Document JNXzOGKNBRQ7BaXJ6zpy1r3dr

MOUNT SINAI SCHOOL OF MEDICINE of The City University of New York FIFTH IV(NU( AND HATH STIfCT* HIT YOK, NT. I0M /^ % Drpartauat tf Ci"*"irf ZMrJicimt July 31, 1973 Mrs. Marie Ehrmann Li bran an-in-charge Research Center Library United States Gypsum Company 1000 East Northwest Highway Des Plaines, Illinois 60016 Dear Mrs. Qirmann: There is a vast literature reporting results of investigations into the comparative toxicity of chrysotlle asbestos, in relation to other fibers. In summary, no significant difference was found; allvarletles show Important flbrogenic and carcinogenic activity. At your request, we will provide some of the most pertinent references. Insofar as human effects are concerned, it is conceivable that the animal models do not reflect a difference which might exist among the fiber varieties; this possible difference is the subject of investiga tion in a number of ways. Dr. McDonald considers that his studies la the chrysotlle mines in Quebec have shown less lung cancer and mesothelioma than other asbestos-exposed groups. Very worrisome is his observation that more heavily exposed chrysotlle miners had five times as much lung cancer as those more lightly exposed(l). This would provide clear evidence of the carcinogenic effect of chrysotlle asbestos, slnee the individuals concerned had been exposed only to this fiber variety. Too, review of x-ruys among these men has shown numerous eases of asbestosis, demonstrating the flbrogenic effect. In addition to mine and mill employees, studies have also been under taken of factory populations thought to be exposed only to chrysotlle. This is more complicated, since it is difficult to be absolutely sure that the populations concerned never hnd any exposure, however small, to other fiber varieties. One such study was reported by Dr. Thomas Maneuso in 1963, and an important cancer risk of the population in vestigated was found(2). Another study has been reported at scientific meetings by Dr. Joseph X. Wagoner of the National Institute for Occupa tional Safety and Health. While this has not yet appeared In the scien tific press, I am sure that you will 'js able to obtain a copy of the manuscript from Dr. Wagoner. ILrs. Marl* 2im*rm -2- 7/31/73 Dr. Joseph Wagoner, Acting Director Division of field Studies b ClliUctl Investigation National Institute for Occupational Safety and Healt 250 Main Street federal Building, Room 7C53 Cincinnati, Ohio 43202 In obtaining information on the question, advantage may be taken of another set of clreuastanees. Aaoslte and eroeldollte, the other two major fibers used In cotmaerce, are not rained In North America, and aust be Imported. Records of these imports have been kept by the Departaent of Coaneree. We find that only trivial quantities of these fibers *era Imported until the 1940's and of these saall amounts, eroeldollte was not used in any insulation raaterials, although aaoslte was. Therefore, experience of asbestos insulation workers during the 1940's and 1930's (especially, the fomer) cannot be ascribed to other than the one asbestos fiber that was in regular use In insulation aaterlals during the 1930's - chrysotlle. Since lung cancer rates, as well as the occurrence of aesothelioaa and deaths of asbestosis, were deaonstrably Increased among these aen during the 1940's and 19S0's, we aay Infer the chrysotlle-assoclated risk aaong thea(3-S). Since the problea Is an Important one, X expect that more Information will becoae available within the next several years. Sincerely yours, IJS:jlr 1. McDonald, J.C. , McDoni.ld, A. D., Gibbsv G.W. , Slemiatyekl, J. and Rossiter, C.E. Mortality in the chrysotlle asbestos nines and mills of Quebec. Arch. Baviron. Health. 22(6);6T7-686, June 1971. 2. Mancuso, T.f. and Coulter, E.J. Methodology in Industrial health studies. The cohort approach, w*;th special reference to an asbestos coapany. Arch. Environ. Health 5(2):210-226 (Feb.) 1963. 3. Sellkoff, Z.J., Churg, J. and Hnanond, E.C. Asbestos Exposure and Neoplasia. J.A.M.A. 188:22-26, 1964. 4. Sellkoff, I.J., Churg, J. and Kammond, E.C. The occurrence of . . asbestosis oaong iruulation workers in the United States. Anns. N.Y. Acad. Ses. 131.(1): 139-133, Dee. 31, 1963. 3. Sellkoff,' I.J., Hrnmond, E.C. and Churg, J. Asbestos exposure, smoking and neoplusia. J.A.M.A 204(2):106-112, April 1968