 Section 6, a final report of the Advisory Committee on Human Radiation Experiments. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Jennifer Painter. Final report of the Advisory Committee on Human Radiation Experiments. Introduction Part 2. The Manhattan Project, a new and secret world of human experimentation. In August 1942, the Manhattan Engineer District was created by the government to meet the goal of producing an atomic weapon under the pressure of ongoing global war. Its central mission became known as the Manhattan Project. Under the direction of Brigadier General Leslie Groves of the Army Corps of Engineers, who recently had supervised the construction of the Pentagon, secret atomic energy communities were created almost overnight in Oak Ridge, Tennessee, at Los Alamos, New Mexico, and in Hanford, Washington, to house the workers and gigantic new machinery needed to produce the bomb. The weapon itself would be built at the Los Alamos Laboratory under the direction of physicist J. Robert Oppenheimer. Plugged 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 we got upstairs and they looked in the closet and they closed the transom and they looked out of the window. Then they closed and locked the door and said, sit down. 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. Heimer Friedel, 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. 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 overexposure might not become apparent for long periods after such exposure. The need for secrecy, Stafford Warren later recalled, compounded the urgency of understanding and controlling risk. Words of death or toxic hazard could leak out to the surrounding community and blow the project's cover. 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 larger collection of individuals been exposed to so much radiation. 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. 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 fulfil 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 licence for their failure to do so? It is not clear what was decided in this case. However, the potential conflict between the government's doctor's duty to those working on government projects and the same doctor's 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 minors 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. 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 patient's 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. 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 Stafford 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. 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, the Atomic Energy Commission and Post-War Biomedical Radiation Research. On August 6, 1945, when the atomic bomb was dropped on Hiroshima, the most sensitive of secrets became a symbol for the ages. A week later, the bomb was the subject of a government report that revealed to the public the uses of plutonium and uranium. Immediately, debate began over the future of atomic energy. Could it be controlled at the international level? Should it remain entirely under control of the military? What role would industry have in developing its potential? Although American policymakers failed to establish international control of the bomb, they succeeded in creating a national agency with responsibility for the domestic control of atomic energy. The most divisive question in the creation of the new agency that would hold sway over the atom was the role of the military. Following congressional hearings, the Atomic Energy Commission established by the 1946 McMahon Act to be headed by five civilian commissioners. President Truman appointed David Lillianthor, former head of the Tennessee Valley Authority, as the first chairman of the AEC, which took over responsibilities of the Manhattan Engineer District in January 1947. Also in 1947, under the National Security Act, the armed services were put under the authority of the newly created National Military Establishment, NME, to be headed by the Secretary of Defense. In 1949, the National Security Act was amended and the NME was transformed into an executive department, the Department of Defense. The Armed Forces Special Weapons Project, which would coordinate the Defense Department's responsibilities in the area of nuclear weapons, became the military heir to the Manhattan Engineer District. The Military Liaison Committee was also established as an intermediary between the Atomic Energy Commission and the Defense Department. It was also to help set military requirements for the number and type of nuclear weapons needed by the armed services. Even before the AEC officially assumed responsibility for the bomb from the Manhattan Project, the Interim Medical Advisory Committee, chaired by former Manhattan Project medical director Stafford Warren, began meeting to map out an ambitious post-war biomedical research program. Former Manhattan Project contractors proposed to resume the research that had been interrupted by the war and to continue wartime radiation effects studies upon human subjects. In May 1947, Lillian Thorle commissioned a blue ribbon panel, the Medical Board of Review, that reported the following month on the agency's biomedical program. In strongly recommending a broad research and training program, the Board found the need for research, both urgent and extensive. The need was urgent because of the extraordinary danger of exposing living creatures to radioactivity. It is urgent because effective defensive measures in the military sense against radiant energy are not yet known. The Board, pointing to the AEC's absolute monopoly of new and important tools for research and important knowledge, noted the commensurate responsibilities both to employees and others who could suffer from its negligence or ignorance and to the scientific world with which it was obliged to share its acquisitions whenever security considerations permit. In the fall of 1947, as recommended by the Medical Board of Review, the AEC created a Division of Biology and Medicine, DBM, to coordinate biomedical research involving atomic energy and an Advisory Committee for Biology and Medicine, ACBM, which reported directly to the AEC's chairman. Not surprisingly, the DBM and ACBM became gathering places for the luminaries of radiation science. The ACBM was headed by a Rockefeller Foundation official, Dr. Alan Gregg. It settled on Dr. Shields Warren, a Harvard-trained pathologist to serve as the first chief of the DBM. Warren, as we shall see, would play a central role in developments related to radiation research and human experimentation. In the 1930s, focusing on cancer research and influenced by the work of Heather Z and the pioneering radioisotope work being done in Berkeley and Boston, Warren turned to the question of the effects of radiation on animals and the treatment of acute leukemia, the most hopeless of tumors at that time. As the war neared, Warren enlisted in the Naval Reserve. He continued medical work for the Navy, turning down an invitation to join Stafford Warren, no relation, on a project that he couldn't tell me anything about, the Manhattan Project. While most of the AEC's budget would be devoted to highly secret weapons development and related activities, the Biomedical Research Program represented the commission's proud public face. Even before the AEC opened its doors, Manhattan Project officials and experts had laid the groundwork for a bold program to encourage the use of radioisotopes for scientific research, especially in medicine. This program was first presented to the broad public in a September 1946 article in the New York Times magazine. The article began dramatically by describing the use of radioactive salt to measure circulation in a crushed leg so that a decision on whether to amputate below or above the knee could be made. By November 1946, the isotope distribution program was well underway, with more than 200 requests approved, about half of which were designated for human uses. From the beginning, the AEC's isotope division at Oak Ridge had in its program director, Paul Abersold, a veritable Johnny Appleseed for radio elements. In presentations before the public and to the researchers, Abersold, dubbed Mr. Isotope, touted the simplicity and low cost with which scientists would be provided with radioisotopes. The materials and services are made available with a minimum of red tape and under conditions which encourage their use. At an international cancer conference in St. Louis in 1947, the AEC announced that it would make radioisotopes available without cost for cancer research and experimental cancer treatment. This, Shields Warren later recalled, had a tremendous effect and led to a revolution in the type of work done in this field. To AEC administrators, Abersold emphasized the benefits to the AEC's public image. Much of the commission's success is judged by the public and scientists on its willingness to carry out a wide and liberal policy on the distribution of materials, information and services. He wrote in a memo to the AEC's general manager. The AEC biomedical program as a whole also provided for funding of cancer research centres, research equipment and numerous other research projects. Here too were advances that would save many lives. Before the war, radiotherapy had reached a plateau limited by the cost of radium and the inability of the machines of the time to focus radiation precisely on tumours to the exclusion of surrounding healthy tissue. AEC facilities inherited from the Manhattan Project could produce radioactive cobalt, a cheaper substitute for radium. As well, the AEC's tele-therapy program funded the development of new equipment capable of producing precisely focused high energy beams. The AEC's highly publicised peacetime medical program was not immune to the pressures of the Cold War political climate. Even the lives of young researchers in the AEC fellowship program conducting non-classified research were subject to Federal Bureau of Investigation review despite protests from commissioned members. Congressional mandated Cold War requirements such as loyalty oaths and non-communist affidavits Chairman Lillian Thord declared would have a chilling effect on scientific discussion and could damage the AEC's ability to recruit a new generation of scientists. The reach of the law the advisory committee for biology and medicine agreed was like a blighting hand for thoughtful men now know how political domination can distort free enquiry into a malignant servant of expediency and authoritarian abstraction. Nonetheless, the AEC accepted the congressional conditions for its fellowship program and determined to seek the program's expansion. The AEC's direct promotional efforts were multiplied by the success of Abbasol and his colleagues in carrying the message to other government agencies as well as to industry and private researchers. This success led in turn to new programs. In August 1947, General Groves urged Major General Paul Hawley the director of the medical programs of the Veterans Administration to address medical problems related to the military's use of atomic energy. Soon thereafter, Hawley appointed an advisory committee manned by Stafford Warren and other medical researchers. The advisors recommended that the VA create both a publicised program to promote the use of radioisotopes in research and a confidential program to deal with potential liability claims from veterans exposed to radiation hazards. The publicised program soon mushroomed with Stafford Warren, Shields Warren and Heimer Friedl among the key advisors. By 1974, according to VA reports, more than 2,000 human radiation experiments would be performed at VA facilities, many of which would work in tandem with neighbouring medical schools such as the relationship between the UCLA medical school, where Stafford Warren was now dean, and the Wadsworth West Los Angeles VA hospital. While the AEC's weapon-related work would continue to be cloaked in secrecy, the isotope program was used by researchers in all corners of the land to achieve new scientific understanding and help create new diagnostic and therapeutic tools. It was, however, only a small part of an enormous institution. By 1951, the AEC would employ 60,000 people, all but 5,000 through contractors. Its land would encompass 2,800 square miles, an area equal to Rhode Island and Delaware confined. In addition to research centres throughout the United States, its operations extended from the ore fields of the Belgian Congo and the Arctic regions of Canada to the weapons-proving ground at NWTAC Atong in the Pacific, and the medical projects studying the aftereffects of atomic bombing in Japan. The isotope division, however, would employ only about 50 people, and when reactor production time was accounted for, occupy only a fraction of its budget and resources. End of introduction, Part 2. Section 7 of the final report of the Advisory Committee on Human Radiation Experiments. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Stephen Sutliff. Final report of the Advisory Committee on Human Radiation Experiments. Introduction, Part 3. The Transformation in Government Sponsored Research. The AEC's decision to proceed with a biomedical research programme was part of an even greater transformation in which government continued and expanded wartime support for research in industry and at universities. Before World War II, biomedical research was a small enterprise in which the federal government played a minor role. During the war, however, large numbers of American biomedical researchers were mobilized by the armed forces. These researchers played an important role in advancing military medicine in a wide range of areas, including blood substitutes, anti-malarial drugs, and, as noted above, developing the infant science of nuclear medicine. As the war was drawing to a close, President Roosevelt asked for advice from his Office of Scientific Research and Development, OSRD, on how to convert the nation's military research effort to a peacetime footing and whether the government should take an activist role in promoting research. The OSRD, under Vannevar Bush, responded in July 1945 after Roosevelt's death with a report called Bush and his colleagues recommended, among other things, the establishment of a National Science Foundation, NSF, to support basic research in all areas, including the biomedical sciences. While the principle that the federal government should fund medical research came to seem self-evident, this was hardly the case at the time. In a personal reminiscence published in 1970, Bush wrote, To support the Congress of these pragmatically inclined United States to establish a strong organization to support fundamental research would seem to be one of the minor miracles. We in this country have supported well those pioneers who have created new gadgetry for our use or our amusement, but we have not had during our formative years the respect for scientific endeavors for scholarship generally to the extent it had been present in Europe. Congress worked Bush's small miracle and passed relevant legislation, but President Harry Truman vetoed the bill. When the bill passed again, however, Bush persuaded Truman to sign it. At the new AEC and elsewhere, a key element of the support for science was the determination to fund extramural research, that is, research outside the agency. Prior to the war, federal support for private researchers was limited. The Manhattan Project was only one of several wartime efforts that drew private researchers into government service and that provided federal funds for those who remained in private research centers. Following the war, as researchers returned to universities, laboratories, and hospitals, the continued federal support of their efforts transformed the relationship between government and science and the dimensions of the scientific effort. During the war, the Committee on Medical Research CMR of the OSRD operated entirely by funding external research. In 1944, Congress empowered the Surgeon General of the Public Health Service to make grants to universities, hospitals, laboratories, and individuals, which provided the legislative basis for the Post-War National Institute of Health NIH extramural program. In 1948, Congress authorized the National Heart Institute to join the Medicaid Old National Cancer Institute and NIH became the National Institutes of Health. By the late 1960s, the annual appropriations of NIH exceeded $1 billion. Research involving medical use of radioisotopes and external radiation was among the newer fields benefiting from the increased funding. As discussed in more detail in Chapter 6, governments of ported radioisotope research has proved profoundly important in the development of techniques for medical diagnosis and treatment. Federal research funding has also continued to be essential to the development of the use of external sources of radiation. For example, the crude images made possible by Rankin's discovery of x-rays have been replaced by higher resolution three-dimensional pictures, such as those produced by computerized tomographic CT scanning and magnetic resonance imaging MRI. Today, the benefits of federally-sponsored medical research are often taken for granted. To many of those in the midst of the post-war planning and advocacy, however, the result was not foreordained. Fortunately, Shields-Warren recalled years later, post-war momentum, kept AEC research budgets on track until, in 1957, the Soviet launch of Sputnik, the first space satellite, jolted the American people into a renewed commitment to the support of scientific research. The aftermath of Hiroshima and Nagasaki, the emergence of the Cold War Radiation Research Bureaucracy. While promoting the beneficial uses of radiation, the government also wished to continue and expand research on its harmful effects. Three days after the destruction of Hiroshima, Robert Stone wrote two letters to Stafford Warren's deputy and Stone's former student, Heimer Friedl. The first expressed hope that the contribution of medical researchers could now be made public so that people would know what they had done during the war. The second letter described Stone's mixed feelings at the success that had been achieved and his fear that the lingering effects of radiation from the bomb had been underestimated. Quote, I could hardly believe my eyes. Stone wrote, When I saw a series of news releases said to be quoting Oppenheimer and giving the impression that there is no radioactive hazard. Apparently all things are relative, unquote. Friedl and other researchers, including Stafford Warren and Shields Warren, soon traveled to Hiroshima and Nagasaki to begin what became an extensive research program on survivors. The data from that project quickly became and still remained the essential source of information on the long-term effects of radiation on populations of human beings. It was not long, however, before there were additional real-life data on the bomb from post-war atomic tests. In 1946, the United States undertook the first peacetime nuclear weapons tests at Bikini Atoll in the Marshall Islands. Operation Crossroads, conducted before journalists and VIPs from around the world, was intended to test the ability of a flotilla of unmanned ships to withstand the blast. Since most of the ships remained afloat, the Navy declared Crossroads a triumph. Behind the scenes, however, Crossroads medical director Stafford Warren expressed horror at the level of contamination on the ships due to the underwater atomic blast. When the ships returned to the West Coast from the Pacific, they were extensively studied to assess the damage and contamination from the atomic bombs. The government created the Naval Radiological Defense Laboratory, NRDL, to study the effects of atomic bombs on ships and to design ways to protect them. Quote Crossroads, unquote, left no doubt that man was faced with a necessity for coping with strange and unprecedented problems for which no solutions were available, unquote. Hiroshima and Nagasaki, it now seemed, were only the beginning, not the end, of human exposure to bomb-produced radiation. As Crossroads confirmed with the lingering problem of contaminated ships, what the bomb did not obliterate, it might still damage by radiation over the course of days or years. It was no longer enough to know about the effects of radioactive materials on American nuclear weapons workers. Now, there was an urgent need to understand the effects on American soldiers, sailors, and even citizens as well. Largely invisible to the public, an ad hoc bureaucracy sprang up to address the medical and radiation research problems of atomic warfare. This bureaucracy brought together former wartime radiation researchers who were joined by the U.S. to advise and participate in the government's growing radiation research program. Other already established groups, such as the AEC's division of biology and medicine and its advisory committee, also had important places in the new network. Beyond considering fallout from the testing of atomic bombs, these groups also looked at how radiation itself might be used as a weapon. Or scientists like J. Robert Oppenheimer had speculated on the possibility that fission products, radioactive materials produced by the bomb or by reactors, could be dispersed in the air and on the ground to kill or incapacitate the enemy. In 1946, the widespread contamination of ships at crossroads by radioactive mist gave dramatic evidence of the potential of so-called Radiological Warfare, or RW. In 1947, the military created a committee of experts to study the problem. The following year, a blue ribbon panel of physicians and physicists looked at the prospects, both offensive and defensive, of what the Pentagon termed rad war. The work of these panels would lead to dozens of intentional releases of radiation into the environment by the Army's Dugway, Utah testing grounds from the late 1940s to the early 1950s. The very fact that the government was engaged in RW tests was a secret. Indeed, the records of the RW program, including, as we shall see in Chapter 11, the debate on what the public should be told about the program, would remain largely secret for almost 50 years. In 1949, a military program to build a nuclear-powered airplane led to a set of proposed human radiation experiments. The NEPA, Nuclear Energy Pulsion of Aircraft program, had its origins in 1946 as a venture that included the Manhattan Project's Oak Ridge site, the military, and private aircraft manufacturers. Robert Stone, as we shall see in Chapter 8, was a leading proponent of experiments involving healthy volunteers, as a key to answering questions about the radiation hazard faced by the crew of the proposed airplane. The NEPA and RW groups considered important but still discreet projects. Where did the big picture discussions take place? The advisory committee have pieced together the records of the Armed Forces Medical Policy Council, the Committee on Medical Sciences, and the joint panel on the medical aspects of atomic warfare. These three Defense Department groups, all chaired by civilian doctors, guided the government on both the broad subject of military-related biomedical research and the new and special problems posed by atomic warfare. If the surviving records are an indication, from its creation in 1949 to its evident demise with the reorganization of the Defense Department in 1953, the joint panel quickly became the hub of atomic warfare-related biomedical research. The joint panel gathered information about relevant research from all corners of the government, provided guidance for defense department programs, and reviewed and coordinated policy in the matter of human experimentation using atomic energy. By charter, the group was to be headed by a civilian. Harvard's Dr. Joseph Albe, a longstanding member of the Boston-based medical research community who had worked with Robly Evans on the study of the radium-dial painters and had also studied lead toxicity served as chair. Those who served with Albe included Heimer Friedle and Louise Hempelman, Oppenheimer's Manhattan Project Medical Aid. Other government participants came from the AEC, the Public Health Service, the National Institutes of Health, the Veterans Administration, and the CIA. The charter provided that the joint panel should collect information on relevant research conducted abroad, which the CIA evidently provided. This bureaucracy provided the venue for secret discussions that linked the arts of healing and war in ways that had little precedent. At one and the same time, for example, doctors counseled the military about the radiation risked troops at the site of atomic bomb tests, advised on the need for research on the psychology of panic at such bomb tests, and debated the need for rules to govern atomic warfare-related experimentation. See Chapter 10. The records of the joint panel show that, during the height of the Cold War, the civilian agencies were part of the mobilization of resources to serve national security interests. For example, Dr. Howard Andrews, trained as a physicist, was the National Institutes of Health's representative to the joint panel, and in the 1950s he worked with the DoD and the AEC in monitoring safety measures and measuring fallout from nuclear tests. In 1950 President Truman ordered federal agencies, including the Public Health Service and NIH, to focus their resources on activities that would benefit national security needs. On paper at least, PHS and NIH policymakers sought to direct resources to questions of radiation injury, civil defense and worker health and safety. For example, a 1952 internal planning memo explained that NIH quote, will not wait for formal requests by the armed services to undertake research which NIH staff knows to be of urgent military and civilian defense significance. Limited selective conversion of research to work directly related to biological warfare, shock, radiation injury, and thermal burns will begin immediately. The fragmentary surviving documentation, however, does not show the extent to which PHS and NIH funded researchers actually redirected their investigations or merely recast the purpose of ongoing work. New ethical questions for medical researchers. As medical researchers became fixtures in the Cold War research bureaucracy, they assumed roles that, if not entirely new, raised ethical questions with which they had rarely dealt before. The surviving records of the period reveal that frank and remarkable discussions took place among military and civilian officers and researchers, all of whom had to balance the benefits of gaining knowledge needed to fight and survive an atomic war with the risks that had to be taken to gain this knowledge. They had to consider, and even debated, whether human radiation experimentation was justified, what kinds of risks entire populations could be exposed to, and what the public could and should be told. Whether to experiment with humans, the debate is joined. Spurred by proposals for human radiation experiments connected with the Nuclear Powered Airplane, NEPA, project, AEC and DoD medical experts in 1949 and 1950 engaged in debate on the need for human experimentation. The transcript of a 1950 meeting among AEC biomedical officials and advisors and military representatives provides unique insight into the mix of moral principles and practical concerns. The participants in the debate included many of the key medical figures in the Manhattan Project on the post-war radiation research bureaucracy. For the Navy, for example, Captain Barron's, the editor of Atomic Medicine, made the point that an atomic bomb might contaminate, but not sink, ships. The Navy would need to know the risk of sending rescue or salvage parties into the contaminated area. There were questions of quote, calculated risk which all of the services are interested in, and not only the services, but probably the civilians as well, unquote. Brigadier General William H. Powell Jr. of the Office of the Air Force Surgeon General added further questions. How does radiation injure tissue? Can equipment protect against the atomic bomb's effects? Is there a way to treat radiation injury? How should mass casualties be handled? These questions were hardly abstract. Operation Crossroads had demonstrated that post-blast contamination of Navy ships was a serious hazard. The use of the atomic bomb as a tactical weapon, declared Brigadier General James Cooney of the AEC's Division of Military Applications, quote, has now gone beyond the realm of possibility and into the realm of probability, unquote. This meant that, quote, we have a responsibility that is tremendous, unquote, Cooney added, quote, if this weapon is used tactically on a corps or division and we have, say, 5,000 troops who have received 100 rinkins of radiation, the commander is going to want from me, is it all right for me to reassemble these men and take them into combat? I don't know the answer to that question, unquote. Commanders needed to know, quote, how much radiation can a man take, unquote. Cooney argued that human experimentation was necessary. He invoked the military's tradition of experimentation with healthy volunteers, dating back to Walter Reed's famous work on yellow fever the turn of the century. Cooney urged that the military seek volunteers within its ranks, quote, both officer and enlisted, unquote, to be exposed to as much as 150 rinkins of whole body radiation. The AEC's Shields Warren took the other side in this debate. Warren raised two basic points in response to Cooney. First, human experimentation was not essential because animal research would be adequate to find the answers. Second, data from human experimentation would likely be scientifically useless, quote, we have, unquote, Warren declared, quote, learned enough from animals and from humans at Hiroshima and Nagasaki to be quite certain that there are extraordinary variables in this picture. There are species variables, genetic variables within species, variations in condition of the individual within that species, unquote. The danger of failing to provide data had to be weighed against the danger of providing data, quote, it might be almost more dangerous or misleading to give an artificial accuracy to an answer that is of necessity, an answer that spreads over a broad range in light of these variables, unquote. There were, moreover, political obstacles to the program Cooney had proposed. Satisfactory answers Warren concluded would require, quote, going to tens of thousands of individuals, unquote. But America was not the Soviet Union, quote, if we were considering things in the Kremlin, undoubtedly it would be practicable. I doubt that it is practicable here, unquote. At the heart of Warren's objections to Cooney's proposal was a concern about employing, quote, human experimentation when it isn't for the good of the individual concerned and when there is no way of solving the problem, unquote. To Cooney's invocation of Walter Reed, Warren responded that in the case of yellow fever humans were needed as subjects because there was no non-human host to the disease. Cooney did not disagree with Warren, quote, that statistically we will prove nothing, unquote. But he pointed out, quote, generals are hard people to deal with. If we had 200 cases whereby we could say that these men did or did not get sick up to 150 Rankin, it would certainly be of great help to us, unquote. Even then, Warren rejoined, the data might not be of great use. I can think in terms of times when even if everybody on a ship was seasick, you would still have to keep the ship operating, unquote. The 1950 debate over NEPA provides clear evidence that mid-century medical experts gave thought before engaging in human experimentation that involved significant risk and was not intended to benefit the subject. On paper, the debate was decided in Shields Warren's favor. Following Warren's and DBM's opposition, Cooney and the military agreed that, quote, human experimentation, unquote, unhealthy volunteers would not be approved. However, even as this policy was declared, the Defense Department, with Warren's apparent acquiescence, proceeded to contract with private hospitals to gather data on sick patients who were being treated with radiation. The government's use of sick patients for research, as we shall see in Chapter 8, raised difficult ethical questions of its own. Whether to put populations at risk, the debate continues. As medical experts debated the issue of whether to put individual human subjects at risk in radiation experiments on behalf of NEPA, they were also engaged in secret discussions about whether to proceed with the testing of nuclear weapons, which might put whole populations at risk. It was also in 1950 that the decision was made to carry out atomic bomb testing at a site in the continental United States. President Truman chose the Nevada desert as location for the test site. Shields Warren's division of biology and medicine was assigned the job of considering the safety of early tests. Like the earlier transcript, an account of a May 1951 meeting at Los Alamos, convened by Warren, provides a window onto the balancing of risks and benefits by medical researchers. The meeting focused on the radiological hazards to populations downwind from underground testing planned at the Nevada test site. Those in attendance realized that the testing could be risky. Quote, I would almost say from the discussion this far unquote Warren summarized quote, that in light of the size and activity of some of these particles, their unpredictability of fallout, the possibility of external beta burns is quite real unquote. Committee members considered the testing a quote, calculated risk unquote for populations downwind, but they thought that the information they could gain made the risk worthwhile. According to the record of the meeting, Warren summarized the view of Dr. Gaiaccino Faila, a Columbia University radiological physicist quote, the time has come when we should take some risk and get some information. We are faced with a war in which atomic weapons will undoubtedly be used, and we have to have some information about these things. If we look for perfect safety we will never make these tests unquote worried about the potential consequences of miscalculation the AEC's Carol Tyler observed quote we have lost a continental site no matter where we put it unquote still Tyler argued quote, if we are going to gamble it might as well be done where it is operationally convenient unquote a proposed deep underground test did not take place and a test evidently considered less risky was substituted ultimately in a summary prepared at the end of the 1951 test series the health division leader of the AEC's Los Alamos laboratory recorded that perhaps only good fortune had averted significant contamination quote, thanks to the kindness of the winds no significant activity was deposited in any populated localities it was certainly shown however unquote, he wrote quote, that significant exposures at considerable distances could be acquired by individuals who actually were in the fallout while it was in progress unquote, the NEPA debate and the advent of nuclear testing confronted biomedical experts with a set of conflicting and even contradictory objectives first they were called upon to offer advice on decisions that might inevitably put people at some risk the risk had to be balanced against the benefit which in most instances was defined as connected with the nation's security in many cases the experts agreed it was better to bear the lesser risk now in order to avoid a greater risk later second these experts were also called upon as in the 1951 Nevada test to provide advice on minimizing risk third as in the Nevada test these same experts saw the tests as opportunities to gather data that might ultimately be used to reduce risk for all whether and what the public should be told about government created radiation risk scientific research had a long and celebrated tradition of open publication in the scientific literature but several factors caused cold war researchers to limit their public disclosures these included preeminently concern with national security which necessarily required secrecy but they also included the concern that the release of research information would undermine needed programs because the public could not understand radiation or because the information would embarrass the government the tension between the publicizing of information and limits on disclosure was a constant theme in cold war research when in June 1947 the medical board of review appointed by David Lienthal reported on the AEC's biomedical program it declared that secrecy in scientific research is quote distasteful and in the long run contrary to the best interests of scientific progress unquote as shown by its organization of the medical isotope program the AEC acted quickly to make sure that the great preponderance of biomedical research done under its auspices would be published in the open literature however recently retrieved documents show that the need for secrecy was also invoked when national security was not endangered at the same time that biomedical officials such as those on the medical board of review spoke openly of the need to limit national security restrictions internally they sometimes sided with those who would restrict information from the public even where release admittedly would not directly endanger national security thus as we shall see in chapter 13 Shields Warren and other AEC medical officials agreed to withhold data on human experiments from the public on the grounds that they would embarrass the government or could be a source of legal liability a further important qualification to what the public could know related to research connected with the atomic bomb including the creation of a worldwide network to gather data on the effects of fallout from nuclear tests in 1949 the AEC undertook project Gabriel a secret effort to study the question of whether the test could threaten the viability of life on earth finally Gabriel led to project sunshine a loose confederation of fallout research projects whose human data gathering efforts as we shall see in chapter 13 operated in the twilight between openness and secrecy finally while documents show that medical experts and officials shared an acute awareness of the importance of public support to the success of cold war programs this awareness was coupled with concern about the American public's ability to understand the risks that had to be born to win the cold war the concern that citizens could not understand radiation risk is illustrated by a recently recovered NEPA transcript in july 1949 the nuclear airplane project gathered radiation experts and psychologists to consider psychological problems connected to radiation hazard to the assembled experts the greatest unknown was not radiation itself but the basis for public fear and misunderstanding of radiation quote I believe quote general cooney proposed quote that the general public is under the opinion that we don't know very much about this condition radiation we know quote he ventured quote just about as much about it as we do about many other diseases that people take for granted even tuberculosis unquote yet so the navy's captain quote there are some peculiar ideas relative to radiation that are related to primitive concepts of hysteria and things in that category there is such a unique element in it for some it begins to border on the mystical unquote a good deal of the public sphere radiation declared berkeley's doctor carl m bowman a NEPA medical advisor quote is essentially the fear of the unknown the dangers have been enormously magnified unquote as doctor bowman and others noted the public's perception was not without reason for quote we have emphasized for purposes of getting funds for research how little we know unquote the perspective expressed in the NEPA transcript would lead as shown in chapter 10 to the use of atomic bomb tests to perform human research on the psychology of panic and as shown in other case studies to decisions to hold information closely out of concern that its release could create public misunderstanding that would imperil important government programs conclusion in the atomic age captain barons atomic medicine pointed out radiation research was both the agent and the beneficiary of dramatic developments at the intersection of government and medicine when ethical questions were raised by these developments radiation researchers would be on the front line in having to deal with them the burgeoning government funded biomedical research including human radiation research required a re-examination of the traditional doctor-patient relationship at the same time the evolving role of medical researchers as government officials and advisors also posed questions about the place of doctors and more generally of scientists in service to government. End of section 7 Section 8 of the final report of the advisory committee on human radiation experiments this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org recording by Steven Sutliff final report of the advisory committee on human radiation experiments introduction part 4 the basics of radiation science the ethical and historical issues of human radiation experiments cannot be understood without a basic grasp of the underlying science this requires more than a glossary defining technical terms at least an intuitive understanding of the natural laws and scientific techniques of radiation science is necessary obviously acquiring a professional level of knowledge would require far more time than most readers can afford indeed entire careers are devoted to studying just one aspect of the field to serve the interests of democracy in a technological world however we must provide sufficient technical background for all citizens to become active participants in considering the ethical and political dimensions of scientific research what follows is an attempt to provide such a background for the events and issues discussed in this report directed toward those readers less familiar with the basics of radiation science this task was deemed important enough to deserve a distinct section of this introduction what is ionizing radiation what is radiation radiation is a very general term used to describe any process that transmits energy through space or a material away from a source light, sound and radio waves are all examples of radiation when most people think of radiation however they are thinking of ionizing radiation radiation that can disrupt the atoms and molecules within the body while scientists think of these emissions in highly mathematical terms they can be visualized either as subatomic particles or as rays radiations effects on humans can best be understood by first examining the effect of radiation on atoms the basic building blocks of matter what is ionization atoms consist of comparatively large particles protons and neutrons sitting in a central nucleus orbited by smaller particles electrons a miniature solar system normally the number of protons in the center of the atom equals the number of electrons in orbit an ion is any atom or molecule that does not have the normal number of electrons ionizing radiation is any form of radiation that has enough energy to knock electrons out of atoms or molecules creating ions how is ionizing radiation measured measurement lies at the heart of modern science but a number by itself conveys no information useful measurement requires both an instrument or measurement such as a stick to mark off length and agreement on the units to be used such as inches, meters or miles the units chosen will vary with the purpose of the measurement for example a cook will measure butter in terms of tablespoons to ensure the meal tastes good while a nutritionist may be more concerned with measuring calories to determine the effect on the diners health the variety of units used to measure radiation and radioactivity at times confuses even scientists if they do not use them every day it may be helpful to keep in mind the purpose of various units there are two basic reasons to measure radiation the study of physics and the study of the biological effects of radiation what creates the complexity is that our instruments measure physical effects while what is of interest to some biological effects a further complication is that units, as with words in any language may fade from use and be replaced by new units radiation is not a series of distinct events like radioactive decays which can be counted individually measuring radiation in bulk is like measuring the movement of sand in an hourglass it is more useful to think of it as a continuous flow of separate events the intensity of a beam of ionizing radiation is measured by counting up how many ions how much electrical charge it creates in air the Rankin, named after Wilhelm Rankin the discoverer of X-rays is the unit that measures the ability of X-rays to ionize air it is a unit of exposure that can be measured directly shortly after World War II a common unit of measurement was the Rankin Equivalent Physical REP which denoted an ability of other forms of radiation to create as many ions in air as a Rankin of X-rays it is no longer used but appears in many of the documents examined by the advisory committee what are the basic types of ionizing radiation there are many types of ionizing radiation but the most familiar are alpha, beta and gamma slash X-ray radiation neutrons, when expelled from atomic nuclei and traveling as a form of radiation can also be a significant health concern alpha particles are clusters of two neutrons and two protons each they are identical to the nuclei of atoms of helium the second lightest and second most common element in the universe after hydrogen compared with other forms of radiation though they are very heavy particles about 7,300 times the mass of an electron as they travel along these large and heavy particles frequently interact with the electrons of atoms rapidly losing their energy they cannot even penetrate a piece of paper or the layer of dead cells on the surface again but if released within the body from a radioactive atom inside or near a cell alpha particles can do great damage as they ionize atoms disrupting living cells radium and plutonium are two examples of alpha emitters beta particles are electrons traveling at very high energies if alpha particles can be thought of as large and slow bowling balls beta particles can be utilized as golf balls on a driving range they travel farther than alpha particles and depending on their energy may do as much damage for example beta particles in fallout can cause severe burns to the skin known as beta burns radioisotopes that emit beta particles are present in fission products produced in nuclear reactors and nuclear explosions some beta emitting radioisotopes such as iodine-131 are administered internally to patients to diagnose and treat disease gamma and x-ray radiation consists of packets of energy known as photons photons have no mass or charge and they travel in straight lines the visible light seen by our eyes is also made up of photons but at lower energies the energy of a gamma ray is typically greater than kilo electron volts per photon more than 200,000 times the energy of visible light 0.5 EV KEV is the abbreviation for kilo electron volts K is the abbreviation for kilo a prefix that multiplies a basic unit by 1000 if alpha particles are visualized as bowling balls and beta particles as golf balls photons of gamma and x-ray radiation are like weightless bullets moving at the speed of light photons are classified according to their origin gamma rays originate from events within an atomic nucleus their energy and rate of production depend on the radioactive decay process of the radionucleide that is their source x-rays are photons that usually originate from energy transitions of the electrons of an atom these can be artificially generated by starting appropriate atoms with high energy electrons as in the classic x-ray tube because x-rays are produced artificially by a stream of electrons their rate of output and energy can be controlled by adjusting the energy and amount of the electrons themselves both x-rays and gamma rays can penetrate deeply into the human body how deeply they penetrate depends on their energy higher energy results deeper penetration into the body a 1 MeV M is the abbreviation for mega a prefix that multiplies a basic unit by a million gamma ray with an energy 2 million times that of visible light can pass completely through the body creating tens of thousands of ions as it does a final form of radiation of concern is neutron radiation neutrons, along with protons are one of the components of the atomic nucleus like protons they have a large mass unlike protons they have no electric charge allowing them to slip more easily between atoms like a stealth fighter high energy neutrons can travel farther into the body past the protective outer layer of the skin before delivering their energy and causing ionization several other types of high energy particles are also ionizing radiation cosmic radiation that penetrates the earth's atmosphere from space consists mainly of protons alpha particles and heavier atomic nuclei positrons, mesons, pions and other exotic particles can also be ionizing radiation what is radioactivity? what causes radioactivity? as the name implies radioactivity is the act of emitting radiation spontaneously this is done by an atomic nucleus that for some reason is unstable it wants to give up some energy in order to shift to a more stable configuration during the first half of the 20th century much of modern physics was devoted to exploring why this happens with the result that nuclear decay was fairly well understood by 1960 too many neutrons in a nucleus lead it to emit a negative beta particle which changes one of the neutrons into a proton too many protons in a nucleus lead it to emit a positron positively charged electron changing a proton into a neutron too much energy leads a nucleus to emit a gamma ray which discards great energy without changing any of the particles in the nucleus too much mass leads a nucleus to emit an alpha particle discarding 4 heavy particles 2 protons and 2 neutrons how is radioactivity measured? radioactivity is a physical not a biological phenomenon simply stated the radioactivity of a sample can be measured by counting how many atoms are spontaneously decaying each second this can be done with instruments designed to detect the particular type of radiation emitted with each decay or disintegration the actual number of disintegrations per second may be quite large scientists have agreed upon common units to use as a form of shorthand thus a curie abbreviated C.I. and named after Pierre and Marie Curie the discoverers of radium is simply a shorthand way of writing 37 billion disintegrations per second the rate of disintegrations occurring in one gram of radium the more modern international system of measurements S.I. unit for the same type of measurement is the becquerel abbreviated B.Q and named after Henry Becquerel the discoverer of radioactivity which is simply a shorthand for one disintegration per second what is radioactive half-life? being unstable does not lead an atomic nucleus to emit radiation immediately instead the probability of an atom disintegrating is constant as if unstable nuclei continuously participate in a sort of lottery with random drawings to decide which atom will next emit radiation and disintegrate to a more stable state the time it takes for half of the atoms in a given mass to when the lottery that is, emit radiation and change to a more stable state is called the half-life half-lives vary greatly among types of atoms from less than a second to billions of years for example it will take about 4.5 billion years for half of the atoms in a mass of uranium-238 to spontaneously disintegrate but only 24,000 years for half of the atoms in a mass of plutonium-239 to spontaneously disintegrate iodine-131 commonly used in medicine has a half-life of only 8 days what is a radioactive decay chain? stability may be achieved in a single decay or a nucleus may decay through a series of states before it reaches a truly stable configuration a bit like a slinky toy stepping down a set of stairs each state or step will have its own unique characteristics of half-life and type of radiation to be emitted as the move is made to the next state much scientific effort has been devoted to unraveling these decay chains not only to achieve a basic understanding of nature but also to design nuclear weapons and nuclear reactors the unusually complicated decay of uranium-238 for example, the primary source of natural radioactivity on Earth proceeds as follows uranium-238 emits an alpha thorium-234 emits a beta protectinium-234 emits a beta uranium-234 thorium-230 emits an alpha radium-226 emits an alpha radon-222 emits an alpha polonium-218 emits an alpha lead-214 emits a beta bismuth-214 emits a beta polonium-214 emits an alpha bismuth-210 emits a beta bismuth-210 emits a beta polonium-210 emits an alpha lead-206 which is stable how can radioactivity be caused artificially? radioactivity can occur both naturally and through human intervention an example of artificially induced radioactivity is neutron activation a neutron fired into a nucleus can cause nuclear fission the splitting of atoms this is the basic concept behind the atomic bomb neutron activation is also the underlying principle of boron neutron capture therapy for certain brain cancers a solution containing boron is injected into a patient and is absorbed more by the cancer than by other cells neutrons fired at the area of the brain cancer are readily absorbed captured by the boron nuclei these nuclei then become unstable and emit radiation that attacks the cancer cells simple in its basic physics the treatment has been complex and controversial in practice and after half a century is still regarded as highly experimental what are atomic number and atomic weight what is an element chemical behavior is what originally led scientists to classify matter into various elements chemical behavior is the ability of an atom to combine with other atoms in more technical terms chemical behavior depends upon the type and number of the chemical bonds an atom can form with other atoms in classroom kits for building models of molecules, atoms are usually represented by colored spheres with small holes for pegs and the bonds are represented by the small pegs that can connect the spheres the number of peg holes signifies the maximum number of bonds an atom can form different types of bonds may be represented by different types of pegs atoms that have the same number of peg holes may have similar chemical behavior thus, atoms that have identical chemical behavior are regarded as atoms of the same element for example an atom is labeled a carbon atom if it can form the same number types and configurations of bonds as other carbon atoms although the basics are simple to explain how atoms bind to each other becomes very complex when studied in detail new discoveries are still being made as new types of materials are formed what is atomic number? an atom may be visualized as a miniature solar system with a large central nucleus orbited by small electrons the bonding capacity of an atom is determined by the electrons for example, atoms that in their normal state have one electron are hydrogen atoms and will readily and sometimes violently bond with oxygen this bonding capacity of hydrogen was the cause of the explosion of the airship Hindenburg in 1937 atoms that in their normal state have two electrons are helium atoms which will not bond with oxygen and would have been a better choice for filling the Hindenburg we can pursue the question back one step further what determines the number of electrons? the number of protons in the nucleus of the atom here, the analogy between an atom and the solar system breaks down the force that holds the planets in their orbits is the gravitational attraction between the planets and the sun however, in an atom what holds the electrons in their orbit is the electrical attraction between the electrons and the protons in the nucleus the basic rule is that like charges repel and opposite charges attract although a proton has more mass than an electron they both have the same amount of electrical charge but opposite in kind scientists have designated electrons as having a negative charge and protons as having a positive charge one positive proton can hold one negative electron in orbit thus an atom with one proton in its nucleus normally will have one electron in orbit and be labeled a hydrogen atom an atom with 94 protons in its nucleus will normally have 94 electrons orbiting it and be labeled a plutonium atom the number of protons in a nucleus is called the atomic number and always equals the number of electrons in orbit about that nucleus in a non-ionized atom thus all atoms that have the same number of protons the atomic number are atoms of the same element what is atomic weight the nuclei of atoms also contain neutrons which help hold the nucleus together a neutron has no electrical charge and is slightly more massive than a proton because a neutron can decay into a proton plus an electron the essence of beta decay it is sometimes helpful to think of a neutron as an electron and a proton blended together although this is at best an oversimplification because a neutron has no charge a neutron has no effect on the number of electrons orbiting the nucleus however because it is even more massive than a proton a neutron can add significantly to the weight of an atom the total weight of an atom is called the atomic weight it is approximately equal to the number of protons and neutrons with a little extra added by the electrons the stability of the nucleus and hence the atom's radioactivity is heavily dependent upon the number of neutrons it contains what notations are used to represent atomic number and weight each atom therefore can be assigned both an atomic number the number of protons equals the number of electrons and an atomic weight approximately equal to the number of protons plus the number of neutrons the normal helium atom for example has two protons and two neutrons in its nucleus with two electrons in orbit its chemical behavior is determined by the atomic number 2 the number of protons which equals the normal number of electrons the stability of its nucleus that is its radioactivity varies with its atomic weight approximately equal to the number of protons and neutrons the most well known form of plutonium for example has an atomic number of 94 since it has 94 protons and with the 145 neutrons in its nucleus an atomic weight of 239 94 protons plus 145 neutrons in world war 2 its very existence was highly classified the atomic number was developed the last digit of the atomic number 94 and the last digit of the atomic weight 239 thus in some of the early documents examined by the advisory committee the term 49 refers to plutonium styles of notation vary but usually isotopes are written as subscript atomic number chemical abbreviation superscript atomic weight or as superscript atomic weight chemical abbreviation thus the isotope of plutonium just discussed would be written as subscript 94 pu superscript 239 or as superscript 239 pu atomic weight is what is often the only item of interest it might also be written simply as pu-239 plutonium 239 or pu superscript 239