The Russian hostage crisis was a terrifying field test for a branch of medical science that has long occupied military and law enforcement researchers in the United States and elsewhere: how to incapacitate people without killing them.
And as ghastly as the outcome was - 116 of about 750 hostages were killed by the gas sprayed into the Moscow theater where Chechen extremists held them - American experts say the Russians' plan to use an opiate in aerosol form was probably about the best that could be devised.
They fault Russian authorities, however, for failing to inform medical personnel of the nature of the gas. If enough doctors had been at the scene, equipped with a fast-acting opiate antidote called naloxone, more lives might have been saved, the experts say.
"I think the Russians had a good plan: Knock out these people and take their guns," says Dr. Daniel J. Bochicchio, an assistant professor of anesthesiology and critical care at the University of Maryland School of Medicine who also serves in the Maryland National Guard. "I think the wrong thing to do would have been to go in with guns blazing."
But Bochicchio says there was no excuse for the failure to be ready to treat the drugged hostages.
"They had time to prepare better," he notes. "They should have had doctors, nurses, triage units and plenty of naloxone right at the scene. I saw them taking away unconscious people on buses. That's not the way you do medical evacuation."
Eric Croddy, who studies chemical and biological weapons at the Monterey Institute of International Studies, agrees that the Russians' secrecy drastically delayed treatment. But he says he doubted the United States could have come up with a better way to end the crisis.
"It was a pretty creative approach," says Croddy, author of a book on biological and chemical weapons. In one roughly analogous situation - the 1993 siege of the Branch Davidians compound in Waco, Texas - the U.S. government did not do nearly as well, he says.
In Waco, where cult leader David Koresh was holed up with his followers, authorities used an armored personnel carrier to punch a hole in the building and spray in CS gas, a kind of tear gas. A fire broke out - apparently started by suicidal cult leaders - and nearly everyone inside died. The death toll of 80 included 22 children.
"That would have been a good place to use incapacitating agents," Croddy says. "Comparatively, we did far worse than the Russians."
But the problem in both cases was not an easy one. Despite decades of research, no country has come up with an agent that can quickly and reliably disable everyone in a crowd without killing at least some of them.
The hostage-taking in Moscow posed a particularly difficult challenge. Some of the guerrillas - including the widows of rebels killed by the Russians in their devastating war on the small, mountainous republic of Chechnya - had explosives strapped to their bodies. The agent used would have to be virtually odorless and extremely fast-acting to incapacitate the hostage-takers before they could realize what was happening and blow up the theater.
The Russians clearly chose an aerosol form of some powerful opiate - the class of drugs that includes morphine, heroin and several more powerful synthetic substances - because doctors found that naloxone worked as an antidote. Naloxone, often sold as Narcan, rapidly reverses the dangerous effects of opiates in depressing the central nervous system. It is the drug given in U.S. emergency rooms to heroin addicts who have overdosed.
Some experts suggested that the drug used might be a synthetic opiate called fentanyl, which is 80 to 100 times more potent than morphine, or the related drug sufentanil, which is 1,000 times more powerful than morphine. The opiate may have been combined with other drugs in a cocktail whose formula the Russian military may consider a state secret, or may not want future terrorists to be able to protect themselves against.
In a botched 1997 assassination attempt in Jordan, Israeli agents sprayed fentanyl in the ear of Khaled Meshal, a leader of the radical Palestinian group Hamas. But the agents were caught, and Israel, at the demand of the late King Hussein, supplied an antidote and the secret formula for its deadly fentanyl mixture, designed to be absorbed through the skin, according to press reports at the time.
U.S. military chemical warfare researchers studied several opiates in the 1950s and 1960s, including etorphine, the drug traditionally used with a dart gun to knock out dangerous wild animals, Croddy says.
"But with the opiates, they found there was a very narrow window between the incapacitating dose and the lethal dose, so they gave it up," Croddy says.
That is the problem with virtually all "incapacitants." The dose that will reliably knock out a 200-pound terrorist will often kill a 50-pound child or an adult with heart trouble.
Anesthesiologists search for drugs that have a good "safety ratio," says Bochicchio - an effective dose that is much smaller than the fatal dose.
But knocking people out for surgery is nonetheless a delicate task, he says. During an operation, doctors constantly monitor blood pressure, heart rate and breathing rate, prepared to make moment-by-moment adjustments if there is a problem. In the Moscow theater, the Russian authorities essentially conducted an experiment in mass anesthesia without the usual medical precautions, he says.
The quest for better solutions than the one the Russians used continues in this country.
The Justice Department has a "Less-Than-Lethal" research program, designed to find a way to stop, for example, armed, mentally ill people without shooting them.
The U.S. military, called on in recent years for peacekeeping in hostile places from Haiti to Afghanistan, is putting millions of dollars into devising safe ways to disable people.
One product is a spray 10 times more slippery than ice, which causes a crowd to fall down and stay down, says Marine Capt. Shawn Turner, a spokesman for the Joint Non-Lethal Weapons Directorate. Another is a laser that creates the sensation of intense heat when focused on a person, causing them to turn and run, he says.
At Aberdeen Proving Ground, Army researchers have cooked up other products: a net that shoots out and entangles people, a foam that can rapidly fill a room, nasty-smelling malodorants and even "beach balls" that instantly inflate, forcing people back, says Miguel L. Morales, an Army spokesman.
It was at the old Edgewood Arsenal in Aberdeen that the Army experimented with BZ, an LSD-like hallucinogen that military researchers loaded into bombs and spray devices beginning in the 1950s. BZ remained in the U.S. arsenal until 1990, Morales says, though it was never used.
"It was abandoned because it wasn't reliable," he says. "It worked on some people and not on others."