Experts consider the 1972 treaty banning development and use of biological weapons to be one of the strongest arms control measures ever concluded. But some of them now are concerned that the substance and the spirit of the Biological and Toxin Weapons Convention - which comes up for review next year - needs to be defended.
They note that the treaty lacks adequate provision for verifying that the ban on development is being observed. Also, they feel uneasy that some recent public discussion of the subject in the United States has suggested that biological weapons might be a legitimate part of the national arsenal, especially if they act as a deterrent to the use of such weapons by other nations.
These concerns were presented in detail at a symposium and press conference held Saturday during the annual meeting of the American Association for the Advancement of Science.
The speakers seemed united in insisting that there is no genuine military use for biological weapons and that there would be great danger to all nations if a biological arms race were begun.
Jonathan King, a microbiologist at the Massachusetts Institute of Technology, explained that biological weapons, being living organisms, are essentially unpredictable in their effects and are uncontrollable. This, he said, renders them useless as military weapons. They could only be weapons of mass destruction. And there is danger during development and testing of such weapons that they could seriously harm crops, farm animals, or even people in the nation doing the development, he added.
Dr. King said the essential points to be considered by anyone toying with the notion of trying to develop such weapons are that they cannot be narrowly targeted and that there is no defense against them. Because of the inherent variability of organisms, their action can't be restricted to a single crop or military target.
Likewise, the variability and wide range of possible ''weapon'' organisms means that no nation could hope to immunize its population or agriculture against attack, he said.
''The combination of increased international tensions and technological advances in biological technology have led to pressure for the development of BW (biological warefare) capacity by the Department of Defense,'' King noted.
But, he warned, ''the development of a biological arms race would pose a grave danger not only to our national security but to the security of the entire species.''
He further warned that steps to develop supposedly defensive biological weapons would be ''indistinguishable'' from development of offensive weapons. Thus any attempt to develop a deterrent could also trigger an arms race and ''should be prohibited,'' he said.
Robert Mikulak of the US Arms Control and Disarmament Agency agreed, noting that even the suspicion that such development might be taking place clandestinely could spark such a race.
Thus, he said, there is an urgent need to strengthen the Biological and Toxin Weapons Convention to provide for tighter verification that such development is not taking place.
Calling the treaty a strong and ''true disarmament'' measure, Mr. Mikulak noted that it was negotiated after the US had unilaterally renounced biological weapons.
''The judgment was that biological weapons had little military value,'' he said. But at the same time, the need for solid verification that the treaty was not being secretly violated was initially recognized only by Sweden, which has been working to tighten treaty provisions.
Now, Mikulak said, it is obvious that credible verification is needed if only to allay suspicions of violations. Such suspicions have arisen within the US partly because some Soviet microbiological work is carried out in secret under military auspices.
If left unchecked, such suspicions - whether concerning the USSR, the US, or any other country - ''can not only undermine the Biological and Toxin Weapons Convention, but also efforts at arms control in other areas,'' Mikulak explained. He added that the US, following Sweden's lead, hopes soon to start informal talks, with a view toward strengthening the verification procedures at next year's review conference.
Meanwhile, several panelists emphasized that one of the best ways to help ensure against biological weapons development is for all recombinant DNA genetic engineering research to be conducted in the open in all countries.
''There is no justification for classified military research on recombinant DNA,'' Mikulak said.
Thomas R. Dashiell from the US Department of Defense pointed out that all such research in his agency already is unclassified and open to public inspection.
Asked about secret industrial research in the US, Mikulak said that given verification provisions in the treaty, even that could be opened up to authorized inspectors, should there be any suspicion of clandestine weapons-related work.