Document dYB6mjbvZkXVwk32Bmj2M2020

FILE NAME: Maryland Casualty Company (MCC) DATE: 1918 June DOC#: MCC005 DOCUMENT DESCRIPTION: US Dept of Labor Statistics - Mortality from Respiratory Diseases in Dusty Trades  I & C -? t A. U. S. DEPARTMENT OP LABOR U.S.BUREAU OF LABOR STATISTICS ROTAL MEEKER, CaamlM>av BULLETIN OF THE UNITED STATES I /WHOLE BUREAU OF LABOR STATISTICS! ' * * \ NUMBER J l IN D U S T R IA L A C C ID E N T S AND H Y C IE N E S E R IE S . N O . IT MORTALITY FROM RESPIRATORY D ISE A SE S IN DUSTY TRADES (INORGANIC DUSTS) BY FREDERICK U HOFFMAN TUNE, III* WAS HI NGTON GOVERNMENT PRINTING OPTICS IRIS * * r-> : * k *V> *mL. . _ & 3*>: , r' .k. .-.. 4% rfT * *w r* *9 **>. ** _ -4 t -- 172 MORTALITY FROM RESHRATORY DISEASES IN DUSTY TRADES. T \r.ir. 0__ PROPORTIOMATE MORTAMTY PROM PULMONARY T U n m c U L O S lS SPECIFIED t.MPUSTRtF.S OR OCCUPATIONS W |TR EXPOSURE TO OTHERA!. DI 1NPUSTRLAL EXPERIENCE OF PRUPENTtAL CO., lMf TO !U, DY AOS PERlOP- 11 M 2 T**n. M 3 r u n - lito u jm . M M run Occup&Uon paup. rwlhs t>*Uu D ^lbi fmm from from pMlmnrurr (Htlmootry pnlm m urn tut ***} tul*reu w i * t ^ !WM fromaU lout. from 11 lot. from Ml l o u frwnM l cause*. aunt cm n. Tw,,, I rom tohpw u* Hum- r n twr. onL Sum* P,r be*. CTOt Mao-1 r . te r. jtMC Mar' r Cr. ft Atl*U* wftfkofi, Ufrttnrklt.o.L.I.U.....4.a..d...i* m Cor i t t t k m . . . . . . . . nOutaMi hcivotviW nn.......... ...... ft ta u t? or k ft.olh # r. Licmynr,tttmn .a..t.a l , ad l.fthom pnan - U.v.M....a.n..O..l.i.o.n..*.w..o.r.k..* llokU n................. r i i a i u c i ....... JJ'Mn pjrsruhmosn k e r ...* ..... Potterm, T out. 4A It 31 f M 1* V. 3 112 3U 1 9< <21 L it M V >5 137 m si 2 j ^ m. :1 1 1 41 l s i t i . t i Ml 1% 30 3 U.-M f 7 i 1 i ra ' i 10<M A : P* Mlo yon. 45Tanaadotrr. AcaUBkoorro. 1 AsbriLM w o r k t n . . . ___ C ue*. HU. aod u m C>ero*imu .*...k...r..n. .............................. C la st O io w m ............... Gla** m u m , . . . . . . . . . . C lsr*or kers. nlb"T. . . JLIcmy*f,vtrr or a..t.o..l.......n..d l.U h o c ra p h rr :............. Mfsvrti>.U.....a...to..r.>*. workMoidm......... . P a tn i la c to r t ......... pP*iwt*irmh nn.j.?.n................. returns........... TiMal... . ,i 3 j 3* z liJi8 n3 t1f1t..74 I7\Si 6 4.7 j } IIZvl?v as 5343 %2 IV.34 M11 ;Sii 75i..931|........1 73 1~ M SO A IW 16 U.5 3 j 5.4........ MTj 6 112 32 i 4S........ r<i v 773 4* S 33 4 l i : 19 ? tO..4 i XV- *. 'I 5020<6 1417' 13.:' 3i&12 3Z'\! 3..81................ : :.osz oi ** 3.:>m J%54 n 1\ ^ T14. !....4..2........ 1211 T0*M 117i1 3391.1511,. 31ht HU 142..Oii................ .w L' smi r. ir1 <j lA?j !,CS 109| S.ij ......1..... n,c;7| j.i.vj MORTALITY FROM NONTURERCULOUS RESPIRATORY DISEASF.' On account of the importance of nontnherculous respiratory dii or-os,' Table 70 is included, showing the proportionate mortal' from asthma, bronchitis, pneumonia, and other respiratory discs*' 'O n ilie nooOMwrf'ul'm n*tlrat*ry dls*, *# ** r>Kr*<* of 15 tW aorhl. LotC and lit Kr* tlrt< r. I^L M. 1. I'bMod. ipbU ml N*w T o rt, 1 0 1 ', * SrM.-m nf Mlieta;* rUllctl Uy b if Clifford Jib u ti 4 ad Itu m p ar ? D * t j ttullcilU 1009, * * S % OCCUPATIONS WITH ESTOSUHE TO MINERAL DUST. 173 owm j unnnc workers in occupations with exposure to mineral dust, without ^ (eiTnce to divisional periods of life; - 8 -PROPORTIONATE MORTALITY TR0M N O N T U nER nrU JC S RESPIRATOR v ?i*i *fases in specified industries on nrrirpATioNS with exposure to miv IUAL MUST INDUSTRIAL EXPERIENCE OF PRUDENTIAL CO., 97 TO 1914. DtUtucaasad hy a o D la b tm la u im p ira u ir <U>*. i^itinyonsroap. Ailbma. n ronehills. rmamoBiA. OUmt. TuUI. Nam* rr Nura. r* r Niim* Pr Niun- rvr N'nm* J T>r U r. cent. U r. n n t . U r. C9QU U r. cent. U r. | C*Ui. ...... * ..e..r....u.l..,..a.n.d...t.e.r..n. * | n* . ,..l4otfrs............... . ............... o in e r.... V, tv *miuiiad in '* Il t>i'^.n.Txi4iiuihsfifueQ..t.v..o.r..f.r Ua*%........ \ *tt:netnnn. i 'Hvtngen,. *t iM u m ..,. | TotU. 8 i.i 3 .5 1 .5 4 .4 2 .9 28 t. 4 15 .8 1 .8 t .1 9 .7 28 3.1 105 1 ' 9 3 15.3 S 0.9 l .3 8 i.i 1 .3 6 .7 6* 12.9 40 11.3 33 5.9 21 9.5 71 7. 3 1.1 3 .9 IS AS 33 10.8 SI I S 191 9.5 1 1.3 4 14.1 u 8.9 8 l.l flt 8.8 23 1.7 138 9.8 14 1.7 1 19 5.7 173 1 " | 1.193 t a s 2 15.3 10 1.9 7 2.0 8 1.5 .9 ii L4 $9 ir,.9 48 1.1.4 49 9.0 13 11.4 94 10.5 s 13 3 .9 a 11.3 41 1X7 49 2.4 65 2.0 9 1.3 9 .7 19 2.4 327 13.9 004 18.3 12 ft. 7 M U.2 176 1X8 104 11 9 199 1.7 !,t>75 14.8 \ 11.Iocs not seem necessary, as observed in the discussion of occupa- . li'>u> with exposure to metallic dust, to enlarge upon the facts dis- <>*'1 by tlie preceding comparative statistics, wliich emphasize with . uflicient degree of scientific conelusiveness the obviously health- . injurious consequences of considerable and continuous exposure to f iulialation of mineral dust. It is clearly recognized that the sta- ' ''ticiil data utilized for the present purpose are of rather limited r` :,i*ni`sic value, but they are in the main quite fully confirmed by the i m.Tfi extended consideration of occupations in detail wheru the ox- iHMire to mineral dust is sufficient to warrant their inclusion within . the plan and scope of the present discussion. w i ' i \ A ENGLISH OCCUPATIONAL .MORTALITY DATA. * Tn conclusion, however, it has seemed advisable to add to the pres- , fM observations a tablo obtained from English official sources which j, the combined mortality of glassworkers, potters, paper * . n ,'-('rs, plasterers, and lithographers, and which may safely be *m.Mdcrcd sufficiently representative of the entire group of occupa- . ." ,,s exposure to mineral dust, in the absence of more extensive * . ln "rmatiou which unfortunately is not available. I " ^ >1 . '- . * 174 MORTALITY FROM RLSI'ilUTOHY DISEASES IN DUSTY TRADES. t 'Vk.l T am.* I t . --MORTALITY FROM ALT, CAUSES. FROM PULMONARY TV R E R crLO ST S. Av FROM OTHER RESPIRATORY DISEASES IN OCCUPATIONS EXPOSED TO MINE?; DUST. COMPARED WITH T 11\T OF ALL OCCUPIED MALES, IN ENGLAND y WALES, 00 TO KOI, BY ARE OROUrS. m o u trr r u t I t, S apnl*aat 1 IS . St*tT.rth Annail Rrnort o( lh* R tis tru -G u n i < Birth. D,e ud tumni u>EnclAodUM*alM t 4 4 T> D eath r a u per 1,000 duo to alt eauMe amooi-- Death rat* ear 1,000 d o a la ptiimooarr tobacco Infif >nX1TI| J D e al* ra te p a r i.orn 4 to (bar <4****-< tho respirator^ s ? -, im oftt 1 A o itd a O . r>,. -M^Sm All o r - Occupation ifioen^U) O o o w U a u AD ocro- OoespattoF- r n w j ta am ptJ tsoiM uuoerat dual. pjad maJea. miD***i lia il. g i M s u i . ttta a ra id v Lfiii iias?o^Sl r^ f$ : \ i& .3 A5 ^ . - .-.v jlS i Y ^ X - .. * ar- T *~ V4 HC>w i j-5* -It3-' A-. 7T.,.. |f e ;sS5S. * C " ''*! o :* VSf*L~- a IS la In * . -- ~ ........ 144 125 0. M ass 0-24 l 4. 1 4.03 l.M 144 .4 $ r . u>31 i a n . . . . . . . . . . . 6.01 3.34 ICO 101 .n tm \ X to XT* 1 LM 1 43 to .44 y e a r .....--. . . . - t7. n 3.74 104 4.91 132 t 31.01 40. 23 1 16 IM 4.S4 11 U r m n M d o n e ....... a 7 X OO LU 1.U k. n it GENERAL CONCLUSIONS. Table 71 brings out clearly the fact that the mortality pulmonary tuberculosis among men in occupations with expos.: to mineral dust is decidedly excessive at ages 35 to G4, but-:, the mortality at the other ages is not appreciably lower than i occupied males generally. Death rates are, however, not os ui.1:. and conclusive for purposes of industrial hygiene as the proporti't nte mortality figure which precisely emphasizes the quantitative i/t portnnee of a given disease or cause of death. Tho proportion mortality from pulmonary tuberculosis and nontuberculous resp:-' tory disenses is excessive at all ages among men with exposure mineral dust, although the relative death rate per thousand expose to risk is not, at least according to English experience, decided excessive at certain periods of life.. The data are not of sufticir importance to invalidate the general conclusion, and in the main t? death rates sustain the proportionate mortality figure, although lh is not invariably the case. The death rate from nontnbenrulcrespiratory diseases among men employed in occupations with ? posure to mineral dust, according to the English experience, it: the older ages so decidedly excessive that obviously much tr.c extended scientific consideration should be given to tliis group disuses than has heretofore been given i t At nges 55 to 04, i illustration, in the English experience there is an actual excess the mortality from all onuses among men exposed to mineral-dust 0.22 per 1,000, equivalent to 20.7 per cent, but in the mortality fic pulmonary tuberculosis there is an excess of 1.73 per 1.000, equi' lent to b2.1 irt cunt, agninst an excels of C.Cj pvr 1,C00 In the n:c O C C U T A IIO K S WITH. EXPOSUBS TO MIXE&AL DUST. 175 itility fro" nontuberculous respiratory diseases, equivalent to PO.G j*r cent. The results of this analysis, therefore, reemphasize the 1fciriiiific coodusiveness of the extended discussion on " Industrial j nrumoconiosis with special reference to dust phthisis," by Edgar L. ifodis, in the Milroy Lectures of 1015, and the corresponding obser- lotion s on pneumoconiosis by Sir Tbomas Oliver in Alibtut & ; on's System of Medicine, Volume V, Diseases of the Hespim. ' toiv System . * O f interest in this connection are the observations by Dr. J. S. .. ]til.lane contained in a contribution to the Proceedings o the Insti- nui'ui of Mining Engineers, abstracted in a letter from London to t the Journal of the American Medical Association, August 19, 1910. * In die paper referred to Dr. Haldane pointed out " that while up to *die age of 50 the death rato from lung diseaso is much lower among . ..'tiers than in the rest of the population, above 50 thu opposite holds, ami there is a marked excess of deaths from bronchitis.'' In con1 uumitioa, however, he stated that " the deaths from this disease have ' yn-mly diminished since 1800, for which improved ventilation seems J u. Ik- the cause. Fifty years ago miners often worked in air coni mining so much black damp that lamps and candles burned dimly. ?In Mich air there is usually 2 or 3 per cent of carbon dioxide, which *itinnnously increases the breathing during muscular exertion. The *l'n-.ithing is exactly regulated so as to keep an average of about u.6 |*w rent carbon dioxide in the alveolar air; and with 3 per cent of this gas in the air, a man breathes twice as much air, so as to keep *tin- alveolar percentage right A man doing modemte muscular \">rk in pure air breathes about fivo or six times as mnch air as dur- ,tw g rest In air containing 3 per cent of carbon dioxide he would 1- breathing ten or twelve times as much air as during rest, and his . 'ybn-.ithing would be taxed to the utmost. lie would thus be much . ii*''ik* liable to contract emphysema. The better ventilation of coal *J limits is largely a consequence of the greater amount of fire damp and ygri-at heat encountered as mines hare become deeper." : I>r. Haldane is inclined to think " that both the fire damp and the 'h'-nt hare indirectly caused great improvement to tho health of *'4- ln.rs. Where there is plenty of fire damp there is usually also , of fresh and dry air, ami no harmful excess of carbon dioxide. ' proportion of deaths from bronchitis among old miners was : |"'clirr in Staffordshire in 1S90-18K and 1900-1902 than in any of ,d-*-'*h*r coal fields; and Staffordshire mines are exceptionally sub- !]"* to black damp. The excess in bronchitis among old coal miners ! VTM attributed to the brvalhing of dust," and Dr. Haldane was t t'oesimisiy inclined to agree with this theory, lhit it is diilivult to hL ^ is tho cause, there bos been so great i diminution m "J 1 * 1 T " V - * SK . MORTALITY FROM RESPIRATORY DISEASES I DUSTY TRAJOtS tlio bronchitis mortality in recent years. Coal mines have, on whole, becomo drier and more dusty with increasing depth ami bet ventilation; and, if dust were the cause, one would hava expected brotichitis to increase, whereas it has greatly diminished. Ccrtm r.n excess in mortality from bronchitis is associated with the broa ing of harmful dust. But this excess is accompanied by a far gre.n excess in mortality from phthisis, and begins comparatively earlv life, unlike the bronchitis mortality in colliers. Experiments animals carried out by .T. II. Beattie show that both cool dust and slmle dust usually associated with it on mine roads are relativ harmless." It is therefore quite clear that much remains to bo Asc tained concerning the true nature and extent of dust phthisis r that in the solution of this important industrial problem a c'-~ erable advance is necessary in the practice of medicine, which much larger degree should bo made to rest upon knowledge, coming disease causation ascertained by means of autopsies in :r.>: trial districts subject to an excessive mortality from pulnmr tubcrculosi3 and nontuberculous respiratory diseases. ASBESTOS. The number of men employed in trades and industries invoh exposure to asbestos dust in the United States is unknown. As from the mining of asbestos, in which exposure is rather limn there are numerous processes involving tho conversion or return facture of the materials winch are distinctly more serious iiTth' effects on health and longevity. Asbestos weaving and spinning described by Nctolitzki on the basis of observations in Bhem where the conditions were found to be decidedly unfavorable. 1 this country our information is very limited, although the qupiu of asbestos used is very large. Its fire-resisting properties lu led to its extensive employment for the -covering of pipes, fumai etc., as well as its use in the fonn of wall plaster, roofing ma rial, etc. On account of its nonconducting qualities it is exu sivcly employed !>v electricians and also in the construction of si. age rooms of refrigerating plants. METHODS 07 MI5TR(J. " Ideologically," accordin' in the Technical "World Magazine,111 best os js a fibrous form uf 'crpeutinc melt, occurring in strata, riysialliiie limestone. The veins run m an average thickness of ut fourth to nnc-linlf inrh, hut sometimes attain to as much as G inch ` " Mining tMtti f i l oui," Of A u ix rf FulUrU ft. la 7 tcUlc*l TYrk! UaattOC, >( - * *-. .'.'ll >J| -I -- t- CCTDTAtlOKS wrni EXPOStTEE TO MINERAL DUST. 177 pi<? asbestos fibers arc, as nearly as possible, crystals of serpentine (. According to the same magazine-- Tlie or is mined mostly in open quarries. Overlying soil, to a thickness of sometimes 20 or 30 feet, but quite often forming only a iliiu layer on top?has first to be removed; and us soon as the asbestos wins on1 thus laid, bare, the actual quarrying operations may begin. Tlie rock is cut in n series of terraces, reaching a totnl depth of sme- 130 or 200 feet. Underground work has not proved successful, ihe upon quarry having been found both more economical and mure cifrt (i'e. despite tlie disadvantages of exposure to the weather. Drill in'' and blasting are employed much the same as in ordinary stone . n:*rn me. When the rock is thus broken up it is rough sorted at the quarry. Two or mure grades are selected, according to the length of the liber, .i.id arc then sent on to the "cobbing sheds," where the further process ,,f dressing goes on. This process is merely the separation of the .In-tvs fibers from tho dead rock, .and is done in some cases by hand, 'a to an increasing extent by machine. Hand cobbing is the very imple method of breaking tho stone by small sludge hammers, throw ing the fiber into one box and the waste into another. This separa tion is ordinarily not difficult, since the fiber lies in layers more or less .afculy clinging to tlie rock, and can frequently bo picked oil with the : I'mgcit. The crude fiber, thus separated as cleanly as possible from 1 tlie waste rock and looking verv ranch like mineralized wool, is i pa'-ked in 100-pound bags, fn which form it goes to the market and the manufacturer. * Hand dressing is not, however, an absolutely thorough method. Tlie waste material from the robbing tables and the line pickings fr.-m (lie quarries have still some fiber in them, and ihc utilization of - tuis frequently represents the largest profits of the mine. All these 5 line pickings are mechanically dressed. In case the asbestos contains , s large percentage of water, tho moisture is first dried out, by ex- pMire to the air, by steam pipes, or by rotary driers, and the rock is then passed on to the crushers, where it is broken by successively liurr-S'-t rplls.. Cylindrical fiberizers and tho cyclone machine reduce tt still further. The latter is the most cfFoctivcapparatus yet devised f"r asbestos separation. It consists of two beaters, one of the screwI'rupvller type, driven within a cast-iron chamber nt a violent speed, tvducing the particles of stono almost to a powder. This is then , l"'sscd over a shaking screen to remove the sand, and in some mills 3 -hong electric magnets are used to take up the purticles of iron. ! In alt of these operations there must necessarily be a considerable 't'CTee of dust exposure, which, however, becomes exaggerated in tho 'pinning and weaving processes in connection with tho manufacture f asbestos yarn and cloth. These processes are briefly referred to in article in the Engineering Magazine,1 in part, as follows: f The spinning and weaving of asbestos have offered many difficulties, __Jke asbestos fibers have no rough surface like wool or cotton, l>ut ___ _____ ____ ___ . A*1-!. .I.d. mlttluv. r e p-a-r tit*io-n . tu a tk tli, a oil w , " 0 K. iW .'fltuao, Cocl* t ^0*1 Oct. 1001. !. l 100311*--IS--Uull, 231----12 f,. U 178 MOHXAUTV FUOM HESP1RATOHV D15SASF.3 IN DUSTY T X are very smooth, and thus have a tendency to slip by one when twisted and subject to tension. An admixture of vrge animal fiber was therefore often necessary, but, while lhc>* luted the manufacturin'; operations, they impaired the fire re of the fabric, and special machinery and ingenious devicr* be invented to enable the successful spinning of a pure ashes*It is, however, now possible to make a singto asbestos thread though weighing no more than 1 ounce per hundred yards, lis strength, and braided material can be made much more re.-torsion and tension, while asbestos ropes, ehiellv usrd bv department, can be strengthened either by interwoven wirtt haring wire-rope core. H 2 A lT H -rr? r!7 B I0 U S OCCTTPATIOHA1 C 0 S D IT I0 1 IS . On account of the rather limited extent of the asbesto^ i in the United States, at least in the large centers of populat industrial insurance mortality experience data are insuifie: definite conclusions. During the period 1907 to 1914 in the l 'r experience there were only 111 deaths, of which 3, or *23.1 p were from pulmonary tuberculosis. At ages 2.r> to 44. there deaths, of which 3, or 50 per cent, were from this disease. dvtst is not described in the extensive consideration of Dust i; by Hay hurst, nor by W. Gilman Thompson in his treatise Occupational Diseases. In 19U the production of asbestos United States was only 1,247 tons, or much less than in carlic indicating a very limited avnilabie source of supply. Most asbestos used in the United States is mined in Canada, and a: lent report on u Asbestos, its occurrence, exploitation, and u; been published by the mines branch of Ihe Department or the 1 of the Dominion of Canada (Ottawa, 1905), which contain scriptive account of mining methods and of the dressing of . by hand or by mechanical treatment, including the final crusi means of rollers, fiberizers, beaters, cyclones, and pulverizers, these processes unquestionably involve a considerable dust hnzr the hygienic aspects of the industry have not been reported ni mny l>e said, in conclusion, that in the prnrtire of Ar.uric Canadian life insurance companies asbestos workers are go derlined on account of the assumed health-injurious condit the industry.1 It is regrettable Hint there should be no further inforrriatior able regarding the asbestos indusiry in its various branches, ing the utilization of by-prodnets of manufacture, on account self-evident injuriousness of asbestos dust as a predisposing c pulmonary tubercuinsis. The subject is not referred to bv 1' >.-rrU.iirr nl ihr r ,n,,di,a ,, * ,, 0 jutrici. ie Uflitaeeflr* to* J o u ru tl, ,V ,, \o r . Apr JU. 191V. nr - r OCCUPATIONS WITH EXF08UDB TO MINERAL DUST. 179 V - eoU Ilan5011 i their recency published treatise on Diseases of Occit- i aad Vocatioaal Hygiene, nor by Sir Thomas Oliver in bis * l\tx>t work on Diseases of Occupation^ The rapidly increasing de t lelopmeut of industries using asbestos, us ascertained from domestic . - vr foreign sources, suggests the urgency of more qualified medical ,,unjiJtration than has heretofore been given the subject. There are ' references to asbestos iu the Index Catalogue of the Surgeon (Jen- 'nais Library, which, however, brings the literaluro of tiic subject l*am'u only to 1800. The discussion of asbestos in the annual reporta i of 11ni United States Geological Survey on Mineral Resources is lim- *. iu.l entirely to the. technical aspects of the raining industry, which 4 ,,nriiig recent years has experienced a rather retrograde movement J mi dut the production has diminished from a maximum of 7,liU0 tons in 1011 to 1.217 tons in 1914. In contrast, however, there bus been a i ^ruinai increase in tlie quantity of the unmanufactured asbestos im- ited. chiefly from Canada. The American production 3 pruc- ; in-ally limiicd to the States of Arizona, California, Georgia, and \ runout. Georgia lias for years been one of the chief producers of a.UMus in the United States, but no medical observations are on : n.-.ird a; regards the possibly injurious results experienced in the , tii.iiitig and manufacturing of asbestos materials in that State. The y tndii.*itry itself has been described, howevor, in a report on the a-L-Mus, Laic, and soapstone deposits of Georgia in Bulletin No. 29 ^S the Georgia Geological Survey, 1914. ' ztcdescts o r bust xxT oatnua I!' relation of asbestos dust to pulmonary tuberculosis is reported at some length in the Annual Report of the Chief Inspector of Im uni and Workshops for Kngland and Wales for 1010. The in- 'Munition was made by Dr. Collls, who states, in pnrt, that-- 3 !flowing up information received from the registrar-general, it found that fire deaths of persons suffering from phthisis had i.i nn-^l j years among a staff of under 40 workers employed k*1. | ln,T " here asbestos is woven. The process wldch appeared 3*' ',:l uangerous is the production of asbestos mattresses. These mat- j which are composed of bags of woven asbestos filled with i mrt asbestos fiber, are placed on a table and beaten out flat by a urn with a wooden Sail, from which process much dust arises, "t-*?? i 5ew mattresscs into sections with asbestos threads Ni l" i i c, 050 to tlie man who beat the mattresses and of necessity *r.['? ^ *he dust. The reorganization of this process with tho nppli, i"n of localized exhaust draft was called for. and an annual medi- W n 7 T ation th workers by the certifying surgeon has been <lnci '.'i in the hope of detecting and removing from rposure to s`10'v,afJ " fly signs of respiratory disease. W Jos" T,:V3 0 r g nn important industry dtinnir tho last 15 rh'cb waT? l^ er asbcsts factories im o visited, rich of in rw.,-.?-nn . 0 ^4Ve '*3 own specialty in the production of which " t y entioa is. required. 180 MORTALITY FROM RESPIRATORY DISEASES TIT DUSTY TRA J There is evidently an urgent need for a more qualified and he investigation of the health aspects of asbestos manui especially so, in view of the fact, as observed in the Scientific can (August 1,1916), that, on account of the restriction place shipments of asbestos from Canada, the possibilities of utiliz asbestos deposits of this country are increased, as well as bee the much larger demand for asbestos products on account recognized value of asbestos for protective purposes in the f once of the industrial safety movement. Of value in th nection is the evidence of Dr. H. `M. Murray before t partmentnl Committee on Industrial Diseases, limited, h to the single case of an asbestos worker, verified as S diagnosis by a post mortem examination. ^In reply to : tion by the chairman of the committee as to whether, id ' the fact " that there is something characteristic in the earlier of dust phthisis in the predominance of shortness of bread, physical signs become very obvious," such a condition h.-. observed in the case of tho asbestos worker under treatnc::: Murray, and under observation for fourteen months, the dec. that it had been noticed in tho case in question, ar.d ; other words, there was a definite relation between the co phthisis and the physical incapacity resulting from the ini , of asbestos dust. It is therefore to be anticipated that the cc of asbestos workers will attract more qualified attention ^country in the future than it has in the past. MICA. No special investigation has been made to ascertain the : less health-injurious effects of mica dust. According to 17.' Thompson the dust Is slightly irritating to the respiratory like dust containing any sharp solid particles, but as a gene' elusion he states that the dust docs not appear to he part injurious. Mica is extensively used in the manufacture of e: machinery, as well as in the glazing trade, as a substitute ft and in the decorative trades, including "the manufacture paper. There are two principal varieties of mica, known as vitc and phiogopite. but whether there is any essential di between the physicul and mechanical properties of the dust been determined. There are mica deposits in some 20 State United States, but the annual production has fluctuated consu reaching the lowest point in the hist deendu during 1914. \ (here arc any special hazards in mica mining in consequent dn-i has not been asecitaincd. The occurrence, exploitation, of mica have been admirably described in a repott published niih';-i blanch of the Depaitmcnt of the Interior ol Canada.