Document wq3nBoyq6KRLexK6w9qD1mpXQ

c 0 P y . ESSO ;LABORATORIES' Standard Oil Development Company Medical Research Division Robert E. Eckardt, Ph.D.,M.D. Director N. V. Hendricks, B.S., Ch.E. Director, Industrial Hygiene Section Franklin W. Church, B.S., (Ch.E.) Industrial Hygienist P. 0. Box 51 Linden, N. J. Mr. Jacob Cholak Kettering Laboratory of Applied Physiology University of Cincinnati Eden Ave. . Cincinnati, Ohio Dear Mr. Cholak; In cooperation with Mr. J. W. Hammond of the Humble Oil and Refining Company, we are attempting to develop semi-quantitative coproporphyrin standards which would be useful in the medical departments of affiliated companies, in order to develop some additional information on a urinary coproporphyrin excretion in employees ex posed to lead and who are now receiving periodic urinary lead examinations. Mr, Hammond suggested to me that you might have a copy of the paper which you presented at the 1952 Industrial Health Conference in Cincinnati and might also wish to make some comments concerning the preparation and utility of"such standards. Mr. Hammond has been kind enough to send me a sample of coproporphyrin, type 1, which he had obtained from Dr. Watson of Minnesota and it.is our plan to try and make up from this sample a series of standards which would be graded as 0, 1+, 2+, 5+ and coproporphyrin to assist those in affiliated medical departments in evaluating the coproporphypin content of the urine samples which they are analyzing. I would greatly appreciate any thoughts and ideas which you may have on the preparation of such standards and their stability. Very truly yours, REE/hml cc: M r . J.W. Hammond S/R. E. ECKARDT, M.D.