Letter to W H Langham, Subject: re Standards for Plutonium

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CASE WESTERN RESERVE UNIVERSITY CLEVELAND.OHIO4.1106 LOS Alamos Scientific Laboratory LOS Alamos, New Mexico 87544 Iam finally getting around to replying to your letter with regard to the early history of the establishment of standards for plutonium. You may not know that about two years ago I was enticed by John Totter and Alex Hollander t o prepare a history of the research activities of the Manhattan Project during its Menhattan District days -- in effect,to July, 1946. Therefore, I have had access toa number of documents a t Oak Ridge, a t Chicago, atthe University of California, and some from Los Alamos. The history of the examination of alpha emitter hazards atthe Manhattan Project was begun very early. Dr. E. 0. Wollan made a calculation assessing the energy transfer from internally distributed emitters (he used radium asa prototype) compared with the dose from external radiation. However, specific mention of plutonium does not occur until fairly late. It may be that this was due to the fact that plutonium was thena very closely guarded secret, and was not identified in written biological reports until late in 1943 or early in 1944. the first contact with plutonium a8 a hazard was that early in 1944 we simply considered the energy available from plutonium disintegration and compared it tothe energy available from radium, assuming approximetely the same distribution. A s you know, the standards for radium at that time were 0.1 microcurie (or microgram) for whole body deposition and the calculations show that about 50 times aa much energy le available from radium a8 compared t o plutonium, mass Asa matter of fact,in August of 1942 My recollection of I n October, 1944, there is a rather extensive report by J oe Hamilton who wee app8r cnt ly given the responsibility for making some assessment of the distribution of pluto nim.He indicates in this report that he received the plutonium i n February, 1944, so that obviously during the end of 1943, exami nation of the question of the hazards of plutonium were being considered. There are extensive tables showing the dl atri but ion in animals, and undoubtedly somewhere in the official write-up ofthe plutonium project by Bob Stone there may indeed be reference to this original work. look through the official plutonium project publication and perhaps more direct I would suggest that you information might be available.

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For your information, the responsibility for the biologica 1significance of pluto nim deposition in the body -- that is, metabolism, excretion, environmental assay, etc. -- was under the general direction of the MET laboratory. The MET Lab at first asked Dr. Hamilton to carry Out the primary studies with regard to distribution and over - all metabolism, but later extensive work was carried on by K. C. Cole and his associates, and others, there are periodic reports issued by the MET Lab during 1944 concerning health problems relating to "product" asthe plutonium was referred to colloquially. It is not until 1945 that reports began t o appear regularly about the metabolism of plutonium and about questions of hazard. identification of the tolerance level is present in specific reports,but there is continual reference to the fact that the body burden was considered t o be 5 micrograms of plutonium, and your general outline is correct in this analysis. It is interesting that As far as I know, no clear - cut All through 1945 there is description of various mechanisms for this time there is also discussion of methods of analyzing excreta from patients t o determine something about body retention. several places,but there are extensive reports in Chicago of the various approaches to this. This undoubtedly was going on i n Atthe end of 1945 my contact with this began t o diminish since I left the AEC i n June, 1946, and my concern with the question of plutonium hazard and tolerance then became sharply limited. I hope this is helpful to you. Perhaps a t some appropriate time more direct and extensive verbal comuni cation might be helpful. My very best regards. Pr f essr of Radiology