Document G51vJDgBj37NrN75M6M5vGK3v

THE DOW CHEMICAL COMPANY January 13, 1975 DENNETT BUILDING 2030 DOW CLN1 EH MIDLAND, MICHIGAN 40640 William Gaffey, Ph.D. Tabershaw Cooper Associates 2180 Milvia Street Berkeley, California 94701 Dear Dr. Gaffey: Jerry Ott and I have discussed further the proposal you submitted to MCA December 9, 1974. The following are the three changes that I think we agreed to in principle on the telephone. a. The Union Carbide records for workers terminated before jon. 1, 1945 will be cor11 y cr'ci?.-5n~d be^or" any decision is made to omit them from the study. I have discussed this with Nick Wheeler of Union Carbide and he also feels very strongly that they should be included. It is his understanding that the records given to you will describe the workers exposure in terms of dates on the job at each exposure category. This should allow analysis of data as described in Item C. < b. Data will be examined in terms of type of plant; Vinyl production vs. Polyvinyl chloride polymerization vs. Co-polymer production. It may be that workers will have moved from'one plant to the other so much that this will not be feasible. c. Most important is an analysis in terms of maximum reported exposure concentration. The attached table indicates the cells which Ott and I feel we need estimates. Tables of this type can replace Tables 1, 3 and 4 of'your proposal. This table is an attempt to determine whether the maximum exposure concentrations to which each worker was reported to have been exposed is related to mortality. fr.Afi// RSV 0002177 Dr. William Gar fey -2 January 13, 1975 We appreciate talking to you and await your comments. Theodore R. Torkelson Corporate Medical Department cc: M. G. Ott kjf RSV 0002178 . 'V STANDARDIZED MORTALITY RATI 35 FOR VINYL CHLORIDE WORKERS BY MAXIMUM EXPOSURE INTENSITY*, DURATION OF EXPOSURE, AND YEARS SINCS EXPOSURE BEGAN Interval Since Exposure Started 0-9 Years 10 - 14 Years 15 - 19 Years 20 - 24 Years 30 - Up Years Ye airs of Total Exposure 1-4 years 5 -9 years 10-14 vsars 15-19 years 20-24 years 25 -Up years L* M* H* L* M* . H* L* . M* I H* .. L* M* H* . L* . H* . L* . M L* i -- -- -- -- ! :-- : -- ( L*,M*,H* -- Low, Medium or High based on highest exposure category reported for at least a 12-month period. i ! *