As Iraq’s War Options Narrow, Risk of Chemical Attack Rises

If Iraq uses chemical weapons against coalition forces, there is only a limited -- albeit highly lethal -- selection of agents it could choose from, primarily mustard gas, Tabun, sarin and VX.

The chemical agents can be dispersed by a variety of methods that are well within Iraq’s grasp, including spraying from airplanes, inclusion in artillery shells and bombs, and dispersal by rockets. Because they are a highly toxic agent that can, if properly dispersed, kill large numbers of people, nerve gases are often called “the poor man’s atomic bomb.”

The oldest commonly used chemical warfare agent is mustard gas, which made its first appearance in the trenches of World War I, causing an estimated 700,000 casualties. It is an oily liquid with a garlicky smell. It evaporates slowly, even in warm weather, causing the area where it is dispersed to be dangerous for several hours.

Mustard gas burns any body tissue that it comes into contact with. Ingested, it is deadlier, weight for weight, than cyanide gas, although its effects may take a few minutes to manifest. Victims who survive suffer from extensive blistering, blindness and severe lung damage.

Iraq is suspected of using mustard gas during its war with Iran in the 1980s and is known to have used it against rebellious Kurds after the 1991 Persian Gulf War.

Iraqi forces are also suspected of having used the nerve agent Tabun against Iranian troops. Also known as GA, Tabun is an oily liquid with a slightly fruity odor that evaporates half as fast as mustard gas, but is much more deadly and acts within seconds. It causes an overstimulation of muscles and glands.

The first symptoms include contraction of the pupils and a tightness in the chest. If the dose is lethal, those symptoms are followed by sweating, involuntary urination and defecation, vomiting, convulsions, paralysis and unconsciousness.

Iraq is also suspected of possessing the nerve gas sarin. Sarin, or GB, and the closely related cyclosarin and soman, or GD, act like Tabun and produce similar effects, but they dissipate much more rapidly. Their effects are triggered primarily by inhalation and not by skin contact. The odorless sarin was used in the 1995 attack on a Tokyo subway, killing about a dozen people and injuring 5,500.

VX is also an odorless nerve gas and causes the same effects as Tabun and sarin, but it is more toxic and much more persistent. VX can be used for long-term contamination of territory.

Although biological agents are unlikely to be used against military forces, Iraq is suspected of having worked on several, including anthrax, smallpox, botulinum and ricin.

Botulinum and ricin are toxins that might be used to poison food or water. Botulinum attacks nerves throughout the body, causing double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth and muscle weakness. It can be fatal.

Ricin, made from castor beans, kills cells by preventing them from synthesizing proteins. Symptoms depend on whether it is inhaled, eaten or injected. In general, it causes the failure of multiple organ systems and death within 36 to 48 hours.

Anthrax is caused by the bacterium Bacillus anthracis. An outbreak would be triggered by dispersal of bacterial spores, which would generally be inhaled. Symptoms usually occur within seven days, starting with a cough and other cold-like symptoms and progressing to breathing problems and shock.

Smallpox is spread by a virus and, once an attack is triggered, would be highly contagious. The incubation period is seven to 17 days, and the first symptoms are fever, malaise, aches and sometimes vomiting, followed by a rash. It is often fatal.