Document GKmML4YNbrgbZ7bzpvQ33grGv

May 22, 1967 John R. Goldsmith, M.D., Chief Environmental Hazards Evaluation Unit Department of Public Health State of California 2151 Berkeley Way Berkeley, California 94704 , . Dear John: ~ I am pleased by your reply to jay letter of March 22, although it will be no surprise to you to know that I do not agree with it entirely. I do agree with your attitude of objectivity, and I respect your manner of approach to the problem with which we are concerned. I take the general position that if the available data which are under consideration are not entirely convincing to you, they will not serve to resolve the issues conclusively, and that we shall have to have better evidence or evidence better presented. I shall not undertake here to argue with you about details either of fact or of procedure. If either of these aspects of the matter is lacking in acceptability, the need for more information is apparent. On only one matter which you raised do X feel it required of me to respond - namely, extent of the retention of lead in the human body under variable circumstances: The investigations which we have carried out here do not answer this matter conclusively, whether they have been concerned with "balance" experiments in the intact human subject, or with the actual determinations of the lead in the tissue of human cadavers. Xn neither instance is it possible to obtain direct information concerning the effect, in this respect, of a determinable set of environmental conditions. The error of observation and of inference may be, and I believe it to be; small, but it is not determinable with certainty at present, and thus there is a gap in our information that must be bridged for the reason that time, i.e., a lifetime, can give significance to a small error. This is the reason that X have concentrated so pointedly on the development of a reliable means, tha,t is a means soundly based in physiology, for determining the body burden of lead in the intact human organism. There are ways, I believe, by which this can be done. The counterpart of this requirement is that of determining the actual extent of the absorption of lead from the respiratory tract under a variety of conditions. X am looking into an experimental method of accomplishing this result under a single well-controlled set of conditions. In short, in my view; the answers which will satisfy mejl, and you as well, will have to be obtained by observation, and not by calculations of any kind based upon inferential procedures * With kindest regards, Sincerely yours, RAX:wp P.S. X just received the report and will Robert A. Kehoe, M.D. Professor Emeritus of Occupational Medicine N5952