"Clean" Nukes and the Ecology of Nuclear War

Before the AEC became interested in systematic study of the biological-environmental issues, one of the Defense Department's chief concerns in this matter was the problem of constraints; that is, ensuring that nuclear strikes did not produce levels of radioactive fallout that could endanger populations in nearby friendly countries. This became an important issue in the preparation of nuclear war plans - the SIOP, or Single Integrated Operational Plan. The JCS therefore instructed the Joint Strategic Target Planning Staff to follow a constraints policy by selecting weapons for striking specific "burst points" that would "minimize local fallout in the non-Soviet areas." Given Helsinki's very close location to the former Soviet Union, setting boundaries for fallout "doses" meant that "Helsinki became the control point which had the greatest effect upon the targeting process." Soviet bloc cities were not far: for example, Leningrad, with many military targets in and around it, was 242 miles away, and Tallinn 54 miles. Accordingly, for nearby targets, the JSTPS reassigned weapons, with smaller weapons replacing larger weapons and air bursts replacing surface bursts.

Following Johnson's request, the DASA compared the impact to Helsinki from using standard nuclear weapons striking nearby Soviet targets, following the latest constraints, to the impact of using clean and "immaculate" weapons. "Clean" weapons were designed to ensure that most of the explosive yield was caused by nuclear fusion instead of fission. "Immaculate" or "super-clean" weapons were all-fusion devices that proved elusive.

According to Booth, variable meteorological conditions made it impossible to assure that nuclear strikes would not endanger the Finns. Nevertheless, DASA estimated that the "total expected dose" at Helsinki would be 91r(ads) using standard weapons with constraints, 23r using clean weapons, and 6.5r using "immaculate" weapons. As radiation sickness was associated with exposure to 100 rads or higher, 91r was close to the threshold.

This report to the AEC's General Manager by the Directors of Biology and Medicine, Military Application, and Operational Safety found that the U.S. government lacked an "adequate basis for predicting the biological and environmental consequences of nuclear warfare." In the past, the AEC had produced related studies on a hurried, ad hoc basis, a procedure that the division chiefs found unsatisfactory. Because the AEC had an "established responsibility" and a "unique capability" to forecast the long-term impact of nuclear war, it needed to fill the gap by establishing "within its headquarters staff, a group of qualified scientists."

The responsibilities of the new office would include: 1) responding to the annual request from the NSC Net Evaluation Subcommittee for "analysis of the biological and long-term effects of the radioactive fallout from a specific nuclear war situation," 2) responding "to such special studies as the President, the National Security Council, the Joint Committee on Atomic Energy, and the Commission itself have requested in the past - e.g., determination of the 'limits of massive, concentrated nuclear detonations and their byproducts which could be tolerated by the peoples of the world and by the world itself,'" and 3) providing "continuing guidance to the Commission with respect to problems arising from [its] program for the development and production of nuclear weapons which are related to the biological and environmental consequences of their military application."

The division chiefs further recommended that the AEC invite comments and suggestions from the federal agencies, especially the Department of Defense, that were "most directly responsible for determining the consequences of nuclear war, and utilizing this information for the development of national plans and policies."

In one of the annexes, the division chiefs provided background on previous AEC studies of the biological consequences of nuclear war. For example, at the request of the National Security Council, on 14 July 1958, the AEC's Willard Libby briefed President Eisenhower and the NSC on the impact of detonations on a huge scale of "dirty bombs," with a large part of the explosive yield produced by fission compared with the detonation of "clean" bombs, with fusion producing most of the yield, with far less fallout. Libby told the NSC that:

the worldwide effects of a 15,000 MT nuclear war fought with dirty bombs of 50% fission yield would constitute a serious hazard to health but most certainly not be the end of life on earth. The non-biological or physical effects - principally on the weather - would be minor. What the upper limit of massive nuclear detonations which can be tolerated is, is not very clear; but it seems that something like 50,000 MT of dirty bombs or 500,000 MT of clean ones with 5% fission would be about it. It would push the people of the world toward the limit of tolerance.

Gerald Johnson attended a meeting at the AEC and, according to Seaborg's account, he wanted to appoint a "small ad hoc committee to study the long-term effects of a nuclear attack, in particular those of fission product isotopes like Sr-90 and Cs-137. The studies would include total effects on the ecology as well as those directly affecting humans."

Having decided to go ahead with the special studies unit, Seaborg informed McNamara that the AEC was extending its studies on the effects of nuclear war. Because of that subject's importance, he was interested in clarifying "the interests, roles, and responsibilities of the AEC and the other agencies," but also in determining "how the programs of the various government agencies in this area of study can best satisfy the needs of the government" by assuring that the president and the National Security Council have "accurate and complete" information.

Toward that end, Seaborg wanted to continue and expand the AEC's research on the biological consequences of nuclear war, but also to consider the "indirect effects on people resulting from direct effect of fallout and fire on wildlife, birds, insects, domestic stock, forests, and other factors of ecological importance, and the possible effects of large numbers of nuclear explosions on local and global weather." Calling for such studies was innovative because of the implication that the heat, smoke, and dust generated by nuclear detonations could have an impact on weather patterns.

Seaborg also proposed looking into predictive issues: whether it was possible to make accurate forecasts of the "biological and environmental effects of nuclear war" and the role that such factors as weather, seasons, and warning time, among other "variations," would have in making estimates.

Agreeing with Seaborg that the "multi-variate and complex elements" of nuclear war deserved continuing investigation, Johnson recommended that Gilpatric sign a letter supporting the proposal along with the creation of a working group that the AEC would chair. The letter recommending additional areas for research in topics of special interest to the Defense Department such as the impact on weapons effects of such elements as yields and "burst geometry" and the impact of various parameters (target systems, etc.) for estimating mortalities and injuries. Gilpatric requested an initial report by 1 May 1962.

In his reply, Seaborg informed Gilpatric that as soon as the working group was established it would look into the "problem areas" that the Deputy Secretary had mentioned. Seaborg made no commitment about the timetable for completing reports only that he would give "high priority" to establishing "realistic dates."

This constituted the official AEC announcement that Hal Hollister would direct the new Technical Analysis Branch (TAB) in the Division of Biology and Medicine.

Johnson received from Hollister a detailed outline of the first iteration of a report on the environmental and biological consequences of a nuclear attack using clean nuclear weapons. With the "starting time" as the immediate aftermath of an attack. Thus, blast destruction, radiation, and other effects would be "inputs" for an analysis of the consequences.

The Defense Atomic Support Agency (formerly the Armed Forces Special Weapons Project) prepared the first study in response to the Seaborg proposal, although the spirit of the report diverged from the AEC’s intent. DASA estimated the results of nuclear strikes on the Soviet Union caused by attacks with three different total megatonnages: in the range of 1000, 3000, and 10,000.[2] For each weight, DASA estimated the results of using standard or clean weapons, air bursts or surface bursts, and combined military/urban-industrial targets or military targets only. For a 1000-megaton attack DASA found that the surface bursting of clean weapons caused the same level of casualties as air bursts of standard weapons. Not surprisingly, the high attack, around 10,000 megatons, involving surface bursts of standard weapons striking combined military and urban-industrial targets produced the highest level and percentage of fatalities: 166 million, 79 percent. Surface bursts of clean weapons produced highly lethal effects “as the weight of attack increases owing to the small but accumulating contributions of radio activity.”

One of the conclusions was that it was "quite feasible, in attempting almost any military strategy to inflict simultaneously almost any desired level of population destruction ranging from a few percent to almost complete obliteration." Lower percentages of fatalities could be reached by excluding from the target list "the several dozen military headquarters located in cities." Casualties could also be minimized by surface bursts against hard targets using clean weapons. Nevertheless, according to DASA, surface bursting of clean weapons "tend ... to become more lethal as weight of attack increases owing to the small but accumulating contributions of radioactivity."

Reporting on progress, Johnson informed Seaborg that Hal Hollister of the AEC’s Division of Biology and Medicine would “undertake a special nuclear attack study: an assessment of the immediate effects and the longer term post-attack biological and ecological effects of a nuclear attack, comparing the results under variations in weights of attack and degrees of weapon ‘cleanliness.’" The Defense Department was cooperating by providing data, for example, by the Defense Damage Assessment Center [DDAC], which had performed computer runs of the immediate casualty data on the basis of various parameters. The DDAC had offices at the Pentagon and at the Alternate National Military Command Center (“Raven Rock”) near Fort Ritchie, Maryland, so that it could do its work during a wartime emergency (unless the command history received a direct hit).[3]

Colonel Carter reported on the reasons for delay of the DDAC/ DASA study whose first iteration was in Document 8. Collection of data was difficult, parameters had changed [as described in the attachment], and the task's complexity had "exceeded all past experience in this area." The final version of the study, promised for 4 September 1962, has not yet surfaced.

Apparently drawing on the DASA studies, this excised memorandum focuses on the impact of air burst versus surface burst, clean versus standard weapons, and weight of the attack, among other considerations, on Soviet bloc fatality levels.

Having learned that one of the parameters of DASA's "immediate casualty analysis" was a "prevailing westerly wind." Johnson asked for a "rerun" of the "computations." For the sake of a more complete analysis, he believed DASA should take into account a "prevailing adverse wind condition."

Following up on Johnson's request, General Booth sent Johnson the re-computed casualty data using different wind conditions. An easterly wind, blowing fallout from surface explosions of standard nuclear weapons against military targets in the western Soviet Union, could cause 16-19% casualty rates in East Germany and Rumania. Under some circumstances, not specified in the declassified text, Western European fatalities could reach 10 million. By contrast, using clean weapons would drop casualties in East Germany and Rumania to 2 percent levels.

This is another heavily excised iteration of the DASA study, focusing on the use of "clean" weapons.

Drawing heavily on the DDAC report, the AEC study looked at attacks on military and combined military/industrial target systems, with attacks of varying weight in terms of total megaton yield, surface or air burst, weapons of various yield, and standard vs. clean weapons. The conclusions included a number of generalizations, for example, that "clean weapons lead to reduced fatalities and casualties for surface bursts, especially in the larger attacks," and that "clean weapons expose the plant life to lower doses." Moreover, clean weapons reduced the dose of "internal emitters" (isotopes inhaled or ingested), although that would not be of great help to an unsheltered population. In addition, "survivors of the clean-weapon attacks very clearly survive with a 1ower lifetime gamma exposure dose, a factor relevant to the subsequent state of their health." Defense officials were critical of this report [See Documents 18A-B]] because they believed that it made generalizations without assessing their significance, among other problems.

This compilation of material constitutes a record of the briefing material, and of the briefing itself, that Hollister prepared for Dr. Vincent McRae, a key person in the Office of Science and Technology, and one of the few African-Americans then working in government at that level. The briefing material included detailed discussion of U.S. government nuclear war damage assessment capabilities and an overview of the "TAB Program" and its objectives. During their discussion, McRae told Hollister that he believed that the "total" research program should be "directed to the question of what happens and what to do after one comes out of shelter."

The TAB program overview suggested that the United States had made important defense decisions without taking into account the "post-attack environment," such as the H-bomb decision, the decisions to deploy ICBMs in "'hard' sites which are likely to attract heavy attack with such consequences as heavy local fallout from ground bursts," and the "decision to defend Western Europe with nuclear weapons." Thus, "Nuclear strategy and weapons programs should preferably be adopted with an adequate understanding of their potential biological and environmental consequences."

Looking closely at Soviet Communist Party Chairman Nikita Khrushchev's statements about the catastrophic effects of nuclear attacks, Captain McCoy found a rational basis for the assertion that a 100-megaton weapon dropped on Western Europe could "hit" the Soviet Union. The equivalent of a 180-megaton weapon, if its explosive yield and its destructive impact were evenly distributed, could kill the entire population of the United States. A 400-megaton weapon could have the same impact on the geographically larger Soviet Union. While such feats were technically impossible, the detonation of larger weapons on populated areas produced devastating results.

Strope gave the AEC study a critical review, finding it "quite superficial and unnecessarily vague" because of insufficient quantitative analysis and failure to assess the significance of findings, among other problems. An interesting reference is to a finding by the National Academy of Science's Advisory Committee on Civil Defense, which had a Subcommittee on Postattack Ecology: that the "ecological effects attributable to fires would be much greater than those attributable to nuclear radiation."

Several days after Strope sent his critique of the AEC study, Johnson followed the bureaucratic niceties and sent a milder version.

In a memorandum to Gerald W. Johnson, the director of the Net Evaluation Subcommittee General Leon W. Johnson observed that a recent AEC contribution to NESC's annual assessment of nuclear war "emphasized the fact that little was known concerning the question of the combined effects on survivors of radiation, thermal radiation, blast, fires, floods, substandard diet, substandard sanitary conditions, and lack of medical care and services, and that this area urgently needed study." General Johnson supported further AEC study of these problems, which led Gerald Johnson to write to Seaborg to continue such studies as a "matter of priority" because of their importance.

The AIBS symposium consisted of the following presentations: “Types of Catastrophes and their Physical Proportions,” providing general information of the physical results of a massive nuclear attack,[4] “Behavior of Radionuclides in Ecosystems,” describing the cycling of fission products from soil to grass to cows to milk, “Effects of Fire on Major Ecosystems,” on the effects of simultaneous ignition of fires in non-urban areas, “Effects of Ionizing Radiation on Major Ecosystems,” paralleling one of the co-author’s essay in Scientific American on the impact of chronic radiation exposure on pine-oak forests and fields of weeds,[5] “Homeostasis and Succession in Disturbed Ecosystems,” presentation of data on differential species kill caused by the Lockheed aircraft nuclear reactor in Dawsonville, Georgia, and “Biological Interactions Within Ecosystems,” on the implications of insecticide spraying for recovery of ecosystems after a nuclear war.

According to the assessment by TAB staffers of the presentations, most of the authors were overly preoccupied with radiation effects: “there seemed to be a lack of interest in the long-term recovery aspects of ecosystems following a nuclear catastrophe.” The participants generally agreed that the long-term recovery problem was “so vast and complex and the available information which is needed for prediction so sparse that much research will be needed to permit more definitive speculation on the ecological consequences of a nuclear war.”

Hollister justified the TAB study by arguing that a "better understanding of the biological and environmental consequences of nuclear war should contribute to more enlightened decisions on strategy and foreign policy, military operations, weapons systems evaluation, nuclear stockpile composition, civil defense, arms control, and postattack recovery." For Hollister, the proper focus should be "full appraisals of the longer-term consequences of nuclear attacks on the health of people or on their living environment," which "to our knowledge [have] never been made in this country."

Besides emphasizing the importance of systems analysis, Hollister called for "major improvement in the analysis of existing information" and the systematization of knowledge on a range of subjects. "Properly systematized current knowledge in agriculture, forest and range management, soil conservation, wildlife management, water resource management, public health, and vital statistics can ... help to provide an adequate background description of the preattack (undisturbed) environment and thus give a basis for estimating the effects of a nuclear attack." Hollister was not yet considering broader impacts, such as the effect of nuclear war on the climate, as Seaborg had proposed in his original plan, although eventually TAB would sponsor such research.