THE US and Soviet Union have made considerable progress toward an agreement between themselves to destroy most of their poison gas arsenals. This pact could well be signed in June, when Soviet President Gorbachev visits the United States for a superpower summit. Major obstacles, however, still block a more comprehensive worldwide treaty banning chemical weapon possession. Such a ban is currently being negotiated by some 40 nations in Geneva.
US officials hold out hope that a world treaty can be signed relatively soon. President Bush has long taken a personal interest in the dangerous spread of chemical weaponry, so ``we're getting a lot of high level pressure on this,'' says one administration official close to the negotiations.
But other observers in Washington claim the US is in fact playing slowdown on the Geneva chemical talks, and concentrating on just dealing with the Soviets. In the White House ``the hunger for chemical weapons control may be satisfied by this bilateral cutback,'' notes Lee Feinstein, senior analyst of the Arms Control Association.
Secretary of State James Baker III and Soviet Foreign Minister Eduard Shevardnadze nailed down much of the US-Soviet chemical agreement when they met in Moscow early in February. They agreed that by June the superpowers should be ready to sign a pact limiting each to ``equal low levels'' of chemical weapons.
The phrase ``equal low levels'' was purposely vague. US officials say the private understanding is that both sides will retain an amount of nerve gas equal to 20 percent of the current US stockpile.
The time frame for the destruction of excess stocks was also left vague. The problem here is that even if both sides agree to get rid of chemical weapons, right now neither has the ability to do so on a widespread scale.
The Soviet's chemical demilitarization facility has been shut down by environmental protest. Construction of US facilities is still in its early stages after years of controversy. One US chemical destruction plant, at Johnston Island in the Pacific, is beginning pilot operations. Ground for another has just been broken in Tooele, Utah.
In their Moscow meetings, Mr. Baker agreed to compare notes on demilitarization technology with the Soviets. The Soviets are eager for US help in this area, apparently because the cache of Western technology is such that ``it will help get things through their environmentalists,'' says a US official.
The US does have a timetable of sorts for its own chemical destruction. Congress has already mandated that 90 percent of the existing stockpile be destroyed by September 1997.
It remains to be seen what the effect of the US and the Soviets striking their own private deal on chemical weapons will be on worldwide negotiations. It could cause the superpowers to lose interest, but it could also create momentum for the Geneva talks, giving them the energy to surmount the remaining hurdles.
As it now stands, the chemical treaty under negotiation at the Conference on Disarmament in Geneva calls for cessation of chemical weapon production, and destruction of all existing poison gas stocks within 10 years of the treaty taking effect.
Major problems remaining include agreement on challenge inspections to avoid against cheating, and creation of an executive council to oversee the treaty's provisions. With 40 nations involved, identification of what factories will be subject to inspection and how political power will be divided on the executive council are issues ``which have eluded solutions for years,'' US Ambassador Stephen Ledogar told the Conference in February.
Critics complain that the real obstacle to reaching a comprehensive treaty is a US position that it might not destroy all its chemical weapons within 10 years after a treaty took effect.
Until ``all nations capable of building chemical weapons'' sign up, President Bush told the UN last year, the US would keep 2 percent of its chemical weapons around as a deterrant arsenal.
This could be interpreted to mean the US intends to keep some nerve gas around indefinitely, as any nation with a rudimentary chemical industry can theoretically make a chemical weapon. ``I don't think anybody believes we're going to get everybody,'' says Elisa Harris, a chemical weapons expert at the Brookings Institution.
US officials contend they are not saying the whole world must join up before they destroy the last nerve gas bomb. With 40 nations negotiating, and almost that many involved as informal observers, there are only a dozen or so nations completely outside the talks that the US worries about.
North Korea is one. ``We have our idea as to what states are important to us,'' a US official says.
Still, Rep. Martin Lancaster (D) of North Carolina, a Congressional observer to the talks, said the US reservation ``remains the major stumbling block to the negotiations'' after visiting with delegations in Geneva.
Last in a series. Other installments ran March 9 and March 16.