Gas Used in Crisis Troubles Experts

The decision by Russian security forces to use a powerful chemical agent to end the confrontation with Chechen rebels in a Moscow theater crossed a line that U.S. experts concluded years ago could lead to disaster in such a situation.

Although specific details about what kind of gas Russian commandos pumped into the theater remain unknown, the extent of the casualties and what is known about the symptoms of those who were hospitalized appear consistent with nerve gas or a “neuroparalytic” chemical.

But U.S. scientists have long feared that it would be impossible to administer a dose of such chemicals that would disable people without killing them.

That might not matter against enemy troops in wartime, but it could be critical in a situation such as the one in the Russian capital.

In the Moscow showdown, commandos freed about 700 hostages by storming the theater after filling the building with gas that disabled many inside. But many of the scores who died apparently were killed by the gas, not by gunfire or explosives.

The United States announced an end to the development of nerve gas and other chemical weapons as part of the Chemical Weapons Convention of 1997.

But a government scientist who specializes in chemical and biological weapons said Saturday that what was known about the Moscow episode was in many ways consistent with use of a nerve agent such as sarin, VX or soman.

These agents could kill or hospitalize survivors, said this expert, a physician.

Sarin, soman, VX and related compounds belong to a family of so-called nerve agents known as organophosphates. They cause the muscles controlling the respiratory system, bladder and other organs to seize up and clench.

The agents also can reach the brain and cause seizures.

Moreover, although antidotes for these agents exist, victims can also overdose on the antidotes, with damaging or even lethal results.

It is possible that chemical agents containing Valium or other tranquilizers were employed, but they would probably have had to be used in huge quantities to prove fatal. Anesthetics are also a possibility, but they are not always quick-acting, as the gas used in Moscow seems to have been.

“If there are that many people still in the hospital sick, that sounds like a classic organophosphate nerve agent rather than Valium or narcotics or anesthetics,” the physician said.

U.S. experts stressed that analysis of what happened in Moscow cannot be done with certainty in the absence of specific details about what chemicals were used.

One specialist said the Soviet Union went further than U.S. researchers in studying and developing nerve agents and other chemical agents.

On a wartime battlefield, experts said, the question of dosage would not be critical because the goal would be to destroy an enemy force. And the United States developed and produced huge quantities of nerve gas and other chemical agents capable of doing that.

The situation would be quite different if such agents were used on civilians in peacetime, where the goal would be to incapacitate but not kill.

The problem with organophosphates is that they are so powerful that an overdose can be devastating, and calibrating a disabling dose for an individual is difficult; for crowds of people in an uncontrolled environment, the problem would be greater still.

“It’s real difficult to titrate between a lethal dose and one that’s merely incapacitating,” the U.S. government scientist said.

Experts added, however, that Russian researchers may have gone further than their American counterparts and developed agents they considered sufficiently safe to use, particularly in dire circumstances such as a threat to execute hostages.

In the human body, at the points where nerve endings meet voluntary muscles, the nerves release a chemical called acetylcholine, which stimulates the muscles. The acetylcholine is then broken down by the enzyme acetylcholinesterase so that the muscle relaxes.

The alternating interaction allows the lungs and other organs to function.

Nerve gases such as soman block acetylcholinesterase. The result is continuous stimulation of the voluntary muscles, because there is no chemical to break the acetylcholine down.

If contact with nerve gas is not immediately fatal, a window of a few hours exists in which to administer the antidote and reverse the effects of the nerve agent. Antidotes either inhibit the release of new acetylcholine or else knock the blocking chemical off the acetylcholinesterase. These antidotes include Atropine and Pralidoxime.

“The Russians had probably a much more aggressive organophosphate nerve agent program than we did when we had chemical weapons. We probably stopped with VX as our most potent agent,” the U.S. government scientist said. “It’s clear that the Soviets did work in other kinds of related agents that could overcome some of the problems of their use on the battlefield.... They had a much more robust program in finding new organophosphates.”

“It’s no surprise that the Russians have that kind of stuff,” Ron Madrid, a former Marine and an expert on nonlethal weaponry at Pennsylvania State University, told Associated Press.

“They spent 30 years putting it together. We’re prevented from doing that by treaty and executive order.”