Document 4QY52adoJ1p8bM9zpd0oz946x

FILE NAME: Z//E DATE:D DOC#: /E DOCUMENT DESCRIPTION::ZZZ &Z ~ )'"::';___. . , E XIV NUMBER l INDIAN JOURNAL OF ; ' DUSTRIAL MEDICINE Editor : Dr. P. K. Ghosh Asst. Editor: .. C. K. Ramchanclr.rn Business Manager: ,, n. N. I3har ,;. ' "' MARCH, 1968 OFFICl:\L c)RG1\N OF .SOCIETY FOR THE STUDY OF l>IDUSTRl:\L !\!r.D!CI'~E-l',, ;L\ t9,NILMONl-MITTER STREET, CALCUTTA-6 '.fonJ ust Cone. 1 mp/cft.- - - rage & Range 15.7 ),627.2) 17.5 1. 5-23.5) 43.9 3388 1.4-362.3) 5.1 5-.9) 24.7 64.5 16,7-72.3) 11.6 i.8-14.8) tions of -TP) ize ranges 120. ASBESTOSIS IN AN ASBESTOS CEMENT By Dr D. P. l3<111erji* FACTORY Introduction Asbestosis is a pneumoconiosis with pulmonary fibrosis due to the inhalation of asbestos dust. Minerals of fibrous form are Cd lied asbestos. They are silicates of varying composition. In asbestos the silica is combined with such bases as magnesium, iron, calcium, sodium and alumimium. The mode of action of these silicate Justs on lung tissue awl the type of fibrosis produced are quite difh:rent from what is seen in silicosis. The asbestos fibres are 20 to 500 fl in length, and 0.5 to 50 in diameter. The disea'se does not usually appear until J.!t.:r S tu lU ye~rs of expLsure. 5 million particles per cu. ft. of air is the nuximum allowable safe concentration, but recent work suggests that the standHds may vary with the percentage of long particles 1n the dust. Occupational exposure occurs in thuse trades where it is usl<l for packing, insulating or fire-proofing or where it is combine! with cottJn or other materials in textile processes or as~estos cement factories. History Asbestosis is cumparativdy a !lrwn dior<ise. In FJ06, MtJn'.ague- Murray reported the case of an asbestc1s worker who died in EOO ot "typical fibroid phthisis". In 1928 '1eilt: r reported a Cd Se \\ hich seemed definitely to establish the relationship between the inhaltion of asbestos dust, and disabling and fatal fir ros1s. Later 11. 1930, an enquiry was instituted under Merewether and Price throughrJut Great Britain anJ the occupational origin was proved. In ,.\merica in early thirties studies were made by Lanza, Sayers, BlcHJmfidd rnJ <it\icrs reg.nJir1g ;nluLiti,Jn of asbestos dust and pulmonary fibrosis. Medic.il Inspector of l!'dcton~o. B1l.rnr mo INDIAN JOURNAL OF INDUSTRIAL MEDICINE The Study l\i.:purt~ ol \'ar1011s studies cnnduc~ed 1n U.S. A. and European Cl) lfi'.flt'S lm the incid,,nce of as!:i_stos1s in asSestos dust laden working em 1r H1n1cnt are a\'ail.1hle, but no such study has been conducted in India so !Jr. \V1th a view tl get an idea of the incidence of asbestosis in asbestcJs dust Lde!l env1rnrJ1nent in Indian factories, a study was conducted in .:in asbestos cement factory. Here the asbestCJs fibres are tirst ground and then mixed with cement and water for making asbestos cement sheets, pipe>, rid~cs, joints etc. The study C<msisted of investigations on the working environment and medical studies of the workers involved. Process of Manufacture The different processes are given below: 1. AsliestcJs fibre grinding : asbestos of the chrysotile type of different grades obtained from U.S. S. R and Rhodesia are ground in open roller grinding milts. Fibres are fed manually from gunny bags and wc1ter i~ ~prayed on the rollers (upto 13%). Lot of dust is produced in this section. 2. Heating or l\lixing: Portland cement is fed into the beater or IJll\Irlg tank by bucket elevators, grounded asbestos fibres in gunny bJgs are manually feJ 1n the beater tank throcgh an opening at the top in the proportion of 1 : 8. Lot of dust 1s produced in this section. \Vater is ad<led in requisite amount. 3. ~1achine 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 cylinders. 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 fitt10gs, 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. c ' Lot of d1~ So, th asbestos fibn The er centration an manufacturir precepitator and 2 show environment Air born cement factor Operation Grinding Beater House (pouring of a Cement asbest mixing Filing Sawing (with ' extracto1) Sawing (with c extractor) In all the ~llowable conce nd European aden working ucted in Inc!ia Jestosis in asvas conducted e tirst ground estos cement : environment wtile type of re ground in 1 gunny bags f dust is pro- the beater or es in gunny pening at the uced in this mixing tank .sses through :ating cylin- required size j sheets and uated. rayer for 14 ) mature. It ridge fittings lrying of the Hil 8. Filing : the pipes, fittings, ridges and ridge fittings are filed manually with the production uf lot of dust. 9. Sawing: Mechanical Lot of dust is produced. So, the processes 1,2,7,~ asbestos fibres. <'awing is done to cut the sheets to size. and 9 produce lot of dust-containing Environmental Study The environmental study consisted of determination of dust concentration and estimation of particle size in the environment of different manufacturing processes. A series of samples were taken by huth thermal precepitator and midget impinger and the avera~e arrived at. Tables ! and 2 show the dust concentration and the dust particle size in t::e environment of different processes. Table I Airborne dust concentration in various operations in an a~Lesti)s cement factory. Operation Instrument used for sampling. Grinding (a) Midget Impinger (b) Thermal Precipitatot Beater House (pouring of asbestos) Cement asbestos mixing Filing Thermal Precipit;i.tor Thermdi Prccip~idtu1 Midget Impinger Sawing (with dust extractor) (a) Midget Impinger (b) Thermal Precipitatut ,Sawing (with dust extractor) Midget Impinger Dust concem in mp/cft. Average and rarge. -----15 7 (9G-272J 17.5 ()15-235) 43 9 3.5~.s (315.4-3(,2_') 5.1 (-1 15-S <). 21.7 o4 s (5(, 7 72 j1 Ll.fi ~ 8--14 i In all the samples the dust concentration was more than n>.1 ~1mun. allowable concentration (threshold limit values 162 INDIAN JOURNAL OF INDUSTRIAL MEDIOINE Table II :-:,L..: J;,1iiutj,,;, ,,f c11r~;rne dust in the various operationi; of the 3Sb<"stis ccrr"i.t factory. iSumpl1ng irstrument : Thermal Preciptator) ---------------- i\verJge percentage in size ranges (~ r i ;- "j n ~~ c1 n l: :Sh . L1Lri ~! 0.5-5 93.3 5-10 . 45 10-12. 22 AsDt'SluS ;J .urir'g & mixing with cement (BeJter tlo.i:-,e) Cement l'enl111g 94.2 4.6 1.2 96 75 2 45 08 Saw;n <.?; %3 29 0.8 -- --------- ------- -- --- - - - - - - - - - - - - - - - - - - - (~ i...~rn,11 '.11t.d ! iJ,,1str1d: Jiy_~ien1~ts (Houston Texas), 19'>5 :-The rnl\i:n_;m di: ,:uJ~~ C):1:a1'.rJ'_1rn is 5 million particles per cu ft. of air. :\\,) a\J JJl 'J3'~'~ r'f the pHtlL'l!s of airb:>rne dust in the working environ- rn::nt of dd.~rc:Dt JJ,ty pr.)2esses wae within the most vulnerable range of 0.5 to 5 microns. Medical Study The mdical stu :ly c.')nsiste.:l of:- (a' Clinical examination (l.) Splllum e-.aminatiOn (c) \'1tc.l Capacity determination (d) Rad;ological e\arnination of nposed n asbestos dust for long time a selected group of workers The study group consisted of 51 workers (20% sample)-asbestos w,nkns selected frum the pr ice~ses with exposure to asbestos dust. None of theoe workers haJ any history of exposure to any other occupat10nal clust. Age di-;tribution : Table Ill sh 1ws the age distribution of the w,;:kers in th~ sttd; [(r 01up \Lij-,ity of the workers (73%) were in the age group 31 to 5,) years. Table III .'\ge distribution of the workers. Age in 'r\:ars --~-- ------ 30 and less 31 to 4 I 41 to 50 51 and JlJove Number 11 22 14 4 Percentage 21 43 28 8 ASE Duration o of the workers tc majority of the continuously for --------- Length' Less th< 5 to 10 More th Clinical 6 workers under s 30% showed lun showed some te sis with tenden1 Signs at Dyspor Cough Lung c Clubbir Cyanos Sputum e expectoration r _., tion of their s1 ' each and all of Vilal Ca1 D.R. P. und the three din recorded in eac Low valL fownd in 29 ou auived at by aaes. .. _ operation~ of the tor) !ge in size ranges 10 10-12 ~ 5 22 .6 1.2 45 0.8 9 0.8 xas), 19'.>5 :-Tbe per cu ft. of air. working environvulnerable range Doralion 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/o) studied were exposed to asbestos dusc continuously for a period over 5 years. Table IV Period of exposure to asbestos dust. ~------------------- Length of exposure Number Percenta.ge Less than 5 years 5 10 5 to 10 years 27 53 More than 10 years 19 37 Clinical findings: Table V shows the clinical findings of the workers under study. 41% of the study group had dyspnoea, 31% c0ugh. 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 ~endency to right heart failure. roup of workers ample)-asbestos .o asbestos dust. e to any other Table V Clinical signs and syniptoms Signs and symptoms Number Dysponea Cough Lung crepitations Clubbing of fingers Cyanosis 21 16 15 3 1 (?) Percentage 41 31 30 5 2 .tribution of the 73%) were in the :entage : 21 43 28 8 Sputum examination; 19 workers amnngst the study gwup h.ld expectoration of some sort during the co11rse of the st idy and namir'ation of their sputum showed the presence of typical asbt:stos h,clies in each and all of them. Vital Capacily Determination: To measure the ;i'. 1 capanty, a D. R. P. und Auslando patente fi.e;d spirometer was used. Highest of the three direct readings made in the rn::.irnin.; with worker stanJing w:is recorded in each case. Low v0 lues of vital capacity at BTPS (less than 7{% predickd) \\.t're found in 29 out of 51 asb~stos workers i e. 28% as compared to the norm arrived at by Rao et al i e. 3.60 litres B. T. P. S. for !ndian m1lcs of "l'. ages. 4 lti4 INDIAN ;JOURNAL OP INDOSTBIAL KBDI011'B Radiological Examination : radiologically examined for the 49 workers of the 51 under atudy were the positive X'ray findings chest. Table VI ahowa the llhftlna?Y of Table VI Radiological findings. Type Number - - - - - - - - - - - - - - - - - - - - - - General haziness of the lung fields Fine mottling of the lung fields particularly in the lower zones 3 6 -Co-ars-e gr-a-nu--lar-m--o-tt-l-ing of lung fields and beyond the lower zones 4 ings. 13 out of 49 (27%) workers x'rayed In 3 cases there was genera had positive radiological find- sort of ground glass l haziness of the lung fields appearance. In 6 cases there was aiving some lung fields beyond while in 4 the mottlings were of coarser fine mottling of type and spread the lower zone but the apices were free. cases, there was some cardiac enlargem In addition in two sweaesn diente4ctceadsersa.dioNloJgcicasa.l~lyo.f carcinona eonft.lunSgcsaottrarpeudlmcaolncaifriyedtusbpeortcsulwoesrise Discn11ion Estimation of airborne dust the factory showed that it was concentration at different aectiona of allowable concentration several times higher than the maximum (threshold limit values) of 5 millio cu. ft. of air of the working atmosphere. n particles per The determination of particle sinizgeaatlmsoossphhoewreedwatshawt iothveinr 9th3%e raonfgtehe particles encountered in the work- tially harmful to the lung. . of 0.5 to S microns, which ie poten Majority of the workers ---------- under study (90%) were continu exposed to asbestos dust for a period of five years and more. ously About 28% of the workers than 74% of the standard value under study showed vital capacity Jen litres. The diminished vital for Indian capacity was males at B. T. P. S. Le. 5.60 corroborated by clinical i ngs. 41 ';lo complained of dyspnoea, 3 l % cough with find expectoration, bwahsialel r3e)g%ionw. heOnnelxya4mcinaseeds sshho'Jwweedd l(u7%ng) schreopwitationa particularly at the bing ; there was cyanosis in one case. ed some tendency to clu~ All the 19 cases with expectoration indicating that asbestos dust was showed typical asbest_o bodies, for sufficient period of time. being inhaled and retained in the luop Al ::::.N.aiologi The auth 'the industry anc 11 Station, Ohanba Sri A. N. Sin: ance in the worl kindly reviewed Merewetber & Co. (Pul: Hun. De . Uoivmity P McOOnald,f 1025, 1927. 4. Knox. J. F 10, 23. . ~~,~ Lanze. /\.. J. t~ d ." ~"6. Pendergrass ~~- ~. Univtttity I K ''7. Maxey, Century-Cro nder study were the summary of Number 3 nes 6 er zones 4 :liological findls Kiving some ine mottling of >e and spread !dition in two ied spots were y tuberculosis 1t sections of he maximum 1 particles per on of particle in the work1ich is poten continuously capacity less S. i. e. 3.60 :linical findpectoration, ldrly at the cy to club- stos bodies, n the lungs Radiological findings confirmed the clinical signs an<l 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 inci<lence of asLestosis amongst workers, if any in an environment with asbestos dust. Working environment contained dust particles above tht! maximum allowable concentration for asbestos dust and of potenti.1lly harmful particle size. 30% of the workers under study, who had exposure t11 the cL.ist for .5 years or more showed clinical signs and symtoms of asbest,Jsi,;; vhile in 26% the clinical findings were corroborateJ with both r<1Jiolog1cal fi 1Jings and lowered vital capacity. Acknowledgement The author acknowledges with thanks the Cocperation given by the industry and workers in the study and the Central \lining Resea:ch Station, Dhanbad for helping with the dust analysis. Lastly, he is grateful to Sri A. N. Singh, Chief Inspector of Factories, Bihar for constant gl:id- ance in the work and for permission to real this paper. Dr. J. Singh kindly reviewed the chest roentgenograms. References 1. Merewether, E. R. A., Industrial Medicine and Hygiene, Butter'.\ _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, 13m. \1. J. 2 ; 1025, 1927. 4. Knox, J. F. and Beathe, J. (1954), A. M. :\. Arch. Indust. Hnin~. 10, 23. 5. Lanze. A. J., Asbestosis, J. A. M. A. ; 106: 368 (Feb), 1936. 6. Pendergrass, E. P.: Silicosis and Asbestosis, New York. l'J3~. Ox'.orJ University Press. 7. Maxey, K. F., Preventive Medicine and Public Health, AppleonCentury-Crofts. Inc., New York, 1956. 166 INDIAN lOURNAL OF INDeUdSiTciRnIeALan.MdEDInIOdiuNsit!rial Hygiene, 8. Jhonstone, R. T .. Occupatinal M Henry Kimpton, London. and Sita Devi, A., Physiolo- 9. Rao, M. N., Sen Gupta, A., Saha, ry P. N. Capacities in Health (ICMR special gical Norms in Indians, Pulmona 10. SMereiersewReetphoerrt, EN.oR, .38A).. 'Memorandum on Asbestosis', Tubercle. Nov. Dec, 1933. S. C., and Kerley, P. (edited by}, 11. Shanks. 2), Lewis, London, 1950. Text Book of X'ray diagno- sis (Vol. 1 for a ; which The irr known earlier: years ti dust its rise to Corcora I, Wl silica o pathog1 sent in 1948). from th on the, also be nary afi more p are exp T chest ra materia radiolog inhalati1 there n higher 1 usually has bee casea o con1os1 c little c 166 INDIAN JOURNAL OF INDUSTRIAL MEDIOiN! 8. Jhonstone, R. T .. Occupatinal Medicine and Industrial Hygiene, Henry Kimpton, London. 9. 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. Dec, 1933. 1 11. Shanks, S. C., and Kerley, P. (edited by), Text Book of X'ray diagnosis (Vol. 2), Lewis, London, 1950. for a : which The irr known earlier years ti dust its rise to Corcora WI silica o p a t hog{ sent in 1948). from th on the alBO be nary afi more p are exp T chest ra materia radio log inhalati1 there n higher r usually has bee1 cases of coniosis On little or "Oen