How Do Scientists Determine the Long-Term Risks from Radiation?

The Manhattan Project: A New and Secret World of Human Experimentation

Plucked from campuses around the country, medical researchers came face to face with the need to understand and control the effect upon the thousands of people, doctors included, of radioactive materials being produced in previously unimaginable quantities.

In November 1942 General Groves, through the intermediation of an Eastman Kodak official, paid a call on University of Rochester radiologist Stafford Warren. Rochester, like MIT and Berkeley, was another locale where radiation research had brought together physicists and physicians. "They wanted to know what I was doing in radiation. So I discussed the cancer work and some of the other things," Warren told an interviewer in the 1960s. Then "[w]e got upstairs and they looked in the closet and they closed the transom and they looked out the window. . . . Then they closed and locked the door and said, 'Sit down.'"[22]

Soon thereafter, Dr. Warren was made a colonel in the U.S. Army and the medical director of the Manhattan Project. As his deputy, Warren called on Dr. Hymer Friedell, a radiologist who had worked with Dr. Stone in California. Dr. Stone himself had meanwhile moved to the University of Chicago, where he would play a key role in Manhattan Project-related medical research.

Initially, researchers knew little or nothing about the health effects of the basic bomb components, uranium, plutonium, and polonium. [23] But, as a secret history written in 1946 stated, they knew the tale of the radium dial painters:

The memory of this tragedy was very vivid in the minds of people, and the thoughts of potential dangers of working in areas where radiation hazards existed were intensified because the deleterious effects of radiation could not be seen or felt and the results of over-exposure might not become apparent for long periods after such exposure. [24]

The need for secrecy, Stafford Warren later recalled, compounded the urgency of understanding and controlling risk. Word of death or toxic hazard could leak out to the surrounding community and blow the project's cover. [25]

The need to protect the Manhattan Project workers soon gave rise to a new discipline, called health physics, which sought to understand radiation effects and monitor and protect nuclear worker health and safety. The Project was soon inundated with data from radiation-detection instruments, blood and urine samples, and physical exams. The "clinical study of the personnel," Robert Stone wrote in 1943, "is one vast experiment. Never before has so large a collection of individuals been exposed to so much radiation." [26] Along with these data-gathering efforts came ethical issues.

Would disclosure of potential or actual harm to the workers, much less the public, impair the program? For example, a July 1945 Manhattan Project memo discussed whether to inform a worker that her case of nephritis (a kidney disease) may have been due to her work on the Project. The issue was of special import because, the memo indicated, the illness might well be a precursor of more cases. The worker, the memo explained, "is unaware of her condition which now shows up on routine physical check and urinalysis." [27]

As this memo showed, there was an urgent need for decisions on how to protect the workers, while at the same time safeguard the security of the project: "The employees must necessarily be rotated out, and not permitted to resume further exposure. In frequent instances no other type of employment is available. Claims and litigation will necessarily flow from the circumstances outlined." There were also, the memo concluded, "Ethical considerations":

The feelings of the medical officers are keenly appreciated. Are they in accordance with their canons of ethics to be permitted to advise the patient of his true condition, its cause, effect, and probable prognosis? If not on ethical grounds, are they to be permitted to fulfill their moral obligations to the individual employees in so advising him? If not on moral grounds, are those civilian medical doctors employed here bound to make full disclosure to patients under penalty of liability for malpractice or proceeding for revocation of license for their failure to do so? [28]

It is not clear what was decided in this case. However, the potential conflict between the government doctors' duty to those working on government projects and the same doctors' obligations to the government would not disappear. Following the war, as we see in chapter 12, this conflict would be sharply posed as medical researchers studied miners at work producing uranium for the nation's nuclear weapons.

Another basic question was the extent to which human beings could or should be studied to obtain the data needed to protect them. The radium dial painter data served as a baseline to determine how the effects of exposures in the body could be measured. But this left the question of whether plutonium, uranium, and polonium behaved more or less like radium. Research was needed to understand how these elements worked in the body and to establish safety levels. A large number of animal studies were conducted at laboratories in Chicago, Berkeley, Rochester, and elsewhere; but the relevance of the data to humans remained in doubt.

The Manhattan Project contracted with the University of Rochester to receive the data on physical exams and other tests from Project sites and to prepare statistical analyses. While boxes of these raw data have been retrieved, it is not clear what use was made of them.[29] Accidents, while remarkably few and far between, became a key source of the data used in constructing an understanding of radiation risk. But accidents were not predictable, and their occurrence only enhanced the immediacy of the need to gain better data.

In 1944, the Manhattan Project medical team, under Stafford Warren and with the evident concurrence of Robert Oppenheimer, made plans to inject polonium, plutonium, uranium, and possibly other radioactive elements into human beings. As discussed in chapter 5, the researchers turned to patients, not workers, as the source of experimental data needed to protect workers. By the time the program was abandoned by the government, experimentation with plutonium had taken place in hospitals at the Universities of California, Chicago, and Rochester, and at the Army hospital in Oak Ridge, and further experimentation with polonium and uranium had taken place at Rochester.

The surviving documentation provides little indication that the medical officials and researchers who planned this program considered the ethical implications of using patients for a purpose that no one claimed would benefit them, under circumstances where the existence of the substances injected was a wartime secret. Following the war, however, the ethical questions raised by these experiments would be revisited in debates that themselves were long kept secret.

In addition to experimentation with internally administered radioisotopes, external radiation was administered in human experiments directed by Dr. Stone at Chicago and San Francisco and by others at Memorial Hospital in New York City. Once again, the primary subjects were patients, although some healthy subjects were also involved. In these cases, the researchers may have felt that the treatment was of therapeutic value to the patients. But, in addition to the question of whether the patients were informed of the government's interest, this research raised the question of whether the government's interest affected the patients' treatment. As discussed in chapter 8, these questions would recur when, beginning in 1951, and for two decades thereafter, the Defense Department would fund the collection of data from irradiated patients.

Ensuring safety required more, however, than simply studying how radioactive substances moved through and affected the human body. It also involved studying how these substances moved through the environment. While undetectable to the human senses, radiation in the environment is easily measurable by instruments. When General Groves chose Hanford, on the Columbia River in Washington state, as a site for the plutonium production facility, a secret research program was mounted to understand the fate of radioactive pollution in the water, the air, and wildlife.[30]

Outdoor research was at times improvisational. Years after the fact, Stafford Warren would recall how Manhattan Project researchers had deliberately "contaminated the alfalfa field" next to the University of Rochester medical school with radiosodium, to determine the shielding requirements for radiation-measuring equipment. Warren's associate Dr. Harold Hodge recalled that a shipment of radiosodium was received by plane from Robley Evans at MIT, mixed with water in a barrel, and poured into garden sprinklers:

We walked along and sprinkled the driveway. This was after dark. . . . The next thing, we went out and sprayed a considerable part of the field. . . . It was sprayed and then after a while sprayed again, so there was a second and third application. We were all in rubber, so we didn't get wet with the stuff . . . then Staff [Warren] said that one of the things we needed was to see what would be the effect on the inside of a wooden building. So we took the end of the parking garage, and we sprinkled that up about as high as our shoulders, and somebody went inside and made measurements, and we sprinkled it again. Then we wanted to know about the inside of a brick building, and so we sprinkled the side of the animal house. . . . I had no idea what the readings were. . . I hadn't the foggiest idea of what we were doing, except that obviously it was something radioactive.[31]

Outdoor releases would put at risk unsuspecting citizens, even communities, as well as workers. There were no clear policies and no history of practice to guide how these releases should be conducted. As we explore in chapter 11, this would be worked out by experts and officials in secret, on behalf of the workers and citizens who might be affected.