His gas mask would not fit tightly enough, so Mohammed Akbari shaved off his thick, black beard.
The Iranian officer, fighting in 1985 on one of the most gruesome front lines in the Iran-Iraq war, thought he was ready for any chemical weapon that Saddam Hussein's forces could throw his way. Day and night, he wore a special protective suit.
"The whole area was contaminated, there was always the smell of rotten fish," says the Revolutionary Guard colonel, who is among the largest group of chemical-weapons victims in the world.
Iran's grim experience offers valuable lessons as global concern about mass terror attacks - including chemicals - remains high, and as American troops ready for possible chemical warfare in Iraq. Scientists and doctors have visited Iran to study the effects of these weapons on the survivors and learn better ways to treat victims.
Col. Akbari was exposed one night as he walked toward an artillery battery in the dark - and mustard shells found their mark.
"With chemical weapons, you hear nothing," Akbari says. He turns on an oxygen tank next to his couch at home, and slips on a respirator. "I hurried to take my mask, but I realized it was too late."
His hands were exposed to the blistering agent. His son, born years later, was diagnosed with a nervous disorder attributed to the gas. "Nothing is left of me," Akbari says, pulling at his slack pant legs. "I can't laugh or cry."
Officials in Iran estimate that during the eight-year war 100,000 people were exposed to nerve agents like Sarin and Soman, and blistering agents like mustard gas.
President Bush often lists Iraq's use of these weapons as one reason that Mr. Hussein must be disarmed - though the US helped create Iraq's deadly ar- senal at the time by supplying lethal ingredients, sophisticated facilities, and a green light to fight the Ayatollah Khomeini's uncompromising Islamic regime.
The Organization for the Prohibition of Chemical Weapons (OPCW) in The Hague, responsible for ensuring adherence to the UN-brokered 1997 Chemical Weapons Convention, has already held four clinical courses in Iran for medical experts, and plans another next May.
Brian Davey, head of the OPCW's health and safety branch, says that since Sept. 11, "awareness has surged, as the possibility [of a chemical terrorist attack] has moved from a very low-risk, faraway event to something much more real in people's minds."
Detailed medical records here often date from the first battlefield exposure and treatment. "This provides a body of experience that really doesn't exist anywhere else," Dr. Davey says.
Besides using chemical weapons in the Iran-Iraq war, Baghdad used them against Kurdish cities in northern Iraq in the late 1980s, and to put down an uprising among Shiite Muslims in the south after the 1991 Gulf War.
The USSR used chemical weapons during its occupation of Afghanistan in the 1980s. And US troops used powerful defoliants in Vietnam - and napalm during the Gulf War. But nowhere else has such a large population been so exposed, monitored, and now learned from as in Iran.
"What we learned from this bloody war was how to establish a system for mass disaster: How to treat cases, and how to triage them," says Dr. Hamid Sohrab-Pour, who was a leader of Iran's chemical exposure response team for a decade.
He estimates that 10,000 Iranians died almost immediately, when they came into contact with nerve gas. Of the remaining 90,000 who survived blister-agent attacks, according to official figures, Dr. Sohrab-Pour says officials collected records on 30,000.
Some 5,000 cases, like Colonel Akbari's, are regularly followed up. About 1,000 are still hospitalized frequently, often with chronic health problems.
Sohrab-Pour says he has seen a "significant increase" in lung cancer and other problems - like those found among survivors of chemical attacks in north and south Iraq - but that he can't draw conclusions yet about birth defects or other health issues.
A 1991 CIA report - labeled "not finally evaluated intelligence" - counted 50,000 Iranian casualties during the war, "including thousands of fatalities." The report noted that Iraqi use of chemicals became increasingly effective as the war dragged on: Iraq preempted Iranian offensives by striking staging areas; it integrated chemical weapons into Iraqi tactics, and used "mass nerve agent strikes as an integral part of offensives."
Iran was "not prepared to fight in a chemical environment," the CIA report said. Many soldiers lacked gas masks, and some with masks "could not obtain a proper fit because of their beards." Another CIA report estimated 8,000 casualties in a single month in 1986.
At the same time - but not mentioned in the CIA document - the US was providing Iraqi forces with satellite intelligence about locations of Iranian troop build-ups, to improve targeting. Also not mentioned is that Iraq's chemical use propelled Iran to develop its own chemical-warfare program.
Survivors say they blame the US as much as the Iraqis for their suffering. "All the chemical-wounded accuse the US, because without them, Iraq couldn't have made chemical weapons," says Akbari, whose younger brother was exposed on another Iranian frontline and died last year. "It was very clear to us that they were giving this intelligence to the Iraqis."
Iran is working closely with the OPCW, and its experience is critical at a time when experts are concerned that chemical, biological, or radiological "dirty bombs" could fall into the hands of terrorists.
Iran's key experience is tackling high numbers of casualties after chemical contamination - a challenge unfamiliar to most civil defense, military, and emergency workers in the West.
"This brings all sorts of new considerations in the field," says the OPCW's Davey. "Your triage needs to be different, your management systems have to cope with it, you have to introduce a whole new concept of decontamination into mass casualty procedures." Learning such techniques firsthand from Iran is invaluable to those who have passed through the OPCW courses here, Davey says. The courses rotate among clinics for the treatment of skin, eyes, and lungs - the three organs most affected by chemicals.
Just as important, however, the courses show the human impact of such weapons. "It brings home the reality, and moves it from a 'what if?' subject to a real subject," Davey says. "In many cases we see a change in motivation - a personal realization that to study these things and be aware is important."