an inter-continental missile, but the area and severity of the effects would be significantly more limited.

There is no way of knowing how much warning time there would be before an attack by a terrorist using a nuclear or radiological weapon. A surprise attack remains a possibility.

The danger of a massive strategic nuclear attack on the United States involving many weapons receded with the end of the Cold War. However, some terrorists have been supported by nations that have nuclear weapons programs.

If there were threat of an attack from a hostile nation, people living near potential targets could be advised to evacuate or they could decide on their own to evacuate to an area not considered a likely target. Protection from radioactive fallout would require taking shelter in an underground area, or in the middle of a large building.

In general, potential targets include:

  • Strategic missile sites and military bases.
  • Centers of government such as Washington, D.C., and state capitals.
  • Important transportation and communication centers.
  • Manufacturing, industrial, technology and financial centers.
  • Petroleum refineries, electrical power plants and chemical plants.
  • Major ports and airfields.

Taking shelter during a nuclear attack is absolutely necessary. There are two kinds of shelters -- blast and fallout.

Blast shelters offer some protection against blast pressure, initial radiation, heat and fire, but even a blast shelter could not withstand a direct hit from a nuclear detonation.

Fallout shelters do not need to be specially constructed for that purpose. They can be any protected space, provided that the walls and roof are thick and dense enough to absorb the radiation given off by fallout particles. The three protective factors of a fallout shelter are shielding, distance, and time.

Shielding. The more heavy, dense materials -- thick walls, concrete, bricks, books and earth -- between you and the fallout particles, the better.

Distance. The more distance between you and the fallout particles, the better. An underground area, such as a home or office building basement, offers more protection than the first floor of a building. A floor near the middle of a high-rise may be better, depending on what is nearby at that level on which significant fallout particles would collect. Flat roofs collect fallout particles so the top floor is not a good choice, nor is a floor adjacent to a neighboring flat roof.

Time. Fallout radiation loses its intensity fairly rapidly. In time, you will be able to leave the fallout shelter. Radioactive fallout poses the greatest threat to people during the first two weeks, by which time it has declined to about 1% of its initial radiation level.

Remember that any protection, however temporary, is better than none at all, and the more shielding, distance and time you can take advantage of, the better.

WMD Detail: Radiological

WMD Detail: Electromagnetic Pulse

What to do before a nuclear or radiological attack

  1. Learn the warning signals and all sources of warning used in your community. Make sure you know what the signals are, what they mean, how they will be used, and what you should do if you hear them.
  2. Assemble and maintain a disaster supply kit with food, water, medications, fuel and personal items adequate for up to 2 weeks-the more the better. (See the "Emergency Planning and Disaster Supplies" chapter for more information).
  3. Find out what public buildings in your community may have been designated as fallout shelters. It may have been years ago, but start there, and learn which buildings are still in use and could be designated as shelters again. Call your local emergency management office. Look for yellow and black fallout shelter signs on public buildings. Note: With the end of the Cold War, many of the signs have been removed from the buildings previously designated. If no noticeable or official designations have been made, make your own list of potential shelters near your home, workplace and school: basements, or the windowless center area of middle floors in high-rise buildings, as well as subways and tunnels. Give your household clear instructions about where fallout shelters are located and what actions to take in case of attack.
  4. If you live in an apartment building or high-rise, talk to the manager about the safest place in the building for sheltering, and about providing for building occupants until it is safe to go out.
  5. There are few public shelters in many suburban and rural areas. If you are considering building a fallout shelter at home, keep the following in mind. A basement, or any underground area, is the best place to shelter from fallout. Often, few major changes are needed, especially if the structure has two or more stories and its basement-or one corner of it-is below ground. Fallout shelters can be used for storage during non-emergency periods, but only store things there that can be very quickly removed. (When they are removed, dense, heavy items may be used to add to the shielding.) See the "Tornadoes" section in the "Thunderstorms" chapter for information on the "Wind Safe Room," which could be used as shelter in the event of a nuclear detonation or for fallout protection, especially in a home without a basement. All the items you will need for your stay need not be stocked inside the shelter itself but can be stored elsewhere, as long as you can move them quickly to the shelter.
  6. Learn about your community's evacuation plans. Such plans may include evacuation routes, relocation sites, how the public will be notified and transportation options for people who do not own cars and those who have special needs. See the "Evacuation" chapter for more information.
  7. Acquire other emergency preparedness booklets that you may need. See the "For More Information" chapter at the end of this guide.

What to do during a nuclear or radiological attack

  1. Do not look at the flash or fireball-it can blind you.
  2. If you hear an attack warning: Take cover as quickly as you can, BELOW GROUND IF POSSIBLE, and stay there unless instructed to do otherwise. If you are caught outside, unable to get inside immediately, take cover behind anything that might offer protection. Lie flat on the ground and cover your head. If the explosion is some distance away, it could take 30 seconds or more for the blast wave to hit.
  3. Protect yourself from radioactive fallout. If you are close enough to see the brilliant flash of a nuclear explosion, the fallout will arrive in about 20 minutes. Take shelter, even if you are many miles from ground zero-radioactive fallout can be carried by the winds for hundreds of miles. Remember the three protective factors: shielding, distance and time.
  4. Keep a battery-powered radio with you, and listen for official information. Follow the instructions given. Local instructions should always take precedence: officials on the ground know the local situation best.

What to do after a nuclear or radiological attack

In a public or home shelter:

  1. Do not leave the shelter until officials say it is safe. Follow their instructions when leaving.
  2. If in a fallout shelter, stay in your shelter until local authorities tell you it is permissible or advisable to leave. The length of your stay can range from a day or two to four weeks. Contamination from a radiological dispersion device could affect a wide area, depending on the amount of conventional explosives used, the quantity of radioactive material and atmospheric conditions. A "suitcase" terrorist nuclear device detonated at or near ground level would produce heavy fallout from the dirt and debris sucked up into the mushroom cloud. A missile-delivered nuclear weapon from a hostile nation would probably cause an explosion many times more powerful than a suitcase bomb, and provide a greater cloud of radioactive fallout. The decay rate of the radioactive fallout would be the same, making it necessary for those in the areas with highest radiation levels to remain in shelter for up to a month. The heaviest fallout would be limited to the area at or downwind from the explosion, and 80% of the fallout would occur during the first 24 hours. Because of these facts and the very limited number of weapons terrorists could detonate, most of the country would not be affected by fallout. People in most of the areas that would be affected could be allowed to come out of shelter and, if necessary, evacuate to unaffected areas within a few days.
  3. Although it may be difficult, make every effort to maintain sanitary conditions in your shelter space.
  4. Water and food may be scarce. Use them prudently but do not impose severe rationing, especially for children, the ill or elderly.
  5. Cooperate with shelter managers. Living with many people in confined space can be difficult and unpleasant.

Returning to your home

  1. Keep listening to the radio for news about what to do, where to go, and places to avoid.
  2. If your home was within the range of a bomb's shock wave, or you live in a high-rise or other apartment building that experienced a non-nuclear explosion, check first for any sign of collapse or damage, such as: toppling chimneys, falling bricks, collapsing walls, plaster falling from ceilings. fallen light fixtures, pictures and mirrors. broken glass from windows. overturned bookcases, wall units or other fixtures. fires from broken chimneys. ruptured gas and electric lines.
  3. Immediately clean up spilled medicines, drugs, flammable liquids, and other potentially hazardous materials.
  4. Listen to your battery-powered radio for instructions and information about community services.
  5. Monitor the radio and your television for information on assistance that may be provided. Local, state and federal governments and other organizations will help meet emergency needs and help you recover from damage and losses.
  6. The danger may be aggravated by broken water mains and fallen power lines.
  7. If you turned gas, water and electricity off at the main valves and switch before you went to shelter: Do not turn the gas back on. The gas company will turn it back on for you or you will receive other instructions. Turn the water back on at the main valve only after you know the water system is working and water is not contaminated. Turn electricity back on at the main switch only after you know the wiring is undamaged in your home and the community electrical system is functioning. Check to see that sewage lines are intact before using sanitary facilities.
  8. Stay away from damaged areas.
  9. Stay away from areas marked "radiation hazard" or "HAZMAT."