Moscow siege gas is based on heroin, claim doctors

Doctors who examined victims of the Moscow theatre siege believe they were knocked out by an opiate rather than nerve gas, American officials said yesterday.

Officials at the US embassy in Moscow said the doctors, thought to be Dutch or Austrian, said the effects of the gas appeared consistent with an opiate – such as a heroin derivative. Such substances not only kill pain and dull the senses but can also cause coma and death by shutting down breathing and circulation.

But as the Russian military continued to refuse to confirm the components of the gas used to end the weekend siege, despite repeated formal requests, other doctors remained mystified by the effects.

"It remains a puzzle," said Dr Thomas Zilker, a toxicology professor at Munich University Clinic in Germany, who is treating two former hostages. He said the gas did not appear to be a known chemical weapon and could be a secret formula developed by Russia.

The Russian government will not reveal the type of gas because it may face similar attacks in the future, according to Alexei Arbatov, a member of Russia's lower house of the parliament. He described the substance as a "police gas" used to incapacitate the rebels. "In order to be able to use such gas again, the secret could not be disclosed," he said.

Pavel Felgenhauer, an independent security expert, said: "Russian authorities may be refusing to name the gas out of fear of criticism, or even litigation. It may have contained some prohibited compound."

Russia is bound by the 1997 chemical weapons convention, along with 64 other nations, which bans the use of certain substances. Chemical weapons experts have said that it was likely to be a "neuro-paralytic" agent developed in the 1970s, related to sarin and the US chemical warfare gas BZ. But one US expert said an "incapacitating" rather than lethal agent was far more likely.

A former Russian defence ministry official, Viktor Baranets said: "Most likely the agent they chose was the gas known as Kolokol-1, the most promising of all psycho-chemical agents developed by the Soviet special services."

He said the gas, known within Russia's security community for some time, "spreads rapidly across broad areas, and can render a healthy person completely unconscious in 1 to 3 seconds", but people with weak hearts or prone to vomiting could die from inhaling it.

Moscow's chief medical officer Andrei Seltsovsky said yesterday the gas would not have been fatal if the victims had been healthy, and had not been deprived of food, water and exercise during their two and a half days of captivity.

Other Russian experts thought the main ingredient of the gas was probably a powerful tranquilliser such as Valium. "Chemical weapons that cause temporary paralysis are not banned under international law," said Lev Fyodorov, a former Soviet chemical weapons scientist who now heads the independent Council for Chemical Security in Moscow.

Mr Fyodorov said the gas was developed in a secret KGB laboratory in Leningrad during the 1970s. Methods of dispersing it were tested on an unwitting Soviet public in the Moscow metro in the following decade, he said, adding that the authorities may have mistakenly used too strong a dose.

"There is a well-known Russian habit of overdoing things. The doses they injected into the theatre were far too great; they were elephantine," he said. "They did not take into account that many people inside the theatre were from risk groups, such as pregnant women, people with heart, kidney or liver problems, elderly people and so on."