Document nNyjZ73kmwdZXDqR350EgLybR

December 11, 1968 Dr. Samuel S. Epstein Jimmy Fund Building 35 Binney Street Boston, Massachusetts 02115 Dear Doctor Epstein: I think I should inform you as fully as I can at this time.as to the substance, of the paper which I hope to prepare and present in the Symposium in New Yolk next June. At the same time I would like to suggest a modification of the title of my paper, so as to have it conform more fittingly, to what I wish to say. I am prepared to meet your wishes with respject to the discussion of the available literature on the subject of the lead in the ambient air and also to lay the technical (and philosophical) foundation fox' the satisfactory criteria for the establishment of a standard in this .'respect. It may even be possible to propose a standard itself - that is a number indicative of the tolerable concentration of lead in the ambient air. The problem here, however, is not that of defining the toxic level for lead in the air, but father the physiologic level - that is, a level which is within physiologic limits, in the sense that it can.be handled (absorbed and excreted) without measureabie accumulation in the body. This is, to a considerable extent, a matter of semantics, but it is more than that in the realistic sense that the issue here is physiology primarily, rather than toxicology. I would prefer, therefore, to discuss this matter under the title of "Physiologic Appraisal of Lead." This will fit it into the titles of the other papers and, at the same time give it its proper significance. Since this may not appeal to you as being entirely realistic, let me clarify iny tfiew of it. In my opinion, based on many years of efforts to elucidate the behavior of lead in the human organism, the "metabolism" of lead in man is now a fairly well-defined physiologic process, and to discuss it under the heading of toxicology is to perpetuate the error which many ill-informed persons have made. The purpose of a standard for the ambient air is to avoid any toxic effect of the absorption of lead and to keep the population within physiologic limits. With respect to a physiologically tolerable level of the concentration of lead in the air, recent experiments which are the culmination of nine years of investigation, have come within reach of their goal, and I hope to be able to provide the basis for a standard. It will not be possible by January first, to phrase an intelligent resume of what I shall say, since I am just beginning the literature survey and the detailed examination of our data. No abstract that could be formulated at this time would convey any useful information to the reader. I shall first obtain a fair idea of what I shall pi'esent, and then develop the abstract, and finally supply a Dr, Samuel S. Epstein page 2 December 11, 1968 manuscript. I wish to do this at the earliest possible time in order to supply the information which is required to visualise a valid standard, before an official agency proposes something that will, at best, be a guess. Cordially yours. Robert A. Kehoe, M.B. Professor Emeritus of Occupational Medicine RAX:wp P.S. The "abstract text" which I shall forward before January 1, 1969 is merely a statement of the ground that will be covered by the paper. EaK KE 0019676