Document BRDReXvrgoezxqzQZmz5OD6X

FILE NAME: Talc (TALC) DATE: 1971 DOC#: TALC123 DOCUMENT DESCRIPTION: Excerpt from Barry Castleman1 Master's Thesis - Asbestos-Effects on Health ASBESTOS-- EFFECTS ON HEALTH by Barry Cast lemn An e s say submitted to the Johns Hopkins University In conformity with the requirements for the degree of M a s t e r of science in Engineering. Baltimore, Maryland October, 1971 42 "Por the past 10 years, during which spray fire proofing came to he extensively used, it was not uncommon to see extensive snowfalls of asbestoscontaining material over widespread areas of New York and other metropolitan cities. In some cases the fireproofing was even done with no attempt to enclose the spray area by tarpaulins or other means." (1 3 6 ) Sampling around construction sites where extensive spraying of asbestos fireproofing was in progress demonstrated a significant contribution to asbestos air pollution. In some Instances chrysotlle asbestos levels approximately 10 times background" were observed. A few months after this report was made, the use of sprayed asbestos insu lation was totally banned in Boston and Chicago and severely restricted in New York, Los Angeles, Detroit and Philadelphia (138). Another suspected significant source of asbestos fiber was abrasion of brake linings. Lynch examined the emissions from automobile brake wear and found that practically all of the fiber was destroyed by the heat of friction (139). schulg and Williams (115) analyzed 51 different samples of commercial talc and found tremolite as bestos present in greater than trace amounts in 17. In fact, three of the talcs were composed 80% of tremolite. Wright stated that (xHo) "talc provides a potent source at least equivalent to that of asbestos for supplying respirable sired fibers that could produce ferruginous bodies. It is difficult to conceive of a better way of having fibers Inhale than the use of c o s m i c t a l c powders..' This 1 1 of thought is contradicted by results of the any studies of asbestos body prevalence in populations. Th,s. have established that asbestos bodies are ore prevalent in ales, and in individuals with nunerous asbestos bodies it was usually in men with assumed occupational exposure to asbestos. Talc, with or 1 Aov, nf tremolite asbestos, ay be harmwithout inclusion of tremoiiv ful but there is no evidence to show that it is a cause of disease to the extent that the major forms of asbestos are. Hnnoluslon sellhoff and coworkers (1*1) estimated that there are fewer than 100.000 workers regularly using asbestos in the construction trades in the United States. let more than 3.000.000 other bull m g trade employees work in the same structures. A large number of workmen have similar indirect occu pational exposure in shipyards (1**). In addition, there are people with family and neighborhood exposure 134. Meurraan, L. Environ. Has. 2, 30 (1969). 135. Lynch, J.R. and H. E. Ayer. J. Oooup. Med. 1 0 , 21 (1968) . 136. Nicholson, W.J., A.N. Rohl, and E.P. Perrand, Paper presented at Second International Air Pollution Conference, Washington, D.C. (1970). * 137. U.S, Department of Health, Education and Welfare. Air Quality Criteria for Particulate Matter. NAPCA Publication AP-49, Washington, D.C. (1969), pp. 13-14. 138. 139. New York Times News Service (July 14, 1971). lynch, J.R. A.P.C.A. Journal 18, 824 (1968). 140. Wright, G.W. Amer, Rev. Resplr. Dis. 100, 467 (1969). --- 141. 142. 143. 144. Sellkoff, I.J., E.C, Hammond, N. Helmann. Paper presented at second International Air Pollu tion Conference, Washington, D.C. (1970). Harries, P.G. Ann. Occup. Hyg. 11, 13 5 (1968). Hourihane, D.O'B., L . Lessof, and p .c . Richardson. Brit. Med. J. 1, 1069 (1966). schepers, G.W.H. Ann. N.Y. Acad. Sci. 1 3 2 . 246 (1965). -*1-- 145. Kuyper, L.N. Pneumoconiosis. Proceedings of the International Conference. Johannesburg 1969. London, Capetown Oxford Univ. Press (1970). P. 42. ' 146. Sluis-Cremer, G.K. Environ. Res. 2, 310 (1970).