Document bBqwmrqwOnvMzkgp8kvqnO6oy

REPRODUCED AT THE NATIONAL ARCHIVES Ootober 16, 1924. Md/sJD Mr. E. S . Frggu,-- SOIOTTMO A U E R ' ^ ^ ^ i ^ | i ^ f r ! f 0VT'''forfc. SUBJECTi Tetra-ethyl gasoline Dear Mr. Free v-; Tour le t t e r to Dr. Bain, who is away from Washington, has been referred, to me for reply. The Bureau of Mines has beon carrying out some studies to determine the possible to x ic ity of exhaust gases from an engine using gasoline containing tetra-eth yl lead. We have exposed many animals, including rab b its, guinea p ig s , pigeons, dogs, and monkeys, to the exhaust gas diluted with a ir Just su ffic ie n tly to prevent acute e ffe o ts from carbon monoxide, that i s , so that the a ir would contain from 0.01 to 0.03 per cent of oarbon monoxide. The animals have been exposed in two groups, one group being exposed three hours d a lly and the other s ix hours d a ily . These experiments have been running for about ten months with no symptoms of lead poisoning in any animal. Reoently we have increased the amount of tetra-eth yl lead in the gasoline to fiv e times the amount now rooommended for use in automobiles. This teat has been running for some weeks without any apparent e ffe c ts . We Intend to lnoroase the oonoentratlon of the tetra-ethyl lead in the gasoline to a point where Bymptoms of le a l poisoning are obtained, i f they are not abtained from the above. During the experiments, animals have oooasionally been k ille d to bed. examined for load. Ho lead has been found in th eir bodies up to the present time; none has been k ille d since the higher concentration has been used, so we do not know what w ill be the find in gs. As the study is s t i l l in progress, we do not care to draw d efin ite oonolusiona and i t is requested that none of the above be published. However, there havsbeen many inquiries and demand for published statement of our findings and i t may seem advisable a l i t t l e la te r to get out a preliminary one. If th is i s done, a oopy w ill be sent to you. \v REPRODUCED AT THE NATIONAL ARCHIVES --2-- We are intending to carry out further stu d ies covering the p o s s ib ility of poisoning from tetra-eth yl lead from nay source that would a ffe c t the publio. Of course, such stu dies take time and any statement at present would he a mere guess. Toura very tru ly . R. R. SAYERS Chief surgeon, U .S.B.of U. Surgeon, U.S.P.H.S. /