The mystery gas used to end the hostage crisis at a Moscow theatre could be a secret crowd-control weapon, according to research by New Scientist. Such gases are known to be in development by governments who want “non-lethal” ways of dealing with civilians during conflicts.
The gas knocked out the Chechen terrorists and led to the freeing of hundreds of hostages. But it killed all but two of the 117 hostages who died, and nearly all those freed remain in hospital. About 650 people are being treated, and observers fear further deaths and the possibility of permanent brain damage.
The Russian authorities are still refusing to identify the gas it pumped into the theatre early on Saturday. The crisis began last Wednesday when 50 heavily armed Chechens took about 800 people hostage. Shots inside the building raised fears that the terrorists had begun executing the hostages shortly before the theatre was stormed. The terrorist demand for Russian troops to withdraw from Chechnya had not been met.
The Chechens had planted bombs around the theatre and some had large packets of explosive strapped to their chests, ready to detonate if attacked. Security experts say this risk will have led the Russian forces to use the knock-out gas.
But rendering the hostage takers unconscious almost instantly appears to have come at a heavy price. The gas may have been developed as a non-lethal weapon, but the dose needed to incapacitate a young, fit terrorist would be fatal to those older and weaker, especially after three days in captivity.
Weapons experts have suggested a 1950s chemical weapon called 3-quinuclidinyl benzilate, or BZ, may have been used. This causes disorientation and hallucinations and was tested by the US on servicemen in the 1960s.
But according to Christopher Holstege of the University of Virginia, BZ takes an hour to start working and its effects peak at eight hours – whereas the Russian gas worked in seconds. Moreover, a hallucinogen seems a risky choice for terrorists strapped to bombs.
But reports that the victims are pale and weak, with memory loss, and that doctors are treating them with the cholinergic drug physostigmine, suggest that the gas belongs to the same class of anti-cholinergic agents as BZ.
The agents block some receptors for the neurotransmitter acetylcholine. This blocks the normal activity of the parasympathetic nervous system, causing higher heart rate and lack of sweating among many other symptoms. They also cross the blood-brain barrier blocking similar receptors in the brain, causing unconsciousness or disorientation, hallucinations and blocked memory formation.
Physostigmine would not be used to treat the nerve gases sarin, tabun and soman, and Valium or related anti-anxiety drugs.
Vil Mirzayanov, a former Soviet chemical weapons scientist turned campaigner, says the gas was a derivative of BZ developed by Russia during the Cold War.
Such agents should have been destroyed by now under the Chemical Weapons Convention. But the CWC contains what campaigners call a loophole, which allows gases for “law enforcement”.
The continued Russian secrecy about the identity of the gas suggests it may well be a compound of military origin, rather than a medical anaesthetic. Affected hostages are not being allowed to leave the hospital and relatives cannot visit them, possibly to prevent blood samples being taken that would reveal the identity of the gas.