WITH U.S. FORCES, SAUDI ARABIA, DEC. 13 -- Poison gas strikes fear in the hearts of the uninitiated, but the experts of Operation Desert Shield agree that it is a poor way to make war -- inefficient, awkward and relatively harmless. An artillery shell is likely to kill many more U.S. soldiers than a canister of nerve gas.

Demystifying chemical warfare -- a significant weapon in the arsenal of Iraqi President Saddam Hussein -- is an important objective in Desert Shield training. With proper preparation, experts believe, casualties from chemical warfare can be minimized. Poison gas ceases to be a threat and becomes merely a nuisance.

Yet while U.S. forces are confident they can avoid major casualties from the poison gas itself, chemical warfare poses many secondary problems: how to treat contaminated soldiers who have other wounds; how to decontaminate large numbers of soldiers when it takes 15 minutes to decontaminate each one; how to fight a desert war wearing a gas mask and an impermeable chemical suit in an environment where daytime temperatures, even in the dead of winter, routinely surpass 80 degrees.

Treatment, acknowledged Cmdr. Thad Zajdowicz, chief of internal medicine and infectious diseases at the Navy's Fleet Hospital 5 here, can be "very cumbersome," which "does worsen the equation." Ultimately, he added, it is difficult to know how countermeasures will work, because "I don't have first-hand experience in the front line."

Nor do any of the other Desert Shield soldiers. Iraq is known to possess both nerve gas and mustard gas, a blistering agent, and is known to have used both against Iranian forces during the 1980-88 Iran-Iraq war and against Kurdish civilians in northern Iraq in the late 1980s.

The use of chemical weapons was outlawed in a series of Geneva disarmament conferences in the 1920s. The United States, all of its Western allies and Iraq are among the signatories of the 1925 treaty that grew out of the conferences.

Western nations have not encountered mustard gas since World War I, in which both sides used poison gas extensively. Nerve gas, invented in Germany in the 1930s, has never served as a tactical weapon in any war involving the United States.

Unfamiliarity, coupled with the appalling history of poison gas, has created a chemical warfare myth that in one sense is far more dangerous than reality. "Much of the problem," noted Zajdowicz, "is anxiety."

Dispelling anxiety is part of Zajdowicz's job. He and other experts note that only 3 percent of the Iranians contaminated with nerve gas during the Iran-Iraq war died, many because they could not fit masks over beards worn for religious purposes. "Poison gas is not a particularly effective or efficient way to make war," Zajdowicz said.

Wearing a protective suit, and with help from special detection vehicles and instruments, soldiers are taught to navigate contaminated areas easily and without fear.

At the same time, new countermeasures and treatments are being developed. In late November, for instance, U.S. military forces began distributing the tranquilizer diazepan -- more commonly known by its trade name Valium -- as an antidote to the terminal symptoms of nerve gas.

"Diazepan is a new part of the doctrine, but the doctrine itself has not changed," said Zajdowicz. "It's a question of being prepared for what needs to be done."

Despite their confidence, however, Zajdowicz and others emphasize that chemical warfare can have a grim effect on the unschooled and the unwary. For them, myth can become reality.

Nerve gases, known generically as "G-agents," are chemically akin to common organo-phosphate agricultural pesticides. Tabun, the nerve agent used by Iraq, is similar to the pesticide malathion and can be made just as easily.

Tabun attacks the nervous system in three stages, first causing a runny nose, salivation, tightness in the chest and dim vision. Later, victims experience headache, dizziness, sweating, nausea, involuntary defecation and urination. In the final stage, the gas attacks the central nervous system, producing muscle spasms, convulsions, coma and, if left untreated, death.

The basic antidote to nerve gas is atropine, a venerable drug once made from the deadly nightshade plant and used in Shakespearean times as a beauty aid to enlarge the pupils of girls' eyes. It was called belladonna -- "beautiful lady" in Italian -- and taken in large doses is itself a poison.

Soldiers feeling the early effects of nerve gas are instructed to give themselves one to three injections of atropine, carried as part of their chemical warfare kits. Atropine is a direct antagonist of nerve gas and can reverse its effects immediately, restoring vision (nerve gas contracts the pupils of the eyes) and halting involuntary loss of body fluids. Injection of a second drug, pralidoxine chloride, restores the internal chemical balance upset by the gas.

"With mild exposure, a soldier can treat and cure himself in the field," Zajdowicz said.

Once the symptoms have progressed to the third stage, however, atropine is not effective. Valium is, experts have recently discovered, and Zajdowicz said soldiers are being instructed to administer it to anyone with nerve gas seizures.

Mustard gas, also called blister gas or H-agent, causes completely different problems. An oil-based mist, it splashes in combined liquid-gas form and can produce large, painful blisters within hours of contact with the skin. Mustard gas is most dangerous when inhaled, for a blister forms in the windpipe and can smother the victim or cause fatal pneumonia over a period of weeks.

U.S. experts instruct soldiers to treat mustard gas contamination as quickly as possible with concentrated solutions of chlorine bleach, a powerful alkaline substance that neutralizes the gas. Once formed, blisters can be treated like burns, Zajdowicz said, but healing takes a much longer time.

The most effective way to spread chemical agents, experts say, would be to spray them from a slow-moving plane, such as a crop-duster. Lacking this option, the Iraqis are believed to be capable of delivering gas either in bombs, artillery shells or Scud surface-to-surface missiles, none of which has proved particularly accurate or effective.

A Scud, said one British expert, can carry about 150 quarts of liquid and could contaminate an area of about 10,000 square yards. The expert likened the effect to that of a large garden sprinkler.

A cloud of nerve gas, the expert said, could spread about three miles downwind in a cloud two miles wide. Fortunately for Desert Shield forces, said Zajdowicz, the gas's virulence is short-lived. The combination of wind, sun and rapidly changing temperatures, all of which the Arabian desert has in abundance, would dissipate and neutralize the gas in a matter of hours.

Mustard gas, on the other hand, can linger for days or even weeks in cooler climates. Victims of mustard attacks in Iraqi Kurdistan reported burns and blistering long after the original attack.

The U.S. armed forces' basic chemical warfare countermeasure is an elaborate hooded chemical suit and gas mask designed to cover every part of a soldier's body with an impermeable shield. The entire outfit costs $230.85.

Soldiers wear the suit over their regular uniform and carry it into battle along with mask, gloves and "overboots" that resemble galoshes. Each soldier has two suits with him at all times and a third stowed in his base camp. With prior warning, soldiers don the suit piecemeal, conforming to a five-step chemical alert designed to have everyone fully dressed well before an attack is actually launched.

The very factor that makes the suit effective -- a charcoal lining that renders it airtight -- is also its biggest drawback. The suit holds heat, a shortcoming that didn't matter in an East-West war in temperate Europe, where planners envisioned chemical weapons were most likely to be used.

But in the Saudi desert, where summer temperatures reach 120 degrees every day, using the suit is like being in a sweat box. Zajdowicz noted that winter is much cooler -- in the 80s during the day, around 50 at night.

Still, fighting in a chemical suit, according to everyone consulted, would be awkward and uncomfortable. One Army manual says the suit "swiftly dehydrates the wearer; hampers voice communications, lacks means to dispose of bodily waste, {and is} extremely uncomfortable in 100-plus degree temperature."

Decontamination is a second stumbling block. Soldiers use an elaborate procedure to undress and scrub with chlorinated water in large washing sheds. The process, a virtual human carwash, takes 15 minutes for someone who is cleaning himself without help. Several hundred contaminated people could be washing down for hours.

Chemical warfare thus has the potential to put large numbers of soldiers out of action for long periods of time even without causing casualties. To minimize these bottlenecks, the army has a "decontamination when you can" procedure. Soldiers wearing suits in the field move through or around decontaminated areas, avoiding dehydration by drinking water steadily through straws mounted in their protective masks. They go to a decontamination station only after another unit relieves them.

For those who are wounded as well as contaminated, however, the danger multiplies, Zajdowicz said, and there is no easy answer.

"The concept of triage must apply," Zajdowicz said. Contaminated patients likely to die of their wounds will be made as comfortable as possible and set aside. Lightly wounded soldiers in no danger will also be set aside to wait for treatment. Seriously wounded patients will be decontaminated first.

In no case will a wounded victim be treated before he is decontaminated. To do so, Zajdowicz said, would be to risk contaminating doctors, other patients and entire hospitals full of medical equipment.


Face Masks

Most important defense against contamination, since lungs are about 100 times more sensitive to poison than any other part of body. Active ingredient in masks is charcoal, which reduces almost to zero concentration of chemicals in the air.

Different masks for ground personnel, combat vehicle crews and aviators, but all are equipped with drinking attachment and voice transmitter.

Filter at front removes aerosols and smokes.

Mask covers face. Protective rubber and nylon hood covers parts of head not covered by mask, and tucks under jacket.

Masks must be properly fitted to protect the wearer.


Lightweight two-piece suit weighs just over 4 pounds. The camouflage or olive green jacket and pants "breath," allowing some heat and perspiration to pass out of the material and away from the wearer.

Outer layer of cotton and nylon twill is treated to repel oil and water.

Inner layer of polyurethane foam is impregnanted with activated charcoal.

Soldiers also don gloves, overboots and hoods made of butyl rubber.

In temperatures above 80 degrees Fahrenheit, soldiers with full protection must limit periods of heavy exertion.


U.S. troops have devices capable of detecting all known chemical warfare agents, including:

Specially-treated detection paper that changes color upon contact with chemical agents.

Field alarms that sound in presence of mustard or nerve agents.

British-designed, hand-held electronic Chemical Agent Monitors (CAMs). The lightweight devices detect presence or mustard gas or nerve agents.

SOURCES: The Washington Post; Center for Defense Information; Matthew Meselson, Harvard University