Document rxKz0jr6Gd9q9MmDVa5ag3rRq

' -1 a . (19799) Cta(Hrllt1 *r9*r ml llmlir tn 4l**rrl4tM. Ib*r. tet*r*l. it, *97-100. . Ml (lW> IHcmtmtvm ml fwetlM hmIim In !tncnl, *5 JW-tH. Mn. m*M, f. W, 9. (WM) TM mWHm f ftfrtet. Ttmi, frw. C*et. Sot. Iv(l Africa 55, 1*9-229. .4*l#y, A* ft. (1955) TW trrMal (Nalnrf \t aw tfteM*--trie CMmnli, Km, fw* Aypl. CM. 5. tiMO. * (M^ K< K. ml till*, V. R (19*5) Vm ft* MtMtM of AtKtt gr*vtft. Tram, KM* Soc. AIK, li)i Im-I0*4. jttar, J. 9. (1991) AaKtataa oni tKa aaWattfan Mtt of otnoroto* It. f. tliooto, Valrmltr of _ _ . _ , *l"C 9. M tottot, T. (19M) KrtHttfm vatMlM of m^TKmKU 4 ealrlUa. Selma* la arm. , mJ fallal, T. 09)9) A eoaporttow of oOWotoo Mbart rfth apUirtle eryaltla Mom * " Vet*Amm1 9.T. Aca. S<1. 5)0, 497-704. >, V. V., ftr.r4off, 0. D., oof ftort***, 9< 0. (195K) Maletallma of aMaKara. ftiyo. Rm. 109. 4*ft-4*4. "a'l, V. (19)0) A ototfotlcol iWy of |Ka ottomtA of awtor'offi. Trot. |)t, t*ftrn. ?ct*aal. Mai. SiaaVlota. % . mV*, 9, J, V* (1949) ttia atraetara of tollotoo croelfollt-, Acts fryotoilor* 2, 512- il. . (19#9) Kfaaralvtf, (Mtitrf oof ctyotallofropfcy of aapbtbela ooWotoo- fftn*ral.A*oe, CMula Shari Caaroa RoaaAoot 4, l*N. . Crooory, 9. A., oof KoCeHlooia, J. 1, (1991) Torotnotlotto of Mlrlpla*ahla lonolloo In Rraarflta aabaalaa. Minerot. Mof. M, IMS, * iff. r. r... M Corltvon, T. ft. (1994) CrovOt oaf awrybwloff of onaaitaw avlla rAtoleaa, J. Mar, Corn", foe, 49, 279*295. * *fo, A. C. (1929) Optic*! propertleo of (l)taaa oopMfoloo. HMD. Anmlo 9. 9. Mai. Sel, 5)9, . **d Wirjlwa, C. V. (1990) Cftoeoetortotle* of o potoooto* wfneMt* ooteotoo froo tie nlnwwor* tele flotrlet, Tonoo. Caaaflao Hlamt. 19, 101*10). ai4l, f. (19)9) Motor? of ootootoo-eelofrd otnerolofcfcol tatlaecf. MM 9or. Stanfarlt fra. fjfaf 504. 1*1*. . (19)9) Antoni!for* on! atltalar ofnetol ftagataia. Amtolo 9. 9. teal, Sal. 5)0. 497- :o4. . (1991) larfaca otroetoro on* otrooctli of ftWro oof otvonc polycryotelllno ootortolo. "* VapAHatel awoaoctlpt. * oaalt, t. anf Coco, 9. (1959) Tonotlo otrenytt of ootooto*. tetara 19), 95-57* . f- Chapter 6 The GEOLOGIC OCCURRENCES and HEALTH HAZARDS ol AMPHIBOLE and SERPENTINE ASBESTOS Malfolm Rost I : mirooucTiott The problem The widespread me of empblbola end serpentine asbestos* bp Indus trial society has contributed greatly to human safety end convenience by service In brake end cloteh facings, electrical end heat Insulation, fire-proofing nsterlsls, cement water pipe, tiles, filters, packings, construction nsterlsls, and many other producte. Tet, while these very tangible benefits were accruing to our society, sosie asbestos workers were dying of esbestosls, lung cancer, end mesothelioma. The hazards of certain fores of asbestos under certain conditions have been so great that several countries have taken extraordinary ac tion* to greatly reduce or even ben their use. Recent experiments with animals demonstrate that the commercial asbestos minerals as well as other fibrous materials can cause tumors to form when the fibrous parti- 2 cles are Implanted within the pleura. These experiments have convinced some health specialists that asbestos-related diseases can he caused by many types of elongate particles; the mineral type, eeeordlng to these health specialists. Is not the Important factor In the etiology of PRODUCED BY FORD 09 O o D! o o VI o 09 At present, the most widely used definition of asbestos by vari ous groups concerned with environmental health problems Is from the no tice of proposed rule-mnklng for "Occupational Exposure to Asbestos" published In the Federal Register (Oet. 9, 1975, p. 47652, 67660) by the B.S. Occupational Safety and Health Administration (0SHA). In this no tice, the naturally occurring nmphlbole minerals omosltc, crocldollte, onthophylllte, trcmollte, and actlnollte and '.the serpentine mineral chrysotlle are classified as asbestos If the Individual crystallites or erystol fragments have the following dimensions: length greater than 5 mlcroneters, maximum diameter less thtm 5 micrometers, and a length to dlometcr ratio of 3 or greater. Any product containing any of these minerals In this size range is also defined as asbestos. *The lungs are Invested by a double membrane, the two layer* of which form the closed pleural soe. For discussion of these animal experi ments see Stanton and Layard (1978) and Pott (1978). i 279