Document 3NyRVG12NBXOeyrQRzvKGykLE

bcc: H. Bergen - B2SL W. B. Papageorge - B2SK J. Stapleton - B2SA W. Withers - B2SA December 17, 1974 Mr. Mort Whitney, Manager Product Quality and Safety West Bend Company Vest Bend, Wisconsin 53095 Dear Mr, Whltneyt I apologize for the delay In confirming our telephone dis cussion concerning the acute toxicity of our former fireresistant heat transfer fluid, PR-3. Illness and an un expected trip to Europe have kept me out of the office. As I told you on the telephone, the oral lethal dose of PR-3 in rats was determined to be approximately 11,900 milligrams per kilogram of body weight. For comparison purposes, the Federal Hazardous Substances Labeling Act defines "Highly toxic substances" as those materials with a lethal oral dose in rata of 50 milligrams or less per kilogram, and ''Toxic substances" as those with a lethal dose of between 5o mg/kg and 5<Xi6 mg/kg. We do not have a lethal dose In animals as a result of Inhala tion of vapors but from Infrequent mishaps during manufacture, we conclude that man would not Inhale voluntarily enough vapors to result In serious Illness. The vapors are Irritating to the eyas and respiratory tract at levels which serve to limit ex posure of any consequence. You mentioned that you had replaced FR-3 with our THERMXNDL 66. You may be Interested In learning that the oral lethal dose In rats of this material Is approximately 10,200 ollllgrams/kg. Within the limits of toxicological significance at such dosage levels, this number Is comparable to the dose previously cited. May I take this opportunity to wish you a very Merry Christmas HUNS 09516Z Mr. Mort Whitney December 17, 1974 Page - 2 - and a Happy Holiday Season. - Very truly yours. /bkp ELmer P. Wheeler Director, Environmental Health HONS 095163