Officials involved in U.S. atomic bomb tests feared in 1965 that disclosure of a secret study linking leukemia to radioactive fallout from the bombs could jeopardize further testing and result in costly damage claims, according to documents obtained by The Washington Post.

That study, as well as a proposal to examine thyroid cancer rates in Utah, touched off a series of top-level meetings within the old Atomic Energy Commission over how to influence or change the two studies.

The documents also indicate that the Public Health Service, that nation's top health agency, which conducted the studies, joined AEC in reassuring the public about any possible danger from Fallout.

Disclosure of the new documents, the result of Freedom of Information requests by The Washington Post, comes on the eve of joint congressional hearings into the possible health damgages caused by scores of above-ground nuclear explosions at the Nevada Test Site from 1951 to 1962.

Two previous inquiries on fallout and health were held by the Joint Committee on Atomic Energy in 1959 and 1963.But next week's hearings in Salt Lake City by health and government operations subcommittees will be the first on the subject conducted by congressional committees not also responsible for promoting nuclear development.

In response to The Post's request, the Department of Health, Education and Welfare has made public nearly 40,000 pages of files dealing with radiation, some 35,000 of them released last week. Other documents were obtained from the Department of Energy, a successor to the AEC.

Among the documents were ones showing that:

A 1959 study found higher levels of the radioactive isotope strontium-90 in the bones of younger children in the fallout zone. Coincidentally, a Utah state epidemiologist found this year that children living in the zone during the weapons testing had 2.5 times as much leukemia as children before and after the testing program.

A White House panel of radiation officials concluded in 1962 that nuclear testing had increased the risks of adverse health effects. Despite that, the government has rigidly maintained testing caused no harm.

A 1959-60 spurt in leukemia in the southwestern Utah counties of Washington and Iron was first detected by a health investigator in 1961, and fallout was immediately suspected.

That observation, by Edward S. Weiss, eventually led to the 1965 finding that the two counties experienced nine more leukemia cases than the 19 statistically expected. Weiss' study, disclosed in January after 13 years by The Washington Post, was essentially completed in July 1965, when Weiss submitted it for publication in a health service journal.

By Sept. 1, of that year, a copy of Weiss' leukemia study had been sent to the AEC, as had the Public Health Service's proposal to test schoolchildren in southwest Utah for thyroid abnormalities.

The AEC discussed the two studies that morning. The same day, a White House science adviser called the Health Service toask, "what would be the federal government's liability" for any health problems found?

By five that afternoon, a joint AEC-Health Service-White House meeting was set for the next day - with three HEW lawyers present, an extraordinary sign of the legal problems the studies could cause.

At the meeting, AEC representatives critcized the leukemia studies and the proposed thyroid study. It was agreed they would submit suggestions for changes.

A week later, the AEC was ready with a proposed letter to the surgeon general, the head of the Public Health Service. Dwight A. Ink, then assistant general manager of the AEC, told his commissioners:

"Although we do not oppose developing further data in these areas [leukemia and thyroid abnormalities] performance of the . . . studies will pose potential problems to the commission and jeopardizing the programs at the Nevada Test Site."

The next day, Sept. 10, Ink sent to the surgeon general a critique containing criticisms of the study's scientific basis which were made public in January with the Weiss report. The letter did not, however, make any reference to the AEC's concerns about damage suits, adverse publicity or its effect on the testing program.

Meanwhile, the Public Health Service was gearing up to announce the thyroid study and to disclose the leukemia study. Weiss' study was formally prepared and dated Sept. 14. Two days later, the thyroid study was announced, but there was no mention of the leukemia findings.

One Health Service document suggests that the service itself may have even suppressed the study temporarily to avoid excessive press coverage of the thyroid study. "All of this interest," an official wrote of the congressional and press concern for fallout studies, "will be intensified if publication of the leukemia portion of the study occurs before the [thyroid] project begins."

Earlier, the Health Service had decided to minimize any publicity of the thyroid study.

The result was that the Weiss study was not released and in 1966 was still under review and revision. It was never released.

The thyroid study, however, which eventually exonerated the nuclear tests, was published, despite acknowledgements that there were severe limitations to it.

"There are some serious problems with the thyroid study," says Dr. Joseph L. Lyon, the Utah epidemiologist who recently documented the increase in leukemia among testing-area children. And Weiss' leukemia study, said Lyon, had detected what Lyon would prove 13 years later.