Document x1VXgo73KbExk0N1bGjYg1wZ1

Ba l t im o r e C it y Ho s p it a l s Fr ed er ic G. Hubba r d dir ec t or 4940 EASTERN AVENUE BA LT I M O RE, M A RYLA N D 2 1 2 2 4 March 311 1971 DEPARTMENT OF PEDIATRICS Ha r ol d E. Ha r r iso n . M.D. PEDIATRICIANIN*CHIEF Dr. Robert A . Kehoe Professor Emeritus of Occupational M edicine University of Cincinnat i Kettering Laboratory Department of Environmental Health Cincinnat i, Ohio 45219 Dear Dr. Kehoe: M any thanks for your very kind letter of M arch 15. I too regret that our past corres pondence has lapsed somewhat. I want to thank you for your very "kind remarks about my efforts on the lead panel for the N ational Academy of Sciences. I suspect my current views are reason ably clear from that contribution. I have behn 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 (SO 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 determ ine whether this is an accurat e 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 availab le for that study. I am about to prepare this for publication and w ill be glad to supply you with a manuscript when it is completed. Some of the pertinent data w ill 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 diff icult y is in finding the middle ground and defining the risk from the scient if ic basis. However, if it is dif f icult , it makes it interesting and worthwhile, so I shall pursue the problem. 1 Yours sincerely, JJC:o v / J./ ju l i a n Chisolm, Jr . , M . D. N22119 I 03870