Document mmq9OM0wRJ1Q2X2Z5VM67ER0d

FILE NAME: Z//E DATE: DOC#: /E DOCUMENT DESCRIPTION:/'ZZZZZdZ^ ,,Z/ c_-,-...--1 G-\J:.: a-~l <?-vr-~ ,_ ~- c-L TABLE OF CONTENTS 'l S.No. I. Preface 2. Summary of observations & recommendations. 3. Report of Study Team 'A'. 4. Report of Study Team 'B'. ,.,..._ Yv'> -''1 I ~ J Page 5 8 21 REPORT OF THE COMMITTEE "TO STUDY THE INDUSTRY" EALTH HAZARDS IN ASBESTOS BY THE DGTD PANEL ON H CONSTITUTED ASBESTOS PRODUCTS INDUSTRY PREFACE nel on Asbestos Products Industry, constituted by Jn pursuance of the decision taken by the Pa tion No. 6-14/81-Cem. dated 22.8.1981, during its sixth meeting held at e formed the Go\'ernmcnt vide its Resolu 83, Department of Environment was requested to head the Committe Mtoa"dSratusdoyn H1e2athlthJuHlyaz1a9rds in Asbestos Industry". The terms of reference assigned to this Committee were : lems associated with inhalation of To sftoorsmfuiblarete ata thperopwoosrakl plfaocre tohre instuthdey goefnetrhael ehnevailrtohnmpreonbt. legislative prov1s1ons for protecting asbe To examine the adequacy or otherwise of existing risk of asbestos induced maladies. occupationally exposed workers from to health and safety in the Asbestos To make other recommendations as appropriate in regard Products Industry. ove mentioned Committee was entrusted to me and it consistec.l of e industry The Chairmanship of the ab wn from research organisations, Government regulatorisy aattgaecnhceides. , th members specially drn and independent experts in the field. The 11:-,t of the Committee members the terms of Committee met for the first time on 25th February 1984 and decided that rc~olvcd into the various areas of study, The de in their Clrntent, could be appropriately r detailed study and analysis. The study teams r,,ehfe1crehn1cne, tubrenin~f!ho\u\ild he alloted to 1wo !>tudy tc,1111; f0 formed & their area> of >tudy are Jetailed below : B. Chatterjee, was asked to study health Study Team'!\', under the Chairmanship of f asbestos Dr. B. fibre dust at workplace or in the general environ- pro blcms associated with inhalation o edical aspects including medical surveillance and diagnostic criteria. ment, covering all m hairmanship of Dr.G.G. Davay, was asked to: Study Team '13', under the C ting legislative provisions for protecting occupa- Examine the addewqourakceyrs ofrroomthtehrwe irsieskoof feaxsisbestos induced maladies. The Team/owtheerer gtuoidesltiundeys tionally expose the Factories Act, Model Rules under the Factories Act, Model Rule 123A d the Draft National Regulations issued by the Government of India, the Indian Mines formation Act an Centre (AIC). The consensus of opinion fworasAthsbaetstthoes fNoarmtiounlaatledRebgyultahteioAnssbsehsotousldInbe exhaustive and specific which are applicable, as a standard, in all the States in India ; Act and Insurance cover. The Cover in depth all aspects of Workmen's Compensation Act, ESI claims of compensation and level of compensation :itudy was to cover the agency tionalized for deciding insurance companies regarding insurance cover for temporary and and the policy of na permanent disablement arising from exposure to asbestos dust. .i liFI .I t i tJl i I,, I l 1.1 "' ~l lI ' I. '~ l \ -1 ' J '1 ! -: 2 Both these Study Teams met independently several times and collected irnro1tant data by v1~111ng mines, factories at various locations and/or by literature search for scientific works on the suby:ct and study of regulations and practices of various countries and international bodies, like, the Il.O. The Committee reviewed the progress of work of the two Study Teams during intcrmec!1a1c meeting-, with useful exchange of technical data. The reports of both the Study Teams have now been recci:n! and after scrutiny by the Committee are placed on record and appended to this report I would like to thank both the Teams for the great effort in generating this important and w;eh1: document and also the members of this Committee for their valuable guidance from time to t11nc I would also like to place on record my sincere appreciation for the untiring efforts put in by Bri::~ D.B. Kapoor, Member Secretary of the Committee, but for whose assistance the report could not hc1\c' heen completed within the stipulated time. I would finally thank the Chairman of the Panel on ;\~bestos Products Industry for opportunity to deal with such an important subject. I believe that the dedicated members connected with this report is amply revealed by the qualitative technical ned in the document. prov1dmg me th11 ~xperLse of all the evaluation contai- I have no doubt that this report will form a useful base document to evolve strategy and plans f,ir the control and elimination of risks in the asbestos industry and other such indLhtries deal111g with toxic materials suspected of long term health effects. New Delhi 9 July 1985. Sd. (D.K. B!SWAS) Chairman of the Corn1111uu: ata h; \ i'litrng 1 n rile ~uh1cct the J/'")_ 1atc ll1cCl1ng'" been received ll and userul to tune l 111 by Brig .luld not havl'. dmg me rh1s ;sc of all the 1tion contai- d plans for dcalrng w1rh Cnrnm1l!ec 3 LIST OF MElVIHERS OF THE COMMITTEE ''1'0 STUDY HEALTH HAZAIWS IN ASBESTOS INDUSTRY'' \Ir DK. B1~wa~ Director, Der:1rt111ent of Environment, (;o\'Crn mcnt of Jndia, B1L1ncr llou~c . Sh,il1 Jahan RoJd, N l'\\' D cIhi- I I 0 0 l I Dr. V.P. Gupta Di rector (Research), Central Labour Institute, Eastern Express Highway, Si on, Bombay-400 022. 3 Dr. B.B. Chatterjee Director, National Institute of Occupational Health, Maghani Nagar, /\hrnedabad-380 016 . ..\. Dr. G.K. Pandey P1 inc1pal Scientific Ofliccr, Department of Environment, Go\crnmcnt of lnd1a, B1kancr House, Shah J,1han Road, ~c\\' Dclhi-110 011. Dr G.G. Davay I \ \!L'i!1,::1l lrhpcct.ir ,,r I :1l'ltlflL'' c;,,\,111111L'f1t "r \l.1h:11:1'ht1.1. 7 72, \':.rma Nagar ( lld N:1garda' Road, .\ndhn1 ( [a,t ). Ht)rn ti.1: -.:ioo om. !1. .\fr. Ci 'i. lchhpurani DDG of Mines Safety. s,)uthcrn Zone, I lydcr<>bad lk SK. Daw .\\>!. Director, 0:ational Institute of Occupational \1aghan1 Nagar, :\ hmcdahad-380016. Health, S. '.\Ir. 13 K. Sharan Director, Mines Safety, Directorate General of Mines Safety, Dhanbacl. Chairman Member Member Member Mi:mber Member Member Member 4 9. Mr. N. Venkataraman M:anaging Director, Everest Building Products Limited, "J\shok Bhavan'', 93, Nehru Place, New Ddhi-110 Ol9. ill. Mr. J.B. Amin Vice President (Works), Hindustan Ferodo Limited, Post Box No. 9213, Lal Bahadur Shastri Marg, Ghatkopar, Born hay-400 086. l l. Mr. V. Pattabhi Asst. Vice President, Hydcra bad Asbestos Cement Producb Limited, Sanatnagar, Hyderabad-500 018. l2. Dr. S.P. \'ivek Chandra Rao ]\1ed1cal Officer, Medical Surveillance, Hydcra bad Asbestos Cemen~ Products Limited, Sanatnagar, Hyderabad-500 01'8. ,1.~\, Dr. P.K. Sishodiya Hyderabad Asbestos Cement Products Limited, Ballabgarh, Fandabad (Haryana). 14. Bng. D.B. Kapoor [xccut1vc Director, Asbcsto"> Informat1on Centre, 401, Padma Palace, 86, ~ehru Place, New Delhi-110 019. ~vfcinlJe 1 ~,,1 e1~1 Lt:~ l 'h~ l j ' :.1 ~rnLt.:~ 1Vlc1n :)c~ \i1:mbct l~ \_ l l 1 2 ', l ~' 1; 111'-.'. l- ')c.:Cl'.~l: ~; 5 Iember SUi\JMAH\' OF OBSERVATIONS AND UECOMMENDATIONS Obserrnfions I. i\lain observations arc 1.1 Uneontrolk<l asbestos usage workers. Such exposures has been the cause of heavy and prolonged exposures to to asbestos dust may result thelioma. (Para 9 of Report by Study Team 'A'). in asbestosis, lung cancer and mcso- 1 2 Tvhaleesnecediosefacsiesscahsacveatloanngy lgaitveennt tpimereio. ds,(Pmaaraki1n0g oift Rdeipffoicrtulbt y tSoturdeylaTteeamexp'Aos')u.re to the pre- nbcr J .3 There are some reported cases of low exposures in the past increases in risk. that resulted in no appreciable of exposures J\ report on the evaluation of risk to miners in Canada on (50 fibre years) is estimated to hav current levels Report by Study Team 'A'). e had no unacceptable risks. Such information enables this Committee to (Para 11 of use of asbestos so that the 111 such places where it can be used under controlled and recommend the regulated conditions workers. benefits of this material continue to be exploited without any undue risks to the bcr I .4 Tinhoerlgaatneisct sficbieronutisfimc athteinrikailns.g fa(vPoaurars1t3heofcRonetproorlltebdyuSsetuodyf Tneoatmon'Aly').asbestos but also other Recommendations 2. General Environment er 2.1 Various studies reveal that asbestos in any detectable increas general environment has not been found to cause e in risk to the people at large. (Para 21 of Report by Study Team 'nAf'l)t.ionaltl ipsr,ahcotiwceesv.er,(Ppraurade2n1t otof Rcoenptorortl balyl SastubdeystoTseraemale'aAs'e)s into environment as per inter- 2.2 Ab<t.:etnhisatpteonindtedofwt1it1hncn, csgtuatdii\e'ts: orensuilntgs.est(iPoanra o2f2 aosfbResetpoos rtfibbyresSttuhdryouTgehamdr'Ain'k).ing water havi.: 2 .1 Stith:irtce dPuosltluitniotnheCognetnreorlalBoeanrvdisrosnhmouelndt.ma(kPeaream1is6s.i1o0nosftaRnedparodrst bfoyr Sttuhdey cToenatmrol'B'o).f asbestos ]. Legislative Regulations. 3.1 Factory Acts & Rules. 3. 1.1 Framing of rules according to l, the Schedule XIV and Model concerned States is an Rule 123A by the urgent rcqu,irement. (Para 16.2 of Report by Scudy Team 'B'). 3.1.2 All operations and places purview of the Factori where asbestos fibre is .used should be brought under the es Act and Rules, irrespective of the size of the workforce or usage of electric power. (Para 16.8 of Report by Study Team 'B' ). 3.1.3 aEsvbeersytopsroficbersessahnoduldeqbueipsmtuednitedreflaotreditstoptohteenmtiialllintgo ocfreaasbteestaoisr-boorreneandduspt.roIcnecsassineganoyf epnrogcineesesr/einqguipcmoenntrtol rmeleetahsoedss,dsuuscth tphraotcecsasn/enqout ipbmeenct osnhtrooullldedbetoptrhoehibdietseidre. d(Pliamrait by of Report by Study Team 'B'). 16.5 3.1.4 Current prescribed level of 2f/cc as specified at the present time. in Model Rule 123A is considered adequate Membrane Filter Technique (MFT) should be used for the measure- ment of the air- borne asbestos fibre dust. (Para 16. I of Report by Study Team 'B'). 6 3.1.5 Measurement of fibre dust levels is a complex subject and efforts should be made tt1 obtain uniformity within industry and regulatory agencies (Para ; 6.3 of Report by Study Team 'B'). 3.1.6 Personal protective equipment should not be considered a permanent solution in place . '!..- : of preventive engineering control measures. At best, this should be :i contingencv ' " ! measure. (Para 16.4 of Report by Study Team 'B'J. 3.1.7 Equipment used in the processing of asbestos should carry a certificate from the mantifa- :~ l cturer that during normal usage as recommended, the equipment will not release fibre dust that will result in any workman being exposed to dust levels higher than th~ 0. \lt l prescribed limit. (Para 16.6 of Report by Study Team 'B'). 3.2 Mines Act; Regulations & Rules ~~r. '"I 3.2.l The regulations and rules made under the Mines Act 1952 need to be modified to bring them upto the International Standards for the control of ashe~tos fibre dust during mi:1in:;, handling and milling of the ore. 3.2.2 Where applicable, the rules under the Mines Act should be modified so as to include the relevant provisions of Schedule XIV and Model Rule 123A made under the factoric~ Act so far as they relate to asbestos fibre dust control. 3.2.3 Asbestosis; lung canccr''and mesothclioma when they are caused by asbestos <;l\ould be notified as occupational diseases under the Min es Act. '.l.2.4 Specialised trained manpower and equipment arc to be provided to ctr.:ct1\'cly monnor the environmental exposures in mines and medical surveillance sy'>tcm ot the mine worker-; 3.J Licenci~g. (Para 16.9 of Report by Study Team 'B'). (l. .., ( .. For liccncing/registration of new units, specific requirements of dust contrr.l to he met by them should be listed out by the competent authority. Licence <,l10uld he issuecl by the competent authority only after satisfying ibclf that such requirements have ~i1read1 been includ::d 111 the project. (Par<1 16.8 of Report by Study Team 'B'). ; 4. Small Scale Industry. Management and control of asbestos dust in the small scale sector or the 111dustry need lcJ he tackled on pnority basis. Major recommendations in this regard are : f.Jna~~cial_ : Subsidy should be given for the purchase of equipment ncec!t'cl for the control ot dust, personal sampling etc. Capital :lsscts under this category should not be counted fur the carital investment clause which determines classification for small scale sector. E11;.:i11ceri11g : A technical cell in D.I.C. or other concerned agency should be directed tt> pool the technology for the suprression/control or asbestos dust and to llelp the Small 'll"cdc lndustry to sci ect and 111-;ta 11 appropriate eq u1pment. Mcasurc/Jlcnt and Hca11h Contr,J/ : The Small Scale lnclu~try shoLtld be encouraged ro fll't.l! their resource~ nnd establish a centralised dust counting centre, as also a health surveilbncl centre under the supcrv1s1on of a competent qualified person. Cd11catio11 : Employees 111 this industry ~hould he made aware of the need fnr strict l'llple_ mentatton of the a~bestos regulations and the health hazard~ that might arise Jue to ,1ct:up:1t1onal exposure to asbesto~. (Para I6.7 or Report by Study Tc.: am '13'). 5. Compliance of Regulation~. 5.1 Pncking nr raw asbestos librc should he. in irnpcrmcah!c ba;;~ and 'ihouLI be: !i:rnd! 1i .ll unitiscd load~ as far as it is practicable. !SI may he requested to bring nut the Ct1d. oJ' Practice for packing, !;:rndling, trnn~port;1tion ~nd use of asbestos tibrc. (P.1r:i !(1 l l 1 r Report by Study Team 'B'). 7 ie made t0 Report by.' ~" rffcctive steps to implement the Rules must be taken by providing all facilities to the stat.: regulatory agencies. These include dust monitoring equipment and specialised trained manpowc1 in order to produce accurate and 1eproduciblc rcsul ts.' (Para 16.3 of Report by Study on i11 ,iace :ontingency :he mnnufaclcasc fibre Team 'Ir). 5.3 The industry should periodically monitor dvst levels to ensure the effectiveness of the engineering controls. (Para 9.2 of Report by Study Team 'B'). 5 .i Gtl\crnment should be liberal in allowing the import of equipment required for the use ll1 d u't monitoring & med 1cal surveillance. (Pam 16.13 of Report by Study Team '13' ). :r than the tt. \ledical Surveillance. (1. l All the \\orkers likely to be exposed to asbestos fibres should be covered by a well ddincd medical surveillance plan with no cost to the employee. (Para 27.2 of Report by Study :d to bring ring mining, rncludc the Factories s shLHtld be monitor the 1c workcb. met by them competent included in y need to be 1e con' trol of Team 'A'). fi.2 H1::ilth education of workers is an important object of medical surveillance programme. (Para 28.l.2 of Report by Study Team 'A'). {;.:; Frequency of periodical medical examination should take into account age, service of employee and his exposure profile which includes his exposure level in relation to action ln:l. (Par:r 29.3 of Report by Study Tean:i 'A'). 6-4 :-..rcdical records along with periodic exposure profiles should be maintained for 40 years after employment or 10 yL'ars after cessation of employment. (Para 32.2 of Report by Study Team 'A'). 7. _Compen<1ation. 7. I ThL' employees covered under the ESI Act should also be eligibk for compensation after cessation of ESI coverage, as is the case in Workmen's Compensation Act, (Para 16.12 of Report by Study Team 'B'). Employees not covered under the EST Act should be covered under general insurance, at no cost to them. (Para 14.6 of Report by Study Team 'B'). 7 ; Clear criteria for the diagnosis of asbestos related diseases. should be specified and should be uniformly followed. (Para 14.2 of Report by Study Team 'B'). Criteria for diagnosis for asbestosis i' included in this report for the purpose of determining eligibility for compensation. (Para 24.l.6 of Report bo Study Team 'A'). Criteria for confirming asbestos as c~Hts ative fact9r for lung cancer and mcsothclioma is also included in.thi<; repot for the purpor;e of d-:tcrrnining digibility for compensation. (Paras 25.7 and 26.8 of Report by Study counted for e directed to Small Scale ~Cd to pl10l ~urveillance strict 1mple. .1e to occupa- Team 1\)'. 1.3 The Committee rccognises the .need to designate an agency that pos>es-;es specialised training, expertise, competence and facilities to decide the cases entitled to compensation arising out of a<;bcstos-related diseases. (Para 16.12 of Report by Study Team 'B'). 7.4 Regional medical panels should be constituted to act as rcferal bodies in case of asbeslosrclated diseases to determine eligibility for compensation. (Para 34 of Report by Study Team ';\'). I .5 Panel should have specialists, preferably with knowledge of asbestos-related diseases. (Para 3-i of Rcpor t by Study Team 'A'). 8 :'\ational Stanclards/Cocles of Practice. IS l may be requested to expedite formulation of: :1e hanJkJ as t the Code of Para 16 11 of Standard for the measurement of airborne fibrous dust. Code of practicc for thc packing, handling transportation, and use of asbestos in the factory, mme and other plac..:~. Code of practice for the use of asbestos containing products. CPdc tll' practice for disposal of asbestos waste materials, including tailings. (Para 16.14 of Report by Study Team 'B'). _,,.._, w-.. 8 FINAL REPORT OF THE STUDi'Yd:ETE"TAOM S'ATU' FDOYRTMHEEDHUENADLETRH THE AEHGAIZSAORFDTSHINE TCHOME M'AISTBTESTOS INDUSTRY", CONSTITUTED BY THE DGTD PANE!.. ON ASBESTOS PRODUCTS INDUSTRY PREAMBLE In pursuance of the decision taken by the DGTD Panel on Asbestos Products Industry to constidesignated as tute a Committe to "Study the Health Hazar.ds in Asbestos Industry", a Study Team terms of reference appended -, Study Team 'A' was formed and was assigned the tasks as appear in its hereafter. The Chairmanship of this Study Team was entrusted to me and I, co-opted members from Governpertise and resou recs the Asbestos Information Centre, with with sufficient ex the health problems of asbestos mtoecnotanltraigbeunteciteos,thInedsutsutdryy aanndd review eanlldataisopnescftsor tchoennmecatneadgement of the major issu;;s. exposure and provide suitable recomm he Team was conscious of the absence of suitable epidemiological studies in this country on ation of the work- T asbestos related prnblems. Sufficient expertise and manpower asb~stos-related required for diseases do the evalu not seem to be available to places and timely and accurate diagnosis of ents in tne country. i:;:xchange of expt.'riences in this field between the Government ula- meet the requirem ngwith a consideration of the existing facilities and practices of this problem, the reg helped the atogreyncbioeds iaens din tthhee idnedvuesltorypeadlocountries, where extensive bweoernk hreacsobrdeeend.donFeoor n achieving this, we have Study Team to identify areas of consensus which have , Health & Safety Executive (UK) rer>rts, NIOSB (USA) reports and utilised publications by the ILO emin~nt s~ientists in the field. published articles by I hope that this report -will be helpful in bringing about a uniformity of approach, practicabk posure to airborne management and reasonable protection of employees at potential risk from ex asbestos dust at their workplaces.- We believe that we have to learn to live with asbestos; a substance that is going to be with us for :itcrials of toxic natur~ a long time to come. In so doing, we. might also learn to beneficially use other se, at the same time, m contaming their harnrds while deriving social benefits accruing from their u adequately. The co-operation and contributIiosnincoerfealyll wtihshe tomtehmabnekrsthoefmt.heI Mmer.toDb.Kri.ngBioswutasthoisf trheepoDrteapnadrtment of Environment for providing such a competent team of experts. Study Team mack it possible for would particularly like to thank me with this opportunity to lead 27th June 1985. Sci. (Dr. B.n. CH/\TTERH E1 CHAIRMAN OF STU fJ\ TEAM 'A'. 9 I !~AL REPORT OF THE STUD\' TEAM 'A' FOllMED UNDER THE AEGIS or THE COl'v1MITTEE "TO STUDY THE HEALTH HAZARDS IN ASBESTOS J:\DLSTRY", CONSTITUTED BY THE DGTD PANEL ON ASBESTOS .> PRODUCTS INDUSTRY. Ttrm<> of Reference 'J i:c t<-rrm of rcfrrcncc assigned to the Study Team 'A' were to: .., , S:udy hc~1lth problems associated with inhalation of asbestos fibre dust at workplace or in :he general environment, covering all medical aspects including medical 'surveillance and 1'.1.::'n,,,:,c criteria. In case the Team felt that it was not in a position to study in detail '.i.c pr,1h!cm of general environment, it could prepare an 'approach paper', identifying areas ,,f ,:ucly by other agencies, giving recommendations thereof. , ;, 1 l".wc:r in depth all aspects of workmens' compensation Act, ESI Act, and Insurance cover. The Study should cover the agency for deciding claims of compensation and level of ctr:;pcmation and the policy of nationalised insurance companies regarding insurance cover 1,ir temporary and permanent disablement arising from exposure to asbestos dust. L:-:J::r th:: second term of reference, the Team considered that the following subjects were rn th: ;-':i,vi::w of the Study Team 'B' : i;; 1 Thi.: agency for deciding compensation. it) y be kv<:l of compensation. 1c1 f\>I icy of the nationalised insurance companies 'regarding insurance cover for disablement .1ming from occupational exposure to asbestos dust. Tlnh, the Study Team 'A' decided that it may make recommendations only on the following ;"pn:ts under the second term of reference : Compo,ition of the panel to decide the eligibility for compensation. Criteria for diagnosis of occupational asbestos-related diseases for the purpose of comp.:n-,.1tion. "tuJ1 1 .. am ':\'and its Action Plan I'' Study Team 'A', comprised as under, was constituted by the Committee "To study Health ii.:t.:r1h 111 :\sbcstos Industry'', during its first meeting held on 25th February, 1984, in the Depart;~;~ni .:f J _nnrunmcnt, Bikaner House, New Delhi : 1.1' Dr. B. B. Ch attcrjee ..,~ f)~. CJ.CJ. Davay '' D:.\'.P.Gupta ~:. i)r. ~).K. Dave -. D: (i K 1'.1mky i: \fr :\. \'cnkat.1raman .,; \lr J B. :\min f; \ir \". 1';1ttabhi ' 1 Dr S P. \'ivek Chandra Rao , U Br1~ D.B. Kapoor Chairman Member Member Member Member Member Member Member Member Member 10 .7.1984 and at New Delhi on 31.1.1985. During these in India met at Ahmedabad on 21 scientific knowledge available on the subject boththe industry 4. TmheeetSintgusd,yitTweaams decided to reviewreptrheesentation was given to the regulatory agenteccihesniacnadl papers, such and abroad. In the Study Team, n to contribute relevant technical information. Various the Health and Safety Execu- which were in a positio e Advisory Committee on Asbestos constituted by lth and safety, arising fiom the use of as, the reports of th UK, & the Ontario Royal Commission "On matters of hea onal Institute for Occupational Safety and Health te, tive, and recommendations of tthoeaNsbaetsitos, papers published by the Asbestos Institu blished hy u a(sNbIeOstSoHs"),. rUev.Sie.Aw. on workplace etixopnosAurgeesncy, USA and other relevant liteTreaatumre inp formulating Montreal, Environmental Protec scientists have been taken into account by the Study eimts ionbesnetrpvhaytisoincisunasndanddrawing up recommendations. o. Asbestos and Health silicate minerals, is limited in commercial use to 5. Asbestos, a generic term covering fibrous rysotile, crocidolite, tremolitc and mixtures thereof. , amosite, anthophylite, cb crocidolite to a much lesser extent. actinolite s chrysotile the most, tremolite to some extent and an and Karnataka. Chrysotile is presently 6. 1InndIinaduiase, tremolitedhisrapPrirnacdiepsahlly(Cumdidnaepdh)i.n Rajasth 3000 products, tht.: mined only in An bject mentions about the usage of asbestosminanouvfearctured in India. Most 7. While literature on no the su information as to how many products arc actually ucts and vinyl tiles whereas industrial StudyfiTcaenatm nhoans-industrial end use is in asbestos cemmaetnetriparlosd such as hrakc linings/dutch facings (l3TA) signi ation products, textiles, friction asbestos fibre (CAF) jointings and beater addition uasneds ginasckluedtienginsmulaterials like compressed jointings etc. d in the U.K. as a form of pncumocon10sis h.rmccl sothcliomu 8. Asb~stos-related health issue was first identifie entified as an occupational risk related to asbestos. Mc l 960 "* 11 wa 0 then asbestosis, then lung cancer was id ausally related to exposure to asbestos dust since ctories. It was Liter found th,1t bas been shown to be c sbestos & health' problem was limited to only fa ing trades and in ship hui!dmg formed the twhoourkgehrts thematp'laoyed as insulators in tl\e indussetdry farniadblbeuiladsbestos products outside factory setting-;. exctmrlc :--- prone groups where ith they u high health risks are not prevalent in India, for Shiegvheerastl orifskthese applications w ting the buildings, using sprayed asbt'.stos insulation. (a) Insula panels for building comti uction. w drn~it; ( b) .friab!t: insulation ilding mJustry Wt'. have, might havt.: used some lo 1t is conceivable that whataslitt.tle S'uhciph fbaucts need to be obtained. usu;~Jly asbestos insulation in the p sbestos magc in the r.ist resulted Ill proL)nge<l and rebtcJ tu u 1e ':>. There is little doubt that uncontrolled a to workers. The ~cvcrity of t.:xposurc, obv10usly, n. IS hcehaoviyceasabdeosptotesddufosrt perxopcoessusmregs of fibres und the kvd of precautions take t periods of a~bcstos related discas.:s- :\sb&cst1o\sf1rssuglhecneIiru"t1:1Iu: 1 There is a consensus about thpeoslounreg tloatmenanifest; Lung Cancer ovt.:r 15 to e2x0pyocsau,rses wiL11 conliJt:nc.: taking over 10 years after This ex phenomenon makes it difficult to relate thc today are the rc-;ults over 30-40 years. revalence of the diseases. The diseases seen of conditruns tgoentehraellycuprnre:vnatlepnt in the pre-regulation era. ** Sleg~s, C.A. & Marchand, P. (1960) Brit. J. lndustr. Mt.:d., 92, Page 21.) Wngncr J.C. Report of the Advisory Committee (UK)-Vol. JI., Pam l 7, 2(1() (Final I lJ Ul ~r; Iii .._];\ I'i' l i ,1 I . I. I: " " lndi:i J.irn 1 - g these in I n(,_..1 indu ~rs, suc11 f Execute use of d Health ns tit utc, shed by mulating al use to :r extent. presently hicts,the J1a. Most industnal :h facings n (BTA) ,1s termed othcltoma was then n1nd that ormed the )' sctttng'. c :~ .nd usually ed to the: .s gcnna:Jy sothcl1om,1 conlidenc..: conditions 2(,() (Final 11 11. Due' to the same reasons, it is also not possible to accurately predict the level of these disease'> in the years to come when the effects of regulated asbestos usage will be known. However, some ~t;1t1'>tical predictions indicate that controlled use of asbestos should not give rise to any unreasonable ri'>k. Based on evaluation of J.C. McDonalds' Study of miners, exposure of 1 f/cc for 50 years ,1iuuld not cause any detectable Asbestosis and the risk of lung cancer is exp2ctcd to be equivalent 1'..1 ~moking 3 cigarettes per month.** l he nccc,sary precautions that have already been taken in the Western countries have virtually cllfn1n~1tccl gross Asbestosis that led to early deaths in the past. for example, no deaths from As- lo:_ -,t('\J'> !:ave been observed in the men and women who have been studied m an asbestos textile :.!.:"r~; i11 Rochdale (UK) who were first employed after 1950*** J: ;, :11'0 to be noted that the latest scientific tl1inking favours controlled use of all inorganic L l-rnu<; matcnals, not JUSt asbestos. This precaution is necessitated by the fact that several fibrous ifl<'l!~.intc ~ubst anccs have also proved to be carcinogenic in experimental animals. These have not hcn suflic1ently studied, nor have they been, in some cases, in use long enough to evaluate their '-i"'lt.:miologieal long-term effects. 1.: '1 LL'fc: are countries that arc formulating regulations to cover all fibrous materials usage. In this ,,>ntc.\t, the ILO has prepared a gene.ral Code of Practicc-"Occupational exposure to airborne ''11 1\;,tancc<; harmful to health"; 1980 (ISBN-92-2-102442-3). lndi:in Studiei, '~ ( >:i!~ :-on:c cross sectional studies of certain factories in India have been carried out, which arc .::qcior;dory in nature. They served the purpose of bringing awareness in the industry and persuad;:1,,: :ill concerned to take effective measures. We have no national data base on which to make an ,,.,,o,!li..:nt of the impact or cisbcstos related problc111s. In the same way, we cannot, at this time, t'.,c1dc tile cxpo>urc limits related to our 'dtings. Under these circumstances, it is prudent to .,ccq'I tltc lc,sons dra\\n f10m extensive work that has been done in the developed countries and :tclnpt the regulations they have formulated which wilt perhaps result in more than adequate r'~0tcction. J.imitntions of the Present State-of-Art U.. r:i: StuJ:- Team r.: ...;;n1>n t!lc fJct th.!l the dust measurement by Membrane Filter Techmque '.\FT; .. :-hl ph."r lntr.i;t m1t:ru\Cllj1Y represent the bi:st current state-of-art that can be routinely :.-;;J ~') Ilic inJu,try. J :.er: 1\ 1:,1 p.1thognom1L k.tturc specific for asbestos related diseases. An individu::il -,,., :<>be b.l<J c'~cntiall) on occupational history of asbestos exposure. diagnosis r ::, :nclthiL>n of the probkm of the presence of asbestos in the general environment in the terms , i r,-f.:r..:ncL w:t> dis<.:L1''>Cd by the members of the Study Team 'A'. 1 :\,b::sto~ i~ ubiquitous and is found in the water, soil and air due to natural geographical erosions. l1 ..!1;,tri.tl ;1,11vity & technical usi: have added to these levels significantly, more so near the :::::.:-,, m.111ufacturing ~1tes and the waste dumps. .\ld)\lllald J.C. :ind Liddel, F.D.K.-"Mortality in Canadian mmers and millers exposed td dHysottlc:" Final Report of the Advisory Committee (UK), Vol. II. Para 202, l'Jgc 40. ... Hxport by Richard Doll & Julian Peto to Health & Safety Commission, U.K.-"Asbestos-- Effccts on h~alth of exposures to asbestos" (Page 3 I, Para 2). 12 20. In isolated instances, problems may have arisen in the v1cm1t1es of asbestos mines, city dumps industries using large quantity of 01 discardea building materials and in the neighbourhood of relessly. Barring a few older rcfercrces to the occurrcnct: asbestos and disposing their solid waste ca amongst population in the neighbourhood of an ashe~tos mine in of environmental mcsothelioma South Africa, there is no evidence of similar problems elsewhere in the world. 21. Information gathered from various studies made in developed countries ,.eveal that table increase in risk to asbestos m the gener.'.11 the general environment has not been found to cause ol the release any detec of asbestos into the environment particularly public. irH. oAwdehveerre,nietei'stoprinutdeernntattiooncaolntrregulations in the disposal of solid wastes and st,1ck emissions in the a is essential. It is also a good practice to plan for maximum recycling of asbestos wastes. 22. A number of studies on ingestion of asbestos fibres with water or beverages have bfen conducted in the developed countries and been attended with negative results. 23. Further, the approaches for quantifying population exposures to asbestos from the genera t of the population arc so difllcnlt environment and relating them to felt diseases that they amongst were not the members equipped to make any pronouncements on the tshuabtjetchte. S1ttuwdyas1aelasron nmoetemdbtehrsat trheecroemmhaesndbsetehnatnotheinpdirgoebnleomuss eoxfpearsibeenscteosoninsttuhdeieasmobifetnhtisennvaitruorne-. of the Department of Environ- TmheentSbtuedsypeTceiaamlly 'Astu',dtiheedrebfyorae,teaminocflusdcieenintisittss fuineldderofthsetugduyidtahnecheealth problems relating to other ment itself. This team should also rally occuring non-asbestos fibrous minerals, such as, the zcolitcs, the abundance of certain natu n reported to have given rise to rnl.'.sothelial tumors in the varieties of which in the soil has bee population, heretofore thought to be specifically associated with asbestos. Criteria for Diagnosis 21 24. Asbestosis Asbestosis is a form of pneumoconiosis, characterised by diffuse fibrosis of lung ;:iarcnchyma, as. It is a non-infectiom, a result of exposure to respirable airborne taesdbewstioths fdiubsrto,sifsorofa lpolnegurpae. rioTdh. e fibrosis is irrcvcrsib!t: naonnd-mthaelipgrnoacnetssdiosfeafsiber.osilst misaoyftoern masasyocnioat progress even after exposure has ceased. Asbestosis is a dose dependent disease. The time between first occupational exposure te, asbestos dust and establishing diagnosis of Asbestosis is usually above 10 years. 24.1 Criteria for Dignosis 24.1. l E~posure Histor~ There should be an evidence of sul;Jstantial occupational exposure to asbestos dust. 24.1.2 Clinical Features Both signs and symptoms of Asbestosis are those of diffuse fibrosis, and hence these are not specific diagnostic features. intcrsUi<d pulmonar;. 24.1.2.1 Symptom 24.1.2.1.1. Breathlessness Progressive breathlessness is the main but a non-si"-'citic: symptom of Asbestosis. Initially, brca th les~ncss occurs on ex1,;rtion. As breathlessness is observed in various systemic disorders, all possible causes must by excluded before a provisional <liugnosis of Asbestosis is mntle. 11ps f 4' of llCC ; In .- In cm\ arly ions. 1ctcd leral lcult 1 the tu re. ironiron- ~ther :rtain l the ma, as ~tious, ~rsibte re to mo nary -specific ;s occurs systemic )cfore a 13 z4.1.2.1.2 Dry cough & chest J>ain. 24.I.2.2 Again, these symptoms are non-specific, infrequi;:nt and are likely to occur late in the course of the disease. Hence, these symptoms are of little diagno.>tic significance . 24.1.2.2.1 Crepitations. The earliest clinical sign of Asbestosis is the presence of persistent bilateral basal and/or infra axillary end inspiratory crepitations. Even though they are bilateral, they are not necessarily equal on both sides, But, this sign too is common to many forms of interstitial fibrosis; hence, not specific for diagnosis of Asbestosis. However, when not accounted for by any other cause and when heard on atleast two occasions a few months apart, given a history of exposure and radiological evidence of dust disease, they do provide valuable confirmation of the diagnosis. Further, this is an important sign as it often prccedts abnormalities in the chest X-ray & lung function tests. 24.1.2.2.2 Clubbing of Fingers. Finger clubbing, a symptom of chronic cardio respiratory ailments is of relatively rare occurrence in Asbestosis. It develops slowly and may be observed in the late stages of Asbestosis. A rapidly developing finger clubbing, particularly if painful, in a person with Asbestosis suggests supervention of Lung Cancer'. 1-t 1.3 Radiological Features. 24. \ .3.1 24.1.3.2 in Basal diffuse interstitial fibrosis is the characteristic change recorded in Asbestosis. The change is more often bilateral. The shadows described are irregular. reticular or linear. For diagnosing Asbestosis and also for comparison of films, a postero-anterior chest radiograph of good technical quality and of full size should be taken. It should include the thoracic inlet and both castophn:nic angles, taken deep inspiration, so that diaphragm lies below the fifth rib anteriorly and the tenth rib posteriorly. 24. I 3.3 The parenchymal changes on the radiograph are classified using the ILO International Classification of Radiographs of Pneumoconiosis (1980). Under this system, the irregular or linear shadows are described as follows : 's' type shadows-width upto l.5mm. 't' type shadows-width over l.5mrn and under 3 mm. 'u' type shadows-width over 3mm and upto lOmm. The changes may be of such profusion so as to obscure the normally clear margins of the bronchovascular structures. Small regular opacities (p q r) may also be present. In advanced cases of Asbestosis the sharpness of cardiac and diaphragmatic borders 2.\.1.3.-1 may be obscured. Pleural changes like pleural plagues or transient pleural effusion or pleural thickening arc usually the radiological indicators of asbestos exposure but not of the disease. These changes need not be associated with parenchymal fibrosis. More often these '.!4. L3.5 changes arc bilateral. Other causes of similar radiological changes must be carefully excluded prior to making the diagnosis of Asbestosis. This is more important in the early srage; of the disease 14. 1.3.6 \\hen the radiological changes are slight. \Vhere possible, comparison of the most recent chest x-ray film with earlier films of good quality is highly desirable. '-."~ -~ . ' '' 1 , :' I 1 14 24.1.4 Lung Function Abnormalities. those of restrictive lung disease. However, occupati- alities in Asbestrtouscitsivaerelung changes are noted in smokers, The characteristic abnorm both restrictive and obs charateristics of . recorded onally exposed to Asbestos , FEVl and F E V 1/ F V C percentage should be cted over a number L1 etry recordings, ie, FVC omparison of periodic lung function tests tion condu compared to the standard 24.1.4.1 Spirom periodically. is of A c much greater value than a single observa of years predicted values. ment or previously measured Jung function results, absence of pre-employ sidered for comparison.** In assessing the and the effects of Hvaolwueesv,erp,reinditchteed valuesadaerefocronage, sex, height, ethnic differences allowance should be m habits. diagnosis of Asbestosis, it is not smoking pattern is consistent with the 24.1.4. 2 sWpehciilfeic ato rtehsitsridcitsievaese. assessment of restrictive lung diseases, like, be empty- 24.1.4.3 More sophisticated measuremer natnsdinlutnhge compliance, reduced rate of lower tial for lo the surement of transfer facto lly helpful as further evidence, but arc not essen routine mea ing, are diagnostica surveillance of asbestos exposed workers. medical 24.l.5 Other Investigations (non-essential). 24.1.5.1 Asbestos Bodies. ginous (asbestos) bodies in the sputum is sis. The presence of ferru sbestos dust but arc not diagnostic of Asbesto exposure to a only an evidence of 24.1.5.2 ~ rarely a justified procedure Biopsy is justified when an asbestos exposed ic curable ung disorder or a thorac reason. for the diagnosis of Asbestosis. It is 01:!1 ring from a suspected to be sufTc the worker for any worker is operation is conducted on 24.1.6 Diagnostic Categorization. riteria for Asbestosis are as given below 24. l.6.1 The main diagnosigtincifcicant exposure for at least 10 years. ory 1/0 or Jbov.:, !LO (a) History of s ures consistent with basal fibrosis (categ niosis). (b) Ra9d8i0o)loCgliacsasliffircaattion of Radiographs on Pncumoccroepitations. ) (1 Characteristic bilateral infra auxiliary or basal ith at least some fee.tun: of rcstnct1ve (c n changes consistent w sbestosis". (d) Lung functio syndrome. criteria would sugge'it "A he above mentioned four (c~ or (dJ would 24.1.6.2 ihe presence of all t and (b), mentioned above, alongwith either 24.1.6.3 P r e s e n c e Porfocbraibt el er i aA(sab)estosis". itions suggest " to repeat that other clinical cond cluded. giving ris.: to simiLtr ncl:o- 24. 1.6.4 Jt must be necdlt:ss and Jung functions should be ex 0 yean aid, logical ion"Tests for H(PeareltdhiycteInddiFaonrmMu:leane)"15b-4y S.K Jain & ** Normal Standatds of Pulmonary Funct Regression Equations. Com. pRaarmisoianh, oIfndD. iJfofeurre. nMt ed. DReetse.rm57i,na8nAtsugoufsYt,cn1t9i6la9t.ory 'norms' in Healthy Men abovi: id T.J Age, Height & Body Weight ors- Ind. Jour. Med. Res, 55,599. years age; same auth -... ever, ,,... 1pati- ,rded mber id a rd ction :suits, :ts of is not ~,- ,. like, mptyrntine ICC Of sonly rom a or any t:, !LO trictive = would rad 10- trs old, . Jain & JOVC 40 15 :.;_ l. 7 C'onclu~ion. The art of diagnosis is always a matter of weighing probabilities and possibilities and looking at the total evidence. This demands expert judgement based on the interpretation or the above criteria. Incorrect diagnosis may result in unfounded socio-economic and psychological damages. Moreover, it may resul,t in treatable diseases remaining unattended. Luni: Cancer. :5.1 Lung cancer attributable to asbestos does not generally occur untill several years after the initial c.:xposure, similar to other environmental carcinogens. >.l EpiJcmiological studies have shown that the risk of lung cancer is greater at higher levels of :ishcs:o~ exposure. Even so, the non-smoking asbestos workers are at less risk of contracting lung cancer than cigarette smokers in the general population. :s J Certain Western epidemiological studies on workers who are occupationally exposed to low levels of asbestos dust concentrations have not shown lowering of life expectancy or excess mortality from lung cancer.** This suggests that regulated and controlled usage of asbestos m;'I}' reduce the level of risk to even to those of the general population of same socioeconomic level. : :'..: There arc no specific features by which an individual case of lung cancer can be attributed c.C'ldy to asbestos exposure. A peripheral cancerous lesion of the lung, particularly in the lower zone in an asbestos exposed worker is likely to be an asbestos induced lesion, more so in the presence of Asbestosis. Examination of sputum for the presence of cancerous cells is able to reveal existence t)f cancer, even in the absence of symptoms and signs, in a proportion of cases. :::.5.6 L:itcnt period for lung cancer in an asbestos exposed worker is above 15-20 years. 2>. 7 It is recommended that lung cancer in asbestos workers be accepted as a disease caused by occupational exposure to asbestos, provided that- 25. 7. I there is a clear and adequate history of atleast IO years continuous occupational exposure to asbestos or there is an adequate history of asbestos exposure of atleast JO years back and 25.7.2 it is found in the presence of asbestosis or bilateral pleural thickening. '\tnothclioma. ~~'. l D:ffu~\'. malignant mesothelioma of pleura or peritoneum is a rapidly progressive fatal di5casc. In the general population it is rare but its prevalence in a>bestos exposed worker~ is recorded to be more frequent. ' " l.:1ti:nt pcri0d for rncsothclioma is generally over 30 years from first occupational exposure :o J ~bcs!Os. "furthcr follow-up study of workers from an asbestos cement factory" by H.F. Thomas Et .;l: Briti~h Jour. of Ind. Med. 1982; 39: 273-276. \f,;.:t;.dJty of workers manufacturing friction nMterials using asbestos" by G. Berry & M.L. ~~-,1:;.)usc---British Jour. of Ind. Med. 1983; 40: 1-7 . "fo:~l.,l;.;r.o;:c of do1.c and t:.~.Jnuf.a.turn1g" by Hans -i.'J).:. 1979. fibre Weill type on respiratory malignancy-risk in asbestos cement Et al; American Rev. of Resp. Disease; 120 (2): 345-354. 16 26.3 26.4 26.5 26.6 26.7 t plays no role in the genesis of mesothelioma. tonial mesothelioma and non signi- Smoking habi ies have recorded virtually ysnootilpeeerxi posed workers.** ss Epidemiological lence stud of pleural mesothelioma in chr vary from massive effusion to gro ficant preva es of pleural mesothelioma may aried histolo- Radiological featur pleural thickening. at autopsy. But again, mesothelioma has v Diagnosis can be made ats bgiroepastydoeral of expertise to identify it. the causation of malignant gical features and require riorite) have been definitely associated with possible and Fibrous zeolites a in (E human beings@@. There is a list of als-these are : probable agents known mtoescoatuhseeliMomesothelioma in experimental anim 27. 3 2:-: Pre An to: 28 26. 7. I Possible : Glass fibres Aluminium Oxide Attapulgite Silicon carbide Potassium titanate Wollastonite 26.7.2 Probable : Pleural tuberculosis Beryllium Radiation worker the disease is deemed to hfaovlelobw1enein~ hen Mesothelioma is fo.md in an asbestos he purposes of compensation provided the 26.8 W d by asbestos exposure for t tinrous occupational ccaounsdeition is met : a clear and adequate history of atleast 15 years con .l There is re to asbestos 26.8 exposu or first exposure to asbestos and minimum interval of 15 'years between 26.8.2 aTphpeeraerainscea of Mesothelioma. Medical Su1vei1Jance Level*** sh0uld be kcpr 27. General lly exposed to asbestos fibres above the Action ends that, presently in India, wt: ma\ A'tl persons potentia ical surveillance. The Study Team recomm 27.l under med set 0.50 f/ml as the Action Level. M J Cardner published by trol limit for asbestos" by ED Acheson & ge 16) "Asbesto&s-StahfeetycoCnommission, UK, 1983 (Para 107-Pa BARIS YI ct al Ann. Ny. ;\caJ Sci; J0"7'.J: Henavltihronmental mesothelioma in Turkey" by H::mntul lJ, (ji'({i' "E 3JO : 423-432. upational Exposure to Airborne Substctr1ces *** The !LO Code of Ps rAaccttiicoen L"Oevcecl, as under : the working environment Health", 1980, doesfuirnee of \V.orkers to airborne harmfusl dsiusbtisntcatnlcyebs eilnow the exposure limits and or all nA level of exp ined by the competent authority. It i level do not usually necessitate application for cxpusurcs n d ': tcoonbseeqdueteenrtmly exposures below atmheplaecttihoose of a medical nature often ~r:et qourirebelow b!f of the tho preventive measures, for level. ex The action level will generally lie exceeding the action 'vnosure limit". ltisto\,-,_ lign:rnt k!iOWU ~been ow mg ;; ltiona: is and kept ~ rnay ----: ed by' 1979; 19. \ti to metlt ,. ud )f .Lll ;ur~s r the 17 :.'. clii c:d ;,urve illance sllould be ti0 n ~ho~ild, ~o t'ar as is practic provided at no expense to the cmploye1:, and medica Medical surveillance able, programme be conducted during working hours. l en! 1rn- (,:) Pre-employment medical should consi3t of: 1_b) Periodic medical examination. examination. ((cd: J) Miv!cc<dliicsaall cRxeacmoridnsa.tion at cessation of employment. (c) JI ca!th cdu.::ation. r H'-lmployment ivtedicai Examination. A rncJical examination w a ;1l:icc of wod: of the worker should take place upon r involving exposure to asbestos dust. ecruitment or prior to assignment 21'( J <2_hjl'Cti Vt:S. or '28. l.i To determine sure to any condition which would be a contrn asbestos; examples arc: the worker wJh -indication to markedly reduced occupationr.I expo- apbrendoircmteadlitvyalsuheosu(lFdVbCe apnredvFenEV1 %)**and the worker with a groslsunrgadifoulnocgtion tl1an asbestos. The worker with ted from joining chronic bro work entailing potential ical ll111g exposure to impairment, gross chest wall nchitis, asthma, abnormality, active bronchiectasis, gros~; cardiac be employed in below 18 years a place of age where should there is a or inactive potential exposure tuberculosis should not not be employed for such to asbestos dust. workplaces. Persons 28. l.2 To educate to asbcs1o~, and advice workers about the health hazard precautions ttohebeprbcvkeenntivb)t'..:/tphreoteemctipvleoyme easures providesddubeytothoecceumpaptliooynearl aenxdpostullree 18.2 28.1.3 To establish baseline medical records e. for furth Structure Prc-e!llployment Medical Examination er surveillance. The pre-assignment them m exposur medical examination of workers w 28.2. l e to asbsctos dust should a case histo include : hose work is likely to invol?e on the ry which int.:ludes respiratory system the occupational history of the worker wi dust, especially asbestos , and previous smoking occupational history; exposure th an emphasis to fil>rogenic industrial 2b :2.2 28.2.3 JOb detailJ a gen that could allow reconstruction of the pas 18 .2.4 eral physical examination, with an a full sized p cmphasi& on ttheexpcoasrudrieo-prcrosfpiilreas for study; osteru-anteri0r chest radiograph to be obtained and tory inter system; most recent lLC guide-lines and :28.2.5 spiromctry, 111 order to preted using the and forced expiratory obtain representative volume in one forced vital capacity (FVC) measurem :-.:oTF : Jn addition, lung function tests second (spirometry (FEV1). cutiv1.: years to establish a more ) should be reliable baseline done every year for data ents first two consc- l'eriHiicis'.\olbcsd1i.c:arvlcEd xianmthineasteiotnes. ts, a repeat test should be done afte.r siIxn mcaosnethsanoyf sgercoossnddtieffset.rence 0:1jrc.~. ::-J. ! . I To detect the earliest signs and symptoms of asbesto :.'i. l.2 To detect the earliest signs presen and s related diseases. symptoms of a non t a si;nilar picture of interstitial fibrosis, and -occupational ad vise the em illness which could pl -:T9. l.J To record any significant change in health status relative to baselineoyee according!:,. :iblt.: 1-Norm<il Standards ) <:;trs old : Comparison of Pulmonary Function Tests observations. J;,in & I.I. Ramiah: Ind. oJof udri.ffMereedn.t RRese.gr5e7s,si8onAuEgquusatti1o9n6s9.(Pfor::e- dHicetaioltnhyFoInrmdiualnaeM) ebny S15. --KtO. 18 29. I.4 To continue to educate & advise' management and employees about health risks, to minimize risk. and to ascertain that appropriate preventive measures are being taken 29.2 Structure of Periodic Medical Examinations. Periodic medical examination of persons potentially exposed to asbestos. dust should include : 29.2.1 a rclevent, brief medical and occupational history including smoking habits; 29 .2 .2 job details that could allow reconstruction of exposure profiles; 29.2.3 a clinical examination, with an emphasis on the respiratory evaluation; and interpreted using the 29.2.4 amfousltl rseizceedntpIoLsOterog-uaindteelriinoers.cheTsht erafdiniodignrgaspharetoto bebe ocbotaminpeadred with those of previous 29.2.5 cshpeirsot mraedtrioygtroapohbst;ain a representative FVC and FEV1 for comparison with previous J11e:.JS- ured values; tests as necessary for diagnostic purposes, particularly in workers with sign~ 29.2.6 additional and symptoms suggestive of asbestos-related diseases. 29.3 Frequency of Periodic Medical Examinations. re profile, should have his first periodic medical 29.3.1 Every worker, irrespective of his exposu ne, five years' after pre-employment medical examination. Thereafter, ction examination workers who do are occupationally exposed to asbestos dust level which one every is more than three years, A Level (0.5 f/ml) should have periodic medical examination d re to Airborne Substar.ces Harmful to 29.3.2 The ILO Code of Practice, "Occupational Exposu exposures to dust levels below the Action Le\'el do not necessi- Health", 1980 mentions that pplication of preventive measures of a medical nature (Para 27.l above refers). ests that this tate a However, as a matter of extra precautionary measure, the Study Team sugg done, every ten years. category of workers should get medical examination ducted more frequently if the occupational 29.3.3 Periodic medical examinations may be con ssary, based on the findings of the previous medical exam1t1at1cn. physician deems it nece Needless to mention, a more frequent medical examination is justified unly to confirm a suspected case of asbestos-related disease. :ll l -~I J 1 3 '.., ,\Jed -~ 1 30. Interpretation. 30.1 Radiographic Evaluation. exposed to asbestos dust should be based en 30.1. l tRhaed"ioILgrOap1h9ic80evInatluerantiaotnioonfalthcelawssoifrikceartion of radiographs of the pncumoconioscs" 0 1 anv subsequent revision thereof. ian may ask for additional views of the chest. like, lateral or 30.1.2 The occupational physic oblique, in selected cases, for further information. 30.2 Pulmonary Function Evaluation. which provides a trai.:ing of volume-flow or volume-ti111c For recording FVC, FEV1 a device ced expiration is recommended. The tracing should be stored & availa- curve during the entire for ble for recall. rccOl'ding FVC and FEV1 the technique should be properly d..:monstratcd and 8 minrrcutr e out of lhcsc should While of three acceptable manoeuvres should be performed and the maximum valu (Jf that ethinic group for comparison is an approxim- be recorded. Predicteedavbasleunecseoofflupnrge-feumnpctliooynment and periodic medical examin,ttion observa t 1orh sary for ation accepted in th in the older employees. Additional examination of respiratory function may be neces cvidcnc~ of respiratory symptoms or f'llllcir~nal appropriate diagnosis, particularly in sub_kcts with impairment on spiromc~ry. and to le : sing the previous is meas- ith signs medical 1ereafter, n Action [armful to )t necessi'e refers). that this cupational amination. confirm a based on ~s" or any lateral or volume-time cd & availaa minimum these should an ap;Jroximobsct vations neces~.iry for or functional 19 >I. l Upon the cessation of employment, a full medical evaluation including review of all investi- gations done during periodic medical examinations should be performed. .' ! .2 The employcr ~hould arrange for the medical examination of the employee within 30 days of termination of employment. ) 1.3 At this medical examination, if the worker is suspected to have any abnormalities related to :i~bestos, he may be called for further periodical medical examinations. A copy of the pertinent findings of this medical examination should be provided to the worker at this t:mc. .\~rdlcal Records .".1 1 ~lcdical records should be maintained in accordance with good medical practice, ecognising the long latent period for asbestos related diseases. .~: '} ~kJical records should be maintained/stored for a period of 10 years following C,e terminat:on of employment, or for 40 years after first day of employment, whichever is later. : : :; :'.kdical records should include the details of pre-employment examination, the periodic medical examinations, and the medical examinations conducted at other time, if any. ! ~ .! :\s part of overall medical record, records should also be maintained of the individual c mp!oyee s occupational exposure profile to asbestos, specific work practices and preventive measures prescribed, 1f any. U H.. allh Education/Appraisal of Health Hazards i ~ ! [ v.:ry employer should ensure that all workers(employees) on employment and at periodic interY::lls should get education and training in regard to sources of asbestos dust exposure, !"'1tcntial health effects, risk associated with asbestos dust exposure and smoking and, mt:thods of prevention. -: ' The employer must apprise the employees of adverse synergistic effect of smoking cigarettes, bccdies, cigars and occupational exposure to asbestos. It is suggested that this information h: n1:1dc available to all workers exposed to any level of airborne asbestos particulates. }--' \1cdic:tl Panel~ {)~,_ of the points amongst the terms of reference assigned to this Study Team was to r :-::,mmcnJ on the formation of medical panels and their composition, for providing final ,! ..sn(,1s ;:1 cases of dispute or doubt. The Study Tean~ considered that: . '. ~ t ' 1r1 \ icw of the complexity surrounding the diagnosis of Asbestosis and other asbestosrelate<l Jist.:as<.:s, separate medical panels should be created for adjudicating on all c.ises of such diseases and entitlements for compensation; .:.~: p.tncls should be created in different regions, keeping in view the geographical density of .t~bestos based industries. This will be conducive to early disposal of disputed cases; :-.; ; ~uch panels could b~ created unde)r suitabl,e enabling prov1s1ons of the Factories or the Workmens' Compensatio:-: Acts and should function in addition to the Pncumoconiosis Bo:trchiPands under the Indian Mines & the ESI Acts; _:;..;A such panels should also function as referal bodies in cases of asbestos related diseases for \wrkcrs not covered by the Indian Mines Act or the ESI Act; 34.5 34.6 34.7 34.8 20 preferably, such panels should comprise of the senior-most chest physician or a ital, the professor of diagnostic "' senior professor of chest sician diseases who has of a teaching hosp been especially trained in iLduscrial dust diseases radiology or a phy stos dust or an experienced occupatio_nal health preferably those related to asbe physician, if available. Otherwise, a panel would have two chest physicians and one radiologist as members, with the senior chest physician as the presiding officer; in view of dearth of medical expertise in diagnosing Asbestosis and asbestos-rdate<l onstituted panels a::-e encouraged to dviisseitasthese, rietciosgdneissierdabilnesttihtuattiothnes manedmpbaenrselosfatbhreocad to obtain specialized training and experience in this field; sfiuncahl panandenlsomt jauystriecfiaebr lteo oeracrehferoatbhleer toinpcaanseelss oof fsedeomuibntglybuitncthreeaisrindgeciimsiopnosrtawnocuel;d be opinions of national or foreign experts, if obtained in a particular case or cases, should be made available to the appropriate panel for its consideration. ,.._ .. 21 FINAL REPORT OF THE STUDY TEAM 'H' FORML:D UNDER THE AEGIS OF THE COMMITTEE "TO STUDY THE HEALTH HAZARDS IN ASBESTOS INDUSTRY" CONSTITUTED BY THE DGTD PANEL ON ASBESTOS PRODUCTS INDUSTRY i'lH:FACE Jn pmuanc1.: of the decision taken by the DGTD Panel on /.~bestos Products Industry to con-.1,1u1c a Committee to "study the health hazards in asbestos industry", a stuciy team designated as ~w.Jy Tc:im 'B' under the aegis of this Committee was constituted. The study Team 'B' was assigned :!-:: t.:isk of examining the adequacy or otherwise of the existing legislative provisions for protecting ( ;::.:llp;uionally exposed workers from the risk of asbestos induced maladies. Tb: Chairmanship of the Study Team 'B' was 'entrusted to me by the Committee and I had the p:11lc3c of heading the team of 10 emment expert members who were specially drnwn from the (1 1n crnmcnt regulatory agencies responsible for the Factories, Mines Safety, Environment, the Industry .:.:~d the Asbestos Information Centre in order to provide a broad spectrum of experience concerning c::c n;bjcct. The expertise of the members has indeed been of immense value in the study and critical ;;. ~l!ll)')i; of this complex subject. 1 .,..;;.h tu place on record tl~e ready and whole-hearted co-operation that the Team received at ,;,jJ rJ;;c;:~ it v1,,itcd, including asbestos mines an(: the factories. The visits afforded the opportunity for ,~ fn:.:: ,_,diangc of ideas with the producers of ;,sbestos fibre and asbestos-based products both in the t:io:ic .u well as the small scale sectors. I, on behalf of my Team members and myself would like to t:'J rrc1'\ my grateful rhanks to the management of the mines and various industries and their personnei ..., fh' ~odpcd us to compile the factual data and relevant inform::i.tion on the status of protective --:::t'1t:..rc' that had been adopted by them. ! 11"0ul<l also like to gratefully acknowledge the active advice and guidance that I received from r:,,. l<".!lm members who showed great commitment and dedication to the task and did not hesitate to rc .1j1ly .i;i\c their valued time for the series of meetings and study visits to distant and far flung places l:'\.:.C;d,bpah in the Andhra Pradesh, Udaipur region in Rajasthan, Hyderabad and Bombay. ! ...-~;!d fin:llly like to thank Mr. D.K. Biswas for providing me this opportunity to lead this C':npctcnt team of experts in their respective fields connected with the task assigned to me, as the H ;iJcrab;iJ, M~> 21, 198:\ Sd. (Dr. G.G. DAVAY) Chairman of Study Team 'B' 22 FINAL OF REPORT OF THE STUDY TEAM 'B' FORMED UNDER THE AEGIS THE COMMITTEE '~TO STUDY THE HEALTH:HAZARDS IN ASBESTOS INDUSTRY'' CONSTITUTEDBY THE DGTD PANEL ON ASBESTOS PRODUCTS INDUSTRY Terms Clf Reference l. The terms of reference assigned to the Study Team 'B' was to examine the adequacy or otherwise of the existing legislative provisions for protecting occupationally exposed workers from the risk of asbestos induced maladies. Later on, the Study Team 'B' was also assigned the task to study in depth all aspects of Workmen's Compensation Act, ESI Act and insurance cover for the asbestos workers. 2. U~der the first term of reference, the Team was required to study the Factories Act, Model Rules and Schedule XIV on asbestos framed under the Factories Act, other guidelines issued by the Government of India, the Mines Act and the Draft National Regulations formulated ty the Asbestos Information Centre (AIC). 3. Under the second term of reference, the Team was asked to include in its study the agency for deciding the claims of compensation, the level of compensation and the policy of the nationalised insurance companies regarding insurance cover for disablement arising from exposure to asbestos dust. Study Team and its Action Plan 4. The Study Team 'B', comprised as under, was constituted by the Committee "To study Healtl1 Hazards in Asbestos Industry" during its First Meeting held on 25th February, 1984 in the Department of Environment, Bikaner House, New Delhi: (a) Dr. G.G. Davay Chairman (b) Dr. V.P. Gupta Member (c) Dr. G.K. Pandey Member (d) Mr. G.S. lchhpurani, Member (e) Mr. B.K. Sharan Mi.:mbcr (f) Mr. N. Venkataraman (g) Mr. J.B. Amin th) Mr. V. Pattabhi (i) Brig. D.B. Kapoor, Member iv1em ber .tviember Member ... I :.:1 ~ 1I : (j) Dr. P.K. Sishodiya Member 5. The first Meeting of the Study Tea1m 'B' was held on 1st September, 1984 in the Factory Insp~cto rate Office at Bombay. During this weeting, it was decided that indepth irnowledge of the working conditions in various types of asbestos based industries, asbestos mines and docks would be essential to enable the Team to make effective and practical recommendations. It was thus decided that tht.: Study Team should visit various asbestos factories/mines and the docks. Consequently, visits were organised to the mines at Cuddapah and in the Udaipur region and asbestos milling plants at pithcads and asbestos product manufacturing units at Hyderabad, Bombay and Udaipur region. The existing provisions under th:: Factories Act, Schedule XIV on asbestos and Model Rule 123,\ were revicw~d. Simultaneously, the provisions of the asbestos regulations of the Western Countries like Ocupational Safety and Health Administration (OSHA) Standards, U.S.A., Asbestos Regulations, U.K. and tll\.: Draft National Regulations, formulated by the AIC and the ILO Code of Practice were slucl.ed. The Study Team also took up for review the modified provisions of the Workmen's Compensation Act, ESl Act and the applicability of general insurance cover so far as it relates to asbestos-related occupa- :-. tional diseases. The knowledge and experience gained by the Team from these reviews/visits were fully utilised in making its observations and drawing up its recommendations. 23 The report on the visits of the Study Team to the asbestos mines and pithead milli11g plants is given at Appendices 'A' & 'Al.' Teams' report on its visits to the asbestos products manufacturing units is given at Appendix 'B'. Obsi::nation<; 1. General r otherwise he risk of jy in depth is workers. lode! Rules 1e Govern1s Informa- agency for nationalised bestos dust. tudy Health Department irman 1ber' 1ber 1ber ibcr 'l!t.. ,1ber nber nber nbcr ory lnsp;;ctothc working I be essential idcd that the '/, visits were :s at pitheads The existing ' :re review ~d. ~ Ocupational; U.K. and the. were stud:ed.;' ! )ensation Act, i :lated occupa sits were fully ; 7.1 The visit to v1nious asbestos factories, mines and pithead processing units revealed that the workers in these units are subjected to exposures which vary from levels much below the accepted levels at one extreme, to highly objectionable dust levels at the other. Under these conditions, it would be reasonable to assume that the anticipated health risks will be in relation to the variations in the exposure levels. The widely differing exposure levels observed at the various sites visited is attributable to two important reasons. The first point of importance is the proces~ employed or the type of plant and equipment used by the units. In most cases, where the dust levels were visually observed to be above the accepted levels, the process employed wa' s part mecha111.sed and part manual and the plant and equipment did not possess and/or provide even the simplest of dust control meth- ods. There are certain processes inherently dust prone, such as, whipping up of asbestos containing ore or asbestos fibre in the open in dry state by means of mechanical equip- ment. There are other processes where there will be least release of dust even with minimum precautions. So, it is essential that each of the processes is studied to determine whether the operations can be performed with better process techniques or better equipment and whether appropriate dust control measures are likely to bring down the dust levels to accep- rable levels. Knowledge of State-of art in the process will help to make proper decision. If such a possibility does not exist, the process should be abandoned or considered hazar- dous, requiring the use of approved personal protective equipment until desired modificat ions to the processing plant are implemented. In no case should personal protective equipment be considered a permanent substitute to effective preventive .engineering control methods. It can at best be a contingency measure, to reduce personal exposures. The second point of importance is the level of implementation of the i>tandards. There are units where the Team noticed adherence to these end and a total neglect of the same at the other end. One reason ignorance and lack of knowledge about the hazards and implications in 11SC Of asbestos. in-house hygiemc standards at one for the latter is the the handling and L~islstlYe Regulations for A<;bestos 8i l f'actories Act & Rules ~" L J The existing definition of the word "asbestos" in the revised Schedule XIV was exammed and the Committe{! found it adequate, as mentioned below : .. Asbestos" means any fibrous silicate mineral and any admixture containing actinoiite, amosie, anthophylite, chrysotile, crocidolite, tremolite or any mixture thereof, whether crude, crushed or opened." s, 1.2 The pro\'isions under "Application of Rules" and "Method of Monitoring" given in Schedule XIV are considered adequate. However, some minor changes are required. b 1.3 The committee examined the existing Model Rule 123A for the permissible exposure limit values for asbestos. The Committee felt that there should be no distinction for different types of asbestos fibre and that the standard permissible exposure limit value of 2 fibre/cc is considered adequate. This provision has now been included in the Rcvi~ed Model Ruic 123A. b. 1 ~ S..:hedule XIV on asbestos and the Model Rule 123A specifying the permissible limit of exposure have not yet been adopted by many of the States. s i.:S The method of sampling and estimation ,,f the asbestos fibre dust in workplace environment is not provided in the Schedule. Also, ere is no national standard method for workplace environmental sampling and asbestos d~. lev::l measurements. II 24 i ended in the Model Rules should be further explained to I 8.1.6 An exposure level of TWA recomm ategy. lSI should be requested to incorporate these details in the include sampling str ment of airborne fibrous dusts. Standards for miedaesrus rtehat the measurement of asbestos dust levels is thae caosmsipslteanxcetecohfniwquelel 8.1.7 The Team cons liable to wide variations unless enough expertise is developed with established asbestos dust counting laboratories. ractical aspects of counting I 8.1.8 There should be a procedure and programme to stantidoanrsd. ise the p ' of the fibrous dust to reduce inter-Ia boratory varia Il 8.1.9 f the view that no sampling and analytic technique other than the Membrane tc countings by The Team is o ) be used as no accepted formula exists to coreln economical method univer- (MFT d ~ FdiilftfeerreTnet cmhnetihqoudes and MFT is by far the most practical an sally accepted for this purpose. 2f/cc as the TWA for all types of asbestos dti,t. 8 .1.10 The revised Schedule XIV now specifies f the trend in the advanced countries to further lower the peronomic The study Team is aware o wever, after car~ful consideration of the present te::\ 110-cc at several countries, h mfeiasssiibbilleityliimnitI.nd.iaHtoo implement the standard and bearing infemelisndthat t the present recom e.g. Japan, still consider 2f/cc as adequate, the Study Team ractical provision at this poirt of time. eded permissible level of 2f/cc is the p lOf/cc on a 10 minute sampling penoc m 8.1.11 It is also considered that Short Time Ceiling Value of may be accepted. gested by this Study Team is included as Appendix'C.' lt is. ol '* 8.I.J2 Method of sampling sug d that the ISI should soon bring out a standard for the measurement however, suggeste fibrous dusts which should then be uniformly adopted. 8.2 Small Scale Industry in operation it was observed that they ne1the 8.2. J During the visits to small scale units already rces nor the technical have the adequate financial resou ke suitable control measures. competenc~ to come to grips w;t the problem and to ta lished and are in operation, the Te:lm recommends th: 8.2.2 As these units are already estab isted to implement the regulatiO,iS much the same way an SSl unit d tcchn1c:: theseeduntoitsesbteabalsissh manufacture, by way of several incentives both financial an se of asbestos ~nd other su' help We are afraid that the :iiternative will be prohibition of the u The areas where these units require as,: .; toxic substances by the Small Scale Industry. t.tfiaer tance are as follows : idy should be given for the purchase of equipment needed for t: Financial : dSuusbt's, personal sampling etc. Capital assets under 1.his category sho11l 1l no1 r SmJl! Sc: control of counted for the capital investment clause which determines classification fo '' Sector. D.l.C. or other concerned agency s!1oc1lcl '.: Engineering; A technical cell in for the suppression/control of asbestos dust and to I:: directed to pool the technology Industry to select and install appropriate equipment. the Small Scale Nfg_a~urements & Hea!rh Control: The Small Scale Industry should be encouraged to p ealth survc 1 their resoUJ-ees and establish a centralised dust counting cdenptreer,soans. also a h I ance centre the supervision of a competent qualifie b~ made aware of the need for stnc! : Employe::s in this industry shoulrl the health hal:lrds that might ar;s,~ du: Education plementation of the asbestos regulations and occupational exposur.: to asbestos. :xplaincd to ~ ~ ~ 3 ~tails;.,.. the x technique nee of we!l 5 of counting e Membrane countings by ~thod univer- asbestos dust.. 1wer the per- . hno-economie . ml countries, resent recom- 1mpling period idix'C.' lt is, cnsurcme1lt of......... 25 :-Oiin<'s Act; Regulation1; & Rules Thereunder. 8.3. J During visit to the underground mines, fibrous deposits were noticed on the roof, walls and floor \vhich were dry and were not kept wet in the travelling and haulage roadways. Relevant regulations of MMR 1961 do not provide for enviro1u11ental survey of open cast mines and underground mines less than 50 metre depth. These also do not contain appropriate methodology for counting the asbestos fibres present in the uuderground working environment. It is necessary to provide for such surveys and suitably amend the MMR 1961. S.3.3 ~t3A lL3.S The open cast mines in Udaipur were mmmg the ore deposits manually without wetting. It i; necessary to monitor these workplaces,, to approve the present method of working. During the visit to the mines, the Team also observed the milling process being carried out in the nationalized as well as in the joint and the private sectors. It \\3S observed that the processing is carried out using small machines without total/partial ~u~t control measures, resulting in unsatisfactory dust level exposures to the workers. ~-.:t.6 The scale of operation of these mines will not allow the installation of the required plant for achieving acceptable dust exposure levels as the cost of such plants are reported to be approximately one crore of rupees. ~J. 7 The Tc:nm suggests that the milling operation be pooled to millwg plant with complete dust control systems & provision ;.\;i~te &. tailings. enable installation of modern for safe disposal of asbestos ('or.nplhrncc of Rcculations. mt they neither e to grips with :commends that an SSI unit is and technical. and other such ts require assis-, needed for tht >ry shout d not b n for Small Seal ~ency should t 10 dust and to he! ncouraged to po a health surveil need for strict ir might arise due'. 9.1 It i~ observed that State regulatory agencies entrusted with the task of implementing the ..:ontrnls on asbestos and other toxic substances are presently not adequately equipped with proper equipment and other resources, including trained man-power. These facilities are cs-;cntial to ensure adequate compliance to protect the health and safety of the workers. 9..2 1 i:c mdustr; ~bou!J periodically monitor dust levels to ensure the effectiveness of the 1, Ct'l)!!1ncering conlrnh. <jl :i '!!';t" Tc.im f,;''(iHd the record of monitoring from several ind us tries. Whichever of the , J_\I~ un;:~ that h:is not yet implemented the monitoring scheme is advised to do so 'Iii ;:::nut :my further loss of lime. The lc:un rcquc~t:> the Government to be liberal in allowing importation of the latest equipn"'cn! r~quircd for the purpose of monitoring dust levels and medical surveillance of emplo- Some ,,f the small scale manufacturing units and pithead processing units had emyloyed children and a<loksccnts who were being exposed to heavy dust exposures. The Team con1:ikn that this practice be prohibited. r.kcocing of ~ew ~tanufacturing Unit~. ,.1;., Durrns the vi~it lO v.1rious factories the Team observed that several equipment and plant no~ being us~d are not by design meant to process asbestos fibres/products but have been ..'ldoptcd for the purpose in an adhoc manner by the mana~ement. It is felt that equipment I llnJ pl.int used for this purpose are manufactured scientifically, taking into consideration the need 10 l:ecp thc air-borne asbestos dust within the permitted exposure levels, whether it is v.ithin thc factory or in the stacks, when let out into atmosphere. While the Government now rC(iuircs specific environmental pollution control measures before any new licence is tr .rntcJ such specific provision to control workplace exposures is not existing. Notwithstanding , 26 s existing in the Factories Act and Rules, it is recommended that the approing I-! the provision satisfy itself that adequate provisions are made before licens nature to avoid pfurirathteerauutnhiotsr.ityTshheouplrdovisions should be specific and not general in subjective decision making and to ensure uniformity. 10.2 The Team has also been informed of certain manual operations where no power is used and agency. It is the considered hence, may not come under the purview of any regulatory operations and places be brought under Central/State orpeginuiloantooryf tahgiesnTcyeabmy tthheatuseallofseuncahbling provisions under the main Act. I-! 11. Packaging & Handling of Asbestos Fibre. 11.1 The Team haasndtalekdenatnoptlaectehsawt cheerrteainthoe pefancattoioryns raurleescaarreriendot oapupt liocuatbslied,eptrhoemfiancetonrty awmhoenrge both-imported and indigenous. asbestos is h them being the handling of raw asbestos, 11.2 The Team observed that fibre produced indigenously sometimes is packed in ordinary jute should be packed securely bags. Such a practice should be prohibitedh.ad wAlilthasabnesintossidfeibpreo!ycthcne film lining. Woven in impermeable bags. Such a bag can be plastic bag with inside lining is preferred. Use of hooks should be strictly avoided and such an instruction should be printed on the bag. 11.3 When imported, the asbestos fibre should be unitised. Handling of individual bags should docks sh0L1ld be standar- ar as it is practicable. Handling procedures at the handling equipment to urJoacl and carry the be avoided as f dised to encourage the use of mechanical unit loads. 11.4 lSl should be requested to formulate a Code of Practice for the guidance of the asbestos users, both in factory and non-factory operations. I.! \ ) I~ "'ul, : : H J.h;. .. ( 12. Medical Surveillance. ' The methodology to adopt medical surveillance is a subject for another study team whose lindings would need to be integrated with this Report. 13. General Environment. The Team has not studied the emission of asbestos dust from the asbestos product m:muThis aspect ,, '. 13.1 facturing factories or asbestos processing units into the general environmcn t. However, the Tc:lm considers that the wStaastebePyoollnudtitohne Cpounrvtrieowl Boofairtdsstesrhmous lodfloreofkerienntcoet.he feasibility of bringing out standards for emission of asbestos dust into the ambient air. 13.2 The Team observed that the solid waste tailings from the raw asbestos processing units w:is 1s haz:udous. The Tcn , 1 being stored in the open and then, disposed off to the disposal of public, which solid waste tailing~ 1 be drawn by th~ cDoenpsaidretmrsetnhtaot faECnovdireoonfmPernatc/PtiocleluftoironthCe ontrol Board/ISI in accorcnncc with intcrnation:tl practices. - 14. Compensation. 14. l At present, the Workmens' Compensation Act, 1923, covers asbestosis: lung cJ11cc:r and exist some unc.:ruw1 mesochelioma when they are caused by asbestos. However, there still ties in the interpretation of these provisions. 14 2 Criteria for the diagnosis of the above mentioned asbestos-related disc<ises need tc b: specified. 27 d that the appro- .., before~ licensing :iature :1 a void Jwer is used and s the considered lcr Central/State l 4.3 HA 111 case of Jung cancer and mesothelioma, it is known that several other factors could cause the same diseases and hence, there should be criteria for identifying them as related to asbestos exposure; for example, in the U.K. when lung cancer is present alongwirh asbestosis or bilateral pleural thickening asbestos is deemed to be its cause for the purpose of the compensation. There is also a need to designate an agency with specialized training to decide the eligibility of claims for compensation from the m~dical angle. :he factory where rominent among in ordinary jute : packed securely m lining. Woven ;tly avoided ~rnd H.5 The ESI Act docs not make provision for compensation after the cmployec-ESIC relation~hip has ceased to exist. The ESI Act should be ammended such that the ESIC is made liable to pay compensation, even after cessation of ernpioyee-ESIC relationship, for diseases covered under Schedule III, Part C of the Workmen's Compensation Act. In addition, ESIC should be required to provide life long medical facilities in such cases. ;.:.6 Employees not covered under either of the above Acts are not eligible for any compensation. 1 he employers should be asked to take insurance with National Insurance Companies for all their employees not covered by the ESI Act. Such Schemes should cover the life of the employee and not the period of his employment. JS. Subtitution. iual bags should ould be standar 1ad and carry the Th Srndy Team noted that DGTD Panel on Asbestos Products Industry is already seized with :he <u;>cct of substitution of asbestos fibre by alternative fibrous materials based on technical consi-. J~n1!i(inS provided they arc less hazardous to health and offer equivalent techno-economic advan~t<-i In views of this, the matter was not pursued. :c of the asbestos 1 whose findings !~ R.tci~mmcndations .. -\ !;. ;. rc;ults of the visits, deliberations and the observations made in the preceding paragraphs, rb: StuJy Team offers the following recommendations : 11_, I Current prescribed level of 2f/cc as specified in Model Rule 123A is considered adequate at the present time. MFT should be used for the measurement of the air-borne asbestos fibre llUSl (lSO draft is available). :>s product manu:nt. This aspect considers that the out standards for cessrng units was dous. The Team be drawn by the 1itb international l. Iung cancer and ! some uncertain-' seases need to be lf>-,; Framing of Rules according to the Schedule XIV and Model Rule 123A by tlie concerned ~t:1tc~ is an urgent requirement. ;6 4 i 6 :, i'4 6 1:1_7 Effective steps to implement the above Rules must be taken by providing all facilities to the state regulatory agencies. These include dust monitoring equipment and specilised trained man-power in order to produce accurate and re-producible results. Measurement of fibre dust levels is a complex subject and efforts should be made to obtain uniformity within industry and regulatory agencies. Personal protective equipment should not be considered a permanent solution rn place of preventive engineering control measures. At best, this should be a contingency measure. Every process and equipment related to the milling of asbestos ore and processing of asbestos iibr1.: should be studied for its potential to create air-borne dust. In case any process/ equipment releases dust that cannot be controlled to the desired limits by engmecrmg control methods, such process/equipment should be prohibited. [quipmcnt used in the processing of asbestos should carry a certificate from the manufacturer that during normal usage as recommended, the equipment will not release fibre dust levels high1.:r than the prescribed limit. ~fan:igcment and control of asbestos dust in the small scale sector of the industry need to be 1~:ck led on priority basis. Major rccomrncndatioas in this regard are: 28 Financial : Subsidy should be given for the purchase of equipment needed for thecontrol of dust, personal sampling etc. Capital assets under this category should not be counted for the capital investment clause which determines classification for small scale sector. Engineering : A technical cell in D.I.C or other concerned agency should be directed to pool the technology for the suppression/control of asbestos dust and to help the small scale industry to select and instal appropriate equipment. Measurements and Health Control : The small scale industry should be encouragec\ to pool their resources and establish a centralised dust counting centre, as also a health surveillance centre under the supervision of a competent qualified person. Education : Employees in this industry should be made aware of the asbestos regulations and the health hazards that might arise due to occupational exposure to asbestos. 16.8 For licensing/registration of new units, specific requirements of dust control to be met by them should be listed out by the competent authority. Licence should be issued by the competent authority only after satisfying itself that such requirements have already been included in the project. All operations and places where asbestos fibre is used shou!d b~ brought under th~ purview of the Factories Act and Rules, irrespective of the size of the workforce or usage of electric power. 16.9 The regulation and rules made under the Mines Act 1952 need to be moJified to bting them upto the International Standards for the control of asbestos fibre dust durit1g mining, handling and milling of the ore. Where applicable, the rules under the Mines Act should be modified so as to include tlw relevant provisions of Schedule XIV and Model Rule 123 A made under the Facrom,; asbesto~ Act so far as they relate to asbestos fibre dust control. Asbestosis ; lung cancer and mesothelioma when they are caused by ;,hould \ ?.e notified as occupational diseases under th'! Mines Act. ---" , \ Specialised trained manpower and equipment arc to be provided to effectively monitor the environmental exposures in mines and medical surveillance system of the mme workers. 16.10 State Pollution Control Boards should make emission standards for th~ co1~trol of ~i:,b.c,.tos fibre dust in the general environment. 16.11 16.12 Packing of raw asbestos fibre should be in impermeable bags and should be handled :t-; unitised loads as far as it is practicable. Empty bags should be dispos:cl off a<> per i.1tcrnational practice and should not be given to the pu bl!c. ISI may be rc,1 uestcd to brrng 011t the Code of Practice for packing, handling, transportation and use of asbestos fibr.~. The employees covered under the ESI Act should be eligible for compensation aft ~r cessation of ESI cover.age, as is the case in Workmen's Compens1tion Act. Clear criteria for the diagnosis of asbestos related diseases should be specified and should be uniformly followed. In the case of lung cancer which could also be caused by various other reasons it should be made c;ompensnble only when either asbestosis or bilnternl pleural thickcnin~ i, concurrently present. dcd for the .i1!1 ,. ould '.10t be in for 1all be directed to help the 1couragcd to llso a health s regulations cstos. ol to be met be is~ue d by have already ;ht under the workforce or ifie<l to bring c dust during o include the the Factories ' ' 29 There is need to designate an agency that possesses spccinlised training, expertise, competence and facilities to decide the cases entitled to compensation arising out Of as bcstos-related diseases. Employers should be required to cover 'their employees under general insurance m case they are not covered under the ESI Act. lt iJ Government should be liberal in allowing the import of equipment required for the use in dust monitoring and medical surveillance. It lot ISi may be requested to expedite formulation of: Standard for the measurement of airborne fibrous dust. Code of Practice for the packing, handling, transportation, factory, mine and other places. and use of asbestos in the ;~ ! ~ Code of practice for the use of asbestos containing products. Code of practice for diposal of asbestos waste materials, including tailings and empty bags. Following amendments to Schedule XIV on asbestos be carried out : The words "following operations shall be enclosed and provided with'', be added before 1he words, "exhaust draught fitted with mechanical means" in sub-para (1) under para 4. The Clause 'd' under sub-para (1) of Para 4, be deleted. ;bcstos sl1ould tivcly monitor m of the mine : , i' rol or a~bestos ' JC hancl!ed as ,ff as per inter- , d to bri'.1g out, fibre. p~nsat1on after, , 1 :t. ficd and should easons it should J thickening i~ 30 APPENDIX-' A' VISIT TO ASBESTOS MINES IN CUDDAPAH DISTRICT OF ANDHRA PRADESH 1. The names of the team members who visited the following mines and processing plant~ to study the health hazards in asbestos mines are given in Annexure I : (a) Joint Sector Mine. (b) State-undertaking Mine. (c) Smafl Private Mine. 2. The Team reached .. Puli~endla. at. about 10.00 A.M. on 15th January 19G8.5S.. Tlchhehpguenraenrai,l mining method and operations were explained to the Team by Mr. outhern Zone. Mr'. P. Choudhary, Managing Deputy -OirectoT-Geheral of Mines Safety, S Mr. K.V.S. Ram, General Manager, A.A.C. Ltd. explained the Director, A.P.M.C. and general geology and -method of working of their mines.. 3. General mining _operations involve drilling, blasting, sorting, )oading of the ore into the processed at surface mill. details tubs and hauli~'g to _the s'urface; The run of mine ore is rysotile asbestos fibre is mined at Pulivendla. of which ar~ given subsequently: Only Ch 4. There are about 10 underground asbestos mines situated in Pulivendla ar~a. elidan<lla The total strike village. The ore gth of the deposit is about 14 Kms from Brahmanapalli to V to metamorphism of dolomite rock. Asbestos occurs len body outcrops. Asbestos occurs due deposit in serpentine vein. The thickness of the asbestos veins vary from few as very thin m.m. to 250 m.m. The average thickness is about 10 to 30 m.m. The thickness of the serpentine vein is about 1 metre. The general sate of dip is 1:4.5. The asbestos bearing sent depth of the deepest working mint: rock was proved upto a depth of about 200m. The pre tres. General geology of the mine is same for all the mines. The biggest mm~ is about 125 me tate undertaking. Four mmcs arc worked by Andhra bAeslboensgtsos toCtohrepoAr.aPti.oMn.CL. twd.h, icwhi1isicha Sis joint sector (A.P.M.C. and a Public Sector). Other mines belong to private m!ne owners. 5. Method of Working. The method of working is almost the same m al the mines. lnc\1nc~ are driven from the outcrop and serpentine vein is developed in a bord and pillar pattern. width of the gallern:s var ics Height of the drives varies from 1.5 metres of the to 2 metres and the pillars varies from 5.5 m x 6.5 rn to 15 m x 15 m from 2.5 to 3.0 metres. The size mineral blocks are stopped out by overhand/or breast stopping by cut and till, (solid). The two rounds. The lower half, c0ntaining the 1~11ncral, mis ebtlhaosdte. d iTnhseecdornidvesrouarned. blaTshteedminineral obtatned from the undergrc)un<l is brought to the surface by direct haulages. ') Joint Sector Mine-Date of visit 15.01.85. .,i 6. The Gcryeral Manager explained the method or.f wGo.rSk.ingI.chhTphueraandid. itiAonfatelr sitnufd0yr:innagutohne ' required by the m~mbers was furnished by M ent down through the manway to 1st level and travelled upto 2nd dip and plans, the team w went down to 4th level through 2nd dip, and entered the return airway through the' ~ur crossing and reached the 8th level through companion dip. vel After studymg and inspected the general lay0u1 the old stopped and the method of working, the team went upto 4th en worked by le the previous owners. The team returned , out ftrea (Panel No. 1 ) which had be to the surface through th e same route. During the visit, it was oh:;e~vcd that Larmful clu:it ' was deposited on 1 the sides of the travelling roadway. "' f'. 'END A~ ing plants to The general Ichhpurani, ry, Managing explained the e ore into the e mill. details Jlivendla. he total strike illage. The ore sbestos occurs {ary from few 1ickness of the ;bestos bearing . working rnme ,e biggest mine ked by Andlua. : Sectod. Other I iines. Inclines d pillar pattern. galleries varies to 15 m x 15 m g by cut and !ill rng the mineral, " brought to the nal information fter studying the .1pto 2nd dip and th rough the air h-:: general layout the old stopped he team returned hat harmful dust 31 Tilt: \\Orking ~nvironmcnt, ventilation system afid gcnel'al surroundings in actual working :iil<l operations were observed by the Team members. :-. f>roreViing of Mineral . . Then, the Team members visited the processing plant. The run of mine is loaded manually into the tub and hauled out to the surface. The run of mine 1s subjcctcd to manual sorting of the asbestos bearing rocks (ABR). The ABR is then handcombcd for chipping off the asbestos bearing portion in smaller pieces ranging on an average 2.5 Cm. ( l") pieces. This is collected and is known as asbestos concentrate. From the ABR, the serpentine rocks arc 'removed as waste. The asbestos concentrate is fed manually into the hopper of the hammer mill. In the hammer mill, the asbestos and other minerals arc ,cparatcd which are fed to the double deck screen which has sieves of IO and 40 mesh. The '":recning gives three fractions : 1:1 ~ Oversize. !bl Middling. \cl Tailing. Luling is the waste which generally does not contain appreciable quantity of asbestos. The (i\r!>izc is recycled in the hammer mill and the middling fibre is sucked up by a cyclone and .;,1lkctcd. Whatever solid comes from the separation of fibre in the hammer mill is again fr,l in!O the hauler. The fibre in middling is again subjected to double deck screening ?!.;l ving mesh size of 16 to 40. Particles which are less than this mesh size are a waste, "'hich is taken out for dumping. The fibre from the screen is again sucked up by the cyclone ~i:-r~1rator and the fibre is collected. :\II the operations which involve feeding of discharged material to the other processing r:i:ichincs are conducted manually. It was observed that the air from the cyclone collector ,., lhrown out into the external atmosphere without passing the same through bag filteration \~"'Item. The fibre from the cyclone is collected and removed to blending area where differ:nt batches are mixed togethe1. Then, the same is packed in HOPE bag and weighed. The r,;i.:l.ing is done in 25 and 50 kg. bags. The E~1gi~tre_~-~.!)~.~~lJed with_~~~ hazardous_p_i:9_i:>_e- ----- n:c;; or asbestos and its source. ;o,ucc t ndatakings Mine-Date of Visit 16.01 85. -.; n.o Managing Director and the Manager were present during the VlSit. The M~1naging Dirc..:tor explained the method of working. Then the Team went underground. The uri,Jus operations such as drilling, mucking, transportation, charging and blasting were ..irrangcd so that the Team could study the dust problem in various mining operations. }LI n~.: Team went down by main travelling roadway to 2nd level and through the winz~ ~0. 23A went down to level No. 6 and then reached the level No. 7 through the air crossing. Th~n through No 4 incline and winze 12A, the Team reached level 9 and inspected the f,11lowing faces : Lcvcl 9 East face-drilling operation. 11 dip of 9th level-mucking operation. , "' The cl1.arging and blasting were arranged in level No. 9. First round of blast for 12th dip \~.1~ arranged. Six holes of 1.2 metres were already drilled and kept ready for charging. Thc holes were charged with two cartridges of slurry explosives with ordinary detonators and fuse. After observing the charging operation, the Team returned to the surface. Dust ,;impks were collccted from the airway. 1.:. The T ..:am visited the processing plant. The run of mine is handled the same way 1s in the Joint Sector Mine. The asbestos concentrate is fed into the jaw crusher and sieved for grading. The jaw crusher, crushes large size ABR. Smaller size jaw crushed ABR is fed to the ,fointcgrator. The ABR obtained from the.jaw crusher as.well as the disintegrator are fed 32 edge runner. The lower wheel of , the edge runn!;!r rotates material he workers are required to push the and the vertical two on the rotating wheel material is manually to the wheels are stationary. ner for T obtaining effective pulverising, The pulverised ets. of the edge run and collected i11 troughs and then collected in the bask ln this pushed ted to operation of decosrteipcaartaiotend. . Then, 13. The pulverised asbaersetobslocownntaoiunitnign ma acsoslliescstuinbgjercoom and the solids are process the fibres subjected to another set of edge runners. the solids are sieved in eccentric sieves. The fibre so obtained rser solid particles 14. The collected fibre after decortication ixed are together. In this fashion, the coa The fibre) t in separate batches and m huller which further separates the fibres and solids. is kep d in a cked. aorbctaaignaeidn fpruolmverdiisfeferent sources are mixed and pa Small Private Mine-Date of visit : 16-01-85 the Team came upto ent down through the manway upto the 7th level. Then, ing places : 15. The Team w the 6th level through 2nd rise and inspected the follow 11th dip of 6th level. 10th incline (main dip) drilling. 6th level-Blasting. returned to the surface through the same routt'. After inspecting all operations, the Team run of mine is separated in the usual 16. The Team, then, visit~d the processing plant. The is pulverised in two stone wheel edge runners pulled by ibre from r to obtain ABR. The ABR ass is subjected to decortication which separates the f solids so removed manne a tractor. The pulverised m The fibre is then subjected to sieving operatthieonsw. astTeh. e The fibre obtai:icd the solid rocks. fed to the huller which further separates the fibre and DPE bags. Various operations urn.lertakci; are hes are mixed and packed in H ers to the hazard<> due to asbestos dusL Iinrotmhedpifrfoecreensstinbgatcplant expose the work 17. The Team made the following observations : and making asbestos concentrate (a) The workers tuonadsebretasktoisngfibthree. wTohrekyoafrhearnedq-uciormedbitnogwork in an open area under the sur the summer. are exposed throughout the year, including mill, and hauler operations wer: (b) The first double deck screening operation, hammer the work environrnent (visually). emitting huge quantity of asbestos fibre in air from the cyclone ~ystcr: he collecting of the fibre from the outlet and out-going nvironment. (c) T itting asbestos fibre in the work e as also con tam .were also em (d) The operation of mixing different batches of asbestos fibre manually w A ,,1 nating the work environment. being manually hammered to sort oi; (e) ABR having longer asbestos concentrate were superior grade asbestos : Grade 1 Grade 2 - More than l!" 3/4" to If Grade 3 - ; to 3/4" subjected to manual jigging. The opcmtion of jigging and environment Tinhgesgeavewoefrfe absebiensgtos fibre in the work iwmm; cul two g wheel "'- ianua] in this Then, ' i obtained particles fhe fibres ame upto <.. : e route. l the usual : pulled by : fibre from so removed ire obtained undertaken concel1trate nder the sun rations were yclone system . also contami. d to sort out_ 33 If l Thr O\efitll observation of the Team was that the operation of hammcrmill, huller and cyclone operation were emitting huge quantity of dust exposing the workers and the population in the surrounding areas. rg) Machinery and equipment as well as the auxiliary need to be redesigned so as to prevent emission of asbestos dust in the environment a.nd the.sun:oundmgs. (h 1 Enclosures need to be provided to each of the operations with effective exhaust draught arrangements. The exhausted air from different sources should be passed through enclosed filter bags system and then, only the air which is not containing asbestos dust be let out into the external atmosphere. II) General house-keeping of the asbestos processing plants was very poor as asbestos \\:1s being handled without any regard to health hazards that it posed. Catridge type rc,pirators provided to the workers were non-functional and unsuitable for effecive use!. Workers handling asbestos were completely unaware of health hazards of asbestos. There was no mechanical means to collect the dispersed asbestos fibre dust. Workers' clothes were seen to be highly contaminated with asbestos fibres. No suitable place w.is seen to be provided to store the personar protective equipment. No separate room "1.is provided with dust de-contamination equipment. Workers were keeping their clothes near the workplace. Young persons were seen employed on all operations. ~o cautionary placards relating to injurious effects of asbestos were displayed in the ;t~bestos handling plants. Only part-time medical officer was available for attending to the general complaints of the workers. According to the management, workers employed in the mmes are medically examined only once in five years. No system prevailed to monitor the work environment. ~ and hammer: 34 ANNEXURE-I TO APPENDIX 'A' LIST OF STUDY TEAM 'B' WHO VISITED MINES IN PULIVENDLA, CUDDAPAH DISTRICT, ANDHRA PRADESH I. Dr. GG. Davay, 2. Dr. V.P. Gupta, 3. Mr. G.S. lchhpurani 4. Dr. G.K. Pandey, . 5. Mr. J.B. Amin, 6. Mr. V. Pattabhi 7. Brig. D.B. Kapoor . 8. Dr. P.K. Sisbodidia 9. Mr. M.L. Dabral, Development Officer & Member Secretary, Panel on Asbestos Praducts Industry, Directorate-Genera\ of Technical Development Udyog Bhavan, :New Delhi-110 011 35 X 'A' .A tICT. ~ ,_ i: ' APPENDIX 'Al' \'ISITS TO ASBESTOS MINES AND ASBESTOS PROCESSING UNITS IN RAJASTHAN ,. r Ii.: T earn Members had their first meeting at Uclaiour on 21st February 1985, in the Office of Mr. N. Mishra, Director of Mines Safety, Government of India, Udaipur. The following members and invitees were present : la) Dr. G.G. Davay lb) Mr. G.S. Ichhpurani ic) Dr. G.K. Pandey (d) Mr. J.B. Amin (c) I3Tig. D.B. Kapoor If) Dr. P.K. Sishodiya !g) Mr. N. Mishra (h) Mr. R.C. Chaudhry Chairman Member Member Member Member Member Invitee Invitee Dy. Director of Mines Safety \l) Mr. R.S. Sharma lnvittee Suptd., Geologist Dept. of Mines & Geology Mr. N. Mishra and Mr. R.S. Sharma, informed that there were 45 working mines and 24 closed mines in Udaipur District of Rajasthan. One mine was having underground workings anti the others were opencast. The production of asbestos during the year 1983 was 12,350 M.T. The Deputy Director-General of Mines Safety explained that as per the records of Director:Ile-General of Mines Safety, there were 26 asbestos mines in Ajmer District, of which 18 \ere \\Orkmg mines. All these mines are opencast mines. The mines employ about 250 rcrsons and produce 16,000 MT. of asbestos per annum . ..\ It \\:t~ decided to visit a few opencast mines in Udaipur District on 21.2.1985 and some a~hntos products or processing units in Udaipur and Ajmer Districts on 22.2.1985. \mt to \line~ on 21.2.1985 " J.;1r.:it A,hc~to~ \line (Tal'!_~~I) r ~ c mine \,as being run on the sides of the hillock by opencast method. The size of the quarry was 11\irnatcly 20 metres wide x IU meters high. The sides consist of soft strata and were being . _1rl.~d by pick-axes. The management possesses a lease area of 299 hectares. r r : ;'ro<luction of asbestos ore is about 2,000 tonnes per month. The sides of the quarry were : , : ~:::pt rropcrly benched. The run of the mine ore was being collected in"Tagoras" (M.S. Shallow , :Heh!. The tagoras were carried on head and taken to a stacking place for breaking the ore. The ,- 7 c "'" bL"ing graded into two grades, namely, No. 2 and No. 3. Grade No. 3 is very brittle and in :1~ ;:.c f'()\\ dcry form. The graded run of the mine is carried in the trucks to the processing unit (s). it .,, ,. 0bscrvcd that even cutting the sides of the quarry by pick-axes raised small quantity of 4 ,:,_.~! Ill the air. Similarly, the dust was raised while filling the tagora sand dumping at the ;-:.:i-.:c of gradrng as well as during loading of trucks. The workers were, thus, exposed to the asbestos ..:'.nL for grading the ore, at the mine, the run of the mines was screened manually. This also .::l:..,cd the dust to rise in the atmosphere at the working site. The a~erage earning of a worker ... .a.i '.>!.:llc-J to be Rs. 9.75 per day. 36 6. Ganglr Kiopal Asbestos Mine st method, on the sides of a hillock. The quarry was about The mine was being worked by openca x about 20 metres deep. The sides were cut by axes as stated above. Prnr1cr 30 metres wide out 150 tonnes of asbestos ore is raised from the mine per month. ilar to Kirat Asbc~tos ,Tbehnecmheisnewheraed nsotat rte. drmweodr.kAinbg in 1979. The operations in this mine were sim Mine as described above. sorted into two grades i.e. pipe grade and fibre grade fo1 use in The asbestos 01e was being ore is sent to a processing factory at Udaipur. Asbestos ore 1s plants. The run of the mine supplied as heat insulating material to various plants. steel also 7. Obsenations (a) In none of the mines medical examination of the workers was being earring out. The Director Udaipur District of Mines Safety informed that the medical examination of the workers in ines Safety informed that the same in- had not yet started. Deputy Director General of M the Director of Mines Safety, Ajmer, in respect of the mines in formation was received from acilities exist for such an examination. Ajmer District; in fact, no f (b) No protection was provided for the workers against the hazards of asbestos dust in the mines and no control system had been introduced. any change over dresses for wearing during working (c) Tanhde nwooarrkrearnsgewmeerent nwoats pprroovviiddeedd fowriththe decontamination of their clothes from asbestos fibre dust. Visit To Units Processing Mined Asbesto~ Ore And Asbestos Fibre On 22.2. 1985 These units are located at Beawar and on the road to Beawar from Udaipur. 8. Sindhari Minerals-Gomti Chauraya (a) The mined ore i-; subjected to following unit operations to separate the asbestos from ore: Jaw crushing. Pulverizing. Fine pulverizing. Cyclone for collection of product. Separation of the fibre (Cyclones and Bag Filters)." Sieving of asbestos fibre. Bag filling operation--carried on manually. (b) Observations operations to process asbestos ore into asbestos fibre are highly dus: Several of these prone especially sieving, feeding to pulveriser and filling the bags. No dust collection system and exhaust draught arrangements exist. Thus, entire estos fibre dust. w,irh atmosphere is contaminated with visval dust that includes asb Due to the above, dust is seen in all the places, eg. on the mrrchincry, walls, floors etc. at dust counts wiL be high No dust measurement are carried out but it is obvious th judging from the general dusty atmosphere. PNeorspornoavlispiroonteecxtiisvtes etoqukiepempetnhte wwaosrnkoert's avwaoilrakbilneg. clothes and street clothes scrara tc:ly No Medical examination scheme is existing/provided. !" !- Very young persons are emrl~~,1 =n the plants . . 1, 1 ' This unit is not reported to be c..~vered !inder the Factories Act. 37 y wa~bout .bove. roper per month. irat Asbestos use in steel S ore is also The f0lkming unit operations arc earned out to separate the asbestos fibres from the asbestos ore: la) Jaw crushing. ; bl Pulvaising. 1.;: J Cyclone collection. ,,!J S1~vinr the fibres. \;) ,\JI tilling and transportation operations are done manually using tagoras and powaras. n.c ob,crvations on the working conditions in this unit are similar to those of the Sindhari \L::ia .ih, Gomti Chauraya, mentioned in 8 (a) above. The Director 1ipur District the same in the mines in I~ -~~to,c\mcnt Sanitary_Ware. .n.n factory also manufactures sanitary wares, bends, joints and other accessories. f,JU.:v. mg operations arc carried out : Li; ~.hxrng asbestos fibre and cement and then, water. ., t in the mines ' itt Moulding of the product. 1<::.t 0I)rng. iring working a,sbcstos fibre ' ;,:i hm,hing. i,. t Curuig. " J& 01 iht'\cc operations (a) and (d) are dust prone and, again, no precautions are T~:.c- !.Htory employs 9 men and 5 women. '"**' '\tional Tradinj! Corporation, Deogarh. Kamli Ghat. existing. from ore: H ~trf!.'.')' ~bout 7 men and 5 women. The factory processes about IO tonnes of asbestos every <!!J.f o,ffcrcnt grades of asbestos dust and fibre are pulverised. The pulverised material is collected u ..! 0 '-"md and dumped or filled in the bags manually by tagoras and powaras. Different grades N ;'H~rc<l, which depend on ~he fibre content. Okrtotloa. ~ :..X.i.l Holilation or exhaust draught management is provided. -:lf.,:;.t..:- ~..,r k' the same as in other factories, described earlier. The working conditions arc.:. t! ~u "tincral Trading Co., Beawar. .re highly dust. ; ~ .; t:);;h.1) co arc engaged in manufacturing activities. \~ ,.., ~..: .nb.:~tos is pulverised and stored in chambers. After chamber rti:.::""'.: nrnually. The material is then graded and packed manually . is full, the material is .;, entire work IS t. ls, floors etc. ts wil. be high, 'k' lh entire area was contaminated with asbestos dust . ,~. Tb: 0rcrarions like pulverising, :1 ..11', 1n this factory. bagging, transportation etc. are more hazardous opcra- (..i 1 here i~ no dust control and dust collrction systems. \Jl n~c unit is registered under the Factories Act. l j lir.tmpI A.'be'ifO'i Pipes, Beawar. 1cs separately. i: , 11,plo)ccs seven persons and manufactures asbestos cement pipes and bends. Asbestos and .;;r:::nt .ire mixed in the mixer along with water. The mixture is poured over different mandrils for ,;,~!2r~nt Ji.imctcrs. Tilt: pipes arc dried in the ope"n. The dried pipes are finished by wheel cutters 38 Observations. (a) The employees are exposed to dust during mixing and at the finishing operations. (b) No arrangements have been made to provide respirators at these places. 14. Lacburam Balaram Kunavat - Beawar. The unit employees about 45 women and manufactures bends and othar sanitary fixtures. Asbestos powder and cement are mixed in tagoras manually, along with water and the mix 1 used for mak'ing moulds for bends and other fixtures. Observations are similar to other asbestos cement sanitary-ware units. 15. G(ae)neMraol stOobfsetrhveatpioroncse. ssing operations arc heavily dust prone. Mixing and finishing operations 1: A.C. sanitary-ware units are also dust prone. (b) There is neither dust control system nor any dust suppression arrangements, resultinf stos fibres. Both the gcnw idnusvt ilseuvaelllsy ahnigdhasdbuessttolesvfeilbsrethdaut sctelretavienlslyarweoubloduinndcl~utdoe absebehigher than permissible limit> A study of the measurements of dust levels is recommended. (c) Rpreoctoecmtimveenedqeudipwmoernkt parnadctictheesi,r wmhaeinntedinuasnt cleevaenlds, tahree phroigvhiseiro, nreoqfucirheanpgroevriosioomnso. f pNcor>osune::: facilities exist in these units. (d) Under the above conditions, settled dust is seen every where which can increase backgroun. dust counts. (e) No medical check up is reported to have been carried out whether asbc,tus-rdakd c of a general nature. The Team recommends the same. (f) The Team observed that some young persons were employed who stand a higitcr risk of a dust related problems, including those from asbestos. (g) General safety standards also Ieave much to be desired . ..~ .. 11 '~! 39 rn t ion,.._- 1nonuaAD VISITS TO ASBESTOS FACTORIES lN HYDERABAD AND BOMBAY APPENDIX 'B' lrY fixtures. ~r and the mix is; ,.hbttfo5 Cement Products Factory : 17.1.85. 1l';..t.~t .ti..&'!Jb;~lriooniftiocctrhs eviTsietaemd tMhisemFbaecrtos,ryt.he Director of Factories and Boilers of Andhra Pradesh and ling operations in.' ments, resulting\. ~oth the general;. ~ermissible limits.. . ' vision of personal rooms. No such'.: rcasc background : , 1sbcstos-related or: higher risk of all T!<l: T~.11m Yisitcd the Plant and observed various operations in the manufacturing process. The asbestos 1rt frJ IQ the Edge Runncr Mill in entire bag form. The bag enters an automatic bag opening machine ~ ~rdt the fibres arc dropped in the Edge Runner and the empty bag comes out separately. Water lt; tpn:clkd io 1hc Edge Runner Mill to make the fibres wet .to avoid generation of fibrous dust. The 'tlf."1 !!ibrn arc mixed and then used for blending. The Team also observed a new bag opening machine 1V'~t bl got an observation glass window. The fibres in the wet slurry form are mixed with cement 11i'&k~ .u;; further used for either making asbestos cement sheets or pipes. Handling of asbestos, from OJC: ~tdng nagc to the wet mixing stage and after making cement slurry, is a closed system. '7\i.t <i cuu.ings of excess sheet are collected and sent back for recycling. The operation of finishing d ri':r -;al also observed. The operation of cutting the cured pipes is done by circular cutter which ~ ~.!:I dkctivc local exhaust draught arrangement. Similarly, socket cutting and the turning machine h ~ ~-idtd wi1h exhaust draught arrangement. 1\ic t-"'tefJ h.u installed central enclosed filter bag system for handling the i).;: diffnrnt operational points. The factory has also installed a central static cilr.t."l!:lJ:: by suction the spilled asbestos from all the working places. exhausted air from vacuum system for The ~bmatioa of the broken sheets are done by cutting. l tcr ipr.ay to suppress the dusf. This cutting operation is provided with MtlcaJ Surveillance Unit n..: unit I~ ~quipped with X-ray unit, Micro Processor Controlled Recording Spirometer and a .a..l'<OrtM) 'Iii ith a full time doctor to implement the health surveillance programme. Records :jl..::;Jtii:~ .&ii: 1.cpt ~qH:rate/y for every employee. elincal of the t .e1iroam<n1al Control. , I~-" (,1mr.1n) has regular environmental control system. Audited and required records arc t'::_ ......_.u S<aJ., ,hhcto~ Cement Products Factory : 17.1.85. ;.'.J ....... n-.i:- Cc.wt, then, visited a small scale factory engaged in manufacturing asbestos cement pipes. ::er .;:.>hntc~ package is charged into an enclosed Edge Runner Mill manually. Disinterated asbestos n .:L:JL:<.lcd at the outh:t of the Edge Runner in bags. There is no provision for an exhaust fan arrangec ..;;:-.1 ..;~ th('. inlet or the outkt of the disintegrator. Opened asbestos fibre is manually weighed and t!,~.:-.1 10 gunny b.tg~. Asbc~tos is then mixed in mixers with cement to form slurry for manfacturing t,;<n. Tr.i:: ,>p..:r;1tion is of wet type. The pipes are cut to size by use of a circular saw. Dust is :ir:z.tr.i.t~d Juring this operation and the workers were not provided with any protective equipment. u S<;--.lc NonCement A~hc.,tos Products Factory. T':'.t< y"_..m :hC"n visited thc factory engaged in the manufacture of clutch plates. Abestos fibre is kept ~ ~..:,.,-r:.~J Jrucn). A~be~to~ is then mixed with phenolic . resins. The mixture is used for making , ' t~.,1 .;t1 rbtc} by use of power presses. The formed clutch plates arc then subjected to grinding '"-~,1.1ioru where there was no draught arrangement. 40 BOMBAY 4. Non-Cem~t Asbestos Products Factory : 26.3.85. company manufoctureo, The Study Team visited this Factory in the forenoon of 26.3.85. This CAF jointings, ssbestos textile products, mill board brake linings/clutch facings (friction materials), etc. (a) Friction Materials/CAF Jointin1?s Plant. rials and CAF Jointing were cesses observed in the case of Friction fed into the Mate mixer, along with other chemicals Twheet pmroacneusfsaecstuwrihnegreporoncefitbhreesasgbeetsetonscafpibsruelsataerde with wet binder used--wet resins for frictioent and the wet binders, the terials and rubber solution for jointing materials. The mixings come out he of the mixers Iinings/sht:ets in w are 111 ma conditon and all further processing including forming and moulding of t baked to get the final form, shape and size. wet form. The materials are then cured and are fed were observed. In the case of the Brake Lining The mixing operations awsbheesretoassfbibesretobs afgibrisescuartcmanually and charged into a bottom opening terials Plant, the pre-packed bin along with other raw materials, including the binder. This bin is raised gative and the raw ma pressure. fn the case xer body which is provided with sufficient ne hoppers of the mixers with negative ~uction at aorfeCcAhaFrgPeldanitn,tothtehaesbmeistos fibernessuraerse nfeedgliignitbolethdeust emission. In both cases, the fibres dust lcvd the feeding end itself, which in these operations (as per management records) is well within the 2 fihres/cc level recorded d facings so produced, are then machined to dimensions in special purpose grinding remove swttrf Linings an machines/dnlling machines where adequate dust collection systems are of provided to jointings, the sheets are andd\lst f'roduced in the machining operations. In the case bsequent finishing involves only cutting to size cured in the calenderiwngheprreocpeossssiabnilditythoef sruelease of dust is negligibk The Team observed that system~ with scissor guillotine, g operations were provided with eleborate dust collect10n all subsequent finishin TwhheerTeveaemr itthisennecveisssiaterdy. the Asbestos Textile Plant or this Factory. (b) Asbestos Textile Plant. ent grade of fibre are received in pressure pack.ell the manufacture of Asbestos Textiles, anually and differ fed into blending hoppers with negative Sllction ,tt l11c' In bags. These bags are cut m end itself which does not allo..y any fibrous dust to come into the breathing zone of the blended fibres an: feeding operators. The blending operation is done in a totally closed system and the conditions at the b.tgg1ng sta~; !' ' ~-~ re-bagged in polythene bags manually under controlled suction .k' ,;' ' lended fibres arc then fed into the hoppers of the carding machines which arc all mainttic strips. Ai.kqu.1t~ .i::'.' The b tal enclosure of flexible curtains made up of overlapping plas perator~ required to work m~1ci<: ti: ,..... . asuin.::e:tdionin itso provided on the various carding machoinnetsh.eTmhaecohines are required to wear 011-n ~< .'< reenscploirsautroerss.foTrhemacilnetaennianngceoafnda/noyr ofitbhreer wdroorpkpings inside the enclosure is done with the :: i I' A:' help of centralised vacuum collection system. rried out using a totally enclo-;d str1pp noted that the card strippvienlgocoiptyerastiuocntioins ucnait. This arragement enables tl1e c1rJ It was also ing attachment connected to a high ration to be carried out in such <t manner where dust from the rna111 cylinJ:.:r- strippmg ope of the card are collected into a bagging unit for easy disposal. arrang, The carded sliver is then spun on spining frames which are provided with wetting roller ssed is in r..:a~onably w~t qag emanat10n is contained. The frames yarn so proce at the time of doffing yarn arc a!~o ck~tn2c amndenntostoptrhoantethtoe dreulsetase oftrd.'.ul!sits.cdThveacsupuinminsguction system. Further, th2 processing like pb1ting, any spillages with the cen i ~- -,.. ; cturc board ,_ 1-. ~ i F ,J were ~ ~- micals ~ 1iction ~: f n wet r: r arc in F zc. !f,-- Lining jt'i. .. )ening ~- tcrials ff it c case ,!_;. ,_ ion at t,.'l t t level ~ cl. t. t: inding "k swarf ii'3-~ :s are it to size ~- d that I[ !':' ystcms f.' f 41 ,, c.Hing arc t:n.dl;. Jm:d cJrricJ out in wet bdorc packing condition. The finished product, viz, cloth and plaited packings arc J;,i.ll process machine work in polythene wrappers and water-proof stations viz, carding, weaving packing paper. All the indivi- 1c .\\\Jnehdicdaul-rSucnoellielclatinocnea: rrangements which are r;onnected to thaendc/eonrtrpallaiisteindgduhsatvceollbeecetinonpsryosvteidmesd. Tr.c <. ompany nwintains 1r.dud1ng prccmploymen extensive records of health status of its employees over several years pslmonary function t records. These records include tests. All the employees of the clinical examinations, chest X-rays and Comp.my Medical Ofllcer. c0mpany are periodically examined by the 11&1 t~tiroamenral Suneillance : D..:1 t _level monitoring were also ;'t...'"i:c:Bing stations. They were observed to be maintained by the Company at the various e-.r~:aurcmcnt equipment. also found to be well equipped in the areas of dust monitoring and ii_b;h;e,:eCtohmeipr :sintryeeptroanviddewsoerakchclootfheitss seempaprlaotyeeleys. with the twin locker facility, spaced well apart to A.~01o Tutile Plant : 26.3.85 , H..t Tc.am vi)iteJ an Asbestos Textile Plant at Bombay in the afternoon of 26.3.85. Th<' prc-p.ackcd asbestos ;>t.int ~nd the blende bags are manually cut and fed into the Feed Hoppers of the blending it''' rdcd at the d fibres are hoppers appeared conveyed pneumatically inadequate. to the Card Hoppers. The exhaust Cttrenn:!inimg pmroavcehdinewsitahreprporpoevridoevderwlaitphs ptolaastviocidculretaakinageens.closures. The system of curtains could have .-\ pit underneath the carding machines having considerable droppings whic is used to collect droppings from the cards which was ihould be performed with h are reported to be periodically personal protective equipment. cleaned. Such an operation Tbc Team aho observed spinning and rntcrrng che spinning/doubli twisting operations where the yarn was being wetted before ng flyer. f.niodically clean the frames. The Company has installed centralised vacuum system to rSro,m. aereoflothceatseedctiinonasnootfhtehre ffaaccttoorryy, wwehriechnothtewToerakmingc.ouOltdhenrotopveisriat.tions, such as, Tbc Tc.mi could noc sec any medical examination facility in this Company. weaving, plaiting I th ei tf; trirp-~ card { r nd er~ l !ange-J :.tagel in;:-d,c;; ing/or~ r,_ 1 hit i' ;i imall unit, with Jess than 150 workers. l t e blending opern ti on is done in ;1 totally enclosed system and ::-ik :lie hoppers the blended fibres are then fed of carding machine by pneumatic conveying system. Cerr.:il vacuum and dust .:~ 11 s-n havin~ a ~ystem of extraction plant is installed on a German dust extraction specialist 1 f'~ rH in the carding is pipe Jines reaching all equipped with devices the working areas of the factory premises. ol<\' 10 ihe central { ~-<"~_. 1100 dust "fibre vacuum cleaning to extract and transfer the dropping~ pnPumatiplant. The dust extraction plant clears card stri J-1!. Jibrc ;inJ from droppings. the main cylinders and keeps the floor, machines, pping walls etc. clean of Hie management mentioned r~i~'r.,tiM~ :ire that open1tors are provided with Ori~nasal also provided wherever exigencies of work so demand. \\ ...rhr< ar(' pro\ided with two sets of lockers away from workplace. respirators. Airline 42 DETERMINATION OF AmBORNI': ASBESTOS Frnrn: CONCE~TRATION IN WORKPLACES BY UC! iT MICROSCOPY (;\1El\1BHA'.'iE FILTER :\IETIIOD) 1. Introduction T,1e airborne concentration of all types of asbc<;tm fibres is determrncd ays produce comrar::hk res. '.ls '.'.l:.r b,it experience has shown that thisifmfeertehnot d wdoorckserns.ot aTlhwese differences c:1,1 :t_ ::;,: c'.11c \,-, : b'! difkrcnt laboratories, and by d ration of sample, optical counting :rnd other factors. Ti:: d ffcrc 1k1", .r; 1, '..' .1!.: s,.mpling, prepa l tboratorics and counters can be minimised by strict adhcrcnce to these :tnc'. _-cir:,1, c;1 proccdu res. This method applies to measurement of the number concentration ol <11r:io.1 li' :. c1. :ounting criteria. icable for routine sarnplmg and sample evaluation 11cc1s,:11 y to ;1\:-.:\ 1: This method is appl exposure to asbeHos fibres and their control in occourpatpioarntaicl uleanrviro1inhmreocn c. .:,.Jt \:ct'.ro:cosus 1 '' identification of cornpos1t1on or characteristics asbestos. ethod has limitations when applied to samples contam1n:_'. r ,1tv l' ,1c;c,1:::: :: c: 1_ The use of this m uld not be implemented without a full qualitative uncl,_rsu1m\1n tic of saP1p :c, c '.'- J'O .. , , , aTnhderceona~rccquaevntalnyet~vhoof methods available to csltcatellrormgrnacphcyometpco. sition microscopy, electron-m1c1w;copy, X-Ray cry In this mctho1c1~aflolrmpaatritoinc,lestocobme pcloyninsigdewrietdh athseasdbecfci,ntoeds fgiberoems eatnridc ccoounndt1-t:1d,l.,: ,c1,c,',. <.: "1 "t convincing under c~umatc~ of <hbcstos exposure ari.: min1rn1scd. J. Ct>neral \lcthod De'>cription mcasurcc\ quantity of :11r throu)2ll :l 111.: .';;.t1i: A ~ample is collected by drawmg a g pump. The rnembr<Jnc \iltn 1~ later t1:1n .n:~1c,' 111:l a battery operated samp!111 tically homogcnous specimen. The specimen is then examined under,';" --..~ra,,: ti ::~t-, op and the fibres arc sized and counted. The results are expres<;cd as rn ,J J. filter and tilt: mc,hu:, '.:l .:. L of air, calculated from the number of fibres on the 4. Sampling Apparatus Anti Technique 4.1 Filte1 filters (m1xecl esters of cellulo<>c' ur ccllull1Sc; ll't:c'. 1 , 11 \ Membrane pore c,i;e w11h 25mm diameter should bc u,L'.d 4.2 Filter Holder Jt 1:, necessary to use an op~n face 1ilt,'r Duc to dc,t~'n ,1\' ::;~ :~~tc ,,,,_,:: "t ulcl bc u ,: -:- .: ;rn1 : '"' ,. filtl'.r holders, a supporting pad of largn but1on of pore ,11e, c,iw air pa'>'>l11g through tl1 :11 :111:," n:c ::h : - pad 10> to cnm,ucdreoapnenevfeancedd1~ftilnter fitted w1tll a ptotcct1vc mctal 1:c cu'.' 1:1" i1..: 1 1, oll~:'.>''t' 1Jlillctesrrfcrcoomrn aacrycid1fenptraolpedramcaargee 1santdakceonn,taamndmcu1stc1oont cuBwult rrcedcte:n;,-t, ccvr11,:J!L;1,,,c:r;1.1 ~ (, "'""cmcnl ,,: .: 1 r is unnecess because of electrostatic charge it develops clllL' ' 1 43 IX 'C' .-.... 1ethod 1 used tion in ults of ;ontrol ined by :* 4 L ,~:r c::;.:c ~1.ls ::.ho"n that fixing fibre to the filter surface with cytological lixatives or other type t ~:.~ ,, 1' un:icccssary and should not be done. :: : :tr:,~: ,ni!d b<." tran-.ported in closed holders, which should only be opened immediately ::.:.: ;.i;~ .:nd sr.::.ikd immediately after,vards. .,.1 1)r r::: ..,:;c:n;:l1\C method is to transft:r the Jilter to a petri-dish in the following way: In a dust free J' Jc. _iw~ :Nrcp), c:irt:fully remove t:ach used filter from its holder taking care to grasp it "'" ~1 1..0.tlp.1;cJ r.:dgr.:. Place the filter, dust side up, in a plastic petri-dish or similar container ~ ". . t , r t ;1iccc., adhesive tape attached to the unexposed edge. After transporation, ''! '. :~ :.:.in r~ c:t~ily r1:111oved from petri-dish with a surgical scalpel. ~ ~'.::.'.:tr l:,1!\kri or petri-dishes into a rigid containers with sufficient soft packing material ;':~'<"';: 'f-.di crndiin~ and vibration of the filter. The samples should be unambiguously labelled .. h~ u .o :c . ., ~i oe~ c..sary to cnsu re that filters cannot be accidently reused. The filter surface , ni'e'. =-,~ h.- mul;cd for the purpo-;e because of risk of damaging the filter. ,ersonal rermit pes of. )articles ; sample.~ ig light: )f other - c ~ ing that' , t neans of~ nsparent ": r~ ;ro>:ope' 1'" millilitre~ 11npled. ~ itii i~ crorneter,i. L }:. in som{. 1pportin"( 1r.: author~~ 01k otect tht c of c x .he filte{ :::<: ~ .... ;- <a''~ ~.~:r.:::. upcr.ur.:<l pump mu~t be usc<l for, personal sampling. The capacity of battery ~' 'h~ :< ..... ~; 1:1cn: t" .ipuatc continuously over the chosen sampling time, Thh flow must be ,, i "' ~ w .0:~1 and !tntat1vc criteria therc must be no visible vibration of a rotameter float when ' .... ": '. u " hc::i;m.:tcJ to the !iltcr holder. Although some pumps are equipped with pulsation :....:,::~ ui c\tcrnal Jampr.:r may havc to be installed between the pump and the filter. Never "~ :. ;. ; .~rr;;- ,,., i:h~ut a filter. Tht: connections ~hould be leak proof. ;1 ~-..:er r;~Jc!\ ,)f personal samplc:rs have ~~ ~ -~ ~'C r:cf1:rrct.L automatic flow correction devices. Such pumps T'.\.1 .!L tl!t~ ~~M be Mi,il'.J.acJ :o I litre per minu1c (this gives approximately 4cm/second face r i.A' T~~t f.,: n~c t!.,....,tJ t>-c du:d.cJ .nlc:.ul before and after sampling; if thc difference " , .. '~r 1l;t;'!l >\!' tr-.41 lb.C. :QUui r.,1.,.. Lale. Ille s..implc tnU>t be rejected. t n ur u.,,, ~-,~ ~t1.:t ~i l.l'U.J I< J.:1crn11nc llow rate of the pump, car,e must be taken to a.,,,, r r" t ~.~.,.. iit ,.... rtte-l.cr .!o-c~ oot c~usc unknown changes to the flow rate. The flowmeter used ,,.,,.,,..,: ~., \'-l\~ f,', :':t.t..l'IUte llo r.:11c to an accur.icy within :!: 5''.~ of the true flow (95% confidence ,,,~, -1 d ,:~ ~.,,.,..arc ('.:d<bt-'1100 sec Anncxu1c l.) -: ~.r.::..: 11 k.~Jin;. \>n ltit.:r ~hould be 50 fibrcs/mrn 2 (i,e. approximately 40 fibres per '' ,,.,.,,::1,::: Ucdctt Graticule Are:tsl. The lowering of the acceptable fibre loading gives . ti. '~d .<ti.,'(\l~i;k ....)dlh:1cnl!> or \;iria11on. ~ ~ ; '\\Uj.M:IUll l.ll<adiog n..r fc,'.tH kn.!tt'lt 'huulu not c:-.ccr.:d a maximum of 650 fibre/mm 2 (5 fibres/graticule area) for ~o..i>~'lll.iJ '"~ ii\U,\lhO~. rJu:: u~.:1.1gc liltr.:r loading CXi,;ccding 5 fibres/graticule area, tends to .;:;.~:'! ..,, 1rnda nlim-ll1011 and >l1<iulJ bc treated wit4 caution. This may have to be further ri,_:;;...:,t.1 t" .H'i .\YC:fnt:c of I tib1c,gniticulr.: area when mixed <lust agglomerates are present, g,,_: n::; ,,.~tf,:l:mi71 he Joublr.:<l 1( only fibres arc prcsent. Average filter loadings exceedmg - :'.~~~~ !'"~rh.Uh~ .1rc.i rnu5t b~ r~ji.:i.:t<:J. 44 or 4.7 Blanks. for every 25 filters in !he batch, s, ;,:c~ c 11: For each batch of filters used for samplmg, and he same treatment as for normal s,tmp Lo, but \,1tL,;1l ockc... Ir 111: filter which bas been subjected to t drawn through it, or havrng been attached to th, w ~'.1nn!111~c i:,1d d'' ' 1 cap removed, havmg air hre count greater than 3 fibrc/100 graticc:iuul~:e::aoref'atsh, ethceonetnatmirienation. \'.'hen 1',c >1 : 11 rt yields fi be examined carefaurlelay~toandfinadlsotheexceeds 10'.';, of the aclu: l ':'mrk 1, " ac..,,!;t:tiJl~ ; i; dure should exceeds J f!brcs/100 graticule d by the blank are not consi,!crc il; graticule areass, utrhee. sHaomwpelevserr,etphreesdecntteermmat1odnexpmoasyur~elilils lbeses tuhsacnfultluLt : r ,1;xr.~1.c1:1,t1t:cd J' owfitwh otrhkeerhyegxipeone standard (e.g. if the estiismaatceonservative estimate cc 11pl::t1: .~ , even with the contamination then this filter was 15 fibrc2./lOO fr. ;icul~ : :c",: .c:. For example : The fibre count of a blank fibres in 90 graticule :ircas (1.e. l .:20 libit:s, ::: ,:"'. area) while the sample yields 108 Blank Count 0. 0. J5 x 1()() = 12 5;;, Sample Count ,'U ::-::::-- 1.?0 rejected. Furthnmor-, b~c:; ~ 1: As this percentage exceeds JO, the sample is the cause of contaminGtion must be !,wrd :'1 1 1 ''' exceeds 3 fibrcs/100 graticule areas 4.8 Rc,~2mmcndcd Singh> Sample Duration. tions as detailed .fl .;.c;, l'.1-: d1:~. ' Takrng intopleacmcoauynbterhdeetefrimlteinr edlobaydianpgpliccoantsioidneroaf the following forrrui:t single sam A L t= a Cexp. r .... \, '~ ti. !, u:: ) lu lU'. 1~ > ll c ::r;, ,,, th 1" t = Single Sample Duration. fibres/graticule L = reguirnl filter Joadrng in A = effective filter area n11n2 a = graticule area mm2 an:a. rCe=xpf.lo=w aravteernmgel/mfibmre. concentration expected to occur chm ''.~ i h;; '.-. (llbre/ml) tion of single sample duration, the: fc-.1:.i<.'':n~~ ul :" 1. not r,y. ,'' l'. To provide guidance m the selec durations based on 2 lib1cs/graticuk area. if it :, tc Ix nnd..: wl1rJ,t ri_ ended single sample mm1murn and maxmrnm durations allow a choice not known : r1d th..: t11: values, thc: ithin the constramts of 4.6. If the conccnutlrdatp1orenfeisrably be th:H rccrrn:1;1c:H'..: .. 1.11 w ingk Sarnplmg Duration sho sampling the S limit. ---------- "-~,............, ........ ' .. -------------~------~-S-in-g- le- Sample Dui at ion t llf11UI11 (.~>! Expected l11Jl fibres/ml. lull c,hifr 0.1 3.3 hours 3 llOllh 0.5 4200 mmrinnuuttcecs, l455 mhorunru'.,tco 2 10 minutes 20 minutes (4) 10 irim:tc: _, 150 ((44)) JO mi:1utes 11 20 45 nc unused", hav1n~,thc llis 'l .k ttcal prc1ce1ank count : count,' io.; asscssmen~ complianc: ' rcgulatiot 0. l 5 fibres 2 fibres/graticule area. 5 fibres,'graticulc area. 0..1 fibres/graticule area equivalent to 50 fibres/mrnz. Sampling periods shorter than 10 min. are not recommended. -.::r::1lrn~ time should be measured within 2.5%. The timers 01 counters installed in some ;- . ::-:r<; ;1rc not always reliable. t "' ~.imtliing Strategy and Records .: , "..Hious types of sampling ~chem es are given in Aanexure II with advantages and disadvan... ~; 1\ll data necessary for the determination of fibre concentration must be recorded along.. :' 1mplm~ details. An example of sampling and counting re(ords is given in Annexure III. blank COUD! rccted. ion for each i i ..., unplc !'reparation -< 1 1 Cleaning Slides and Equipment Clc:in conditions should be maintained at all times. .\ Jirty preparation area may result in sample contaminaticn and erroneous results. Clean slides Wltl1 lens tissue or industrial paper tissue and lay them on a clean surface, ..: .g lens tissue sheet. It is good practice to clean each coverslip with lens tissue immedi<dt ly before use to ensure that the surfaces are free from contamination. \V1pe ~calpcl and forceps with lens tissue and place them on a clean surface, e.g. kns ti~sue. When mounting a series of filters, the mounting tools must be wiped clean b;;forc dealing with each sample. nple Ouratio !Ists recom: ble to use th! still remain~ is complian the appropri; 1aximum (2) 11! shift hours hours hours hour O minutes .0 minutes ~ l :! Filter Sample Cutting ~!trnntrng of the total filter is preferred. If it is necessary to cut the filter, all cutting ~hnuld be done with a scalpel using rolling action. Do not use scissors. It is recommendc1\ that the smallest piece mounted be wedge-shaped, approximately one quarter or ,ine third of the filter. ~ t 3 :\Jaunting the Sample h'r mounting use the acetone-triacetin method as described rn Annexure-lV, unless ,1 modified refractive index has to be used. WARNING :\cctonc mounting should be carried out only in a fume hood or fume cupboard. On 110 occasion should it be conducted in the vicinity of an open flame. 01,rical Hcquircments ~~ 1 Microscope Equipment The microscope is single most important equipment which can give marked variations in results of counting. Even microscopes of same make and identical specifications can gtvc quite different performances. Thus it is necessary that performance of microscopes ~hould be assessed by means of HSE/NPL Detection Limit Test Slide Mar1<-II (Sec Anncxure V). Prorovidcd detection limit criterion is met, small departures from recomm..:ndcd specification can be permitted. It is also important for newcomers to consult cxrcricnccd users before selecting microscopes for asbestos dust determination. The nt:ccssarys pcc1fications are as follows : f.i !1 ' ' ; -,_ ,,] ~i 2J .,,.')Il '\ ~ 1 1 t:I ~ J ' } ! i f !;; I !I ,, J. I I ' i ! ' I I ll J I I. l l I t l i:l ' i f i l ,i 3 I , ; 46 (a) Light Source: Koehler lllumination is required. A built-in illumina:or is alway~ prcf.:tablc but an external lamp with a plain mirror can be satisfactory. A variable light intensity control is necessary for both methods of illumination. (b) Substage As~embly : An Abbe or achromatic phasecontrast condenser incorporatl'd into a substage unit is required. There must be a means of centring each condenser annulus with respect to the phase plcite in the corresponding objective and a means of focussing the condenser. (c) Stage : A built-in mechanical specimen stage fitted with slide clamp~. and X-Y displacement is requied. (d) Objectives : A rotating nose piece fitted with lOx and 40x objectives, must have numeric.\\ aperture (NA) of 0.65, achromatic. It should have a phase ring of not less than 65 percent and not more than 85 percent absorption. Although either positive or negative p\nsc constrast is suitable but positive phase contrast is preferable because it gives briphtn image. (e) Eye pieces : Binocular eyepieces of compensating type are recommended. They should be chosen to give a total magnification of between 450 x and 500 x, preforably 500 x. A1k<ht one eye-piece must permit the insertion of a graticule and preferably be of focussing type. The use of body magnification changers is not recommended. (f) Graticule : The graticule recommended for this method is the Waiton-I3eckctt ci 1cubr eyepiece graticule. Its actual diameter when using 40 x phase objective and appropn,1te eyepiece should be 100 um 2 um. (See Annexure VII). (g) Accessories : (1) Centring Telescope or Bertand Lens-is essential for checking that the phase nngs 1n ll!e condenser are centred with respect to those in the objective. (ii) Green Filter-is necessary to ensure the best phase contrast conditions bcc:aw.e tl:e optics a1 e designed for this wave length. (iii) Stage Micrometer-must be subdivided into 10 um intervals and pr1?faably bc one millimeter long. (iv) lvficroscope Slides-should be of the best quality. (v) cover Slips-of thickness to which microscope is designed a:e C<,SCJltial. lnco:TL'Cl covcrslip thickness will detract from the quality of the final image (Normally ,1cccpt<1ble thickness of coverslip is 0.12 mm to 0.17 mm). (vi) Hand Operated Counter-This shotild have two columns, one for No. or film:" <tnd another for lields. ~ 5.2.2 Microscope Adjustment Principles Follow the manufacturer's 1mtructions while observing the follo\\ing gLt1dci1n.c~: (a) The image of the light source must be tn focus and centred on the ,.:onJcthcr 1r1s 01 diaphragm for true kochler illumination. :u111ul,: (b) The object for examination must be in focu<;_ (c) The illuminator field iris must be in focus, centred on the sample :.nd open::d c>nl; tc' '.!: point where the field of view is illuminated. (d) The phase rings (Annular diaphram and phase shifting elements) must be concentric. (e) The eyepiece graticule must be in focus. (f) Before each counting exercise, the resolution power of microscope must be clleekc:J t detections limit test slide. All microscopic adjustments must be a daily routine. (See Annexurc VI for dct:!lls). '!t~~-'< -1:.... , ' ' ~-.~...i...-.#----!...;._ _._..:i...... _ .._ 1s preferable Ii" sht intensity rated into a 'ts phase plate r displacement :: ve numerical rn 65 percent :gative phase gives brighter 'hey should be :> x. Atleast LISSing type. :ckett circular;'. td appropriate~ se rings in }. : 47 l :z~-tt>I" Grariculc Calibration i " ,,.,mbin:.ition of eye-piece, objective and graticule must be calibrated with a stage micro~"'':., Should any of the: three be changed the combination must be recalibrated. For some ':11 ",;~""'I''\, c;il 1bra tion~ wil 1 change for o bse1vers with different interpupillary distances. .. , ,l..fl!K\IH<! VII). "'~'7:"'.~~~ 'Ob\cncr Performance Assessment ,:,, ~~h: r;nt i::i.pcrience has shown that significant differences in counts occur due to differences ;i :t '"~.,..;,;pi: quality, scttmg up and cleanliness, it is necessary that laboratories following this H' '."'-..J Jwu!J maintain contact with those having experience with this method. TJ.-.e practical ";.,~.,~-:: ""' limit of microscope should correspond to Block 5 on HSE/NPL tc~t slide Mark.II. : l< .. 'r 1r ,,r microscope ~lillcs for comparison with experienced laboratories will help to ensure "' ~1 ~; ..! rc~ults arc being generated. '". ::i: {<~">t.!.;hk 10 determine intra-observer variation to assess reliability of an observer and in case, # !1th~O!My employ~ more than one observer, intera-observer variation must be determined to ':'~'~.!~.r:.!<t< ~ystemat1c variation in results. t .-... f"~tr Sc11nnin~ -t-i...,...,, ~ <:t ,1, tot-1! magnification of lOOx to 150x (i.e. IOx objective) scan the entire filter area. The ,.,..., ,t::t :::>.1rmally covered by the filter holder gasket should be free of dust and fibres. All , i*'<jflj! ~dds ~hould have similar appearances with respect to total dust loading. If the observed 'f,, '""' J~",,,.. m:.irkcd differences in loading or gross aggregation of fibres or dust, the filter should be .,,, ~.,-N3. The filter must also be rejected in case the background dust is high and interferes ~.-\'f ;lt'.'*1!'.liai; and sizing of fibres or the filter shows any folds, kinks, or gross distortion due to ::->;'::Y'';f".:l:' mounting. 1s because c:rably be one, tial. Incorrect'. nallv, ~tcccptabl~: of !ibr~~ anc ",-1 I :r iris or annuh: ncd only to tbt,' '' oncentric. t be checked )f details). .,_,;,:-,1 .l ,_,h~f.:ictory low power scan change the microscope objective to 40 x phase and focus on :t' J'.h,,.e ;t..-nc. Ensure that the phase rings remain concentric. While most of the fibres and dust ''""'J.'H i! the upper surface of the filter, it will be necessary to focus below (say upto JO um) ~,..,,J.: .-..f,;J:'. );; , .. b-oYC the surface. When counting and sizing, constant use of the fine focus 1s ~,;;~~~:~ }"(,,;.rnsc of the small depth of focus of a 40 x objective (i.e. 2-3 um). Counting fields ,,.,;,,~,,;:: ~ ai~Jtcn at random throughout the entire area of the filter or filter segments. In case a .t;,:~,, 1 u !1:H been used for sample collection and the grid obsructs the view the field should r ,,,~d no not count fields that lie within 3 mm of the filter edge or within 2 mm of Lt;\H.l!'f,~t'1 \\orking Condition' ., 1... ., ...:~;~ii: practices and the working environment in a laboratory may influence systematically ,.,,. k> ri..:y uf the actual counting. Some differences may appear when inter-laboratory , ..,,,~,~n~'f" .ire made wl11ch arc due merely to different laboratory lighting conditions, different .,.,, tq .,_,.,J .:.imputing arrangements etc. Different practices of recordmg data may also cause ,_, : -'<::~cmcnl between counters, due to the rate of fatigue of the eyes. ,, ,1 I ~ . ;.-)nl \\riling of data illVOiVCS the re-foCUSSing Of the eyes after each field, Whereas COnti- i,." t(;,.~taing with elcctncal or mechanical counters involves only a single period of ,.,,1 :J.~-v~.a .;,1nt:cntrat1on. ".-<t~'*' Crlll"ria ~1,~1.q~u=.: .:ill particles having the following geometric dimension as fibres :.;;W.11i g:rco1tcr 1han live micrometers and ,!,sm:ur lc$S than ~hrec micrometers and ,r~;rn I;) d1amet..:r ratio greater than 3:1 48 Accuracy is important, and full use should be made of known dimensional standard:;. the length of curved fibres along the curve of the fibre (i.e. true length). [,time1tc When examined microscopically, asbestos fibres fall into four basic groups as follows : Single fibres can be directly classified according to their geometric dimensions. Split fibres are counted as one fibre, according to their geometric dimensions. The diameter of a split fibre is measured across the compact part of the fibre, not across the split part. Grouped fibres are counted individually where individual fibres can be J1<,t1nguishccl. Where they cannot be distinguished a~ individual fibres tbc-y arc counted as equaivalcnt to one fibre if the bundle has a total diameter less than three micrometer~. Fibre attached to particulate matter arc counted as one fibre if the diarnctt:r of the particle is less than three micrometer, otherwise not. Refer to Annexure Vlll for full details. The counting rules are based on the principle of counting fibre ends, visible witl:in the graticule area and dividing by two to obtain the number of fibres observed. Count any fibre that lies entirely within the counting area. with only one end lying within the countmg area. Count as 'Half Fi'.Jrc' any filne If a single curved fibre has each end inside the counting area having crossed the area tw;ce, each end is still counted as half a tibre. Count as many fields as are necessary to give a total fibre count of 100. A rn1111mum ol 2C fields must be counted, even if more than 100 fibres have been observed. It is not ncc''''<ll') to count more than 100 fields. However, errors will be large when the minimum fihrcs cJr fields are not counted. All relevant information must be recorded. (Sec Anncxure Ill !or an exarnpk uf :t dtb counting form). 5.4.0 Calculation of Dust Concentration and Worker Exposure When the following calculations arc applied, tl1e limitation impos~d upon the lLtta by tht sampling and hbre counting methods must not be disregarded. Results sho11Jd not be rnt-:rprctc1 or reported with false precision. 5.4.1 ~glc Values 1he fibre concentration for each Single Sample Duration is determrnecl accord111g to tli- f"ollowrn formula : A N c= --. (1) a n r where c Concentration (Fibres/ml) N Total number of fibres counted. n = number of graticule areas observed A - effective filter area (mm2)-See Annexure IX a = Graticule counting area (mm2) r Flow rate of air through filter (ml/min) Single Sample Duration (Minutes). Estimate :iws: s. ions. The not across stmguished. eq uaivalent ~ter of the 49 .( _, 2 Tim~ Wdghtcd Average Values. \\ :;.:n ~cvcral samples of different sampling duration are taken, calculate the time weighted .. , tr.~gl' values from the single values as follows: CTW = z.;c; t 2: t. C1 tt11++Ct12ts + - r--------+ Ctnntn (2) Cl W time weighted average concentration (Fibre/ml) Single val uc of concentration (Fibres/ml) t1 ,-= Single sample duration (minutes) ~. 1 = Total sample duration. n, -= Total number of samples. l : : rn1glc sample durations (ti) referred to above arc of equal duration, then equation (2) is ,;;~;lititd us follows: within the. CTW =~Ci n _f.1j-C2 +----+cn (3) n ' any fibre area twice, . ' ' J - -t Jt:l.it aknt Eight Hour Exposure Value (Ceg.) ~~ t'.~ 4.~11ft of the worker exposed to airborne asbestos dust is more than or less than eight hours, ,,.,.,,s.: con.::cntration during the full shift must be multiplied by a factor (f) to yield the Concen- .,: v :'.:I !(cql as follows: 1 :mum of 20: )t neccssary . ,1 Ii br,cs or ; f = full shift time (hours) (4) 8 hours. Ceq = f. CTW (full shift) (5) le of a dust data by the' interpreted ~ ' t::H.i s~.:it Juration 12 hours; time weighted average for the full shift of 1.2 fibres/ml. Using equation (4) f = .Jf- = 1.5 Using equation (5) Ceg= 1.5x1.2=1.8 fibres/ml. 1c follow mg f: . ! D;..:! ~hift Juration of 5 hours with a corresponding shift average of 1.2 fibres/ml. Using Equation (4) f= 5 8 = 0.625 Using Equation (5) Ceq =0.625 X 1.5 = 0.8 fibres/ml r::.: icic.ans that the worker was known to have zero exposure to asbestos outside of his 5 hour <:'. ;j I ),,-l l l 1-k.:lition of Ceq for Various Sampling Schemes. i ' f<t;''>n-1\,B,C and D. C.!h:ul.1tc single value concentration (s) for the sample (s) using equation (1). <..'.i.lculatc time-weighted-average (CTW) concentration using the above single rnpccti\'C single sample duration(s) in equation (2) (or (3), if applicable). CJtkul.:.lt Ccq by using the procedure at 5.4.3. value (s) and 50 5.4.3.2 Calculation of Ccq for Sampling Scheme (E) Typ!_:~~ When 5 or more short term samples arc taken randomly through out a foll shift, tlic ti m. weighted-average concentration can be estimated as follows : l. Calculate the natural logarithm of each concentration Y1=ln C1, i.e. Y1 =ln C 1 , Y2=ln C2 and so on. if any concentration is less than O.l fibres ml, replace it with 0.1 fibre/ml for the above calculation. 2. Calculate the arithmetic average of the logarithmic concentrations. - kYi Y=-- = Yl+Y2+----+Yn n n 3. Calculate the cnwirical logarithmic standard deviation (Se) of the logarithmic conccnt1a tion(s) (samplin{/analytical random errors and environmental fluctuations arc included). or r J 4. The estimate of the average airborne concentration is calculated as follows CTW- Exp [ _ - -s22. - NOTE : The above calculations arc used because avalablc evidence shows that rando11 1 intr:i-day variations are best described by a log-normal distribution. 5. Using CTW from above, calculate Ceq as in Scdion 5.4.3. 5.4.3.3 Calculation of Ccq for Sampling Scheme (F) Type -'F' 1. Calculate single value concentration(s) for the samples u~ing equation U) 2. Calculate the items (Ti) for each individual working phase ensuring that the sum of th~,c phase time equals a full shift. 3. Calcula1e the time-weighted-average concentration using the phase time (Ti) 1mt~ad or th single sample duration (ti) in equation (2). 4. Calculate Ceq as in section 5.4.3. NOTE: The above calculations for the different sampling schemes do not imply 1Jcnt1c.ll rcl1:th1- lity in the estimation of the equivalent 8 hour exposure valu: (Ceq). 6.0 Sampling and Analytical Errors 6.1 General Errors introduced into the estimation of airborne asbestos dust compri~<: sampling and an;ilytic.! errors, each of which has a systematic and random component. Th.: application of standarJ procedure and a reproducible routine is the only way of controlling 1nc_1st ot tile.: nuny ~o~nct:s o' errors inherent in the membrane filter method. The following li)t dcs::1ib,s '>lllll~ 01 th_ cJ:;1111.: sources of error. i..._:: 51 -~' '? out II shift, the ti me~ l t Sampling: !'lo;\ rate Sampling time l ~on representative or biased samplings. } ; Cvntam1nation-deliberate or accidental l, :ion is less than 0.1 fibreslt i tSr IS. AJU1lytical : fffc-ctive tilter area Counting area It:. . ' Counting criteria f 1hcr mounting ft1,\r :::-::;,~~:' le logarithmic concentra-~:,:.,., , :tuati?ns are included). M1cruscopc and observers (\m 1.1m1 nation as follows : ' >,}.'."'~ '- now rate \ariability. f ,' fhn.h.Hn fluctuations of the airborne dust cloud. (:, {:t ... flbtr dhtribution on the filter : t: , ?<>cnr.rnJom deposition of dust on the filter leads to gross errors, the magnitude of which r.~ ,..,_n lll't be estimated. Twenty or more fields must be counted to ensure that mmor t ~ .:n cq;cncc from randomness does not bias the result. ,ws that random 11111 adayt,.,". f' f'j.. lt. ation (ll ~ , ring that the sum of these~ , rr=, ,c time (Ti) imtcad of th~v: r;~. , ot implv. identical rcli:1bi- f }, Cecil. tc' } r- L rt. sampling and analytical I, applicauon of standard r of the! m:1ny sources of :s <;.)in: ol th:: cJtn'.11'.ln f, 1. f. { ' At ,,nly small samples of the fibres deposited on the filter are counted, errors arise in the u'1m..1t wn of the total number of fibres on the entire tilter face. Theoretically, the Pois<;on ~mobutiun Jcflncs the variatio!1 in fibre counts resulting from viewing randomly selected ~:'.Jr.ting ticlds on the filter. If a minimum of 100 fibres is counted, and if a P<.mson ..!H1bution is appropriate to the counting results, the relative standard deviation of the fibre ,.:1.lnh \\Oti!d be 10 per cent. It has been shown experiementally that the actual distribu- t...o 0f tibrc counts can depart from that of Poisson, in which case the standard de\ iation 01'nll Accuracy : "4>;:4-1..li~ <lf tile nature of the membrane filter meth.od, it is not possible to know the true airborne :1btc C<>nccntration of a given dust cloud. For this reason it is not possible to assess the likely N.;'"-.r.;u;:y of the method. Even the precision (or repeatability) of the method is difficult to quantify ~..~~K of ~y~tcmatic errors which tend to arise from both intra and inter-laboratory variation. r ;lrn .1~ :1 whole by "randomly" selecting observers and laboratories, these systematic errors dt (n r.11ld,>111 natu1 ~ ~uch that it may be possible in future to provide estimates of empir ic:1~ :~<ia~n 11.c, the closest approach possible to a statement of accuracy for a method with no ~..:>n '":ruc" \'alucs) \fd.; .... orl- ha'> been clone in an attempt to arrive at these estimates and todatc only rartiJI "" .,.;1n1on) h<in: bccn reached. One of these describes the theore1ical Poisson distribution (Sec w<::noo 6.3.:!l a~ t:ontributing a 95% confidence interval of 35 percent for only 40 fibres .;:'<...iOlcd in 100 graticule areas, (!t';~tt .._1urcc' of random and systematic errors add significantly to the uncertainly m estimating :,!~ ~tt'1rn: a\b:>tvs dt1>t concentration. ~~j 1_1 ~~i :d I.J'oo..... lj 1 i -j ' 52 6.5 Limitations of the Membrane Filter Method And Presentation of Results With the parameters specified in this method, i.e. one litre/minute flow rate tection and a minimum limit for an eight filter hou: loading of 15 fibres per 100 graticule areas, the theoretical lower de ractical limit is much higher. It is generally accepted that sample is u0s.0e2d ffiibltreerss/mcal;n hforewqeuveenrt,lythegivpe a reading of several countable fibres per JOO graticul~ acts from the blank, un areas. These fibres may be unidentified contaminents on the filter or artif It must be recognised that neither counting clearing process which have the appearance of fibres. ampling duration overcomes the problem of background dust, when more fields nor increasing s estos is a minimum constituent in the overall dust cloud. There is at present insufficicn: comes so poo: asb determine at what level the reliability of the method be will. not be a single value, but will be a range itnhfaotrmreasutilotsn haavvaeilalbtiltletelaestotmtehaenrienlga.tiIvteisancdleaarbstohlauttethfiisbre concentration. There appears to be genera! depending upon a agreement amongst those experienced in the field, that these limits lie somewhere in the range Xn view of this situation, and the of 0.1 to 0.5 fibres/ml depending on a variety of conditions. ethod, all calculated values of less than 0.1 f/ ml should be. inherent variability of the m rted only as "less than 0.1 fibre/ml." All higher values should be rounded off to the first' repo decimal place, and to two significant figures. 53 -;; ~ f!.-~ mum filter; I eight,._-<\\!!; ANNEXVRE I c:epteL _.1at ~ 10 graticule;: . : from tbe~ _ :r countinc:~ "',!. dust, when~ insufficient~- - :s so x poor~ be a range~ be generalf ,,~11, ~J.,,'. ~ ~ .; .-t , ,;: :'i" .-t, -::i FLOW RATE CALIBRATION AND CORRECTIONS n!crnal flow meters must be calibrated with a primary calibration device. 0f the commonly used variable area flow meter (i.e. rotameter) using the Ou' el IP 00 fuoe The method soap film flow the range n, and thef: JO<J should be; to the first; ;: 200 100 pump w~let + detergenl c:::J ~ nte,na1 tlow me l e t ' ' ;. "-: ~ ~}..>}(: an accurate burette (or similar) of 300-1000 ml capacity. Attach a tube to the ~i.:i~1iiJnl of the burette, and then clamp it in an inverted vertical position into a t~nd, .~tt up the sampling pump complete with connecting tube, filter holder and filter as used .!; l!t: ticld. 11..;-0r.cct the soap film flow meter. Ensure that the system is leak proof. It is advisable : r;ns:: the burette thoroughly in water immediately prior to the test-this removes accu.,~!,.:c<l detergent and also assists in wetting the inside of the burette. 'i.,. it.ti on the pump and adjust the tlowrate according to the internal flow mater (if 7"J:ll~ till a beaker or petn dish with water plus the minimum amount of detergent nei:essary ~. r<rnllt bubbles to be formed. H, momi:ntarily placing the beaker against the bottom of the soap film flow meter create a :,~,!>::: ;uch that it will travel the.entire length of the burettc without bursting. i. \\.:ii :i ~top watch, measure accurately the time that the bubble requires to traverse the tube !'.<t;1tc:cn its extreme graduated ends. ' , Rcpi::it steps (f) and (g) at least twice, or more, until good repeatability of the times is .a ;!HCYctl. A.-rage the times, and calculate the true flow (Qc) as follows: " v Qc=- \\here Qc=True volumetric llowrate (ml/min.) at calibration conditions. Y = \'olume of burette (ml). , -_7 Avcrage time requir.ed for bubble to traverse the tube {minutes). Step~ td)-(i) must be repeated until the desired flowrate has been reached within 5 %. SOTE -Theoretically, the water vapour content in the soap film flow meter air should be LiJ..cn into consideration in determining the "true" flowrate. However, for practical rurposes acceptable accurary is maintained without this correction. i ~ f; ,I. ! 1r,, f if, ~ . . I... [ .. . ~ r j ~:1 tu.r.r...~. f"l,.-:'--Al ,}:<~ ~~~i-~ 4 1~ ~l ,1 r:Jr~ ff;";-': 54 (j) If the external or internal rotameter is used under different temperature conditions than those during calibration, it is generally not possible to calculate the di fTeren t f1owratc that will inevitably result. As all air sampling measurements are connected only with volumetric fiowrate (i.e. flowratc measured and expressed at the prevailling temperature and pressure) and not mass flowratc (i.e. flowrate corrected to standard temperature and pressure conditions), recalibration of the pump tlowrat<.: is essential if it is operated under conditions substantially different to those of cali brntion. Substantial implies a difference in altitude or temperature by more than 500 m or 15C respectively compared to the calibration conditions. ~x~mple : During the calibration of a pump with an internal flow meter a soap film flow meter of 1000 ml volume gave an average of 63.4 seconds for the bubble to traverse its length. What is tllc flowrate under these conditions? Using the equation in this Annexure : v Qc=-= T 631.047060-0 =946 . ml/mm The flowrate, under the temperature and pressure conditions as stated above was 946 ml/min. t# i ~ 55 EXAMPLES OF SAMPLING STRATEGY ANNEXURE II E. J.1 Occupational Samplinl!; All ~;ampling must be so conducted that the results are fibres under typical working conditions for a full shift. the activities for the worker. representative of the worker exposure to Sampling procedures must not interfere with E.l.2 Worker Breathing Zone In order to estimate worker exposure, samples must be taken in the workers' breathing zone. The workers' breathing zone consists of a hemisphere of 300 mm radius extending in front of the face, ancl measured from the midpoint of a line bisecting the ears. E.1.3 Pcrsonal Samples Personal samples arc taken within the workers' breathing zone. Usually the filter is fastened to tb11dctjaocrkmet alappoecl koeft.the worker with the cowl pointing downwards. The worker carries the pump on a E.J .4 Static Samples Static 'amplcs arc samples taken at fixed locations with the cowl pointing downwards. not recommended for the measurement of personal occupational exposure to asbestos dust. They are Point sources create considerable concentration gradients thus causing the results of static 'ample~ to vary considerably over short distances. However, static sampling can be useful if the dust i, proven to be uniformly distributed over large areas. L 1 5 Single Sample Duration Single Sample Duration is the actual time during which a single sample is collected. E 1.6 Total Sample Duration Total Sample Duration is the sum 0f Single Sample Duration taken during one shift (see E.2.3) on one per~on. E.1.7 Short Term Samples The Single Sample Duration for a short term sample is less than one hour. 'r~ ~ T~Ph':ecisfhicodrtastesrhmorstatmerpmle, hthaes sbameepnles daerfcinaesdsumbeecdautsoe biet iosfnaetcelesasastryontoe rheofuerr tdourtahtaitonsp. ecial case. Unless E.2 ~ratcgy E.2.1 General Principles Occupational exposure measurements are carried out to meet one or both of two major objectives: (,1) To assess exposure relativ~ to an occup:itional hygiene standard and to enable better control measures to be implemented. (b) To provide estimates of exposure for epid~miological investigations of morbidity and mortality. 56 lt is well known that the concentrations varqyuirwei,daelyrelibaobtlhe weistthiminaate soinfgelexpodsauyreano<nl faropmartdicauylator ... ~ ddaayy.. IMt oisstmroegreuluasteiofunls afonrd ehpyigdieemneiosltoagnydatordssprreead the sampling effort over a number of days, i.e, less will be known about a single day, but more about the average exposure over a working lifetime. Since sampling must often serve both purposes, the sampling schemes presented in this method cornphasize the single day estimate. It must also be recognised that variations in individual working practices roup. Consequently data from one person result in a distribution of exposure values within any job g the total job group. Any transfer of data must, therefore, cannot be assumed to be representative of be validated by appropriate relative measurements. E.2.2 Sampling Scheme There are a number of following table. As they table mu~t be interpreted and E.2.4. possible sampling schemes, some of which are listed for guidance in the very in the degree of usefulness and precision in estimating exposure, the m association with the qualifying conditions and cautions presented in E.2.3 Sampling Scheme No. of samples per shift Total Sampling Duration Long Term Full-shift consecutive s~mple (~) Type A Type B Partial-shift consecutive sample(~) Type C Type D 2 or more 2 or more approx. full shift approx. full shift 2 hours or greater I hour or greater Short Term Random Samples Type E Systematic Samples Type F .-..~---------- - - - - - - - - - - - - - - - - - - 5 or more taken randomly throughout the working day 1 hour or greater 1 or more plus continuous relative measurement, or 2 or more taken during each spearate phase of a cyclical operation l hour or greater In planning a sampling scheme, it is important to determine : * the Estimation Period during which the exposure is estimated. * the total Sample Duration. * the Number of Samples. To assess the worker's full shift exposure relate to a whole working day. Care must every effort must be made to ensure that be taken to ensure that the sampling period the sampics is not biased by abnormal conditions. Short term samples should be taken at randomking(stdaatiys,titchaellym) etahsruoruegmheonutt rtehseultwshaorlee vwaolirdkionnglydafoyr. If samples cannot be selected from the entire wor the duration of the period from which the measurements were selected. However, relative measure- ments and reliable professional judgement can sometimes be used to make inferences about concentra- tions during other portions of the day. Reliable knowledge of the operation is essential to make such extrapolations. ' ~1 IH'n \( :.ctiic '(, :1 ..: i l l.!l "t.:di I ':'. 'c rr ':ii ( b) I c) (d) If) ,,",,;_ 't- --~---1::-L........: ~~ ~: ~--...:..,.;_..::-~_.::~ .... : .. __ _ 57 r 2.3 Total Sampling Duration and Number of Samples or S:unpk duration is in!1ucnccJ primarily by the reason for sampling, th~ level M !lbrc i:0ncontra t1on to be measured, the concentration of non-fibrous dust and the requirements the analytical -~1ctho<l. Th is may result in more than one single sample being required. The total sample duration _,iwul<l never be le~s than one hour. -~.6 and "1.8 detail acceptable minimum and maximum loadings of fibres on the tilter, which d1ctatc the range of possible sampling times for dt!krent airborne fibre concentrauons. Samples of short duration may be necessary if l11gh background levels of particulate matter or fibres arc present which would prevent accurate analysis. E 2.4 Heliability of Sampling Schemes The main strength and limitations of the various sampling schemes, types A to F listed in follows : E.2.2, arc <ls (a) 1Ype A Sampling Scheme (tv.o or more samples covering the full working shift) permits the most reliable estimate of exposure to be made. When several samples arc taken," the average of the errors is usually less than the single (percentage) error in a single full shift sample. Occasional gross error~ such a<; miscalculations, contamination, incorrect sample timing, etc. arc more likely to be detected by type A than type B. Notc-~Systcmatic errors, e.g. flowrate inaccuracy, must still be taken into account in the normal manner. (b) Type B Sampling Scheme (one full shift sample) is not as reliable as type A because gross errors can escape detcctinn unless evidence from previous sampling is available on which to base a judgement. (c) Type C Sampling Scheme (two or more samples covering part of the full shift, i.e. two or more hours but less than full shift) can be satisfactory if the partial shift is representative of the full shift. (d) Type D Sampling Scheme (one sample. one or more hours but less than full shift) similar to type C except that gr0ss emi,s may escape detection. (c) Type E Sampling Scheme (5 or more short term samples, taken randomly throughout the full shift) may give an accepta~ile indication of exposure but is generally more wastefull of resources and is the least precise of the above schcms. Note that an even poorer estimJte results when the "average" dust conc~ntration increases or decrt.:ascs markedly throughout the day. This scheme should be applied with cautiJn. ~ (f) Type F Sampling Scheme (several short term systematic samples taken during each scpar<tte phase of an operation) c;rn b: used by experienced industrial hygienists to characterise a workplace. This approacl1 should not be used ind1scriminatc!y, particularly by peorsons not completely familiar with the process. Nor should it be used to estimate time-weighted -average exposure unless the results arc verifi~d by continuous rdalivc measurements or other methods (sec E.2.2). ,- 58 ANNEXURE Ill DUST SAMPLING RECORD ta necessary for the aetermination of the fibre concentration must be recorded in a sampling epidemiological studic~. All da record. Furthermore as much data as available which can be of value for should be included. Sampling Details D Instrument Type and No. D Flowrate, initial,intermediate and firial 0 Duration O Sampling scheme used 0 Date, Hour 0 Sampled by Sampling Place Details t i 0 Designation 0 Harmful substances-types of asbestos, quartz, etc. 00 BVraireifabdleescpraipratimoneteorfswwohrkicihngcapnroecxecsesrcise an infuence on dust formation D Work practices ... Working conditions: normal, abnormal :.. AiMrfalotewrial :: wtyoprek,esrizine,dcuosnt daiitrifolnosw, eytce.s/no obvious influence on adjoining ""orking place~. 0 Methods of dutt control Exhaust ventilation Other methods 0 NuVmibsuearloifmepmrepslsoiyoenes for which the measuring value is representative D Personal protection yes/no Type : D Hours per shift 0 Days per week See the following page for Dust Sampling Record. 59 - - - - - - 1 .. .... ------~ ~.-. -------n..,..._*'f-:1<~~------------------.<1.r-~- EXAMPLE ONLY OUST SAMPLING RECORD P:3ce 01 1neasurernent lla1e lJn.1en,;1011 of workplace Code-No text 1n clear block lettering 0<50rn3 D50-500rn3 0500- 5000 mJD > souo 1113 Exnau~;I vent1la11on Oves Siruat1on representative? Dusi conce/"\trat1on Oves Oabove average Dgood Dqu11egood Dbad iII i I r;u1'1lce1 ol ernployees work111g al this working place Dyes lv~eJsured 1n the dusll:Jelen d1r flow t,d101r1111g 't10rf\1n~1 places (.!fU 1nfluericGd I Mr;asuremcn1 was dune I ~2 np.1 ng device 1 I ,\:r liow rate Opersonal D Ono Dyes D sometimes Type ____ Dyes Measuring point No Dstat1c C J atrnospneric pressure rnoa1 t1rne s t a r t e d D t1meendodD S:.irnlc No Sarnplng lime (rrnn l II DL__J f>I C_J [_=] D D Total Flow Harmful substances 0 Ct11yso111e Oouartz 1..,..,C" tihrw Working pnase F1tJres1rn1 [ J Ave1age vaiue [ _ __J [ J [_:=J [_~] [_ _] [=- --] Qcroc1doilte o _ (other) n Mineral wool DArnos1te o __ 60 Appendlx I Counted by Da1e Microscope No Graticule Type 0-bundles x-oackground not okay Dust Counting Record (Example only) l1bres number ol I l1e1ds Area mm2 c F - - - - - - - - - - - =1 L _-_ J i fibres ml In special circumstances 11 is ot value to record tne number of fibres contained 1n 1nd1v1dua1 fields of counting Sample No. The brgcly ['I"C<tt C I :I prov:J 1 be obt \\'arnir i 1\cdo11 ,,liould f l leat1n l f - - = D c = F fibres ml N n c concentration 1n l1bres ml total number ot l1bres courlled number ol t1elds counted effective filter area (mr'1 2) a a'ea of me coun11ng lteld (mm') v total !low (ml) F A (COf\stant tac tor) a 61 AN1'EXURE I\' ACETONE-T RIACETlN-MOUNTING PROCEDURE The following is a description of a procedure f.:>r mounting membrane filters. The device is dling of acetone requires composed of parts available in chemistry laboratories. The han safer -devices arc being dev.elopcd. They may be used largely great care in order to avoid nccidcnts. Still the same slide quality (no washing off of fibres, smooth surface, cl:::ar background) can providing that be obtained with them. l - it ; ! "\ " Warning Acetone mounting should be carrie~ out only in a fume hood or fume cupboard. On no occasion uatity of acetone is necessary. sHheoautlidngit wbiethctohnedwucatteedrbaitnh tihsepvreicfienrirteyd,ofusaen oofpbeonilfilnagmceh. ipsOnilny tahesmaaclletqone is recommended. (a) As illustrated in the diagram below, it is advisable to use a simple condensing column to free opening in the tap must ensure that a bare minimum of acetone vapour escapes. The atkast 8 mm, otherwise the acetone vapour cannot escape in a have a diameter of sufficient quantity when using an open condensing column. When not in use, the acetone vapour outlet should be closed. (b) Heat the acetone to boiling and wait until a moderate-quantity of acetone vapour is emer- ging from the outlet. (c) place the filter, dust side up, on a clean microscope slide at room tcmperature-clcct- rostatie forces usually keep the filter on the slide. (d) Ensuring that no liquid acetone drops on the filter (by wiping the outlet periodically with cetone vapour s<rcam approxi- a tis,ue), hold the ,Jidc with clean forceps directly in the a t for three to five seconds. At the same time move the mately 15 to ter slowly 25 mm ac1o~s from the the outle outlet to ensure even coverage until filter is trnmparcnt. Too little Jil sparent, while to;) much vapour (cspe~ially drnps voafpoluiqruwidillaceftaoilneto) wreilnldedrestthroeyfitlhteer ftirltaenr by dissolvings it or shrinking it beyond use. The ~lide must not be prcwarmcd, as the acetone vapour must condense on the slide for correct cl::aring. (c) Using a hypodermic syringe with a 22 gauge needle, place one th..! to three drops of glycerol development of a "skin" triacitatc (triacetin) on the acetone cleared filter. To avoid r at an angle (see diagram below) a clean coverslip t>vcr the triacetin, immediately lowe onto the membrane. _.0. - (f) Too much triacctin (as indicated by excess liquid emerging from the edges disintegrate to some of the covcrslip) degree. lnsutti- can cause the outside edge of the filter eventually to sult in uneven clearing of the granularity left from the aceton vapJur cient triacetin will re clearing. Further, the refractive index of the mounted s:tmplc will not b~ suitable for ihilitv of very line Chrysotilc fibres. 62 (g) Heating the cleared niter to approximately 50C for fifteen minutes accelerates the clearing process and enables analysis to proceed almost immediately thereafter. Otherwise it is ~ necessary to delay counting for about 24 hours until the entire filter has dissolved under action of the triacetin. The fiinished product will be stable, will not disintegrate, nor be subject to particle migration. (h) It 1s desirable to paint nail polish, or similar lacquer around the edge of the coverslip if the slide is to be kept indefinitely. /12 0 1T 'J'Ot::fa,,.-,,.'/ l rTlm ~ 8 mrn ID 60" Closing Facillly (Tellonl 01 minimum 1n1erna1 d1ame1er 6 mm Hea11ng device w11n 1empera1ure re<J1,1la101 fi'(~! '.)e~ The a r. rt.T (). l ~ COIJ ll1 a rati plal I :2 0 L'Y t l l 1 \' nr t lil:t. .'\let St.:t 1!1l'l Loe: Dct1 g10( On (l) 63 ,,. ANNEXURE V HSE/NPL TEST SLIDE (MARK IIJ FOR THE DETERMINATION OF DETECTION LIMIT WHEN USING PHASE CONTRASI' MICROSCOPY (1) Description The standard test slides consist of identical epoxy replicas (with a refractive index of 1.58) of a Master Slide produced and certified by the Nationa[ Physical Laboratory (U.K.). The epoxy replicas are mounted on a glass slide 75 X 25 X 1.2 or 75 X 25 X 0.8 mm and covered by a covcrslip 0.17 mm thick with a layer of another resin with a refractive index 1.49 in-between. The test objects consist of a series of 7 blocks of ridges of length 8.5 mm fillled with a resin of refractive index 1.49 in a medium of refractive index 1.58. The ridges have a V-shape profile and have a height to width ratio of about 0.1. The blocks arc separated by gaps 20 m wide. A set of 4 deep marker ridges is placed on eilhcr side of the array and a further two sets of 2 marker ridges spaced at an interval of 120 um intersect the array at right angles. The zone of the test objects to be uscn is delineated by by the rectangle bounded by these marker ridges. This zone can easily be located as the field of view in which it is found, is engraved on the covers!ip. This is illustrated in Figures I and 11. The widths of the ridges within each block and the calculated , phase change (in degrees) associated with the maximum path difference in light rays passing through the test objects are in Table I. Method of use Set up the microscope for phase contrast microscopy as recommended for the membrane filter method. Locate Block I (the coarsest set) of the test objects and move the slide to observe aujacent blocks. Determine the block of the finest grooves that can be seen. It is unlikely that all seven blocks of grooves will be detected using optical phase contrast techniques, even on the best research microscope. On othe basis of present information, a satisfactory system will detect Block 5. (1) Available from: PTR OPTICS, Unit D9, Cross Green Approach, Cross Green Industrial Estate, Leeds, Yorkshire, United Kingdom, l.S9 OSG 64 TABLE I Widths of Test objects and Calculated Maximum Phase Change Induced in Light Rays passing through Test Objects of HSE/NPL Test Slide. Maximum Calculated Phase Change Block Number Groo(vem)Width n(ainnodmeegtrreesss)pfaosrsilnigghtthrroayusgh.\ t=est 5o30bjects ~c1 ~l 6.6 (Ji 2 0.77 4.7 j)J 3 0.64 3.9 4 0.53 3.2 an 5 0.44 2.7 6 0.36 2.2 7 --~~~~~- -~~~~"-----------0~.2-5 -----~----"-----------1.-5 ---------~ I I Fig 1 Test slide (76 x 25 mm) epo;y resin replica ----+----1....e + cover slip . . I I . Fig 2 Enlarged field of view + 20 I1nes per set (85 mm h1' gh) - - 1I 1 i 11 65 MICROSCOPE ADJUSTMENT PROCEDURE ANNEXURE Vl Goocl quality phase contrast microscope equipment should be used as detailed in '.:>.2.1. The equipment should l~c rnaintarncd in first-class condition and most manufacturers operate a routine maintenance ~crvicc \\hich includes the stripping down and cleaning of all optical components and the rcplz1cemcnt or worn trnvcr~e mechanisms. Such services should be used unless skilled maintenance service~. can be pIUVJ(kd by counting-laboratory staff. Jn gcncr:I! the following setting-up procedure should be adopted to obtain Kochler illumination and good phase contrast conditions but the detail may vary according to manufacture1 's instructions and the type of equipment. (a) Place membrane filter specimen slide on microscope stage. (b) Open both the illuminator diaphragm (often referred to as the field iris) and the substage condenser diaphragm. (Nok--at this stage the phase annuli should not be inserted. These arc usually based in a rotating drum fitted into the substage condenser unit.) (c) Raise condrnscr to its upper limit, usually within I mm of lower race of spcc1me11 ~idc. id) '..Jsing a convenient level or illumination and IOx. objective focus the specimen. (c) Close down the illuminator diaphragm and focus this in the field of view by lowcrng and r~11Sl!lg C1c condenser. Ceatr._ the diaphragm and re-open to fill the field of view. (f) Observe the back focal plane of the objective, using either a Bertrand lens fitted to tlic body or the microscope or by removmg the eyepiece and using an auxiliary telescope. (g) Observe image of bulb (removing the diffusing disc if one is fitted) and centre the bulb filament--focussing the bulb if possible with the adjustment provided. The image of the: bulb iilamcut should fill the back focal plane of the objective. Re-insert thc d1ffusmg di:-.c if' appropriate. (Note-if the bulb cannot be focussed adjust to give uniform brighl illurninaLion.) Ui) lnserl the correct phase annulus into the condenser system and ccntrc tlm usrng the appropnatl.! adJUStm,; screws so that the phase plate in the objective and the 1magl' of the annulus comcide exactly. Adjust slightly the condenser focussing if this is nee cssary. [n-;ure that the bright annulus image does not extend beyond the phase ring. (i) ncvert to normal viewing and change to 40x objective with no phase annuli rn the condenser system. Close down the field diaphragm and refocus this by appropriate adjutrncnt of the condenser. Re-centre if necessary and re-open to fill field of view. ft \j) Rcpcat stages (f) and (!1) after inserting the phase annulus appropriate to the 40x objcc tive. (k) Revert to normal viewing. 66 ANNEXURE VU SPECIFICATIONS OF EYEPIECE GRATICULE, ORDERING INFORMATION AND CALIBRATION The two sets of counting criteria specified in 5.3.4 include different limiting fibre aspect ratios viz. 3 : J and 5 : J. The type 022 'Walton/Beckett, graticule (1) was designed for the 3 : 1 aspect ratio and has been available for several years. A modified version of this graticule has recently been designed specifically for the 5 : 1 aspect ratio (2). for each graticule, the desired dimeter (d) of the circle to appear as l 00 2 micrometers in the obj~ct plane (D) of the graticule and the overall diameter of the glass disc should both be specified in millimeters before ordering. The following procedure is one of several methods for determining the diameter (d) of the circular counting area : (a) 1nscrt any available graticule into the eyepiece and focus so that the graticule grid is sharply in focus. (b) Set the appropriate interpupillary distance, and if applicable reset the binocular head ad.1ustment so that the "tube" length (and thus magnification) remains constant. (c) Ensure that the 40 X phase objective is in place, and that the magnification changer position (if used) 1s known and recorded. (d) Place a stage micrometer on the microscope object stage and focus the micro<;cope onto the graduated Jines. (e) Measure the overall object length {lo) of the graticule grid using the stage micrometer. (f) Remove the graticule from the microscope and measure its actual overall grid length(lu). This can be done by using a stage fitted with verniers. (g) Use the following equation : - l-a;;-. D = d = ctiameter.,to be specified 1 E-x-am-pl-e -: Step (e) produced an object length of a Porton graticule of 180 .m. Step (f) produced an actural length of 4.50 mm. Step (g) 4.50 mm 0.108 mm X 0.1 = 4. 17 mm Jt is also necessary to measure the overall diameter of the glass disc. In this case the disc diameter was found to be 17 mm. Thus a "Walton/Beckett's graticule of di'c diameter 17 mm and circle diameter 4. 17 mm should be specified for the above example. CALIBRATION OF EYEPIECE GRATICULES (a) Obtain a stage micrometer, prefeably with a scale having two or 10 m divisions and, place on the object stage of the micros.cpe. (b) Make sure interpupillary distance of eyepieces is ;et correctly. (c) Note the objective magnification and any intermediate magnification used. (d) Focus the microscope onto the stage micrometer. :\dd1n; 'til:t t if the l'Y IH~CCO>ol (!) A Rcfcrcr I_')) !\I 67 (c) Linc up the eyepiece graticule with the graduated divi~ions on the micrometer so that lhi:: number of whulc nikrometcr divisions can be counted from one ::;kk of the cyr.;ii2CL' -- graticule g!'aduations to the other. . (f) if less th:111 a whole division remains, estimate this fraction to the nearest micrometer and ;idd to the number of whole divisions of the stage micrometer after converting to rnicrl'mctcr. This totalled result is the projected or object dimension of the eyepiece graticule. Example - . . ..... ,.i....... . . . _ _ . . . . . . (a) A stage micrometer with 10 um divisions was placed on the stage of a microscope. (b) The following diagram depicts the view of the superimposed eyepiece graticule and stage micrometer. Note that 10 whotc d1v1sions span across the graticule. i.e. lOX 10 um. ' (c) The remainder of the I Ith division is estimated as being one third of a whok div1s1on, J. e. thrci: um. i\dding these together yields 103 um which is the object dimension of the eyepiece graticule. Note that if the 1nterpupillary distance, objective, intermediate magnification, or even in some microscope-; the eyepiece i~ changed then this usually changes the object dimension of the eyepiece graticule-thus necessitating rcc:al1brat1on. (l) Avaibbk from: Graticules Limited, Sovereign Way, Botany Trading [,tate, Kent, Eng'and lRN, Reference No. G22. (2) Also available from Graticulcs Limited, but has yet to be assigned a Rcforcnce Number. 68 ANNAXURE-VIII I J 5 v ( Drawings of Various Asbestos A B c D E f (d Fibres Tl NOTE: All drawings are the at1 msaimcreomsectaelre = i.e1. momne. pa The number in the I I I I I I m: ,..,,--. reiagchht dbroatwtoimng cionrdniceartoesf G H I J t< L the number of fib1es l'l~l (as defined) counted. I) Ill I ( Un I i l (a) Single fibres are the simplest of the I I I I I I - Jibr These nt. M N 0 p Q A a Jl l fibres to identify and cou p<1 r They are the most common of measurable fibres as seen on par ( ) y the membrane tilter. Amosite fih1 \ ~ ~ and croc1dol1te fibres gener- ally assume a straight needle- I I I I I I like form. Chrysotile fibres, while sometimes straight, often s u v w x ill(l I assume a curved or curly ~ '> , outline. Fibres which appear T I I I irregular and perhaps "unfibre- like" are counted if they con- form to the basic requirements 0 0 0 0 I 0 of fibre definition. (b) Split fibres These appear generally as a fibre or splitting away from a srngle stem. ic) Grouped fibres These are formed when fibres overlap, intertwine or pack together. The simplest form is when two fibres overlap and cross each other. In this case each fibre in the group appears as a discrete entity. In more complex form fibres lie nearly parallel and appear to originate from the same bundle. A B c D E r ! (, y (, j I I I G H I J Y, 1 K' l J I I I F / I L I I f f< i ~ r M N 0 p a R y I I I I 0 0 Scale L...J 5pm A B c D E lf-[Xl -Y ~ ~ +-2 ~ 2 4 3 4 2 - I ' ~ ' ~ /fl( G H I J K L I 0 0 0 0 0 Scale L-.J 5um '1.:1 69 " ' (d) Fibres with other particle~ This group consists of fibres A B c 0 E F attached to, or embedded in l ~ z ~ ~ ; particulate matter This latter ~ material could asbestos rock, be parent or resins, I I cement, silicates, etc as used G H I m manufactured products. Under the microscope some v ~ J fibre, especially chrysotile, ~ t appears to project from the I I particulate matter with only M N part of the fibre seen. Other I I I I J K L ! I ' I 2 2 2 p Q R I .i 01 fibres (often amosite) arc seen as embedded in the particulate J ' ~ matter. a\ s I I 0 0 0 T u v w x ---j @ . ~ ~ 'vi. ) 0 ~ 0 Scale 0. 0 0 0 1..-J 5pm t I 70 ANNEXURE-IX r , MEASCRE:\lf.NT OF EFFCTIVE FILTER AREA One convenient way in which to determine the area of the dust deposit (i.e. the cITectlYe iilter area) is as follows : (a) Place a small quantity of dark coloured fine dust (e.g. carbon, cement or road dust) into a 2 to 5-litre container with a lid. (b) Shake the container, remove the lid and draw air through a membrane filter and its holder until the airborne dust in the container forms an obvious deposit on the filter. (c) Remove the filter from the holder, and mount onto a microscope slide in the normal manner as described in the standard method. (u) Measure at least four different diameters of the resultant dust spot to within :!:: 0.2 mm. use of microscope object Amongst other methods, microprojection measurement, or the stage verniers have been found satisfactory. (e) Provided that the measured diameters differ by no more than 1 mm, a simple aritlum:tic average 1s sutlicient to provide a good estimate of tile effective filter diam;:ter. (f.) At least three individual filters must be prepared and mean area calculated. (g) Pshroovuliddebdethtaaktetnheanthdreethfeiltearredaiamceatlecruslatdeidfferin ntohe muosrueatlhamn a1nnmerm. , aTnhiasri tahrrenaetiisc tahveenratiglle~ Eikctive Filter Area to be used for calculations in this method. (h) lf steps (e) or (g) produce dliferences greater than 1 mm, close attention should be paid to the samplmg of the dust or to the filter clearing tecb.nique. (i) It is necessary to repeat the measurement of the effective filter area if the type of filter or holder, or if any aspect relating to filter clearing is changed. (j) It is advisable to repeat the entire measurem.::nt procedure every 12. months to ensure that the correct effective filter area is known. d1