Personnel working at the American embassy in Moscow between 1953 and 1976 suffered no apparent ill effect from the Soviet Union's microwave bombardment of the embassy during those 23 years.

That was the conclusion of the Johns Hopkins University School of Public Health, where more than 100 people spent more than two years in an exhaustive study of the health of the more than 2,000 Americans who worked at the U.S. embassy in Moscow from 1953 to 1976 when the Soviet secret police beamed microwaves at the building to tap telephones and interfere with U.S. telephone and cable traffic.

"With very few exceptions, there was no difference in the health of these people," Johns Hopkins' Dr. Abraham Lilienfield, who directed the study at the request of the State Department, told a news conference yesterday. "There is no convincing evidence to implicate the exposure of these people to microwave radiation and the onset of any adverse health effects."

There was no extraordinary incidence of cancer, brain disorders or loss of vision in any of the embassy personnel scrutinized in the Johns Hopkins study. These were the three types of disease looked for in the study, since experiments with animals suggested in the past that microwave beams can cause malignancies, neurological disorders and cataracts in the eyes of animals given heavy doses of microwaves.

The Johns Hopkins group attributed the rise in white blood cell count and the complaints of headaches, loss of memory and fitful sleep among embassy personnel two years ago to a normal rise in infectious disease and to the publicity given the microwave bombardment at the time.

"There is a high incidence of bacterial infection in the Soviet Union, which was the case of the high white-cell count," said Dr. James Tonascia, who helped to direct the Johns Hopkins study. "At that same time, the Moscow group showed a high degree of nervousness, anxiety, loss of memory and sleep which we could in no way tie in with the effects of microwave radiation. "Maybe it was the result of the publicity given the microwave incident or the stress of living in Moscow.

Nonetheless, the Johns Hopkins study team recommended that State Department physicians follow personnel who served in the embassy in Moscow, especially those who worked there in 1975 and 1976 when the Soviets increased the intensity of the microwave beam directed at the upper three floors of the 10-story embassy building.

"I would recommend this recent group of about 400 people be followed and examined every two years for the next 10 years," Dr. Lilienfeld said. "It's too recent a period for ill effects to develop to the point where they might be noticed right now."

The Soviets began beaming microwaves at the upper three floors along the west facade of the embassy building in 1953. The beam bombarded the upper three floors nine hours a day until 1975, when the beam was redirected, intensified and prolonged.

From May 30, 1975, to February 1976, the beam was redirected to the south and east facades of the building and was increased seven times in intensity and extended to 18 hours a day. At this, the State Department filed a formal protest and installed aluminium screens across the windows of the upper three floors, which kept out 90 percent of the beam.

The State Department has never explained why it thought the Soviets bombarded the U.S. embassy with microwaves, but it would have to be for surveillance of some kind - to tap long-distance telephone calls or to interfere with telephone and cable traffic that are relayed by microwave.

The reason the microwave beam was directed at the upper floors of the building is that is where key embassy personnel have their offices. The U.S. ambassador, his key aides, military attaches and Central Intelligence Agency officials assigned to the embassy all work on the top floors.

Lilienfeld said the Johns Hopkins study was the most exhaustive statistical study ever carried out on the effects of microwave radiation on humans. He said it involved the search of more than 150,000 records of State Department personnel, thousands of questionnaries and telephone calls to people who had moved four and five times around the world.

"Our hardest job was finding people who had long left Moscow," Lilienfeld said. "Believe it or not, nobody at State keeps records of people who have been there."

In its study of embassy personnel, the Johns Hookins group discovered that the men in the embassy suffered an incidence of cancer half what their counterpart age brackets suffered in the United States. The women fared less well, but their cancer rate still was less than their counterparts in the United States.

"We think this is due to what's called the 'healthy worker effect.'" Lilienfeld said. "By that I mean, the State Department only sends to places like Moscow people who pass pretty stiff medical exams."

The way the Johns Hopkins team set up the study was to compare the health of an estimated 2,000 Moscow embassy personnel with a similar sized group of people who had worked in U.S. embassies in Leningrad, Budapest, Belgrade, Zabreg, Prague, Bucharest and Warsaw, all Eastern European cities.

"We wanted to compare the health effects," Lilenfeld said, "in places where social and living conditions were similar to those in Moscow."

Lilenfeld said the microwave bombardment was confined to the embassy in Moscow. He said there was no evidence of any microwave beaming in Leningrad or in any of the cities of Eastern Europe where the United States has embassies.