LAST MONTH an international conference meeting in Geneva to review the provisions of the 1972 pact banning biological warfare was thrown into disarray by the announcement in Washington of an apparent violation by the Soviet Union. The alleged incident -- involving an outbreak of deadly anthrax bacteria and the death of about 1,000 people -- had taken place 11 months before, but government spokesmen maintained that the timing of the announcement was coincidental. Sufficient evidence to justify a public statement, they said, had just been received and analyzed.

But then an anonymous intelligence official was quoted in The New York Times as saying that the timing of the announcement was "no accident." His comment lent force to the opinion that the announcement had been fueled by anti-arms-control sentiments inside the government, perhaps by those who wished to sabotage negotiations to limit chemical warfare. The eleventh round of these negotiations just happened to be taking place at the same moment and in the same city as the biological warfare conference.

For more than 50 years, it was generally held that chemical and biological warfare should be controlled by a single treaty. The two were not separated until 1971. But the subsequent development of bioengineering and recombinant DNA techniques further blurred the already thin line between them.Thus, eventually, truly effective control of either biological or chemical warfare will require treaties governing both. And, like the biological convention, the atmosphere surrounding the chemical warfare talks has been soured by repeated -- but still unconfirmed -- allegations that the Soviet Union has used chemical weapons in Laos, in Cambodia and now in Afghanistan.

The chemical warfare talks are important not only because of the subject under discussion, but also because they are the only bilateral arms-control negotiations to have survived the post-Afghanistan freeze in U.S.-Soviet relations. As such, they provide a useful channel -- though not the only one -- for communication between the two superpowers. A disintegration of the talks would make it all the harder to eventually reestablish broader arms-control efforts.

The government is reportedly still waiting for a Soviet response to its questions about the anthrax incident. The story has disappeared from the front pages, and perhaps the Soviet Union is hoping that it will be forgotten in the press of other events. Or perhaps the U.S. government would just as soon have it be forgotten. But finding the truth about possible Soviet use of biological and chemical weapons is still vital. It is important for the survival of the biological warfare convention and of the chemical warfare talks.It may tell us a great deal about Soviet intentions and respect for international obligations. And, by revealing whether the timing of the anthrax announcement was accidental, it may tell us something important about the prospects for other arms-control negotiations.