Moscow Hostage Crisis Chemical Agent

The chemical agent used in the Moscow theatre hostage crisis of 23 October 2002 has never been definitively revealed by the Russian authorities, though many possible identities have been speculated. An incapacitating agent of some kind was used by the Russian authorities in order to subdue the Chechens who had taken control of a crowded theater.

It was reported that efforts to treat victims were complicated because the Russian government refused to inform doctors what type of gas had been used. In the records of the official investigation of the act, the agent is referred to as a certain "gaseous substance", in other cases it is referred to as an "unidentified chemical substance" (conclusions of forensic examination commission, Volumes 30-33 of the criminal case).

At the time, the gas was surmised to be some sort of surgical anesthetic or chemical weapon. Immediately after the siege, Western media speculated widely as to the identity of the substance that was used to end the siege, and chemicals such as the tranquilizer diazepam (Valium), the anticholinergic BZ, the highly potent oripavine-derived Bentley-series opioid etorphine, another highly potent opioid, such as a fentanyl or an analogue thereof, such as 3-methylfentanil, and the anaesthetic halothane were proposed. Foreign embassies in Moscow issued official requests for more information on the gas to aid in treatment, but were publicly ignored. While still refusing to identify the gas, on October 28, 2002 the Russian government informed the U.S. Embassy of some of the gas's effects. Based on this information and examinations of victims, doctors concluded the gas was a morphine derivative. The Russian media reported the drug was Kolokol-1, either mefentanyl or α-methylfentanil dissolved in a halothane base.

Two days after the incident, on October 30, 2002, Russia responded to increasing domestic and international pressure with a statement on the unknown gas by Health Minister Yuri Shevchenko. He identified it as a fentanyl derivative, an extremely powerful opioid. Boris Grebenyuk, the All-Russia Disaster Relief Service chief, said the services used trimethyl phentanylum (3-methylfentanyl, a fentanyl analog that is about 1000 times more potent than morphine, which was manufactured and abused in the former USSR); New Scientist pointed out that 3-methylfentanyl is not a gas but an aerosol. The research made by American scientists into fentanyl derivatives shows that their lethality level surpasses the efficiency of traditional lethal methods: the lethality degree of the chemical weapons used in World War I was 7%, while in the Dubrovka theater it exceeded 15%.

A German toxicology professor who examined several German hostages said that their blood and urine contained halothane, a once-common inhalation anaesthetic which is now seldom used in Western countries, and that it was likely the gas had additional components. No other unusual chemical substances have been detected. However, halothane has a strong odor (although often defined as "pleasant" by comparison with other anesthetic gases). Thus, by the time the whole theatre area would be filled with halothane to a concentration compatible with loss of consciousness (0.5% - 3%), it is likely that Chechens inside would have realized they were being attacked. Additionally, recovery of consciousness is rapid after the flow of gas is interrupted, unlike with high-dose fentanyl administration. Therefore, although halothane might have been a component in the aerosol, it was probably not a major component, or perhaps it was a metabolite of another drug.

Writing in the Moscow daily Komsomolskaya Pravda, Viktor Baranets, a former Russian Defense Ministry official, stated that the Ministry of the Interior knew that any normal riot control agent, such as pepper spray or tear gas, would allow the Chechens time to harm the hostages. They decided to use the strongest agent available. The paper identified the material as a KGB-developed "psycho-chemical gas" known as Kolokol-1, and reported that "the gas had such an influence on Barayev that he couldn't get up from desk". Russian doctors who helped hostages in the first minutes after the siege used a common antidote to fentanyl, naloxone, by injection. But the effects of the fentanyl derivative's application, which can cause chronic diseases, grew acute for the hostages, who had stayed in a closed space without water and food for several days.

Prof. Thomas Zilker and Dr. Mark Wheelis, interviewed in the BBC's "Horizon" documentary series, dispute that the gas could have been based on fentanyl.

Thomas Zilker: It seems to be different from fentanyl, carfentanil and sufentanil but it has to be, it has to have the potency of carfentanil at least because otherwise it wouldn’t work in these circumstance. So the Russians obviously have designed a new fentanyl which we can not detect in the west.

Mark Wheelis: The fact that the Russians did it and got away with a lethality of less than twenty percent suggests to me that very likely there may have been a novel agent with a higher safety margin than normal fentanyl.

Although the exact nature of the active chemical has not been verified, the Russian language newspaper Gazeta claimed that the chemical used had been 3-methylfentanyl, attributing this information to "experts from the Moscow State University chemistry department".