Chemical Agents Chemical agents are toxic chemicals capable of causing serious harm to human beings. Governments have developed a number of these chemicals specifically for use in warfare, while others, although very dangerous, are used in industry for peaceful purposes. Although most of the examples listed are chemicals that have been used in warfare, there are many industrial toxic chemicals that also fall into the four categories described below when viewed in the context of CBW terrorism. Click on diagram for more information on chemical agents.

Vesicants Vesicants, also known as "blister agents," are agents that cause chemical damage resulting in large blisters on exposed skin. Vesicants irritate the eyes, skin, and the linings of the airways when inhaled and can cause damage that leads to death. These agents were commonly used in World War I and the Iran-Iraq War (1980-1988).

Choking Agents Choking agents are chemical agents that act as lung irritants and can be fatal when inhaled in sufficient quantities. They can also irritate the eyes, nose, and throat. An example of a choking agent is chlorine, which has been used in warfare, but is also commonly used for industrial purposes.

Blood Agents This class of agents generally blocks the processing of oxygen in cells or blood and can quickly lead to death.

Nerve Agents Nerve agents are the most deadly class of chemical weapon agents. They belong to a category of chemicals known as toxic organophosphates. Nerve agents work by blocking the operation of acetylcholinestarase, an enzyme that regulates nerve function. Without acetylcholinestarase, muscles contract uncontrollably until they become exhausted and stop working. Most seriously, this exhaustion can shut down the muscles that control breathing, quickly leaving affected persons unable to breath.

Chlorine is a yellow-green gas with a strong odor of bleach. While these characteristics make it fairly easy to detect and run from, its abundance and affordability make it an attractive agent for terrorists.

Chlorine gas primarily affects the respiratory system and leads to slow death by asphyxiation. Also corrosive to skin and eye tissues, it can cause intense pain, blurred vision, and severe burns.

Removal of victims to uncontaminated area, assistance with breathing and other supportive care.

Phosgene is a colorless gas with an odor of newly mown hay. Phosgene has a density that allows it to stay in the air and low-lying places for fairly long periods of time. It is easy to produce but is highly unstable in storage.

Phosgene results in pulmonary edema (a build-up of fluid in the lungs) that can cause death after a delay of up to 24 hours. In high concentrations, it may also burn the skin and eyes.

Treatment is supportive and would include assistance with breathing and providing oxygen.

At room temperature, hydrogen cyanide is a colorless liquid that evaporates quickly to form a gas, with an odor of bitter almonds. Predominately absorbed through inhalation, it can also be taken up through the skin. Hydrogen cyanide is difficult to use in warfare because it is highly volatile and non-persistent.

Hydrogen cyanide can cause rapid death by asphyxiation-within seconds or minutes of inhalation. Inhalation causes confusion, drowsiness, and shortness of breath, leading to collapse. The chemical can also affect the central nervous system, resulting in impaired respiratory and circulatory functions.

The treatment for cyanide poisoning is primarily speeding-up the body's own ability to excrete cyanide. With the use of antidotes, enzymes transform the compound into a less toxic substance.

Sarin is a highly potent, colorless and odorless liquid. A small droplet can kill a human. Sarin is a volatile compound that disperses quickly and is therefore not persistent. It can produce a vapor that is slightly heavier than air and thus hovers close to the ground.

Sarin may induce death within minutes of exposure. It enters the body by inhalation, ingestion, through the eyes, and the skin. Common symptoms include excessive fluid production, difficulty in breathing, dimness of vision, vomiting, twitching, and headache. The body's involuntary muscle response to sarin is so extreme that exhaustion occurs and muscles can no longer sustain breathing.

Injections of an emergency dose of atropine and other antidotes to prevent muscular spasms and maintain central nervous system integrity; assistance of breathing with ventilation and treatment for blocked airways.

VX is a highly toxic compound in both its liquid and vapor form that attacks the central nervous system. It is considered at least 100 times more toxic by entry through the skin than the nerve agent sarin, and twice as toxic by inhalation. VX is very persistent-it can last for long periods under average weather conditions and for months in very cold conditions.

VX can cause death minutes after exposure. It can enter the body by inhalation, ingestion, through the eyes, and through the skin. Symptoms can vary but typically include excessive fluid production, difficulty in breathing, dimness of vision, nausea, and muscular spasms. Muscles eventually tire to the point they cannot support breathing.

Injections of an emergency dose of atropine and other antidotes to prevent muscular spasms and maintain central nervous system integrity; assistance of breathing with ventilation and treatment for fluid in the lungs.

Lewisite is a clear, oily liquid (with some impure versions ranging from brown to black in color) with a faint odor similar to geraniums.

After exposure to lewisite, a victim experiences immediate burning pain, which in larger doses can lead to death by accumulated fluid in the lungs. Symptoms are accompanied by large blisters on the skin, severe eye damage, restlessness, and weakness.

Treatment is generally supportive, to keep airways working and reduce infection from blistered areas. Some antidotes traditionally called for include British Anti-Lewisite (BAL), antibiotics for eye, lung and skin infections, along with local dressings for chemical wounds.

In its impure form, sulfur mustard is a yellow-brown oily liquid (not a gas, as commonly described) smelling of garlic or mustard. Purer forms are colorless and odorless. The liquid is persistent and the vapors are heavier than air. The odor does not provide adequate warning of detection.

Sulfur mustard acts in a delayed fashion. It is absorbed by the skin, causing redness and large blisters. Exposure to the eyes can be incapacitating and may lead to permanent blindness. Inhalation damages the respiratory tract lining and can cause death by tissue obstruction.

Treatment is generally supportive, to keep the airways working and reduce infection of blistered areas. Antibiotics are used for eye, lung and skin infections, along with local dressings for chemical wounds.