Document mvOyR55jgGr5jYRq6DQd1Em0

FILE NAME: Z//E DATE: DOC#: /E DOCUMENT DESCRIPTION::ZdZZZ ,J.~ r: . (._ ,?-THE DnESTO . . .Jti1~,s~ .- , . . Ni~ J:l*an~ues----:- the.soft and coiled"~ pcnunc vancty 9CCurnnf! a<; chrysot1 .,.,. '- fibres. and th~{ straight arnphiholc CONNECTION "o. ~6J~~~r~:l~Cnug~~t.yt~it~~(;;~t~~}1i~~: Q r ' ,n_{ f', .,__)"'-. ~ . 'L>- (_>:~)-' As:-:: ::o:::s 1s being increasingly linked with a number of ser'ous diseases. Studies show some workers in the 3.Stestos 1ridLstry in India are suffering from asbestosis ' actrnohte. etc. Ninety ncr cent ot the 6 million tonne~ of asbesto~ mined in the world i.., chr\ ..,,>tile and about 7 per cent crocidolite. The phy-;ical properties ('f the f brc\ pla~ a rok in cau-,1ng disea<,c\. n' ,,c ..,hall ::'elater. For instance. tht: ~oft :niL' the 1.. 'Ilcd vanetv c:wsc~ a~hc\10-..1' wh:le the harsh ar1d the" ti ft va net :c' can penetrate the lungs and reach I l ~ c1n1q~c characteristic,, . t"L. ,\rength. wear-resistance ."h! tlex1b1l!tv have found . - . "l'~ u"cfuf in over three .- .--.: _,immercial and industrial _:-:- __ ~ -:-.. but 1t ha<i one serious - '-a~,:--:' can ':ause severe health :> ../ "rds. inhaiation of asbestos and its ..2:<'."',_:-s1on m the lungs can lead to _,,;--.._,rusi-; (a lung disease), lung can:er -'nd cancers of the membranes lin1n~ 1he hngs and the abdomen \ me-C'thelion1a of the pleura and the fldltoneum). The Factories Act, 1948, stipulates stnn1o1~nt preventive control measures agz. )a~bestos exposure, protective '"'qu,, ftient for workers and their periodical examination. Because of the ,,eriou~ nature of asbestosis, it has been made a notifiable disease under 5ection 89 ot the Factories Act, and dbo a compensable disease under the Workmen's Compensation Act. Though there are no Indian stanJ,1rJs~ international standards set limn~ tl> asbestos exposure to workt:r'. ranging from two fibres per cubic ~ent1metre (2 million fibres per cubic metre) to U.2 fibre per cc for different \ anetie~ of asbestos fibres. But the -\~he~to~ Wdrking Group in the US reported in 1980 that there is no safe expo!->ure limit for asbestos, that all ct)rnmercial and several non~,>rnrnercial forms of asbestos cause d1~ea...e and iecommended a new stan- lL1i J uf n l fibre per cc as a maximum \\ 01 ., t exposure limit. This is the -.,11L1 ' quantity that can be mea,u1 ed b1 tl'chniques currently avail- Jtik De~p1te this awareness and the ,r,1tut,lry prov1s1ons, workers in India tr1.. 'till expo'>ed to much higher levels '1! .1~bestos, and some suffer from c1-.,be~tosis a~ revealed by studies. car: >cd l>llt ,o lar. In a study done 1n .11' .i~bequ-; cement factory last year i" .111'. ;nu hor and Dr. V P. Gupta ot chl ( entr,il Labour Institute, Bom"1,1\. \\t: lound that 6.5 per cent ot the i2tl "")rker-, exarmned suffered from d'bc,lO'>lS, ,.:nvironmental measure menr~ 'bowed asbestos concentra: 11 in, :,t'>O\ c 1he threshold levels in two -.,c',:!"n' '.\Ithrn the tacton And in A.pril this year, Drs S P Shah and S R Kamat, of the Department ol Chest Med1c1ne, G. S. Medical College and K. E. M. Hospital, Bombav. reported 24 cases of asbestlhts at a conference on occupational health. No case of cancer due w c!sbestO'o has, however, been notified yet. This can be due to the fact that asbestos workers are not followed-up after they retire and occupational histories of cancer patients are not recorded. In cross-sectional studies of workers, it will be difficult to find a person who t'> still working while suffering from lung cancer or mesothelioma of pleura. The asbestos- industry in India employs about 7,000 workers in 19 units spread in Andhra Pradesh, Gujarat. Haryana, Maharashtra and Tamil Nadu. Much of the asbestos used here is imported, and Dnly a small quantity, about 20,000 tonnes, is mined in Andhra Pradesh, Bihar and Rajasthan. Various studies and reports in the press have recently highlighted asbestos health risks, and this has caused an increased awareness among the management and workers, re~ult ing in improved working conditions But only a continuous follow-up will indicate whether the hazards are sufficiently controlled or not. Unlike in most other ca~es of occupational diseases, a-;besto~is has no cure and continues even 1f the afflicted worker 1s removed from the source of exposure:. even 1f condition~ are better in a factory today. the his- tory of past exposure becomes a key factor, since asbestosis develops slowly and appears after l 'i to 35 year<; As for mesothelioma, even a short c:.;posure can cause it, and it is difficult to prevent. All this ha~ prompted a ban on the use of asbestos and a ~earch trn substitutes in some countne-. h is als(J statutory m wco,tern countrie~ to u-;e a warning la he I on a.,lie..;to<. pt (1ducl'> Asbestos and its uses A naturally m:currng mincial, consisting mainly of ... i1ic,1te'> in the fibrous form, a~bestos derive~ it' name from a Greek word meaning "unquenchable . it cnmc'> 111 tw(1 the pleura to cause mcsnthchoma tlf the pleura . The mineral fihre<. arc procc<;-,cd or mixed into various produch tioor tilings, gaskets and packing.., huildm materials dS asbe<.tos ce~~s she.et~. iri.c1ion products l;kt brake and dutch linings, paints. coating and sealants. asbestos reinforced~ plastics for electric motor components. asbestos cement pipes for chemical proces~ pipings, water suppiy pipes and electric wire conduits. asbestos textiles for heat and fire--protective clothing and draperies, asbestos paper for beverage filters, gas vapour ducts for corrosive compou;ids, electri~ wire insulation, etc. Nearly 80 per cent of the production in India goe~ to make asbestos cement. In several of these proce~~es, a~hes tos fibres and dust are released dlld inhaled by workers Particuiarly dusty arc mixing of fibres. disniantimg of old laggmg. '.'.praying :.isbtstos fibres on walb and ceilings. carding. weavmg :ind spinning of fibre~.. twistmg asbestos around welding rods, use of asbestos for rope. either dr\' qr wet. to grout expansion gaps bctv. \~en rcfrac tory bricks in furnace~ an J kilns and clearing and maintenance of .:xhaust ventilation ducts and disposal unib The risk of getting a~he.;,tosis i' the highest in the textile ma1rnfacturin!! an~d in~ulation processe~ where the tihn:-. are fmelv divrdcd ind '' the lea'>t m a"bestc)s m1111ng where d1r horne fibre-. are vcn fc\,~. it has been estimated that asbe~tus in<.ulat!on wqrker~ are eight time-. mure !tkl:ly to Jevelup lung cancer than the ,c!encral population; for ~moker<,_ the n"i... 1'- nmety -two times higher. The size and type of the tibre~ <1ml how they are di'>pcr~ed a1 c important rn causing the hanl!d~. Har-.h dnd 'itraight f1hre~. MC more likd\ to rc,ich the iKnpher\ nt the lu!!g~ <llW thL pleura; crocidohte. \\ t11ch 1-. a ..;n.nht fibre. 1s more likely to cat:<;e mc'>othc:Jioma than c)ther fibre, '"loft ind coiled fibrt~, like chi '~'itik rnll anthophyllite, arc proha 1!) mv<JtHJ 1nore in a~he'-;tcy.a\., Fihrc' longer thdll 200 1111crometre-., :ind w1de1' th<1n _-;  / _.,.._ micrJ:netres are intercepted in the nose and cleared by the cilia. The de- L re,1smg diameter of the pheripheral _imvays in the respiratory tract also help~ ~)!,Kk the larger fibres. Disper- , 1n is dnothcr important factor; wide i1~per~1on alluws dust particles to p,nctratc Jcepcr into the respiratory -,vskm :rnd m this wav the manufac- tt1 re of .1~lv:stos textiles, where fibre~ Jre Whklv dispersed, is mnre danger ,1us fb<1t a~be5tosis is a serious atflicr10n among asbestos textile workers \\a~ established beyond duubt by the JlJ30s (the first case was reported in the l:K m 1900). In asbestosis, the 1nh<1lcd fibres damage tlie airsacs in "10: !ur.gs. This impairs the proces;; of gas exchange between the oxygen m the inhaled air and the carbon dioxide in the blood, and turns the elastic tis- sue between the airsacs into rigid col- lagenous tissue which is termed pul- monary interstitial fibrosis (Fig. lL Consequently, the lung function is restricted; the person feels increasing- ly breathless on exertion and finally disabled to varying degrees. Andonce the disease sets in, it progresses even after the worker is prevented from further exposure to asbestos, and Fig. 2. Asbestos bodies appear as elongated, golden brown structures, 20 1' ~po rn1crometres long and 310 5 micrometres wide, with dumb-bell-shaped end~ _} there is no specific treatment. Asbestosis, however, occurs only in occupational asbestos workers, and depends mainly on cumulative exposure to asbestos dusi. Smoking increases the nsk. Ho~ is asbestosis diagnosed? This is based on the history of exposure to asbestos and symptoms of breathlessness on exertion, end inspiratory crackles (crackling sound heard at the end of the inspiratory phase of the breath ~ound because of the forced opening of the smaller airways which are closed during inspiration due to mterst1t1al fibrosis), reduction of lung function 5uch as transfer factor and 'ital capacity, finger-clubbing or the Area of lymphatic vessels --------- f-T~zJolJm-J--- ~ H1lu~----1 thickening of the nail beds (which can occur in a variety of respiratory, cardiovascular and other diseases. or may even be hereditary and not specific to asbestosis) and radiological findings of parenchymal fibrosis. According to the Pneumoconioses Medical Board. UK. a worker who ha<> been exJX)~d to aslJCstos and shows any two of the above symptoms and disability is certified to suffer froJ11 asbestm,i\ and one with the ~ymptoms but without disahility as "possible ashesto'>is" Using this criteria. we conducted a study, selecting 120 worker~ at random out of the 960 employee-; in an asbestos factory 111 the middle of 1981 "''1J 0 E (.) c e.0 (The workers were ~ubjected to thorough medical examination. includ- ing lung function tests and cl)est X-ra) full size~ The results revealed that 20 worker/suffered from .1sbestosis, and o.howed 'restrictive-type reduced lung function. The worker~ were ex- posed to both crocidol!te (blue fibre) and .chrvsotile fibres, and fibre con- -:entraticm" were highcl than the per- missible levels in the fib, e grinding <1nd loading, and p1p"'-fl!mhing de- partmenh But the 20 Ml! f..c1 s suffer- ing from asbestosi~ we re <,cartert'd in all Jepartments. This ,\a'. prob1bly due to high exposure 111 the past (for 1~hic:h there wa<. no 1c-ord) rn all de- partment<. and rn;e t de part mental mi 'u xin res g - o in f t hweorfkoe~c,toD~uastd c ontro been l me ritr a- o- duced onlv t\\O ve~ bdor<: tl udv whik the afflicted worker, hau 6cen el\pthcd for an avcr.t.!<' .11 12 yeMS. And frn the ,,ame leneth ;ii c\OOsurc. ashc~tos1~ inc1denc.cL >\'il' highei 1!1 ~mukcVi than in nun-,mtikcr~ rvje.i- -.urc~ to contrPI expo :urc rn )he t\\ c dcpa1 tment'> and cfftct1\eL!2.:_eJ1cc1l !ft) momtoring of all cmpl11vc;.'\ were ~ug 1!<-''-!C'.i to the manage 111. !'here 1~ a pomt to rL'll11.:mhc1 i:-:r~ __ j__ _ \ Main Respiratory Tracheal bronchi Bronchi Bronchioles bronchioles ...___~-~~~~~ Conducting airways Respiratory unit Alveolt A pcr~on who inhale a-:he,10~ II '>r ,-:, mc1y show asbestos b11d1c' rn lhc ,putum, ind the pre~l'flCt uf 'he-,': f11d!e\ in the sputum i~ g.c111:1ctll:. 'ilJ',takc"'1 :~ Illdtcatc JShC;.lU'I' ;hl, '' 'l<,: 'll '1g 1 Conducting airways and the respiratory unit Sizes of the bronchi and bronchi0tes have tJern shown shorter and the respiratory unit much larger A~bc-;tos fibre~. ,m rc'<1chtnl! th._~ -~ir 'ac. cau~es hlmni\_,,J, ;-,.:-~',lli'~ Jt /(i/~toant-wconr hemoglol aheolar asbest0~ tkn,e~ "r coatm!-. 11 HS. L'\t<JP cell ~alt'1 tm hodie mechani5 m.rng a- sputum appear g1 dumb-be Jn l!Cnl =-~;;-::::.J ;:_~ ::Th.i'Oi nx :hr> resuh :irru. l~ rr:1nur su:e, anc tr:an non are at n1 tubercuk are at hi cancer. C" "\er-c ,.i-6ch ' by the c asbesto~. health h< Merewet on a stu1 recordin~ dies ~on Cdl1Cer de cancers_ mon in tl unlike :i related. , heen (1bsl group A r~k. Me~otl peritoneu ocGuring and is sol, po~urc. E n1< \.'La 40 _,_/,re. smokinp cancer ha t1ves of , been exp clothes Cc tion' ne mine> ar non-occt: 1'h1s part1 h;gulatln 'narntenu product duthes d that the \~i)rk Ck)I (fh1\Ug.I nom .sh )r 100 cted to , includ:st X-ray I that 20 Jsis, and reduced ~ere ex1e fibre) Jre conthe pergrinding 1ing des suffertered in >robably )ast (for n all detmental rol~ n ritro- !\ .idy ao oeen 2 years. (po<>ure. ighcr in s. Meaihe two niedical iCTc sug- ier here. os fibres the spu.e bodies :taken to not .;o ~tation. This liberates hemosiderin /(fr1on-containing component in the hemoglobin) which is taken up by the alveolar macrophage along with the asbestos fibre. The macrophage con- denses on the asbestos fibre to give it a coating of hemo:,1derin and protein of its cytoplasm. aml the macrophage cell wall rupturt.'~. giving rise to asbes- tos bodies This 1s hasically a defence mechanism. Under light microscopy, using a wet smear from a centrifuged sputum specimen, asbestos bodies appear golden yellow, rectilinear and dumb-bell shaped at the ends (Fig. 2). In general, asbestosis, appears 15 to 35 years after first exposure to as bes. tos, and the uccurrence i~ time-and dose-related: this means that the disease showing up today is not necessarily the result of present-day work contit ti.ans. The risk of contracting asbestosis is minimal below a certain expo- sure, and smoker~ carry a higher nsk than non-smokers. Asbestos workers are at no excess risk of contracting tuberculosis, but asbestosis patients are at high risk of developing lung ercancer. ~r-causing capacity r-.~uch concern 1:,, now berng caused by the cancer-inducing capacity of asbestos. Lung cancer as an asbestos health hazard was first reported by Merewether in the UK in 1947 based on a study of 235 death certificates recording asbestosis. Later, other stu- dies confirmed this. Asbestos lung cancer does not differ from other lung cancers. except that it is more com- mon in the lower Jobes. And though, unlike asbestosis. it is not dose- related, significantly greater risk has been observed in the highest exposure group. Again. smokers run a higher risk. Mesorhetiom& vf pleura and the peritoneum is a r.are: form of cancer soiew oquring in me generni population. and is attributed m asbeS{os ex- pe---su.re '!;ca an e-~~urc ~ shn:t ~a ~\. -<i~fil:~~;~s.::_~~~k~a~~L~~,~~; ~-~~~l~l s::::.-Jk:r:g ;::::..:- --~;:: T:-::,: :ype . : cancer has been rq1orted among relatives of asbesto~ workers, who had been exposed to <l~bestm from wrn k. clothes C<lrried home. ,unong populd t1ons near asbe~tos factorie~ and mtnn !lflJ amonf_ peopk who had non-01..::upational .lSOc!>tos expo<;u1 c. ,A,hbr P""-.":'-."..'1a.r,_h. ,,,.r_~.s-ses 1h.. e nc'efcf '01 teguJating asbe~;,1,., '>'.ask lliSp\l:-,di. maintenance and repair of asbe~to~ products JtH.l pruvis10n tf work clothes <lnd lockers in factories so that the worker~ do not go home in r-l.rH ht:1-c-'> keeping the exposure to asbestos \'vithin the pn:'scribed threshold limit, mesothelioma of pleura and peritoneum is difficult to prevent. Measures are, therefore, being adopted in other countries to find harmless substitutes for asbestos. Besides, these countries have also made it statutory to use warning labels on all products containing asbesto) How exactly asbestos causes these disease is not still clearly known. One of the theories put forth earlier incriminated the fibrous nature of asbestos because fibres smaller than 5 micrometres in length or finely powdered asbestos caused negligible effect. But considering there are other fibres, including man-made fibres, which cfo oot pose a similar threat, asbestos hazards were attributed to itiqibrous nature and the chemical properties - A labourer's hut made almost entirely from fibre dissolution in biological fluids dnd liberation of toxic elements like magnesium, nickel and chromium. '> ii' Thf'eShold Umit value As fresm evidence accumulated ab- ...it lhc harrnrui effects, particularly of --:-:.-,, :i':.elioma, the asbestos exposure '.:-:::;~ t= been continuously revised. Cumulative asbestos exposure is expressed as fibre/years per cc and is ohtained by multiplying the average concentration of fibres during work !J(lurs and the length in years of a worker., exposure. It was earlier found that le~s than one per cent of '.he wcrkers developed asbestosis at ,w exposure of 100 fibre/years per cc. Based on this. the National Institute of Occupational Safety and Health \NIOSH), USA, had suggested a threshold limit value for exposure of and a oeak concen- piing, iime of 15 minutes. n1c1m!1, w prevent mesothelioma). In 1970. thi:, was recommended to be reduced to 0.1 fibre per cc with a peak concentration not exceeding 0.5 fibre per cc. In 1980, following the Asbesto~ Working Group's (established by the ~!OS! 1 and the Occupational Safe\\ anc1 Health Association, OSHA. LJS\, finding that there was indeed no sa!L exposure limit, OSHA promulgated '' maximum workplace exposure limi1 of 0.1 fibre per cc. Debates are ab.P going on among the European coun tries about muc; reduced and srrin'gent standards.<..,Meanwhile. occupational health and envir.onmental agencies have proposed a baion all non-essential uses of asbestos. To prevent asbesto~ ealth hazards, the simple and most effective way is to eliminate asbestos by usms asbestos scraps other harmless fibres. A good deal of research is going on elsewhere to find these substitutes. And one such i~ polypropylene wire mesh which ca:-i be used in piace of asbestos for rein forcing cement. Because of its wide varl!Tv of .us.es_ ~rci.~ ::~~!1oT howe~-er. he ea:-.ilv elimmdteJ. Till such time as asbestos is in use. all rne<,sures must be taken to pre\ cnt hMn~ to workers. their familic~ and thu'l who use ashestos products. Within the factory. therdorl workers must be first educated ahnut the healtbi hazards and com.::u \\tJri-practices.[fhe factory mu~t ma111ld 11; good home-keeping, general \\n11L. tion and local exhaust ventilat1-i11 fibres should be mixed in a \\Cl urndr tion and floors swept <111d '>LlllhiiLd with wet mops to keep airhurne fibre concentrations within pre~cr1h<d limits. workplaces should he mclf'I- ~--.._&,- ..r.,.__'~~~~..,...,.,-"'.~~-:-~~~~~~~~~~~....,..~~,7>~~~~~~~~~~~~~~~~~~~~~~.._.~ ~~~i~t:~:;~-=i!~~':~ ~~~~=~t :!:w~ ~:n : : Monitoring. :--~:~i. ;r, b"~O,"r/1,.-..n-:-e: ..a. ,s,bes/los..,(~ibres . ,. ' ~ !HE ~asual COf!~J~ ~~~en, tJW, asbestos fnl.m ~her fi~. Airborne mhalation of ~~~~, fibr~s ~nd the . fibres. &lllaller than 5 micrometres in ma and mesothelion\~ is now fully est.ablished. Th?u~h the increased mortahty from the mc1de~ of lung cancer membrane filter: however. these cannot to be counted using. the currently recommended membrane filter techni- a1 re pba+>e lil,ble c ont an ra d st micros\?_9py is ecooomitfJiJly, tfheea~mibolset de~~;:~:~;:~! ~:~: b~:;c~ug- method for determining airl:50ipe levels -.of a~stos. a'idi the lowest' rdiahle gested for evaluation of airhorne asbestos fibre~ while the airborne samples are collectl'd on a membrane filter and has been linked with<lcl;upational exposure to asbestos, the a~sociation between general airborne exposures and increased lung ~ancer rpo~ta.lity ~as nP.t yet been established. 'flus 1s pnmanly because of the_ low le,~!1 exposure to asbestos, especially ~Ji~n other known ~nd suspected carcinogens are present m the atmosphere. 1';le problem is que with phase contrast microscopv. Electron microscopy can be used f~ir identification and evaluation of such fibres. The use of this technique may not be practical for routine-air monitor-. ing ~nd the results cannot be directly compared to the current permissible limits. Besides.. Lbe significance otwch ~tibre5isno1. yetddiaitely ~- wunted with the aid of pha-;e cnntrast microscopv The current ~tandardi-,ed membrane filter method~ of !tbrecounting developed by the BOHS. NIOSll. the American Confcrenc~ ot 1 Governmrntal lndu~trial Ilyg1e1mt' and the Ashestos lnternation.al A ,,o- ciation (AIAl are more or !e's '1m1br. AA! metho,C wn be used. The \I\ :=i.=::::a::;*~eefl~ .:f:=~==~ compounded by the la!;k of a reliable ~ foe the qiranti!~ive amilysis of ad6me. asbesto;~,,wflen ~-ae presenttbem ~cles~~!ttons tban o r para .. . u~ memu'u now ~men~~j~).PJ>l~le fof_~~- TbCle is a t-enerai consensus 3lllORg ~ 1iall 11a,Jweajgel ....-. Jis!siut pfo.f,.!,,_ef~blL"~i!t~greateuirm . ::5. t!'!Jl!!'# 1fS~-8!C ~ ':foi ~Jibmsis appearing in asbes&obc lnng~ ~ver; ~e is.no sudl :$,Uri.- . of a backgro~d of ~t~r~ias ~.--~~or)d.jg ~P <>.f ~:1oaema- des. ;: : :... , . : ~: , .~ , , .~ , , tmnaJ ~ {Qr ~ardl on Cancer ~e me'~~-"~ fflF~~~ t~-~li,~~et~- }n,;1m~~~l,ud#f~Pl#t:;.fibr~,greate1 winch the,~W~r . p ~t~~r~;- .. tha!.1 .~11.1et~s,u~}~npb :ar~ more greater than"5+ ~~- . 'Jn-{e~~are; ;. :", ,.,~,, Q.dllCUlg t~~!S Tilus the counted was1'~bl . usecfl)Y,ithe .d, ~of Jbe nbre., ~ length and British. ~~#,ill? .,:rgien~.~~t}'. ;moffi!i, }fit ;ar~_;tlt~, tfnti>ortant_ para- (BOHS) 10 th~.s~~Y'.~ran:~bestos t~tile ,m,ete~;~n ~ht;;~ttology 9J 'lung..diseases factory. lt'~:n~w'agr~~~ftltaf.a5~stos ... assci9iit.ed wit4 ~e.x~sure. t0 asbestos fibres are tbeetiofogicaf~ntaminant of fipres. '' , , ,. '.::.: ; . . concem; heq~ Jpe: cilrrently recoin- The setting of varioiis standardS for mended safe ,<air,'}.h>rlcetratlons , and as~stos Jor 'ttie prot~ction of workers' sampling pr~y~s ar~ defined in health w~J>ased on th.is theory and the method is. ho-..ever. used as a n:krencr so th.al r~ls from different ~=be compared. Ot&ermetbods which have been used fus Identifying and characterising the =:~~Ym~~~~~-~31n:~~- fihRs are: infrared spectroscopy, pola- be used for evaluation of airborne asbestos fibres. The membrane filter method, thongh considered to be still the standard )echnique for monitoring asbestos in the occupational envirQ_,nment. is time-consuming and te< ), besides open. to considerable ..:'X- perimental error and arbitrariness in the number of fibres counted. Hence there is a need for ev-dluating asbestos expo- sure by a faster and more feasible technique. One instrument which is capable of giving rapid fibrous concen- terms of fibre. ci>ncentration and not concept that exposure up to ceJtain trations in the air is the Fibrous Aerosol otherwise. Pa\"tkles with"the following levels can he tolerated wlfhout undue Monitor. Model FAM-1 . developed by geometric dimeilsfons 'llJ'e called as fibres: lengtil,grellt~r than 5 mic- risks. In, 1980, both the US National Institute of Oecupational Safety and the GCA Corporation. USA, under contract to NIOSH. The in!>trument ha~ / rometres, diameter less than 3 mic- Health :1NIOSH) and the Occupational been evaluated against the NIOSI! rometres, and a length-to-diameter Safety and Health Administration approved membrane filter sampling ! ratio greater than 3:1. Only such fibres (OSHA) concluded that: (1) there is no technique and the results have shown a Ii collected on the .membrane filter are counted at 400 to 450 times magnifica- safe exposure limit for asbestos; (2) all commercial and several non- strong correlation. The instrument now available in the.market is I tion (4 mm objective) with phase con- commercial forms of asbestos cause trast illumination. The main disadvantage of this disease; (3) a new standard of 0.1 fibre per cc should be used as a maximum ! S. CHAKRAVORTI I Mr. Chakravorti is Deputy Director (Che- .m.et.ho.d i_s t~ha~t it~d~oes~n~ot~di~ffe~ren~tia~te~~w~o~rkp~la~ce~ex~po~sur~e l~im~it;~an~d (~4)-op-tic~- ~~m1_ca:l), .Ce.ntral L~ab~ou-r I-nst-itute, Bombay. I l check 1f the control measures are adequate or not. Workers' health should be monitored through an effective industrial health programme. This programme should include sputum examination for exfoliated malignant cells, lung function tests and full-size chest Xrays. This will help in early diagnosis of asbestosis and lung cancer and inform about the ai1equacy of the safety measures used. Smokers should be discouraged from working in asbestos factories. and a "quit smoking programme" should persuade smoking workers to give up smoking. Workers' condition should also be followed up after they are discharged trom worl. on medical grounds or on retirement. It is also important to protect a worker's job even after he is paid any compensation for asbestosis or lung cancer due t0 asbestos. And all worker" should be provided' with work uniforms and lockers, and proper arrangements for washing and bath so that they do not expose their family members to asbestos. To protect the population in the vicinity of a factory, 1t is essential to pack and dispose the wastes carefully. Other countries use highly trained personnel for this job. All asbestoscontaining products should carr} a warning label so that user-., like gar age workers who repair brakt )ng:.. or ship breakers (asbe<>tos is usc:d for insulation in "hips), take adequatt' precaution and use prutective dev1cc:- while handling asbe<>tu-. Dr Kumar was till re cently Deputy Director (Medical). at the Central Labour Institute, sombay. Earlier, he was a medical officer at Coal India Ltd. After graduat mg m medicine from Bangalore University, Dr Kumar specialised in industria nealtP j at the All-India Institute of Pub11c Healtt. Calcutta. He is now an industrial physiciaio at the Ciba-Geigy of Ind.a, Ltd, Bombay. 46 ')( I: 'j ' TOP<\) Jt L1 J982 /; i '-J t as Barry L WhileH increasi still pr.Q' unregul Aproclaim< en lfOnrr L'nited Health, announc( mainder the next, deaths (c be attrib Des pit health e there 1s ! f~f' "es. ~ p.,, ,.te t days) anc periods ' yet unde1 tos dust i mcreasec esophagt kidneys, has be<'n ence 0{1 and perit eKtent o In sh where as sively us red not worked< among s Neighbo 1es have from am m),""rer g11 ;al veloped many 1 mesoth~I home on X-ray al asbestos Physicia1 Employr 'non-occ hi~.torie me-;othel Compen, The w1 ot the n ha~ had cesults. have 111s1