Document NGqyQ0DKQY9qxqKz3MLrDR1vg

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 forms of our Aroclors 1242, 1240 and 1254. These compounds are biphenyls, chlorinated to 42, 48 and 54 respectively. There are enclosed three pieces of literature describing these liquids which X think will answer your questions. Specifically, the potential fire hazard la not great since the advantage in using these fluids 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 Bystem or adequate exhaust ventilation must 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. Thoy are not skin 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 effects occurred in the animals only at concentrations which humans would not voluntarily endure because of Irritation to the eyeB and respiratory tract. The chief decomposition products are hydrochloric acid, carbon MONS 090355 Nr. Chari* L. Ch**v*r - Pag* 2 - November 20, 1962 monoxide, carbon dioxide, phenolioa and aldehydes. in the tudl** oonduoted for ua by K*tt*rlng Laboratories, fluid was allowed to drop onto lnooml aurfaeaa heated to 1050 and 1250F. There Is essentially no deaompositlon below 600P. in our experience, exposure to those fluids in heated transfer systema has resulted only when the system has been lnproperly Installed. For exaaple, bom Initial installations have not carried the vent line fron the surge tanlc to the outdoors but have vented vapors of the fluid to workroom areas, in some Initial Installations, the piping that was used had threaded Joints whereas we recommend a system less subject to leaks. Such practices nay allow ohronio exposure to vapors which oust be avoided. In the history of the use of these fluids, there have been Instances when the fluid hss been sprayed Into open flames or - In the case where the fluids are used as hydraulio fluids - line ruptures have aaused 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 clouda of smoke and vapora 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, pleas* do not healtat* to let me know. Very truly yours. JTS+sf Enclosures Jack T. (Jarrett Industrial Hygienist Medical Department MOMS Q9QiSb