Edition: U.S. / Global


By JOHN H. CUSHMAN Jr., Special to the New York Times
Published: May 4, 1988

American intelligence agencies suspect as many as 10 nations of developing biological weapons, Reagan Administration officials said today. Aside from the Soviet Union, the officials refused to name the countries, saying the information was secret.

Administration officials made the assertions at a Congressional hearing during which Government witnesses defended the Pentagon's program to develop defenses against biological weapons. The program includes a plan to build a biological laboratory in Utah.

The testimony was the first time that Government officials asserted publicly that so many countries might be developing weapons from viruses, bacteria or toxins produced by biological organisms. Among the nations listed by the Administration were Middle Eastern countries and nations accused by the Reagan Administration of promoting terrorism. 'Yellow Rain' Controversy

The Administration has accused the Soviet Union of developing biological weapons and of using at least one type, ''yellow rain,'' in Afghanistan and, with the complicity of Vietnam, in Southeast Asia. The Administration's accusations on yellow rain were discredited by scientists who said the evidence cited by the Government turned out to be bee droppings and other natural substances.

The Administration offered no proof today to support its assertions that other countries were developing biological arms.

Dr. Thomas Welch, the Pentagon official supervising work on chemical and biological warfare, displayed a chart at the hearing today showing that the number of nations ''having or suspected of having'' programs in offensive biological warfare grew from 4 in 1972 to 10 in 1988.

During the same period, Dr. Welch said, the number of nations with programs in offensive chemical warfare grew from 7 to 20. Unlike biological weapons, chemical weapons, including mustard gas and nerve gas, are not developed from living organisms. The United States and the Soviet Union produce and stockpile offensive chemical weapons. Much Research Is Done

Many nations do research into defending against chemical and biological warfare. The research includes developing vaccines against biological weapons and making protective devices and detection equipment to combat both kinds of weapons.

Dr. Welch, a Deputy Assistant Secretary of Defense, testified before a joint meeting of three Congressional subcommittees that are looking into an Army plan to build a laboratory in Utah for developing defenses against biological weapons. The subcommittees belong to the House Armed Services, Foreign Affairs and Interior committees.

The Utah laboratory, at the Dugway Proving Grounds, faces substantial local opposition. It is a small part of the military's growing program of biological-weapons research. The Reagan Administration has spent more than $300 million on the program in the last seven years. Justification Sought

Dr. Welch, like other Administration witnesses, was asked by members of the three subcommittees to justify the research program by offering unclassified information about the threat of biological weapons. The United States signed the international Biological Weapons Convention of 1972. The Convention prohibits the development or possession of biological agents for military uses other than research into vaccines, detectors and protective hardware.

Dr. Welch urged the lawmakers to attend a classified briefing by intelligence agencies. In his testimony and in subsequent telephone interviews, he provided some details about the nations that are thought to be working on biological weapons.

''Some of the people on the biological list are signatories to the Biological Weapons Convention,'' he said at the hearing. ''Some are in the Middle East. Some are not friendly to the United States, and we have some real concerns about it.''

In subsequent interviews, he said that more than half of the nations on the list signed the biological weapons agreement and that some of those were listed by the State Department as supporters of international terrorism. No Nations Named

After checking secrecy guidelines, Dr. Welch said he could not say whether American allies were on the list or whether Israel was one of the Middle Eastern nations on the list. The nations listed by the State Department as supporting terrorism include Libya, Iran, Cuba, Southern Yemen, Syria and North Korea.

Dr. Welch said the nations suspected of developing biological weapons had worked mainly with organisms against which the United States has some form of defense. The countries are not suspected of using genetic engineering or biotechnology to develop novel organisms as weapons.

Dr. Welch did not specify whether the agents under investigation were toxins, such as the organic mycotoxin known as yellow rain, or other forms of agents, such as the bacteria that cause anthrax.

The Pentagon's research program, according to public documents, has centered on developing vaccines and other medical defenses against a variety of bacteria and viruses that might be used in weapons.