Document 7OXjEjRGoQv5KL54rVyVE9NOo

FILE NAME: Asbestos in India (IND) DATE: 1985 DOC#: IND020 DOCUMENT DESCRIPTION: Indian Govt Report of the Committee "To Study the Health Hazards in Asbestos Industry" I'/. P a. Tr ~j Y~V >''3 f7A>-.- C.j V (? >' - C-A'l'-'J \rJ . (r S.No. 1. Preface -/i >^cJ s '"M / ) u t . C ^ i! - h nr-^(pr Q_ S'-. T A B L E OF C O N T E N T S fV\ x->~y I i,^ u- d[ ) ? ? Page 1 2. Summary of observations & recommendations. 5 3. Report of Study Team `A'. 8 4. Report of Study Team `B \ 21 REPORT OF THE COMMITTEE "TO STUDY THE Health hazards in asbestos industry - HC onstituted by the dgtd panel on C0 acI eSTOS PRODUCTS INDUSTRY P REFACE In pursuance of the decision taken 'b;/ the P a ^ n ^ . , to "Study Health Hazards in Asbestos Industry . ri,c terms of reference assigned . . " associated with inhalation of To form,a,c a ^ ,, J genOTl environment. _^ ^ 'rshPStOS fibl* tll6 TTw..r - , . ^ A V or Otherwise of existing legislative provisions To examine the adequacy asbestos induced maladies- ooccccuuppaattiioonnaallllyy eexxppoosseed w. .o.rkers irom risk oi , 0 health .a d safe., in the Asbestos To make other recommendations as appropnat E Products Industry. . jt consisted of The Chairmanship of the above members specially drawn from " J " ' a,,d independent experts in the fie The Committee me. for the firs, time ^ " .'regulator, agencies, the industry of th Committee members is attached. aod decided that the terms of on F * d mc varl0us areas of study, ; , ; e d & then areas of stud, are delaiied ^ - Study Team 'AT under the problems associated w ` " TheSt"dy " " ChaUcrjee, _ ^ ,, study health " brc dust al workplace or in the general environmediba, surveili.nee and diagnostic enter,,. - Sludy Team `B*. under the Chairmanship of D, 0 ,0 . For protecting oeeupa- _ Examine the adequacy or " ^ " ' " ^ ' " bestos'induced maladies. The Team were to study penally exposed workers from the risk of asb ^ Modd Role 123A;other guidelines by" S Government ,, H n 'L . Ibe indiao Mines " I U Which are appheah.e, as a standard, in all .he Sm.es m India , ^ ^ _ Cover m dep.h a,, aspeels of - ^ ^ ^ ^ o T o C t a P o f a 'nd Ic e , of eompensanou sludy was to cover insurance companies regarding insurance cove, for tempo,. V p^rmanenClisablement arising from exposure ,0 ashesios dust. 2 Both these Study Teams met independently several times and collected impoitant data by visiting mines, factories at various locations and/or by literature search for scientific works on the subject and study of regulations and practices of various countries and international bodies, like, the 11.0. The Committee reviewed the progress of work of the two Study Teams during intei mediate meetings with useful exchange of technical data. The reports ol both the Study Teams have now been iecei'. ed and after scrutiny by the Committee are placed on record and appended to this iepoit I would like to thank both the Teams for the great effort in generating this important and useful document and also the members of this Committee for their valuable guidance from time to time I would also like to place on record my sincere appreciation for the untiring efforts put in by ling D.B. Kapoor, Member Secretary of the Committee, but for whose assistance the report could not haw been completed within the stipulated time. I would finally thank the Chairman of the Panel on Asbestos Products Industry for providing me this opportunity to deal with such an important subject. I believe that the dedicated expertise of all the members connected with this report is amply revealed by the qualitative technical evaluation contai ned in the document. I have no doubt that this report will form a useful base document to evolve strategy and plans for the control and elimination of risks in the asbestos industry and other such industries dealing with toxic materials suspected of long term health eflects. New Delhi 9 July 1985. Sd. (D.K. BISWAS) Chairman of the Conimitiee 3 LIST OF MEMBERS OF THE COMMITTEE "TO STUDY HEALTH HAZARDS IN ASBESTOS INDUSTRY" Mr D K.. Biswas Director, Department of Environment, Government of India, Bikaner House, Shah Jahan Road, New Delhi-1 10 OH Dr, V.P. Gupta Director (Research), Central Labour Institute, Eastern Express Highway, Sion, Bombay-400 022. Dr. B.B. Chatterjee . Director, National Institute of Occupational Health, Maghani Nagar, Ahmedabad-380 016. Dr. G.K.. Pandey Piincipal Scientific Officer, Department of Environment, Government of India, Bikaner House, Shah Jahan Road, N e w D e l h i - 1 10 O i l . Dr G.G. Davay ! v Medical Inspector of I actones Government ol Maharashtra, 7 72, Varma Nagar ( )hl Nagardas Road, Andheri (East). Bom has-400 069. Mr. G S. Ichhpurani DDG of Mines Safety. Southern Zone, 11vdeiwbad Dr. S K. Dave Asst. Director, National Institute of Occupational Health, Maghani Nagar, Ahmedabad-380 016. Mr. B K. Sharan Director, Mines Safety, Directorate General of Mines Safety, Dhanbad. Chairman Member Member Member Member Member Member Member 4 9. Mr. N. Venkataraman Managing Director, Everest Building Products Limited, " Ashok Bhavan" , 93, Nehru Place, New Delhi-110 019. . 10. Mr. J.B. Amin Vice President (Works), Hindustan Ferodo Limited, Post Box No. 9213, Lai Bahadur Shastri Marg, Ghatkopar, Bombay-400 086. 11. Mr. V. Pattabhi , Asst. Vice President, Hyderabad Asbestos Cement Products Limited, Sanatnagar, Flyderabad-500 018. , ,, 12. Dr. S.P. Vivek Chandra RaO' Medical Officer, Medical Surveillance, Hyderabad Asbestos Cement Products Limited, Sanatnagar, Hyderabad-500 018. 1 3 . Dr. P.K. Sishodiya Hyderabad Asbestos Cement Products Limited, Ballabgarh, F a n d a b a d (Haryana). 14. Brig. D.B. Kapoor Executive Director, Asbestos Information Centre, 401, Padma Palace, 86, Nehru Place, New Delhi-110 019. ' ' Membe: Membe" Membe: VI e in be i Member S.-ei-u; u SUMMARY OF OBSERVATIONS AND RECOMMENDATION* Observations 1. Main observations arc : i-1 Uncontrolled asbestos usage has been the cause of heaw nnri ^ 1 i workers. Such exposures to asbestos dust may rcsr.lt 1,, a s b e s L l , 2 ? tlielioma. (Para 9 of Report by Study Team 'A'). "** " T TM ` " * *" - 1 2 These diseases liave long latent periods, making it difficult tn rpiot^ valence of disease at any given time. (Par, Z o f ^ * th` ^ There are some reported cases of low exposures in the past that resulted in no appreciable increases m risk A report on the evaluation of risk to miners in Canada on current levels of exposures (50 fibre years) is estimated to have had no unaccentable risfs Z n r uSCPfrt by Study Team <A,)- Such information enables this Committee to recommend the use of asbestos in such places where it can be used under cfintmiip i 1 i SO that ,,re b c ,, e ,Sof this raaterla, continue ^ ^ 1.4 rhe latest scientific thinking favours the controlled use of nnt ,. , inorganic fibrous materials. (Para .3 of Repot, by Study i . L W , " h"' Recommendations `h' r General Environment 2.1 Various studies reveal that asbestos la general environment has no, been found cause - - c ; z z x rx into ; y e ectab e mereasc m rrsk to the people at large. (Para 21 of Report b, Study Team 2.2 sissss - - Mate Pollution Control Boards should make emission standards for the control , r , libre dust in the general environment. (Para 16.10 of Report by Study Team `B') 3 ^ Legislative Regulations. 31 Factory Acts & Rules 3.1.1 framing of rules according to the Schedule XIV and Model Rule m A h,, concerned States is an urgent requirement. (Para 16.2 of Report by Study Team `B ) ^ 3.1.2 All operations and places where asbestos fibre is used should be brought under th > purview o the Factories Act and Rules, irrespective of the size of the workforce or usage ol electric power. (Para 16.8 of Report by Study Team `B'). 3.1.3 Every process and equipment related to the milling of asbestos ore and asbestos fibre should be stud.ed for its potential c[ca,e , l r. b,, rne l s T c T e ^ v proeess/equ.nmem releases dus, that cannot be controlled the desired limb Z S t , sTM " r ch shou,d * cp .<5 3.1.4 Current prescribed level of 2f/cc as specified in Model Rule m A TM m , at the present time. Membrane Filter Technique (MFT) should be used for The 3 men, of the air-borne asbestos bee dust. >,,,, , 6J -ikk '-t.tr glt ji y 6 3.1.5 Measurement of fibre dust levels is u complex subject and efforts should be mode to obtain uniformity within industry and regulatory agencies (Para 16.3 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 a contingency , 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 manufa 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 the prescribed limit. (Para 16.6 of Report by Study Team `B'). 3.2 Mines Act; Regulations & Rules Thereunder. 3.2.1 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 asbestos fibre dust during mining, 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 Factories Act so far as they relate to asbestos fibre dust control. 3.2.3 Asbestosis; lung canccr'and mesothelioma wdien they are caused by asbestos should be notified as occupational diseases under the Mines Act. 3.2.4 Specialised trained manpower and equipment are to be provided to effectively monitor the environmental exposures in mines and medical surveillance system ol the mine workers 3.3 l.icencing. (Para 16.9 of Report by Study Team `B'). For licencing/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. (Para 16.8 of Report by Study Team `ID. 4. Small Scale Industry. Management and control of asbestos dust in the small scale sector of the industry need to be tackled on priority basis. Major recommendations in this regard are : -- Financial : Subsidy should be given for the purchase of equipment needed for the control ot 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.l.C. or other concerned agency should be directed to pool the technology for the suppression/control of asbestos dust and to help the Small Sc.ile Industry to select and install appropriate equipment. -- Measurement and Health Control : The Small Scale Industry should be encouraged to poo! 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 ot the need tor strict tmple. mentation of the asbestos regulations and the health hazards that might arise due to occupa tional exposure to asbestos. (Para 16.7 of Report by Study Team `B'). 5. Compliance of Regulations. 5,1 Packing of raw asbestos fibre should be in impermeable bags and shoulJ be handl.-d as unitised loads as far as it is practicable. ISI may be requested to bring out the Coda of Practice for packing, handling, transportation and use of asbestos fibre. (P.ira 16 11m Report by Study Team `B'h Ffleetive steps to implement the Rules must be taken by providing all facilities to the state regulatory agencies. These include dust monitoring equipment and specialised trained manpowei in order to produce accurate and ieproducible results.' (Para 16.3 of Report by Study Team `B'). _ The industry should periodically monitor dyst levels to ensure the eilectiveness ot the cn'incoring controls. (Para 9.2 of Report by Study Team `B'). _ Government should be liberal in allowing the import of equ.pmcnt required for the use in 5 4 dust mon,tonne & medical surveillance. (Para 16.13 of Report by Study Team `B'). Medical Surveillance All the workers likely to be exposed to asbestos fibres should be covered by a well defined (i. medical surveillance plan with no cost to the employee. (Para 27.2 of Report by Study Team *A'3- 6.2 Health education of workers is an .mportant object of medical surveillance programme. (Para 28.1.2 of Report by Study Team `A'). 6. Frequency of periodical medical examination should take into account age, service ot employee' and his exposure profile which includes his exposure level in relation to action level. ' (Para 29.3 of Report by Study Team `A'). o.4 Medical records along with periodic exposure profiles should be maintained tor 40 years alter employment or 10 years after cessation of employment. (Para 32.2 of Report by Study Team `A'). .C ompensation. 7.1 The employees covered under the ESI Act should also be eligible for compensation after cessation of ESI coverage, as is the case in Workmen's Compensation Act, (Para 16.12 ot Report by Study Team `B'). Employees not covered under the ESI Act should be covered under general insurance, at no cost to them. (Para 14.6 of Report by Study Team B'). Clear criteria for the diagnosis of asbestos related diseases ,should be specified and should be 712 uniformly followed. (Para 14.2 of Report by Study Team `B'). Criteria for diagnosis for asbestosis is included in this report for the purpose of determining eligibility lor compensa tion. (Para 24.1.6 of Report bo Study Team `A'). Criteria for confirming asbestos as caus ative factor for lung cancer and mesothelioma is also included in-this repo-t for the purpose of determining eligibility for compensation. (Paras 25.7 and 26.8 of Report by Study Team `A)'The Committee recognises the .need to designate an agency that possesses specialised training, expertise, competence and facilities to decide the cases entitled to compensation arising out of asbestos-related diseases. (Para 16.12 of Report by Study Team `B'). 7.4 Reuionai medical panels should be constituted to act as referal bodies in case of asbestosrelated diseases to determine eligibility for compensation. (Para 34 of Report by Study Team `A'). 7.5 Panel should have specialists, preferably with knowledge of asbestos-related diseases. 34 of Repoit by Study Team `A'). 8 National Standards/Codes of Practice. 1S1 may be requested to expedite formulation of: (Para Standard for the measurement ot airborne fibrous dust. Code of practice for the packing, handling transportation, and use of asbestos in the factory, nunc and other places. Code of practice for the use of asbestos containing products. Code of practice for disposal of asbestos waste materials, including tailings. (Para 16.14 of Report by Study Team `B'). 8 ftnat REPORT OF THE STUDY TEAM `A* FORMED UNDER THE AEGIS OF THE COMMITTEE "TO STUDY THE HEALT HAZARDS IN THE ASBESTOS INDUSTRY" , CONST!TUTED BY THE DGTD PANEL ON ASBESTOS ___i\mT ICTDV PREAMBLE , ,. th(. n riT D Panel on Asbestos Products Industry to consti- In pursuance ol the decision taken y Asbcst0s Industry" , a Study Team designated as Committe ,0 "Study the Health Hazard " * f " " ' J it terms of reference appended Study Team `A' was formed and was assigned the tasks as appear in hereafter. Th= Chairmanship of his Study Team as entrusted m me and mental agencies, Industry and the Asbestos In cte[1 'w r|, ,]1C health problems of asbestos The Team was conscious of the absence of suitable cpidemio'osica. " " 'w oX asbestos related problems. Sufficient expertise an manpower . not secm to be available to places and timely and accurate diagnosis of asbestos-re a e meet ,h . repurremen.s in the country. Exchange of between the Government of the agencies and the industry aiongwith a c o n s i d e r . . TM ^ rX tory bodies in the developed countries, where e do" on his problem, heiped the , , p or achieving this, we have Study Team to identify (UK) reports, NIOSH (USA) reports and utilised publications by the ILO, Health & Satety lxccuu v i published articles by eminent scientists in the field. I hope that tins report wii, be helpfu, in management and reasonable protection of employees at potent,al nsk iro P asbestos dust at their workplaces; - ' , * i:,,P with asbestos- a substance that is going to be with us tor We believe that we have to learn to beneficially use other materials of toxic nature a longtime to come. In so doing,we.mig a s , same time, containing their hazards while deriving social benefits accruing from their use, adequately. The co-operation and , " h lk . c c*nrlv Team made it possible lor them. I would particular,, like to hunt such a competent team of experts. " m,i` ,,,,s oppom,m,y ,o 27th June 1985. Sd. (Dr. B.B. CHATTERJLfi' CHAIRMAN OF STUDY TEAM `A'. 9 MNAL REPORT OF THE STUDY TEAM `A' FORMED UNDER THE AEGIS o r THE COMMITTEE " TO STUDY THE HEALTH HAZARDS IN ASBESTOS INDUSTRY", CONSTITUTED BY THE DGTD PANEL ON ASBESTOS PRODUCTS INDUSTRY. Ternis of Reference ! 'Jhc terms of reference assigned to the Study Team `A' were to : Study health problems associated with inhalation of asbestos fibre dust at workplace or in the general environment, covering all medical aspects including medical `surveillance and diagnostic criteria. In case the Team felt that it was not in a position to study in detail '.i,e problem of general environment, it could prepare a n `approach paper', identifying areas of study by other agencies, giving recommendations thereof. ip! Cover 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 compensation and the policy of nationalised insurance companies regarding insurance cover or temporary and permanent disablement arising from exposure to asbestos dust. f Under the second term of reference, the Team considered that the following subjects were in the purview of the Study Team `B' : iai The agency for deciding compensation. if ) `The level of compensation. tet Policy of the nationalised insurance companies 'regarding insurance cover for disablement arising from occupational exposure to asbestos dust. Thus, the Study T eam `A' decided that it may make recommendations only on the following aspects under the second term of reference : - Composition of the panel to decide the eligibility for compensation. Criteria lor diagnosis of occupational asbestos-related diseases for the purpose of com pensation. fcam W and its Action Plan : U.c Study Team `A', comprised as under, was constituted by the Committee "To study Health ii.-.rards in Asbestos Industry" , during its first meeting held on 25th February, 1984, in the Depart- in of Environment, Bikaner House, New Delhi : i.i' Dr.B.B. Chatterjec Dr-G G- Dava>' o.i Dr.\ .1*. Gupta Dr-h-K- Davc - !); G R I'andey !! 'dr N. Vcnkaturanuin ,/ Mr J f Amin s . ' Mr \ . {attabhi Dr S P. Yivek Chandra Rno Bne D.B. Kapoor Chairman Member Member Member Member Member Member Member Member Member 10 . ,,. 311 1985. During these and abroad. which were m a posit asbestos , review an tech*iCal rnm m ittee on Asbestos constituted by ExeCU'f thc use of exposures to asbestos, papers pu literature published by :r ,:::r esto^jndH ^lil1 _ . . . limited in commercial use to Asbestos, a generic term ^ ^ y^ U S t e ! X i l d e and mixtures thereof, actinolite, amosite, anthop 3 > rrocidolite to a much lesser extent. -- 's 1. - " TO,i,e,; S C c s l r ( d a p M . mined only m Anc tra , sbestos in over 3000 products, the . nn the subject mentions about the usage o ` While literature tQ hoW many products are , manufactured in India. Most ^ whereas industrial Stud, Ira n , has * ,, asbestos cement Products and , ngs/e,,,tch facings S S a S : t i : ; = " = = " - ...-....- ........ jointings etc. as a form of pneumoconiosis turned ,,ted health issue was first identified in the U- _ relatcd t0 asbestos. Mesothelioma i Asb-stos"re*ate^ ,,no identified as an occupational asbestosis, then lung cancer t0 exposure to asbestos dust since ^ ** n wab then found that has been shown to e^ a j h, problem was limited to only ac one building formed the W S 5 2 ZS3 2 ^ , enraved asbestos insulation. insulating the buildings, using sprayed . ^ i rr huilding constiuction. lbl Triubie tusuiatton pane - ^ ^ ^ ,,,c *~ imgl.......... sed some 10 densuy ESSST* - S" h f" 'S " " d 10 h t p a s , tesnited u, P ^ g e d and ustud, 9 T,,ere ,s ,,,= * * . heavy asbestos dust exposures 10 ^ T " ''' " ^ d ,|,e level of precautions taken. " "" choice adopted lor p r o c - m . 0 , ..b u t ^ ^ ^ ^ ,, - A t t a l o s s penera.le nsns about the long latent perio v -r 15 t o ''O years & Mesothelioma 10. There is a conscns cx u[e to manliest; Lung Cancer ove uriS wuh eonlidenee taking over 10 years _ |lenomc,,on makes it difficult to re a results of conditions " 3 : ' r e y l l e t r of ihe diseases. The diseases seen today at prevalem m the pre-rogniatton eta. _______________ _____ ____________ -___ \ . jT jpijorB tdL T T tt^ 17' 2'"' trma II- Due'to the same reasons, it is also not possible to accurately predict the level of these diseases in the years to come when the effects of regulated asbestos usage will be known. However, some statistical predictions indicate that controlled use of asbestos should not give rise to any unreasona ble risk. Based on evaluation of J.C. McDonalds' Study of miners, exposure of 1 f/cc for 50 years should not cause any detectable Asbestosis and the risk of lung cancer is expected to be equivalent to smoking 3 cigarettes per month.** 12 1lie necessary precautions that have already been taken in the Western countries have virtually eliminated gross Asbestosis that led to early deaths in the past. For example, no deaths from Asbestosis have been observed in the men and women who have been studied m an asbestos textile ;.u!<>rv m Rochdale (UK) who were first employed after 1950*** A 1: is also to be noted that the latest scientific thinking favours controlled use of all inorganic l.brous materials, not just asbestos. This precaution is necessitated by the fact that several librous inorganic substances have also proved to be carcinogenic in experimental animals. These have not been sufficiently studied, nor have they been, in some cases, in use long enough to evaluate their epidemiological long-term effects. 1-t 1here are countries that arc formulating regulations to cover all fibrous materials usage. In this vontext, the ILO has prepared a general Code of Practice--"Occupational exposure to airborne substances harmful to health" ; 1980 (ISBN-92-2-102442-3). Indian Studies 15 On!\ some cross sectional studies of certain factories in India have been carried out, which are exploratory in nature. They served the purpose of bringing awareness in the industry and persua ding all concerned to take effective measures. We have no national data base on which to make an assessment of the impact of asbestos related problems. In the same way, we cannot, at this time, iffcidc the exposure limits related to our settings. Under these circumstances, it is prudent to accept the lessons drawn fiom extensive work that has been done in the developed counlrics and adopt the regulations they have formulated which will perhaps result in more than adequate protection. Limitations of the Present State-of-Art - U-. The StuJ> Team recognises the fact that the dust measurement by Membrane Filter Technique MF'D .r,J phase contrast microscopy represent the best current statc-of-art that can be routinely -..wd by the industry. A i :.er,, is no pathognomic leature specific for asbestos related diseases. -...s ;o be based essentially on occupational history of asbestos exposure. Ccmral Fatironrucnt An individual diagnosis 1 7 ho inclusion of the problem of the presence of asbestos in the general environment in the terms i reference was discussed by the members of the Study Team `A '. A Asbestos is ubiquitous and is found in the water, soil and air due to natural geographical erosions. Ii.fftrstri.il activity & technical use have added to these levels significantly, more so near the nmes, manufacturing sites and the waste dumps. ' McDonald J.C. and Liddel, F.D.K.--"Mortality in Canadian miners and millers exposed to ehrysotile" - Final Report of the Advisory Committee (UK), Vol. II. Para 202, `age 40. * Report by Richard Doll & Julian Peto to Health & Safety Commission, U.K.---"AsbestosEffects on health of exposures to asbestos" (Page 31, Para 2). 2, ~ 12 ^ ^ s J h Afnca, .here is no ev.dence of similar probl.nss In h e re ,n the world. 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 been conducted ' in the developed countries and been attended with negative results. ,, Further the approaches for quantifying population exposures to asbestos from the general environment and relating them to diseases amongst the members of the population are so d,flic 1 that the Study 1 earn members felt that they were not equipped to make any pronounesm e^ o. u , t u was aiSo noted that there has been no indigenous experience on studies of thi, natu.c. The Study Team `A', therefore, recommends that the problems of asbestos m the ambient environI J Z s v S l I d l e d by a team of scientists under the guidance of the Department of Environ ment itself Thisytcam should also include in its field of study the health proolems relating to othu T u y ocm n non.asbestos fibrous minerals, such as, the zeolites, the abundance ot eertam varieties^of^hich^in the soil has been reported to have 8m n rise .0 mcSo,hel,al , - o a . . the population, heretofore thought to be specifically associated with asbestos. Criteria for Diagnosis 24. Asbcstosis ,, Hmmotorised bv diffuse fibrosis of lung parenchyma, as. " ^ ^ non-mahgnant disease. It is often associated with fibrosis ot pleura. The fibios.s is m e ^ rsio c and the process of fibrosis may or may not progress even after exposure has ceased. Asbcstosis is a dose dependent disease. The time between first occupational exposure to asbestos dust and establishing diagnosis of Asbestosis is usually above 10 yeais. 24.1 Criteria for Dignosis 24.1.1 Exposure History There should be an evidence of substantial occupational exposure to asbestos dust. 24.1.2 Clinical Features Both signs and symptoms of Asbestosis are those of diffuse interst.tial pulmonary fibrosis, and hence these are not specific diagnostic features. 24.1.2.1 Symptom 24.1.2.1.1. Breathlessness Progressive breathlessness is the main but a non-spec.lie symptom of Asbestosis. Initially, breathlessness occurs on exertion. As breathlessness is observed in various systemic disorders, all possible causes must by excluded before a provisional diagnosis of Asbestosis is made. nps of nee ; in ,, in era! arly ions ictcci leral 3cult 1 the ture. ironironother ;rtain i the ma, as ctious, crsible re to- monary .-specific is occurs systemic uefore a 13 24.1.2.1.2 Dry cough & chest pain. 24.1.2.2 Signs. Again, these symptoms are non-specific, infrequent and are likely to occur late in the course of the disease. Hence, these symptoms are of little diagnostic 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 precedes 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. 24 1.3 Radiological Features. -74.1.3.1 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. 24 1.3.2 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 castophrenic angles, taken in deep inspiration, so that diaphragm lies below the fifth rib anteriorly and the tenth rib posteriorly. 24.1 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 1.5mm. `t' type shadows--width over 1.5mm and under 3 mm. *u' type shadows--width over 3mm and upto 10mm. 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 24 1.3 4 ` may be obscured. Pleural changes like pleural plagues or transient pleural effusion or pleural thickening are usually the radiological indicators of asbestos exposure but not of the disease. These changes need not be associated with parenchymal fibrosis. More often these chanties arc bilateral. 24.1-3-5 Other causes of similar radiological changes must be carefully excluded prior to making "" the diagnosis of Asbestosis. This is more important in the early stages of the disease when the radiological changes are slight. ^ ^4 136 Where possible, comparison of the most recent chest x-ray film with earlier films of good quality is highly desirable. 4 Lung F u n c tio n jV b n ^ ,, a l l , exposed to Asbestos. 14 restrictive lung disease. However, are"0,edi"smto ^ ^ FEVr/FVC * ' f m tel m -m -' of years is of much greater predicted values. pte. erap,o,ment or p-- ^ ,o " SE' nd" d function % ** allowance should be made for ag . - eff" ls ot ^ ^ ^ not ^ ^ " rictrye P - * eons,stent * " ^ <`" ''0S'S 04 1 4 2 While a restri ,,,,es like, 24' 1-4' Z to this disease. , restrictive lung diseases, 24.1.4.3 More * 1 ^ measurement o helpfui as further evidence, bu * m etcltsurvedlance^of asbestos exposed workers. * e r0UtinC 2 4 t 5 flitter Invest'?,11011* inon-essen_ " 24.U.1 tSSSSSU ^ . (asbestos) bod,es rn the sputum is o n l , TM - d e ,, c e o 24.1.52 Biopsy. curable ung disorder 01 reason. 24.1 . D iasnM ticC attgm SilH U ^ M bcstosis are as given below : 24.1.6.1 The mam diagnos . for at ,cast 10 years, 1LO U>) History of significant P ihbM ai bbr0,|s (category I/O or lb) Radiological features c on Pnellmocon,os,s). 24,, 2 of resrncnve W " "" I ; : I h l u g e s consistent with 'as, " " (d' 5 - . d four enreria wouid sugges, " Asbesrosis V , u the above mentioned tou would The P - e n c e of ail .be ^ ^ ^ above. alongwirh edher (0 * " T u'S" `Probable AsbestosisT ,, g . glvmg rise to similar rmbo- cTT c : ; , t d . v s Med. - 5i:;a; ; : r ; ; : i o r , -- r * SK )ai" s . ~ 2-5.1.7 Conclusion, 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 . of the above criteria. Incorrect diagnosis may result in unfounded socio-economic and psychological damages. Moreover, it may result in treatable diseases remaining unattended. Lung Cancer. 25.1 Lung cancer attributable to asbestos does not generally occur untill several years after the initial exposure, similar to other environmental carcinogens. 2f,2 Epidemiological studies have shown that the risk of lung cancer is greater at higher levels of asbestos exposure. Even so, the non-smoking asbestos workers are at less risk of contracting lung cancer than cigarette smokers in the general population. 25 3 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 may reduce the level of risk to even to those of the general population of same socio economic level. ..'.4 There are no specific features by which an individual case of lung cancer can be attributed solely 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 of cancer, even in the absence of symptoms and signs, in a proportion of cases. 25.6 Latent 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-- 25.7.1 there is a clear and adequate history of atleast 10 years continuous occupational exposure to asbestos or there is an adequate history of asbestos exposure of atleast 10 years back and 25.7.2 it is found in the presence of asbestosis or bilateral pleural thickening. Mesothelioma. 2t\ 1 Oithise malignant mesothelioma of pleura or peritoneum is a rapidly progressive fatal disease. In the general population it is rare but its prevalence in asbestos exposed workers is recorded to be more frequent. 2' 2 Latent period for mesothelioma is generally over 30 years from first occupational exposure to asbestos. ** further follow-up study of workers from an asbestos cement factory" by H.F. Thomas Et .-.I ; British Jour, of Ind. Med. 1982 ; 39 : 273-276. Mortality of workers manufacturing friction materials using asbestos" by G. Berry & M L N ' iB-ausc--British Jour, of Ind. Med. 1983 ; 40 : 1-7. " -loSucnec of do/e and fibre type on respiratory malignancy--risk in asbestos cement cunufcaurm g" by Hans Weill Et al; American Rev. of Resp. Disease; 120 (2) : 345-354. Avy, 1979. 16 sigm- s n s s . s - r r ^ n - -- * * " " 26 5 Radiological features P .,,.hellom a has varied bistolo- " 5 pleural thicbenmg- ,, aut,,psy. Bu. agam. ra<=sotl,eliom 26.6 Diagnosis can < 6,cal features au B g`r P . deal of expertise to ' d" *` '' been deHnitel,' 26.7 Fmibesroouthselizoemolaiteins hUum* an . @@. Thaenreimisalas-ltihsetsoei aPre . ,o cause Mesothelioma >n eager ^ causation of malignant and probable agents Unown 26.7.1 _ Glass fibres ^ __ Aluminium Oxide -- Attapulgile _ Silicon carbide __ potassium titan ate __ Wollastonite 26.7.2 Probable Pleural tuberculosis - f0,ind in an asbestos * the disease Wh" r " e ; ; o s m e for .be p u l s e s or eompens.1 P 26.8 caused by asD _ condition is m e t. a '. ,e histor, of a.l.eas.t',5e gears mconntinvrous occupational 26.8.1 There is a ciear and adequate history exposure to asbestos T f 15-gears between hrsieapos-ue to ashes,os aad There ,, a minimum interval of 1 26.8.2 appearanee of Mesothelioma. 27. General - 4 , . n u v e , . - should be hep! asbestos fibres above the Ac 10 India, we min ream reeom -- ^ _________ __ set 00..5500 ff/lmmllaass tthhee AAccttiioonnLLeevveeLl.---------- ^ T T M -T---c----a- -i-d--i-i--e r I-WW' *1-------- * ' " Asbestos-the control #m# f ' " ^ " p m a ^ O T - P a g e 16) Sa; Health & Safety Commission. UK. PAR'S * l * < A" " N>' ..E,,vironmen,al mesotheboma in Tu V - (('(o' 3,0:423-432 .,0cclipMi,,nal Exposure to An ' *** The 1LO Code Level as under : workin environment Health" , 1980, defines Actio harmful substances in the ' ^ Umlts und n a level of exposure of workers o . It js distinctly be ow application of all . ^ determined b , the consequently exposures W e tit. preventive measures ___ the action level, m do not *> ^ ^ of a medical nature lcve, ,,,11 gene.. = f for exposures ,,,,low half ol the 17 '.3 I'rc-cmploymc, mod,'cl examination. 101 1" 'od`c medical examination. <cj `^iciiicaJ examination at cessm,TM r , <1 Medina, Records. " r TM'>'oyme,,,. (c) ilealth education. ^ ^ i p i r o nt Medical Examinnfinn A mcJicn! examination , .0a place or worit invoicing exTM " 2 ^ * * "P" i ^jjeeiivcs. * P*>r lo assignment 2H`U T deicrrnine any condition which wnnM , sure to asbestos; examp,es arc: the predicted values (FVC and F P V o /u * ^ dM-ormaiitysdonid be p t l S t t ! ' hmarked,yredaced ' .T T ^ o n a l expo lung funettn ? as -stos. rite worker will, chronic bronchitis aal " ' T ' ' " 8 potm ,tal exposure to impairment, gross chest ,,11 abnorm alityac L '"'" " " '" `sis, gross cardt be employed in a p,ace ,,-here there , ` 7 tnbereniosis should ,, 7 below ls yetirs oh age shonid no, be cm oy" " f ' *" ^ 1.2 To educate and advice wnrlr^ro u * , P sd hr Sl)eh workplaces. = ,, , , * 1 estaohsh baseline medical records for f th 2.2 S U a c t u r ^ Examination" ^ SUrVe',lanCe- The pre-assignment medical p.,.., ~~ ~ ~ then, m exposure to asbsetos ^ W0* * ^cly to involve r ' :r :r i;:r r* *.. of <.s.,espee,: ,,y asbestos and Z Z " % * " ~ worter " * " * - - e r a - a n te r io r eh J , < _ most recent 1LC gUide-hnes ^ " - -- -- - stndy * " rdio-respiratory ^ be obtained and interpreted ^ J = L ^ I I : in addiiion, iung f , t a r i;~ -- - . , " C nd (FEV`>- capacity (KVC) . measurements cutive years to establish a inorc^rerihP ^ fkould ba done every year for f t 1S obsvcd ia these tests, a re p iu tes 5 basc,inc data. In L I T \ fm t two consc- j j j f i j c -Medical Examination. S U ^ d ne after six months of fe ^ o n d ^ ^ 00 Objectives. >2.1.1 To detect the earliest signs and symptoms of a H : 2 To detect the earliest signs and s * , s -_prrersci n"i! a! s/il1""1i'1l"ar1 P ic tu re d i n t L i t f a T S diseases i^inlncessss wwhhiicchh ccmould `" 4U r3 ;"'"ii.Stt? 18 TO continue ,o * * * . * ascertain (hat appropriate p,event,ve measures are betng ta St "* 70 ? structure of Periodic M e d ic a ^ x a minations- .............. Periodic medical examination of persons potentially exposed to asbestos dust should me u e . 29 2 1 a rclevcnt, brief medical and occupational history including smoking a t , 29.2.2 job details that could allow reconstruction of exposure pro es 29.2.3 a clinical examination, with an emphasis n ^ ^ ^ l i n e d and interpreted using the 29-2 -4 to be compared withthose of prev,ous chest radiographs; . nrM- ... meas,, t ,, F V r and FEV, for comparison with previous meas 29.2.5 spirometry to obtain a representative FVC and f i ured values; particularly in workers with signs 29 2 6 additional tests as necessary for diagnostic purposes, particular y and symptoms suggestive of asbestos-related d.seas . 29.3 M edigL ^ g S tS aS g .- shoul(ltovc his firs, periodic medical 29.3.1 Every worker, irrespective of h.s " T" '_emp,oy'ment medical examination. Thereafter, examination done, five years P j cl js m0re than Action 29.3.2 The 1L0 Code of Pract , P below the Action Level do no.t...n..e..c..e..s..s..i.-. 29.3.3 Periodic medical examinations may d| of the previous medical examination. "-S p suspected case of asbestos-related disease. 30. Interpretation. 30 1 Radiographic Evaluation. ' 30 U Radiographic evaiuation of fhc worker exposed the 'T I.0 1980 International classification of radiographs oi the pnen subsequent revision thereof. ^ 30 1 2 The occupational physician may ask oblique, in selected cases, for further information. of ,,,c chest "= 2 Hkc, ,atcral or 30.2 P jilm o n a r y ^ ^ volume-flow or volume-time ,. r Vr FFV a device which provides a tracing o .. L0" 1 , l 7 . h e e n iire ^ c e d expiration ,s recommended. The tracing shouid be stored * aval,.,- blc f,,r recall. 1|ie ^ ^ be ,,roperiy demonstrated and a .M r * impairment on spirometry. rsxxzzsz srsz ^ or ^ a l o r y sythPtoms ot * , * . 3! Medical Examination at Cessation of Employment 31.1 Upon the cessation of employment, a full medical evaluation including review of all investi . cations done during periodic medical examinations should be performed. 31.2 The employer should arrange for the medical examination of the employee within 30 days of termination of employment. 31.3 At this medical examination, if the worker is suspected to have any abnormalities related to asbestos, 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 time. ' 2, Medical Records 32 1 Medical records should be maintained in accordance with good medical practice, -ecognising the long latent period for asbestos related diseases. 32 2 Medical records should be maintained/stored for a period of 10 years following the termina tion of employment, or for 40 years after first day of employment, whichever is later. : 2 3 Medical records should include the details of pre-employment examination, the periodic medical examinations, and the medical examinations conducted at other time, if any. 32 4 As part of overall medical record, records should also be maintained of the individual employee's occupational exposure profile to asbestos, specific work practices and preventive measures prescribed, if any. %} Health Educatioo/Appraisal of Health Hazards*3 *<3 ! tvery employer should ensure that all workers(employees) on employment and at periodic intervals should get education and training in regard to sources of asbestos dust exposure, potential health effects, risk associated with asbestos dust exposure and smoking and, methods of prevention. 33 2 'file employer must apprise the employees of adverse synergistic effect of smoking cigarettes, beedies, cigars and occupational exposure to asbestos. It is suggested that this information be made available to all workers exposed to any level of airborne asbestos particulates. M Medical Panels One of the points amongst the terms of reference assigned to this Study Team was to recommend on the formation of medical panels and their composition, for providing final d.,ignoos m cases of dispute or doubt. The Study Team considered that : in \iew of the complexity surrounding the diagnosis of Asbestosis and other asbestosrelated diseases, separate medical panels should be created for adjudicating on all cases of such ' diseases and entitlements for compensation; 3-t 2 panels should be created in different regions, keeping in view the geographical density of asbestos based industries. This will be conducive to early disposal of disputed cases; y.* j ..uch panels could be created under suitable enabling provisions of the Factories or . the Workmens' Compensation Acts and should function inaddition to the Pneumoconiosis Boards/Panels under the Indian Mines & the ESI Acts; 34.4 such panels should also function as referal bodies in cases of asbestos related diseases for workers not covered by the Indian Mines Act or the ESI Act; 20 - s s s r = ; r f `^ H r 5 S S S S radiolosv or a physician who has been especially traineu m m . . . ... preferably"those related to asbestos das. or an experienced occupational health Dtosieian if available. Otherwise, a panel would have two chest phystaans and one radiologist as members, with the senior chest physician as the pres.d.ng o cer. 34.6 in view of dearth of medical expertise in diagnosing Asbestos!. a n d 4 t " TM d ' diseases, it is desirable that the members of the constituted panels ^ e e.a<:oiuraged visit the recognised institutions and panels abroad to obtain specia lze r ini experience in this field; 347 such panels may refer to each other incases of doubt but their decision!i would be ,,a! and no, justiciable or referable to panels of seemmgl, mcreasmg tmportance. 34 8 opinions of national or foreign experts, if obtained m a particular case or cases, should be made available to the appropriate panel for its consideration. 21 FINAL REPORT OF THE STUDY TEAM IT FORMED UNDER THE AEGIS OF THE COMMITTEE "TO STUDY THE HEALTH HAZARDS IN ASBESTOS INDUSTRY" CONSTITUTED BY THE DGTD PANEL ON ASBESTOS PRODUCTS INDUSTRY PREFACE In pursuance of the decision taken by the DGTD Panel on Asbestos Products Industry to con stitute a Committee to " study the health hazards in asbestos industry" , a study team designated as Study Team `IT under the aegis of this Committee was constituted. The study Team `B' was assigned the task of examining the adequacy or otherwise of the existing legislative provisions for protecting <ccupationally exposed workers from the risk of asbestos induced maladies. t, The Chairmanship of the Study Team `B' was entrusted to me by the Committee and I had the p;ss)legc of heading the team of 10 eminent expert members who were specially drawn from the uosernment regulatory agencies responsible for the Factories, Mines Safety, Environment, the Industry a~4 the Asbestos Information Centre in order to provide a broad spectrum of experience concerning the subject. The expertise of the members has indeed been of immense value in the study and critical of this complex subject. I n.;ih tu place on record the ready and whole-hearted co-operation that the Team received at 3! places it visited, including asbestos mines and the factories. The visits afforded the opportunity for a free exchange of ideas with the producers of asbestos fibre and asbestos-based products both in the Urge as we!! as the small scale sectors. I, on behalf of my Team members and myself would like to espies* my grateful thanks to the management of the mines and various industries and their personnel 'rh1. helped us to compile the factual data and relevant information on the status of protective -siaujrc'. that had been adopted by them. I wonid also like to gratefully acknowledge the active advice and guidance that I received from ns scam members who showed great commitment and dedication to the task and did not hesitate to readily give their valued time for the series of meetings and study visits to distant and far flung places Silr.Ow.Ebpah in the Andhra Pradesh, Udaipur region in Rajasthan, Hyderabad and Bombay. i would finally like to thank Mr. D.K. Biswas for providing me this opportunity to lead this competent team of experts in their respective fields connected with the task assigned to me, as the i man. Hyderabad, Mm 23, 1985 Sd. (Dr. G.G. DAVAY) Chairman of Study Team `B' 22 FINAL REPORT OF THE STUDY TEAM `B' FORMED UNDER TIIE AEGIS OF THE COMMITTEE "TO STUDY THE HEALTH'HAZARDS IN ASBESTOS INDUSTRY" CONSTITUTED BY THE DGTD ObM. PANEL ON ASBESTOS PRODUCTS INDUSTRY Terms of Reference 1. 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 o 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. Under 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 Govern ment of India, the Mines Act and the Draft National Regulations formulated by the Asbestos Informa tion Centre (AIC). ' 3. Under the seeond term of reference, the Team was asked to include m its study the agency foi 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 Health Hazards in Asbestos Industry" during its First Meeting held on 25th February, 1984 in the Department of Environment, Bikaner House, New D elhi: (a) Dr. G.G. Davay (b) Dr. V.P. Gupta (c) Dr. G.K. Pandey id) Mr. G.S. Ichhpurani, (e) Mr. B.K. Sharan (f) Mr. N. Venkataraman (g) Mr. J.B. Amin (h) Mr. V. Pattabhi (i) Brig. D.B. Kapoor, (j) Dr. P.K. Sishodiya Chairman Member Member Member Member Member Member Member Member Member '* 1 r i a J I 5. The first Meeting of the Study Team `B' was held on 1st September, 1984 in the Factory Inspecto rate Office at Bombay. During this meeting, it was decided that indepth Knowledge of the working conditions in various types of asbestos based industries, asbestos mines and docks would be essent.al to enable the Team to make effective and practical recommendations. It was thus decided that the 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 pitheads and asbestos product manufacturing units at Hyderabad, Bombay and Udaipur region. The existmg provisions under the Factories Act, Schedule XIV on asbestos and Model Rule 123A were reviewed. 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 the Draft National Regulations, formulated by the AIC and the ILO Code of Practice were stud ec. The Study Team also took up for review the modified provisions of the Workmen's Compensation Act, ESI 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 revicws/visits were fully utilised in making its observations and drawing up its recommendations. 23 6 The report on the visits of the Study Team to the asbestos mines and pithead milium plants is given at Appendices A' & `A l.' Teams' report on its visits to the asbestos products manu facturing units is given at Appendix `B'. Obsenations 7. General r otherwise he risk of jy in depth is workers. ,.\ - The visit to various 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 ob served at the various sites visited is attributable to two important reasons. lodel Rules re Governis Informa- agency for nationalised bestos dust. tudy Health Department irman iber ' rber iber iber iber fiber 8., nber ' nber liber ory inspecto- 1 the working 1 be essential : ided that the , /, visits were : ;s at pitheads The existing i ire reviewed. ` ; Ocupaiional ' U.K. and t he, were studied, ?icnsation Act, ' dated occupa-f sits were fully r1 7.2 The first point of importance is the process 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 was part mechanised 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 asbes tos 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 table 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 equip ment be considered a permanent substitute to effective preventive engineering control methods. It can at best be a contingency measure, to reduce personal exposures. 7A The second point of importance is the level of implementation of the in-house hygienic standards. There are units where the Team noticed adherence to these standards at one end and a total neglect of the same at the other end. One reason for the latter is the ignorance and lack of knowledge about the hazards and implications in the handling and ' use of asbestos. Legislative Regulations for Asbestos*18 # I Factories Act & Rules is,LI The existing definition of the word "asbestos" in the revised Schedule XIV was examined and the Committee found it adequate, as mentioned below : "Asbestos" means any fibrous silicate mineral and any admixture containing actinoiite amosite, anthophylite, chrysotile, crocidolite, tremolite or any mixture thereof, whether crude, crushed or opened." 8.1.2 The provisions under " Application of Rules" and " Method of Monitoring" given in Schedule XIV are considered adequate. However, some minor changes are required. b L3 The committee examined the existing Model Rule I23A 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 Revised Model Rule 123A. h.1.4 Schedule XIV on asbestos and the Model Rule 123A specifying the permissible limit of exposure have not yet been adopted by many of the States. 8 S.5 The method of sampling and estimation of 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:. level measurements. 24 . , j in thp Model Rules should be further explained to . " * ,.6 An e x p o s e lev,, of TWA re c o ^ e n a e d n ,,corporate these details in .he is a comp]cx tc c h iw ic 8.1.7 The Team considers that the ^ p g ^ j^ ^ ^ d e v d o p e li with the assistance of well liable to wide variations unless en g P established asbestos dust counting laborator.es. ti 8 ! 8 There should be a procedure and programme to standardise the pract.ca as 8.1.8 oinfeitchMe fiioburo. us dustrto reduce inter-llaabDoorraatiouriyy variations. * , 9 The Team is of .he view that no sampling " d "X 's t ' U r d c o n m ^ b v Filter Technique (MFT) be used as n o - c e p * . foTM S,economica, ,, ,, h o d ,,nicer, different methods and M FT is by far the most pract.ca sally accepted for this purpose. ^ ^ ^ for a,, types of asbestos dust. , 8.1.10 The revised Schedule XIV now speci J The study Team is aware ot the trend m the adJ countries to further lower the pu of thc present ter^o-econom .c missible limit. . However, after car"ful d bearing in mind that several countries, feasibility in India to implement the standard that the present rccom- Japan, stil, consider 2 f,oc as lbh point of time. ,,edeh perm,ss,We level of 2f/cc ,s P 8 , 11 f, is also considered that Shot, Time Cedmg Value of lOf/cc on minutc sampling per.od b' 8'U 2 " : " , . bv ,his stl,dy Team is .,,eluded as Append,VCd I, * ^ " S s h i d s o o n h r m g u. a standard for the measutemen, . f J o T d u s ts w h ic h should then be uniformly adopted. Small Sc;ale Iindustry 8. 2.1 ;ne S l p e r e ,0 come ,0 gnps - lhe ptohiem and to tafie snitaWe eon,to, measures. ^ ^ lll; 8.2.2 As these units are already estabUshcd and are these units be assisted to implement t e reg helped to establish manufacture, y way o p ^ ^ ^ ^ way an SSL unit incentives both financial and technics f he use of asbestos and other sue - " unitsrequ11' ^ control of dust, personal samp ing determines classification for Small Sc. counted for the capital investment clause which determ SCCt0r' - En j i n e e ^ l directed to po . . ,, 0 | c or other concerned agency should. f `r the'SUppression/control of asbestos dust and to h , ;ns^aj\ appropriate equipment, the Small : The Small Scale Industry should be encouraged to p - dust counting centre. also a health C t t s " h of . compe,e,,, qualified person. ""J6 , ,, : Employees in this industry should be made aware of the need tor stmt plementatTon of ,he asbestos regulations and the beal.fi haords .,, a 9 occupational exposure to asbestos. 25 explained to , ^ $ 3 tails ^ the x technique ' nee of well s of counting Mines Act; Regulations & Rules Thereunder. $-3.1 During visit to the underground mines, fibrous deposits were noticed on the roof, walls and floor which were dry and were not kept wet in the travelling and haulage roadways. S.3.2 Relevant regulations of MMR 1961 do not provide for environmental survey of open cast mines and underground mines less than 50 metre depth. These also do not contain appro priate 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. e Membrane countings by ;thod univer- asbestos dust. , iwer the per- , hno-economic ral countries, resent recom- $.3,3 The open cast mines in Udaipur were mining the ore deposits manually without wetting. It ib necessary to monitor these workplacesi, to approve the present method of working. 8.3.4 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. 8.3.5 H W3S observed that the processing is carried out using small machines without total/partial dust control measures, resulting in unsatisfactory dust level exposures to the workers. St.3.6 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. impling period. tdix`C.' It is, easurement of <i S J," The Team suggests that the milling operation be pooled to enable installation of modern milling plant with complete dust control systems & provision for safe disposal of asbestos waste & tailings. Compliance of Regulations. tat they neither e to grips with :commends that an SSI unit is and technical, and other suet ts require assis-i needed for tht , >ry shoul d not b n for Small Scat rency should t dust and to he! ncouraged to po a health surveif need for strict it might arise due ' 9.1 It is observed that State regulatory agencies entrusted with the task of implementing the controls on asbestos and other toxic substances are presently not adequately equipped with proper equipment and other resources, including trained man-power. These facilities are . essential to ensure adequate compliance to protect the health and safety of the workers. 9.2 The industry should periodically monitor dust levels to ensure the effectiveness of the engineering controls. <1 The Team received the record of monitoring from several industries. Whichever of the t-d-sir) units that has not yet implemented the monitoring scheme is advised to do so w.Umut any further loss of time. 9,4 The Team requests the Government to be liberal in allowing importation of the latest equip ment required for the purpose of monitoring dust levels and medical surveillance of emplo%CC* 4 < Some of the small scale manufacturing units and pithead processing units had emyloyed children and adolescents who were being exposed to heavy dust exposures. The Team con siders that this practice be prohibited. i,lc*oang of New Manufacturing Units. lo.i During the visit to various factories the Team observed that several equipment and plant now being used are not by design meant to process asbestos fibres/products but have been adopted for the purpose in an adhoc manner by the management. It is felt that equipment and plant used for this purpose are manufactured scientifically, taking into consideration the need to keep the air-borne asbestos dust within the permitted exposure levels, whether it is within the factory or in the stacks, when let out into atmosphere. While the Government now requires specific environmental pollution control measures before any new licence is granted such specific provision to control workplace exposures is not existing. Notwithstanding 26 . , ,, , a *ru\ Rules it is recommended that the appro- the provisions existing in the factories nr0visions are made before licensing priate author!,, should satisfy itself .ha, adequate p ,ialurc 10 avoid further units. The provisions should be speafio and not genet, subjective decision making and to ensure uniformity. ,0.2 The Team has also been informed of < hence, may not come IheJ UTM ^ ations and p aceS be brought under Central/Sta.e T u ir; " r j 1* enab,inPg provisions under the main AC. 11. Packaging & Handling of Asbestos Fibre. 11.1 The Team has taken note that r $rules^re not Applicable, prominent among - *- . . . 11.2 The Team observed that fibre p r o d u t a e i ' s h o u l d bags. Such a pracllce ^ ** U be packed securely - <* p , a r TM ; " d e fining is preferred. Use of hooks shon.d be stri.,1, avoided and 15 such an instruction should be printed on the bag. 1 1 .3 When imported, the asbestos ^ t" - L 7" raga: C o r r t h * * * -- .o urdmac, and entry the unit loads. U . , tn formulate a Code of Practice for the guidance of the asbestos 11.4 1S1 should be requested to formulate a c-ou users, both in factory and non-factory operations. 12 Medical Surveillance. The methodology to adopt medical surveillance ,s a subicc. for another stud, team h o * fmdutgs would need to be integrated with this Report. 13. General Environment. . , ,,F 13.1 The Team has not studied the emission ` factoring factories or asbestos ^rocssing^uni^^^^ finot from the asbestos product manugeneral environment. This aspect the Team considers that the' X e ^ U u t i o n S r B o a r f s l u l d look into the feasibility of bringing out standards for emission of asbestos dust into the ambient air. The Team observed that the solid waste tailings from the raw asbestos processing units was 13.2 beinjstored in the open and then, disposed off to the public, which is hazardous The Team h that a Code of Practice for the disposal of solid waste tailings be drawn by the Department of Environment/Pollution Control Board/ISI in accordance with international practices. 14 Compensation. ties in the interpretation of these provisions. 14 2 Criteria for the diagnosis of the above mentioned asbestos-related diseases need to to- specified. 27 d that the appro- . 4 before^, licensing nature s avoid ower is used and s the considered ler Central/State he factory where rominent among 14.3 in case of lung 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 alongwith asbestosis or bilateral pleural thickening asbestos is deemed to be its cause for the purpose of the compensation. 14.4 There is also a need to designate an agency with specialized training to decide the eligibility of claims for compensation from the medical angle. 14.5 The ESI Act does not make provision for compensation after the employee--ESIC relation ship has ceased to exist. The ESI Act should be ammended such that the ESIC is made liable to pay compensation, even after cessation of employee-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. ' in ordinary jute : packed securely m lining. Woven ;lly avoided and 14.6 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. 15, Substitution. lual bags should ould be standarlad and carry the :c of the asbestos i whose findings TEr Study Team noted that DGTD Panel on Asbestos Products Industry is already seized with the aspect of substitution of asbestos fibre by alternative fibrous materials based on technical consi derations provided they are less hazardous to health and offer equivalent techno-economic advanUfet in views of this, the matter was not pursued. l i Recommendations. . At. a results of the visits, deliberations and the observations made in the preceding paragraphs thi .Study Team offers the following recommendations : ' Hvl Current prescribed level of 2f/cc as specified in Model Rule 123A is considered adequate at the present lime. MFT should be used for the measurement of the air-borne asbestos fibre uust (ISO draft is available). os product manu- , ait. This aspect ' considers that the out standards for cessing units was 'dous. The Team be drawn by the dth international ' lung cancer and ! some uncertain-1 senses need to be If-2 framing of Rules according to the Schedule XIV and Model Rule 123A by the concerned States is an urgent requirement. 16 3 - 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. 6 4 Personal protective equipment should not be considered a permanent solution in place of preventive engineering control measures. At best, this should be a contingency measure. 16 5 Every process and equipment related to the milling of asbestos ore and processing of asbestos nbre should be studied tor its potential to create air-borne dust. In case any process/ equipment releases dust that cannot be controlled to the desired limits by engineering' centre methods, such process/equipment should be prohibited. it, 6 Equipment used in the processing of asbestos should carry a certificate from the manufact urer that during normal usage as recommended, the equipment will not release fibre dust levels higher than the prescribed limit. 16.7 Management and control of asbestos dust in the small scale sector of the industry need to be tackled on priority basis. Major recommendations in this regard are: 28 -- Financial : Subsidy should be given for the purchase of equipment needed for the control 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 encouraged 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. ]6_g -- 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. _ AH operations and places where asbestos fibre is used should bo brought under ti e 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 modified to biing them upto the International Standards for the control of asbestos fibre dust during mining, handling and milling of the ore. -- Where applicable, the rules under the Mines Act should be modified so as to include the relevant provisions of Schedule XIV and Model Rule 123 A made under the Factories Act so far as they relate to asbestos fibre dust control. -- Asbestosis ; lung cancer and mesothelioma when they are caused by asbestos should be notified as occupational diseases under the Mines Act. -- Specialised trained manpower and equipment are to be provided to effectively monitor the environmental exposures in mines and medical surveillance system of the mine workers. 16.10 State Pollution Control Boards should make emission standards for the control of asbestos fibre dust in the general environment. 16.11 Packing of raw asbestos fibre should be in impermeable bags and should be handled as unitised loads as far as it is practicable. Empty bags should be disposed off as per inter national practice and should not be given to the public. 1SI may be requested to bring out the Code of Practice for packing, handling, transportation and use of asbestos fibre. 16.12 -- The employees covered under the ESI Act should be eligible for compensation after cessation of ESI coverage, as is the case in Workmen's Compensation 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 compensable only when either asbestosis or bilateral pleural thickening, a concurrently present. dec! for the ould not be )n for ' 'iall be directed ; . to help the icouraged to dso a health s regulations estos. ol to be met ; be issued by : have already ;ht under the workforce or died to bring : e dust during ' 29 - I here is need to designate an agency that possesses specialised training, expertise, competence and facilities to decide the cases entitled to compensation arising out of asbestos-related diseases. -- tmployers should be required to cover their employees under general insurance in case they are not covered under the ESI Act. H in Government should be liberal in allowing the import of equipment required for the use in dust monitoring and medical surveillance. Si 14 1S1 may be requested to expedite formulation of : - Standard for the measurement of airborne fibrous dust. " Codc of Pract<ce for the packing, handling, transportation, and use of asbestos in the factory, mine and other places. Code of practice for the use of asbestos containing products. ~ Codc of Practice for diposal of asbestos waste materials, including tailings and empty bags. 14 i i Following amendments to Schedule XIV on asbestos be carried out : Thc words "following operations shall be enclosed and provided with", be added before the 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. 0 include the { the Factories ; 1 sbcstos should lively monitor m of the mine . b rol of asbestos oe handled as iff as per inter- d to bring out, fibre. : pensation after :t. ' iied and should easons it should 1 thickening ii A P P E N D IX -4A ? VISIT TO ASBESTOS MINES IN CUDDAPAH DISTRICT OF ANDHRA PRADESH 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) Small Private Mine. The Team reached .Pul,venda, at. about ,0.00 mining method and operations were exp a.ned to ,1r c ^ M / p . clludhary, Managing E l " - Mr. T v ' s Ram, Genera, Manager, A.A.C. Ltd. explained the general geology and-method of working of their mines. of which ar given subsequently'.' Only Chrysotile asbestos fibre is mined at Puhven . There are about 10 underground asbestos mines situated in Pulivendla area. The total strike is about 125 metres. General geology of the mine is ^ ^ ^ worked by Andhra belongs to the A.P.M.C. which is a tate un e i ' and a Public Sector). Other Asbestos Corporation Ltd., wn.ch is joint sector (A.P.M.C. mines belong to private mine owners. ; Method o f Work,oS. The method of working is almost the same n, al: the n i.e s. Indine. ^ 0 ' -------- " , are driven from the outcrop mtirtf. vpin is developed in a bord and pillar pattern. width of the g.llenes vanes ,e,8hto t r 3 t,r e , VresrleThe" ^ of he pillars varies from 5,5 m X6.5 n, ,0 15 m X 15 m ( I d ) The minera biooks are stopped on, by .erhaud/or breas, stopprng by on, and ,1,1. r n e t l V The dri.es are blasted in .wo rounds. The low ., half, containing the mure, is blasted in second round. The mineral obtained from the underground is btoug t l surface by direct haulages. .Toint Sector Mine--Date of visit 15.01.3_5. ft The General Manager explained the method of working. The additional information r ,, i d hy the members was furnished by Mr. G.S. Ichhpuraui After study,ng l e plans the team went down through the manway to 1st level and trave e upto no 1 1 werd'down to 4th level through 2nd dip. and emered the return ,,way through s a, crossing and reached the Sth level through companion dip. Alter studying r ;r , r to the surface through the same route. During the visit, it was o b .e .u ...at was deposited on the sides of the travelling roadway. The working environm ent, ventilation system and general surroundings! in actual working arid operations were observed by the Team members. 5*. Proce'i'iing 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 is subjected to manual sorting of the asbestos bearing rocks (ABR). The ABR is then handcombed for chipping off the asbestos bearing portion in smaller pieces ranging on an average 2.5 Cm. (1") pieces. This is collected and is known as asbestos concentrate. From the ABR, the serpentine rocks are 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 are separated which are fed to the double deck screen which has sieves of 10 and 40 mesh. The screening gives three fractions : ta) Oversize. (b) Middling. ' (c) Tailing. Tailing is the waste which generally does not contain appreciable quantity of asbestos. The oversize is recycled in the hammer mill and the middling fibre is sucked up by a cyclone and collected. Whatever solid comes from the separation of fibre in the hammer mill is again fed into the hauler. The fibre in middling is again subjected to double deck screening having mesh size of 16 to 40. Particles which are less than this mesh size are a waste, which is taken out for dumping. The fibre from the screen is again sucked up by the cyclone tiparator and the fibre is collected- All the operations which involve feeding of discharged material to the other processing machines are conducted manually. It was observed that the air from the cyclone collector i* ihrown out into the external atmosphere without passing the same through bag Alteration vyslcm. The fibre from the cyclone is collected and removed to blending area where diffe rent batches are mixed togethei. Then, the Same is packed in HDPE bag and weighed. The packing is done in 25 and 50 kg. bags. The bags are not labelled with the hazardous prope rties of asbestos and its source. Trnkrtakings Mine--Date of Visit 16.01 85.*i. v n,c Managing Director and the Manager were present during the visit. The Managing Director explained the method of working. Then the Team went underground. The various operations such as drilling, mucking, transportation, charging and blasting were arranged so that the Team could study the dust problem in various mining operations. jo The Team went down by main travelling roadway to 2nd level and through the winze N'o. 23A went down to level No. 6 and then reached the level No. 7 through the air crossing. Then through No 4 incline and winze 12A, the Team reached level 9 and inspected the following faces : --- Level 9 East face-drilling operation. -~ 11 dip of 9th level-mucking operation. ii. The charging and blasting were arranged in level No. 9. First round of blast for 12th dip was arranged. Six holes of 1.2 metres were already drilled and kept ready for charging. The 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 samples were collected from the airway. SI The Team visited the processing plant. The run of mine is handled the same way as 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 disintegrator. The ABR obtained from the-jaw crusher' as.well as the disintegrator are fed 32 rotates and the vertical two ~ -- 4 in- - : i o( IiecorticMi0, ,, 13. process the nores runners. ~ separat" ~ the solids are subjected to ano e eccentric sieves. The fibre so obtained The collected fibre after decortication are siev d ^ 14. is hep, ,n separate b a t c h e s ^ TM ,.e d t o p e t ^ . ^ fMhioni the coarser solid particles hhres and solids. The fibres " * m" 11 (he , th |eve, Thm , lbe Tcam came up,a 15. _ 11th dip of 6th level. ^ ttafo,iowinBp,aces: __ 10th incline (main dip) drilling. ' - . theTe1mretur,,.d tothesurf.ee through the same route. Af,er inspecting all operations, the Team re separated in the usual , , The Team, then, * * - X^ ^ manner to mass ;s subjected to deoorticntion whmh C IS ^ the solid'rocks. The fibre is then subjectedl.o sieuing^ P^ ^ The flb[e obtained are fed to the huller wh.ch fur,lie" ' P" d ,, HDPE bags. Various operations under,akei, - -- 17. The Team made the following observations . --- ** aIld making asbestos concentrate (a) - : r : : l g h o u , the year, including the summer. (bj The firs, double - - - - - * -ht ~ _ ...... ions wen ,,..gt hauler operations environment (visually). ' " ' " r e to rn ,he outletand out-going ah from the eye,one s,tea W The t r ^ t m g l b l t o s fibre in .be work environment. were also emitt g (d) The operation of mixing different batches o f asbestos fibit llv was also contain manna,,. ,,.ting the work envtronment. being manual,, hammered to sort ot ic, ABR having longer asbestos concentrate were superior grade asbestos : Grade 1 - More than li" Grade 2 - 3/4" to H" G rad, d - i1" to0 33//4" These were being subjected to manual J '" . I , gave off asbestos fibre in the work ovnonment. ralion oE jigging and hammt P f ) The overall observation of the Team was that the operation of hammermill, huller and cyclone operation were emitting huge quantity of dust exposing the workers and the population in the surrounding areas. w) Machinery and equipment as well as the auxiliary need to be redesigned so as to pre vent emission of asbestos dust in the environment and the,surroundings. Ill 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 en closed filter bags system and then, only the air which is not containing asbestos dust be let out into the external atmosphere. ' n) General house-keeping of the asbestos processing plants was very poor as asbestos was being handled without any regard to health hazards that it posed. Catridge type respirators provided to the workers were non-functional and unsuitable for effective 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 was seen to be provided to store the personal protective equipment. No separate room was provided with dust de-contamination equipment. Workers were keeping their clothes near the workplace. Young persons were seen employed on all operations. No cautionary placards relating to injurious effects of asbestos were displayed in the asbestos 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 mines are medically examined only once in five years. No system prevailed to monitor the work environment. 34 ANNEXURE-I TO APPENDIX `A' LIST OF STUDY TEAM `B' WHO VISITED MINES IN PULIVENDLA, CUDDAPAH DISIRICr, ANDHRA PRADESH 1. Dr. GG. Davay, 2. Dr. V.P. Gupta, 3. Mr. G.S. Ichhpurani 4. Dr. G.K. Pandey, 5. Mr. J.B. Amin, 6. Mr. V. Pattabhi 7. Brig. D.B. Kapoor 8. Dr. P.K. Sishodidia 9. Mr. M.L. Dabral, Development Officer & Member Secretary, Panel on Asbestos Praducts Industry, Directorate-General of Technical Development Udyog Bhavan, New Delhi-110 Oil APPENDIX 'A -r VISITS TO ASBESTOS MINES AND ASBESTOS PROCESSING UNITS IN RAJASTHAN I he Team Members had their first meeting at Udaipur 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 : (a) Dr. G.G. Davay lb) Mr. G.S. Ichhpurani fc) Dr. G.K. Pandey (d) Mr. J.B. Amin (c) Brig. D.B. Kapoor tf) Dr. P.K. Sishodiya tg) Mr. N. Mishra (h) Mr. R.C. Chaudhry Chairman Member Member Member Member Member Invitee Invitee Dy. Director of Mines Safety <<,) Mr. R.S. Sharma Invittee - Suptd., Geologist Dept, of Mines & Geology 2 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 and 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 Directo rate-General of Mines Safety, there were 26 asbestos mines in Ajmer District, of which 18 uere working mines. All these mines are opencast mines. The mines employ about 250 persons and produce 16,000 MT. of asbestos per annum. 4 a was decided to visit a few opencast mines in Udaipur District on 21.2.1985 and some asbestos products or processing units in Udaipur and Ajmer Districts on 22.2.1985. mt to Mines on 21.2.1985 Kirat Asbestos Mine (Taluka Jhadol) i.-c mine was being run on the sides of the hillock by opencast method. The size of the quarry was ..--'foximatcly 20 metres wide x 10 meters high. The sides consist of soft strata and were being .. orked by pick-axes. The management possesses a lease area of 299 hectares. It.- production of asbestos ore is about 2,000 tonnes per month. The sides of the quarry were >T-pl properly benched. The run of the mine ore was being collected in"Tagoras'' (M.S. Shallow >-u-h* The tagoras were carried on head and taken to a stacking place for breaking the ore. The . -c being graded into two grades, namely, No. 2 and No. 3. Grade No. 3 is very brittle and in W powdery form. The graded run of the mine is carried in the trucks to the processing unit (s). is at observed that even cutting the sides of the quarry by pick-axes raised small quantity of ,,,4, in t|ic air. Similarly, the dust was raised while filling the tagora sand dumping at the of grading as well as during loading of trucks. The workers were, thus, exposed to the asbestos V,.;, f ur grading the ore, at the mine, the run of the mines was screened manually. This also " J 4`cd thc dust to rise in the atmosphere at the working site. The average earning of a worker stated to be Rs. 9.75 per day. 36 6 Ganuir Kiopal AsbcstosMinc . . d Z Z I Z mt c 'Z T ^ Cl X " a s S tated'" 'L * . P ro , 30 metres wide x about 20 metres aeep. mine month. r r ^ ite d " > ^ A sto,os The asbestos o.e was being sorted into two grades i.m "` ' L * 'A l b e L "or'e " I t o plants. The run of the mine ore is sent to a proeessmg factory at Udatp supplied as heat insulating material to various plants. 7. Observations (a) none of the mines mediea, examination of the others - being e rrin g onh The Dmeciot ` ' of Mines Safety informed .ha, the medical exam,na on o the - ? in. * - * Ajmer District; in fact, no facilities exist for such an exam.na ,_ . , ,, ,,,,s,;nqt the hazards of asbestos dust in the mines (b) No protection was provided for the workers against the hazar and no arrangement was provided fo, the decontam.nat.on of them clothes ,, dust. Visit To Units Processing Mined Asbestos Ore And As h e s t o s F n ^ O n J ^ t ^ i* These units are located at Beawar and on the road to Beawar from Udaipur. 8 gjinrihari Minerals-Gomti Chauraya 0 ' (- The mined ore is s u b j e c t ^ following unit operations to separate the asbestos irom ore: -- Jaw crushing. -- Pulverizing. i -- 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. ju.'.;i (b) Observations rt~"-li _ several of these operations to process asbestos ore into asbestos fibre are h.g > prone especially sieving, feeding to pulveriser and filling the bags. No dust collection system and exhaust draught arrangements exist Thus entire wo, -- atmosphere ^contaminated with v.sva, dust that ino,odes ,,beams hbre dusi. _ Due ,0 the above, dust is seen in ah ,h . places, eg. on _ No dust measurement are carried out but ,t is obvious that dust count. judging from the general dusty atmosphere. _ Personal protective equipment was not available. f*. L; _ NO provision exists to keep the w orker, working eiothes and street ciothes separate,, _ No Medical examination scheme is existing/provided. _ Very young persons are empU---1 -n the plants. __ This unit is not reported to be covered under the Factories Act.  v 37 Diamond Asbestos Co. Deog. rh, Chnuraya. y wa/^about bove. roper per month, irat Asbestos The following unit operations are earned out to separate the asbestos fibres from the asbestos ore: ta) Jaw crushing, sb) Pulverising. cI Cyclone collection. use in steel s ore is also <d) S i e v in g tire fibres. if) All tilling and transportation operations are done manually using tagoras and powaras. The observations on the working conditions in this unit are similar to those of the Sindhari Minerals, Gomti Chauraya, mentioned in 8 (a) above. |4 The Director ; lipur District the same inthe mines in AtWUot-ccmcnt Sanitary Ware. Th factory also manufactures sanitary wares, bends, joints and other accessories. Following operations are carried out : u i Mixing asbestos fibre and cement and then, water. 1 1 t in the mines tring working i asbestos fibre *|fj Moulding of the product. U i Drying. -s finishing. iKt Caring. Di jhrvc operations (a) and (d) are dust prone and, again, no precautions are existing, f h r factory employs 9 men and 5 women. |f Mineral Trading Corporation, Deogarh. Kamli Ghat. from ore: i* nsif-km about 7 men and 5 women. The factory processes about 10 tonnes of asbestos every Different grades of asbestos dust and fibre are pulverised. The pulverised material is collected 4 s curried and dumped or filled in the bags manually by tagoras and powaras. Different grades i ,.s yifffwrcd, which depend on the fibre content. O W ftillo a. N ventilation or exhaust draught management is provided. or lev* the same as in other factories, described earlier. The working conditions are. |X s*Mt* Mineral Trading Co., Beawar. .re highly dust ; :>employees are engaged in manufacturing activities. VAi asbestos is pulverised and stored in chambers. After chamber rtcivo manually. The material is then graded and packed manually. is full, the material is OW rvatlons. ,s, entire work ist. , Is, floors etc. ts wil. be high, es separately. u ' The entire area was contaminated with asbestos dust. C : The operations like pulverising, bagging, transportation etc. are more hazardous opera tions in this factory. (Kt There is no dust control and dust collection systems, ids Ihe unit is registered under the Factories Act. gx puI Asbestos Pipes, Beawar. U employees seven persons and manufactures asbestos cement pipes and bends. Asbestos and cement are mixed in the mixer along with water. The mixture is poured over different mandrils for mitrent diameters. Ihe pipes are dried in the open. The dried pipes are finished by wheel cutters m cry s;..te. 38 Observations. are exposed ,0 dUst during mtxtng and a, the Gnishtng operations. <b) No arrangements h ,, e been made to proride respirators a. these places. 14 Lachuram Balaram Kunavat -Beawar. The unit employees about 45 women and manufactures bends and othar sanrtary fixtures. Asbestos powder and cement are mixed in .agoras manually, along with water and the nux r used for making moulds for bends and other fixtures. Observations are similar to other asbestos cement sanitary-ware units. 15. Qpneral Observations. ' (a) Most of the processing operaottiinoxnrrsc narme hheeaavviillvy douusstt pvrone. Mixing and finishing operations 1: A C. sanitary-ware units are also dust prone. ' u a ot prrntml svstem nor any dust suppression arrangements, rsultait ( T gh erb than permissible luniu A study of the measurements of dust levels is recommended. , . nractices when dust levels are higher, require provision of persona W maintcinancc ud, the prov.sion of change rooms. No sec: facilities exist in these units. (d) Under the above conditions, settled dust is seen every where which can increase baekgroan. dust counts. (e) No medical check up is reported to have been carried out whether asbestos-rclate c of a general nature. The Team recommends the same. (f) The Team observed that some young persons were employed who stand a higher nsk ot a dust related problems, including those from asbestos. (g) General safety standards also leave much to be desired. 39 rations- VISITS TO ASBESTOS FACTORIES IN HYDERABAD AND BOMBAY APPENDIX `B' HYDERABAD try fixtures, er and the mix is 1 AWto Cement Products Factory : 17,1.85. !# Addition to the Team Members, the Director of Factories and Boilers of Andhra Pradesh and 1 IN# o*ffIiAcae. rs vi.ins.i4t.eJd this .41_*_ TF' ac.tory. ling operations in ' j mcnts, resulting' iotli the general.. >ermissible limits.. vision of personal' rooms. No such . V,r i d pC P,ant^ nn 0bserveduvari0us operations in the manufacturing process. The asbestos 7 ! L r7 T m 38 f0rm> The bag CnterS 30 aUt0matic ba opening machine the fibres are dropped m the Edge Runner and the empty bag comes out separately Water * 10 ,he Edfic Runncr Mil1 t0 make tho fibres wet .to avoid generation of fibrous dust The 7 afC ro,xcd and thcn used blending. The Team also observed a new bag opening machine * * 7 T T bSCrVatl0n gIaSS window- The fibres in the wet slurry form are mixed wfth cement * " c fUrther USCd f0r Clthcr makin8 asbestos eement sheets or pipes. Handling of asbestos from tt* K *tm S age to the wet mixing stage and after making cement slurry, is a closed system. ' I V wf tutting* of excess sheet are collected and sent back for recycling. The operation of finishing ****'*'* aho obscrvcd- The operation of cutting the cured pipes is done by circular cutter which ! * ti!ortivc local exhaust draught arrangement. Similarly, socket cutting and the turning machine I* Hmi provided with exhaust draught arrangement. reasc background :, isbestos-related of higher risk of all has installed central enclosed filter bag system for handling the exhausted air from IK* different operational points. The factory has also installed a central static vacuum system for h> Miction the spilled asbestos from all the working places, TV reclamation of the broken sheets are done by cutting. This cutting operation is provided with 'a ter pray to suppress the dust'. Medical Surveillance Unit Ir.f unit !> equipped with X-ray unit, Micro Processor Controlled Recording Spirometer and a clincal UVr*tOT> with a full time doctor to implement the health surveillance programme. Records of the tusniiPj;* are kept seperately for every employee. t aiiroarocnial Control. H e Company has regular environmental control system. ".isRtasfKd. Santi Scale Asbestos Cement Products Factory : 17,1.85 Audited and required records are C t fc-un, then, visited a small scale factory engaged in manufacturing asbestos cement pipes ' packasc IS chargcd mt0 an cnclosed Edge Runner Mill manually. Disinterated asbestos ^ k a c d at the outlet of the Edge Runner in bags. There is no provision for an exhaust fan arrange- at toe inlet or the outlet of the disintegrator. Opened asbestos fibre is manually weighed and to gunny bags. Asbestos is then mixed in mixers with cement to form slurry for manfacturing Tftc operation is of wet type. The pipes are cut to size by use of a circular saw. Dust is j-isci-iicd during this operation and the workers were not provided with any protective equipment.*I, Sole Non-Cement Asbestos Products Factory. I, T V Tra then visited the factory engaged in the manufacture of clutch plates. Abcstos fibre is kept as drum. Asbestos is then mixed with phenolic . resins. The mixture is used for making iiaieti plate by use of power presses. The formed clutch plates are then subjected to grinding urrUtotti where there was no draught arrangement. 40 BOMBAY NNoonn--CCeemmeenntt Asbestos Products-F--act:o-rg-y---:--2-6--.3-J---5. --i 1 " fi , iirK f o/r -3 o< xhis company nmnuiaciuixs The Study Team sited this Factory in the' j 8SbK ios textile products, mill hoard brake lininSs/clutch facings (frietton materralsl, CAF jointings, etc. (a) I^Vri-c*u-o"n Mnferials/CAF Jointings Plan"t _ ,,. . , a in the case of Friction Materials and CAF Jointing wo o The manufacturing processes observed i with other chemicals processes Iherc once the asbestos fibres are fed ,u,0 th e m x e t j ^ f;.cliol( Z i * . we, binders, the fibres get eneapsuiate^- materials and rubber solution for jointing mate J 1 conditon and all further processing m c l u d m ^ wet form. The materials are then cur * The mixing operations where asbestos fibres a ^lader d ^ ^ in wct ^ J of the linings/sheets are in x form> shape and size. , the case 0f the Brahe Lining ^ charged nt0 a bottom opening Plant, the pre-packed asbestos fibre.b,S. * the`bindcr. This bin is raised and the raw materials bin along with other raw matenafc,m| ^ ^ w th sufficient negative pressure. In the case are charged into the mixer body hoppers of the mixers with negative suction at of CAF Plant, the asbestos fibres are fed i emission. in both cases, the fibres dust level N the feeding end itself, which ensures neg igi u within the 2 fibrcs/cc level recorded in these operations (as per management records) nnnding Linings and facings so produced, are machines/dnlling machines where adequate d ^ o l i d e d to renJve swarf the case of jointings, the sheets are I ir \ " u r f i ; , ; b i: r i ; e ^ : S,l,w0er: P r id e d witb e,eboti,,e dust collection systems wherever it is necessary. The Team then visited the Asbestos Textile Plan, of this Facto,. (b) Asbestos Textile Plant in the manufacture of Asbestos Textiles nnrk.d negative suction at me The blended fibres are then fed into ained in total enclosure of flexible curt^ "^ J suction is provided on the various caiding mach Adequate The o perators required to work inside ib: ^ ^ required t0 wear On-n e- : e" T s f0Trhem" ^^^^^ n - e ci^P P ^.s inside the enclosure is done with the help of centralised vacuum collect,on system. It was also noted that the card stripping operation is c ^ rie ^ &^ cncloscJ stripp ~ nt enablcs ,, l e a d of the card are collected into a bagging unit for easy P - -- -- r The carded sliver is then spun n wct ^ ment so that the dust emanation is con aine a,,d no, proue to t.leuse of dux, T,,e spining rume e ; f doffing yarn arc also cleaned tbe n o t ^ any spillages with the centralised vacuum suction system, hurt , i dried b e f o r ^ p :m k ! ,V u ^ du.d Process machine work stations viz, carding ~ r co,,r a i ,,,, a,, an8cmMts Ire lCs Surveillance : ^ Cl th and p laite d P a c k igs arc weavine ^"nd/0 packing PaPer- All the indivi- J ' The Company maintains extensive records n fh 00nu . . mdudmg pre-employment records. These records includV clffiffiffi5 6mpIyeeS Ver several year puimonary function tests. All the employees of the r examinations, chest X-rays and Company Medical Officer. P ** ^ C mpany are Periodically examined by the Kfutroatnental Surveillance : Doit level monitoring were also observed to he p r y i n g stations. They were also found to be well ^ ^ C mpany at he various mrsiurcmcnt equipment. ^ Pped in the areas of dust monitoring and .CtWria* Textile Plant : 26.3.85 With * " cker facility, spaced well apart to Asbcs,os > at Bombay in the afternooa of 26.3 85 Z z t z z z z j z z z t cm andfcd ,mo ,he Feed a ^ -b' r a id e d a, the hoppers appeared ,,adequate y "" ^ Hoppers' The !>**> The f -- - ba ' was ilwuld be performed with persooal protective equipment." 0 "* y Cl' aned- S"cb an operation cntcring^h^spinnhg/douwing'flye^Th^Compa^^h03 Wh' r<! 'h' y W a S bdDg wc,tcd bfore periodically clean .he frames The Company has ms,ailed centralised vacuum system to Some of the sections of the factory were not working Oih.r * etc. are located in another factory, which the Team could J v i s i t ' S"Ch The Team could no, see any medical examination facility i,, this Company. " " " "S' Pla,,i"8 1hl` is a small unit, with less than 150 workers. It e blending operation is done in a totally enclosed system and the blended fibres are then fed ..-sc the hoppers of carding machine by pneumatic conveying system, Z Z Z T 1 " * ? PlaD,' iSi m ` " ed n * German dust specialist h a v in g , system of p,pe Imes reaching all the working areas of the factor, premises . r r ,, ;he carding ,s equipped with devices to extract and transfer the dropping, p,,ellma.i- ; `l ,m Z ' f T ' r ~ T Clta" ine P,am - The dust extraction plan, clear, card ,,ripping d lT Z Z Z Z ma' " - " ad' " a "d k " ps the fioor. machines, waiis e,c. CZ of the mansgemen, mention d ,,pcrators are provided wi,h Ori-nasai respirators. ors .1re also provided wherever exigencies of work so demand. u *,lrr< are pro' idcd with two sets of lockers away from workplace. Airline rnmrnimmmmi 42 DETERMINATION OF AIRBORNE ASBESTOSN !*)R!' CONCENTRATION in WORKPLACES BY U G h l MICROSCOPY (MEMBRANE FILTER Introduction or b.it experience has show" that m s m bv elineretit h ,b o ra ,o r,a s, ood by d tfrcrcnt , n o rU rx , , ,, i.u t These hin'crcnccs can a tse one n> ^ ^ ^ ^ p l f c e :w c r nt n ^ l c T a r Z . " o 'b ltn ln u n is c d by srrrc, atlherencc to these end t y o riv . v s he procedures. Scope and field ofjrpplication rncUiod ap p lies to m easurem en t o f the num be, concent,-at,on oi a .r t .o ,, ` counting criteria . TM mc,, ,od is ,, , n ,,e. .s TM 2 M c , e r i s t i c s or Phtttethnr hbres e .y . asbestos. The use ot this method hes ,,nutations . .... '"f e!s, .....tntf.Vi m ierositopy, eleetron-ntteroseopy. X - R . , crystallo graph y ere. ........ -- ! r ^ r ^ r r x c :^ .= r ::r .:- c ',- , under estimates of asbestos exposure arc nunm used. S General Method Description ' 7 7 7 7 7 2 2 7 7 2 2 , by drawing a measured ,,n rntttv hartcry operated sampling pump. The membrane alter is a a b atten operate i ; _n ,, cim cn is then exam ined under , o p tic a lly hom ogenous sp e o m e n . The spCCU . ,ire cxp reSsed as am an` d th. e fh,Kbrrpess aarree ssiiz/exdu aannd co u n te d . T h e resu lts a rc u | i thc m easm o f a ir, c a lcu la te d from the n um ber o f h b .e s on the Hite un or:' !n: c '..us u ' . r 4. Sampling Apparatus And 'I'echniquc 4.1 ITtei M ^b ran d niters (mixed esters of eelltilose' or ecllihose pore si/c w ith 25mm diam eter should be used a t:,.o 4.2 Filter Holder 7 is n ecessary to use an open face fib e r D ue to design o f die ill filter h o ld e rs, a sup p o rting pad o f larg e r pore s,ze . s h ^ i K - ; ;m; pad .s to ensure an even d .str.b u t.o n ot a .r passing t h .o i . ^ coo p ' ooen faced filter fitted with a p io te c tiw m e U L .c m tc Y fro T a c a d c n ta l damage and contam m at.on But recent c' ,,necessary rf proper care ,s rate,,, and toe o, cow! K.h ; vu or ouir' ii 1m iicl ;c bu: :on o hecatrse of electros,a,ic charge I, develop, hue .......... . Ao*i Transport He t.tjiisc must not be used. Ltr--t-cnee has shown that fixing fibre to the filter surface with cytological fixatives or other type !.:a c ' is unnecessary and should not be done. : f rhr:, s! ould be transported in closed holders, which should only be opened immediately ' ;' use and sealed immediately afterwards. f r r A.'tcinativc method is to transfer the filter to a petri-dish in the following way : In a dust free ~ creeps, carefully remove each used filter from its holder taking care to grasp it -V '*.) wr.cxp.ncd edge. Place the filter, dust side up, in a plastic petri-dish or similar container ' f s t t.vo pieces of adhesive tape attached to the unexposed edge. After transporation, *.-i can he easily removed from petri-dish with a surgical scalpel. T-ltcr holders or petri-dishes into a rigid containers with sufficient soft packing material ' *''*11* N'db crushing and vibration of die filter. The samples should be unambiguously labelled in i s ;s netcvsary to ensure that filters cannot be accidently reused. The filter surface .**rn,*:f i Kf marked for the purpose because of risk of damaging the filter. '*1 ,3 **' operated pump must be used ior, personell sampling. The capacity of battery ' t ' *1TM eient so operate continuously over the chosen sampling time. Thh flow must be ; scum and tentative criteria there must be no visible vibration of a rotameter float when -*.-v t f . i connected to the filter holder. Although some pumps are equipped with pulsation e,i r-i an external damper may have to he installed between the pump and the filter. Never - ; r - rr;P without a filler. The connections should be leak proof. ? ^,:c models of personal samplers have automatic flow correction devices. Such pumps i- a -t be preferred. r Haw Rsu IT? JS,,.i* We ifetrwkd be to 1 hue per tninuic (this gives approximately 4cm/second face .n v -js- - T%j; -j jo , ifcft.t.. h M tisa-aU be th tc ic d allcasl before and after sampling; if the difference f t v** t&t attul daw rate, the sample must be rejected. r T*?tf m a s t n used to determine flow rate of the pump, care must be taken to r> f se * mrur doe* not cause unknown changes to the flow rate. The flowmeter used *? in sf.e*re flow rate to an accuracy within :i; 5% of the true flow (95% confidence '1;f? t `'f '* r a t e c a lib r a t io n see Anncxuic i.) Sav-j*< t fh tt t osiheg. on Killer* *1 t I .Sing. t.raa 7i load mi' on inter should be 50 libres/mm2 (i,e. approximately 40 fibres per Walt Bcclcll Graticule Areas). The lowering of the acceptable fibre loading gives cccpialdc soeflicicnts of variation. 4 * M* *.* Indiog ` w &:tfi W t n * ' houiu not cxcccd a maximum of 650 iibre/mm2 (5 fibrcs/graticule area) for * * * > ? ' * ) ` f u\uih,a%. The avet ago filter loading exceeding 5 fibrcs/graticule area, tends to U i ' ~ i u*` C4imul," a,ul should be treated will} caution. This may have to be further t.*n average u fi fibre, graticule area when mixed dust agglomerates are present i4* jir.fhmes he doubled if only fibres are present. Average filter loadings exceeding ;Tii'r 'aticulc area must be rejected. 44 4.7 Blanks. _ ^ {liters m the batch, select For 1 . batch of niters tedfor h l t e r which has b e e n s u b j e c t e d l " ,, removed, havmg art drawn through ... Ws hr. conn, greater than 3 Bbre/H 2 Shonld be examined carefn, , to J o r |n v m b e e n o, l t be e *>TM" ' S'U",1' attached to tm s J - " ' r t und ' contmma,io,,. When . ,,,t lu:, o r e ; . exceeds 3 hbres/100 graticule blank * not e o n s . d e , e, ace. grarrenic areas, the a n mag s t d , b e Of w o r k e r e x p o su re . H o w e v e r , i m a t c d e x p o s u r e is l e s s m a n t l - t ^ ........... with the hygiene standard (e.g. ^ conservative estim ate ol ee npi.,..-- , even with the co n ta m in a tio n then w as 15 fib re s /100 c r. ricu le i r e . ' F o r e xam pl/e T he fibre count of a blank 4 he here f ^ oq hbies, a: m a tie u le a ic a s (i.c. 1 - J j- a r e a ) while t h e sample yie ld s 108 f i b r e s n - B l a n k C o u n t 0, ^ Sample"Count T JT _ L " x 100 = 12 5 % . , F u r th e r m o r e b x r.tc r As this p e r c e n ta g e e x ce ed s 10, the s^ m p f contamination must b ; tom d , - exceeds 3 fibrcs/100 graticule areas t h e cause 4.8 R cco n in icn d e d ^ i^ e ^ S a n ij4 i-J [2 ^ -- . , tio m as d etailed m 4 .6 , the du 'r ,hc 1b " " i,,s 10" rui:' A___L__ J__ t - ' a Cexp. r t - Single Sam ple Duration. 1L = sqguired filter load,ing :mn lftibhrreess//gg r a t i c u l e a r e a . A = effective filter area m m 2 a = oraticule area m m 2 . o n e x p e c t e d , occur d ,, r , , . . . . 1r> [ ; li. 1, mi T o provrde :r ;t = " ,lhr C" w ; n g sampling the MnD*e o i limit. to n ,co n shordd prctcnrbiv be tint. . Single Sam ple D uiation Expected fibres/ml. 0.1 0.5 1 2 5 10 20 * m i n i m u m (.3) 3.3 h o u rs 40 m inutes 20 m inutes 10 m in u te s - (4) - (4) - (4) i e c o m m c u c id lull shift 3 houis 1 5 hours 45 minutes 20 m inutes 10 minutes H) m i n u t e s ot . v .,, .w : ior .c, - 45 ne unused, having the his `1 A lical proceiank count : count,' 100 assessment complianct ' regulation 0.15 fibres 1, : 2 fibres/graticule area. 2. : 5 fibres/graticule area. : 0.4 fibres/graticule area equivalent to 50 fibres/mm2. a : Sampling periods shorter than 10 min. are not recommended. Sampling time should be measured within 2.5%. The timers oi counters installed in some 7 _,:r.ps are not always reliable. i * sampling Strategy and Records f rious types of sampling schemes are given in Annexure II with advantages and disadvan< All data necessary for the determination of fibre concentration must be recorded along .. :i dimpling details. An example of sampling and counting records is given in Annexure III. blank count rected. . ion for each nple Duratiolists recom: bie to use tht still remain; is compliao the appropri; laximum (2) jll shift hours hours hours hour 0 minutes .0 minutes i I sample Preparation * j i Cleaning Slides and Equipment , Clean conditions should be maintained at all times. A dirty preparation area may result in sample contaminaticn and erroneous results. Clean slides with lens tissue or industrial paper tissue and lay them on a clean surface, e.e lens tissue sheet. It is good practice to clean each coverslip with lens tissue immedi ately before use to ensure that the surfaces are free from contamination. Wipe scalpel and forceps with lens tissue and place them on a clean surface, e.g. Sens tissue. When mounting a series of filters, the mounting tools must be wiped clean before dealing with each sample. < j ' Kilter Sample Cutting Mounting of the total filter is preferred. If it is necessary to cut the filter, all cutting Should be done with a scalpel using rolling action. Do not use scissors. It is recommen ded that the smallest piece mounted be wedge-shaped, approximately one quarter or one third of the filter. 5 j 3 .Mounting the Sample For mounting use" the acetone-triacetin method as described in Annexure-lV, unless ,i modified refractive index has to be used. w arning Acetone mounting should be carried out only in a fume hood or fume cupboard. On no occasion should it be conducted in the vicinity of an open flame. * ; Optical Requirements * : 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 give quite different performances. Thus it is necessary that performance of microscopes Should be assessed by means of HSE/NPL Detection Limit Test Slide Mark-II (See Annexure V). Prorovidcd detection limit criterion is met, small departures from recom mended specification can be permitted. It is also important for newcomers to consult experienced users before selecting microscopes for asbestos dust determination. The necessarys peciiications are as follows : 46 fa) Light Source : Koehler Illumination is required. A built-in illuminator is always preleiable 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 Assembly : An Abbe or achromatic phasecontrast condenser incorporated into a substage unit is required. There must be a means of centring each condenser annulus with respect to the phase plate in the corresponding objective and a means of focussing the condenser. (c) Stage : A built-in mechanical specimen stage fitted with slide clamps and X-Y displacement is requied. (d) Objectives : A rotating nose piece fitted with lOx and 40x objectives, must have numerical 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 phase constrast is suitable but positive phase contrast is preferable because it gives brighter image. (e) Eve pieces Binocular eyepieces of compensating type are recommended. They should be chosen to give a total magnification of between 450 x and 500 x, preferably 500 x. Atlea.t 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-Beckett ciiuilar eyepiece graticule. Its actual diameter when using 40 x phase objective and appropriate eyepiece should be 100 um 2 um. (See Annexure VII). (g) Accessories : 0) Centring Telescope or Bettand Lens-- is essential for checking that the phase rings the condenser are centred with respect to those in the objective. (//) Green Filter--is necessary to ensure the best phase contrast conditions because the optics aie designed for this wave length. Stage Micrometer--must be subdivided into 10 um intervals and preferably be on,, (H i) millimeter long. (iv) Microscope Slides should oe of the best quality. (v) cver Slips--of thickness to which microscope is designed are essential. Incorrect coverslip thickness will detract from the quality of the final image (Normally acceptable thickness of coverslip is 0.12 mm to 0.17 mm). (vi) Band Operated Counter--This should have two columns, one for No. of fibres and another for fields. 5,2.2 Microscope Adjustment Principles Follow the manufacturer's instructions while observing the following guidelines . (a) The image of the light source must be in focus and centred on the condenser iris oi unmake diaphragm for true koehler illumination. (b) The object for examination must be in focus. (c) The illuminator field ins must be in focus, centred on the sample and opened only to be 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 checked b detections limit test slide. All microscopic adjustments must be a daily routine. (See Annexure VI lor details). 47 1 Is preferable T ght intensity ' ' * * * rated into a a phase plate f displacement ve numerical . n 65 percent ^ native phase f> gives brigh. ter 9Ant`, it. 7. icy should be |7 x. Atleast |j | jp f ssingtype. ST i Graticule Calibration f k " combination 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 m pc>, calibrations will change for observers with different intcrpupillary distances. Aancxure VII). Xfc.-r.a-fgp<r'Observer Performance Assessment i.ur past experience has shown that significant differences in counts occur due to differences ,`s * vwopc quality, setting up and cleanliness, it is necessary that laboratories following this .f'U-O should maintain contact with those having experience with this method. The practical limit of microscope should correspond to Block 5 on HSE/NPL test slide Mark.11. r of microscope slides for comparison with experienced laboratories will help to ensure *A d results are being generated. i: a Trt.iisb'c to determine intra-observer variation to assess reliability of an observer and in case, # 'tiHsiitofy employs more than one observer, intera-observer variation must be determined to systematic variation in results. .... ^ Siring Fibres l IV Scanning ckett circular id appropriate"1: V-A-'' .se ri.ngs -in 1th1efjft-'- Uv is b, ecause ,1,1reIf a u i 'erably be one. Liai. I n c o r r e c t ; . nally acceptable fe rj, i total magnification of lOOx to 150x (i.e. lOx objective) scan the entire filter area. The r-fl.t pcs normally covered by the filter holder gasket should be free of dust and fibres. All -w'su## &tkli should have similar appearances with respect to total dust loading. If the observed i.T.in. marked differences in loading or gross aggregation of fibres or dust, the filter should be -i The filter must also be rejected in case the background dust is high and interferes At -itts#tiSDg and sizing of fibres or the filter shows any folds, kinks, or gross distortion due to mounting. ^UmnaHiwoniMnw--IF!ik.i..d...S..e..l.e.c..t.i.o. n lA-ei irtfaetory low power scan change the microscope objective to 40 x phase and focus on -Wi Jue plene. Ensure that the phase rings remain concentric. Wnile most of the fibres and dust ii the upper surface of the filter, it will be necessary to focus below (say upto 10 um) .-is* above the surface. When counting and sizing, constant use of the fine focus is Keause of the small depth of focus of a 40 x objective (i.e. 2-3 um). Counting fields N ifeoten at random throughout the entire area of the filter or filter segments. In case a ij-As >- >}?ff has been used for sample collection and the grid obsructs the view the field should civ.! D o not count fields that lie within 3 mm of the filter edge or within 2 mm of o f f i b r e s anC : 1 > i. Working Conditions er iris o r annulaf " s,.. practices and the working environment in a laboratory may influence systematically ficy of the actual counting. Some differences may appear when inter-laboratory , ,.sy. a r e made which arc due merely to different laboratory lighting conditions, different computing arrangements etc. Different practices of recording data may also cause * ..t I ,,,,c-'ccment between counters, due to the rate of fatigue of the eyes. ned only to the writing of data involves the re-focussing of the eyes after each field, whereas conli j . , , jitte r in g with electrical or mechanical counters involves only a single period of f -.s'f :A concentration. on centric. t be checked bfjfi Dr details). t Criteria ail particles having the following geometric dimension as fibres : greater than live micrometers and nrtor less than three micrometers and i.'Sfth to diameter ratio greater than 3:1 48 Accuracy is important, and full use should be made of known dimensional standards. the length of curved fibres along the curve of the fibre (i.e. true length). Estimate - When examined microscopically, asbestos fibres fall into four basic groups as follow s : -- 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 distinguished. Where they cannot be distinguished as individual fibres they arc counted as equivalent to one fibre if the bundle has a total diameter less than three micrometers. -- Fibre attached to particulate matter are counted as one fibre if the diameter ot the particle is less than three micrometer, otherwise not. Refer to Annexure VIII for full details. - The counting rules are based on the principle of counting fibre ends, visible within 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 counting area. Count as ` H a lf F ib re ' any fibre If a single curved fibre has each end inside the counting area having crossed the area twice, each end is still counted as half a fibre. - Count as many fields as are necessary to give a total fibre count of 100. A m inim um o f 2C fields must be counted, even if more than 100 fibres have been observed. It is not n o c e u r ) to count more than 100 fields. However, errors will be large when the m inim um libres or fields are not counted. All relevant information must be recorded. (See Annexure HI for an example of a dus counting form). 3 5 4 0 Calculation of Dust Concentration and Worker Exposure When the following calculations are applied, the limitation imposed upon the data by tin : sampling and fibre counting methods must not be disregarded. Results should not be interprets f.- or reported with false precision. 5,4.1 Single Values fe' t Ih e fibre concentration for each Single Sample Duration is determined according to the follow,n formula : , P,* where i c = Concentration (Fibres/ml) N -- Total number of fibres counted. n = number of graticule areas observed j- ,-3 A -- effective filter area (mm2)--See Annexure IX a = Graticule counting area (mm2) r = pjow rate of air through filter (ml/min) t *= Single Sample Duration (Minutes). Time Weighted Average Values. `Ar.cn several samples of different sampling duration are taken, calculate the time weighted virjge values from the single values as follows : CTW = SC< t< S t. Cl ti+ Cjts H--------------(- Cotn (2) ti + t! i ------------ tn Cl W =- time weighted average concentration (Fibre/ml) e. = Single value of concentration (Fibres/ml) it Single sample duration (minutes) -j =- Total sample duration. n, -- Total number of samples. i. lr :>.c single sample durations (ti) referred to above arc of equal duration, then equation (2) is i;r;'!sfied as follows : CTW - = ,c l + c 2+ n n ~ ,c.'C (3) * 5 lttjulent Eight Hour Exposure Value (Ceg.) T T,r shift of the worker exposed to airborne asbestos dust is more than or less than eight hours, l concentration during the full shift must be multiplied by a factor (f) to yield the Concen- iCcq) as follows: . _ full shift time (hours) 8 hours. W Ceq = f. CTW (full shift) (5) f t stfle 1 * shift duration 12 hours ; time weighted average for the full shift of 1.2 fibres/ml. Using equation (4) f = --1,,2-- = 1.5 Using equation (5) Ceg = 1.5 X 1.2 = 1.8 fibres/ml. I.vtaaplc 2 : ifA.ly shift duration of 5 hours with a corresponding shift average of 1.2 fibres/ml. Using Equation (4) f = --5O-- = 0.625 Using Equation (5) Ceq=0.625X 1.5 = 0.8 fibres/ml Txs: .means that the worker was known to have zero exposure to asbestos outside of his 5 hour CViJt l } < kaUtion of Ceq for Various Sampling Schemes. Tt p a --A,B,C and D. ' i Calculate single value concentration (s) for the sample (s) using equation (1). T Calculate time-weighted-average (CTW) concentration using the above single respective single sample duration(s) in equation (2) (or (3), if applicable). ? QUculai Ceq by using the procedure at 5.4.3. value (s) and 9 `-I ; i /"v V-' I: K{*<?: P: r>` f*-J k* : l i is. , ^ : \ \ W k..; ) <- . iv ,-ii 50 5.4.3.2 Calculation of Ccq for Sampling Scheme (E) Type `E' When 5 or more short term samples are taken randomly through out a full shift, the ti m. , weighted-average concentration can be estimated as follows : 1. Calculate the natural logarithm of each concentration Yi--In C(, i.e. Yj --In Q , Ya= ln C2 and so on, if any concentration is less than 0.1 fibres ml, replace it with 0.1 fibre/ml for the above calculation. 2. Calculate the arithmetic average of the logarithmic concentrations. f = SYi = Y 1 + Y 2 + ------------ hYn n n 3. Calculate the erppirical logarithmic standard deviation (Se) of the logarithmic concentiation(s) (sampling/analytical random errors and environmental fluctuations are included). Se = 2Y2, - or Se - Yi2+ Y2o-I----- bY2n--n(y)2 4. The estimate of the average airborne concentration is calculated as follows C TW -Exp r - s 2, ~ 2 NOTE : The above calculations are used because avalable evidence shows that random intra-day variations are best described by a log-normal distribution. 5. Using CTW from above, calculate Ccq as in Section 5.4.3. 5.4.3,3 Calculation of Ceq for Sampling Scheme (F) Type --`F ' 1. Calculate single value concentration(s) for the samples using equation (1) 2. Calculate the items (Ti) for each individual working phase ensuring that the sum of these phase time equals a full shift. 3. Calculate the time-weighted-average concentration using the phase time (Til instead of 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 identical reliabi lity in the estimation of the equivalent 8 hour exposure value (Ceq). 6.0 Sampling and Analytical Errors 6.1 General Errors introduced into the estimation of airborne asbestos dust comprise sampling and analytic..! errors, each of which has a systematic and random component. The application of standard procedure and a reproducible routine is the only way of controlling most of me many sources C errors inherent in the membrane filter method. The following list desetibes so in: of the coni n u sources of error. 51 t *,,j Sin4fOElic E rrors : * I Sampling: out ; 11 shift, the tiras;ion is less than 0.1 fibres/ I'lovs rate - Sampling time Non representative or biased samplings. Contamination --deliberate or accidental *.2.2 Analytical : is. re logarithmic concentra' ituations are included). Fffcctivc filter area Counting area Counting criteria Filter mounting Microscope and observers Contamination - & l 1t**4*m E r r o r s : 11 *. \ I S a m p li n g : ]" flow rate variability. ` Itindom fluctuations of the airborne dust cloud. SkJ. i Analytical : fibre distribution on the filter : as follows : >\vs that random lntia-dayf i 1 r ation ( 1) ring that the sum of these ftM >c time (Ti) instead of the .-.'' ib;, i ot imply identical reliabi- Ceq). sampling and analytical. 1 application of standard ' of the many sources of ; essoin.- of the common f- 1 Non random deposition of dust on the filter leads to gross errors, the magnitude of which a n net be estimated. Twenty or more fields must be counted to ensure that minor mergence from randomness does not bias the result. Pnivwjn errors: A* only small samples of the fibres deposited on the filter are counted, errors arise in the Jmution of the total number of fibres on the entire filter face. Theoretically, the Poisson deunhuiion defines the variation in fibre counts resulting from viewing randomly selected iswiMing fields on the filter. If a minimum of 100 fibres is counted, and if a Poisson JtWfibuiion is appropriate to the counting results, the relative standard deviation of the fibre iouniy would be 10 per cent. It has been shown experiementally that the actual distribu tion of fibre counts can depart from that of Poisson, in which ease the standard deviation t5uy be greater. 0rrii Accuracy : of the nature of the membrane filter method, it is not possible to know the true airborne StA^c concentration of a given dust cloud. For this reason it is not possible to assess the likely of the method. Even the precision (or repeatability) of the method is difficult to quantify of systematic errors which tend to arise from both intra and inter-laboratory variation. T-ilen as a whole by " randomly" selecting observers and laboratories, these systematic errors lit on random natuie such that it may be possible in future to provide estimates of cmpiiica! *tic<ujon fi.c. the closest approach possible to a statement of accuracy for a method with no "true" values) Mwcb work has been done in an attempt to arrive at these estimates and todate only partial tcluiions have been reached. One of these describes the theoretical Poisson distribution (See M-cfioa 6.3.2) as contributing a 95% confidence interval of 35 percent for onlv 40 fibres i^-wated in 100 graticule areas. O.Fcf tourccs of random and systematic errors add significantly to the uncertainty in estimating ijitsjrnc asbestos dust concentration. Timitations oi tne memu...* *.............................................. l ading sample isfo01.0022fiffiibbrreess//mml-, howeverghe ' praclical limit is much reading of several higher. It countable is generally fibres per accepted that 100 granai!, blank, unused filters.canifrequ contaminents on the filter or artifacts from the areas. These r anoearance of fibres. It must be recognised that neither counting clearing process which have the PP overComes the problem of background dust, when ra refieldS ^8in r e o v e r .ld u s T c.oudPThere is at present insudicici: asbestos is a min.mu ,cvel thc reliability of the method becomes so poo: information available to determine at ^ ^ ^ ^ ^ a single value> but Wl bc a range that results have^ " le m6a J , absolute fibre concentration. There appears to be genera; depending upon atleast . . , . th t t u,,se limits lie somewhere in the range agreement amongst those exper.eneed ,n t h B a d *h; . these ,m ^ atioa, and .Ik of 0.1 to 0.5 fibres/ml depending on a vanety of inondations. of less tban 0.1 f/m. shonld be decimal place, and to two significant figures. -- be FLOW RATE CALIBRATION AND CORRECTIONS ANNEXUREI ti4 externa! flow meters must be calibrated with a primary calibration device. The method te. os' he commonly used variable area flow meter (i.e. rotameter) using the soap film flow I' an accurate burette (or similar) of 300-1000 ml capacity. Attach a tube to the iwnom of the burette, and then clamp it in an inverted vertical position into a .kt up the sampling pump complete with connecting tube, filter holder and filter as used s the field. i,,:<oncct the soap film flow meter. Ensure that the system is leak proof. It is advisable " i:ose l*ie burette thoroughly in water immediately prior to the test-this removes accu's-Ltcd detergent and also assists in wetting the inside of the burette. on the pump and adjust the flowrate according to the internal flow mater (if till a beaker or petri dish with water plus the minimum amount of detergent necessary ; permit bubbles to be formed. H. momentarily placing the beaker against the bottom of the soap film flow meter create a f-hWc such that it will travel the entire length of the burette without bursting. Vi:h a stop watch, measure accurately the time that the bubble requires to traverse the tube tietween its extreme graduated ends. Repeat steps (f) and (g) at least twice, or more, until good repeatability of the times is u-bteved. Awrage the times, and calculate the true flow (Qc) as follows : St here Qc=Truc volumetric flowrate (ml/min.) at calibration conditions. V = Volume of burette (ml). t --- Average time required for bubble to traverse the tube fminutes). Step* fd)--fi) must be repeated until the desired flowrate has been reached within 5 %. NOTH -Theoretically, the water vapour content in the soap film flow meter air should be uken into consideration in determining the "true" flowrate. However, for practical purposes acceptable accurary is maintained without this correction. 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 different flowrate that will inevitably result. As all air sampling measurements are connected only with volumetric flowrate (i.e. flowrate measured and expressed at the prevailing temperature and pressure) and not mass flowrate (i.e. flowrate corrected to standard temperature and pressure conditions), recalibration of the pump flowrate is essential if it is operated under conditions substantially different to those of calibration. Substantial implies a difference in altitude or temperature by more than 500 m or 15C respectively compared to the calibration conditions. " Example : 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 the flowrate under these conditions? Using the equation in this Annexure : Qc V T _looo_ 63.4/60 J b ml/min The flowrate, under the temperature and pressure conditions as stated above was 946 ml/min. 55 L.I Terminology EXAMPLES OF SAMPLING STRATEGY ANNEX LIRE II E .i.l Occupational Sampling Al! sampling must be so conducted that the results arc representative of the worker exnosure to ^ " " .to to M b c workets "n<li,i nS E.1.2 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 lace, and measured from the midpoint of a line bisecting the ears. ' E.1.3 Personal Samples Personal samples are taken within the workers' breathing zone. Usually the filter is fastened to the jacket lapel of the worker with the cowl pointing downwards. The worker carries the pump on a belt or m a pocket. E.I.4 Static Samples Static samples arc samples taken at fixed locations with the cowl pointing downwards. They are not recommended for the measurement of personal occupational exposure to asbestos dust. Point sources create considerable concentration gradients thus causing the results of static samples to vary considerably over short distances. However, static sampling can be useful if the dust IS proven to be uniformly distributed over large areas. 11. t 5 Single Sample Duration Single Sample Duration is the actual time during which a single sample is collected. E 1.6 Total Sample Duration 1otal Sample Duration is the sum of Single Sample Duration taken during one shift (see E.2.3) on one person. Is.1.7 Short Term Samples The Single Sample Duration for a short term sample is less than one hour. The short term sample has been defined because it is necessary to refer to that special case specified as short term, the samples are assumed to be of at least one hour duration. E.2 Strategy Unless E.2.1 General Principles Occupational exposure measurements are carried out to meet one or both of two major objectives : (a) To assess exposure relative to an occupational hygiene standard and to enable better control measures to be implemented. (b) To provide estimates of exposure for epidemiological investigations of morbidity and mortality. It is well known that the concentrations vary widely both within a single day and from day to day Most regulations and hygiene standards require a reliable estimate of exposure on a particular day. It is more useful for epidemiology to spread the sampling effort over a number o\| ^ will be known about a single day, but more about the average exposure over a working hfeUrne Since sampHngmust often serve both purposes, the sampling schemes presented m tins method oomph size t h H . n l da estimate. It must also be recognised that variations in individual working practices result in a distribution of exposure values within any job group^ Consequently data from one person cannot be assumed to be representative of the total job group. Any transfer of data must, therefore, be validated by appropriate relative measurements. E.2.2 Sampling Scheme There are a number of possible sampling schemes, some of which are listed for guidance in the following table. As they very in the degree of usefulness and precision in estimating exposure t c table must be interpreted in association with the qualifying conditions and cautions presented in k.2.3 and E.2.4. Sampling Scheme No. of samples per shift ________ __________ Total Sampling Duration Long Term Full-shift consecutive sample (s) Type A Type B Partial-shift consecutive sample(s) Type C Type D Short Term Random Samples Type E Systematic Samples Type F 2 or more 1 2 or more 1 approx, full shift approx, full shift 2 hours or greater 1 hour or greater 5 or more taken randomly throughout the working day 1 or more plus continuous relative measurement, or 2 or more taken during each spearate phase of a cyclical operation 1 hour or greater 1 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 every effort must be made to ensure that the samples relate to a whole working day. Care must be taken to ensure that the sampling period is not biase by abnormal conditions. Shortterm samples should be taken at random (statistically) throughout the whole working day. If Lmp.e" ca,,no, be s e a te d from .ho entire working day. .he measnremen. results arc vahd only for L dnrauon of .ho period from which .he measurement, were selected. However, relative mease. ments and reliable professional judgement can sometimes be used to m ake inferences aboiu co tions during other portions of the day. Reliable knowledge of the operation is essential to ma.e s . extrapolations. - 57 i: 2.3 Total Sampling Duration and Number of Samples Sample duration is influenced primarily by the reason for sampling, the level of fibre concentra tion to be measured, the concentration of non-tibrous dust and the requirements of the analytical '"icthod. This may result in more than one single sample being required. The total sample duration .should never be less than one hour. -!.6 and 4.8 detail acceptable minimum and maximum loadings of fibres on the filter, which dictate the range of possible sampling times for different airborne fibre concentrations. Samples of short duration may be necessary if high background levels of particulate matter or fibres are present which would prevent accurate analysis. E 2.4 Reliability of Sampling Schemes The main strength and limitations of the various sampling schemes, types A to F listed in .2.2, are as follows : (a) Type A Sampling Scheme (two 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 errors such as miscalculations, contamination, incorrect sample timing, etc. are more likely to be detected by type A than type B. Note--Systematic 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 detection 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 gross ernns may escape detection. (c) Type E Sampling Scheme (5 or more short term samples, taken randomly throughout the full shift) may give an acceptable indication of exposure but is generally more wastefull of resources and is the least precise of the above schcms. Note that an even poorer estimate results when the " average" dust concentration increases or decreases markedly throughout the day. This scheme should be applied with caution. (f) Type F Sampling Scheme (several short term systematic samples taken during each separate phase of an operation) can be used by experienced industrial hygienists to characterise a workplace. This approach should not be used indiscriminately, particularly by peorsons not completely familiar with the process. Nor should it be used to estimate time-weighted -average exposure unless the results are verified by continuous relative measurements or other methods (see E.2.2). 58 a n n e x u r e 111 dDuUsStT sSaAmivpirljbiniiwg r e c--o---r--d- Ml data necessary for the determination of ^ record. Furthermore as much data as ava,table whtch can hp included. Sampling Details Q Instrument Type and No. Flowrate, initial,intermediate and filial Duration Q Sampling scheme used Date, Hour Sampled by Sampling Place Details Q Designation 0 Harmful substances-types of asbestos, qilartz, etc. n Brief description of working process O Variable parameters which can excercise an Whence on dust format,o,, Work practices ... Working conditions : normal, abnormal ... Material : type, size, conditions, etc. orking places : Airflow : worker Indus, airflow yes/no obvious influence on ad,,mug orb 0 Methods of dutt control Exhaust ventilation Other methods Visual impression . Number of employees for which tfce measuring value is representative Personal-protection yes/no Type . Hours per shift Days per week See the following page for Dust Sampling Record. 59 exam ple only dust sam pling record 0 a c e oi n'leasurcmont `.Measuring pomt/Name Dim ension ot w orkplace date 1t, ^ "- Code-No text in cle ar block let! j~ ~|< 50 m3 j | 50-500 m1 I ~|500-5000 mJ| j> 5000 mJ Exnaust ventilation 0 ,es Situation representative7 Dust concentration Visual impression j___ jabove average | "a | quite good below average bad r ju n b e i o! em plo yees working at this working place { aspirators are worn lyes I1 Draught during measurement jno sometimes Type 0 " TM' M easured in the dustladen air (low Adjoining working places yes <jre influenced n I Measurement was dune j j personal static Sa np! ng device atmospnenc pressure Air Mow rate time started time ended Sampling schem e used Sa m p le No SampTng time (mm ) I_ Total Slow Harmful substances Quarts Olone' (ihn Working phase Fibres/rnl Crocidolite n (other) Mineral wool c cc:: _ c [0 0 Average value Amosite 60 Appendix I Counted by Date Microscope No Graticule Type 0-bundles X-background not Okay Dust Counting Record (Example only) libres number of | (elds Area mmJ nt 1 c = ----- nci v libres ml In sp e cia l circum stances n is o' value to record me number ot fibres contained m individual fields of counting Example nt Sample No. nt 1 F =. Cnct V fibres ml N = n = c = concenfrafion in flores ml nt = total number ot fibres counted j_n c t = number of fields counted A = effective filter area (mm2) a = area of me counting held (mm2 V = total How (ml) F =A a (constant factor} 61 a c e t o n e -t r ia c e t in -m o u n t i n g p r o c e d u r e ANNEXURE IV The following is a description of a procedure for mounting membrane filters The device is hreely composed of parts available in chemistry laboratories. The handling of acetone requncs crcat care in order to avoid accidents. Still safer devices are being developed. They may be used providing that the same slide quality (no washing off of fibres, smooth surface, clear background) can be obtained with them. Warning Acetone"'mountin' should be carried out only in a fume hood or fume cupboard. On no occasion should it be conducted in the vicinity of an open flame. Only a small quality of acetone is necessary. Heating with the waterbath is preferred, use of boiling chips in the acetone is recommend. As illustrated in the diagram below, it is advisable to use a simple condensing column to (a) ensu c that a bare minimum of acetone vapour escapes. The free opening ,n the tap must have n diameter of atleast 8 mm, otherwise the acetone vapour cannot escape in a sufficient quantity when using an open condensing column. When not m use, the acetone vapour outlet should be closed. Heat the acetone to boiling and wait until a moderate-quantity of acetone vapour is emer (b) ging from the outlet. pU,cc .he filter, dust side up. on a clean microscope siide a. room tempera.urc-eica(c) rostatic forces usually keep the filter on the slide. (d> Ensuring that no liquid acetone drops on the filter (b , wiping the outlet periodically with <d) u,issue) hold the Slide with clean forceps directly i n "1I T 1 mately 15 to 25 mm from the outlet for three to five seconds. At t - , filter Slowly across tire outlet 10 ensure eyen coverage until filter is runsp. , vupour will fail .0 render tire filter transparent, while too much vapour (espee.a y drops of liquid acetone) will destroy the filter by dissolves ,t or slum mg n eyont slide 1 s t not be prewarmed, as the acetone vapour mus. condense on .he slrde for correct clearing. (. Using * T T f l r TO ^ Z onto the membrane. C 3 mi n : : ' s r s * . ^ ,, . f'n r-yc indicated by excess liquid emerging from the edges of the coverslip) cient triacetin will result in uneven clearing of the granularity left from the aceton vapm clearing. Further, the refractive iudex_ of the mounted sample will not be suitab c (g) Heating the cleared filter 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 triace tin. The fiinished product will be stable, will not disintegrate, nor be subject to particle migration. (h) It is desirable to paint nail polish, or similar lacquer around the edge of the coverslip it the slide is to be kept indefinitely. 63 ANNEXURE V HSE/NPL TEST SLIDE (MARK IIj FOR THE DETERMINATION OF DETECTION LIMIT WHEN USING PHASE CONTRAST 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 National 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 coverslip 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 /xm wide. A set of 4 deep marker ridges is placed on either side of the ariay and a further two sets of 2 marker ridges spaced at an interval of 120 um inteisect the array at right angles. The zone of the test objects to be usen 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 coverslip. This is illustrated in Figures I and II. The widths of the iidges 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 Blocic I (the coarsest set) of the test objects and move the slide to observe adjacent 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, LS9 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. Block Number Groove Width (/m) Maximum Calculated Phase Change (in degress) for light rays A= 530 nanometres passing through test objects 1 1 2 0.77 3 0.64 4 0.53 5 0.44 6 0.36 7 0.25 6.6 4.7 3.9 3.2 . 2.7 2.2 1.5 Fig 1 Test slide (76 x 25 mml epoxy resin replica + cover slip 65 MICROSCOPE ADJUSTMENT PROCEDURE ANNEXURE V Good quality phase contrast microscope equipment should be used as detailed in i.2.1. The equipment should be maintained in first-class condition and most manufacturers operate a routine maintenance service which includes the stripping down and cleaning of all optical components and the replacement of worn traverse mechanisms. Such services should be used unless skilled maintenance services can be provided by counting-laboratory staff. Jn general the following setting-up procedure should be adopted to obtain Koehler illumination and good phase contrast conditions but the detail may vary according to manufacturers 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 ins) and the substage condenser diaphragm. (Note--at this stage the phase annuli should not be inserted. These are usually based in a rotating drum fitted into the substage condensor unit.) (c) Raise condenser to its upper limit, usually within 1 mm of lower face of specimen side. (d) Using a convenient level of illumination and 10x> objective focus the specimen. (e) Close down the illuminator diaphragm and focus this in the field of view by lowcrng and raising the condenser. Centra 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 the body of the microscope or by removing 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 filament should fill the back focal plane of the objective. Re-insert the diffusing dist il'appropriate. (Note--if the bulb cannot be focussed adjust to give uniform bngiu illumination.) (ii) Insert the correct phase annulus into the condenser system and centre this using the appropriate adjusting screws so that the phase plate in the objective and the image of the annulus coincide exactly. Adjust slightly the condenser focussing if this is necessary. Cnsurc that the bright annulus image does not extend beyond the phase ring. (i) Revert to normal viewing and change to 40x objective with no phase annuli in the condenser system. Close down the field diaphragm and refocus this by appropriate adjustment of the condenser. Re-centre if necessary and re-open to fill field of view. (j) Repeat stages (f) and (h) after inserting the phase annulus appropriate to the 40x objective, (k) Revert to normal viewing. 66 ANNEXURE VII 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 : 1 and 5: 1 . The type G22 `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 100 2 micrometers in the object, 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) Insert 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 adjustment 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) is known and recorded. (d) Place a stage micrometer on the microscope object stage and focus the microscope onto the graduated lines. (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(la). This can be done by using a stage fitted with verniers. (g) Use the following equation : 1 1 --y --. D = d = diameter, to be specified Example : Step (e) produced an object length of a Porton graticule of 180 /xm. Step (f) produced an actural length of 4.50 mm. _ , N 4.50 mm Step ^8' 0.108 mm ,,. , X 0.1 = 4. 17 mm it 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 " Waiton/Beckett's graticule of discdiameter 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 microscpe. (b) Make sure interpupillary distance of eyepieces is set correctly. (c) Note the objective magnification and any intermediate magnification used. (d) Focus the microscope onto the stage micrometer. 67 (c) Line up the eyepiece graticule with the graduated divisions on the micrometer so that the number of whole micrometer divisions can be counted from one side of the eyepiece graticule graduations to the other. (f) If less than a whole division remains, estimate this fraction to the nearest micrometer and add to the number of whole divisions of the stage micrometer after converting to micrometer. This totalled result is the projected or object dimension of the eyepiece graticule. Example ' (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 whole divisions span across the graticule, i. e. 10X10 um. (c) The remainder of the 11th division is estimated as being one third of a whole division, i. e. three um. Adding these together yields 103 um which is the object dimension ot the eyepiece graticule. Note that if the interpupillary distance, objective, intermediate magnification, or even in some microscopes the eyepiece is changed then this usually changes the object dimension of the eyepiece graticulc-thus necessitating recahbration. (1) Available from : Graticules Limited, Sovereign Way, Botany Trading Estate, Kent, Eng'and 1RN, Reference No. G22. (2) Also available from Graticules Limited, but has yet to be assigned a Reference Number. 68 Drawings of Various Asbestos Fibres NOTE: All drawings are the same scale i.e. one micrometer = 1 mm. The number in the ^ right bottom corner of each drawing indicates the number of fibies (as defined) counted. (a) Single fibres These are the simplest of the fibres to identify and count. They are the most common of measurable fibres as seen on the membrane filter. Amosite and crocidolite fibres gener ally assume a straight needle like form. Chrysotile fibres, while sometimes straight, often assume a curved or curly outline. Fibres which appear irregular and perhaps "unfibre like" are counted if they con form to the basic requirements of fibre definition. ANNAXURE-VM (b) Split fibres These appear generally as a fibre or splitting away from a single stem. i'c) 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 he nearly parallel and appear to originate from the same bundle. 5pm A Y rY r. i c , i i F !i 1 ' fi Y I 11 1 i i i 1 O o N p R a i 1, Y 0 Scoie 5pm A !B C D Y % li A Y 2 4 3 4 2 G H K L 1 l|\ ^ 1 0 0 0 0 Scale (d) Fibres with other particles A This group consists of fibres attached to, or embedded in particulate matter This latter material could be parent asbestos rock, or resins, cement, silicates, etc as used in nianuiacturcd products. Under the microscope some fibre, especially chrysotile, appears to project from the particulate matter with only part of the fibre seen. Other fibres (often amosite) are seen as embedded in the particulate matter. 69 B C ? D E I 0 0 0 Scale i___ i 5pm 0 0 AMNEXURE-IX m e a su r em en t of effctive filter area One convenient way in which .0 determine the area of the dust deposit (U . .1 * ,Ul" area) is as follows : _ (.) place a small quantity of dark coloured fine dust (e.g. carbon, cement or road dustl rnto a to 5-litre container with a lid. (bl Shake the container, remove the lid and draw air through a membrane filter and it. holder until the airborne dust in the container forms an ob.rons depot on the filler. (c) Remove the filter from the holder, and mount onto a microscope slide in the normal manner as described in the standard method. ^ (d) Measure at least four different diameters of the J ^ u h a n t dust spoUo^ wdhm^b^ Amongst other methods, microprojection measurement, o stage verniers have been found satisfactory. (e) Provided that the measured diameters differ by no more than 1 mm, a simple arithmetic (C) average ^sufficient to provide a good estimate of the effective falter d-ametcr . (f) At least three individual filters must be prepared and mean area calculated. (g) Provided that the three filter diameters differ no more than 1 mm, a"^ " tT ^the should be taken and the area calculated in the usual manner. Tins area ,s then Effective Filter Area to be used for calculations in this method. ,,,) If s.epsM or (g) produce d, * . . . greater .h a u l mm, close a,,c,,,lo,, should bo puid u, the sampling of the dust or to the filter clearing technique. U) It is necessary to repeat the measurement of the effective filter area if the type ot filter or holder, or if any aspect relating to filter clearing is changed. (j) It is advisable to repeat the entire measurement procedure every 12. months to ensure t mt the correct effective filter area is known.