Document NNBK27QgGYyr3Y0ryq26BxXyV

November 20, 1962 Mr. Charles L, Cheever Argonne National Laboratory 9700 South Casa Avenue Argonne, Illinois Dear Mr. Cheever: Thermlnol FR 1, 2, 3 heat transfer fluids referred to in your letter of November 13, 1962 are chlorinated biphenyls. They are more refined forma of our Aroclors 1242, 1248 and 1254. These compounds are biphenyls, chlorinated to 42, 48 and 54 respectively. There are enclosed three pieces of literature describing these liquids which I think will answer your questions. Specifically, the potential fire hazard is not great since the advantage in using these fluldB is that they are resistant. Health hazards are minimal except when the fluids are heated in open vessels or containers. We feel that in any application where temperatures exceed 150F, fluids must be used in a closed system or adequate exhaust ventilation oust be provided. I believe you will find the vapor pressure data in the enclosures serve as a basis of this recommendation. We do not believe protective clothing la necessary to prevent skin contact during transfer of these fluids. They are not akin irritants in the usual sense of the word. They are excellent solvents and will dissolve the normal oils and fats of the skin possibly leading to drying and chapping if exposure is prolonged or repeated. Although the fluids may be absorbed through the skin with resulting systemic effects, this is not a serious hazard unless again, exposure is prolonged and repeated, we feel there is no significant absorption from acute single expo sures. Obviously, if workmen spill a Thermlnol fluid on the hands, it should be removed by washing. Similarly, grossly contaminated clothing should not be worn without laundering. In experiments where suitable animals were exposed to the decom position products of such fluids, toxic effeots occurred in the animals only at concentrations which Humana would not voluntarily endure because of irritation to the eyes and respiratory tract. The chief decomposition products are hydrochloric aeld, carbon COMPANY CONFIDENTIAL TRAN 019568 WATER PCB-SD0000004723 Hr. Charles L. Chevp - Pag 2 - November to, 1962 monoxide, carbon dioxide, phenolica and aldehydes, in the studies oonduoted for us by Kettering Laboratories, fluid ni allowed to drop onto inoonel surfaeee heated to 1050 and 1250?, There is essentially no decomposition below 600F. In our experience, expoaure to these fluids in heated transfer systems has resulted only when the system has been improperly installed. For example, some initial installations have net carried che vent line from the surge tank to the outdoors but have vented vapors of ths fluid to workroom areas. In boom initial installations, the piping that was used had threaded Joints whereas we reeacstaend & system less subject to leaks. Such practices may allow chronle exposure to vapors which must be avoided. In the history of the use of these fluids, there have been Instances when the fluid has been sprayed into open flames or - in the case where the fluids are uaed as hydraulie fluids - line ruptures have caused the fluid to be sprayed on molten metal. Fires have never occurred under these circumstances. Depending on the amount of fluid involved and the temperatures, the working environment becomes filled with elouds of smoke and vapors such that the area must be vacated. Workmen have always had the opportunity, however, to stay in the area long enough to shut down operations without suffering serious toxic effects. If I can be of any further assistance, please do not hesitate to let me know. Very truly yours. JTO+af Enclosures Jack T. Oarrett Industrial Hygienist Medical Department COMPANY CONFIDENTIAL TRAN Oi9569 WATER PCB-SD0000004724