Document wgkkEooDKGDeLek6bj89g54pV

FILE NAME: National Safety Council (NSC) DATE: 1934 DOC#: NSC477 DOCUMENT DESCRIPTION: NSC Presentation by Dr. Gardner - Types of Dust That Cause Occupational Diseases 1934 TRANSACTIONS National Safety Council Incorporated TWENTY.THIRD ANNUAL SAFETY CONGRESS Cleveland, Ohio October 1 to October 5, 1934 The Cleveland, Carter and Statler Hotels Copyright, I9J5, National Safety Council. h;.\ Publication Plan TH E TRANSACTIO NS of the Twenty-third Annual Safety Con gress, National Safety Council, 1934, are published in two volumes. The first, containing: the General Sessions, the Special Subject Sessions, and the Industrial Section Sessions, is presented herewith. It is sup plemented by a smaller volume containing the sessions of the Street and Highway Traffic Section, the Child Education Section, and Home Safety. The large volume is being sent automatically to the Industrial mem bers of the Council; the smaller volume is sent automatically to mem bers who are believed to be chiefly interested in those sessions. It may also be secured on request by other jCouncil members. ' For the benefit of many members who have found it advantageous to distribute copies of these TRANSACTIO NS to supervisors, fore men and others among their personnel, who may keep them for contin uous reference, the following quantity prices are quoted: 1 to 10 copies of the large volume, $1.50 each; II copies and over, $1.25 each. Copies of the smaller volume, $.5.0 each. T H E PLAN O F PUBLICATION is the same as that followed for the last rhroo years. It is a condensed record. The papers of' each session or division of the Congress have been assembled, edited with care and discernment to eliminate extraneous matter and abbreviate the less essential portions, and the concise remainder is presented for study and reference. Although not ''complete" in the sense that every word is reproduced, it is an interesting and valuable record which em phasizes the memorable parts of each paper or address. The original manuscripts are on file in the Council Library, available for additional reference as desired. ' , Although the National Safety Council endeavors to eliminate from discussion at its conventions matters which are not pertinent to its purposes or which are contrary to its policies, the Council cannot ac cept responsibility for the views expressed either in the papers pre sented or the discussions thereon. NATIONAL SAFETY COUNCIL, INC. 20 North Wacker Drive, Chicago I l" i i I r- t: cor Council Officers and D irectors........ Council Purposes and Policies........ Annfi.il Meeting of M em bers............ Annual B a n q u e t.............................. Subject Sessions-- D ust in In d u stry ........................... Fire Prevention in In d u s try ..., Fusion Welding and C u ttin g ... Industrial N ursing ............ .......... Industry and Its M otor Vehicle Maintaining Interest in S a fe ty .. Mechanical Methods of Handlin New W orkers .............................. Poisonous Fumes and V apors.. Safety Equipm ent ........................ Safety Organization and Progran Safe Use of Chemicals in Industr Safe Use of Electricity in Industt T he Injured W o rk er.................. W hy People F a ll........................ All O hio D a y ......................... 1*ERA Safety C o n fe re n c e ................ Industrial Safety Lectures-- Selling the Safety Id e a .................. The Psychology of the Safety Mo Accident Prevention Equipment Manu A eronautical Section ............................ A. S. S. E.--E ngineering S e c tio n ,... Automotive am! Machine Shop Seetioi Cement Section ................ ................. Chemical Section ...........................' C onstruction Section ...................... .. Delivery. Taxicab and Bus Section.'.".' Food Section ................................ Marine Section ........................ .. . . . . . Meat Packing, Tanning and Leather Ir M etals S e c tio n ................................. Mining Section .............. . . . . . . . . . Paper and Pulp S ection.................. Petroleum Section .................. . . .7 .7 Pow er Press Section...... ...................... Public Utilities Section........ . 7 7 7 . 7 7 Q uarry S e c tio n ...................... R efrigeration Section .............. R ubber Section .................... Safety Section, ARA--Steam Railroad' s Textile Section ...................... I ransit Section ........ ..................... Wood Products S ectio n .... ... in d e x ............... .................. National Safety Council . Incorporated HONORARY MEMBERS ;\smk l.Mlt'N lIF livi.N ,\SI> S'f'l.FI. Ft.1CIItH'.M. RmiKitr W . Ca mi-uku. A rthur W illiams PNO!NLEK) OFFICERS (1934-1935) John K. Lose, President. 1 Ui.bi-.ut . C.vrux. V ia - President for Public Safety. 1). I). Fk.nnli.l, Vice-President fur Public Relations. l,K\v R. P.m.mtk. Vice-President for Safety Councils. A lbert S. Rentla, Viee-Presiilent for Engineerm. C \V. S mith. Vice-President for Industrial Safety. 1R. T . S olknstkn, Vice-President for Membership. . >k. C. t i. W atson. Vice-President for (Health. A . W. W iiitNev. Vice-President for Education. W. W. K11. . Worth. Vice-President fr Finance C ameron, Managing !Jin-dor and and Treasurer. Secretary. EXECUTIVE COMMITTEE (1934-1935) 11 A . L, A rmstrclat., Kastman Kodak Company C. . At:t%, Past President. J . I: B axa sh , Past President. . C. W. HfiKtH>tltST, Past President. F. W. Braun, Wood Products Section. W. H. Cameron. National Safety Council. R obert W . Cami-hell. Past President. T . H. CakroW, American Railway Association. . 1 ' Robkrt I. C atlix, Aetna Casualty & Surety Company. J . E . C ulljnev. Bethlehem. Steel Company, I. F.wis A. DeB iois, Past President. Marcus A. Dow, Past President. 11 D. F ennell. CmtsnUimt Engineer. 1 1 . .. F en sem - Kansas City Safety C'tnimil. C apt. E . W . Fiskk. J r.. Marine Section. R. B. F otitujn. I-ehis) Valley Saiety Council. II, mu<v Gun.nKHT. Tlie Pullman Company. Merle C. Hale, Automotive ifc Machine Shop Section. G. T , I I f.u .mwtii. Chicago, North Shore & Milwaukee Railroad t . Hon. H arold G. Hoitman, Street & Highway Traffic Section. T homas P. K earns. Industrial Conunission of Ohio. W alter G. K inc. Past Prrsidcf* 4 I c F ranklin M- Kmlml, liiaiist John F. Fono. The Delnivare -Ttios. II. MacI W .u .i, Unite. K. }. Me:irkn. Portland Cei. I W. Mii.larh. Accidem l'rt-t L H am.i.ii 1.. Minlu. K. i. dii Poi Ar-i iti ir T Mokjv, Past Pres l.i.w. K. Palmi li, Past Presili 1 `. li Pi t iiir.nl. Past Presili f . K. Rai.siu n , Western Peni. i , \ i.i:i itr S, K'koim.a. Industriai i l.-r. fot.. 1!. A. Ukxi.nih-r. 1' * Iil i-oi.t. li. S ani am, General I k'oiM'nr !.. 'h -u n irr, l.ntiisville H arry* A. S e iiia .iz , United S C harles 1. Sei.fr, l 'ast Presi l.r.sTiat T). SiiVMOfR. Acronant f . \V. S mith. Standard Oil ( W alter I"Ji:st S mith. 1telate: R. T. Soi.KNVfEX, Militili Sei- t.'i.Ato m i : P. T avi.hr. Massari l'. P. T oiman. Past President .1. A. Vnss. Metals Seelkui GMn.r li. W vriti.. Union !'; I ir. t'. 11. W.MSov. Ann-ricav A. W. WtiiTNKV, National R. \V. li. \Vi.im i, inlernatiiaial \iiiiiu n l i. Viifxi;. Past Prc D IR ! l-'i,i i.ianeK A rcher. Cliild Kd.. W illiam F. A rim.rn. Satety A. !.. A ummir.no. Eastman K W illiam 11. Baker, Quarry .1 I. P anasi!. Consultili" l-.n; II H. [anta. Paper & Pttlp liiiNrsi W. P.f.ck. United Stai W. A. Benni-.tt, Worcester S: f . W . I!t iicoeisT, Western F I n .n i S. ISemu, l.theriv Mnt li. F. Bi.ank. Jones X- l.niTfihli f F. Bhuki nhaoln. Keiioslia F. W. PiRVt'x, Wiii.d Prodnct I i l.. Pini. U. llunCKUAN. St Phi.-tmn I). i' ai.i.i'-m, Batlmoi W. 11. ( `ami!,:;. .Vatiima! Sai T. .1. fAUNl.v. l inea"!) Sait-ly T. II. Cahi.i.w. American Bai K / Uvnty-lhiril . {,,at Safety Couyrrxs-- Xatinnat Safe! , ( l5"' 'I' S pi.zma.v, Troy Safely Council. Ai.ritr. H. S u avn-k. <.moral Motors Corn..ratio,,. Ci..\uk.\ck P . T ayi.oi;. Massachusetts Safety Cotmcil. Artui'k M. I III,,;. Ctitlsultii," Marine I'.naincer. M'. W. T uf.ntk. Schenectady Safetv Council. U - 0 . Tt;nm:vtu.K. San Antonio Safety Cotmcil. * ^ Metals ScctitM*. H. A, \ \ ai.kkb, RuMkt Section, Gforoe If. W arffx. Uniott Pacific Railroad Con,pane. m p!;.AiT V ! ' XVAn r 'V'. \'m'riC;m T c k >,ll""'-` * TeleuraiJ, Co,,,,,anv. V ARR' " " . Illinois Jidi Telephone Company. ' Ai.bf.r t C. 'White. Jit.. SprinpfiL-h! Safety Council. S. h . \ \ inrts-o. I.iherty Mutual fust,ranee Company. \'V 1h1' \"vtN,"AITXNSK.V'Lr-iXtt!oltni,H('.aairln,i.oIerc&a" CarbConaCnorVp. & Surety Umlenerifcr,. ,,* C-'I'~ A- Wtj.-M.ow. Vale Medical School. H arry \ \ irk. Sr.. Chattniioopa Saietv Council V""K!il0'VI> Sheet * Tube Conipnuv. U . h. UORTH. International Harvester Company. p J- Sm"L'ty I5" rCiU'- D" ,,ith Chamber of Commerce. ir ,>lv- sr~ ~ ...... - * ... -  anal ', to put * (Hlficil rennrs oi ti.e . to lay be* <> developed ; ! action in logram for ' cates and t from the 'S . 1934 . in session >gs and my you are program to ady taken It, because ' with the c solution citizens is -mg toll o[ grim that hway comtire, and nl disaster, lend your . ".ion with upon our . ,i.T. Hoffman, uisttnastcr. >. of New -urpassed,. America.' dar mono- evening: me Council T i r U X T V - T J H h` l> .7 A' iV l: A 1 . S A F E T Y C O X O R F S X X A T I O X A L S A T /: T ! ' C 0 X X C t I. Dust in Industry . FRIDAY AFTERNOON SESSION . October 5, 1934 7 he session devoted to a discussion of Oust in hxlm trv was culled to order hv P.f: >" *' Meiler. Director, Industrial Hygiene l-aboratorv. Employers -Mutual I.ia- Inhty Insurance Co., Milwaukee, who presided. Dr. -Meiter briefly welcomed the delegates and then introduced the first speaker. * Types of Dust That Cause Occupational Diseases By L E R O Y U. G A R D N ER . M.D. Director, Saranac Laboratory for the Study of Tuberculosis, of the Edward L. T rudeau Foundation. Saranac Lake. N . Y. 1 he speaker raid in part: Experience has demonstrated that the him* tU-nes can toleraif very large amounts of most kinds oi foreign dust particles without serious interference with function. The lung may he intensely pigmented be colored dusts with no evidence that respiration is impaired, lin t dn'rts composed, in whole or in part, of silica have been shown to be dangerous because they stimulate the growin m the connective tissues oi the lungs and bring about the formation of scar tissue, 'ib is destroys the normal elasticity of the organ which is necessary for respiration and it thickens the delicate membranes so that a tree interchange ot gasses is impeded, fortunately, these results only iollow the prolonged inhalation ot very large ipinnihics of silica. ' Experiments have ^demonstrated that the inject ion, oi >iiir;. into the ti-.*-ur> .it inim-ils kills the cell' where the substance [tges and ever.*' an intlaonnat-n. M he?' healing takes place a very dense and characteristic kind of scar tissue forms. Most non-si!io,..-,: dusts produce no mdamuiation and very little scar. It has keen shown that such changes do not follow the injection of silica unless the particles are very tine, three microns or less in diameter, and unless enough of them localize m one area. W ith larger particles the rate of reaction is so slow that little change occurs within a year. As a general rule, the finer the particles, (he more rapid the cellmar rcsjnmsc. '1 he reaction to line silica begins within four or five hours and it continues for a period of years. If the silica is combined with bases in the form of silicates, it rarely produces i such active and _progressive changes. The silicate of magnesium, asbestos, does ' cause the formation of scar tissue in experimental animats and in the human h u g . lint tn<u4 other silicates are not generally recognized as irritating. Recently it has been claimed that a hydrated silicate of aluminum and potassium, called "sericitc is responsible for most of the cases nf silicosis. This silicate, a transformed feldspar! is oiten associated with guartz ami it lias been identified in the lungs of persons sttf- 23 U / W ttty -i/n n l .-hmual Safely C'ouyress^Xalitmal S a fe ly CaaneU are still in pm-cess Kaolin , i 1` -' characteristic d u m A s in tit' 'h .n R s 'A r A h h iu ' n -t perm it us 1.1 assume that silicates -is a e h ' Mi>M observers now believe ih - it ' im r ml '' S i the tissues because it is slow ly dissolved ,,""h o m ajority ,.f experim ental observations A cult to understand hmv cmiush o f s,,<di an i h * ' * 1'nvc tailed cxcnc '.NJ'crmicnts w ith this -t:',stance `r . 1r ^ ' 1'* nlSl', 1>r' " i" cc'1 flt,ite ,r l ' rt*'toiit hiinwlc.lec docs l *p *)ruibice crimis tissue nainaac. fh b k o7 tl7 T V ` S ta ,h i e^h .11'1-11"1lrj>'` ,1,t1',5cr!15;ln,,>' '` h'ihiie- d ts s o lm ! w ith in eml.i hours to produce 'i vc -,,a T as. ,|,"n n z 7 1,1,5 7 soltil.d.ty were the otdv factor ,.,, c should , A w A A ' ai' ' " c . ii the injectum o f the more reatlilv soluble silicatA h.n - acUve , rc f,',,|lfc i<r titerly it was held that illA L 7,1 fnch is not the case, Fnr- <|twrtz particles were believed to Cf,,CCt ,"*-`c.!>nm c:itly . The hard sharp tion .,f .scar tissue as S I A , , - [l' l'! : , i l!r li'r e i tor when animals arc injected ith' uther hard'~ l ru.td.nn or nlumhmu, k A fi o ,l"'sl;U7 t a 1,0w r ite the forma- .A huteer tenable lice dinmotul. caFho- aMnlly ttuiberrcualouSs iuJiccti&un. t S : ,C susccl't,hli|0 ^r*` tnrc hrnif*f to miecuon. espe- come out to tak e' itA'ip AId".IVA ^ !lvj lTa'VrteCpte^ttitiAiomn lamr 7 ltth^is''"n"nl uS-em`rnl...n..v..wi. I.'l_w__cocc-y,tcw accumulate so that many of (hen `incest nuk " f tl,A 7 ' ' CCS\ . cnnl't:l1 I'Ikwocvics Mat,res thc stimulus fe J " A o A h ld . l 7, m ^ 1 " ,llr Muh rritm - of the cells. They na.,,r:,nv ( " m l ^ | v c ' Im l l .7 :T iy "T 'Utility sils and accumulate ft |vmih iindt* t m ' m le r (be lymphatic vvs- the inihicuce o f the irritating siliA ..,',,1 l-ere 'A A m `A " '" " '"re rapid under arc ronsc<|ncJly localized in im* nodes * *tstib*rn>lc numbers m particles mrM / a , s , :; E A TM ',t.,uT ,1;", r t 1 in such an extent that the ikmIc is entirely replaced lw a ma-- `f C rca,'tl"1', `W'-clnps tissue fihres, i.iten several time a I ,re . ih,. 7 , fuarse. plas.-y scar croach upon and compress the ['emphatic A,. tVA ? S '-' "duics cu ts choked and effective removal of suhscouemfe 1 . t , rull,.'*;<' \v.tein ot the lttn<r mDustthisnolo- caaciicou,,m. ulates around the I*vm1ph' v' tes*iuel' iiid 's'h`A`-trs,Not? rsacfa,urn,tii>s*su'lie'nudueVvehleodp. o n l j 'dm l n S h a ^ s l c . A ' - n ; ; T c A , A ' - / -voKo ill eoud Mem X-r;iv liims tiiC'C preluiiinarv'cle.iT'11'5 i""* -or.-o-d. cninc and headimr of the shadows cast hv the 11 "7 " i:i}' 1 lr v,sl!;lIl,:v<l as a thick- * ' 5l,<-` shadow of the.root of the Iuuk The h h A w A d ' ' '"01 ' m 7 `" ' the most mijiortaul lymphaliv vessels e n u rs /th ro ih tlwTr d'is * ' 'T ' 'o 0'1'1'"-1-' due to the mnmle nodules ,,f silicotic s.-n- ik s n ,.;' Vi. i \adina ts ham. The root shadow is wide A heeause r " ' J C. . ,-v,,*l'h .no,lli: "'">> the nodes i,, ,1ns |,.cation. a a " S `,f t,M s,1,c`,,,,: rt'tvt'" m the lymph t h e 'l y n S w sA -i:!^'l lA i h a e o m m Often the veils roup tl.cmselvA h. mlnlJ 7 ,.t ,"i-,hC u ? ,k these hicatio dm silica aeain sti. tih u ' ti-. f *hc>' ? rc w wee*, In VVtth the tormation n( sihVn,ic nodules in the functinuin* |)arls o( liu. !unp tIle ' ' Cinun.Y 'tiled io Cx.-i:c this sui.>i;,j!fc n 'Tniluroil i(tiuc mowtedce docs' (issue damage. ' ; POlSOllotls l.i t-'eriaiiltv the >1 it is'diiri.:ortz could |.c (minatinn. If response niter d;e rase. i-'.ir_'i' hard sharp .'itc Ihc forma- lunger lennhle amond, carhn- no formation -ilica is due to =ts which are `Iiavior fif tile nodules oi scar infection, espe- tfiis irritating phagocytes eh phagocytes r such circuits!,'i tile motilitv hwnpliaiic ves'* rapid imilvr* . ' '**' partidus 'narked owr* H*tnm ilcvd'tp'i ^r* classy .car '* ifcxlulvs on* f tile ttHIt* dly ttimmi>ijvri. I^SSHC develop they involve <lly affected. I. as a thiclcitli a. widi'itveiled hrcansc <ic heading is ls within the in the lymph ' *1 off through die air spaces. 'Caltcred. In The result "tt'throughout wilh function he air spaces Male and their i -also incoiu- the lung the . ' ( . ^ / ' . 1 , * ' . 1 t . . ' ' i ; j I'"si in / mlnsirv 25 round shncl-ws.' AsTm.TTnTV:"',- i n "1, ^ ''" ^ , l' 1.1" ' s"d l >1 clear cut. accentuated In te r ,,h.-oWs of ` " T u ' i,/c lll,7 ,i," t <"" `he helds may hu thickly seeded wiih Inm.l,- . |U s'-t s' , ", " Wl'H marked case l,||, lllnb tmlldd_ ,Hi>l'i'e>' H- iinWt llaLtT,[<.:ea,rlslmh'lac'*k. c-l-hv'icmn ' Tipm a- tT lu,K" Th-i's1'e1s'. <"l'-"'fiumcda.rkrionugnsdeadr.e nvoidsuiblaler J'he condition of silicosis .. .... , a mail has left his dusty m in m i,, w ' TM -" c ami it mnlimies to ,level,,,, a,-tcr loaves with mam- ,,odul-s T ,'.. ?; " .....' "`wowr. when " ' 7 >cH..ce important^Vnneilmtar c T ^ n u n i > r " d ! "*"? ""-. vase in si.c only a lew midulvs situated in the V- f,l''"'iisly the ecmhnued growth ot *'"T he 1" ,^ S!" U nH,M i,are UUh ^ e c t may arise from rc n c tiv n ti.m ^ ^ by tuberculosis. This a new infection from without. The ,h , ., ! r niecinm or .t may result from ot silicosis present. The course ,,f , I c infeL.,, r ' ami it-.n u n tails t0 ,,r<,diice d n rm m rT .v ` -'c with the amount usually chronic onset. Many times it is ace,dent'-dh d e "r months or years' ain-r its Krotips of active worlcmen. liow . ver , , ! ' u W - r'),'t.,MC X ' ^ y examination ot in silicotic individuals with inficlion ti. ut M h o T '. ,.l"ii,l" Ilt-v -'re nmcli more marked stonally tuberculosis may run a '-ere \\u h uncomplicated disease. Occa- Also true in other perMms T le cmKe Z ' T su'>>TM >> this is tuberculosts is not perfectly .ler I m V ir T ' ' ' . t` ' ,ty ` 'f, tl,C silicntir '" H i to M >ca on , lc tissues creates a " h ,r hie f ' 0 '"' lhat; `,! "< the 1 he tttltcrclc bacilli nmltiplv :md a X u I v n n . l l h. ' . trm vth ? t! bacteria, the usual clinical symptoms tuberndosi's i r , . n 'i! t !I,!`K!W r,ci,<:t"w ensues, hut time because the dinuees for nbsf.riuion held m abeyance lor a Inn I1"? 1 hy the obstructed tv..,.L ie vu I T T ' d infection are mini- limsims may lx- absorbetl on tbt 'il i4 ,, NV| .c ", S " ' ^ . v c of these ...................... - ,i I>bmma? S n j ^ '*'!%'! ;i" TM,^e of severe tipper T esphatory u , e ! i h a 1 i ! L i r S ^ , " t ^ sueh librcs and even quite lone -lies unv nen T'r.t'''c'*A1 w ar tlk`. i w ^ " 1,)* inbalatiuii JtoUe.w'c m:mv Ihvsq slriictures have irregulariih-s i,, I'hrlr ,, m '' i"' !' 1,0 l,,K`r bronrhial tulios:. dusts. vyles. I1nhetinc;elllosca,t1i,,onlmtthe,saersmhestos (nca`riicTes ar. o . J 'i T l'" \ M' ** hbrons Cr<m'h'<l and mgestefl hy pi, eially immermis n,,r do thev tui'rate rat.i.ll.- m. `r they are not esi>e- eytes deal,ug with .ptart/.. Apparcntlv 'most" , f 1! C :` s, ,lll; ** " i phago- iraements directly into the walls . f th. ttme dust sets tip a p ro lite rn L T, 2 -``f - V ,ltt`,r hiirtlen of ashesim ,lhT 'c. The tnildlv irri- tiiK in collar-]:!to ilm li miq. ,,f ,i,.. l f s"5 Vl:ll> the alls r.-ml;. narrows or closes the ml- and Ihcn-liv ..hitis 'inr "in "* " !C ,,C'V `vl' IUtl>'v tiwuc peripheral air spaces. These spaces 1 on e h,,s . :,ir ' Uw m,,rc l.lus m .tsvl. t s a cause of fihrolis ,',r so;u-r ,,c o i,,; / , ; ' ' 1' ,V ;''<nV'' ,n?\ ;dolc,-tasis. o numerous relatively smalt ar,-,s in it,. L , , , `' ''ssue. i he result is a fibrosis rihro>is about many small terminaV bronchh] tida-s "T h'. \[W ^ ,l'? r' 1'1>e emistricling play httle part in disposing of ahcMs (hut (lust arc ifniml in tlic lymph nodes. '* '""h-- lc s-vslcnl ffcills to msigmiicant amounts of this prcvalcnrc.'of1t h c 'b u l n e ^ l m ^ 'o * h^nchnp.wm.iniiia hut the Surveys ot.largo groups of ashesp.s w .rbe?s foil . in silicosis, tuherndosis as found in similar studies on\siHca ?vorkcrs MKh " ,IB,* i"'-'h!vicc of ducc sieni,1canta 11era";!ois'1"!!i The h'li^0' ItjV o f ^ " t,USlS r i : ?i,,!ia r?nl,y z ^ fa!,s to zl'n'- The cells are nut stinmlatnl Z , 2 c y L `1,C casc nf nuarla. them remain within the air sp1 ac*"(es fmorr aa hlo.nnTg tiim. le. Sqome, apacrotnicsucflpairelyncethomsaenycono-f Twenty-third A ,m n ,l Safely C o u ^ - X a n a u a l Safely Coancil denned il1]t| SI,,)U)(| rcwjve ,,iAi! <rr i ; : i r r 'l,',S|materials arc [css cicariv 1ms k e n done in th e in s t diat ihr ',? r !t sw,n lll|we to assume. `Mwnt* And that rmlv lm n Mr 7 r, n,nr ? ,a 'W'?t * * '* "* * -T only as inert m-mtal awl clinical data a r e ^ . 1 * ' " lixpcri- <;;sts may materially modln- the ac(i; `, ^ lh.:it :,t k-ast some other nodular liornsis in the limes ami to h i c m V tb?*' W -lts cai`;`cil-v to produce mm,,1c. animals i.halim; k a v v c.mce urat , fl ` 'w u io sis. For sdica and hematite iliist for c id S ^ L a mixture of crjual parts of pure ihnvti not evou the inillrnf? * * **' #<HV* ** l,cri'*f of 14 months have pure quartz dust, inhaled for onK- tu o 'h o u U 'T d av t ' f ' h<: '" 'f t ''vh'-'rras a;#0 seems to he true that animals ,, t , iJl i <ro'l,ILCS dtlmitc nodulntnm. It iv tuiw ct.li,sis than , | U ` "" f t TM arc much less susceptible miner, tune Jmii*s show definite sdirr.iL* i 1 lc ot tiie iron a..-i many no .mdules at ali An ^ V l.i? ^ ,f',lu;rs a vcr>' 'Whiles cc.Iular connective tissue reaction `w hen tiirV ' / ''`r ' ^ 01 ,ri?' l,art,cios with a chemical analysis of the h. m i lnes v u , , cau ^related will. ::,cii t!.ee miners have P ^W n n 'd . 1 a|il'r,,,';.''IK\,c amount o! rode work si.xa and tlu- tihrous nodule io rm a lL ' n a v k MKIt " ,c. exp.urc to iron miners is apparemlv ie prevalent mtudV 1 . * 1,1 t!lt'sc t" l-'-re silica. What 1ms hetai s-i . V . . - I.C'n severe than m men exposed u -rk e rs ami coal miners I, U t m i v l " ! ' ` T ,!* f11* ' ,n '1' <`dr> nave less tnliernilosis than the a v eri-'-'i'n r V l--^ Ul ,-"c!' *" ,iw ,alh'r ''ccupatiou they have the meet,on hut that i t t \ li'st it CM*n*t*s ihnuno^rs a * 14 t v ' " iwniftii in its imiimcMatirius c .:.m O ! i, htr!'e 1 m , ^ o M r ':" l dl':! !'" **** ,'**? W* these sniotanet-s behave atypicaHv and "in' in i''i* 1,1' ? - * m compiieatimr infection. `The same `,ln v ss s more mieusive stiidv to ciariiV our v:ov-s ..o 'i:i',.''t!'"i'm,t certain slates and rauhe lc;a" - !'-x|>rriniemnlly r S t t 1`brosis tmicss there ri'<'**iv<- much Using Exhaust Systems and Respiratory Equipment To Protect Workers Exposed to Dust . By STUART W. GURNEY and DAVID S. BEYER Liberty Mutual Insurance Company, Boston d T S ' 1 "horrtl - ; w s \ c r 'a 'Cr l Ur S' atCS ,UV, !,a<1 r e f e r , to dust .krone!,Iv a,forced hose h s T l" S ? 1 bnt sta`c * yet =* * s s ^ - & ^ i & =?3