Document LgXO7mjMgE4enbENynpL7ggLQ

Merewether/Price 1930 Study Report on Effects of Asbestos Dust on the Lungs, HMS Office n Need to Warn Workers n Health Risk from Insulation Product Use n Asbestos-Related Disease May Result in Death n Invisible Dust a Hazard Merewether/Price 1930 Study Report on Effects of Asbestos Dust on the Lungs, HMS Office P. 15: "There is no doubt but that fibrosisof the type produced by asbestos can of itself lead to complete disablement and to a fatal termination, and this in the absence of a superadded tuberculous infection." [emphasis added] Merewether/Price 1930 Study Report on Effects of Asbestos Dust on the Lungs, HMS Office P. 34: "The emission of a visible dust cloud at a point where exhaust is applied is a clear indication of inadequacy." [emphasis added] Merewether/Price 1930 Study Report on Effects of Asbestos Dust on the Lungs, HMS Office P. 17: "The necessary preventive measures include first, those directed specifically towards the suppression and control of the dust evolved in manufacturing processes, which are examined in Part II of this Report, and secondly, measures directed towards those employed in the industry... They also include the education of the individual, as in other dangerous trades, to a sane appreciation of the risk, and to his personal responsibility in the prevention and suppression of dust. The protection afforded by respirators is only partial, and there is a real danger that the use of them may give a sense of false security." [emphasis added] Merewether/Price 1930 Study Report on Effects of Asbestos Dust on the Lungs, HMS Office P. 31: "The appropriate methods for suppression of dust may only be fully determined when the harmful effects of comparatively low concentrations of asbestos dust are duly appreciated. Very dusty processes will not fail to be recognised, but in processes such as spinning and weaving, in which in other textile trades special methods for dust control are not required, due precautions are also necessary. The asbestos manufacturers are clearly confronted with the necessity of attaining conditions in their industry which will ensure much less dust in the atmosphere than can safely be tolerated in many comparable trades not using asbestos." [emphasis added] HOME OI'FICli . Copyright Reserved REPORT ON EFFECTS OF ASBESTOS DUST ' ON THE LUNGS a ud DUST SUPPRESSION IN THE. ASBESTOS INDUSTRY PART I. PART II. . Occurrence of Pulmonary Fibrosis and ocher Pulmonary Affections in Asbestos Workers Processes giving rise to dust and methods for its suppression .' . BY k E. R. A. MEREWETHER, M.D. .Medical Ir*t*,Cf<v o Ficr'Vir* AND C. W. PRICE II.Kngtnetrms In^pevtnrni Fnan< LONDON: PRINTED AND rt.'EU5HED BY IIIS MAJESTY'S STATIONERY OFEICE. To be purcliared 'IirrriW from II.M. STATIONERY OFFICE at the fo1 lowm" .icdmso: Adastral H*>u*e. London, W.C.2; iro, Grcrjjc Strrc:, Ldmburj::; Vock Strctt. Afrtr.cfiestcr; i, 5*t. Andrew'> Credent, OfduF; tj. Donegal! S.-juan; Wot. n-*ifast; or through any Hooksciicr. 1930 J'rkc l*. til. Net 1 1 It i Cll Report on Effects of Asbestos Dust on the Lungs and Dust Suppression in the Asbestos Industry. part i. THE OCCURRENCE OF PULMONARY FIBROSIS AND OTHER PULMONARY AFFECTIONS IN ASBESTOS WORKERS. 1.--Introduction. This Report is based upon the data obtained in an extensive investigation during the years l'.lgfi and 192'J. The inquiry was initiated by. the Factory Department of the Home OlTice following tiie discovery in February, 1923, of a case of non-tubercular librosis of the lungs in an asbestos worker, of sufficient severity to necessitate treatment in hospital (Seiler's Case'). Prior to this, this Department had knowledge of only two deaths of asbestos workers, about whom there was expert opinion that the inhalation of asbestos dust had at least contributed to, if not raused, the fatal outcome. The first of these, cow referred to as the " Montague Murray Case." occurred in 1900, but ail that :s known concerning it is contained iu the evidence given by Dr. Montague Murray m 1900, before the Departmental Committee ou Compensation for Industrial Diseases-. In this case post mortem examination conlirmed the clinical diagnosis of extensive nou-tubercular pulmonary fibrosis. The second (Cooke s Case1) occurred m 1924. Here, although Cooke1 aud Stuart McDonald1 were of the opinion that the lungs showed a progressive dust fibrosis together with a chronic tuberculous infection, the etiological relationship between the inhalation of asbestos dust and librosis of the lungs would have been strengtheuod bv the absence of a tuberculous infection. Aa early survey of the industry iu 1910-11 by tiie Department did not dis close any evidence of the existence of a serious health iiatard in the industry, but some experiments on animals conducted in 1912 by Professor ,J. M. Beattie of Sheffield Univcrsitv for the Department showed that the inhalation of asbestos dust will cause a mild degree of fibrosis. When, therefore, investigation of Seiler's Case showed that other industrial and infective causes of fibrosis could be definitely excluded, the necessity of deciding whether the supervention of this disease in an asbestos worker was an exceptional occurrence, or evidence of a grave health risk in the industry, was apparent and tiie investigation referred to was undertaken. ' 2.--Effects of Irritant Dust UroN the Lungs. The cost important local effects which may follow the inhalation of dust include puhuunary and bronchial catarrh, asthma, bronchitis, librosis of the lungs, ami secondary changes, such as emphysema, local or diiiuse. These changes iu the lungs, which may be looked upon as a measure of the etlorts of the living tissues to rejiel nr incarcerate the irritant panicles of dust, necessarily causc interference with the general efficiency of the lungs. The impairment of functional capacity may l>e slight or severe, and temporary or permanent, de pending on the variety of dust, and on other factors, such as concentration of dust anu length <>t e.vp'surc. Moreover, individuals whose lungs have been allcctrd as the result of the inhalation of nc dusts, show an increased susceptibility to the supervention of respiratory infectious, such as tidicrculosis or pneumonia. Fibrosis of the lungs is recognised to be the most imiMirtant lesion caused by the inhalation <>t dust, and the proneness of workers with a dust fibrosis to be affected with pulmonary tuberculosis has liecn shown to lie the main cause of tiie increased mortality rate from the latter disease in certain dusty occupa tions. AI With a solitary exception ail those examined were at we;.; on the _ay of "xaminatiou. i * ('Unicoi Linmination and Htuudnni* adoiitc --" lie aature and purpose 01 Hie innuiry were explained to caeli worker whom net pr:posed to examine, individually, and his or her ixt-operatiou ana.r.ed. K..e:i in dividual's previous industrial history, subsequent to ieavir.g tool. \vi: noted in detail. I his was essential in order to exclude, esuecia!'..-. ;..e effect pre vious work iu any of the numerous processes involving exposure to tree silica dust. ami. to a less extent, the effect of other dusts. 5;milar:v, the in dividual's medical history was scrutinised from childhood ottwarts. to determine the physical level on entry into the industry and any su:~:iueni cauiiges. Particular attention was paid to accounts oi pulmcnarv ah-ents. seme of which, like asthma and bronchitis, are common enough amo. gst tiie general population, yet are also non-specific signs of irritation caused - tlie inhalation of dust, whilst otliers. like influenza and pneumonia, arc c-ccus.anally telloweri by a degree of pulmonary fibrosis. War service, if any. was ^c::- into, es'-eciaiiv as to whether there was any history of the worker having iee*. a gas casualty at aay time. The family and personal historv iu respect o' rdmc.xarv tuber culosis was enquired into, and also as to any close association :ch know; cases of this d'sense in friends or relatives. In approaching t:.e ertinent :uL;ect of symptoms-, great care was taken to avoid leading quest:- s. e'pecatilv in eliciting information as to the existence of any uncuc sitar:r.e-,s o: breath. The actual details of the physical examination do nc; e.:.i for comment, inasmuch as they follow-ed the usual lines of a detailed examination of the chest, with observations of the general health and of the cciid:::;n of the upper air passages. Reference must be marie, however, to the standard of r.or.mahty adopted in assessing the state of the lungs. The appraisement ci any departure item the normal necessarily pre-supposes the existence of such a standard. Every clinician has attained, as the result of experience, his ow; clear conception of the normal chest, but it is not often that he finds it necessary to def.ee tins state in so many words, in fact it seems scarcely possible an d: so. and a.ais for Several reasons: the heart and lungs function ellicicr.tlv -- tatiart wide limits of applied strain, and. although vestiges of past disease may e creser.t and apparent on examination, they will lie unimportant ;f they i never tax the organism beyond these limits, are unn-progres-dvc and do nc: predispose :a other disease. Age itself has recognisable effects, but for this reuse:, alone, nr.s chest caDnot be considered abnormal. There is obvious disparity between the standard of pkysicn. fitness required for an air pilot and that required for life insurance at r-tir.ary rates: in dividuals reaching either standard can he classed as " normal.' ye: many attain ing the latter standard have never approached the tenner. Thus, within limits, various gradations of normality may e distir.rmshed. aud corresponding standards constituted without inaccuracy, t.-.e precise status of anv standard being determined by the purpose for which .: is estr.riislted. For the purpose of this enquiry the standard adopted i.us r-'?n that evinced in anv large group of persons living under similar envir m-an:al conditions, apart'from work in dusty occupations, as those of the great: -ting considered. This is neither a high standard nor a v-rv low standard, but :..e average stan dard of normality displayed amongst the industrial population of this country. Rndiiwrnjiliic K.rnminnt'on of th* l.unas. -- In nihf.tic- a carctc. radio graphic examination of the chest was made in manv (Klti) , t-cs. the necessity for -rliicii in investigations into the efforts of dust upon ;i ' lungs i.as been emphasised rcpratvdlv bv various atithoritu-s. It was nut. r. course, leasiblc to obtain technically sufficient radiograms ot all the workers examined, derived as thev were from l.irtnrirs srnltorrd over the country. srmie n district' remote from a radiological mitre. The mode of selection was dictated bv the needs of the situation, with the object of elucidating material Ininas germane to the investigation, e.g., the elucidation of complicating affections, in measuring the I 'A 0 9 extent .mil progress of the lesions and locating the point at which the earliest radiographic signs appear, ami finally as a check upon the human factor presented by the examiner himself. 4.--Results of the Inquiry. To anticipate, examination nT the data collected in this investigation leads to the conclusion that the inhalation of asbestos dust over a period of years results in the development of a serious type of fibrosis of the lungs. Asbestnsis--the Pnlmounrv Fibrnsi* of Asbestos Workers.--It is helpful to visualise fibrosis of the hint's as it occurs in asbestos workers as the slow growth of fibrous tissue (scar tissue) lietweeu the air cells of the lung wherever the in haled dust comes to rest. While new fibrous tissue is lieing laid down like a spider's web. that deposited earlier gradually contracts This fibrous tissue is not only useless as a substitute for the air cells, hut with continued inhalation of the causative dust, by its invasion of new'tcrritorv and consolidation of that already occupied, it gradually, and literally, strangles the essential tissues of the lungs. ' Id common with other essential organ* of the body the lungs have a large reserve of tissue for use in emergencies and to permit of a diminution of functional capacity due to advancing age or disease. For this reason, and because fibrosis of the lungs is essentially a local disease, it is only when the fibrosis progresses to the extent of obliterating this reserve, that undue short ness of breath on any extra effort draws the worker's attention to the fact that his health is Dot what it should lie. The other symptoms of the disease such as cough are equally unassuming, and are readily ascribed to some common and trivial cause. From this point the progress of the disease is more rapid, since it is now encroaching on the remaining sound tissue of the lungs, already only just suffi cient to maintain him in his ordinary daily activities. Ultimately, if no acute respiratory infection has precipitated a fatal termination, a stage is reached when the lnncs can do little more than maintain life, and the shortness of breath becomes extreme. In its maiD clinical features, therefore, the disease resembles silicosis, as might be expected. It differs from silicosis, however, in the mode of distri bution of the fibrous tissue in the lungs, in its more rapid development, in its radiological features, and, there is some reason for believing, in a lessened susceptibility to the supervention of pulmonary tuberculosis, the liability to which disease is so definitely an added hazard in silicosis The Asbestos BoAic*.--In the limits of those exposed to asbestos dust, angular particles derived from nshestos,' and spicules of asbestos" are found on microscopical examination, and also numbers of peculiar bodies described by Cooke and Hill' ami Stuart McDonald1. Thcv are yellowish brown in colour, of elongated, bead-like form, often with bulbous ends. Cooke' and Roodhouse Gloync' indepemlcntlv demonstrated a mineral core in these bodies, evidentiv derived from the asbestos fibre. Stewart and riaddow'* have also demonstrated their presence in the sputum of nshestos workers. These bodies have not been found to occur in nnv other human affection. Thcv have been found in the sputum within a comparatively short time after exposure to asbestos dust, and in the absence of clinical or radiological evidence of pulmonary fibrosis, their presence cannot be taken at present ns indicating anything more than previous inhalation of asbestos dust. The Im-'A. nr.r or Pulmnnnrv Fihro*is in Asbestos Worker' --The extent of the risk to health associated with exposure to asbestos dust under present indus trial renditions nnv now be ronsiderrd in detail. Of the R74 workers of Imlh sexes examined, lOfi were found to have a diffuse fibrosis of the lungs attributable to the inhalation of dust. Ten of these, and one other in which there were earlier signs of the same condition, have been excluded from further consideration, inasmuch that it was felt that previous work in other dusty occupations, such as quarrying, and coal mining, may have been the prime or a contributory factor in the development, of the pulmonary lesions found. * JO Thus, S3 of 303 workers, nr 20 2 per cent shown! ;i definite fibrosis due to asbestos dust. Au addiuon.il 21 were inund wr.ti preclusive signs ot this disease, I'Ut these are gneii an weight in tiic general cm elusions, ulueh arc uenved solely lioi.i examination of the ti3 eases of dciimte unrosis. Of the 133 radiographed, 02 presented radiographic.nl signs of a diffuse fibrosis, and in a further 23 there were suggestive radiological changes not definitely diffuse fibrosis. In 10 of the former group and 3 of the latter the changes were possible referable to rrmr wor<c in other dusty occupations or to other cause, and they arc therefore excluded, leaving 32 cases of fibrosis and 22 with signs suggestive of early changes in the lungs due to asbestos,--sufficient radiological confirmation. What inferences should be drawn from these figures?--Certainly not that 2G.2 per cent, or roughlv 1 iu 4 of these at present exposed to asbestos dust in their daily work have fibrosis of the limes. As mentioned previously the sample examined is loaded with a greater proportion of workers employed 3 years and over than obtains in these sections of the industry at the present time (Tables 1 aDd 2 above), and as shown in T.'.ble 3 below the incidence of librusis increases with th: length of employment. Therefore in order to obtain an approxima tion of the general incidence rate of fibrosis in these sections of the industry a correction must be applied on this account. Applying the rates shown in Table 3 to the figures in Table 1, it appears that the geueral incidence rate of fibrosis of the lungs amongst those cinpiovcd in these sections of the industry is rather less than i in 8, or, excluding those empieved under 5 years, rather less than l in 3. ` Further corrections would have been necessary if the sample had included an undue proportion of workers from the more dusty processes, but this was found not to be the case. Also nc correction is required on account of differing age distribution since, as will be seen later, the incidence of fibrosis is unaffected thereby. Sex has no effect. These general incidence rates are convenient merely as affording a rough indication of the inherent risk associated with exposure to asbestos dust at the present time. They have no permanent value either as an index of the general risk of fibrosis in the industry from year :n year, or as a measure of the risk in any particular factory or group of employees. This must be so since not only will the distribution of workers in toe industry according to process and length of employment vary from year to year in accordance with trade develop ments, but the increasing application of methods for the 'oppression of dust will haTe a cumulative effect in reducing the fibrosis incidence rate in future years. Effects of .1 nc and Length t>f Emplcymeni.--Table 3 shows the distribution of the workers examined according to length of employment, and Table 4 their distribution according to age, together with the incidence rates of fibrosis in each case. Table 3,--Incidence f Fibrv'is rna.lre to Length of Employment. Years Employed. Nucobsr Exsaiced. 0-4 .................. 3-0.................. 10-14 .................. 13-10 .................. tO And over ... Totals ... 0 141 14 51 343 Caeee o/ Fibrosis. Axrtjl gt io ?etrs. >*utnbr. 0 06 i? i: Croup lacideoco per esot. Of Group leu cases 1 of Fibrosis. _ ;? ! !3`S 0t-l 30*0 0-t OO-.I 34-4 344i*-o4 ! | ;| Of '*3see of Fibrosis. Ofl-O 40 * 4 43*3 32*7 * tat 30-1 iI 41*4 J ' Aft Group. Up to 19 ... 10-29 ............ 30-39 ............ 40-49 ................. 30-59 ............ SO and over ... Total* ... 11 Taui.e -I.-- InriJi-ncc or Fiiimste relative to Are. N umber Examined. 23 130 100 47 to 14 363 Cate* of Fibroin. Average ienutfa of employment . to ytari. Number. 0 U 30 31 11 9 93 Group Incidence per cent. _ 9-3 ! 30*0 ' 5*9 37-9 64*3 Of Group 1cm ' of, F"ilrKo*ai*. 3, ! 6-2 0-1 n 3 97 16 0 ot of ribroaia. 8*7 12*2 2 4? 16-9 19*3 *t 7-3 . 13-6 These tables indicate the outstanding importance of length of employment (and hence length of exposure to dust), aud the negligible ejects of age, on the production of fibrosis. Thus age groups 39/39 and 50/59 (Table 4) have incidence rates of 30 per \ I cent, and 37.9 per cent, respectively, not a wide difference, since the groups include workers in various processes exposed to different concentrations or dust. Moreover, the average length of empioynieut in these two groups, exciuding the eases of fibrosis, is almost identical, but considerably less than the average length for all the cases of fibrosis (13.5 years). It appears also from the same Table that no special susceptibility to the development of fibrosis is shown by young persons, unless it is considered that the figure of S.7 years, the average length of employment of the cases of fibrosis in age group 20/29. has been shortened by increased suscept.cility of ages under 20. As, however, the average age of tins group at cases ot fibrosis is 2'J.7 years, and also because the establishment of fibrosis does not necessitate immediate retirement from work, this is largely discounted. Column 4 of Table 4 also shows a general irregularity which, in itself, points strongly to the negligible effects of age in the production of fibrosis. Turning to the effects of length of employment a very different picture is seen. Table 3 shows that after 5 years' exposure, the incidence rate mounts rapidly, and after 10 years increases almost in geometrical progression. Effect of 1 York in ilificrcnt Procures.--There are insuperable difficulties in ascertaining trustworthy figures of the precise incidence of fibrosis amontrs: workers in particular asbestos processes. This is the result of the common practices in the industry of housing many processes in one r-^im, and of workers transferring from one process to another. These two far: rs. the iar.uencc o: dust from neighbouring processes, and prior work in other asbestos processes, operate to obscure the effects due to work in any one process. By distributing the workers, however, according to the process in which each 4 has been longest employed and grouping similar processes trgethcr. it is possible * to draw certain broad conclusions as to the relative effect o; work in different processes. In this way groups were obtained as follows: -- '" (1) Crushing, opening, disintegrating and mixing. (2) Carding. " (3) Spinning, twisting, doubling, plaiting, etc. (4) Insulating mattre's making. ' ' (5) Weaving ami associated processes. (G) Miscellaneous processes aud remaining iiDclaificd workers. The outstanding point In-uught otu in this wav is the relatively verv low incidence rate of fibrosis in group 3 (termed " spinners " for convenience) as compared with each of the other groups. There is sonic indication also that amongst " spinners " the disease takes longer tn develop, btudv of the radio grams. also, reveals further indications confirmatory of this Moreover, estima tions of the dust content of the air in the neighbourhood of these processes and in that of oth.-rs in the various groups show that the evolution of dust in group 3 is also relatively low (Table 5). i1 ' I1 I I1 ji I. |, !. i: 1 ;1 ' ; i j .j ; , 1 ! ; ; t ' : : ' ! I 1 I I ; , 12 in fact| t|10 history, and the medical and radiological features of the cases of fibrosis, together with the results of comparison 01 the dust counts, all con tribute m smiic degree to the view that with comparatively low coucentratiou of dust in the ncighluni !u>od of a process, the resulting cases of fibrosis amongst the workers in iliac process are longer in developing and remain longer in a milder stage. It follows, therefore, that in such cases the rate of accumulation of dust in the lung has not "ready exceeded the rate of elimination, and a further point of great practical importance emerges, namely, that in order to prevent the full development of tiie disease amongst asbestos workers within the space of an average working lifetime, it is uccessnrv to reduce the concentration of dust in the air of the worktooms to a figure below that pertaining to spinning at tiie time over which these cases were exposed. Not only docs group 2 show the lowest incidence of fibrosis, but it forms the largest individual group in these sections of the industry--about one third, Relative Dustiness of Various Asbestos Processes.--tVhile some reference here to the varying amount of dust evolved by the different processes is necessary, . the causation of these differences and methods of suppression of dust are dis- cussed in Part II of this Report. Different asbestos processes Ho cause the evolution of different amounts of dust into the air of the workrooms, ana, under present conditions, the difference betwen the least dustv and the most dustv processes is very pronounced. In some processes the production of asbestos dust is insignificant; in a second group dust is continuously evolved but in relatively low concentration, as in spinning; in a third group the evolution of dust is continuous and in high con centration, as in dry cloth weaving: and in a fourth group much dust is dissi pated in bursts of short duration, as in emptying the fibre from settling chambers by hand into bntrs. Some additional data were obtained by means of a limited number of determinations of the dust content of the air at the breathing level of opera tives engaged in various processes, with the aid of the Owens' Jet Apparatus, The figures in Table 5 which were calculated from some 50 determinations. give a mush idea of the general dustiness of the processes concerned, and also of the effect of localised exhaust ventilation and damping in reducing the concentration of dust in some of them. The counts in other processes arc expressed proportionately to the spinning, plaiting and braiding group, taken as unity. It will be seen from this Table tlint the dustiest processes are opening (with . old fashioned teasers), sieving (with no local exhaust ventilation), and shovelling or otherwise handlin': asbestos fibre, with a comparative figure of 2.24. The heaviest counts of all were found in this group, in sack filling bv hand in a settling chamber. The comparative figure here was ?4. hut the record was dense, with much elumnincr together of tiie dust particles, witli the result that the total dust count arrived at was undoubtedly too low. Next in order is drv cloth weaving without the api'lication of localised exhaust ventilation, with a figure of 1.05. This is undoubtedly a dustv process. and although local exhaust ventilation reduces the count at the breathing level of the weaver, much dust still escapes into the workroom. Weaving cloth wet. not merely damp, reduces the dust count to a remarkable degree. Column Table 5.--Relntiee Dustiness of rarious Processes and Effects of Localised Exhaust Ventilation and Damp Methods in snppr**sina Dust. ftpinmne TWatdine PUmnr. without local OthftM'l entil- tm. iii. lrw-al rent i|. at mo. n Wfinnt Cloth. Bad. D<7. WuLuU lew'll -a h reel i|. o> With locnl venul. at >.. US UVt. Dtr. with local esh<t Wet. f.M ffl) n Mattfcti Making. n l him t l-wfil CVllAIISl ation. Or*.9 *ith ation. m wuh han't aiioo. nn Opcoiec nd handling hhre. without U-al cvl.aiut V-Ot.l. alion. mi i 1-1T 1-0S 1*0S *s 81 i 1-83 *89 55 3-4 # Not* that l*cr* i4** room*. ftol l*ir*l i*>-sl ot the work bceclw*. general ventilation of iho motuen looking work 13 7 for band u c., nr.rro- rate siu.e the fizuie has been ru,..^ by cius : :ro/.: a .iziii v/ur:::g ary cloth loo;;: Main c-- n k;:. ^ itiiLiit -::v prccautious. sucii as exhaust ventilatiou, or dampmz : .Xu 5. ;ar..: lid C.'Jll. t"UGWS QCX : with a figure of 1.S3 (Zee footnote lac. : :>). Ar ic.v.icu y, exhaust vent; muon, ami damning reduces the ficurc cc:. SlfiCTZ^W. _*ui mv tie iltat the ii-i'.ires in columns D aud 10 are too low, since counts r some sucsi Jui v processes, such as buttoning, sewing, and cutting u:. ire ; .ivniabd*. It wiil b-:: observe: ti.a; ..iru.ng. .uihuuz'u e.-- uiiully ici) iiuj.lv process. produced a c.'zipar.-'.: - liz.;re c: only 1.17. Tins is due in pin to partial enclosure of Tver::::,.- parts c: the carding machine. but is mostly the result of the application :a 1 e\::au:: ventilation. Moreover, tiic figure does not take into ace-ant the extremely dusty operation c: stripping. Relative to the ccmpar.-.tr.-e numbers tor the ctber cinlerent processes, the figure of 1 ::r spirmirz. p.aitir.z and braiding is probably rather too high, owing to contamination oy oust from neighbouring aud more dusty processes. Samples of asrcstis vrrv much iu eli'*n','rnl coujiituttm and physical pro perties, anc the mr:: ina::i varieties, ciirysotiie. crociu- iue. and amositc, the latter two. ::: the cp:ni:a r: experienced workers, usually stive rise to more dust than chrvso'.de in ::xt; 1 -e ir.aaulacturing processes. No evidence was found to indicate t.'.at are ca: of tne taree varieties is more, or less, potent than the others in prrducinz k ro-is. other factors, such a; concentration of dust, being equal. A 'ecuiiantv of tne asbestos fibre is that it arse tragments longi tudinally, and a.-:\:ie.-.:iy this process ran go on indefinitely, since there is no ultimate" fibre contparatTe to a vegetable fibre such as cottcu. Concer.: "it ion o' Dus: can Lcnnth of Exposure Xecrssnrp to Produce Fibrosis.--rr;n the data s^ far examined it seems clear that nbrosis of the lunzs is a definite e:.up.v.ionai risk amongst asbestos workers as a class. Furthermore, it appear.: that the r:sir falls ao't heavily on those longest em ployed aud ca those enzazeci in the more dusty processes. Some further rra-rie: atioa of these two important :at tors, length o: em ployment azu concentration of dust, is desirable. Obviously, to some extent, they are interdepend-.-:-.:, since, assuming that a sr.ecinc quantity of asbestos dust must be inhaled to pr-'dure a zeneraiised fibrosis, the lii>r'v=i5 will result from exposure for a periou of time varyiug with tiie concentration of dust in the air breathea. Siuison ' reports the ..use of an asbestos anil worker in South Africa, exposed for 12 months to a very .iustv atmesnhere. ::<i died idem a rapid tuberculosis: sections c: the k:nz= slewed, apait trot:: the chance: due to tuber culosis, a moderately maraud zurn-us. Burter. and i'r.ze"' report the case of an r.sbestrs siv'mer emuicyed la raoutas. "'no died fn>i:i a zeneraiised tubercuiosi:. i mz-r.tus alter ceasinz w-ork. In this case a little fibrous tissue was genera.lv to i-e seer, surrcumiiug the asbestos fibies louad in the iunz tissue, but there was r.o zross fibrosis. It seems probable, therefore, althonzh further research is v?:y e'sr.ry. that not only is a certain minimal quanutv of the dust required mr tho production of a generalised bbtc-is. but that inhala tion of the .rest iuzr. concentration results in the production of a more marked degree of ferosis m a snorter tune, than when the concentration is low. Investi-zatiou of tais important matter--concentration of dust and lenzth of exposure nccc-'arv to produce hfirosis--from the clinical side is beset with difficulties, one >: most nmiusni'z being tliat the e\i>iom-e of a clinically reCOgnisac'e .11iT::: ni-n i- quite cnuipatibic with continued work in the inriustrv, arid, there: re. the ca-cs m fibrosis din overed m -m il an investigation as tliii'.ire in varii.u= -!.:Z'-~ the disease, with the :c-ult llut the point at which they first uccame rcv'-guisabie clinically cannot lie ascertained. Despite this. s.>-;:.. cnniirmatinn of the livimtliesis that the length of ex posure to a.-bostos ho-t in.icss.iry to produce Imrosis varies inverselv with i],e concentration of the dust m the air, within certain low and high limits, may he obtained. mi A 7 1-i Table G shows the average ag: and :: f-: fibrosis in the groups or processes p: eviouily -dea.: wurtt Tanan C. ; of the ruses of ;; . 1. Crushing, op*otm:. disitucgrruim;, mix:;.: 2. Carci.r.s .. . 3. Spinr.inc. i-.nstim:, uoublioc, pliitmr. L: 4. Mattrsss tn.^kinc . ... ... 5. **Teav: ng r.nu associMeJ proc-sscs . 6. Miscellaneous processes cod rema.i;;g cUsiiDed worncri. .. . .. . ; ucv- ' Tou . . ... Cases o.` ;.:roti. A';r:;e , ' m'C' i.*er;c< Lr-c-.r. c( E=-.p::;r:cat 43-1 37 3*-'. i; : 43-1 <2-'. :;: The much longer .average pertoJ o: e.r.plcytrtot. t o: t::cases c: fibrosis m group 3 as compared with ::ie ether gtr.r.s -.v;:l net: : There is aiso least exposure to ojs; iu group j. I- *.ic. 12 _tuup a. longer period elapsed before the hi/rosis civeioped. :r :u2.: :: pr-gr-r^ed :e<? rapidly. This is the more apparent if the incider.:e rates c : lacr.G?: workers employed in the processes in group 3 are cen rare : w. Ji the : rrcsroGZ rates fer workers emploved in the more du-tv pr:::sse= ::u.p nsea iz croups 1. '2, -i, 5, taken together. These rates arc set out :n .able " Ta3L 7.-- Comp'trii*.*i between thg iiiuu.1;:; .?::;? /** F-'-r's:: M orders employed in Grouv 3 . `is j and [~c:rr : Rz:cs aman>j;: MVrkers en:i\cy:d ::: J**:.:/ J, 2 V, 5. :i<cn duttV }>r`?rts:*s). {more Iis-13 Z-i-3tz: ou. i-:'. \71 ici 0Tr. -- "33 : * j* - "3 --- : -_ ; ] ^ j :j ]_'!:J v. ~ ' Q /C---J 1 2 " _ 1 i" 'j 1 2 " J 2 Group 3 ... ... Groups !. 2, 4, 5 (:;;ea together^. i ; Ttr ; Icent. 30 ; o ; -- 47 - Oj1 - j per 1 ceo:. <0 j 2 5-0 32 ; 31 *3-7 i1 t\ . ?r: c-;:. z o*: 11 ?:r :*ct. 4 to-4 { 22 45 3 14, : i7 l i: ?-r cfot. 4 6*7 11 ; 54 Group 3 = .rpinn in:, i^mmc, Juu Mine, Groups l, 2. 4. 3 =* X rujJuuj. etc., c pr.r-..tit`tlriex. i n- 3I*J 2v-:ciated prrrruc^. It svill be t-evn that, af fccr *j vc irs' cr.r^v"cr.:. the rr.tts are crasistentiv much higher .mioncst those employed in t::e More -.iu >ty yrn.----'C. jr-.i v;'.cr32S the rate is high In-in about a yc.'.r= on'-vara ' 1;: the runjc ::> *.y p'.c-.C' :-'. it is not until about the lath year ol .:u;.'Mymc:.t > rt ... ::x i in " '-A Oil;*.;. . roccs-os thnt the rate lor the latter becomes nigh. :; n\ tc tiiiit ru.;:. ..'J alter about b sears' enipi"'.meat in the more Hn.ty >- lf.xposuu: to o'nleient ci'iicentralioos e t-.-joliier ' v 1: h tl'.c of the recoguitipn "i the eases ol tii-r-->is it: -w.i^rs c: the c:; =: :.5C. ."Iso afford an exphniatiou uf the videiy .iihc: tug lengths of c 'npiovnu: : of in- dividual cases of fibrosis, which rnnncti :m 3 v<: irs to ove r :io' 'vViuic no definite case of hbie.-is clearly duo to u-be>: s litisl was found] amoivjs*: worirors with less than years exposure, tlie po.si: ility of sudi cases occurr: ;i^' %rith ^cESKiacasi lh exposure-to high concentrations of dust cannot be ruled out. Three cases were found wild j, ;if ami 41 ycan worl; m asbcitoc, respectively, but. m earn liiuio was previous expusure to other dusts jaee p. 19). - Support fur this view is pruviuoJ by (11 froicssor Beattie s experiments previously im-titianed, which demonstrated that tiie lungs or guiuea-pigs ex posed fur 43 and 07 hauls to asbestos oust showed " deimite ceJiular pro liferation, tnongfi not very extensive, and tins is certainly a preliminary stage in the production of librusis"; (tl) smisou s case mentioned above, and his report in the same paper on the lungs oi a guinea-pig exposed by Mavrcgordato to asbestos dust lor UJO hours during a period nt 5(1 days t >n the death of the animal (from causes other than asbestosisi some 33 mouths later, sections of the lungs showed a slight generalised libresis- tu commenting on the amount of fibrosis iouud, lie states that " a comparison between the human cases and the experimental animal showed that the fibrosis was more lapui and extensive in the human cases than in the experimental animal." aud again ' the amount ox fibrosis-in two of the human eases was quite rapid, and if cue to the presence of asbestos dust, the initial rate of production w-as rapid when compared with present day nou-inicciive silicosis on the liana (3) data iron; tins investi gation. 'n which dl of the 3b3 workers showed signs suggestive of commencing hbrosis (p. 10). Ut these id had been employed tor less than 7 years, and C, for between 4 and 5 years. . To sum up, therefore, it appears probable that cnaeeutration of dust and length of exposure as lactors m the production of fibrosis are interdependent within certain limits. While it seems necessary tor the production of generalised fibrosis of the lungs that a definite minimal quantity ot dust must be inhaled, the lower the concentration of dust m the air breathed, the longer the lapse of.time before the librusis is fully developed, aud within a certain limit, the higher the'concentration of dust, the s'-orter the hbrosis becomes fuiiy developed and the more intense the involvement of the iung tissue. If this hypothesis is correct, and the evidence points to it. the practical inferences are of very great importance, since it follows that the application of measures resulting m the reduction o: the concentration of dust in tiie air in -the-nefghbourhond of dusty asbestos proces-es will cau-e. firstly a great in crease in the length ot time before workers develop a disabling fibrosis, and secondly, the almost total disappearance of the disease, as the measures for the suppression of dust are periccted. DisaoTement proriueni bp the Atbaiof Fibrosis. -- Regarding the amount of disablement produced bv the development of pulmonary hbrosis in asbestos workers,--for a number of years this is surprisingly slight, even more so than is.gencrally tiie case in sihc"i=. This is partly due to the character of the disease, and panlv to the nature tiie were, which in t!v* majority of these processes docs not involve much physical exertion. The axected person may. and often does, continue at work with occasional intermissions, latterly, due to exacerbations of bronchitis, until the conditicr. is advanced, although he sailers increasing inconveniences from shortness of breath, on exertion. Some times a terminal broncho-pneumonia, or ether acute infection, commences while still-at-work, aud. there is no long period of invalidism. There is no doubt but that fibrosis of the type produced by asl'estos can of itself lead to complete disablement and to a fatal termination, and this in the absence of. a superndderi tuhcrculcus miecticu. tg;.*Particulars have been collected up to tr.e end of 1039 of 10 cases in which an advanced degree of the asl-catos burns;.-, without tuberculosis was llie primary cause ut death. In 9. me cause of death was verified In- post mortem examination and in the Pith, repealed clinical, radiohigmal and -putum ex aminations confirmed the diagnosis. In an flth case. ;v~i niorvein examination slowed that a lobar pnciimiintn had v.;;vr-encd npmi lung-,- already the sent of.a moderate degree of the nsU-stos fibrosis. With one exception, all these deaths occurred in the years 193<-33. The length of exposure to asliestos dust iu these cases varied between 9 and 2-fywrs. MM a l > ! ' : ;' j > ; 1 i ' | | | : ' j . i i .1 'j I ' [ .' " ' i '1 _i - ` '; .[ I J 1i 1G It is nut suju-ested that these few fatalities. hi which tlic cause of death has been vcniic.i !)v strict ompurv, ire any criterion ot the true ehect of tl.e di.-a-e on tiie iiiurtaiiLv mtcs ot asbestos workers. Others are known to have occurred m wimh the existence of the as!ie>tos librosis has been licternuned in life, but no ]io>: mortem cxamiouiou has been possible. Progress and Duration of iif Disease.--The rate of progress and duration of the disease varies within wide limits. With eontinued exposure to high conceatrations of dust, tiie nbrosis inav be fully developed in from 7 to 'J years. and may eau=e death alter uenut l'J rears exposure, exceptionally in a shorter period. 0:: the other hand, with exposure to less concentrations of dust, the period of maturation of the librosis may be extended to la. i'O or fid years, There are 'definite indications, derived from the industrial histories and e.xaciication of workers, that a diminution in the concentratiou of dust in the air breathed, ether bv ciiauttc ot employment iron) a highly dusty process to one less austv, or the eiiect ni methods taken for the suppression ot dust, results in a prolongation of tins period of maturation ot the fibrosis, except in the late stages of the disease. While :his is so, the existence of a clinically re cognisable degree of the asbestos librosis in any individual is an additional aaver:: '"actor in the prospects of recovery from any acute infection of the luncts, sue:: as pneumonia or broncho-pneumonia. Association of tiie Ashestos Fibrosis with Pulmonary Tuberculosis.-- As previously mentioned ip. til. silicosis, the librosis of the lungs due to the inhalation of tree silica dust, has an unhappy association with pulmonary tuberculosis, in that there is a much increased hnlulitv to the supervention of the latter disease amougst silicotics. It is of importance, therefore, both from the point of view- of tiie individual worker, and m its bearing upon the scope of the preventive measure required, to enquire whether there is a similar liabi'.itv attached to the asbestos fibrosis. I: will be remembered that in this investigation tiie examination of workers was restricted to those at work at die tune of tiie examination, and, therefore, a number of advanced eases of fibrosis, and a number of cases of pulmonary " tuberculosis--with or without an asbestos fibrosis m addition--who had either given up work or who were oil work temporarilv, will have been missed. Moreover. tiie supervention of a tuberculous liiic.ction on a lung already the subject of librosis produces an increase in symptoms, previously unnoticed or disregarded. and induces tiie worker to seek medical advice. He is then anpronriatelv advised to give up his fins:v employment, migrates from the in dustrv, and mav or mnv not accep: sanatorium treatment. Thus there tends to be a drift of such eases from the fibrosis producing iudustrv. In fact, during the course of the investigation. intormatioa was obtained of a number of person', previously employ.;,) m asbestos, who were either at home or in sanatoria, suliering from che-t complaints Precise information as to the incidence of pulmonary tuberculosis amongst asbestos workers cannot lie obtained tiierefure. in the ah.-eme ot periodical medical examinations in tiie industry, without prolonged enquiry involving tile search of the records of local sanatoria, tracing workers known to have ceased work in asbestos, and examination of death ccrtuicntcs. and of the sickness records of firms, where tiiese are kept. Nevertheless, with these reservations, the data obtained in this investigation did not ciSvhwe any outstanding susceptibility to pulmonary tuberculosis, either amongst asbestos workers as a class, or amongst the cases of librosis. Sunmum.--Tiie outcome of this investigation is to establish the existence of a definite uccupatinn.il risk in the usiieslus iudustrv This takes the form of a distinct tvpe oi liluosis of the hunts, resembling mIu.-hms in its mam clinical aspects, but dilivriuu trniu that disease iu the iimde of distribution of the fibrous tissue ni the lung'. in its radiological features, in the enhanced rate of development under av.-rug'* conditions m llus conntrv. and as lar as the evidence goes, in a lower suscepl ilnlitv to the supervention <u piilmonaiy tuberculosis.' The asbestos librn-is results from the inhalation oi asbestos dust, the proximate causes being concent rut ion of dust in the air breathed .and length * Tb invWic.il sml c.uliuluiticM JaU ubumud iu Ibm iuvsli^anou will bv )mUi*n*U vltewbor*. ir of exposure to it. Idas the incidence raw cesses ami aiuonust those longest euirv-Aeu. influence on the production ot me disease. me dusty prox h-.c uo apparent 5.--Factors Deteu'.mininc the i'lUsr.vT Rz::;:n:t:on of .ur Asbestos Finnosis. It is of interest to consider why it is th-t mis disease mis :uiy recently attracted notice and cecotue a problem m tlie mmjssry, although asbestos was known to, and worked by me aueieuts. _ Many factor^ contribute t: tms pcsif.on, state dependent on ::tc nature of the disease, some on the pucuemcual expansion u: tae maustry. .tuers oa the advance of medical science. _ While asbestos lias been known and spasm:-.:cally worked for hundreds of years, it is only in the past 4U years or so that it eras e-u-ea cjuiu.c: :.a..y exploited to any extent. Not cnlv that, but it is less than du years since me area: expan sion of the industrv commenced. Even alter a inmtrcr cf years o: steady expan sion, the industry is still comparatively small, aaa tue workers employed in the essentially dusty processes relatively tew. The insidious onset and unobtrusive signs and symptoms of tue disease in its earlier course. it = covert advance by itnperaeptic.e stapes, tts points oi resemblance lattcriv to fibroid mbercuic-iv with which in:c-:a:-ra it is semetimes associated, and the migration jf those ahected :rcm. tne ir,iiu;:ry uave .ail com bined to deiav its recognition as an entity, ana t: obscure tlic causal acent. Knowledce of the effects of spccif.c dusts upon the lung- ha= i;cen greatly extended in the rust 20 vears. hut research ha; aeeu mainlv concerned with the more important and widespread risk associate, with the dusts remaining free silica, and enquiry into the effects of other dusts had to wait upon those investi gations. 6.--pREVEimvE Meastp.es. The necessary preventive measures include, drst. these directed specidcaliy towards the suppress,ou and control of the cusi eve.red :a manuracturmz pro- cesses, which are examined in Part II of this Eepcrt, auu seccu--y, measures directed towards these employed in the industry These Latter include the control oi the disea;; by pericoicni meatcai examina tion of the workers, by which tnose uuf.tted by _;a:tn reasons are prevented from entering the industry, and cases of r.urosis and nuimeuary tu.ercu.osis are detected at the eariiest possible moment. The ultimate an.: ca.y rename test of the effectiveness of the preventive measures adopted :n the ;n .ustry wiii be found in the statistics derived from the recoras o: periodica, nemcai examina tion of the workers. They also include the education or the :e :tvid_al. as .:. .. :r iaanerous trades, to a sane appreciation of the risk, ana :c ais persona; res: :as:b:l::y :a the prevention and suppression oi dust The protection aiiorded by respirators is ::iiy rartmi. rr.d mere is a real danger that the use ot them may give a ^nse :: fa.se security Asbestos cust fioatine in the air contains a majority of partiuies c: the order tm, and unaer. many being only 0.5,. (J9inch) iu sire In prac:: a\ me ciisrsmfor: of constant wear, and duliculty m speem. etc., render workers verv unwilling to use this torn of protection ::r any lennth of time Since, however, a high class respirator will trap a proportion of the larce par ticles which can enter the iunu. thev cannot re said to Ae valueless. out can oniv be recommended as a second line of cetrcce. and not in substitution fnr other preventive measures siHiciticallv diiectea to the control of dust as near as possible to its point of origin. I mlcr very exceptional nn un-maces there mnv dc scope for the use of the rduucnt tvrv of treat:tin:: apparatus. coiunnsint: a mask or helmet witii a long tube, enabling the wearer to breathe pure air from a distance. 7.--The From consideration of the nauuc of ilie pmce-ses in tiic asbestos industry, and other relevant matters, it is left that the .uthmk for preventive measures is ;gocd. That is.to say that in the spaco of a d.cudc. or thereabouts, the effect of 1)11 4 9 IS energetic u, pCcaciuu of preventive measures should be apparent m a great reauc tion iq tiiti lut-ul'-nL'' oi An immediate temp-nary rise in the incidence rate is probnbte. due to tbe accumulated bunugr. p.utiy a leuacv ot liie war ears. but with the passing o: the peak, a steady tali si.uulu Misue. . Much generous assistance has been received from many sources during the course of this investigation: these are gratefully .ickncovledged elsewhere. Special thanks arc due. however, to Dr. E. W. Twininu of Manchester and Dr. N. Tattcrsnll of I..','.is for tiicir inuisp-ns-aule expert assistance in the elucidation of the radiological features, to Dr. W E. Cooke. ProtVs.-ir M. /. Stewart, .inti Dr. Roodhmi'c Gl-eiie. whose researches in the same fiehi are well known, aid to Dr. I. M D Grieve for information from an unpublished studv of a groin of asbestos workers. References. ' ' h\ ' 1. Seiler. H. Eh. 3m. Med. Jnl.. 1928. II. 982. . . 2. Departmental Committee on Compeisatiou for Industrial Diseases. : (a) Miiiiic; oi Evidence, Apuendiees and Index, i'JUT. Cd. 3490, p 127. ` . (4) Report. 1007, Cd. 3195. p. 14. 3. Cooke. W. E.. Br;t. Med. -Jnl.. 1324. II. 147. ' 4. Cooke. W. .. Brit. Med. Jnl. 1'.'27, II, 1024. i. McDonald. Stuart. Ibid, p 1027). :- 6. Badhain, C.. Studies m Industrial Hygiene. Xo. 13. Report of tbe Director- General of Public Health, New South Wales. 1327. 7. Cooke. W. E.. and Hill. C. F., Jnl. Royal Micros. Soe. 1927, 232. 8. Cooke. W E.. Dm. Med. Jnl.. 1329. II. 575. t.u . 9. Gloyne. S. R-.odhoc.se. " Tubercle ", 1929, X. 404 10. Stewart. M. J.. and Haddow. A. C.. Jnl. Path, ar.d Bact., 1929. XXXII 172. 11. Simson. F. W . Brit. Med. Jnl.. 192: I. 855. . - 12. Wood. W. Burton, and Page, D 3.. " Tubercle ". 1930. XI. PART II. Processes Giving R-.se to Drsi avd Methods foe its Sltfress.-on. 1.--Introduction. `. The asbestos industry has developed greatly in re-.ent vears and continues to expand rapidly, mainly because of the demands oi tlie motor, electrical, engineering and budding industries, and of the iuereising attention now pain to tbe insulation ot steam plant to promote fuel ecoii- :::v . Asbestos- produets may, for eonvenience. be divided into seven mi: groups:-- .. Tesiu-s. .- (a\ Yarn and cloth. ... . Non-Tt-l'i' v. [b) Millboard, [inper. asbestos-cement sheets, tiles, and ether build ing materials, sheet material of rubber nr bituminous mixtures contain ing Uslv-tns (r) lii-ul.itnm material- and articles. (/id Hi ake and i luleli linings. ' (<) r.u 1,ii>u and I'Uiitings. f/1 Ashv-tos.covered electric rouductors--electrodes, cables ar.d wiring, nuls fur elertrie machinery. (;/) Miscellaneous, inc luding moulded electrical and other greiris. etc. pome faetiiries make both textile and non-textile goods Fo-eni.'rd " liberired '' asliestos, i.e.. opened or brokeu-tip material in a fine ilock-h-kc ; . 10 eondit.un, is manipulated. unmm-d with other material's, in large quantities in the factories included in groups t-d. [b). ami (e), and to a inucu smaller extent in seme ol the other lactones and workshops. is) Asl'C'tns varn is woven into cloth for insulation tuatlres- coverings. in sulating wrapping'. nitcriug material, fire eurtairis. firc-stnctneriug blankets and fiic-rcsisting clothing Narrower woven material is produced lor belting for conveyors, brake liu:ngs ami insulating tape Some asbestos doth is rubber-proofed for use m the innnutaclurc of steaui packings and jointings. Besides its main use for weaving, asbestos yarn is braided and plaited lor use as packing, ami also tor iiauiatiug tmuciiul. ir-uoU ol jam arc supplied to factories in winch electric cubic or electrodes arc made, and polished thread for the completion of incandescent mantles. (4) Asbestos millboard and paper arc manufactured from ;>uip containing short fibre asbestos, by a wet method, like ordinary millboard aud paper. Asbestos-cement sheets, tiles, gutters, pipes, etc., for ouildmg and similar pur poses are made from v.ct mixtures of i'ortland cement and short fibre asbestos. A synthetic composition sheet is made from a rubber mixing, tor use as jointing. Bituminous mixings containing asbestos arc made for switchboard panelling, and ether mixings for floorings. (c) rbsuiatiou materials lucimie liberized asbestos; " magnesia," so-called containing aoout Id per cent, or hbenzed asbestos and fa per cent, ol magnesia, and other finely divided mixtures composed partly of fiberized asbestos, used as insulating cements or plasters, fiberized asbestos stiffened into thick sheets, like mats, for lining bulkheads of ships; shaped sections ami slab-, moulded from fiberized asbestos or mixtures containing it, or built up of corrugated asbestos paper so as to enclose air cells: mattresses, made of asuestos cloth and filled with fiberized asbestos, magnesia. or other filling. (d) Brake and clutch linings are cbielly prepared from impregnated and heat-treated asbestos cloth, but also from moulded asbestos material. (c) Plaited aod braided asbestos yarn, proofed asbestos cloth aud com position sheet arc uetl in mailing packings anil jcir.tinsrs. (f) Electrodes for welding work are platted with asbestos earn or covered with a paste containing asbestos. Some electric cade aud wiring required to withstand heat arc plaited wuh asbestos yarn; field coils for electric machinery may be wrapped with asbestos tape. (17) Miscellaneous manufactured articles or products, composed wholly or partially of asbestos, ioclurie. in addition to moulded electrical and other goods, asbestos putty and powder, rubber hose plaited with asbestos yarn, and many others. Apart from manufacture, certain work is carried on it; nremises subject to the Factory and fVorkslions Acts, as w-cl! as in other premises, which involves use or manipulation of asbestos or products containing it. The insulating of boilers, pipes, engines, and parts of ships is the most important. Much of dais work is done on board ship bv contractors who err.pioy a considerable outdoor S <. 2.--Premises. The factories and workshops included in (a) to to) number at least 100. of which IS are textile factories. This total is bused on iists supplied bv the District Inspectors. It does not include the large number of works where there is incidental use of a>bcstns packing ami jointing, asbestos-covered electric cable, or other finished goods, required for completing other nianiiim lures. There is only one works in which tin; employees rrneerned with asbestos exceed 5H0. There are many small premises in which but a t.-w employees, in some cases only one or two. are employed. A small " asbestos " department is found in a number of important factories. Textile departments me ii'iiallv well housed in mouVru A,,Mings .V few of the older textile factories have been improved icci-iuiy by llio addition of modern buildings. In one ease a badly housed small concern is in process of removal to newly constructed premises. The asbestos-cement sheet faetnries are modern premises of large fkior area, lofty and spacious, in the main, single storey buddings. The cable and electrode tactorics are- also modern nnd generally suitable. S-.rnc v:'w... c: ivj. aorc ;\v ! - ` - :r.--'c engaccc: i bode r com- posi r.u: u .s.itis:.* A:---, a . j\v :o ::.jre u;.'e:i-5icc aicu:. auen pi causes aie .1--; .re!! .v. rr. i are c : : a .til :t nmi stocks materia.. lb: 5 may resu :rn::: ; ::...equ..:e r - tensiiui.irv lu 0:1 1;. the demenu. but .. i. . J duat uvulvoi in iti.ttiUiacturic r IU0` C*SSis is r r: c -iilicu.t :: ;o;.::.* 1;;. 2 realises arc ui: uitaide. ::articu.:r:v i: erov\ 1; 1L : 'ar.t or Valeria;. C rcaui a; is not eusii .' accunipnsiiud ana the dust :s mere ;::.ccn:ra: ; a. Vim:'. :t ..--The ,:r:t::r 1-rvrirri far vcr. I;t:;vasbestos forks var as ir* 0;....r muJit: ,.i. U.: = ;:s?ci. eaect a v ensuie ot z -:ce:r.. ^ A - :.;ucr 01 vorKroofMS v. ic.wie lactoii-;:s are voc: batco b vena::: -dicias. .0 ar: so. oiv Kmiv.' w.-.- -.cm :n v.'iQtcr. 0 ver- head extra;:: pr,;v.\ : La . usci u;vr a: : -uj LG UtlSU tt.tble. In c::e rr.avrt rvr.t cx: ract. a ; ar.s connected : ; l.t: ae overhead auoui are ;:seci. h >.'.rare:?" ; do vniv;uci 1. -.-ment. the .1:v bemu 'jrawn t:V0U2U open :rns in ::..e ileor, t : near ::: :vci. ::;ts r.ot been :::Ct tvith. but h.t s been cocs;verec ::;r some v ; - v; a r rr 'ins t; svstom. i: .es-.nne.l "t a cn racitv su;r.. _*cr cr.-il veil' il.it ! : r.-^ahl tend to reduce the cins: :r. ;b ; z?::er:;l a ; at ; rent VO'l ievt.-i. .1 in. . -it:: other sale. aards. be 2 nossuxe * :er:;u::v? : ? i;ra:> :d ca avji;t vcniiiatji'n it couid not be itrecess- i'ul ~:::hcu; c `.inn. O'-V;:.z f tiio rapid ohai:i: air entailed. Sepcrr.:: 0; --Ir. va vies .even! : : nr? carrie.:. on in the ;:nme r?c: Ir. :: : ab' v.;e ::; 0 e;::-. e menus n( : :vorvrr csca.pc ; : dust in;: the a:r. v.ttiv -vor.; are s:: ojo;; eJ : : n risk frrrr. vine:', tv*' wouic ether- he :~.;v, :r ; a 2:rater r 13 : ;na n th.tt nrisirr tro::: t.acir ow work. Inn few ;ex:::.e factor::;$ cru.5r.1n an- ar-::tins plants are placed close to sn: m n i r; c: ar.d cardir.r r.acii::;:s. j % ? * a.v.e ; arc install'.-- close to loons a: d wet and dr*-' .'xv -;r.r are :a rriea 'r. r '.O.'C 1:orr:iter. In no:.-; cxrii-j premises mere is mere edettir-:i separat:::a 0; uusty \rc rot a::c processes >:u r.on-austv. 3 --DEicntr? :o.v of ?.-. ocr s i;.' *.xn Pi-.event:v z Miasches . A crm.'.k ve a '; *ua: 0: acta r:::r nu-tiioils is r. atter.-.ntcd. Atti;nticn is maic.v x.r-jetc ; :* ttte 'lust-prou pracei-ses. .1 sert;-.::c:i 01 w.tien. in triad oil::::::, has be. 1 deemed nece-s.'.rv to make dear the -t'.rcumslnacr.s under wb:ch exp'vre to d' :.-t ar:-e = and the character ar... ob'.-et a; the remedial measures w.uiy 12 _ :? or her? rcc'f.tr.euded. Sorr.e'-v;. irr.rcr; urs re cr. foot whirl:. :;uadentiv hoped, tt: 1] ^ren:,'.' reduce : tnn-r.re : . in cert.tttt i nroce.'ics. On .ievei'rmor.ti. : n . speeding u:> r; textile stathmerv. a.;i the 1:. varftts tndusu problem. sf adequate aramres to : ; vrttli ti'.e dust :nav ititensiiV me dust not taken. 1nxr.nns. (ai Yam. nnd CloUt. The n-ar::u;a;;u re of rsbes: as v;: rn .;t:J clotli prei :-X n 11 :i>.e whole kke t: 0: otiicr te:a ;ac;. a u': tiicr: arc 'Hfa. ::;:p'.:tant dtuere:: C-. ihherircd ;::;ci ot: asocstci :rater:.:! > tie-aiy a.ua . ed in various iti .;a:hcr; '* was;-:." _:i.i :n tvim:.:, ^.xp* '.ire. in sonic u-. c -ce. t? asbestc; dust. centner, la,r?>rai. nil ;Lc :a; ion; '. but steps have . rn t akea. extec...in; c many yr.ir - tn dc.-r. vilii '1!K :m ' at various p 0 lit - taoueii the r.CLtfSX' CC'CI'CC of ' `:v.tca< v :; va::c"-: iiv ? :.:h:::U. nut been r. ' H I 1'lxiiaU' ; vent; von par:.;; used V : be-;-''na iip\ i asA.-stns favtori" [nr ; o'llOVKl^ 1 i;: '* ;i fa!' to be a> ca' icut a :a ot J r :r\tilc iiulnstr: nun to have be.": .\(ini ever a "'! v tic' : As m*u *r sa.'rtninrds -I. i-t. e.o.. si: -:uu; o:` ntt*- .. .! X t-v i-a: M i -V>. -1; mi lvdlnu il"' nil- :u:-s in pr.;; i: ru:;. ^rer:iti^:v ctli-ac:-: .ncM-itire rt' ui.r amics, ami vacuum nielli oils ot uiea:.:1 * ' 3 * N* *1 Ccvcb'p-t,-.: ;t has 'a made. 0;cni nn.--Ash -tn. silit.il .1c or yarn, has usually to 1 'c rrushed. a :ul in cnscs ** un'fl * (*' ! 111- r 1 " > I KT t ore it is trade inr ': :i rd in;. These prepa torv prac:C< nrc r ic'i led bv 11 inch invrv. but entail mi nil li.iiulivnrk tH`par ing (t* rc*! nvc \ rrD) and trrtiil 1 tt r iieviiio follow crush but jircceiie upcnii T 21 Maten.,1 for vain is not usually treated in disintegrators. lm: in most lotteries these arc u-ed for linen,ting waste asbestos etc. Crushing flattens out am: In . ahs up the mineral n il hunt damaging me ! res. it is accom plished either ;n a lure- c'ce runner, or in a small pan null eu the mortar mixing type. The material is emptied upon the floor clo=e to the nu, nine, tiie contents ot several sacks suincllines luring spread on the floor :o oinaia a rough " mixing." The crushed material is either t.tKcn Iran tiie machine bv hand. or disciiarged through a bottom delivery slide, usually l.iled into sacks or skip.- and. 11 necessary, weighed on a portable weighing uiachine. A lew edge runn:: s discharge upon short inclined lattice' anrl tin: material tails automatically ithe sack or skip. -.Edge ruuners give rise to dust of considerable amount wiierc short hlire is crushed; some are enclosed ami have exhaust applied. 't:.:~ is always neces sary. Pan mills arc not enclosed ami also give rise to dust, though less in amount. Handwork, c.g.. sack emptying and filling, mixing, shovelling and feeding machine pans or lattice feeds, gives rise to dust, sometimes o: considerable amount, and is done without exhaust. Application of exhv.st drauget would be facilitated if feeding were dune from a higher level so liiat sacks might be emptied "''d-w enclosed conditions, i.e. in a sack emptying app trait:.5. Automatic delivery and reversible bagging i iltices eliminate dust pro.iu.ed in hand filling of sacks, but require tn be cihcieiu.lv enclosed with exhaust draught, applied. An open travelling band passing round an electro-:;;.iguet is used for separating loose irou. the asbestos being delivered to an elevator. Enclosed apparatus should he adopted. Enclosed rotary sieves irotaries) or long oscillating irair.e sieves are used for roughlv grading crushed materia!, lhotaries should be mechanically led and the asbestos collected under enclosed conditions mot always done: and exhaust applied to the machine euclosurcs. otherwise unnecessary dust is created, acme oscillat ing sieves are verv open, the material beiug allowed to fail on the floor, and being filled into sacks bv hand. Verv duste conditions are then inevitable. Efficient enclosure with exiiaust draught applied and, to avoid hand filling, automatic delivery and bagging lattices, also enclosed and exhausted, as used in some cases, are generally practicable. Crighton openers, enciosed centrifugal machines, are use.] for opening crushed asbestos, preparatory to carding Careful mixing or blending of crushed material is cllectcd by spreading it cvenh m layers on the dfr over a considerable area--cotton may be added at tins stage if required--aud wne:i feeding, taking a vertical cut through the mass. Admixture with a small pre; trtion of cotton raav also_be achieved by blowing it iuco the feed opening. The opened material is delivered upon a lattice and coiicrtcd either ia a urge ata-mer or in sacks, automatic bagging lattices being used 1:1 some cases, Mcci.-.t.tc.d feeding under enclosed conditions, with exhaust draugat applied to fey:.:.g lattices or other convevors. should be adopted, iiaml iceding gives rise to dust, from sack empty ing, shovelling and particularly mixing mi me floor. Mixing .- a great hindrance to elimination of hand work: it is asserted tiiat poor yarn re-gits 1: it is not dene and that machine mixing lias been tried and gave less sat;-factory results. If retained, it should he done at a higher level than the .:;er. under a large exhausted canopy and the mixture to! at a series of chut:--. Delivery lattices should be well enclosed ami exhaust applied, as now done in 5 me cases; otherwise dust is.evolved. Opened material not required at once, may be stored ::i open bins in the workroom, imolvmg emptying and tilling sacks or skit-, winch uccessartiv cause dust. Tins storage m imik should be avoided; alternative arrangements might lie adopted which avmd dust. . Some material. o.g., Imig fibre waste from later pr- vs5es, is opened at enclosed lattice-led teasers nr will.us. nut infrcqueiuly ot ; asunvc design, worn cut, and emitting much dn-c. lrnfa ithslamling llmt a :.iu :s an integral part of the machine. These old in.niunes should not he used : -r asbestos opening. Dust uiay l-e emittcil at feed pniuts of modern mauidnrs. particularly when the feed is irregular. Exhaust is neev.-sary at the feed lattice fur this reason and also IvcaiiM' feeding itself rau-e* dust. The material is either discharged upon a lattice fur immediate collection, or blown iuto a chamber. The standards suggested for Crighton machines should be adopted. ' ; i' | . . J ; : i. : ' , i ' ( 1 .1 i : ' - . . Hopper lattice lee is ai e largely used with opening machine*. the hui.ticr ups are about 3 lout P inches auovc due; level. Mucli dust is uicduccd siiovei- fceding as it is difficult to avoid s> altering at the lip. An enclosed lattice. led at or just below Hour level.with localised exhaust applied to tiie enclosure is more satisfactory. - _ ... Silicic disintegrntors. or two or three machines in scries ate used tor break ing up textile or other usoesio* u j;;e, more rarely !or opening crusiicd asbestos. Present arrangements for preliminary hand setting ol w.-isto are unsatirtactory: it should be accomplished at a covered bene;:, suitably exhausted, '''ll.areas in some cases, the indraught at the disintegrate.- feed opening* caused by trie rapid rotation of the ioior is not sufficient to letncve dust, and I .cause, at any rate. as soon as it is stopped, escape of dust niav result from reversed air currents, exhaust should be applied hero also. Disintegrated material is bluv.-n into chambers, a blower fan being in some cases connected to the delivery of the machine to create a stronger draught. Air pressure in the chamber is iciicvcu in different ways, the sides niav be covered with sacking, allowing much dust to escape, a " relief baiioou " connected, or exhaust applied. Chambers connected with disintegrating and teasing machines vary in sice, some arc little more than a large box. others are more roomy, home, but not ail. arc separated from the w.'rirrccm They are entered for emiuving, the material being filled into 'arks or 'kins av hand after the machine is stopped or the flow of material diverted to anchor chamber. Work in chambers is verv dusty and its elimination is most desirable. (See page 2b.i Carding.--Considerable developments have taken place m recent years. One or two important new card rectus have been started. Many new macnines, including some ot foreign construction, have been installed. The machines, of large overall dimensions, arc of the roller and clearer type. Modern cards are of high c!a=s construction and fitted with two doner cylinders supported on a carriage, winch can be racked into or out cf position. For fine yarns, a breaker and a limsiier. constituting a :et. is used, connected by Lattices, lap sliver from the former b-iug r.ntoiiiutically led to the nmsher card. la caseswhere tiie sliver is collected iu car.s. a Derby doubler is used :cr prepar- Lag laps for finisher cards. Single machines ami breaker cards are equipped with hopper lattice feeds supplied froui skips or sacks, ii.iuuruis being dropped in. and shaken apart as fed, or the sack emptied luto the hopper. Tae asbestos falls intermittently upon .a creeper feud winch coavevj it :o i.be " k-xer-in " feed rollers, between which point and the doiier the materia! := under enclosed conditions. The material is comberi from the open doners of limsiier cards, as a web or " sheet ", the sheets Irani the two dc:::rs usually being combined at a con denser, anr! the resulting 'liver yam wound iuto spouis. Occasioned-', combed web is collected without being . eiiceuscu. the condcn-rr carriage being v.-ithdrawn. In other earning, tiie <iiv.*r may be obtained as a lap. Admixture with cotton is iisiialiy acccnrpiisiied by carding the ;materials together, a cotton lap being mounted abo; _ the creeper feed, and tlie cotton fed through the Iced tollers with the asbestos The evolution of dust at cards is inevitable and a fine dust ci'ud may be observed in most cardroonis. Suppress;..-:: oi oust r.iiiiiot oe realised unless machines are maintained clean and in satisfactory repair, am! there is effective enclosure of various parts. Above all. .realised exiiaust must bo applied at well-defined points of dust emission. and improved stripping arrangements pro vided. A\'i<ii: spacing of machines is also desirable. The upper parts oi modern m.v iiiiics are usuallv provided with weil made wooden covets and tiie lower juris are enriosed below m metal. The irunies are well enclosed at tiie soles A hinged metal rover, lined in some cases, prevents escape of dust produced Iw movements ot the to.si lattice. A curtain of fabric is less -mi Ufactoiv 1 n older tvpr*. pari irulai iv tiie wooden covers mav not fit satistaeiorilv. the evlindvr* niav i.'t is: irulv aligned with tiv frame and oilier defects niav iirrmuil for ode I'-eau: of dii't. not emit mlhinlc by exhaust. Snell defects 'bonld be remedied. Cieerer feeds. d.ilTers and coiaien-ers and connecting lattires between breaker and finisher cards are not enclosed. Dust is evolved .at duller combs and at creeper feeds. w-- ,.i - y jL 3 Lo-exita ventii.'.t.ou was hist .irt.ieii to .-ar'ting :;s.tc:t:ucs many \enrs ago. Meiii'k au<l n;.--lai-ii buv sil:: beer. gr.usu.iil/ i:n{.rovc*i and more power: u! c\.:. -it dj:i!:."..ts a.-e Low used. Oi.e large Sum have achieved much sucaua by = t.r.:.uarnisi: the:: practice -* regards points ot application of exhaust '.uuug:;: lesigu c: "atr guid'es. ze branch ducts U air guides and duct veicmty. Ex;; ..ust is at tiled at \>i i > oreiicr at the creeper feed. ,i) Iced roller a; hr.-tcr-m. : top OI rvfiuder; pfi eac"h iJi~ie: air guides or hoods being fitted at these ts with c::::iee::t:z branch tucts Mud cnutilinzs. used on branch piueb. f.tviii::m:c e.asv :; i i;. r Br- :h pipe sizes and duct velocities arc liberal T.1:-.- :: rf'-i uv a:~ .yilig puwcriui :Miuuat at eiu.il of the poicts rjunt: jiiecJ. a: :.'A of evou*. ion of dust is in .portant. sliows that this pravice 1 iouiJ L; foil: cri cor.err... v and gives pc: nt to the view expressed ay some < -:uptcrs :::r.i or. ra;r.^ mr. ti earned on prnct:.gaily dust-free. Apart from the arc-.. o case. e>: r.aus: ;s anpJicii nearly ail cases : o tiie cylinders; in a moderate pro' :rt:ou tc tr.e c'eepcr feed: in a lew. to one uoiicr--tr.e top. and in one or two rr.lv. to the bottom doffer But. apart freui dust-emitting points no: provide- for. the results m.av be ir.af.equate. Cnrr.ag manures are occasional!-.- install: i and put ::;t? :;=e without .-xhaast. tins should never be done. Elite ism result? are net pcssm''ic un.'css t he exhaust draught is anpiitd ac closely as possible to the d-.s -producing pom ts Transverse air guides. with braDch darts connected at or - ; end. .ire annnrs more one ; than pyramidal boods of the usual type. D. cts of ,adequate iiameter and high due: velocities are essenttr.i. Tiie usual air guide f: . the cvlinucr. . cvicietl to effect removal of dust both curing card:- r. and : trtprinz and zr: tdinz 'though proved inadequate for stripsir.z) if placed a lit:he .move an npcr.i: z in ib.e crown of the cover. Two branch ducts, ns r.'.ove. and1 in addition a i: rzer centra! branch duct (Tor use durinz stripping: are cor.ziirtec to it. The shallow space below tiie back of the air snide is t'o<d up dunr.z cardiac b - a wooden hir.z-m! piece--thrown back for stripping--and t'r:' dust produced ; : the cviinhe: is prevented from escaping bv infom of air f:cm tiie room, at :he front. The dust-laden air is withdrawn at the side dur:-: To stripping, n.fiow of air rarrvinz some of the strippieg .-ins; takes place rot: below the Ifted eviinder ever: the central branch duct, kept closed bv a blast zate ciur nz carding. is tiicn fully opened to provide a creator air veb me. In cne factcrv. a ; irctilar coder cl nninz brush runs continuously above tiie doner oimh A nvramidai nhatist hood is provided, but much dust escarcs- unio=s :iiv 'fr.oier.t exh.a.i is devised an alternative to this cleaning. i: reni:-.- ncees'e.-. - sk rule! be fou~: . The opllection of combed web. previously referred to. is d-- o w-'t ho;-.: exiiaus; and dust is are.'need Collection roizr.t be effected bv exha.:: st drauzht .as ar died for removing side waste at conaensers. Notwithstanding the - = - of r-.v-s tor re-d iaitire t'ee-is d--.srv conditions are produced and o.xrou't dra-gnt s-mu(| be arr :ed at tins pun: al=n Slnaiat.i c-<-' ' --'nrd " strir-irg " or d,'v':r; i= dope when the machine is er?r- nut for grinding, which follows cleaning and takes place at each machine .akmit once a week, but short-.- and longer intervals a's.-i obtain. In occ important f.a~orv the tw- prrrrs? nr- mm:-ined in on- operation. Holler and dearer rn-e= must be ->nened out. i e.. '..attire feor] -.: ij hreas;. and ron- denser and doiTe- carriages are drawn bark, tiie evlinder covers are raised, and the various small rollers, which are rlrnnc' and ground at - speejai machine, removed Tim r-.-lindcr -1= fir': cleaned. w;;a the n'niTrr marriage drawn hack: the carriage is tl--n repla-mi and tim doiTe-s run at a grow::- increased speed, cleaned in turn 'mining takes about 'en minutes and is usually riom- jn working hours, out in one case, at 'east. after. The men press their " strickles " or flat hand brushes aivmt 1? i:-r'r-"s 'nn; rovereri w;:h carrl clothing. against the wire- covered 'nrf.-nes Much of the debris is : --aw and falls p the door Dust is evolved in a det-se rlund. omr being miiovr-a at the cylinder exhaust hood. Tn one ca'e floor or.yungs Ivneath tiie oi.-icru-e. are connect,j to the exhaust. Precn: rvhansr arrangements arr altogether inadequate, particularly 'O as rezards the I'oti.un dofier Much dust is therefore carried into the general atmo'nhrre of the room The cleaners wear respirators or " helmets." Tn n few i-ases. me-e effective mensu-es are taken, r g,. the npenrd-ont marbine i almost entireiv enelnsed with high canvas-covered sercens. Tn the ( j i ; | | ' I j 1 1 - , ' 24 works where cleaning t::-;:* place after working hours, an auxiliary c.'~-os: system, with a hood lor t:.c uuttom dolicr. ii bicugl.t into u.-e. bunding which Ink.' several hours, is on automatic process :.:ec::g ry abrasive covered rollers -.river, bv the machine. Ihe sniab aincur.: o: oust produced is chiefly of a metallic character. In the factory where grinding ami cleaning ore combined., the dc:.:r ex. oust arrangements are first re- mnecied. Much less dust is evolve: r.:.. .1: rears to be dealt with more cnerttvelv. This firm consider that hand ;tr:c.:..n,_* -::a:e grinding should not be allowed. Their methods may. however, r.a: rer.tra..-' applicable. A little str::.:iiDg may lie nrrrse.irv alter grinding tc remove sma.. pieces of debris. The trade recognise that presen' conditions are uot satistactory and eager.ments are being made w;:a the oi>>cct of developing imprcved .'.npitaa:;;. .r. car case a revolving ni?.!i is ..eing tried, with independent exhaust draaaat apy-lte: by flexible connections; 1; is said to true promise 0; success, it; brasr. ;s narrower than the hand striokic and less dust is evolved at a particular tuement. In another c.ase. a vacuum fitting is under consideration. Previous us; of vacuum stripping was given up treatise of rnimi erosion of the metal pipe beaus ana ether parts. Unless eih'ctive .just suppress>011 is realised ir st: .ppi::tc. t.I we. iters, other than stripper'. shtuid he excluded while it is in progress and far some uu-e afterwards, ami the room wcil ventilated. The machine for cleaning and grinding the 'mailer rd!.:.=. w-tca gives rise to much dust, should be fitted with eliicicut exhaust arm eg 'incuts--a stc'.ie:.:forward matte:--and at rompictclv enclosed as practicable to come t the heavier debris, precautions which are not ak-vavs taken. The machine is ei:..er i.'.stahea in the carding room, or a room adjoining. Independent maciiir.:; shc-IJ be provided to deal with rollers of diilerent lengths, otherwise inconvenient adjust ments. liable to be neglected, have to be made. Card Side IPn-re Trc'-.incni.--The irregular selvedge " of :arde~ fibre. separated at the two sides of the finishing card, being unsuitable fc: sliver yarn. is removed by suction draught to a " side-etui " mactiiue. which pneares it :rr further use. The material is blown upuu perforated cdiiuh.-rs. tr.e air escatrmn at the side ami the material being discharged 011 the tie- r I he prrtsss p: educes dust, particularly when the feeding is irregular, the air then having r. tree nr::', between the cylinders. The material shnui.i be deli'cr-d uuuer suettea r.na net under pressure, a " pressure " machine being unsuitable. Spinninn and --Vain is spun at fiver or ring rr.rr.es w-'r.trn r.ay- carry up to 50 spindles. 40 on each side. Much piecing is rc-iir.reu rwjr.r to the comparative weakness >>: the fibre. A fine metal lb: mid spur. -- :tn ns: estes. for brake linings and certain other purposes. Mule '.-lining ,s net nracttsec 1:1 this country. A large amount m doubling is carried on. Spinning, more particularly ring spinning, giv-s rise to d.:=; ;.::f.r.:.c>Us;y produced bv tiie " bak'oning " out of tiic lihre owing tv rap -- i"..::c:. o: the spindles, which air.v run at pceds or cev-'iiit: us per a::uu:c. r.r.d intermittently, when me varti breaks. Doubling is ie-s eus;-.- ;__g -: ig While the amount bears no comparison with that produced car hug. a:.- is .e.-s than that from dry weaving, the workers are coucimM.usiv ..'xpo-cg :r .or.' cust. more in some factories titan in others, doubtless due to o;;:ere::c-ss ar:.:::: mctlioils or materials Exhaust draught tor its removal a.-- uc: tree:: :en hitherto, but experiments in one tactorv have been so tar sacces-.'... :.ua; :;.e ur.u; arc prepared to cquin .til spinning and doubling frames itii evii.ru-: ve:r:;i_::cm plant, cnil'oilviug (i) exhaust duets parallel with tiic frames. jm? e t:r rgiiers. with shaped iv->1 (< at intervals, each to deal with a small gi -ap of ..cv ,;r.a (ii) for more eiiVcliv" concentration of the draught. pane.-ung tor tr.c ends ami lower parts of the iin-.es beneath the spindles, cnpnn.c o: ivitig .._siiy : erre-e-a wh.cn nccr"arv 5mh safeguards 111.1v require somewhat v.application unless special genera! vent il.it noi is pi touted. W/irpimi.--Whip beams are prepared in tiic usual wav from er.-- iirg fra.-7cs. 1 small evolution o! <lust occurring at the frames and beam: g :i:acs: localised exhaust ventilation could Imrdiv k- .ip|dieii eiTectively. A par:::;caeri- o(! space, mo Itaiii. aliv ventilated crosswise, with extraction at i.w level would eflect improvement. 0S 4'fa a'--Mauv winding machines are used, varying f: in niakcsni; t types of primitive construction. ,il winch the pi notice may obtain ; boiuing tiic yarn in tee hand, to modern universal winders for winding " cheeses. ' Dust may be evolved . -omy extent. particularly in connection with tiic above practice, which cornu bj v..minuted. Application of exhaust draught will then probably not be necessary, except in particular cases. Plait:'..: nr.'- Braidinn.--Plaiting and braiding, also carried on :n engine packing and c!o:tr:c cable factories, and done at machines of normal aesigu. cause sonic evmunnn of dust, except where the yarn is impicgnated with " crease." TVh::: the amount of dust sometimes less than in spinning. the duicreoce is cot material. But there is perhaps less exposure ot the operative under ordinary working conditions and precautionary measures ether than localised exhaust ventilation may sulfice. B'eariaa.--Looms vary greatly in sir.c and general arrangement. As many as 140 looms may be found in a single room, but tins is exceptional. The clear space between machines mav not exceed If inches. Some looms are liiueoendently driven by electric motors. Cotton warp or weft is sometimes used. Thin cloth, lor mattress covers, filters, clothing, etc., is woven from a single warp beam at a simple t'-r-e of loom. Belting 1oot. for thick belting and brake lining material are complicated, several warp beams, arranged in tandem under the loom, or in 'onie other convenient wav. being required. These looms are narrow, but often verv long Tape looms arc also narrow, unless several tapes are woven together when several shuttles, in line, working in unison, ire used. Cloth is beamed a: rhe front in the usual wav, but belting may be led under the loom, and coiled high, above it. at the back. Most weaving is " dry," but some weaving is done wet. either warp or weft, and occasionally both being wetted. TVet weaving accomplished more easily and a closer vp.ovc obtained, but rusting of heald fittings, and the subse quent drving entailed and the less satisfactory anpearanre of the material are disadvantages. Thoroughly dry fabric is required for brake linings and rubber- proofed material, and wet woven cloth may be strongly objected to on this account. ' Considerable evolution of fine dust occurs in dry weaving as a result of la) the forward movement of tiie si.av in " beating up," tb:- source being close to the operative, (b) the repeated contacts of the rising ami failing warn threads with their neighbours, this cource being the most important from a quantitative standpoint, (c) the disturbance of " dust " or " huff " on machine warts. especially those Ln mction. A fine dust cloud mav be observed behind the bc.aiJs above the warp threads. Much less dust is produced in wet weaving. Some " dry " looms are now fitted with localised exhaust usually applied to deal with dust evolved bv both P.d and (A), in some case; ri o:dv. io) A fiat horizontal " hood " is fitted in front of the operative. iu<: above the cloth, tiic opening facing towards the braids; Hi) C'ther an upright pvrnniuial i'.rnri. placed cransvcisriv, or horizontal flat hoods, one on each side fa ing each otiicr. are fitted close behind the hcalds. The second arrangement is the mere ehective for narrow looms, as the " scissors-like " action of the warn threads appears to displace most of the dust to the sides. The exhaust draught has clTcc'.cd some iinrrovc'r.ent. but all the dust is not removed, especially tu.it nroduccd bv (b). It mav be impracticable to apply the draught to all dust-producing points behind the hcalds. particularly at long looms, but greater success would have been achieved with more powerful draught and larger air displacements, as is now being recognised. The methods described for dealing with the dust created bv (hi must be less successful at cloth looms of ordinary width. A few sue!: looms m one factory have rcr-ntlv been equipped with large " bonnet " hnrvA fitted t.-.insvcrsciv, close down over the machine, enveruig the slav. reed ami hc.dds The hoods are of heini'-'|i,'rieal section, with extensions over tiic sliintle foxes. An internal electric light filling, and hinge,) sections, facilitate working A powerful draught, suitably applied, should prevent c'ennc of dust, generated within. In another case, experiment is said to have shown that a transverse inclined hoed faring the operative, placed inst lvlow the warp near the Trent of the Iwm. ran be more .-iTeetive for reducing dust ronerntrution in the air breathed, than present arrangements, ami the new design is to lw substituted. 26 Application of efficient dust removal a.v .r.g?~cr.: = to weaving is cicariv difficult. Tliu expedient of installing indu. i.;al tune:..acs or small groups ef machines m suitable ventilated -mall room? or ''nine.vs. as suggested mirier " AVar;> 11tr " does not appear to have been ;r;c'i. but r:;ttrhI be considered if localised arrangements arc not suilivientiy r'rctue Long narrow sheds, ror a single line of looms, ventilated as suggest:!, nncht tc a possiole alternative. Cloth Pickinn. LanaiiiM, .'/ervuriao.--There operation.' involve running out the roils of `.li'tb and tend to produce a 'mall amount ot dust. If carcfuiiv ' done, so that verv little dust is created, other prccauticr.s mav be unnecessary. i , Non-Text:'.!:. 1 Fiberiicd asbestos is not used in some of the :. !i-tex:::e factories and exposure to asbestos dust mav he slight or ."-eu r.eg'.tgg'ie Dust is evolved in ' factories or departments whore such mntcrnii is prevrod for subsequent use. 1 or for sale, anti also m departments where f.ben.ted utatci nai or dry mixtures ' containing it are manipulated in preliminary manufacturing processes. Again. finishing processes, involving abrading or cutting at high speed, mav be a source . of d'-:t, but 'uch dust mav contain only a smnii nerc'iitage of asbestos. The application of exhaust draught, where suggested ::: the 1" >i 1 ov 1 ntr description ! of processes, is in most cases a straightforward prm'io--. comramble with many 1 others met with m non-textile lactones, eg . wooriwc:x;;;g and grinding, where machinery similar to tliat described is used :i Fiberszino or 0]>*nin->.--Fiberizing is '.inics; exclusively confined to works ! in groups (h) anti (r) Much of the work := dot.-; ::r. mr le-s supervision tb.au jj in textile factories and unsatisfactory ms.;;:: tier;.- i = more common. Primitive d teasers (" devils ") are used in several m.tttress-m.aking works, and chamber i; work is also an unsatisfactory feature (see p 22". In some asbestos-cement sheet factories, crushed material, from edge runners, falls into worm conveyors below, winch tran.-tcr it lut.i'.uticaiiy to disintegrators. In one large works, the process is being entirely er.'mseJ: the material from the edge runners, which are lattice-fed, v... be disci.arced upon a conveyor and raised by an elevator to large oveibead .'image Imp'ms. fitted with automatic bagging lattices. Localised exhaust drag grit will oe applied at feeding and delivery points, where dust might escape Chambers have been eliminated in some large works, with, beneficial results. The material, after being disintegrated cr opened. fa::-i:.atidied, and biown to a hopper fitted with bottom rotary deii'-my valves, the air reing re-c;rcuia;eil. , The material is bagged a: lattices. Dire : supply t: a r.iaitutacturins point is j. another improvement now being tried, r :c!i p: cut:mne eor.vevauce siiouid be i practicable in many cases. Localised ex. .a-t ..t :. ii::.; and discharge point: of these svstenis is necessarv. Vacuum -.ethocs :_m tilling sacks mav also be practicable. If chambers are retained, the uecesMt" for j,!ter::ig them might be avoided, bv providing ehambers of small front to ack d:me-.'tons fitto-i with low doors, at which sack Idling would be clone, local.-ed exhaust ventilation being applied over the doors. (b) Millboard, Paper. Sheets and Tiles. - The wet mixtures for millboard, peer, and n~iv-un:-cement products are prepared in a heater, as used in paper m...ls. Drv i.ber: tee asbestos is emptied into the heater trough, tile sack.- being sunken to -ome .'xtent. Evolution of dust occurs before the material Iviumes turned w;th t.m circulating water. Occasionallv a sack is emptied hoiorc the "-.ter is turned on several sacks arc required for a charge and the process r**(vtv.i a number of times dailv. Precautions are imt taken at present '"it the dust might be r.\oiiied by (ii) mechanical feeiimg under rncl"sed e'-ditiiia:. a: appear' to bt* none in siunc foreign works. (/.) applying exhaust dr.-.u-giit, (el feeding in small quantities and in such a way that the material is wetted at once. Finishing processes on ashcstos-cvnint sheets include sawing to size, corru gating. pressing and drilling, carried e.n in some fax-tone* with the material ' so moist as to prevent dust, and tins practice should be adopted generally. Otherwise much dust i- produced i:i sawing. owing t.- tne t.ipid cutting ?- eed, and localised exhaust. is neccs-mv though not. applied. Muni.iriv. turning, filing and smoothing 01 drv asbestos-cement pipes, at lathes, may requite to remove the dust piodmed. Synthetic coinpnsitn.n sheeting, sometimes made m a rubber department, is produced from dough tuiisisting of 1 tb"rized nst'estes and rubber, mixed th solvent in kneading machines-. Dust is produced in feeding the mixer with asbestos, done in an open manner In' hand, from sacks or sitips. the sacits teing shaken out, or from an open lattice feed. Subsequent pmcesses are dust-::ee Exhaust should be appiied at the feeding point. (c) Insulation Materials and Articles- Composition' --" Magnesia. the must lmroilnru insulating eonipcsi'.'.on. is produced on a i.irttc scale by the principal manufacturer. by enclosed me:nods with pneumatic conveyance of tiic mixture to automatic suit fillers. Wctruing and feeding the fibcn.-.cd asbestos gives rise to dust for which exhaust is necessary. Fibcri'd asbestos ur " magnesia " is a component of many insulating com positions which ir.av a.so contain ciav, kiesclg dir. fo-sii meal. liax, hentt: or jute waste and other :r...tennis. The proportion of asceste-s 1 n the final pi tenet varies widely. In nm.-.v small works the mater:.tis are mixed " dry." b.y hand, in an open manner, invoicing sack empuing ar-- fining. -ii'iveiiimc and -etziiicg. Enclosed rotarv mixers could apparent.;-' be use'i it such work with exhaust applied at : ceding points aim the natter'..il ut-tiui ued and ttczeu under enclosed conditions, If hand work is retained, exhaust should be attuned. Consolidated --Larue sheets resembling thick mats, built up of layers of fiberized asbestos, are consolidated with silicate of soda, sprayed on ir. manu facture. The sheets may be backed on one fate -.:h millboard, or supplied without a backing, being faced when fixed wtttr millboard or asbestos-cement sheets. The sheets are pr niuccd of the required s.:e ar.d shape at work reaches, or built up on the tan.o ot a liiachuie. capable flow re;:urocattng movement. and fed from a hopper above. In the former case, tire nberi/ed material is 'aaer. in handfuls from ski:- and spread out m the terms. the surplus being stmnec awav and failin': abeat at the sides of the wcr.t bench;;. and uii the r!-_.:s. a considerable qiiantitv being -cattcred. Dust, predticed it: man inn kiting t.'.e drv fibre, before trentmeiu with the silicate of soda. ;* largely avoided at the machine. Efficient localised exhaust sliouid be applied to the hand process with improves bench arrangements, to prevent scattering. Band sawing of piled sheets, causes evolution ct tut:;':: 'lust, owintr to the considerable depth of cut. Ixjcaiiscd exhaust alone. act yet applied, may prove insufficient. Sections mid Sioi: --Moulded insulation is made chtetlv in two fern; sec tions--senii-cvliinirirai and moulded hoiiow to .-.at varmu- pipe sates--and slabs, which are rectangular and solid. Those products are usualiv mnuided wet. either by hand or machine!". trom a pn-ic ur cream, prepare.', tri a mixing cimte ur tank. Feeding ot drv material involves e 'iiitl'"i of dn-'t .'mb a::; .: he avoided be one of the methods suggested tor feeding beateis in millboard making Sections are made at one factory by a dry pro,es. at machine mb:: reutly enclosed. Feed liopivi s. Idled i rum -kins, deia-er the n-t-esto- m mterna! !..ttiers which in turn supple a travelling band, at wh h ttie -e-. tnui is l ulled f" .'.am: Kevolving brushes which < Ivar the lattice an! spu-ad the material cvctt.y c:t tile baud give ri-u to much dti-1. and dust i- tumiined .tt the hoppers. ami tr. rolling and brushing awav -upei lltnms uiateria' Uxiiau-t dranglit. nut :..t;.crtc i.pplied. is to be urovuied at ibe expu-ed bru-a. ain: 11:machine is to c-c more eflcctivelv enelo-ed. An encm-ed 1 U-cd is u..-ei neves-ary. The sections and slabs are tiimmed to sire with circular nr baud saws Much du<t is (irodn. ed and exhaust draught is rommonly applied, hut is at some eases incllirieiil ( inular saws iij-ctl in some eases in pairs. 1'nr trimming ends in one oi>oratinii, can lx; lilted with exhaust lands almvc and below the benches. :>3 mij band saws can he enclosed below the tames am: t:iv<-s ted iwods fitted. the exhuen 11.111111 being applied .is for woodworking iirHiiiies. L.ucien: ai rangeincnts siiuulo !>c rendilv ]>inclicahlo for all sawing won; here .'/attrcy.'cs. -- Mattresses are manufactured by practically all firms wno produce insulation requisites, though onlv occasionalb. he some, Mattresses tor large contracts arc made in the contractors' picmiscs. tlicir outdoor stall taking necessary measurements and preparing rough pinn.s. A mattress has sometimes to be made on site. Mattress making involves, broadtv speaking, the sequence of processes associated with the niakimr of demesne mattresses. The work is almost entirely band work. Lengths of asbestos doth lor covers are cut out on a wide bench and sewn up. Iw treadle or power driven machines, to an extent depending on the method of liilimr. Larue mattresses may be sewn along one side only or ooth sides mav be seamed and lilliug done lmm iioth ends H,: oic idling, covers arc turned inside out. auppiics of Idling material, which usually, but may cot, contain fiberizcd a-bestos. are brought, in sacks or skips, from chambers, or taken from open bins, in the room, kept supplied from the chambers, or ircm sacks of material supplied bv outside linns. Filling is done by mam:, scoop or snovel. and Quantities mav lie weighed. The end Idling of long .loumo-scancd matt.esses, referred to above, necessitates the workmen mounting on the I each to empty the material from skips into tiie openings. Alter filling, the iv.af.re-s is icvellcd or beaten, to make tiie filling lie evcnlv within, the hand or a da: wooden beater being used. Finishing processes include anal sewing, sttiouing or buttoning, fixing on hooks, etc. Some dust is produced at the cutting out bene::, in opening out the roll of cloth, and at the 'owing machine, but far more in taking material from bins or sacks, in weighing, filling and levelling:. Beating c; the ciotii produces asbestos dust, the amount of which is largely increased if tiie lining contains asbestos. The work is largelv done without regard to the nece^nv for suppressing dust. All benches are entirely open. Localised exhaust draught is not applied. One firm have improved conditions considerably by the following pre- *v cautions :-- (c.) Keeping Hours and benches damp ami '.graving covers before filling. Hose connections and spray lilting' are provided. (b) Sub-division of department into sever.-.i independent workrooms (c) Exclusion during tiding of all workers nut so employed, the excluded workers proceeding to another scctirn. (a) Mechanical ventilation of each room ay era" ventilation. embodving plenum supple ("wanned when necessary) at me side and low level extraction at the opposite side, the air being charged between 10 and 20 times per hour. (e) Enforcement of use. by fillers, of re?-:rn;u.-s These precautions do not include application e: i-c:ii:.-',i exhaust ventiminu. without whirl) mattress filling and beating ain't involve ">i::o risk of inhalation of dust. For small mattresses, a wide doublc-ided cni'-picd bench with exhaust draught applied at gratings along the -mire hue night I e used, tiie tilling material being supplied within the canopy, buck a bench mav m-t : crimps lie practicable for the making of large mattresses bn; th- p-'sib-.h:;.- should be explored. Otherwise at least the precautions referred to above should be adopted. (d) Brake and Clutch Linings. Before being impregnated, tin: dry a-.bcsios 111. known as " grey," may be calcmleiod at squaring rolls and in all ciws 11e-nls arc eased cut t i separate them a little, -o ensuring thorough treatment by tin- Inpi.d. A little dust is produced in tlic-e upvinlnms but uisuliuient to render 'pcvial picvuulionnry measures imissirv. Ullicr piepnriitorv work'on " grey " arises in the making of speeial linings Length* of cloth are lightly liammorcd to ring 'hare, in templates, then eut with chisel or shears ami the radial edges sewn together at a winvstiteliiug machine, as used in book-lunding, J)n~t occurs in hammering .and stitching. A canopied Urneli lilted with localised exhaust air.iugcmeuts might be provided a ml the maeliine placed umlcr exhaust draught. . H { r ! 2'i L'ty irr.precmitrd materia; is shaped .-.mi finished :im:ntin- imwcr-driveu machines, e.-A ki.ivc'. cir...!ar ami e'nliouiio. cutt;m_* piio^c-. H' mamic >r,ucec:ug piessc-and tun.; saws Cult:;).' .--.mi sawing cx|><*o emi> i>; wire and leave rouu'ii ecues. :: ai;:;-.:::u and -i::-. .liiii.u'. iinc on urimiiv.-hccls ami li.-ushers. are neccssnrv to obtain cxai t ';zc ami i.uisii All tlic a pe ra 11- u s, except scravczing. procute w;. = tc. ami dust is created in s-unc. The dust is heavy and sticky and less i;kelv to t!v .i 1 >..1 st than drv asbestos dust. The amount is considerable at sa-.vir.a ami dm.- uiaN.incs and localise.! exhaust drnuuut. to remove it. has been anulicu--;u some cases `.viti: much success--ami is alwajs necessary. Inverted arc f.ttcd at hand saws. 'list below the tables, the dust being draw-, tbreaier, :nc suim. opeinutts in the tame guides. A poweriui uiaugiit is essential. ( Grinding and ii-i'hiri; wheels include. in addition to onhuarv smtrie-disc mach.i.cR. g.vn.dis.- ami vertical srtiuiie 'C-err.eiit.il gi-uider*. used lor llat linings. The r.cods by whitii the uTaueiit is applied to all these ivr-.-s are similar to those applied to the same machines when used tor metal grinding. -The position is similar as rcte.-.r : liaisr.ers. a hood being fated in line witii and at the back of the hand. A mule plate to prevent dust L-etng earned past die hood by the high linear speed 01 i:;e hand is a necessary addition. Sneciai iiitinas ar.d anti-friction bushes are mnunie-i mini disintegrated itsyr-rtniated -.waste. i'--w.e dust is created in the ;T!Ii::ir >: moulds and cihcient localised exhaust drana'iit mav be r.ercssarv The articles -ire shaped ami finished as jus: described. are turned and bored 1:1 hum.', witii production of waste and dust. but exhaust draught is not at present arpiiod though possibly (e) Packing and Jointings. Eagir.e racking is either In) " cicth " packing built up trora doth, usually rubber proote-d on hot:: sides, handlin': of winch does not cause dust, and lb) rope " racking made from yarn, at braidiuu ar.u plaiting machinery, as used in textile factor:-;, (a) Negligible amounts of oust may arise at the t soreadioc machine, from the unnrooiea cioth. and. in building up. from material erected on or.e side or.:-.- it) ' Cheeses " of yarn are hrst rewound on bobbins tor tne braiu.u. and plaiting machines. Simple winding nxciiani-nis are used. Some little riiiA is prcuuecd, sneciai preventive measures w--.ll usually not be necessary. Slat packing, known .is " grummet." is made, on a small scaie. from asbestos varn. tiireaded on a needle and wound in and out by ham.:, as bails of wool are wound. Thus apparent;-.' insignificant process causes su:::r:ent dust to cover in a snort time the aair and clothing ef the workers ami siiouh: be dime at a canopied bench Drcvided with localised exhaust arrangcaients. (1) Asbestos-covered Electric Conductcrs. EUctrnd*!--Electrodes aie either wrapped wui: \a;a. i!;e mu.nl method i cr passed through paste containing asbestos Imre, yarn being ".vr.apped upon tins i coating. Tiie tornier method is usually achieve! bv a sinni: high speed stranding machine fitted witii a liter carrying ibe snoois or bobbins of varn. the wire travelling axtailv through the ilier. Treatment witii . nii-niiiiatir.g Inuid, strragiitenniu ami cutting to length follow, ail done at the 'tramiuiu machine. Altcrnali'ciy. smgie electrodes mav be wrapped In- a simple winding mevimai.-m. haad-oper.atec or r.nwcr-drivcn. i'astc-covcred electrodes :i:.' also made singly at small extruding'machines, a liicr for feeding the yarn being fitted behind the extruder. After drving. .1 short length of the covering at one .-ml is ground awav, leaving the bare metal iievcssarv for mailing electrical -intact m the liouicr. whc.a in use. Small abrasive wheels, almost entirely cm io--cd. arc used. Small amounts of dust are projected from liters, though insulUcieiit prob able In reepme tin- .idnption m special preeautious. Mo. Ii dust is produced in grinding ends ami elhcietil cxliaiist ventilation is essential: present apparatus, where prc.vided. is rapahlo of improvement. Tlie process would be unnecessary if liared ends '-.ere lel t in ai.tiuiiai lure, and experiments direeled to this desirable end are being made aud give promise ol success. 5- IJU Prc'p.u aloi y piucvs.-.e; m gjste making ::__ icic . y g:.:._.:ig :. erired Cibcslus Ly si:i.ill iciln.il < 11 cl iiuliiu nine- :c-: .. 1 ...-.- lun. coove .Uiu uiscli.ui.vii i rum l..e pel lplierv ml. . i" \ 1 ... I:..:. 01 theg.'uiind 111.1 lei i.i 11 nl n arm h. imoliiii.' .... : ... a:..; pal:; Last is i-iodmed, liie amount being n asoa . .ie : g'. precaution IS taken. liie processes mi-gilt be ..a-xi'..; g; '..1 -- .' c.r:.e~ eacloscii coiiJitiuiis. rlhcicnt exhaust uni up..:, uc:i,g -t pciu ts a i.ere dry material is exposed, e.s-. m : ceding. Itcwi ndmq of yarn is sometimes necessarv ami xt dc used, tl:e practice reterred :.i on [wito J4 U. g i"ib amount 01 di.sl 1.' nioJuced. the* |u.u:ice ;h- ..u 1 e a. ui-.- a: :.::sge::.o:.t; t:;av -i. a tons.eicradie u 1.. Cable and IVimi'j.--AsLcstos-eoicred ca. .e ..mi stitutc r. suull percentage 01 the output nt the cabie lactones i ::e :: . :... id and : ir.ited on the conductoi s u maeiunes. nut reserved :`.r " .-t-ss ' ::eiaets. similar to those previously hc-enbe-d. i'.cwimhng of " :::ees..-s '- i trem asnest as textile lactones. is none at universal wuxii: g mariur.:; i ,.r -xipuu; c: uu-t evolved 15 small, anei special precautionary me-sures a:-: apunrei.t.v not rccuired. Field-coil \Vrnypi:n>.-- Field coils for e.'-rttncai " '. r'.re wetrri with asbestos tape by hand at ordinary work bertae;. T:e ::r'c-:* dees act give rise to anureeiable quantities of dust. (g) Miscellarirtus. Moulded (lnr,,(:. -- dome electrical iusu.o.:intr n::.. g; txouide.i from varnish-imprcttna.teu tibenzed asbestos, pier .red a:::: drying m a mixer and ground in an cage runner. Alternative:;.'. :. yreg-..::.. scrap, ground in a rummer, uiav be usee!. The preparatory .-tc-.-.-rSe: .a ::- ::rac::.:..ly cry material are intermittent, and involve sac.-: empty:: 0. . -..mg. weighing, tailing and emptying shallow trays. They are car;-:-.-, mi ::: tn open manner without special precautions except that as rrgarus gr.-.-i:::g. : rtgir.c curtains may be used at the edge runner, aud the strap rut:, t ir :s?d. Fas; is evolved in the processes mentioned and loca..=ed ex:__ A vrr.::..'.:ion sr.miu be applied to efietit its removal, with, in addition, ei'iettn-' e:i . 0; some hand work, e g . emptying of trays into m.ichin:; calcic : -inxe aside a rabirte: provided with internal arrangement; for s-:-raring :: e tiny. \:.l ar. external handle tor turning them ever. Localised em.aust r.tv ae n-.-;rSsary tor dual trimming if done at abrading wheels. Moulded articles made in other trades .ray co::_.\ if:: a ;~:a:i proportion of asbestos, although a large quuutitvmav .e Jced. in e..`.se the asbestos is sieved after rirvr.u:, both operations being lone ;:ud d machines, and, in addition, drv mixing, done in rotary mr;..;ues. . pa-ixing. ers open rolls, as in rubber works, are also ic-quirec Freer--... gmrr.. -t. wit:; seme risk of exposure to dust include emptying :: i-ac!;; .. : f.tiing *: trr.vs for diving, feeding at liie sieve elevator ho a s :..a rras Localised exhaust is applied at (/) the elcvarv ! m: :r ' . t _ -image ex amber above an intermediate bagging point, if) the m.:v.f f.a ' tr.e :r:.; Mere etTicient arrangement; appear to be desirable tor :f' ' ` ' t .. teecltrg ci the elevator aught be done under enclosed condit: as it .1 . ix.: .-= -.ntioue i a cove were provided into winch the trace could c in-ert . ..-0: exr.v.tst is neccssarv at storage bins. Final trimming c: rough cages is d x.e under edicient exhaust draught. Other proers-vs of cnmpnrativelv nunc tmpartv f'. e g ashes:.-; auttv mixing, in which there is handing ami tcecx.g 0: dry --a:-'-: . ;u pteparatory rirocesses. will rail lor precautions as prcvi,-..;:v nc<rr:t..'>i f-.-r similar work. 4.--Sarx's In a few cases sack's of -.lilrlntli or nti.'r close:-. tleriai .ire used inside the factories Sinli -ai l.s are much ; be ;-r--- t o -e made of the ordinarv material, ulucb is " leaky and gres rise L-: -lust tn . ..inning. 5.--CutAMsr. ov Works. Ma iuneuy s.- n Sack; Some factories are kept in a more rlr-aiv ~t.i!< than 'e...ers, lint liigher standards ami impimx-il methods are di*sira. :e grneredy W.v.siy eleauing bv dry metboils is general in textile factories, l--.it is more rlkvlnciy dour in some .11 cases than in others. Cn.Minl cleaning nitty also l*c Join- 'innii: tne week. The dllsl which gather' in ;t week render.' cleaning a verv du-lv operation. 'toning workers uiav be seen on curding inaclnnes bru'inng oust into the an Irom tin* covers, etc.. tn considerable amount. near other workers. Some tirms have instituted more in-nne.nt regular cleanings ami more sattslaclory lucthods by damping belore >w roping. . Vacuum cleaning methods have not been adopted and such methods seem to be regarded as imprurtu aide, hut tins can hauilv he accepted. Portable vacuum sets are cousinntlv used until great nev.mtnge in other rlnssr'-of work*, e g., eleetric cable lactones. In* adult eleiHiers who keep the machines, plant, service pipes, etc., thornr.ghlv clean. - If vacuum methods are not adopted, well ruga meed dailv ilearung, hv adults, using damp method; for thior cleaning, should bo the rule in textile tactorics. A water suppiv with suitable hose and spray connections should lie provided. Dbbris pmdiued in asiiesins-ccment, sheet works tinder moist conditions may become dry atui cause general dusty conditions. Cleaning should be so frequently done as to prevent this. . The cleaning under machines such as looms and cards entails collecting"" waste of considerable vaine none at present hv hand Vacuum collection should be possible : in principle, it is .a 1 read v-used for removing side waste at finishing cards. The sound principle of mllcc'ting'c'ar.i waste, thtough lloor openings, has been aborted ;n one new raetorv. and might be followed in others, with automatic collecting arrangements. ... - - -- - ""Sack cleaning is done in a few large works m enclc-ed machines, involving some risk of exposure tn dust in filling r.r.d emptying, notwithstanding the provision of localised exhaust ventilation. A type of " exhausted " machine which dees not involve such work is to be preterred. . ___ _ - - d."-SnMMARV AND RECOMMENDATIONS " - - . - Asbestos factories nod workshops'eover a great varictv of processes. The premises differ wnk-iv in structural features r.r.d are congested m ntativ cases with machinery or material. Processes are large:-.' carried on tn ctose association. Dust is produced at nianv kinds of maciiires. in hand process work, and in simple incidental operations. partn uharlv in emrtving settling chambers, aodiu all handling of '" lihenzcd "asbestos. .. . .- In textile factories, pure asbestos dust is : T.'.intumsly produced, in'differing amounts, at all the principal machines. Car-: dripaai;. a verv drstv operation, is usuallv effected In- hard strickles. Han i mixing of .iliicreot grades and varieties, incidental tn opening pm rwi's. is also ii:;.-!v _* " In nun-textile i.ntnnes. pure asbestos du>: : produc'd at ..ncuing laaciutK's. in 'feeding m;u iiiues. iu making insitluti ng mattresses; <a. riustv baud process!, and in incidental hand work. Dust, though rareiv pure asbestos. ' is produced m finishing operations, e.g., sawing, ^jrintliny' nmi other abrading nf asbescos" products. . . The appropriate methods for suppression of dust niav niilv be fullv deter-' mined when tin- Vominl elicits ol com pa rat :vcl v low ii'ri ,"U: alums of asbestos dust are dulv .1 ppri-. iatcd Verv dustv processes will no; fad ... Iv recognised.' but iu ppvi......s 'in ii as spuming and v.e'vmg. in which fn other textile trades ' special method' dust nntrnl are not required.. due pi o--.ni: urns arc also neces sary. The :i'i'0'tns nuuiul.nturcrs are Icanv con t muted with the neeessitv of attaining rnmiit ioiw in tia-ir mdiietrr .-ho n will ni;mr .... rh Ir" dust in liic atmosphere than can snlciv he tolerated in aiuuv comparable trades not usings asbestos. - - -The principal molhods for the toutml ro'.dusa arc:-- - (e) application oi exhaust draiig: ; at dust-t'roilnei n-g points: (h) siih'iilut ion of mcliwrrl meeiienn ul methods for hand convevanee. and for till-tv hand work geucrnliv: - . . (r) eflci t ive etu losute ol dust prnhueing ninrhines and plant: . (d) substitution of wet mctliods for dry. .g . C-'.:a n\ ihr-r !n it' p.oituaiiar -pbere >'! ulilitv. a::u ::u.- urtii ula.r indica tions ter tuc;r ;ii--:>L;cn aru put lurwaid inter tilia m the rccoiuendaiions below. RECOMMENDATIONS. (1) Application cf Efficient Localised Exhaust Ventilation at dust-producing points. T:;:s measure. ot '.be gicatcsl impm i.aitce where tuanuf.v-tur'.ng and incidental pro-::=;:= 'A-.i'ira v;vi.pe of dust aol vuuroiled by enclosure or other measures, is necessary for -- I'll U-l; :-]'roe, mnchim"t. eg -- uj Crushing. diMnicgrntiug, teasing and otiier opening machines: sieving machines; fibre grinding machines, dry mixing machines: roii. fed with dry mixings. (ii) Carding machines (to suppress oust from cylinder and doners, caused by stripping and grinding. :u addition to that pro duced by carding;: ermi side waste exliaa-t inn.dunes: looms tor dry weaving; <trip;iicg u..b grinding machines; other 'extiie machines, if the dust evolved renders this preventive measure necessary, (iii'i Sawing, grinding, trimming, polishing and otiier abrading machines, used on drv asbestos products. ib) Pceding and delivery lattices, or otiier conveyors, at machines or other piau:; feed hoppers at cievators; bagging lattices; feeding of dry material a; wet mixing machines. ic) Chnrabers. containers. " cyclone " hoppers, or other enclosed spnee into whicii f.berioed asbestos or mixtures containing it are delivered, or pass. (a) TTork benches, e.g. for mattress making, waste sorting. (c) Various hand operations, e.g., sack emptying and filling, weigh ing. mixing This is the principal measure hitherto adopted, and is probably that most generailv applicable. It has been apnlied to some only of the above machines, and appliances, but not to baud woiit. The methods ef appro mg the exhaust dr.augr.t. and otiier associated factors, are becoming more etiective. but there are few fuilv satisfactory piants. special liilficultics remain to be overcome in seme cases, c g . looms, mixing, mattress making. If not surmounted, an alternative, vi,--. general ventilation 01 a high standard applied so as to draw the cust-iadeu .ur a w.iv from the worker, should be provided Substitution ol enclosed mechanical methods for hand conveyance, and for dusty hand work generally. This measure-- (oi avoids depositing material in chambers, intermediate filling and em.otving of sacks or slaps, hand feeding of machines, and other incidental hand work: (?) permits of final filling and weighing, under the least dusty con I ditions. of materials for dispatch; I I (c) renders exhaust draught more eilecavc. or. in some cases, unnecessary. It is alrr.nbv emplnvcri to some extent, and its further application, wherever gossibic. is grcallv to bp desired. (3) Effective enclosure ol dust-producing machines and plant. (a) To pee' cut lmh|v of dust nut controlled by exhaust draught, or (b) to lender Us application mnrv cllicicilt. 1 * ' a !' i 1_ I , '` . I i j i i j | i j ) j* j jj I I 3.1 (4) Substitution, of wet methods for dry. To reduce the dust given uli in certain processes and work, c , (a) a consider,-iblc amount oi' weaving; (4) mattress making. iw wetting ih<` covers before filling, and by frequent wetting of Honrs and benches; (c) final sawing, and other machine processes, in asbestos-i c::.ent sncct and Idle factories, belore the pieparcd material has Lad time to dry; (rf) works' cleaning, hv damping doors ur.rl benches. beJcie brusatog or sweeping. This measure might be auupted to a greater extent than at : resent. (5) Elimination of certain dust-prcducing appliances. Certain appliances .arc used in a few works, sometimes wit;; a measure or precaution, but which emit much dust, uiiiicuit cr impossible to crewel by eificieut enclosure or exhaust draught. They siiould not be retained unless effectively modified. (a) (-vnoced dolTcr brush at carding machines: (4) card side waste exhaust machines, delivering und'W pre--urc; (c) certain willeys and leasers, particularly old machines (6) Abandonment of Settling Chambers in Manufacturing Processes, to the utmost extent. (7) Effectual separation of processes to prevent unnecessary exposure to dust. New factories should be laid out so as tc avoid exposing -.ranters to risk from processes upon which they arc not engaged. Iu particular, there should be effectual separation of-- " (a) opening, carding and weaving, from each other, and from any other process: (4) spinning, doubling, plaiting and similar proce;-.s. from work not causing dust; " (e) mattress making, from all oilier work; (rf) chambers, containing f.berized ad osics in built, and dust settling chambers and apparatus, from anv workroom. The separation of mattress making should he adopted in existing works, and other separation referred to, as far as practicable. " (8) Wide spacing of dust-prcducing machines in new factories and, as far as practicable,' in existing works. This measure would bring aUnit permanent reduction of d;:-: '-oncentration in the air of the workroom as a whole, and prrv.de improved cleaning facilities (9) Use of sacks of close texture material for internal work, (10) Efficient cleaning system with wide use of vacuum methods. (So- also i.4)) (11) Storage of asbestos and other goods to be outside workrooms. (12) Exclusion oi young persons from specially dusty work. A'ote.--Particular preventive measures of a medical nature arc referred to iu Part I. where also the limited value of respirators as a safeguard iu this industry is briefly discussed. 54 Noil: on Exhaust V:.\ti i atiun AauLai.: U'oi:i;.i. Some cxiuuM. ;>!.irjts are rarofullv designed and .-.a.MMiaoiv elliciejit. but some ere iiI- ic^itr1 >>'I and inclln.-icnt: others. ..gain. ........... cih-r: iemnv.il of dust to a sullicicut eMeut. I be draught m:.v not _ applied a- ch'-cly as possible to tlie liusi-pix im.ing p"int>. or mav be >> wee.; I lie of a visible dust cloud at a point where exhaust is applied is r. Avar imiaation of inadequacy. Extensive .iltcratimis of existing plants la-.v produce -.rnm< loss of efficiency. Exhaust provi-ien lor new maeliincrv ami p:'_es-e= shot::* 1. therefore, generally speak)!):', be made nulependcntlv. While .mvantages ic-nlt from dealing wuh many dust-producing [loints. hv a single exhaust plant, a Lumb-r "f self-contained piant?. witii imlepetnlent Ians ami settling ugparatus. ;? 'lieu mure ellcctive. Exhaust ventilation applied on a iartre s-;.:!e entail- uMtiuunus removal of a considerable volume ot air troin the room. The supra of ties!) air must be ample or the ctlirirncv of the exhaust vciiUiu'.rjii mav r,_"iu- cl. In winter, the workers are liaolc to bring about tins result bv clo-.: u windows and doors. Plenum ventilation capable of supplying the volume extracted, the incoming air being wanned, may therefore lie desirab.e. where extensive exhaust plants are installed. Ellioer.cv of an exhaust ventilation pin:.: mav be great!'-- reduced by in efficient du't-settlinu methods. Each tan sheuid discharge into an independent settler. Settlers adopted in asbestos work? include c? iom-s. hi rite chambers connected with cyclones, large chamber; encic*eri with - ..king "r other filterin'; material, and bag filters. Cyclones and chambers are .sualiv well separated from workrooms Dae filters are now being ogminonlv a : t tru. for small instal lations. Tlie-e Idlers and " balloons " are s.rnetines ; I ir-sidc workrooms, a bad practice. They are best placed in fceeiy venti.ated rooms, etfectively separated fiom workrooms. Filtering fabrics for settling du>` gradually heco:: e clogged: and as this effect increase? the exhaust plant becomes me:: ami nor: ineih. lent, the volume of air moved bv the fan being reduced. ."fu:h settlers must therefore be kept ciean. The usual practice is to beat the filtering mate-: u Arrangements fur shaking bag: from outside, or automatic shr..-::ug .ip:v :.'.:us arc not provided Asbestos du = t dm-s not appear to be so dither..: to 'iota : nun suitable filtering material a? ome dusts. but much dust is prouu-ed in K'.vuig Efficient shaking arrangements avoulmg this exposure, shot:. : be :'i ; ,d i; this method ot settling is retained Sump firms strongly su: port the view that it should he given up because of the diificultv.of maintain::.; tiie exhaust riant at the highest emnrnev. The matter merits careful cr suieraticr. I:: particular, the 'fTicieecv of the exhaust plant should be key: under c.T.stau: observation by a responsible person. Cvclot'.cs should be of adequate d i men?: . The ':: i r> i;: ->-;on of chamber and cvclone A used extensively. the fan disr: .aging :r.: nr into tfie chamber, to which the c.-cbme inlet is connected. Tlie exiciency o; tins arrangement should remain practically constant. E. R. A MEP.EVAETHER. CHA5. W. PRICE. 14th March. 10:5(1. iO*-4i *1 V I-TVT'H !** r 'i n 1 nr e