Document pmByxg3v4L0yjoZjzYVrX1GLw

Ba l t imo r e Cit y Ho s p it a l s Fr e d e r ic G. Hu b b a r d d ir ec t o r 4940 EASTERN AVENUE BALTIMORE, MARYLAND 21224 March 31, 1 971 DEPARTMENT OF PEDIATRICS Ha r o l d E. Ha r r is o n , M.D. PEDIATRICIAN-IN-CHIEF Dr. Robert A. Kehoe Professor Emeritus of Occupational Medicine University of Cincinnati Kettering Laboratory Department of Environmental Health Cincinnati, Ohio 45219 Dear Dr. Kehoe: Many thanks for your very kind letter of March 15. I too regret that our past corres pondence has lapsed somewhat. I want to thank you for your verylcind remarks about my efforts on the lead panel for the National Academy of Sciences. I suspect my current views are reason ably clear from that contribution. I have be4n struggling for at least the past nine months to reach some conclusions as to where the reaj risk lies and how one can be reasonable about this problem. I believe that the evidence supports the concept that blood lead levels <40 pg Pb % are associated with no risk to health whatever, that the 40 to <S0 pg Pb range is a slightly gray zone and that the risk of adverse health effects begins to rise significantly as blood lead levels rise above 60 pg Pb/100 G whole blood. Obviously, much remains to be done to determine whether this is an accurate view of the situation. Clearly, industrial lead workers and youngchildren in urban areas are the ones at risk today. We have been doing blood lead levels, chela tion tests and quantitative urinary ALA determinations in children during the past year whose blood lead levels lie between 25 and 80 pg Pb %. Unfortunately, no children with lower blood levels were available for that study. I am about to prepare this for publication and will be glad to supply you with a manuscript when It ?s completed. Some of the pertinent data will be included in the lead panel report. In conclusion, I might say that it is easy to take an extreme view at either end of the spectrum. To me, the difficulty is in finding the middle ground and defining the risk from the scientific basis. However, if it is difficult, it makes it interesting and worthwhile, so I shall pursue the problem. 1 Yours sincerely. JJC:ov N22119