Document p2QGBg4Y01o3KVkdGYJpwp1q7

(conoco) Thom* J. Ch*stf. M.D.. M.P.H. Director Health Information Medical Division December 3, 1987 Conoco Inc. 600 N Dairy Ashford PO Box 2197 Houston. TX 77252 (713)293-4250 Telex 775347 OOEL BENDER, Ph.D., M.D. DEC 7 1987 Jim Vail American Petroleum Institute 1220 L. Street, Northwest Washington, D.C. 20005 Dear Jim: LWA WPJ dor IS tlLE GWL TJC DRY COPY Thank you for your memorandum enclosing the Feasibility Report on the Rotogravure Pressman Study. In general, I would favor going ahead with this study provided the cost is not too high. Naturally, I would assume that API would obtain a more definitive cost estimate with a clear bottom line amount before proceeding. Probably the major item of concern in this feasibility report is the fact that only a four-fold increase in relative risk of leukemia can be detected with an 80% probability. While most government agencies will only recognize a negative study if a relative risk of two could have been detected with 80% probability. In this case, however, this problem does not seem so bad in view of the fact that this study will be matched against the Rinsky Study, which would predict a relative risk of 66.37. Clearly, this study can easily detect such a high relative risk and if a relative risk of that magnitude is not found, the data can be used to refute Rinsky. An issue which is not directly discussed in the paper is the fact that many experts in the field contend that the risk of leukemia from benzene exposure is greater in individuals exposed to high doses for short periods than in individuals exposed to chronic low doses. Given the nature of the exposure of the pressmen, which represents a high-dose exposure over a short period of time, this very important question about benzene toxicity could be answered by the study. T. J. Chester Director Health Information lc: 35 CC: G. W. Love \\CV 000 0149'