Canadian Coalition
for Nuclear
Responsibility





Regroupement pour
la surveillance
du nucléaire

Estimating Lung Cancers

or,

It's Perfectly Safe,
But Don't Breathe Too Deeply


Part 3


Estimating Lung Cancer Deaths
Caused by Permissible Radon Exposures
in New Homes in Elliot Lake, Ontario


by Dr. Gordon Edwards



a summary of testimony presented to
the Ontario Environmental Assessment Panel
on permissible levels of radon contamination
for new homes in the town of Elliot Lake



EXHIBIT 12

Letter from Karl Z. Morgan to James Schlesinger



Atlanta, Georgia 30332
(404) 894 3720
May 25, 1977

Mr. James Schlesinger
Executive Office of The President
Energy Policy and Planning
Washington, D.C. 20500

Dear Mr. Schlesinger:

As a follow-up of my letters of March 30, 1977 and May 23, 1977, and following a lecture I gave recently at the University of Tennessee, in Knoxville, Tennessee, several persons at ORNL have contacted me suggesting that perhaps I would be willing to lend my support to a current ORNL proposal that the LMFBR-CRBR program be continued by replacing the plutonium fuel with uranium-233 and the uranium-238 with thorium-232. I indicated to them that were I to approve such a program, it would be only with a number of qualifications and with assurance of many program changes.

We certainly need information on the thorium/uranium-233 cycle, but I'm not sure this is the cheapest and best way to get the information needed. One of the greatest causes of my trepidation relates to the ORNL management and its past record of blind support of the LMFBR in spite of knowledge of its very serious shortcomings. ORNL management should have been objective and should have insisted on following the best course -- not the politically expedient one. Instead, it only did those things that would please the AEC (and later the ERDA). It did not display any vision or desire to be successful -- rather, it wanted to preserve status quo, to keep the money rolling, and everyone on the payroll. Any ideas in Oak Ridge contrary to the Washington approved course (prior to my leaving ORNL in 1972) were suppressed. Even studies relating to such important questions as brittle fracture of the reactor containment vessel, common mode failure and emergency core cooling were suppressed, the findings depreciated and not published.

Perhaps management at the various Oak Ridge operations can change this poor record, but I'm not sure it can or that recent events in Oak Ridge would justify our encouragement. For example, when the Mancuso Program (to which I am a consultant) indicated there was an increase on statistical significance in four types of cancer (myeloid neoplasm, breast cancer, pancreatic tumors and lung cancer), Mancuso was informed shortly afterwards that his program would no longer be funded by ERDA, and we learned that Jim Leverman plans to reincarnate this program in Oak Ridge (probably under the supervision of ORAU) to be conducted by Drs. C. C. Lushbaugh and Edith Tompkins. This change could be at a very great cost and would represent a serious discontinuity of scientific effort. One can only suppose that the new Oak Ridge team must get the right answer (i.e. prove there is NO radiation risk to Hanford and Oak Ridge Workers) if it cares to have a continuation of funding. I believe Dr. Lushbaugh would try to be objective, but I have good reason to question if this would be true of Dr. Tompkins.

Perhaps at this stage there is something you can do to prevent this transition, My suggestion would be to ask OSHA to take over the support of this Mancuso program and, hopefully, it would see the wisdom of asking Dr. Mancuso to continue his studies and continue the services of the two British scientists, Drs. Alice Stewart and George Kneale, that have contributed so much to the success, scientific stature, and independent, unbiased evaluation of these data from Hanford and Oak Ridge.

Actually, the cancer risk at Hanford, as reported by Mancuso, Stewart, and Kneale, in comparison with other occupational risks, is rather small. The only problem is that many of the early ORNL, Hanford, and AEC employees have been saying repeatedly in public (and contrary to my cautionary warning) that there are NO radiation risks from work at these facilities. The word NO is such a small number that true scientists retrain from using it. Surely, it is a conflict of interest for this program to be conducted in Oak Ridge under contract with either ERDA or NRC.

I am a strong supporter of nuclear energy, but not at any cost. Many people agree with me that the AEC, NRC, ERDA, ORNL, etc. are often their worst enemies and get in the way of those of us who believe we can build and operate a nuclear energy industry that is acceptably safe and presents occupational and environmental risks that are far less than those of a well conducted fossil fuel power program. After all, the risks from NOx, SOx, COx, hydrocarbons and particulates in terms or lung carcinoma, chronic bronchitis and emphysema are very real and some of us are very concerned about the effects of CO2 on the climate. I am all for Jimmy Carter's emphasis on conservation, solar and fossil fuel energy for our power, but I believe with your help our country can take the lead in placing nuclear power in its proper place.

In closing, and in contrast with the faults at ORNL and Oak Ridge which I mentioned above, I would like to close with the reminder that some of our country's best scientists have worked at ORNL and a few of them are still there.

Best personal regards.


cc John F. Ahearne

LIST OF REFERENCES

  1. "HAM COMMISSION REPORT" -- Report of the Royal Commission on the Health and Safety of Workers in Mines, by James M. Ham (Commissioner). Government of Ontario, Toronto, 1976.

  2. PROCEEDINGS of a Congressional Seminar on Low Level Ionizing Radiation. Environmental Policy Institute, 317 Pennsylvania Ave SE, Washington DC, 20003, July 1977.

  3. "Radon Daughter Cancer in Man: Factors in Exposure Response Relationships" by V.E. Archer, E.P. Radford, and O. Axelson. Radiation Research 1978 (to appear).

  4. "The Colorado Plateau: Joachimsthal Revisited? An analysis of the Lung Cancer Problem in Uranium and Hard Rock Miners", by Arthur R. Tamplin and John W. Gofman. Testimony Presented at Hearings of the Joint Committee on Atomic Energy, 91st Congress of the United States, January 28, 1970.

  5. "MOH REPORT" -- Elliot Lake Protection from Radiation in New Housing. Report to the Environmental Assessment Board by the Ontario Ministry of Housing, with an Appendix by Jan Muller and R. Kusiak. February 1978.

  6. "The Cancer and Leukemia Consequences of Medical X-Rays" by John W. Gofman. Osteopathic Annals, Nov. 1975.

  7. "Health Effects of Radon-222 from Uranium Mining", by Robert O. Pohl. Search, Vol. 7, No. 8, August 1976.

  8. Letter from Karl Z. Morgan to James Schlesinger, May 25, 1977 (dealing in part with the epidemiological study of cancers in Hanford Workers by Thomas Mancuso, Alice Stewart, and George Kneale) -- reproduced in this text as Exhibit 12.

  9. "The Biological Effects of Radiation: Ten Times Worse Than Estimated", by Arthur R. Tamplin. Natural Resources Defense Council, 917 15th Street NW, Washington DC, 20005, August 1977.

  10. "The Plutonium Controversy", by John W. Gofman. Journal of the American Medical Association, Vol. 236, July 19, 1976.

  11. Mathematics in Today's World, edited by Gordon Edwards, Science Council of Canada, Ottawa, 1974. Limited edition. Copies available in all university libraries in Canada.

GLOSSARY

Although it is not necessary to understand all of the technical jargon in order to understand the problem of radon gas in buildings, here is a set of explanations which you can refer to if you wish. Don't use it unless you feel you have to.

Radioactivity is the property of certain atoms (which are not stable) to spontaneously disintegrate by emitting either energetic particles or rays of pure energy (or both) from the nucleus or centre of the atom.

The half-life of a radioactive substance is the time required for half of its atoms to disintegrate.

The daughters of a radioactive substance are the other substances which are created as byproducts in the process of radioactive disintegration; in many cases, the daughters of a radioactive substance are also radioactive.

Ionizing Radiation is the term used to describe the various energy forms which can be emitted by the disintegration of radioactive atoms; these include

Exposure to even low levels of ionizing radiation can cause cancer and/or genetically defective children in the exposed population. These effects are caused by sub-microscopic damage to the cells of the body which causes some of them to reproduce in an abnormal fashion.

Gamma Radiation (   ) is the most penetrating of all forms of ionizing radiation, capable of penetrating thick layers of metal; it is given off by the radioactive disintegration of such substances as radium-226, and is similar in nature to x-rays. (Radium-226 is primarily an alpha-emitter, however.)

Beta Radiation (   ) is the next most penetrating form of ionizing radiation after x-rays and-gamma rays; it actually consists of high velocity particles called beta particles or electrons.

Alpha Radiation (   ) is the least penetrating form of ionizing radiation, unable to penetrate through a sheet of paper; it consists of high velocity particles (called alpha particles) which are more than 7000 times heavier than electrons.

Linear Energy Transfer (LET) measures the relative amount of damage done by a particular type of radiation per unit distance travelled. It is inversely related to the penetrating power, but not in a simple way. The most penetrating types of radiation (gamma, x, beta) are referred to as "low LET radiation", while the least penetrating types (alpha, neutrons) are called "high LET radiation". High LET radiation is far more damaging per unit dose than low LET radiation.

A curie (Ci) is a measure of radioactivity in disintegrations per second; one curie corresponds to the radioactivity in a gram of pure radium.

A picocurie (pCi) is a trillionth (i.e. a millionth of a millionth) of a curie.

Radon is an alpha-emitting radioactive gas with a half-life of 3.8 days. It is a daughter of radium-226; and it gives rise to other radioactive substances known as radon daughters, most of which are also alpha-emitting substances.

One working level (WL) designates a concentration of 100 picocuries of radon daughters per litre of air (abbreviated as 100 pCi per l)

A working level month (WLM) is a measure of human exposure to radon daughters. One WLM is equal to the concentration of radon daughters, measured in working levels, times the number of hours of exposure, divided by 170. Thus a man exposed to 1 WL for 170 hours (approximately one month's exposure at 40 hours per week) will accumulate an exposure of 1 WLM.

A rad ("radiation absorbed dose") is a measure of how much energy is absorbed by tissue when exposed to a certain source of ionizing radiation. Technically, 1 rad corresponds to 100 ergs of energy being absorbed in each gram of tissue exposed to ionizing radiation.

A rem ("radiation equivalent man")is a measure of the ability of a given dose of radiation to do harm to living cells (thereby causing a predictable increase in cancer, or in genetic defects to the children of people whose gonads have been exposed to ionizing radiation). For low LET radiation, 1 rem corresponds almost exactly with 1 rad of exposure; but for high LET radiation, each rad of exposure corresponds to 10 or 20 rems, because of the much greater relative damage which is done to living cells by high LET radiation.

A millirem (mr) is a thousandth of a rem. The natural background radiation to which we are all exposed as a result of cosmic radiation from outer space and naturally occurring radioactive substances is about 100 millirem per year, or about 0.01 millirem per hour.

The quality factor associated with a given type of radiation is the factor which must be used to convert a radiation dose measured in rads to the equivalent number of rems. For gamma radiation, the quality factor is 1 (1 rad = 1 rem), but for alpha radiation, the quality factor is about 20 (1 rad = 20 rems).

The linear hypothesis states that the extra cancers and genetic defects that will occur in a given population as a result of exposure to ionizing radiation is directly proportional to the sum total of all of the individual doses received by all the members of the population.

NOTES

  1. The shortest distance between two points on a sphere is not a straight line, but a "great circle" -- that is, a circle which has the same radius as the sphere itself. However, if a "line" is defined as the shortest distance between two points, then these great circles are in fact "lines" on the surface of the sphere, since they do represent the shortest possible paths joining points on a sphere. The technical term for such a curved "line" is "geodesic". By definition, a geodesic is any path on a curved surface which provides the shortest distance between any two neighbouring points along the path.

  2. Other changes of behaviour are, of course, possible. A culture of bacteria will often grow exponentially until it exhausts its food supply, whereupon it will suffer a sudden catastrophic collapse. In other cases, where there are predator-prey relationships at work, a cyclic rise and fall of animal populations is frequently observed. However, when a species of bird or mammal is free from serious competition or predation, the logistical growth model seems to offer a good description of what happens in a natural setting.

  3. Consider the following words by Dr. Donald Miller, Head of Biomathematics at the Canadian National Research Council, addressing a senior seminar of applied mathematicians in Ottawa on March 5 1974: (Reference 11, pages 160-162)

      "Are ... people satisfied with the results of mathematical modelling? ... I think generally that they are not satisfied when the problems involve very complicated systems -- as they invariably do in ecological studies, in regional planning, and in studies of pollution or energy supply. I recently heard the former director of the Marion Lake Project, one of Canada's contributions to the International Biological Programme, make the comment that he was not convinced that mathematical modelling was any help at all in the study of ecological systems....

      "In many such projects, not enough care is devoted to the formulation and testing of the mathematical description. In its most fundamental terms, this means that we, the mathematical community, might have forgotten something that we should have learned many years ago, under the heading of the scientific method. We all know how that goes; one looks at a system and inductively frames a hypothesis, deductively works out the consequences of this hypothesis in a form that can be tested, experimentally tries to verify or disprove the hypothesis, and returns to frame a new hypothesis on an improved basis. This seems simple enough, and most people in this audience, I'm sure, are feeling a bit insulted. But the fact is that we do not seem to be doing it. We are not following the basic philosophy of science." (Emphasis added)

  4. These Proceedings are 360 (plus xxv) pages long. The bulk of the text is actually an anthology of about forty short papers which were specially prepared by the participants. Each of these papers deals in considerable detail with specific applications of mathematical methods to real-life problems arising in Federal Government Departments in Ottawa, using an absolute minimum of technical jargon and no intimidating mathematical symbolism. The Proceedings have also been translated into German and distributed by the West German Government.

  5. There is an impressive list of references provided by the Ham Commission Report (our reference 1), but they are limited to the study of uranium miners. It is perhaps worth noting, in another context, that the two most potent carcinogens in tobacco smoke are now known to be benzopyrene (a cancer causing aromatic hydrocarbon which is also present in automobile exhaust) and polonium-210 (one of the more persistent radon daughters).

    As already remarked in the summary (page iii), phosphate ore is relatively rich in uranium. As a result, radon gas is slowly released from the phosphate fertilizer which is used on most tobacco crops. Being heavy, the gas accumulates somewhat before dissipating, and the short-lived radon daughters (which carry an electrical charge) promptly attach themselves to microscopic dust particles. These dust particles, in turn, adhere to the sticky, resinous hairs which grow on the underside of the tobacco leaves. These short-lived daughters will all disintegrate within a few hours after being formed, leaving a deposit of the radioactive substance lead-210 (with a half-life of 21 years) in the tobacco leaves.

    When the tobacco leaves are harvested, cured, shredded, rolled into cigarettes, and sold in the stores, they still carry a burden of lead-210 with them. Polonium-210 is a radioactive daughter of lead-210, and, like its parent, it is a solid at normal temperatures. However, when a smoker draws on his or her cigarette, the intense localized heat at the burning tip of the cigarette is enough to volatilize both substances. Thus the chronic smoker ends up with a deposit of lead-210 and polonium-210 in his or her lungs.

    For evidence on the carcinogenicity of polonium-210, see the reference cited in Figure 5 on page 16. For more information on this topic, and for further references, see "Tobacco Radioactivity and Cancer in Smokers" by Edward A. Martell, in American Scientist, volume 63, July-August 1975, pp. 404-412. Dr. Martell has been a staff member at the National Centre for Atmospheric Research in Boulder, Colorado for many years, and has written widely on the subject of radioecology.

  6. As far as medical science can tell, carcinogens act directly on the nucleus of the cell, causing random damage to the chromosomes and DNA molecules contained therein. Most of the cells so damaged are either killed or sterilized. However, in a very few cases, one of these damaged cells may survive the injury and still be capable of reproducing. Such a cell may become a cancerous cell, if it begins to proliferate in an undifferentiated or "cancerous" manner. On the other hand, if a reproductive cell is damaged in this way, it can lead to genetic deficiencies in the offspring -- and if an embryonic cell is so affected, the normal development of the fetus can be disrupted. For this reason, it is recognized that substances having a carcinogenic effect will also have a genetic and a teratogenic effect. It is also widely believed that since these effects take place in a random manner at the cellular level, there is no such thing as a "harmless" dose. Any individual dose, however small, is able to produce gross malignancies and deformities if it is administered to a sufficiently large population.

    Consider the following quotations from the Proceedings of a Public Forum on Policies and Poisons held in Toronto, on November 15 1977, under the auspices of the Science Council of Canada and the Canadian Public Health Association:

      "... there is good circumstantial evidence that 80 percent of human cancers are environmental in origin...." (page 11)

      "There are occasions when it is known that there are severe risks attendant upon exposure to certain substances and yet no action to control them is undertaken. This appears to be a sort of 'paralysis by analysis'. For example, the risks associated with both asbestos and radiation were well-known to the medical profession in the 1930's, and yet no preventive or regulatory action appears to have been taken." (page 15J

      "The National Institute of Occupational Safety and Health's position ... is that 'excessive cancer risks have been demonstrated in all fiber concentration studies to date. Evaluation of all available human data provides no evidence for a threshold or for a safe level of asbestos exposure'," (Page 21)

      "It is necessary that we should strive for as near zero risk in the workplace as is technologically possible to achieve. For known carcinogens the level of exposure should be zero. For non-carcinogenic agents the level of permissible exposure should be revised downwards from that point at which there are gross effects on society." (pages 17-19)

  7. The sum total of all the doses administered to the population is also called the "integrated dose". According to the linear hypothesis, this "integrated dose" is proportional to the total number of damaged cells, of which a certain fraction will become cancerous. Thus the number of cancers can be predicted once the integrated dose is known.

  8. This straight-line relationship between integrated dose and cancers is called a linear relationship; hence the name for the linear hypothesis. (See note 16 please!)

  9. Dr. Morgan is an esteemed member of the Health Physics community. He is one of the founding members of the International Commission on Radiological Protection, and is today the only emeritus member of that Commission: see also the biographical sketch given earlier.

  10. Dr. Morgan has written an excellent article entitled "Cancer and Low Level Ionizing Radiation" in the September 1978 issue of the Bulletin of the Atomic Scientists (pp. 30-41). In this article, Dr. Morgan reviews recent medical evidence which shows not only that the threshold theory is probably wrong, but also that "the cancer risk from exposure to ionizing radiation is much greater than was thought to be the case some years ago." He then gives six documented arguments to show why even the linear hypothesis may consistently underestimate the carcinogenic powers of radiation at low levels. Immediately following the Morgan article, in the same issue of the same magazine, is another entitled "The Risks for Radiation Workers", written by Joseph Rotblat. It is also well worth reading, and much to the same effect.

  11. Plutonium-239 is one of the most well-known examples of an alpha emitter. Since the radiation from plutonium has little penetrating power, plutonium can be stolen and transported with relative ease. However, when inhaled into the lungs, it is extraordinarily toxic. A barely visible speck of plutonium weighing only a few thousandths of a gram can, if inhaled into the lungs, cause death within hours by massive fibrosis of the lungs. An invisible speck of plutonium only a few thousandths of one thousandth of a gram (in other words, a few micrograms), if inhaled into the lungs, may cause a fatal lung cancer to develop many years or even decades after exposure, with almost 100 percent certainty. See the article by Dr. John Edsall, Professor Emeritus of Biochemistry at Harvard University, entitled "Toxicity of Plutonium and Some Other Actinides" -Bulletin of the Atomic Scientists, September, 1976.

  12. Once alpha emitters are inside the body, they cannot be detected by any external instruments. The degree of internal contamination can only be inferred by such things as urine analysis and sputum analysis, which give only crude results.

  13. Neutron radiation, like alpha radiation, is also more effective in causing cancer than either beta or gamma radiation. Although the same amount of energy will be delivered to the tissues by a given dose of radiation, no matter whether it is made up of neutrons, alpha particles, beta particles, or gamma rays, it is known that a higher density of ionization is caused by alpha particles and neutrons than by the other types of ionizing radiation. Higher density of ionization means that more chemical bonds can be broken, and therefore greater biological damage can be done, per gram of tissue exposed. See "linear energy transfer", "rad", "rem", and "quality factor" in the glossary (pages 43-44).

  14. Several hypotheses have been advanced to explain why this should be so, but none of them has been thoroughly tested. According to one theory, there is overkill at high doses (cells which would have developed into cancer cells are instead killed by the high dosage) and therefore, at low doses, more cancer is observed per unit dose. Another theory is that the cell membrane is more effectively damaged at low dose rates than at high dose rates, thereby allowing other carcinogens (such as chemical carcinogens) easier access to the nucleus. (If this theory is correct, then not only alpha radiation but all forms of ionizing radiation should be more effective in causing cancer at low dose rates.) Still other theories deal with the distribution of alpha emitters inside the body; if a "warm particle" or a "hot particle" is lodged in the lung, it is believed by some that such a particle may be more effective in causing cancer than if the same total dose were evenly distributed throughout the lung. But all of these theories are conjectural, and so we will limit ourselves to discussing the experimental and epidemiological evidence which indicated that more cancer is observed per unit dose at low dose rates of alpha exposure, whatever the reason for that might be,

  15. See reference 2, as well as exhibits 1 and 2 on pages 9 and 10.

  16. Since this was written, I have received a list of 12 references from Bob Wilson, Director of the Health and Safety Division of Ontario Hydro, which are supposed to provide evidence indicating that the linear hypothesis is conservative for low level alpha radiation. Although I have not yet had time to do a thorough review of all of these papers, it is clear that some of them do not suggest a different conclusion from that stated in the text.

    For example, the very first reference given by Mr. Wilson is the famous paper by Sevc, Kunz and Placek, which appeared in Health Physics in June of 1976, entitled "Lung Cancer in Uranium Miners and Long Term Exposure to Radon Daughter Products". In the concluding paragraph of that paper, the authors state that "the estimate of risk of low doses, obtained by means of linear extrapolation of the relationship between higher doses and effect in a heterogeneous population, need not under all conditions represent the maximum possible risk." In other words, the linear hypothesis may not be conservative at low doses.

    Mr. Wilson also cites "Sources and Effects of Ionizing Radiation", the 1977 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Annex G of the UNSCEAR Report entitled "Radiation Carcinogenesis in Man" lists three studies which are supposed to confirm the conservatism of the linear hypothesis for low level alpha radiation. The first study is the paper by Sevc, Kunz, and Placek just referred to. The second is co-authored by Dr. Victor Archer, who has since changed his mind about the linear hypothesis as a result of more detailed analysis of all the existing evidence. The third study is my reference 1, the Ham Commission Report, which states: "This analysis is most emphatically not offered as the basis for any estimate of risk per unit dose. . . . [which would be a trivial task if the Linear hypothesis were true]. It should also be possible . . . to accommodate the idea of a response more than proportional to cumulative dose." (from Appendix C, "Radiogenic Lung Cancer in Uranium Miners 1955-74"). Thus none of the three UNSCEAR references indicates an unqualified confirmation of the linear hypothesis, and indeed at least two of them explicitly include the possibility of non-linearity at low doses.

  17. For more information about Dr. Archer, see the biographical notes.

  18. For more information about Dr. Gofman, see the biographical notes. The data on which Dr. Gofman bases his calculations are the same as those used in the Ontario Ministry of Housing's Table 1 and Table 2.

  19. "It is generally assumed that the risk of radiation induced cancer is proportional to the exposure and that there is no absolutely safe threshold below which the risk is zero. It should be borne in mind, however, that no direct proof of carcinogenic effect, at extremely low doses, exists at this time so the assumption of "no threshold" is conservative " (MOH Report, reference 5, page 5)

    It is indeed strange that the Ministry of Housing should consider that no evidence provides a proof of conservatism, especially since, in Appendix C of the Ham Commission Report (reference 1) the threshold hypothesis is tested and "easily discredited" on solid statistical grounds. The report then goes on to say:

    "The possibility of a 'safe' threshold dose cannot be excluded by these, or any other finite amount of data. However, further analyses, to be reported in full elsewhere, have shown that, to be at all plausible in relation to the Ontario experience, a postulated threshold would have to be lower than 10 WLM."

    This is not very encouraging to those who still believe in a safe threshold!

  20. According to Dr. Muller's analysis (in reference 5), the volume of air inhaled daily by men and women was obtained from ICRP Publication 26, as was pertinent data on the mass of the male and female lungs at different ages. It was also assumed that the retained fraction of radon daughters in the lungs was 70 percent, that there is no biological effect during the first five years of exposure to radiation, and that all radiation-induced deaths occur within 25 years of initial exposure. Nevertheless, the details of his calculation are very fuzzy, and his results are extraordinarily low. For example, the female mortality figures calculated by Dr. Muller are less than half as large as the ICRP estimates, and the loss of life expectancy for females is also far lower (less than a quarter, in most cases) than the ICRP estimates, as can be seen from MOH Table 6. Why should there be such a wide discrepancy ?

  21. See note 5 regarding lead-210 and polonium-210 in tobacco smoke.

  22. For more information on Dr. Stewart, see the biographical notes. Her completed work was published as "Radiation Dose Effects in Relation to Obstetric X-Pays and Childhood Cancer" in Lancet 1185 (June 5, 1970).

    The findings of her very ambitious epidemiological studies have been confirmed by other studies done by Dr. Brian McMahon of Harvard University ("X-Ray Exposure and Malignancy", Journal of the American Medical Association, v. 183, 1963) and Dr. Irwin Bross of the Roswell Park Memorial Institute for Cancer Research in Buffalo ("Leukemia from Low-Level Radiation", New England Journal of Medicine, v. 287, 1972). Dr. Bross' results come from a study of 13 million human beings in three states; an updated account of his findings can be found in reference 2.

    More recently, Dr. Stewart and her statistician colleague George Kneale have assisted Dr. Thomas Mancuso in studying the cancer incidence among workers at the Hanford Plutonium Works in Washington State. The results of this study have appeared as "Radiation Exposures of Hanford Workers Dying from Cancer and Other Causes" in Health Physics, 33, 1977.

    Using statistics on over 24,000 ex-employees at the Hanford nuclear facility, the authors (Mancuso, Stewart, and Kneale) have shown that as small a dose as 12.2 rads accumulated radiation exposure could lead to a doubling of the normal incidence of most cancers. According to the study, for cancers of the pancreas or lung, the "doubling dose" may be as low as 6.1 rads, and for cancers of bone marrow, the "doubling dose" is less than 2.5 rads. These latter cancers, it is worth noting, are often induced by alpha emitters such as plutonium, or radon daughters, or radium.

    It is a sad commentary that both Dr. Bross' funding and Dr. Mancuso's funding hare been terminated, so that these men are unable to complete the investigations which they have begun. In a similar way, the around-breaking work of Gofman and Tamplin was terminated back in the late 1960's with much acrimony. I have included as an exhibit a revealing letter, written by Dr. Karl Morgan to James Schlesinger on May 25 1977, concerning the "biopolitics" which seems to be at work in suppressing scientific researches which do not conform to the official dogma that radiation is relatively harmless at low doses.

    Dr. Morgan's letter appears as Exhibit 12.

  23. Testimony given at the Elliot Lake Environmental Assessment Hearings indicated that any gouges in the sealant (caused perhaps by children playing roughly, or by men sliding heavy furniture over the floor) would allow almost as much radon gas into the basement as if there were no sealant whatsoever.

    The situation is made even worse by the fact that radiation is not perceptible to any of our senses, and most homeowners cannot make measurements of the radon gas levels in their own homes. Thus there could be serious deterioration of the protective systems, which could go undetected for a very long time.

  24. In 1973, the U.S. Environmental Protection Agency published a substantial report entitled "Environmental Analysis of the Uranium Fuel Cycle", EPA-520/9-73-003-B. According to the Report, about 200 extra lung cancer deaths per century could be expected to occur among members of the general population as a result of the radon gas emissions from a typical uranium tailing pile (assuming that only 5 percent of the radon gas produced actually escapes into the atmosphere, and assuming that population does not grow at all).

    Dr. Pohl's article simply takes the E.P.A. figures and converts them into a figure which represents the number of extra deaths that one could expect in the long run per 1000 megawatt-years of nuclear electricity produced. The number he comes up with is 396 extra deaths per gigawatt year of nuclear electricity, which is far in excess of the number of deaths usually attributed to an equivalent coal-burning plant. It is worth noting that both the E.P.A. figures and Dr. Pohl's figures are based on the linear hypothesis. If the linear hypothesis underestimates the actual risk by a factor of ten or thereabouts, as argued in this paper, then the actual health effects of uranium tailings may be far worse than anyone has yet reckoned.

  25. See the articles by Morgan and Rotblat mentioned in note 10. See also the Proceedings of the Congressional Seminar on Low Level Ionizing Radiation, reference 1.

  26. Reference 7, page 350.

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