Document 3Ngyw5gYo98oaKJjd5M7XaeD0

F e b r u a r y 16, 19 6 7 Ken Nelson, Director Department of Hygiene American Smelting and Refining Comoany 3422 South, 700 West Salt Lake City, Utah 84119 i. Dear Ken: * '. ' I- I am pleaded to have your letter of January 30, and also to answer your questions about the significance of the critical concentration of lead in the blood in relation to the danger of intoxication. First, lejfc me say that the transcript of my testimony in Harrisburg was indeejl ''rough". I have sent in an edited copy which may or may not replace the stenotypist's version, dependent upon the official policies in such matters. I am not sure how far my. testimony achieved its purpose, but I sent in a fuller statement, as requested, for such use as the Commission may choose to make of it. I hope it will be added to the public record. I am reasonably sure that the Commission will not dopt a level below 12 micrograms of lead per cubic meter, as a "tentative standard" for the ambient air. , vrith resp ect to your query, the answer is in the affirmative. We have seen case s of lead poisoning of mild but definite character when the concentra tion of lead in the blood, by our methods of analysis, was at the level of 80 micrograms per 100 grams of whole blood. No method of analys is with which I a m familiar is capable of yielding this figure with an a ccuracy that is greater than plus or minus 10 micrograms N 6128 February lb, i j b' J (when the samples analysed are of the usual weight of 10 grams). do duplicate analyses, as a rule, however, In the investigation of the blood , so that we improve the precision somewhat thereby. 'e have not publi shed case reports in thi3 relationship. In fact, I rarely publish r eports of individual cases unless there is sme very unusual situt ion that justifies it. The many cases of lead poisoning in which we have been involved, in one way or another, during the past twenty-fi ve years, in which we have employed essentially the same nethods o f analyses, would hardly justify individual publication for any reaso^i let me point out that I do not now, and never have, talked about poisoning and the alkyl lead compounds, in this connection, except to point out that the anlysis of the blood Is valueless in these case3. These cass show very little change in the concentration of lead in their blojod, even in association with fatal intoxication. That, of course is a different story. The compounds that result from the intermediate metabolism of these compounds behave differently than the inorganic compounds. However, we have investigated the status of thousandSj of workmen in a very large number of lead trades, over the years, injacting as the consultants and monitors of 3uch industries, and it isj of these that I have spoken, in a series of publications, from the poing of view of the application of analytical services in industria 1 hygiene. You will realize of course, that I am no analyst, and and that }C usually talk about "our" work, meaning the analytical work of Cholak and his group, in coordination with the clinical and medical viork of myself and a series of associated in our clinical group. In many instances, we have followed large and small groups of 3 February 16, 1967 employees at intervals, year after year, In conjunction with environmental investigations (sometimes of our dwn doing) and al3o medical and employment information on the personnel. Therefore, we have, I believe, the largest bulk of coordinated information that is available anywhere. (In addition, we have consulted with local and some distant colleagues, in their handling of childhood problems of lead exposjure and lead poisoning for the past thirj# years, and 'nave followed, |Ln this way, a large number of cases (several hundred) during that period many of them at the onset of their acute episodes of illness, ^he record, therefore Is fairly complete. I hope, some day, to have an(opportunity to assemble and classify these data forpublication, in relation to a number of important hygienic and clinical ii considerations.) There is, then, no doubt, about the fact as stated above. :e have seen ouch cases occasionally, as well as many at slightly higher levels i.e. 10 to 15 micrggraras per 100 grams. This brings me to your other point - namely, that many persons have reached levpls well above 80 micrograms per 100 grams of whole blood without illness. This i3 certainly tiare. Indeed it is true that no level of th concentration, of lead in the body of an individual, or in any tissue, with the possible exception of that in the brain (of this I cannot be sure, from our data), or in any body fluid, including the urine, is indicative, in and of itself, of lead intoxication. We have seen personsj with levels beyond 500 micrograms of lead per 100 grams of blood, who h^d none of the symptoms or signs of lead poisoning. I have stated ^his fact again and again for years, but it seems not to have made anjr impression on most people, Including physicians. Many - 6002019 4 February lo, 19 6 7 insist on arriving at a diagnosis of lead poisoning by means of single analytical finding. I have said, until it has become trite, that 'the diagnosis jof lead poisoning must always be made on the clinical grounds of finding symptoms, or signs, or both, that are compatible with our knowledge jof the toxic effects of lead. The analytical findings merely demonstrate that the extent of the absorption of lead, as shown by appropriate analyses, is compatible or incompatible with the diagnosis of lead poisoning, that is, they can exclude but not prove. From the aspect of industrial hygiene, the determination of the extent of the absorption of lead by individuals and occupational groups, differentiates between safe and dangerous environmental conditions *I (not ail ofj which relate to occupational exposure but can be identified by approprit investigation, as a rule.) kith respect to the high values, there are, so far as I can see, two methods of tj;heir prevention and control. The best, of course, is the elimination'of dangerous environmental conditions, whether in industry or elsewhere}. There are some Industrial operations that are extremely difficult arid costly to control. 1 cannot see that co3t sha&ld be permitted to be a factor in these, unless there is an operation that is unusual, temporary, occasional, or is of such a sort a3 to affect only a very few people. In the latter situation, extraordinary means of individual protection are Justified, including shortening their 1 periods of eiposure, as well as alternating periods of employment involving no exposure, with those of exposure. I have had good reason to believe, however, that the cost of cei'taln types of control, in, 0002020 5 February 16, 13 6 7 irresponsible as well as highly competitive industries, has often prevented their use, and that workmen have been victimized by this unciviliz ed situation. An attitude of mind has developed in those who direct certain industries, to my certain knowledge, that it costs too much to provide complete safety from exposure to lead; that the disease is not very serious, in the main, and that one can justify jhe occurrence of a case or two now and then. I have never been able to accept this view. I do not believe that a process or a product that takep its toll of human breath or life should be permitted to continue.! If it cannot be controlled, and if it continues, It is a social liability, and should be abolished. This is hard doctrine, but it Is: the only acceptable doctrine, I believe, for the guidance of the professional technical or medical industrial hygienist. One last point, that is, on the establishment of criteria by a medical or scientific organization - for medical-legal purposes - some effort is made to achieve this result, by the democratic and educational process, but there is no such authority that can lay down and edibt of this sort and make it stick. Actually, only a relatively small group of persons in the American Medical Association has had the experience and acquired the knowledge, that would justify any such action, in our jurisprudence, the knowledgeable persons are often called upon to appear in courts or legal and offteal hearings of one kind or another, and give expert testimony. Such persons al3o p8blish their findings, for the benefit of their colleagues and the community. My chapter in the last edition of Patty et al., is an example of this sort. This chapter has in it the 'methods (and their scientific and 6 February 16, 19 6 7 social justification) that we have found to be wholly satisfactory for the purpose. These combined activities are about all, I believe, that vie are prepared to accept in our society as means of declining the'e issues. In the long run - and I realise that it is often a very long run - this is probably the best way of handling these matters. ; In the medical and hygienic literature of our time, an i _ intelligent technical industrial hygienist, as well as a reasonably sensible physician, can find ail of the Information he needs to steer a judicious course in this field. It is true, of course, that one must set |about to learn where reliable sources of information can be found, but this is not too difficult. The trouble is that the physicians t generally, know so little, from experience and study, about head 1 ooisoniny, and the disease has been known to be among us for so long, that they do not understand how little they know. They actually believe phat they know something about it, although they have had little or no experience, and have not kept up with the knowledge that j* Ls available. The old' saws that came to their attention in their student days are just about all that many of them know about It. .And yet,! a physician with a license to practice medicine is regarded as an exjpert, in courts of law and in industrial compensation circles, quite asj'rauch of an expert, in fact, as is a man who has spent much of hl3 life in observation, study and research. (I think, from what I have heard, that this is somewhat less the case In your State of Utah, thjan it is in many others). Here is where we need some integrity and intelligence among attorneys, and judges, and until we have satisfied that need to a greater extent than is now apparent, we shall he in trouble. :' 1 " " * 7 F e b r u a r y 16, 19 6 7 But enough, I had no intention of writing at this length when I started, but having been traumatized considerably, lately, by certain of these matters, I tend to react at times with vigor. Let me thank! you again for your letter, and accept from me my kindest regards. . Sincerely yours, Robert A. Kehoe. M.D. __ -- =sTN---A S^ CO K. W . N E L S O N A M ERI CA N SM ELT I N G A N D R EF I N I N G CO M PA N Y ! D EPA RT M EN T O F H Y G I EN E ; 3 4 2 2 SO U T H - 7 0 0 W EST , SALT LA KE CI TY, UTAH 84119 i January 30, 19 6 7 Dr. Robert A. Kehoe Kettering Laboratory College of Medicine j Cincinnati,- Ohio 45219 i Dear Dr. Kehoe: I I've just been reading the rough transcript of your testimony on lead before the Pennsylvania Air Pollution Commission. Please accept my sincere thanks for straightening out the Com ; mission's thinking on lead. | Your point about individual susceptibility to inhaled lead interested me very much. We have ; learned that we too often ascribe to individual susceptibility marked differences in lead ab ; sorption among men ostensibly having the same exposure. But almost always, If we observe closely ! the working habits of each man, we find that true exposures are markedly different. I believe I have read all your published work on I lead. Yet I have not found, or at least I do not recall seeing, a report of a clear-cut case of ; clinical lead poisoning accompanied, at the onset of symptoms, by a blood-lead as low,as 80 micrograms i per 100 grams. Have there been such cases? Over the years we have found many blood-leads above 80 and some as high as 300 without definite illness. Our exposures of course are to inorganic lead only. lj)r. Robert A. Kehoe We are not happy when we find high blood-lead values and we do what we can to bring them down. Rut this is difficult in some instances because there is no illness, and men object to changing things when a laboratory result is the only reason for change. Another difficulty is that compensation courts almost automatically declare any blood-lead level above 80 is lead poisoning. Wouldn't it be well if a set of diagnostic criteria were set by the AMA or some one, so that these compensation cases could be decided fairly? With very best wishes, KWN/mb 0002025