"It would alter the very nature of war and peace, change the face of battle and of civilian life," says Matthew S. Meselson, Cabot Professor of the Natural Sciences and an expert in chemical weaponry. Yet last week Congress agreed to renew chemical weapon production for the first time in ten years while providing the Army with the funds necessary to clear a site for a munitions plant in Arkansas.

Like most discussions of defense policies these days, Congressional debate centered on estimations of American security and Soviet intentions. The Senate clearly decided (52-38) that America was unable to protect itself. But along with Secretary of Defense Harold Brown, who offered testimony to the Senate, Meselson agrees that the United States retains a credible deterrent. "Contrary to popular misconception, our strength is not deteriorating," Meselson says. "We have more than enough nerve gas to force the Warsaw pact countries into putting on masks and suits on the battlefield and that is enough."

Modern chemical weapons are known as nerve gases or nerve agents. They are chemically related to certain pesticides but are far more potent. The first was discovered in Germany in 1936 during research on insecticides, and the military production of that gas, sarin, began almost immediately.

Nerve gases are usually stored as liquid and when released as a vapor or spray of droplets can enter the body by inhalation or by absorption through the skin. The gases work by blocking neurotransmitters, disrupting the central nervous system, inducing vomiting, convulsions and paralysis and finally death from respiratory failure and asphyxia. Exposure 0.4-1 milligram of gas kills within a few minutes. When released in high density nerve gases can persist as an airborne hazard for days or weeks.

But to a greater degree than conventional weapons, it is possible to protect people from the effects of these gases. Respirators, special clothing and air filters are all effective protection. The gas masks currently used by NATO can be put on within ten seconds and worn even during sleep. Antidotes are also available which can save the life of a person receiving a lethal dose if administered immediately.

Although NATO is now training forces to function on contaminated battlefields, "The U.S. has never practiced extended field exercises," says Meselson. "Only thorough training and discipline will provide adequate protection," he adds.

Can the use of chemical weapons win a war? Meselson says, "The last year of World War I saw the use of mustard gas by the Central Axis powers. The Germans used it massively and unilaterally against relatively undefended troops. Official historians say that it was not a decisive weapon."

But nations now have nerve gases far more toxic than mustard gas. In addition, if airfields and ports were under attack--they weren't in World War I--the dangers would be hard to evaluate.

But one fact is clear: those who will be killed by chemical weapons are civilians. Millions would die if a major chemical war broke out in Europe and the ratio of soldiers to civilians would be small.

Meselson puts it slightly differently: "War has always been a formalized conflict that was compartmentalized. There were war zones and there were peace zones. With chemical weapons, one could imagine combat not easily separable from peace."

So why did Congress revive American weapons production which was halted in 1969 when the Nixon Administration unilaterally stopped stockpiling weapons? There are several explanations. First, the breakdown of detente has NATO allies on edge. Second, it is an election year and few Congressmen want to be known as "soft" on defense spending. And last, unconfirmed reports are circulating that the Soviets used chemical weapons in Afghanistan.

But moves have been made toward mutual disarmament. Since 1976, the Soviets and the U.S. have met 12 times for talks concerning prohibitions against chemical weapons, and substantial agreement has been reached on definitions and limitations.

In July, great progress occurred when both nations agreed to allow on-site inspection of facilities by the other during the proposed destruction of existing weapons. This systematic approach replaces the "challenge system" in which only suspected violations are investigated. But the rights and duties of the inspectors and the host country are still under negotiation.

If resolved, and final negotiations proceeded, it would take the U.S. 20 years and $6 billion to destroy our 150,000 ton inventory.

Meanwhile, the development of new weapons continues. A new "Binary" weapons delivery system is in the works. Binary munitions are actual bombs containing two harmless chemicals that when mixed during the flight of the missile, create a lethal gas. This system makes the transport of chemical weapons less hazardous, but its simplified technology might allow other countries to manufacture chemical weapons.

The chemical weapons treaty process is at a critical stage. While the best deterrent may be a strong defensive capability, the new U.S. production could provoke the Soviets into withdrawing from negotiations.

Meselson warns, "We should not consider chemical weapons in an atmosphere of panic. Like most technological advances, inadequate attention has been given to the long term implications of building chemical weapons."

The U.S. does not put as much priority on this issue as it should, Meselson says, adding, "There is still time. But time may be running out.