Document DMJze2z3oDqY7BrM54617pmR5

ffi.'EP- DOW CHEMICAL U.S.A. April 15* 1987 LOUISIANA DIVISION P. O. BOX 180 PLAQUEMINE. LOUISIANA 707M-01BO BOA SSS-8000 1. H. Contacts oo: Mike Nevill, 3502-E Henry Bell, 4701 Dr. Currier, 2303 Lester Poirrier, 4109 Ray Kemp, 4109 1,1,1-TRICBLOROETHANE tox studi The attached telex was recently redyed from Midland. It concerns a recent animal study &hiir'e exposure was to an aerosol rather than a vapor. In the study, rats died at lower' 'level's ( 1375 - 12000 ppm) than in previous studies. the increased Please pass this information along to your plant maintenance people and review any operations in your area where 1,1,1-trichloroethane (Chlorothene*) is used as a fine mist or spray to make sure exposures are being kept below the TLV. William E. Ledford Industrial Hygiene 8b \ N> \N> AN OPERATING UNIT O* THE DOW CHEMICAL COMPANY D0 147707 CONFIOFNTTAl 31 MARCH 1787 ACUTE TOXICITY -- 1*1*1-TRICHLOROETHANE PRELIMINARY RESULTS OF ACUTE INHALATION STUDIES OF AEROSOLIZED 1*1*1-TRICHLOROETHANE* SPONSORED BY THE 3M CORPORATION* HAVE COME TO OUR ATTENTION. THIS INFORMATION HAS BEEN SUBMITTED TO THE U.S. ENVIRONMENTAL PROTECTION AGENCY. RATS WERE EXPOSED FOR 4 HOURS BY INHALATION TO 1 * 11-TRICHLOROETHANE WHICH WAS INTRODUCED INTO THE CHAMBER IN AEROSOL FORM. RATS DIED AT ALL LEVELS TESTED* 7310 TO 63*500 MG/CU* METER. EARLIER STUDIES OF 1*1*1-TRICHLOROETHANE* CARRIED OUT IN A SIMILAR WAY SHOWED LOWER TOXICITY WITH AN LC50 OF ABOUT 76*400 MO/CU. METER. FURTHERMORE* A DOW STUDY OF FULLY VAPORIZED 1 * 11-TRICHLOROETHANE WHERE ANIMALS WERE EXPOSED EVEN LONGER* 7 HOURS* GAVE AN LC50 OF 77*800 MG/CU. METER <14*250 PPM >. IT IS NOT CLEAR WHY THERE IS SO MUCH DIFFERENCE BETWEEN THE MOST RECENT AND THE EARLIER STUDIES. IT MAY BE BECAUSE OF THE WAY THE MATERIAL WAS DISPENSED* LEADING TO HIGHER LEVELS OF AEROSOLIZED DROPLETS OF 11 *1-TRICHLOROETHANE* WE ARE NOT SUGGESTING ANY CHANGES IN WORK PRACTICES AT THIS TIME. HOWEVER* WORK SITUATIONS WEHRE AEROSOLS OF 1 * 1 *1-TRICHLOROETHANE MAY BE ENCOUNTERED SHOULD BE REVIEWED TO ENSURE EXPOSURES TO THE MATERIAL ARE MAINTAINED BELOW THE CURRENT ACGIH TLV OF 350 PPM (1900 MG/CU. METER). ADDITIONAL STUDIES OF 1 * 1 *1-TRICHLOROETHANE TO RESOLVE THESE DIFFERENCES IN APPARENT TOXICITY ARE BEING PLANNED AND CARRIED OUT. YOU WILL BE KEPT INFORMED OF ADDITIONAL INFORMATION AS IT BECOMES AVAILABLE. L. W. RAMPY DIRECTOR* INDUSTRIAL HYGIENE 517/636-6260 J. M. LANHAM CHIEF MEDICAL OFFICER 317/636-210 DOWCHEM C FLAG) DO 142708 C0NFTDFNTTA1.