Document pzwx2v1VEonm7XgE52va1x6E

FILE NAME: Z//E DATE: DOC#: /E DOCUMENT DESCRIPTION:ZZZZ 1V 1 'I j,i: rt'l'7 t\ /-tc/f <. n-r A 1..1 L L r: r, ,,../ ('vv'1)1 -t ~ 11/ IIr( I ~1 t "I --,, '--' '- ( ~fvt2 ( L~-<-<- 1 1) T S-) ./I J r -.:(/ Vl Health ASBESTOS AND ASBESTOSIS W. J. Smither The Forms and uses of asbestos Commercially important asbestos .fibres fall into two main groups. The first of these is chrysotile, and the 5econd comprises the arnphiboles. Bnth groups are fibrous silicate~. but they differ in geological origin. in chemical composition. in molecular structure, in fibre size and strength, and in other characteristics. Chrysotile. white asbestos. comes from many diiferent places. There are slight chemical and physical variations in the fibres from different sources. but b:i;;j. cail: all have the same molecular strncture. On the other h:inJ. the amphiboles comprise at least three separate type". whose molecular structure is very similar. but whose clicmical ~nd physical properties differ more widely. Amositc (amber) and c1ocidolite (blue) arc of commercial importanc,_' in this count;:. whereas anthophyllite is a Finnisl~. fibre not u.~cd here. The relati\c :lmnunts of each fibre in wcrld production i-; shown in the figure. Asbestos Annual world output-3.000.000 I Chrv~0 tile (,~l,JTC) 2 '")0 :~)f\ ton'> <)3 ~~ C..tnaJa I.250.000 USSR 750.000 S. :\frica 250,000 USA 100,000 Europe 100,000 Others 35U,000 ' Crocidotitc (bl U~) (South 1\fric:1) 110,000 tons 31% I I Amositc (Soutli Africn) 10.000 tons 10' N World production of nsbcsto~ tnn<> - (-- -- ----- h0b /\n t :1yII ite IF1nl.:ml 1 in fl(lJ0o,,""" 62 63 The different characteristics of asbestos fibres dictate their uses, applications and their mode of packing and handling. For example, amosite can be pressure packed and palletized, whereas chrysotile lends itself more readily to containerization. By far the greatest use of ch.rysotile is in the asb.::sto:-. cement industry. Amo-;itc i<> used mainly in in:-,ul 1tion and building nrodacts. Crocidolite, due to its excclk;1t acid resista!1'::e. finds it" major ap;-,lication in the manui.1c turc of h:11t::y bo::c<; in this C'.'lUntry. It is ;icLkJ to tl-ie pit..:~' mi~turc in unopened dissoluble bags. Very broadly it can be said that current friction mat~ rials. whclh.:r they be disc brake pads, passenger car .rnd commcr.:ial vchidc brake linings or clutch facings, contain 50 per cent chr:;cotile :1,~csl'1S. The new trends of dcvd1'p mcnt. rr~rti,t!l,:r':: in <he licllh nf disc brake pad,; and :.: _1mmcrcial vehicle brake linings. indicate that the percenta~c of a<>hcslos included in the mix is likely to decline. Some 1':.v materi:tls now contain approximately 40 per cent ash.~'t'1'" and newer mi"'(CS can be foreseen \Vith an even lower pcrccnta~;o:. pro!"':!'.-:-ly down to a minimum of 30 rer cent. The pads for di:;c hr:.!b~<; require less asbestos fibre tb.n conv..:nfr"'nal dr':'.n br:1i.::c linin:;<;. It is estimated that more and more -~T;:;c1gcr cars produced in the U.K. will in future he cquipr::d with disc. brakes. particularly on the front w:1~els The bioin;;c:il errec~> of asbestos The vari:ltions C'(i1ting in th~ biologicat -.:ffect<> f1f 1hc <lrfferent type;; cf asbc:,tos is the subject of considerable i:;tc:-~,-t :1r.~l rcs;::3rr:h. "Tld the extent tn which th! nh)c;i-::1l and clr_'mi:al cha:-actcri-,tics of the :!sb.:-.:tos it".:lf irifl:::qc:: hiolo~~;c1l c!Tcct<> is beinq; invcsti!Iated. The role of tnce clement:> and coritaminant-; ass<Y:iated with t!1e !lbres h3s al~c) to be considered. Ti1c chief bio!cgi:::tl effects of asbcsto<> arc confin~d t.:,, the lui1g and pleura. or lining of the lung and chest cavity. , . ?- ,;~(i 64 and to the peritoneum, or lining of the abdominal cavity. A few cases the~e arc of skin corns have occured in asbestos becoming much less common. workers, but All types of asbestos, if inhaled in failly high concentrations over a considerable period of time. may cause fibrosis of the lungs. Thi'> disease. called asbestosis. co,1sb,ts of thickcn!1g of !he !u11g membranes with result.int <>tiffening of the ti~'>ue~ :?11d interfer~nce with tnygcn uptake. The interference with ;as tr:rn~;fc:- is the reason for the shortn~~s nf breath which cau'ies the disability associated with asbestosis. The a mount 0f expc,~ure required to pr0duce fibrosis of !he p!cura. with or i~ m.1re dcb:1tabk. without calci:1m dcpo'>itian It may he that :,1;:1:-tcr. kss in the scars. concenlr<.1tcJ c~posurcs. riarticularly in ynuth. leave this mark uron the nlcm;;_ fn <.\;1:; cv.!:it this oani::u!ar cffc1:t of a-,bc'itn-.; inh:il.1- fion caw,1:-; little or no lfr-ahility in i:;c!f. f=-:ry,q1r,~ !D a-.,h>~0; may k:td tn furth.._,'.. l,;:iwlic:,,ti0n. r '=' :~c:r~ f:ii!i'.:2. cancer ;)ft!..:: JL;ng. lr. ;:.i:~I:.. ! '::'.'.1ii;;1:int ch1 ;: .1 ~.; in C;'.:"c.:.::r ci" th: ti!: niLk.:1~:1! nh<('.'Sr b1cccrnito~nhcu~-1.mv.n k:iPw:1 a~ m.:: ,othdi,ima. w fx mJrc cc:11rn~)1J in ;:-bc::,tos w0<c::> ~vl1n <moL:c, jw;t 1<; it is in the ,'.!t:ncral ropubtion. ~-!c~ollic!i._,rn;!~ :'.r.: .er_. :;n:on;;1w.1 ::-xi~houl the 1vcrld. hut in -.;0mc ~: !T:is d1~v f~n .:: be::n a -;soci'.1 tcd :norc f;r1.:m:_;1.~1i~lrienv~r waint Itihocpxhpyol.l;iutrec. toThcehroreca<i;J-o':l1i~tc ~th5 atn:1:slo:!crehry,1st optirlce-. 'C: : ;1h, :ure. but are bcin;:; soughL int~nsivci) by investig:11.. ~, 111 many different countrie~. "THE A~X\LS. OF 0CClJP.\TION-\L HYG!l::-1[VoL 13, No. 1 fanu~:ry !970" " ~',, ~,, ', PHENOL <CH-.OH> AND ITS CARE Although, to-day. Phennl is a basic raw material, used in large quantities by many industries. it was ori2inally used as an antis~ptic. Ln.ter ph~r:c1 found u~e 1n the ..:yothc~is '-;.. . ' ' , ,'~_:i ~~~ ~~ -~ ":~ <': ,:..~' -::~ <::.._~ ~- :-~~- ~.:~~ ,::,~~~~. /~-: ~~ ,(~ ;: '-, :~;..-:. ~ - ii ._' f; it 'i -#' 65 ... ~. ~" or dye". the newly discovered aspirin, and one of the first l:''i high explo5ives, picric acid. Phenolic resins are now one of the most important ap pli ...ation-.. of phenol. Their uses are wide and growing. They arc used a<; moulding materials, laminates and adhesives ; other derivative:'> of phenol go into the manufacture of plasticizer-.;. ph:trmaceuticals. photographic chemical<;. so1ps. dye..:tc1ff..;. germicides. preservatives, inb. paints, glues. textile.. e'<ph1sivcs and weed killers. Phenol itself i.,; widely U"l)'J a..; a selective solvent in p.::rtoleum refining. ~md Phenol having a flash boih at aprroximately point of 80C, melts n "i0-41 C I80-182C al normal atmospheric prc"surc. Phenol i.;; flammable aml its vapours mixed \'- ith air can be e\.ph)sivc. Phern1l j, highly toxic and i.~ readily absorh..:-1 e\'..:::1 thr\t~!' :.-.:t:t lunbro\cn) skin Th(: ~rc~tler th.: ..-c:'. 'f <,i: ......1tami;1at~d. lhl! grca~er .he Jan~.!!. In coi1\;t:t '" ;_:1 ~k "i. n!'.::10! ";ill ca use p.1inful or J::n:.;crou~ burns: <'.i~d if L~L i: will le ,!\l'nl~')cd i:1to bl ,.,)c{ :o.tri::.im. ll i-; ::ho t0<ic \\hen . :.:allo\\d tH. when its vnpour ~s inl1~tkd A fe\1' -,cr:uu... and f'Jl:1I a-:r:id~nh w.:re caused d~;.:: to !(11~;t, \''~rkr i\, i.l1!1r,1:i1.T handii;ig and lack \)r \.:.nowld_sc rcprJing ih .._ .~ " " ' l ' '- tl~\,,.1'1'.. 111111.,.. .. R'"'nd\ 4. .,_,.._...., - - ()'11.\..'..'- ' ' ' ~ 1i'd :,1 "~ 1 fI.~,~._ t<'ry while melting :-;olid j!henol c.111taincJ in a \d,.ro~.V1111 ~ iti1~rnl loo ...cning its bung. on a naked flame. Prccm1iions : 1. Corro~ivc toxic chemical..; s!1,mld ahvays be handled carefully teristics b of y op th~ erat ma ives teria w ls ho an a d r e tr fully ained i nforme in the d p on rop th er e h characandling: p:-ocedure. It 2. Workmen wh0 h ndlc .a k phenol should wear gas llg 1 bb crloves and rubber boots. safety goggles or face m,ts ru er ~ . p ~-====~--