U.S. government researchers conducted radiation tests on stillborn babies in Chicago during the 1950s, the Department of Energy reported yesterday, in the latest revelation about the wide-scale use of humans in Cold War experiments. In the Chicago tests, scientists cremated 44 newly deceased infants and measured the amount of strontium 90, a radioactive substance, in the remains. Parents were probably not notified or asked permission for the use of their children in the experiments, according to DOE officials familiar with the case. The tests were part of Project Sunshine, a massive study conducted by the Atomic Energy Commission (AEC), a forerunner of DOE, to determine the long-term effects of nuclear radiation fallout on humans. Strontium 90 is among the radioactive particles that typically linger in the body following nuclear weapons tests.

The release of long-classified information about the Chicago Baby Project -- following recent reports about the use of mentally retarded teenagers, ethnic minorities and other disadvantaged groups in radiation tests -- raises new questions about what ethical standards the federal government used in its conduct of Cold War research. DOE officials released documents about the baby tests as part of its mission to inform the American public about the extent that federal researchers involved humans in radiation experiments between the early 1940s and the 1970s. After Energy Secretary Hazel R. O'Leary expressed outrage about the radiation experiments earlier this year, President Clinton appointed an interagency committee to investigate the tests and determine whether the victims should be compensated. Congress is conducting hearings about the use of humans in radiation tests; the House Veterans' Affairs Committee will conduct a session on the subject Wednesday. Although some studies on Project Sunshine were published in the 1950s, most of the details about the Chicago Baby Project were contained in secret government documents that were declassified only last month. Researchers at the Los Alamos laboratory, a DOE facility in New Mexico, found the documents in their files earlier this year. The project was led by Willard Libby, a University of Chicago scientist and senior AEC official who is now dead. Researchers gathered data on the babies "to determine how much fallout humans could bear," said Steve Gallson, a DOE radiation specialist. The experiment "was probably also useful in deciding what the health effects were of the (nuclear weapons) tests being made at the time," he said. The researchers used babies because they provided the best measure of the amount of radiation in the body that was due to fallout rather than from ingesting food or from other sources, according to scientists familiar with the study. All of the babies were stillborn in the early to mid 1950s, according to the documents. None of them died as a result of radiation treatments, DOE specialists said. Gallson acknowledged that some key aspects of the study are not known, such as how the researchers obtained the babies, how much the parents knew about the experiments, and what happened to the remains after the tests were completed. "We are still trying to find out a lot of things about the tests," he said. Don Peterson, a retired Los Alamos researcher familiar with the tests, defended them in an interview yesterday. "There was probably no other way for science to obtain this kind of information at the time," he said. "The use of rats or other animals would not obtain the same results." "This was a case of children who were no longer beneficial to the population being able to provide information that was enormously important for the rest of the world's children," he said. Aside from the stillborn babies, Project Sunshine researchers probed the level of radioactive isotopes left in cheese, milk, animal bones and other substances as a result of the nuclear weapons tests. In the end, they found that the residual effect of the fallout was not extensive in most humans.