Military specialists have long known that Iraq was using chemical weapons in the Persian Gulf War against Iran, but the extent and effectiveness of that use is only now being determined.
"The use of poison gas was an important factor in Iraqi land victories over Iran this year," one military analyst here said. "This is the horrible and unfortunate lesson of this war."
A Western diplomat said, "The Iraqis used chemical warfare not only in defense but in their offensives this year (and this) contributed to their success and Iranian acceptance of the cease-fire."
Arms control experts, who like diplomatic and military sources would discuss the matter only on condition that they not be identified by name, said they are concerned that other nations, particularly in the Third World, will draw the obvious conclusion: that using chemical weapons is a cheap and efficient way to wage war.
One diplomat, who has specialized in arms control, said: "The only positive aspect of this sorry, widespread use of poison gas is that a ban on chemical warfare may now be placed high on the list of disarmament agendas. Otherwise, it is a bleak picture for all of us."
Over the last four years, Iran has charged repeatedly that Iraq was using gas on the battlefield--nerve, mustard and cyanide gas. On occasion, Iraq has accused Iran of also using gas.
On Friday in New York, the 15-member U.N. Security Council unanimously condemned the use of chemical weapons in the gulf war, expressing dismay over their "more intense and frequent" use against Iran. The resolution asked other nations to halt the export of chemicals used to produce such weapons, the Associated Press reported.
In recent interviews in Baghdad and Tehran, military sources indicated that the Iraqis have used poison gas far more often, and more efficiently, than the Iranians. According to these sources, the Iraqis used chemical weapons liberally in four major attacks this year against the Iranians--at Al Faw, Shalamcheh, the Majnoon Islands and Zubaidat.
By this summer, defense experts believe, the authority to use poison gas on the battlefield had shifted from the supreme command to commanders in the field.
"The Iraqis," one expert said, "have institutionalized the use of poison gas in their field units."
The experts say, too, that Iran's chemical armory is only a small fraction of Iraq's and that this is a key reason why the Iranian command did not retaliate seriously in the use of poison gas.
"The Iraqis," one Western expert observed, "said, in effect, that if you sprinkle us with gas, we will drop a ton on you. The Iranians got the message."
Visitors to Tehran earlier this year found residents worried that the next missile attack by Iraq might involve chemical weapons, which they feared more than high explosives.
Perhaps more important, according to defense attaches, Iran's front-line soldiers developed a dread of poison gas, and their morale suffered as a result.
The Iraqis are also reported to have used what is known as CS riot gas, a nonpoisonous but very disagreeable form of tear gas. This is said to have been effective because Iranian soldiers could not tell the difference between it and the lethal gases.
Not until July did the Iraqis acknowledge that they were using poison gas, and then they defended it as the only way to prevent their country from being overrun by hordes of fanatical Iranians.
"No matter how many Iranians were killed in their mass attacks, they just kept coming," a military specialist here said. "This is the Iraqi defense for using poison gas: Their backs were against the wall; the country was in danger of being overrun."
The most notorious use of poison gas in the gulf war, however, was not in those circumstances. It occurred last March in the town of Halabja, in the mountainous northeast of Iraq not far from the Iranian border. Halabja, a community of about 20,000 people, mostly Kurds, was under Iranian attack and the Iraqis ordered it evacuated. But many people were unwilling to leave their homes.
5,000 Civilians Killed
Nevertheless, Iraqi planes dropped chemical bombs on the town and reportedly killed about 5,000 civilians, many of whom had sought shelter in basements. No Iranian casualties were found.
The attack led some experienced observers to conclude that the village was chosen as an object lesson, not so much for the Iranians but for the Kurds, many of whom had been and continue to be in rebellion against the Iraqi regime.
If so, it was a horrifying lesson. Victims died in great pain, their lungs seared, eyes burned, skin blistered, bodies racked with convulsions and nausea. The more fortunate died quickly.
"It was absolutely inexcusable for the Iraqis to use these horrifying weapons at Halabja," a Western diplomat said. "To use poison gas at any time is reprehensible, but against civilians, and your own population at that. . . ."
Used in World War I
Poison gas was widely used in World War I. It was introduced by the Germans and then used by both sides. By the end of the war, gas was said to have killed 90,000 men and disabled 1.2 million others.
In 1925, an accord signed at Geneva outlawed the use of chemical weapons, though not their manufacture. Several governments continued to make and stockpile such weapons.
Poison gas was not used in World War II, or in the Korean War, possibly because of the threat of retaliation. In Vietnam, the United States used CS gas, but no lethal gases.
There have been reports of poison gas being used in Afghanistan and in Southeast Asia, but they have not been substantiated.
The superpowers, and some lesser powers, have built up arsenals of chemical weapons as well as bacterial weapons. The chemical weapons include blood agents, such as cyanogen chloride, which block oxygen and cause suffocation; choking agents, such as chlorine and phosgene, which fill the lungs with fluid and cause death; blistering agents, which sear the skin and cause respiratory problems that are often fatal, and nerve agents, such as Tabun, which attack the central nervous system and can be lethal within 15 minutes.
Variety of Options
Poison gas can be delivered by artillery or aerial bombs, the experts say. There are a variety of options, so that heavier, persistent gases can be fired at the rear echelon and remain effective longer, while lighter gases can be used on front-line targets. The latter dissipate quickly and enable advancing troops to enter the area, without gas masks, as quickly as 30 minutes after the gas attack.
Some governments provide their troops with uniforms treated to repel gas, but in the gulf war, troops on both sides were not even equipped with gas masks. Masks are considered impractical for bearded soldiers in temperatures of 100 degrees and more.
The use of gas in the gulf war has renewed calls by disarmament agencies to seek a global ban on chemical weapons. But a major problem in seeking to prevent the proliferation of such weapons is the fact that the chemicals used in weapons are also used in the manufacture of pesticides, plastics and other industrial products. A factory turning out pesticides can be quickly converted to the production of chemical weapons.
"What the gulf war has shown us," one expert said, "is that cheap chemical weapons do work and that it will be tempting in the future to use them. We have seen the genie let out of the bottle, and if we don't get it back in through agreement, the outlook is grim."