ATTACHMENT 6 B&M 1019 Dr. S.E. Miller, Chief, Div. Occupational Health, BSS Through: Dr. Seller, Director NCI NC-RB-BP Dr. Sebrell, Director, NIH March 12, 1952 Dr. Scheele, Surgeon General Dr. Lorenz, Chief, Laboratory of Biophysics, NCI Interim Report of a Health Study of the Uranium Mines and Mills It is evident that there is a considerable health hazard associated with the mining and milling of uranium. However, more data will be needed than is supplied in this report before the whole problem can be evaluated properly. The recommendations contained in this report -- proper ventilation of the mines and wet drilling -- represent the initial prevention measures which should be instituted. There are a considerable number of mines, some of which are apparently in very isolated areas, where sufficient power may not be available to carry out proper ventilation and wet drilling. Because there is still no agreement as to the permissible dose of radon in equilibrium with its short-lived decay products, it may be advisable to consider very extensive mine surveys and, possibly, cessation of operations until such facilities become available in these areas. The important role which the production of uranium plays in the national welfare is apparent. Also apparent is the responsibility of the Public Health Service, not only in the field of industrial health but also in instituting fundamental research to satisfy a pressing need for basic information dealing with the biological efforts of radon. As a first step I should like to propose that a small group of scientists who are familiar with the subject be assembled to meet with Public Health Service representative for an informal discussion of the problem. The Atomic Energy Commission will cooperate in such a discussion and will Dr. Robley Evans, Dr. Austin Brues and his group at the Argonne National Laboratory. Dr. Robley Evans of M.I.T. will be contacted when plans for such a discussion have been established. One of the major interests of the Laboratory of Biophysics, NCI, is the carcinogenic effect of ionizing radiation and its effect on life span in experimental animals. In the light of some of the experimental findings the following remarks are made to aid in evaluation of some of the statements contained in the interim report CONFIRMED TO BE UNCLASSIFIED BY AUTHORITY OF DOE/OC Wilbur A. Straused 11-12-80 REVIEWED BY DATE By: Dick Koogle 6-4-87 US DOE ARCHIVES RG 326 U.S. ATOMIC ENERGY COMMISSION Section DBM Box 3353 Folder 33 19786 2 Dr. Miller Through: Dr. Heller, Dr. Sebrell, Dr. Scheele March 12, 1952 The chapter dealing with experience in European mines state, "In view of our present knowledge most authorities have concluded that these cancers were due to exposure to radon and its decay products." This statement confuses the issues. A careful review of the literature reveals that the opinion that radon is the sole case of lung cancer of the miners cannot be maintained (E. Lorenz, Radioactivity and Lung Cancer. J. Nat. Cancer Inst. 5,1- 15, 1944). Furthermore, it has been shown that chronic irradiation is only weakly carcinogenic in mice with a high spontaneous incidence of spontaneous lung tumors (E. Lorenz, et al., Increase in Incidence of Lung Tumors in Strain A Mice Following Long Continued Irradiation with Gamma Rays, J. Nat. Cancer Inst. 6, 349-356, 1946). This is mentioned here only to show that categorical statements as the one mentioned above have little foundation. They are not intended to minimize other hazards connected with exposure to radon and its short-lived decay products, e.g. shortening of life span, premature aging, etc., but to point out that considerable research has to be done yet to evaluate the role of the carcinogenic which also may contribute or may be the sole cause of carcinogenesis. It has been found that metals such as chromium and cobalt are carcinogenic (Schins, H.R. and Uehlinger, E., Der Metal Krebs. Ztschr. f. Krebsforschung, 52, 425-437, 1942); recently Husper (J. Nat. Cancer Inst., In press) has shown that uranium induces tumors. Vanadium which is found in the mines may also prove to be carcinogenic as well as other non-radioactive metals. As far as the chapters on radon and its decay products and their measurements are concerned, I disagree with many statements made. It is realized that it is extremely difficult to obtain accurate measurements of activities in the mines and it seems to me that the data cited give only the qualitative statement that the radioactivity is high, but no more. I do not see any reason for introducing a permissible dose for RaA and RaC1. While it is true that practically all decay products of radon may be absorbed on dust, some radon will be absorbed also on dust and decay during the time of sampling on the filter paper. The sampling maya be complicated further by the possibility that very fine dust particles (<0.5u) are not retained by the filter paper. (It was found in this laboratory that radon and its decay products penetrate rubber gloves). Therefore, the value obtained on the filter paper, as stated before, will be indicative only of the fact that radon and 3 Dr. Miller Through: Dr. Heller, Dr. Sebrell, Dr. Scheele March 12, 1952 fact that radon and its decay products are present. In the ideal case the radon in the mines will be in equilibrium with its short-lived decay products. Therefore, a permissible dose for radon should be established in equilibrium with its decay products. Methods are available (absorption on charcoal; see J. Hollcroft and E. Lorenz, The Retention of Radon by the Mouse, Nucleonics, 5, 63-71, 1949) to establish accurately the radon content of the air in the mines. With this content measured the amount of the decay products in equilibrium are known. Let us consider the fate of radon and its decay products following inhalation. It is known that the smaller the dust particle the less its chance to be retained in the lung (e.g. Shaw and Owens, The Smoke Problem of Great Cities, London, Constable & Co., Ltd., exhaled. The larger ones will settle in the bronchi and alveolar spaces. Radon gas will be absorbed by the blood until equilibrium is reached, and after a few hours there will also be equilibrium between radon and its short-lived decay products in the body. This is the ideal case; in reality the decay products tend to accumulate in certain organs, notably in the kidneys (J. Hollcroft and e. Lorenz, The 30 day LD-50 of Two Radiations of Different Ion Density, J.Nat. Cancer Inst., in 12, 533-544, 1951). No accumulation above the average will take place in the lungs. However, the possibility exists that inhaled radioactive dust may be retained in lung tissue. However, the possibility exists that inhaled radioactive dust may be retained in lung tissue, thus increasing the dose to lung tissue. No data are available to indicate the amount retained. In any case damage to kidneys may be more important than to lung tissues, especially as it has now been shown that large doses of chronic gamma radiation have a low carcinogenic potency as far as lung tissue of susceptible mice is concerned. It may be argued that alpha irradiation produces greater biologic effects than gamma radiation for equal amounts of absorbed energy. Such a statement does not seem to hold in the acute stage of irradiation injury, however, for animals, as shown in the above paper. It was found that the 30 day LD-50 was approximately the same for X-radiation and alpha radiation. In conclusion I want to state that according to available evidence the danger of inducing lung tumors in humans by chronic inhalation of radon, although possible, may not be as important as other factors, such as shortening of the life span and the effects of chronic inhalation DOE ARCHIVES 4 Dr. Miller Through: Dr. Heller, Dr. Sebrell, Dr. Scheele March 12, 1952 of are containing metals such as vanadium and uranium. Nevertheless, an exhaustive study of the radon content of the mines should be made as previously outlined. In addition, studies should be made on miners on the radon content of exhaled air when leaving the mines by the above mentioned charcoal method, supplemented, if at all feasible, with measurements of gamma radiation by crystal counters especially over the area of lungs and kidneys. A comprehensive experimental study of the effects of radon on carcinogenesis and life span should be made. The recommendations made in the interim report with regard to ventilation of mines, etc., together with periodic health checks seem adequate. As mentioned at the beginning the data of the interim report are too scant to give a proper evaluation. In a discussion held in the N.C.I. March 12, 1952 with Drs. Howland, Bale, Hodges, and Blair from Rochester on this problem, it was brought out that considerable additional information is available in the New York Operational Office of the A.E.C. In order to gather all existing information and arrive at some definite proposal, it is urged that a small informal conference, as heretofore mentioned, be held as soon as possible. cc: Dr. Charles Dunham, AEC Dr. Austin Brues, Argonne National Laboratory Dr. Howard Andrews, NIH Mr. C.V. Kidd, Research Planning Branch, NIH