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Homeland Security

Chemical Attack: What to Do

Facts about Toxins of Biological Origin

Agents such as botulinum toxin and ricin are toxins produced by plants, animals, and bacteria. Other examples include toxins from dangerous algal blooms and snake venoms. These substances can be gathered in nature, or alternatively, created in labs. Unlike biological agents, they do not reproduce or spread from person to person. Unlike other chemical agents, they are not volatile (they do not vaporize) and tend to be more toxic on a weight basis.

Botulinum toxin is a nerve toxin produced by bacteria. It causes botulism, a rare but serious paralytic illness that can be fatal. The three naturally-occuring forms of the illness are foodborne, infant, and wound botulism. An antitoxin is available to treat botulism, but must be administered within hours of exposure.

Ricin is a toxin from castor beans that is part of the waste produced when castor oil is made. It is very toxic—a dose the size of the head of a pin could be lethal, but only if injected. Ricin is not absorbed by the skin and is not effective when eaten or inhaled except in impractically large amounts. Ricin was reportedly found in Al Qaeda caves in Afghanistan in the 1980s. There is no antidote.

Practical Steps

If the release is inside a building or a closed space, people should:

  1. Do whatever it takes to find clean air quickly: exit the building if they do so without passing through the contaminated area or break a window to access clean air.
  2. Remove outer clothing and place it in a sealed plastic bag. 
  3. Wash with soap (preferably liquid) and water. Flush skin with lots of water; flush irritated eyes with water.
  4. Put on clean clothes.
  5. Seek medical attention if they have been exposed, even if they have no immediate symptoms.

If they are near an outdoor chemical release, people should:

  1. Avoid any obvious plume or vapor cloud.
  2. Walk away from the site and into a building in order to shelter-in-place. 
  3. Bring family and pets inside. 
  4. Lock doors, close windows, air vents, and fireplace dampers. 
  5. Turn off fans, air conditioning, and forced air heating systems. 
  6. Go into a room with as few windows as possible. Seal the room to create a temporary barrier between people and the contaminated air outside.
  7. Seal all windows, doors, and air vents with plastic sheeting and duct tape. 
  8. Improvise with what is on hand to seal gaps to create a barrier from any contamination.
  9. Watch TV, listen to the radio, or check the Internet often for official news and instructions as they become available.

Decisions Regarding Evacuation

Evacuation as a toxic cloud is passing could result in greater exposures than staying inside. The best course of action will be provided by emergency officials who may use computational models to calculate the path and potential health effects of the toxic cloud.

Medical Treatment

Immediate medical treatment is required for those exhibiting signs and symptoms of exposure to toxic chemicals. (See Table 1)


There are reliable antidotes for nerve agent exposure, which may be available from medical professionals. Some antidotes, such as atropine, pralidoxime chloride (2-PAM chloride), and diazepam, are contained in first responders' medical kits, but larger quantities of these antidotes may be found at hospitals and treatment facilities. A specific antidote kit is available for cyanide, but it may have to be administered in a hospital. Supportive medical care and hospital therapy is required for large exposures to phosgene and chlorine vapor.

Last Published Date: August 9, 2012
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