Document JNn70oRMqBE1q98L7Gd1k9zaO

FILE NAME: Asbestos in India (IND) DATE: 1968 Mar DOC#: IND001 DOCUMENT DESCRIPTION: Journal Article - Asbestosis in an Asbestos Cement Factory E XIV NUMBER 1 INDIAN JOURNAL OF dustrial medicine Editor : Dr. P. K. Ghosh Asst. Editor : ,, C. K. Ramchandran Business M anager: ,, B. N. Bhar MARCH, 1968 r, { JA\ OFFICIAL ORGAN OF SOCIETY FOR THE STUDY OF INDUSTRIAL Mr-DICINE_1\, :IA 19, Nilmoni Witter Street. Calcutta-6 ASBESTOSIS IN AN ASBESTOS CEMENT By Dr D. P. Banerji* FACTORY Introduction Asbestosis is a pneumoconiosis with pulmonary fibrosis due to the inhalation of asbestos dust. Minerals of fibrous form are called asbestos. They are silicates of varying composition. In asbestos the silica is com bined with such bases as magnesium, iron, calcium, sodium and alumimium. The mode of action of these silicate dusts on lung tissue and the type of fibrosis produced are quite different from what is seen in silicosis. The asbestos fibres are 20 to 500 /i in length, and 0.5 to 50 in diameter. The disease does not usually appear until alter 5 to 10 years of exposure. 5 million particles per cu. ft. of air is the maximum allowable safe concen tration, but recent work suggests that the standards may vary with the percentage of long particles in the dust. Occupational exposure occurs in those trades where it is used for packing, insulating or fire-proofing or where it is combind with cotton or other materials in textile processes or asoestos cement factories. History Asbestosis is comparatively a newer disease. In 1006, MontagueMurray reported the case of an asbestos worker who died in 1000 of "typical fibroid phthisis". In 1928 Seiler reported a case which seemed definitely to establish the relationship between the inhaition of asbestos dust, and disabling and fatal fil rosis. Later m 1930, an enquiry was insti tuted under Merewether and Price throughout Great Britain and the occupational origin was proved. In America in early thirties studies were made by Lanza, Sayers, Bloomfield and others regarding inhalation of asbestos dust and pulmonary fibrosis. * Medical Inspector of factories, Bihur ItiO INDIAN JOURNAL OP INDUSTRIAL MEDICINE Ib e Study R.epuf ta of .var.ious -studi conducted iinn UU.. oS.. AA.. and European co mines on the incidence oi asbestosis in asbestos dust laden working environment are available, but no such study has been conducted in India so tar. With a view to get an idea of the incidence of asbestosis m as bestos dust laden env.ronment in Indian factories, a study was conducted m an asbestos cement factory. Here the asbestos fibres are first ground "d m '" d, wi,h " TM"> "d for making asbestos cement sheets, pipes, ridges, joints etc. The study consisted of investigations on the working environment and medical studies of the workers involved. Process of Manufacture The different processes are given below : 1' Ashcstos fihre grinding: asbestos of the chrysotile type of different grades obtained from U. S. S. R and Rhodesia are ground in open roller grinding mills. Fibres are fed manually from gunny bags and water is sprayed on the rollers (upto 13%). Lot of dust is pro duced in this section. 2. beating or Mixing : Portland cement is fed into the beater or mixing tank by bucket elevators, grounded asbestos fibres in gunny bags are manually fed in the beater tank through an opening at the top in the proportion of 1 : 8. Lot of dust is produced in this section. Water is added in requisite amount. 3. Machine section : The slurry thus formed in the mixing tank goes to the stock chest through pipes and from there it passes through presses and spreads over in layers on felt fixed on rotating cylin ders. The rolls are formed in the shape of green sheets. 4. Corrugation Section : The green sheet is cut in required size and thickness and carried manually on steel corrugated sheets and pressed by another such to give the required shape. 5. Stripping : after 8 to 12 hours the sheets are separated. 6. Maturing : the sheets are kept under water sprayer for 14 days. The water is then stopped and kept for 7 days to mature. It is an wet process. 7. Moulding Section : Pipes, pipe fittings, ridges, ridge fittings etc are hand moulded. Some dust is produced due to drying of the left overs of the materials on the floor. 8. I manually 9. S Lot of du So, th asbestos fibrt The er centration an manufacture precepitator and 2 show environment i Airborn cement factor I Operation Grinding Beater House (pouring of a Cement asbest mixing Filing Sawing (with ( extractor) Sawing (with extractor) In all the allowable conce 8 il Filn,g the pipes' fittlngs, ridges and ridge fittings are filed manually with the production uf lot of dust. 9. Sawing : Mechanical sawing is done to cut the sheets to size, Lot of dust is produced. So, the processes 1,2,7,S and 9 produce lot of dust-containing asbestos fibres. --- - omuy The environmental study consisted of determination of dust con centration and esmation of particle size in the environment of different manufacturing processes. A series of samples we.e taken by both t|iermal precepitator and midget impinger and the average arrived at Tables i and 2 show the dust concentration and the dust particle size in toe environment of different processes. Table I Airborne dust concentration in various operations in an asbestos cement factory. Operation Instrument used for sampling. Dust concent in mp/cft. Average and large. Grinding (a) Midget Impinger (b) Thermal Precipitator Beater House (pouring of asbestos) Cement asbestos mixing Filing Thermal Precipitator Thermal Preciptiatoi Midget Impinger Sawing (with dust extractor) . (a) Midget Impinger (b) Thermal Precipitato! .Sawing (with dust extractor) Midget Impinger 15 7 (9 6 - 2 7 2) 17.5 <11 5 -2 3 5) 43 9 3 TVS (315.4 --362.3 5.1 (1 15-5 9; 21.7 64 5 (56 7 72 5i 11.6 5 8--14 8 In all the samples the dust concentration was more than m.x.mun allowable concentration (threshold limit values' ' 162 INDIAN JOURNAL OP INDUSTRIAL MEDICINE AS! Table II diN'iii'uti'>:i .,f airborne dust in the various operations of the asbestos cerrmt factory. !Sampling irstrument : Thermal Preciptator) Duration o of the workers tc majority of the continuously for O pc rat ions A verage percentage in size ranges Gii rJ ng and Sh , elhng Asoestus p .urit'g & mixii (Beater House) Cement heeding Sawing 0.5 --5 93.3 t 94.2 96 75 96 3 5-10 u 4 5 4.6 2 45 29 10-12 n 22 1.2 08 0.8 Length Less thi 5 to 10 More t'n G >v,-rnni :ntu! ! i J listria 1 Hygienists (Houston Texas), 1955 T h e rrunmum all ,.vaTc conceniratnn is 5 million particles per cu ft. of air. Clinical fi Ai S j a o jj t d3 ,0 of the particles of airborne dust in the working environ workers under s ment of diTerem da.ty processes were within the most vulnerable range 30% showed lun of 0.5 to 5 microns. S' showed some te Medical Study sis with tendeni The meiical study consisted of :-- (a' Cl tnicai examination (L; Sputum examination (c) Vital Capacity determination (d) Radiological examination of a selected group of workers exposed to asbestos dust for long time The study group consisted of 51 workers (20% sample)--asbestos workers selected from the processes with exposure to asbestos dust. None of the.-e workers had any history of exposure to any other occupational dust. Age distribution : t aille III shows the age distribution of the workers m the study group Ylajvity of the workers (73%) were in the age group 31 to 50 yeats. Table III Age distribution of the workers. Age in Years 30 and less 31 to 4 h 41 to 50 51 and above Number 11 22 14 4 Percentage 21 43 28 8 Signs at Dyspor Cough Lung c Clubbii Cyanos Sputum e expectoration i tion of their si each and all of Vital Caj D. R. P. und the three dire recorded in eac Low vah found in 29 ou arrived at by ages. 4 0r / operations of the tor) :ge in size ranges 10 n 10 --12 n 5 22 .6 1.2 45 0 8 9 0.8 xas), 1955 The per cu ft. of air. vorking environvulnerable range roup of workers ample)--asbestos .o asbestos dust, e to any other .tribution of the 73%) were in the :entage 21 43 28 8 Dnration of exposure : Table IV shows the duration of exposure of the workers to asbestos dust in working environment. It is found that majority of the workers (90%) studied were exposed to asbestos dust continuously for a period over 5 years. Table IV Period of exposure to asbestos dust. Length of exposure Number Percentage Less than 5 years 5 to 10 years More than 10 years Clinical findings: Table V shows the clinical findings of the workers under study. 41% of the study group had dyspnoea, 31,4 cough. 30% showed lung crepitations particlularly at the basal region, while 5% showed some tendency to clubbing of fingers and one case showed cyano sis with tendency to right heart failure. Table V Clinical signs and symptoms Signs and symptoms Number Dysponea Cough Lung crepitations Clubbing of fingers Cyanosis 21 16 15 3 1 (?) Percentage 41 31 30 5 2 Sputum examination ; 19 workers amongst the study group had expectoration of some sort during the course of the st idy and examina tion of their sputum showed the presence of typical asbestos bodies in each and all of them. Vital Capacity Determination : To measure the vit ! capacity, a D. R. P. und Auslando patente field spirometer was used. Highest of the three direct readings made in the morning with worker standing was recorded in each case. Low values of vital capacity at BTPS (less than 74% predicted) were found in 29 out of 51 asbestos workers i e. 28% as compared to the norm arrived at by Rao et al i e, 3.6U litres B. T. P. S. ior Indian miles of ail ages. 154 INDIAN JOURNAL OR INDUSTRIAL MEDICINE j- Radi<;;08iCaI Esaminatin : 49 workers of the 51 under study were radiologically examined for the chest T a k U V f u . U y Were 1* positive X'ray finding ' T*bU V` h" " lhe <* Table VI Radiological findings. Type Number General haziness of the lung fields Fme mottling of the lung fields p ,,ticulrly in ,he lower zones 6 " granular mtmhng of lung fields and beyond the lower zone. 4 ines V n T Z ^ workers e 'rayed had positive radiologies] find- sort of g r o u n d " Z m ^ ` lung fields while in 4 ,h . beyond the ^ ' l l t *MV " " " fine mottling of ST a Z ^ Z s . ' T c Z Z T c Z " "f'l SCi" `" ' d " ,1:ieed ,P " was detected radiological!,. ** " " bercuioai. Discussion he f a S r i l ^ ^ l l T L s T CT M,UT "-- f tially harmful to the lung. m,Cr n8' Wh,ch P ^ ' Majority of the workers under study (90ft) were r n,, , exposed to asbestos dust for a period of five yearsand more. m,nU U8,y About 28% of the workers under study showed vital ~ . than 74^ of the standard value for Indian L e a a. B. T P f i T ^ htres. The d.mmished vital capacity was corrohn,,t^ u , f* ings. 41% complained of dyspnoea 3 l 0/ m u ^ clinical find* while 30% when examined showed lung creoit p* ^ expCtoration< b a ,l region. O n,, 4 care. sho!Id ^ bing ; there was cyanosis in one case. Z ld 'Z e ^ " '^ V Z y * club* indicadng tha, aaZtoa" ! Z S Z ^ n d for sufficient period of time. ratned in the luoga AI R&diologi |I 3 cases out of i r i d s d Varyinj ' An invest: .tosis amongst w ! H,ii' Working ,,, allowable conct jj particle size. |jf 30% of th. 5 years or more in 26% the clini ings and lowere The autht the industry anc Station. Dhanba to Sri A. N. Sin: ance in the worl kindly reviewed Merewether & Go. (Puk 2. Hunter. Dc University P 13* McDonald,f 1025, 1927. 4. Knox, J. F. 10, 23. Lanze. A. J. Pendergrass m University I x Maxey, K. Century-Cro nder study were the summary of Number 3 nes 6 er zones 4 diological findls giving some ine mottling of ie and spread dition in two ied spots were 7 tuberculosis it sections of he maximum i particles per on of particle in the work`ich is poten- continuously capacity less S. i. e. 3.60 dinical findpectoration, ldrly at the <7 to club stos bodies, n the lungs Radiological findings confirmed the clinical signs and symptoms. 13 cases out of 49 X'rayed (26%) showed the typical mottling of the lung fields of varying degrees. Summary An investigation was conducted to ascertain the incidence of aslestosis amongst workers, if any in an environment with asbestos dust. Working environment contained dust particles above the maximum allowable concentration for asbestos dust and of potentially harmful particle size. 30% of the workers understudy, who had exposure to the dust for 5 years or more showed clinical signs and symtoms of asbestosis ; while in 26% the clinical findings were corroborated with both radiological find ings and lowered vital capacity. Acknowledgement The author acknowledges with thanks the co-operation given by the industry and workers in the study and the Centra! Mining Research Station. Dhanbad for helping with the dust analysis. Lastly, he is grateful to Sri A. N. Singh, Chief Inspector of Factories, Bihar for constant guid ance in the work and for permission to read this paper. Dr. J. Singh kindly reviewed the chest roentgenograms. References 1. Merewether, E. R. A., Industrial Medicine and Hygiene, Butterv, _rth & Co. (Publishers), Ltd., London, 1954. 2. Hunter, Donald, The Diseases of the Occupation, The English University Press, London. 3. McDonald,S.: Histology of Pulmonary Asbestosis, Brit. M. J. 2 . 1025, 1927. 4. Knox, J. F. and Beathe, J. (1954), A. M. A. Arch. Indus:. Hygiene, 10, 23. 5. Lanze. A. J., Asbestosis, J. A. M. A. ; 106 : 368 (Feb), 1936. 6. Pendergrass, E. P. : Silicosis and Asbestosis, New York, 1938, Oxford University Press. 7. Maxey, K. F., Preventive Medicine and Public Health, Apple-on- Century-Crofts. Inc., New York, 1956. INDIAN JOURNAL OF INDUSTRIAL M EDlOtN^ 166 R T Occupatinal Medicine end lndue.ri.1 jhonstone, K. l-. F Henry Krmpton, London. ^^^ ^ Hygiene. pbysiolo. 9. ...... sis (Vol. 2), Lewis, London, INDIAN JOURNAL OF INDUSTRIAL MBDIOiN Jhonstone, R. T., Occupatinal Medicine and Industrial Hygiene, Henry Kimpton, London. Rao, M. N., Sen Gupta. A., Saha, P. N. and Sita Devi, A., Physiolo gical Norms in Indians, Pulmonary Capacities in Health (ICMR special Series Report No, 38). - 10. Merewether, E. R. A. `Memorandum on Asbestosis', Tubercle. Nov.Dee, 1933. 11. Shanks, S. C., and Kerley, P. (edited by), Text Book of X 'ray diagno sis (Vol. 2), Lewis, London, 1950.