Document k63V1vkXOp9EpoV42wdk2rMjb

PUBLC HEALTH SLRVICE POOD AND DRUG ADMINi.STRATON : Robert K BcV.i finer, Phhft., ]>:lrecf.or O ffic e oi. Product cehrol.ogy (jj`F 400| DATE: J u l y 20, 137 2 from : R e tin s d ire c to r Bivi cion of Colorp A Cosmetics Technology (BF"430) SUBJECT: C acher ound Memo: r nelun on / `.l-e sto s in T a lc Asbestos is widely distributed in the environment, primarily as & component of man made artifacts, but also, in certain areas, as a component- of surface mineral deposits, especially talc. Because of its heat resistant properties asbestos finds wide application in construction as a component of floor tiler, shingles, wall and calling board, and paints. It is sprayed or painted on water lines end air conditioning duett to prevent beat loss or exchange. Around 600,000 tons per year are used In the building and allied trades in the United States, /'.bout 90% it bound so that it does not enter the environment readily ' } 200,000 tons a year are. used for miscellaneous purposes in fcexiles, brake linings, clutch facings, paper, insulating tape, plastics and other products where heat or friction resistance are important. The toxicity of asbestos was recognized as early as 1900 when r.sbestoro.s of the lungs was recognized both in miners and other workers exposed to dust. Later, asbestos was found to produce malignant tumors of the I pleura (membrane surrounding the lungs) or peritoneum (membrane surroundipig the Intestines), mesothelioma. This tumor occurs so rarely in persons not exposed to asbestos that its discovery in a patient is considered diagnostic of asbestos exposure. Recently, asbestos exposure has been correlated with an increased incidence of carcinoma of the lung, stomach, and, possibly, other sites. Asbestos exists in six major forms: chrysotile, anthophyllite, amosite, crocidolite, tremolite and actinolite. Evidences of differential toxicity among these various forms is difficult to evaluate because of differences in distribution in nature, differences in levels of use and the very long latent period before evidence of toxicity can be detected after exposure. Crocidolite was formerly thought to be the sole cause of mesothelioma and thus the most toxic form of asbestos. However, evidence gathered Page 2 * Robert M. S ch a f frier, Fh.B. by Selikoff Indicate:, that zmorl te end chtyauti. fa ere equally toxic with crooidolite. Chrysotxle is the for/:', co.manly used in industrial applications . Anthophy1111o has caused troubles in }intend Actiiiolite and fcreiaolite have not been as widely used for a long a period aa the others and their lack of reported toxicity can not be taken as proof of their safety at present, although, some experts feel that they are not as bad as the other forma. Everyone agrees that m o m study is needed. / Particle site is of feme concern. In theory part i d e a above 50 p are trapped in the upper sir passage:? Particles sisallor than this may enter trachea, bronchi or bronchioles and particles smalle r than 5 \x can pene~ fcrate the alvealo.e and be. retained in the lung. However, particles smaller than 0.5 p are generally expelled from the elvealoe end not retained. Several factors modify or eliminate the behavior of particles in the lung. Small particles may coalesce or adhere due to surface charge or moisture sbsorbtion. In the case of asbestos, fibers readily breakdown into fibrils. Even large particles va-ty be swallowed and pent rate the intestinal wall. It has not been determined if peritoneal mesothelioma is due to ingestion or inhalation of asbestos fibers. It is readily demonstrable that asbestos fibers penetrate the tissue of the lung forming a characteristic scar like lesion, the ferruginous body. These ferruginous bodies are found in 50% of the adult male population regardless of whether or not they have a history of asbestos exposure. Ferruginous bodies are so named because they attract and concentrate tissue iron. Animals working in (mules, donkeys) or riving near (dogs, monkeys) asbestos mines also show ferruginous bodies and changes in the lungs characteristic. of asbestosis. Because of differences in pulmonary dynamics arid species susceptabi.lity, no suitable laboratory model for ashes tor,is or carcinogenesis by asbestos has been developed. However, by various methods of administra~ tion, pulmonary fibrosis, mesothelioma and carcinogenesis have been demonstrated. The carcinogenic effect of asbestos has been attributed to trace amounts of metals such as nickel, iron or chromium or to absorbtion of hydrocarbons such as benzpyrene. It has been shown that cigarette smoking greatly accelerates the appearance of carcinoma of the lung in asbestos workers. Whether or not asbestos can eventually be rehabilitated by the removal of impurities is of little importance in solving the present problems. Methods and practices are currently available for limiting human exposure to these fibers. * There is a long latent period between asbestos exposure and the appearance of the various adverse effects. This has created great difficulties in Page 3 RobGirl: 1L S ch af in e r , Ph !; , defining done response relationships in both.tho level and duration of exposure. Rascth^liorna appears r ftor 20 to 30 yarn;.;, *Abet tor is usually requires 10 to 20 years to develop, while creinogenesir is rare before 20 years but approaches 100 per cent afte; dO or JO year.a* Asbestosis is said to have appeared afta : a single dry5a exposure. Mesothelioma has resulted from so little as six months exposure. The Iowe limit, of exposure time required for carcingenasis has not been, defined. Current opinion is that a dose of less than 100 fiber years will not produce ashestosis in more than 1% of the exposed population. The fiber year is exposure to 1 fiber/ral during a 40 hour; week for a period of one year. This level is not adequate to prevent malignancy. Tolerances for industrial workers are being revised downward and arc now 2 fibers/ml average for an eight hour day with peak levels not: tc exceed 10 fibers/ rn.1>5 u . A number of sources have reported the presence of asbestos fibers in talc. This asbestos is generally present as a natural contaminant in talc deposits. The amount varies within deposits and among different geographical areas. There are talc deposits which are essentially free of asbestos fibers. Tremolite is the form of asbestos associated with talc and, since it has no commercial applications, its toxic properties have not been well defined. The chemical characteristics of talc and asbestos are,`tidentical so that special techniques are required to determine the amount of asbestos present in talc. Two methods are generally use, optical microscopy and i x-ray diffraction. X-ray diffraction determines the percentage, but does not give any idea of the number of size of fibers present. This informa tion is readily obtained by light microscopy, but positive identification of the fibers can not be made. Amounts varying from less than 1% to 30% asbestos have been detected in commercial talcs. Preliminary studies for FDA by a contractor show that 27 out of 36 brands of commercial talc contain asbestos fibers. Experiments conducted for FDA at the NI05II laboratories in Cincinnati indicate that dispersal of 100 mg of asbestos (10% in talc) results in a peak level of 45 fibers per ml in the air. If this level can be extrapolated downward, dispersal of talc containing 2% asbestos should be within the allowable peak level of 10 fibers per ml. On a fiber year basis it would require 200 years of exposure at. this level to produce asbestosis in 1% of the population. However, if this level i>a3e 4 R obert H. S c h a f f n e t , i s high m u m to produco m alig n s,,ey in 50 to 70 y e a r s m ost o f th t f c . l c . v w a e I . . 50 y o n o f l i f e n n c y , n,i th e b a b ie s wo'uU have a l i f e ex p ect nncy o no re tli;m 70 years; r i s k i t should be elirnina-fced, f n x t th x s i s art u n n e c e ssa ry Asbestos has alto been detected in foods and drugs cither due to the Vi r o V f j T H :CS in che processing system or by contamination fr0Rl int'ula?XIf or <U>er ?.teriHr. in the environment;. ju certain ThttniH !' Ct,Simfry 1:0 COat U c e vith t;,lc ry inprovc its flavor. . , practicu of t.he rice way lead to asbei-tos contamination if the :C.used hc' a* spp^cidble txbeotos content. While ingestion has aot rteen stuped to the extent that inhalation has, available evidence indicates that introduction of asbestos fibers into the body by any route is or may be detrimental. uj > I- t S l o c V S TM 11 " * * ! * * " .*"* <* P o l l u t e by the EPA ih r ' 1-imtto fOi industrial exposure have been proposed by ' the Department of Ixbor (29CFR Part 1910; Fil lac 72-402) and' the m l 4 other th- f~ TM In summary, inhalation of asbestos fibers has been shown to be associated Tf V o T o Z ` ?T m X y diSCaSe and c-- of the lung and other organs of the body, lue amounts of asbestos fibers dispersed by the use of talc containing iso.e than trace amounts of this contaminant exceed the standards S v mbe8^ n l l ffr.ccupatlonal ^Posure. Although the total daily exposure h `L ThlV'f 1S f posurt- beius infancy and may continue throughout , , Theiefo!.c talc containing more than 1% asbestos by weight should be declared a hazardous cosmetic and banned from interstate commerce. The presence of asbestos fibers in foods and drugs is equally obAction able on the foregoing grounds and should be limited correspondingly.' rhquatt2* an economic fraud. At worst daily exposure *""h i g h ' l ' e v a l ^ f ^ m c o n ^ ^ dioxide Could contribute to the development of silicosis. Therefore Ifultl f , 1"! !rc **" fr" siUcTM -=1* .bould b. cmulirni adulterated and paragraph to that effect should be inserted in the statement on ashastos, . A lfr e d Weiss le r , Ph.D. (b)(5)