Document Jr7N0mZ37key3xodyrkGDvaLB

INFORMATION COPY > DOW CHEMICAL U.S.A. August 17, 1973 POST OFFICE BOX 1706 MIDLAND. MICHIGAN 48640 Mr. A. C. Clark V.P., Technical Director Manufacturing Chemists Association 1825 Connecticut Avenue, N.W. Washington, D.C. Dear Mr. Clark: As discussed on the telephone with you and Mr. Slatin, we are sorry for the delay in starting the experiment, but the Vinyl Research Coordinators consider the restarting of the Industrial Bio-Test study as an opportunity to review our exposure concentrations. At the suggestion of Howard Kusnetz, the Research Coordinators have been polled and have agreed that the Technical Task Group should be quickly contacted and appraised of the possibility of lowering the exposure concen trations . The concentrations of 5,000 ppm, 500 ppm and 50 ppm currently being used at Industrial Bio-Test were selected many months ago. While there are good reasons to continue with these three exposure levels, there are also good reasons to lower the levels to 2,500 ppm, 200 ppm and 50 ppm as suggested by Howard Kusnetz. 1. 2,500 ppm is high enough that the results should be positive if our results agree with the European data. 2. 200 ppm is the current ACGIH TLV. The European data were apparently positive at 250 ppm and rats are now being exposed to 100 ppm by Dr. Maltoni. This being the case, the no-effect level could be between 250 and 100 ppm, and a group at 200 ppm could be useful. 3. 50 ppm -- It doesn't appear reasonable to go below this level unless we redesign the study completely and increase the size of the group. I'm going to be out of town until August 27. Would you contact the Technical Representatives and ask for a very rapid response to Kusnetz' suggestion? If they have any questions before August 27, they can call Howard at 713-220-5604 or they can wait till I get back and call me at 517-636-5197. AN OPERATING UNIT OF THE DOW CHEMICAL COMPANY DTH 000013665 INFORMATION COPY Mr. A. C. Clark 2- - August 17, 1973 It is essential that they respond immediately since we need to notify Bio-Test by September 1. Sincerely yours, T. R. Torkelson Registration Section Ag-Organics Department nc cc: Harry Slatin, MCA Howard Kusnetz, Shell Oil Co. DTH 000013666