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FILE NAME: Union Carbide (UC) DATE: 1935 DOC#: UC002 DOCUMENT DESCRIPTION: Excerpt - Transactions of the National Safety Council - Silicoisis and Silioc-Tuberculosis Medical Problems of an Important Industrial Disease > . 1935 * , " TRANSACTIONS . ' * f ** *** - National Safety Council Incorporated TWENTY-FOURTH ANNUAL SAFETY CONGRESS Louisville, Kentucky October 14 to October 18, 1935 The Brown, Kentucky and^celbach Hotels Copyright, 1936, National Safety Council, Inc. Foreword ' HE TRANSACTIONS of the Twenty-Fourth Annual Safety Congress, National Safety Council, 1935, are published in two volumes. This volume, first, contains the general sessions, the special subject sessions, and the iustrial Section sessions. It is supplemented by a smaller volume containing sessions of the Street and Highway Traffic Section, the Child Education -tion and Home Safety. All industrial members of the Council automatically receive the large volume, e smaller is sent to members believed to be chiefly interested in the sessions :overs. It may, however, also be secured by other Council members upon uest. Many members have found it worth while to distribute copies of these msactions to supervisors, foremen and othprs in an administrative or superory position who may make practical use of them for reference purposes, r the benefit of those who desire extra copies the following quantity prices arc oted: One to ten copies of the large volume, $1.50 each; eleven copies and ?r, $1.25 each; popes of the smaller volume, 50c each. M ACCORDAN'CE with the plan of publiIcation followed for the past several years the Transactions are published again this year as a condensed record the proceedings at the National Congress. The papers of each session or Vision of the Congress have been edited carefully to eliminate extraneous matand to abbreviate the less essential portions because of space limitations. In :nr words, the material herein presented is not a verbatim report of all the eches presented at the Congress, but rather an abridged version, made as mpact as possible, yet without any injury.to the technical aspects of any Iress. The original manuscripts are on file in the library of the National tety Council, where they are available ' for additional reference. In several es, where illustrations were sent by the speakers to the Council, these also on file. ' The National Safety Council at its Congresses seeks to eliminate from dis,sion matters which are not pertinent to the aim of the Congress or which arc -trary to Council policies, but it cannbt accept responsibility for the views pressed either in'the papers presented or in the discussions based upon the ;>crs. NATIONAL SAFETY COUNCIL, INC. 20 North Wacker Drive, Chicago CONTENTS Page Council Officers and Directors........................................................................... 4 Council Purposes and Policies...................................................... j ................... 9 Annual Meeting of Members.. .....................................................! .................. 11 Annual Banquet.................................................................................................... 27 Subject Sessions-- Finding and Correcting Accident Causes....................................................... 29 Fire Prevention in Industry............... 33 First Aid and Health Service in Industry.. ................................................ 31 Heat Exhaustion............................................................................. 61 Industrial Nursing....................................... 73 Industrial Safety Lectures-- Public Speaking in Safety W ork................................................................. 79 Selling Safety in Foremanship........................................... 89 Industry and Its Motor Vehicle Problem.. . . , ....... ..................................... 103 Maintaining Interest in Safety..................................................................... HI Occupational Piseases.............................. ...................................................... H7 Safety Equipment.............................. ............................................................. 133 * Safety in the Small P lan t.................... .......................................................... 145 Safety Training......................................... ............... ...................................... 147 Accident Prevention Equipment Manufacturers' Section............................... 153--- Aeronautical Section............................................................................................ 159 A.S.S.E.--Engineering Section........................................................................... 187 Automotive and Machine Shop Section...... .................................................... 189 Cement Section..................................................................................................... 177 Chemical Section.............................. ................................................................... 193 Construction Section............................................................................................ 209 Food Section.......................................................................................................... 223 Marine Section..................................................................................................... 237 Meat Packing, Tanning and Leather Industries Section.................................. 265 Metals Section.............................................. ,.........................................................283 Mining Section...................................................................................................... 301 Paper and Pulp Section........................................................................................ 321 Petroleum Section................ ............................................................................... 345 Power Press Section............................................................................................ 373 Public Utilities Section........................................................................................ 391 Quarry Section..................................................................................................... 411 Refrigeration Section................................................................... ............ 423 Rubber Section.................................... .............................................................. Safety Section, A.A.R.--Steam Railroad Section, N.S.C................................... 459 Textile S e c tio n ....:......... ................................................................................... 485 Transit Section................................................................................................... 495 Vehicle Fleet Section............................................................................................ 513 Wood Products Section...................................................................................... 529 I n d e x ................ ................................................ ................................................... 537 126 Twenty-fourth Annual Safety Congress-- National Safety Council under controlled and uncontrolled w orking conditions. It is apparent that where some m easure of control is practiced by such utetlmds as segregation or local exhaust ventilation, a m aterial reduction in th e cx|*Kurc to m ercury lias been effected. I t Is o u r beliei th at in th e ca>e of tlie b lo tte rs' c\|nsurc, a reduction m ay Ik* effected by m echanical enclosure and local cxliaust ventilation, ami tltat tlie shippers' exposure to m ercu ry va|x>r m ay be lessened by a general system <>t vcntilatnxi sufficient to ciu n ec tlie a ir in tlie store room frequently enough to brim; tlie m ercury couecutraIratio n to a low er level. U nfortunately, in tlie present investigation, it lias lx*en ini* |HK>ili|c ti liml a plant in w hich a n attem p t l u s lie n u d e to reduce the exposure for these tw o occupations. l u som e dusty occupatuxis tlie m etliods ot controlling dust have nut liven leveloped. In fact, operations such as removing tlie cores from very large foundry castings, sand-blasting, lum lliug of used storage battery plates, paint chipping, anil cadmium oxide m anufacture appear to offer nu practical means ot ;ulo|u:itcly controlling the dust generated. In such cases, it is llwreforc necessary to furnish the worker with personal resp irato ry protection devices to prevent his cx|MMire to the lianniu! effects of tlie dusts present. Tliesc devices consist of various types ot respirators, masks, and helmets. I t is im portant to hold in mind tlie lim ited use ot pcrsoual protection devices. Because a w orker cannot with comfort w ear a mask or helmet continuously, such devices m ust be employed interm ittently. T heir use is generally extended to those operations wlicrc all other m ethods liavc failed o r supplementary to them, as in storage battery repair where the exposure to smalt amounts of lead breathed is known to be detrim ental to liealth. I t sliouM be pointed out t lu t th e l '. S. B ureau oi Mines is *juipi>cd to conduct approval tests oi respirators used for protectm against various dusts and tunics (S ch ed u le 1 ). T hese tests a re conducted against the diM for which the device is to lie used am i a rc rated , not uu an efficiency basis, but ut the quantity oi lust which actually liasses the respirator. 'I Fie results o i a study m m asks o r helm ets of tin* p*isitive prv<Mire iyp\ in.uk* d u rin g the sandblast invesiigaliou conducted several y ears a g o by the Public lle a lili Service in coo|K*ration w ith the N ational Satety Coumil.* shovved tltat tlie mil y practical safeguard to tbe w orker insile the sand blast room was to provide bim w ith a m ask o r helmet oi the positive pressure type, lu studying the efficiency of such ilevues it was ioimd tltat a relationship existed betw een th e am ount o f a ir supplied to the helm et and tlie concentration of du-st iiisidc tlie helm et d uring blasting. T o determ ine die optim um a ir volume to be sitpplieI to such protective devices, it w as necessary to obtain dust samples from inside tlie helm et while varying the a ir volume, at the same tim e m aintaining the dust con* cen tratio n in tlu* sandblast room font side the helm et) constant. T h e positive supply of 6 eu. ft. of dust-free air per minute will protect a worker under the operating conditions now in practice in 'au<l-b|,*w rooms. T h e ultim ate criterion of protection, however, is the rc-u tt of d u st determ inations o f the air w ithin tlie helmet, th a t is, the, a ir actually breathed by the w orker ami not the volume oi a ir supplied. T o o much em phasis cannot Ik* stressed on die necessity ot m aintaining in goM| o rd er die persoii il respiratory dev k es for tlur protcctiun oi the w orker against various toxic dusts. M aintenance of exhaust vcntiluliou systems, and other types of protec tiv e equipm ent, should Ik* a rule in industry rallie r th an an exception. T o o often die term ``good housekeeping" has Ik*cii in terp reted a*s signifying only the periodic removal of dust collected on Hours, rafters, etc. Although such practice contributes to the general state of cleanliness o f a w orkroom am i should alw ays lx* in force, the time lias surclv conic w hen serious atten tio n should lie given to the installation and rigid m aintenance o f all types of dust control leviers. In every plant there should be some res* noble individual charged w ith the periodic inspection of all workrooms as to sanitation, ventilation, and maintenance of all dust removal and other protective devices. fV rhaps the best criterio n o f flic effectiveness of these devices is the periodic determ ination o f Utc d u st content of tlie air at the workers* breathing zone. O nly by constant vigilance and an approach to tbe problem as outlined in this paper m ay one lioje to m ake progress in tlie control o f the dust hazard in industry. O ften the benefits of even a most extensive program of dust control are not immediately realised. T h is is especially true in dealing with fibrosis-producing dusts in plants where some of the w orkm en have already inhaled sufficient quantities to 4. Occupational Diseases 127 cause disability. However, in dealing with such dusts as lead, cadmium, and mercury compounds, control measures may produce salubrious results in a relatively brief period. It is difficult, because of lack of sufficient reliable data, to indicate Iterc the economic benefits resulting from a preventive program of dust control. It has been estim ated by Dean K. Hrumlagc, statistician of this office, th at the minimum e.\|iectancy in savings to em ployer ami employee from a n indicated reduction of tlsc accident rate and oi die time lost on account of illness ( o r au equivalent rctluction 11 m o rta lity ). dem onstrated as attainable, is $20,000 p er year per 1.000 employees. A n d this estimate is for plants whose accident rale is considerably lielow the average, in which thena re no occupational health hazards. In plants w*herc hazard s a rc known to exist the savings should he far in excess of this conservative estimate. W licn one realizes that in this country there a re approxim ately 15 m illions of w orkers engaged in m anu facturing. mechanical, ami m ineral industries, then it is evident th at tlic m agnitude of the problem has not been overemphasized. References 1. ItlonmiteM. J. J. and |)res*cn. \V . C .: SilicuM* amawe g o i i u c <|iurric . I'iiN k- H ealth R eports, V'ol. No. 2), June I, IW . 2. A n ih raro-S d k n si a im n c liard ral m iners. Public H ealth llu lletin N o. --l. I'M). J, lilouiiiliekl, j . j . . an d lirc e n ln tre . t.c<oiard:k S a n d am i m ria lltc a h r.o iv c Id a sim e a% an in d u s tria l h e a llh h a z a rd . jHir. lu d . I t ) .. vmI. IS, no. 4. J u ly . M i l 4. H atch . T lito k ift, Drinker, I'liilap. and Clioatr. Sarah I'.: C m ir d o i the sili.' lia/ard in the hard-ruck industries. I. A . laboratory study o i the d eo in t <4 du>l rooiriJ trios lor u -e n u ll |>neumaiK ra m ie cu ttin g tmJ. Jour. I11O. 11).. vol. I*. no. .1. M aul. I'u. | | , i , h . *llicodir. K elt*'. t.corKe S .. and t-'cl-ocl. J. W .: C mui-4 <>i the -ili<! h azard in the lM i>l-tk u id u -irtev II. An inve-UiKatnHi >>t the Kctle> >lu>l trap l*r u.^ w ith |llrunlatlc ru'k drills 1 the "Jaik-haitHner" typ e. Jour. lud. 11.. vol. 14. 110. 2. I v lu n .u v . l'iJ2. Hats It. Tht-odrc. W .iircn. Ilvury. and kt-llev. I.vorce *'<011rJ nf (lie - i l i .- . i iiazard in the hard o n k industries. 111. IK-mkii am i o t ia iio ti o i a iu si-i.m tro l s> -tem i t it-r with pneum atic M k d u lls in ot<n excavatim u Jour. lud. l t S , vol. II. no. 7. S cficm o cr. 1'U l Silicosis and Silico-Tuberculosis Medical Problems of an Important Industrial Disease By E D G A R M A Y E R , M .D. N ew Y ork City A hidden element of the cost of production is industrial disease, industry has reached a stage In-yond the com erii only oi w ages ami hours, 1-ar m ore iiit|tortaiti is eoitservaiinii of man |m w cr hy preventive medicine and improved engineering. Disease p m e n iiv e mva>nres are not a cot. hut. in the long run. a g rea t economic saving. htc:ii,i\ft\ In the United Slates it has U en cotnpnled that there arc from 500.IMM to a I.IHMI.UKI people cinpl'>et| in oecut-atidiis where a dlii>sU L iz ard exists, in New York City ilterc arc about <'5.000 stu b employees. In a rep resentative group of granite w orkers in M assachusetts silicosis ahmc was present in alHuit 15 per cent ami silicosis complicated with ttilicrcHlosis in aliuo>t S per cent. T uberculosis was the tattsc ol death in over one-third ot the gr.m iic w orkers which is ioiir tim es the incidence lor males of 20 years and over iu tins country, lit loundrv n u n studied in M assachusetts. silicosis was less frequent (alm iii | k.t cent I and le>s advanced in degree than in granite workers. T he Inration of exposure in fomulrv workers with pnciiiiMmocomo.sis has averaged m any m ore v rars Ilian th at n ip u re d to produce silicosis in an industry such as gold mining. T he tuU reulosis hazard m ioundrus is nearly as great as that reported fo r some of the other lusty trades, but the figure arc much tower than those of m iners 01 cold, silver. eop|M-r and lead, among whom the m ortality from tuberculosis is 8 to 18 tim es the general expectancy. Death rates for all non-lulicrculous infections have been rcporlc! higher among workers in siliceous dusts than in the general population. It is suggested that the worker in silica succumbs more often to acute pulmonary infections rather than surviving the chronic fiLiuw f V 128 Tw enty-fourth Annual Safety i'ant/ress-- National Safety Connfit Silicosis is defined as a pathologic condition of (lie ItuiKs tine to the inhalation o f silica, w hetlw r free o r comhiitcd in such a state as to U* ra|iah le of setting up its characteristic patlmgcnic effects. T he principal factors that determine iltc inridcucc o f silicosis a rc f l ) flic jtercentagc o f free silica in the iiiitah-d diri; ( 2 ) iltc con cen tratio n o f silica tu rtic le s (css titan 10 tnicra in (iameter m tltc atm osphere; 13) the duration of exposure to the dust, and (4 ) tltc susceptibility of tltc individual exposed a s nuHlilieil l*y age. ctNiiplicaiing infetiinnv etc. Tin* occu|ialioital disease resu ltin g from such inlialatiou lias been M ined as **inorhid restdtN of 4<cupatiuiai activ ity traccah lc to specific causes o r labor cnitditutm and followed hy m ore o r less extended incaiucity (or work.*' M etabolism o f Silica. Significant antounts of silica arc present in all body tissues a n d fluids. I t en ters tltc hody through Iltc d iiso tiv c tract and the lungs. M ost o f th at en terin g tltc stom ach is elim inated in the *t<mls, hut a lairly large am ount i absorbed into die Mood as shown hy die constant excretion of silica in tltc urine. A ll vegetable fo u ls contain silicon c*|HTally th e hu lls oj grains, hay and straw . T h e low silica contcut of the liver, spleen and kidneys indicates die little retention of the ahsorltcd silica in tltc body. Silica content of tltc urine oi animals m ay la* influence! a t will by diet. T h e Ixxly | niscxscs a very efficient mechanism for tltc disposal o f silica because of the Imv kidney thrcshliold. Silica entering the lungs in particuUUc form is cxpcctw atcd in p art w ith its enveloping cells, hut m ost o f it is c a rrie d in to the pulm onary lyntpli channels. Matty such particles reach die lyntpli nodes am i even the spleen bv way of the blood. Tltc finest particles how ever, m ay be dissolved in alkaline hotly fluids ami carried away in solution, to lie excrete! in the urine. T lte rr m ay l*e a constant drainage of silica from the lung thro u g h the inhalation of extrem ely tine particles of silica in dusty atmospheres, so sm all th a t they a re not seen under the micrnscnitc. A ttem p ts to influence th e absorption o f silica from the lim es by adm inisiratioii of alk ali h av e W en iitcmirltisivc. Kliiuinaiion of lira I*y way of the pimmi from patients Ita tiu g <k-|*osits o f silica in ilieir inngs appears to lie higher than those Ilaving uo h isto ry o f expo-nice In dust. Only small am ounts of silica are in the IiImm| a n d th is level is little d iftrrc n i in n o rm a l' than in -dicoijes. t'altiotoay. T h is liseax* is essentially a fibrosis of the lungs developing especially in such iiulustries as liard-m ck metal mining, g ran ite a n tin g . inetul grinding ami saml-ldastiug. T he palltological changes are M icved to result from two causes, a blocking of tltc lung lymphatics hv mononuclear cells laden with dtM in addition to tltc action of colloidal silica, the exact nature of which is in doubt. T he small particles u m k r 10 m icra arc the only ones caiahh? of penetrating tltc lung tissue. A lthough silica plays th e ilom inaut role in tin- production of sdicods. th e a d m ix tu re o f o tiicr lusts tends to m odify the pathological cltaugcs in the lungs s< th a t these resem ble th en those of m iter form s of dn-t inhalation, and dw mMliiiealion (cars some relatio n to tin* |tcrecntage of free silica in the m ixture. Silicates, as in asitestos. produce a defmile cliange in the lung, as well as other dints such as m arble, coal. etc. Such cltaugcs a rc reprex-uted bv a fibrosis bruuglit aUiut Itcrau relatively insoluble niiuute particles of m inerals in sufficient concentration have been brought by the activity of phagocytic cells into intimate contact with the ptilnm nary roim cctivc tissue. T h is fibrosis is a diffuse cellular one th at occurs in the w alls of tlic sm aller bronchi and of all their finer divisions and extends to involve th e sup p o rtin g connective tissue of the adjacent Mood vessels and to some ex ten t a lso th e w alls of ad jacent a ir spaces. How ever, wlu-n the g reat m ajority of the iultalcd particles are composed of o r contain silica, there develops, in addition, a specific a n d localized ty|c of fibrosis called the silicotic nodule--an orderly w horird arrangem ent of cells and fibres, and with harp definition b um the adjacent paren chym a. M any dusts create a generalized fibrosis but only one, nanu-lv o ik * Combined w ith silicon dioxide produce tltc siwcial fibrosis of silicosis. ijencitc. known as white mica, which is a hydrated silicate of aluminum and potassium, lias not produced in anim al experim ents the silicotic tmdule. hut instead generalized fibrosis resulted. D usts m ust be differentiated into those which are chemically active and those which a re inert w hen inhaled into tltc respiratory tract. Silica is a chemically active dust which m ust necessarily be olmlic to a d v ^ rw .. tin b.i, fluid uod it> activity depends on its solubility. T his activity which is manifested in the areas where dust particles a re carried along the lymph stream by phagocytes, causes lesions of two thatJuiliomU DLuuisvs types, "toxic." ami l*oth of whirl) Itave been rep ro d u c 'd vx|icruncnt.illv. Toxic lesions depend upon local necrosis am i slow death aiul appear to favor the g ro w th of iiiImti'Ic b acilli; the sclerotic lesions produce the itodtilar fibrosis. T he inert Justs are insohthle in laxly tlnids and cannot exert chemical action in the him: tissue, hut it they accum ulate to a m arked ex te n t tlK'ir ctfcct is m echanical which may lead to a certain amount of diffuse lihrosis around the dust deposits. Certain dusts. such as carls.n, may have physical elicits, they may adsorb toxic substances and it has Im-cii suggested that on this basis there is a relatively low er incidence ot active riinical UiIhtciiIosi.s in .silieo-anthracotics th an in silicotic hines. O th e r dusts may even protect, as in the ease ot certain clays, gypsum an<l alum inum oxide. P ure piicumoitocoiiiosis m ay lie only a lalioralnry disease, a s the pulmonary lihrosis of workers in dusty trades probably results from the combined action of dust aud infection, whether it be tuberculous or not. In silicosis it is not the m ineral particles licit a rc breathed in d uring life th at reco rd the cause ot disease, but the particles th at have Ihtii dissolved. I\i'k to w ork. vtVuivncy and health may l*e greatly accentuated thro u g h the uilialatuiii of tiuely divided particles even of a chemically inactive dust when there has occurred a lymph stasis which is known to follow exposure to silica. T h is lymphatic blockage leads to retention and ucciiiiuilatiou of tlic inert dust. In Mitt coal m iners who get what is called "m iner's asthm a" we have this accumulation oi r.irlxm. Such patients are very liable to have a high incidence of bronchitis w ith mechanical ami physical changes due to retention of authracolic dust. F u rth erm o re. iini-ipii\<<al caseo f silicosis, with or without inl*TCitlsix. can no haigcr In* doubled /'tdviYuhvfif. Most apical tnliercnlosis is aci|iiired ticiorc the age oi .*3 and < silicosis at the age oi JO makes a previous tuberculosis m ore serious. .Most w orkers with lul>crculosis going into the mines before the age 1 JO die o f tulicrciilosis by the age of da. T he silicotic develops a sputum that contains tulx-rclc bacilli late iu life and the childi'm who are contacts with luln'm il.ir silicolus J c i'lo p u r y little clinical tulx-milosis. It is ini|Mosili|e to say dctuiiicly th at ul** ri u l..-i' en g ra ils itself ii| miii the silicotic o r vice versa, for we see apical tnlH-rrulosis in silicosis th at spreads .downward, while o ther silicotics show only the imIn rculosis in die low er 1'Im It lias Ih-cii louml that m ost silicotics die <>i tuU-rculosvs. 'I'Im* diagnosis of silicosis is made prim arily mi tw o litulings. the pro|H.*r history of occupational e\|H>surc to siliceous lust aud the presence of abnorm al shadow s on the pulmonary X-ray. T he physical examination and the patient's symptoms arc o f less value. There arc other diagnostic aid s such as the limlinu < large joaiititiof silica particles iu the sputum, iptautitativc determinations of silica in urine, aud a t post m ortem, chemical analyses of the lung ash supplem ented by jx'trogrnphi: esam ioaliou, roentgen-ray sjHrtruiii analysis and siwcial incinerating studies oi lung tissue. W e must at limes rely on the pathologist to determine the amount amt distribution oi lihrosis due to silica and irom microscopic studies give an opmi..n on the importance of this lihrosis as the ultimate cause of disease and death. l.u ug lihrosis may lie present w ithout any silica. Silica m ay be present in lung tissue o r the pulmonary lymph channels w ithout associated lihrosis. l-'uieh divided siliceous particles Iroin lung tissue may contain innocuous silicate which nm im l hr distinguished from harinfiil silica particles. Ilv d ra lc d sdt'M which not <|.itiblv retractive cannot lie dem onstrated with prisms. T h erefo re in the pathological section the presence of siliceous lihrosis can lie susjiected hut cannot W specifically identified with the siliceous m aterial that it may contain. Accordingly the uiH-roinciucratioii method of Irw in with hydrochloric acid is now included in the microscopic examination of any lung as a means tow ard a surer diagnosis. Ihagitosiic dillicullics in clinical medicine may Ik? more obvious if we examine first the occupational history, tjuarix grinders working under condition of massivc c\| -su rc may develop silicosis in acute form even in a period of months. whereas in other occupations it may take J5 years. W orkers in the same industry, indeed in the same room, experience different degrees of exposure dependent perhaps the dust-filtering capacity of the nose and functional condition uj the lung as deter m ined by constitutional characteristics ami antecedent disease. T he size and col loidal structure of ihc particles of silica, as well as the dosage and total amount of silica, will iiilhicocc the rale ot development of the disease. Apparently particles tliat a re larger than 10 m icra a re not pliagocytnsed in the lung. So a definite 130 Twenty-fourth Aunual Safety C om jress--National S a f\tv ('until history of exposure m ust )>c ciU bli-Jicd ami ill general hospitals w here patients are m o rato ry , comlitions under which they worked are very vaguely dvscrilw i ami tlurrc a rc not available d a ta on d u st counts aiul silica concentration. -o th at the history is often mislcadingA s to symptoms, patients can perform strenuous l.tUir de-pile extensive disease and the sym ptom s o f dys|nca am i cough a rc enuunou to many diseases. I;c u t is absent unless infection occurs, but most important is the great disproportion U tw i en a patient's com plaints a n d w h at is sect) on the X -ray. the latter showing extensive abnorm al shalows in com parison w ith th e symptoms. O n physical ex am in atio n . extensive disease may In* present ami few* ahnorm ni ] physical signs. T h e physical signs a re m erely liaise oi a general pulmonary fibrosis with emphysema, such as restriction of costal and dis|>hraeialic movement, diminu- I tion of o r intem ifud breath sounds ami a hyperresimant note. Kales are usually absent unless infection is present. A s to site X -r a y . iltcrc a re 3 essential types of -liadows dc-cnln-d. linear 'i n i x h . small discrete shadows, ami homogeneous shadows of varying sizes: these eorres|mnm! to th e librous strands, silicotic nodules, ami the conglom erate mas-e* oi tihrosis. T h e nodular shadows arc usually characteristically around the liilum, o r conglom erate n o d u lar diadnw * of hat-w ing apiw arancc exten d into IniiIi up|>er tu n c fields, o r n o d u lar shadow* m ay l>c distributed in die up|ier lwo-third> uf die lung fields, perlvaps m ore prom m uced <>n tin* rig h t side, w ith tin- tow er th ird kept rlear hv emphysema. W ith infecitou present, the shadows are less sharp or die linear stran d s interconnect o r fuse. I^irue conglom erate sliad o u s ap|H.-anuc <*t from the hiliim leav in c tlie |H*ripherv of the him; e lear thronglm iil liecause of emphysema. T h e distrihutiiHi of som e ui these lesions may Ik* deien u iu ed hy the |Nstnre assum ed hy th e w o rk ers, ami infection may likcwi-c determ ine an ultim ate atypical distribution. M any v ariatio n s from these i*aiierMs a re seen in tin* X -ray. especially under excessive c\i*o-urv or when aher dusts an- inhaled, o r in the prrsence <*f infection, ft is probable d iat die m am so im e >i the diagnostic dillicullirs is caused hy die em physem a which ninnies die physual -tens and is v>poiiivilli emphysem a, such as restrictio n of costal ami diaphragm atic movement, dtmimisihic in great part for the absence of symptoms. It mav Idol out. even on X-ray. the silicotic lesions of fine size. Kxamplcs of such difficulties in diagnosis as encoun tered hy us a re the follow ing: 4 I 'imc / -- M r. T . A forty-live t e a r old man entered the \Y w Y ork li>.-pit.il complaining oi mild cough ami expectoration of tour months' duration. H e ap|*-arrd acutely ill. his lever w as (Oil degrees am i respiration JS. Kales w ere elicited over the Upper half of ImiIIi Aides m the chest. E sautiuutioii o f fits eye ground* revealed bilateral retin al tu lic rc lcs: b is sputum contained iumier>>ti- a*, id-iast organism s. T he X -ray revealed fine m ottled shallow* distributed throughout Im Ii lung fields and a small cavity at die left apex. A diagiio-is of miliary intierculosis was made. H ow ever, a fte r one weeks' slay in the hospital, h is temiH-ratnre and puls- returned to norm al and d u rin g th e following m onth he gained IS |w>iind'. The signs m his chest now* K*came confined to die left u|H*x. In view of ins unusual progress the diagnosis if mill try tul>crculo*i* w as doubted. Ili< occupational hi>lvry revealed that up until thre years Indore entrance die Ici-pit.>] Ik- bad w orked for i d years |Mi|isIiiug leath er <>u a sandjmiier vvlicci. l-brie w ere num erous machines in die w*ork room and n o precautim is w ere observed to elear the very dusty air. H is sputum was ex am ined th ro u g h die kindness of |) r , Ihirke of Kavhrook. X. Y. who lutiiitl it latleu w ith uum crous doubly reiractile silica particles. IK- expressed die opinion th at this w as consistent w ith silicosis for he hail found such num erous particles only in cases of silicosis. T he patient subsequently divd oi a luln'm ilm ts im'iiingitis. Retinal tulierclcs w ere dem oustrateil on microscopic section. The pathologist* rcjKtrt w as m iliary tuberculosis. Ashing of the lung showed increased silica content. consistent w ith undue ex p o su re to du>t (m ore than 1 mgm. silica per gram dried tissue). | ' ' j| . ; C ost I I --M r. R ., ag ed 54, en tered the New Y ork hospital complaining of hem optysrs. dys|Hiea and chest pain. O n physical exam ination there w ere rales and dullness over the upucr third of the right chest anteriorly, l ie ran a low grade fever but w as robust and felt quite well. T he chest X -ray disclosed enlarged hilum shadows, particularly on the right, and diffuse mottled discrete shadows ` * :*` IT*. V*.. - . '..I \!*~ t ' O ,*uRational f)i.u'tiscs Ul throughout both lung fields with a trircumscrilied density m ar the right apex. If gave a histo ry of lu v in g w orked for tw enty-four years as a c u lle r ami sizer *i aslM-Ni>N-i<rtiuiiiitm jkijkt box hoards. T lie room s w ere in a continuous cloud of dust. F.xainm aiiuii ol tlie dust revealed S |>cr cent silica content. T lic hemoptysis, w e tell, w as to lc explained on the taisis ot infection o r neoplasm, hut u c did uni know w hether we were dealing w ith out* of tliose processes alone o r a n asvtcialcd silicosis o r asliesto>is. A small nodule in tlic neck was snhscipKiitlv rem oved aiul show ed carcinom a. VVe a re inclined to believe th at this dk-s not explaui the whole process, as the m an is still alive and certainly, from tin* X -ray standpoint, we cannot say th a t th ere is no silicosis. tiJ je H i -- M r. C. A dish-w asher, act'd 4fi. cutered lUllcvue Ivospitat Ihcausc of cough and expectoration. associated with dyspnea. There was some dullness and rales at the right base p o s te rity . Chest X-ray revealed a homogeneous shadow at tlic right Itasc. I lis sputum contained no tubercle Isacilli and lipiodol study revealed no abnorm alities. Hrnnclioscopic exam ination disclosed a bleeding m ass in right m ain bronchus. Sym ptom s a n d disease progressed d u rin g tlv.v iotlow m g to u r years. IW r i te mottled shatlows first ap|tcarcil in tlic upixf right lung held ami the -hadow- a t the rig h t base cleared somewhat. T h re e years late r extensive a b norm al sliadows w ere present througlioiit bolIT lung fields, particularly <m the rig h t. D iagnosis nl elirnic jiennmouia ot unknown etiology was made. A t no tim e was a diagnosis of silicosis entertained, because as far as could lie determ ined he had no histo ry of ex|wsiire. F urtherm ore if th ere were silicosis it M ia ie d w r y alypivally having the lesion rollfined practically to the rig h t base at the iM-gjmmig a nd then spreading to iltc leit lung. A utopsy however, revealed a typical -de< associated w ith a small legree ot tuliereulosis. A picture of the lung showed how much m ore extensive the silicotic process w as in the right lung, 'th e re was stenosis of the right m iddle bbc bronchus with hroiicltiectasis in th is lobe. t hroiue inierliott in the lung field probably accounted fur the unusual lM'ali/.llill. T in case illtt-trates how* necessary it is to have the history o( dust c\t*o>nrv h .r w ithout it here we are unable to even suggest a diagnosis. Cure I f -- Mr. t \ , aged 45. complained of rough and dyspnea w ith slight expec to ra tio n ami gave a history ni having w orked fur m any years repairing tir-s. using tale powder. It was diilieult to obtain accurate details as to the possibility oi silica exp<siirc except that the rooms w ere tilled w ith clouds of hist. Kales w ere present at both apices and a lew tubercle Jxicilli were found in the -putmii. Discrete ami stringy shadows were disseminated throughout both hm g field-. W e know iroiu the |>ositive spuiuin that tuiierciilosis is present. T h e patient lias, how ever, tieeu well lo r a period of tw o years. Tlie doubtful history of c\|M<-ure together with the numerous discrete nodular shadows in his lung, which are eonsistent with silicosis, makes this patient a problem. Is this tuliereulosis alone or is this tuliereulosis w ith silicosis? T h e patient i> still Ih in g a w a r biter and working. C.Htclusion C'ases such as these arc exceptional, but their existence m ust alw ays lie Ih.rnc in uiiud. If occupational history is >nadvpiate and \ - r . n . Ih u ral and iaitoratory studies prove misleading, the diagnosis may pre-cut great diihcnlty. H ow ever, a comprehensive study ol all jmssible data usually clears up the problem with reasonable certainty. .WJOUNNMHST