Document ZJ2x5Nzg2MBZO61NEz0Gbm0M7

FILE NAME: ZD^D/ DATE: DOC#: ^D/ DOCUMENT DESCRIPTION::ZZZWZZZ ,.J 1! ,''. ' I I " ~ ~ y ~' , , l ': "\. ' j I , ' ::1 ,\ ~ ,_,'.' pq :. ; i . ''\ ' ( ... "~ I ~ : I(ii'' ~'-1 ; 'f', ' .,~'\ ' t .. +" ()tl(JJ\I ~, f1 ! A REVIEW OF PNEU~IOCONIOSJS FURTHER ROENTGE~OLOGICAL A~D P.\TlfOLOGIC.\L STLDIF:-i* By HENRY K. PAl\COAST, .'\l.D., 1111d H'C;J'\L P. l'F'\lll.Rc;R \<,S, !\f.D. ca '' ewitl ar JN l'HIL\IJl:l,l'HI,\, P~.:'-IN'>\ !.\"\'II I a~ 1925, at the request of the Editor of quate ovcr,,ight, hut largelr because of ti~ P.< the .1111crica11 Journal of Rot'lltgc110!0.o geographical extent of this c()untry and tlie Sl and Radium Therapy, we reviewed the ~cattering of the more or Jc,,s danger<:l1' roentgenological and pathological aspects dusty industries, there is a lack of knu1-1 l- of pneumoconiosis in a paper presented edge of that prevalence and its seriousncs~. before the American Roentgen Ray Society :\s the rocntgcnological examination is and published in the Journal" 0 of that year. the most accura-tc anc( satisfactory method A more complete presentation of the sub- of detecting the condition from its earliest ject was made in a monograph" 1 published to its most advanced stages and of stud~ in 1926. The condition has aroused a sur- ing its ilrogres<.; and it~ incapacitating ef- prising amount of interest throughout the fects, it behooves us as roentgennlogists to civilized world in the short time that has he familiar with all of the phases of the elapsed since then, and especially in .i1is disease, and not solely \l'ith the rocntgcno- country. Papers have appeared in great graphic appearances with which all of us numbers, further npcrimental work has arc more or less Familiar. \\'e mu'it play a been done and numerous investigations large part in the cJucation and the public- have been carried out, especially here, b) ity which arc so much needed to overcome federal and state health bodies in connec- the ignorance still exi>.ting, even on the part tion with many industries. For these rea- of employers and empJu,ecs. \Ve will be sons it has seemed pertinent to present a called upon for our part in the program further and up-to-date review of the sub- leading t'l the enactment of satisfactory ject to the body of roentgenologists. co111pc~1sation la\\ s which are sure to follow This increasing interest in the subject is a in time. In the meanwhile, civil suits are recognition of the great importance of the increasing in number and we must train condition of pneumoconiosis as a more or ourselvcs~in order that we may be able to less necessary risk of commercial develop- testify, when called upon, h~nestly and ment in the progress of civilization during iustlv for the benefit of all concerned. recent years. This has led to the enactment . It 'has been our endeavor in this pre.;cn- of adequate compensation laws and regula- tation to avoid as far as possible any repe- tions governing the adoption of safety titions from our previom publications, :ind measures intended to eradicate or modify references to them will be made only \1 'en the essential dangers of occupations by it may he necessary to better expl~i11 he many countries, notably the South African newer phases of the subject. Union, Australia, New Zealand, Cheat Britain, Germany and one of the Canadian NO~! ENC LATU RE Provinces. In this country we have no federal laws directly applicable to the enforcement of controlling measures or compensation. In only a few states is pneumoconiosis a compensable disease. Some states enforce regulations directed toward protection of workers. It is a con di ti on which is all too prevalent in America without ade- \\'hilc it still seems probable that .. ;J1c:1 (SiOJ is usually the active fibrosing ,1~c11t in the condition which we recogni :ts essentiall~ a pulmonary fibrosis, .1:lh'. 1 ': 11cc to the general term of pncumocnnw~1' 1 sttJ seems advisable just as much now as at the time of our pre~ious presentations cJ the subject. Some other dusts undou litecll~ From the RadlologicJI Clinic, University of l'cnn,ylv.inia l\1ui1C.d Sd10ol and flosp1t.d, !'l11l.1dclph1.1, l'.1. Head .it 111 " I hirt)' lirst An11ual l\!eeting, American Roentgen RJy So('lety, \\ c>t Badt11, Incl., ~cpt. 13-2(., 19p. , <1',, 5.'/> . ' , ,\' ' . d ., .. : !t"' '' .L I , : !~ ' > 586 Henry K. Pancoast and Eugene P. Penclergra~s ( )( lflll I R, 1'i 1 bestosis is ample reason for the presen tain- over vibrating machines. The heavier rJ,~: particles are separated hy gravity and ii.~ tio11 of a general resume of the entire dustry, as well as the pathological, clinical asbestos fibers are aspirated out by vacu~ .1 and roentgenological aspects of the condi- fans into special chambers. The crude bestos is then shipped to the various f ; _ tion . The dust evolved at the asbestos mines tories. All of these procedures are carri :rl contains a moderate amount of silica. The out at the mine bases because of the ecr>'l- harmful products of the asbestos factories omy in shipment of the lesser bulk of t be are almost entirely silicates. Heffernan42 belie'V"es that silicates such as asbestos undei:- crude asbestos. The mining part of the industry is at- go changes in the lungs quite like silica, is a true tended by the elimination of a large qua11tity of dust, which contains silica as well as only slower, and that asbestosis silicosis. This is, of course, not proved. silicates. Pneumoconiosis is found among The product was mined and the asbestos fibers were separated from the mineral and tructablc the workers. Very Ii ttle has been written about the conditi~n of these men. Recently we have had the opportunity of examining employed in the making of indes fabrics several centuries B.c. Attention is the roentgenograms of 58 men from one of called by Cooke17 to a cremation cloth deterials the Canadian mines, some of which showed pneumoconiosis. As the mineral rock con- scribed by Herodotus 450 B.c. Ma made of it have been used ever since then, tains as high as 60 per cent silica, the mine but the most rapid development of the worker's condition is due largely to this commercial industry has been during the directly, although probably not entirely. The raw product which goes to the factories past two or three decades. Nature. Asbestos is a peculiar fibrous and contains very little free silica. crystalline mineral composed almost endrate mag- The most dusty occupations in the industry are to be found in the factories, in tirely of silicates, mainly of hy nesium silicate, with varying admixtures of which the work is done in inclosures where those of aluminum and iron. The general silicate minerals the asbestos is refined and is finalh spun and woven into the various materiais with term is applied to all which have a fine fibrous structure that can which we are familiar. During all of the be split up into long, flexible fibers for the factory processes, a large quantity of tine dust is set free, but in var~ing amounts in purposes of spinning and weaving. The fibers will split up in a longitudinal direc- the different ones. \\lost factorits, at k.1st tion almost indefinitely. The minerals differ in Great Britain, have devices fur re111< 11i11g in their exact constituency, especially as the amount of iron and aluminum, in much of the dust. P;ar~v Casr Repo1/.1. The tirst report ,,fa to different countries in which they are found death resulting from asbt~tm. dust i1,!1a\a- and mined. Much of the asbestos used in tion was presented hy \\lurray /" in ,'ioa. The man worked in a facton for ten n::rs, Great Britain and the United States is mined in Canada. Cooke17 gives the follow- mostlv as a carder, and w;{s the ~(,k .ur- ing chemical composition of asbestos: vivor: before his de.1th, of lo other llH ,1 1' ho started work with him. The auto!''" on per cent this case revealed pulmonar: fi\ 11.sis. Silica. 40,87 Photomicrographs of sections of the Ii, igs l\fagnesia .. Iron oxide. 41. 50 ';), RI showed large spicules of asbestos, at least Aluminum. 0.70 th~y were so regarded at that ti~11c. , I \'\'ater ..... !J 55 fhe second case reported 111 1rn:d1c.a The Industry. At the mines, the mineral is n ma- literature was presented by Cooke, 16 111 1924. It was again reported by him in d7- blasted, crushed and finely ground i chines. The crushed <lust is then passed tail in 1927.17 This individual stopped his ,t J.~mna~E~=~~Y~Eam~~~~L~~~~~~~~~~~ 1 ~~.~ ~t,~~t.,~:.~ 1>r"";t _l' .'~A~~~t\.J.. ,1 ~;~ ~_,. ~... illilllii.llilllillia.niiillWIW!'.!i:,..;o.>.,.,, ' -.r ~,_. . , ,_, \'oL. }. X \'1, N11. 4 Review of Pncumoconiosis work in a hctory after eighteen years of slight fibrosis in addition to the evidences of the tu hcrculosis. The second case worked intcrniittent occupation. The cause of icat'i \\as probably asbestosis and super- two years in the mill and died. Thiethpfhibyrsoi-- ;1npp<cd tu berc:1losis. vV~ re~erred. to this cal signs suggested tubcrculMis w sis. Autopsy showed n moderate degree of c: ,, i11 our previous contnbut10n,91 1n 1926, 1 :is J,: 12dy a tuberculous one, especially as i~ 11., 1: the first available autopsy report in fibrosis with nodules, hut quite cellular, , and not like the usual silicotic nodulei;; There was no evidence of tuberculosis. The the !itcrature. In view of the many deaths w\,j,h have been reported since then, we various asbestos bodies were found in both first, be- niu< now concede that this cleat~. was cases. These cases are of interest cause both presented definite evidences of pn1ii,1lily the result of both cond1 t1ons. Nat1-rally, Cooke was the first to describe asbestosis after one and two years' work dies .J thL' HtlllSUal and characteristic asbestos respectively, and also the various bo characteristic of the disease, and, secondly, hod:,-; in the lungs, and the authoritative dc,ci 1ptio11 of them was made in his second for the reason that the second case pre- rep(lrt of this case in I 927. These bodies will sented the terminal symptoms and died of the condition after only two years' occupa- be described in detail later on. The second paper and third public re- rcscn ted by Oliver, 87 in l 927. He tion. Wood and Page,130 in 1929, reported port was p reported the cases of two women who had died as a result of asbestosis after working years respectively. autopsy findings in the case of a woman who died of bronchopneumonia after nihe years' work in a factory. There were no thirtv and eighteen \1"either individual had evidence of tuber- evidences of tuberculosis. The lungs showed diffuse fibrosis and thickened pleura. Nu- culosis. l tis interesting to note that the second of these cases stopped work after merous asbestos bodies were found in the eighteen years' occupation, and did not de- lungs, but not elsewhere in the body". Wood and Gloyne,129 in 1930, reported the autop- velop definite symptoms until four years sied cases up to four. Tuberculosis was later. The next report was by McDonald,68 in found in three of these cases, and in two, bacilli had been found in the sputum before 1927. He referred more fully to Cooke's case, and reported an additional one which death. Haddow,36 in 1929, reported on the died. He thought it reasonable to believe that in the former one the tuberculosis was is own case did deaths of Oliver's two cases, and on two others. He stated that the certificate of the last one, March, 1928, brought about the a superadded infection. H not have tuberculosis. In addition to the two t\pes of asbestos bodies first described a third, all three of publicity and official recognition of the condition. Since then, the workmen's compensation act of Great Britain has been ex- \JI Corike, he added which are now recognized. tended to include asbestosis.n Haddow case states that one of Oliver's patients had :iciler,101 in 19:::8, reported another ho had workeel twenty-two years in vari- tubercle bacilli in the sputum. 11 m10 capacities in asbestos factories, and prl' _, 1,d tht: typical symptoms of the ad- bacilli were found Simson103 quotes Hoffman48 as reporting 13 deaths in 1918 and Collis,12 5 deaths in 1910. These were in health reports, and will v:ir I _'l~e. '.'\o tubercle Putu111. The roentgenographic ap- be referred to again under predisposition to 1'1 1.. \1l' 1 cs secmC'd not to have been unusual. deaths tuberculosis. Mereweather and Price,73 in their recent \:. at"' :1,1"1 in 1928, reported two ;11,hc;,tos mill workers in South comprehensive report on the asbestos in- .\tr!\" with autopsy findings. The first d of dustry state that approximately 2,200 individuals are exposed to practically pure man ,, 'I keel onh one vear and die miliw tuhcrcul;J;,i;,. Tiie lungs showed ashestos dust in the factories of Great ~ -~:1 f .-i ~.. t j~ 1' " - i' :~ !:._. . .,"'' I, ''J . ~J ' ~ ' . '',,, 1, ' _(. 1 \ t ~., l_j, ( n I ," , , , " t .' . '~ " ~ ' 1 '. ,. . ' 1 .. .'\ ' . " ' ' ... , '~ lJ ~{t . ~ J.. . ' '' '. ', .r ' --~- ~ .,. ' l '' ..;. ....-. _ '{'..<f~~:.1-.:.r,,~,_t.~1!1..tf:::.<~ ~1 --~ ~"' ir 1 i"it ,~.;.; t ~ f;,.i , ';T.'!.'<,".':.'.~. ,.~.J.;.'~_,lJ<il,,,.', 'c........>i- _,."T;,_..., \,_!.fl~'!\. ,,,,~ ' ' ' !~'.4 ~ :'j i'" .",. ; ,;1l~.lr.0:.l.~,:-)i'-";in.~-.'..1,n,,. ~ ~ -~ ,!)J .~A,, ~ ii!i.'t .,' ,' . f"!' ft-. ,, ~ ' !'If : "~.w j .. ' ~. ::;~ ;~ .oa J, 1' ifJ, \'J _;' l\, /:.': .J i,fl ,. nl t''T r~ ~ ~ I ' . A ,i.' ... :. . ,. -"~, l ; '.' : :1'~ii :) ~,r;;::;\ t:i'~, <_ t:~ :'.\~ fr' ' 1, ' :~;~:!1 .;~: f : r-: it : ' r '' :." r. .'; t... l i r~ S' i~~ -~ . -: '.;1 1 ~1, f' '. '. 1,: l " ' .'" t , r-'; ;, :.: r .Y '. .,~f ;.~,.':I 1 ~ ' ~' ~ : :, '>.!r -~ !'.~; 'f.' , '<: \.; -f,, f. .~-,lt' ,. ,. 1 ~ !-'h ..., ,. 1 h '. , ', ~ ,i,"~: " ~ ~ : "~ \i ,~." i . 't\ p ,f4 '.~~i J' . , q\ .f.' ';1 -' r tj J-k':..... .. ~ i '~"'.ji~ ..... , t ) -: ..,., .; ?~I \~ ;, -~ ~."'. J . ~~-,:~:_' ~.)t'.t r. 1. ,. ~ i'"' ~i fi .... '. ~~~,;;;:-~ti~ l . ". -r.~...~ .' '( l ' :, ,1; '' 3~.,'. ~!; i'.,; , , 1 t~,' 1 ::1. ' . >, . ~ . ~t: .~ .:l.-. . , l , the ~~{';, ;. . {'!-'': ...'.,'-. ' ' t:;~ 1:~.' . I ,: . :1 1~ .. . '~ ~~ ~~I ;; t.,_''> _' ' 88 Henry J(. Pancoast and Britain. These authors examined ,lh.1 individuals among the workers. Of this number, 230 had been employed less than ten years, and only 21 over twenty years. :\II but one of the 363 individuals had been working at the time of the examinations. Ninety-five, or 26.2 per cent, showed definite evidences of fibrosis, due apparently to asbestos dust solelv. Their table of the time incidence of the ~ondition is of interest: --- ------- ------ -- -- -1- -\Y~e,a~rskat_ Cases F,,1mincd __S1_h1 o1~wr-ionsigs_ f'cr Crnt -- -- - -- - ------------ Eugene P. Pendergrass ,,, '"'",,, ..1.P tercsting to compare the findings in i cse cases and those of Simson with the cl11 al table of \Icrcwether and Price. It is 1 .1te possible that protective measures pL :d an important part in the incidence :ie condition, as sh<rnn in the report <d :he last named authoro,. /lppearancc nJ //Sh!'.l"!Os IJ11st. Cooke ;,l< has described the microscopic appear:rnce ofthecomponentsofasbestosclustinsornc- what ( 1) t hSemfaol lllofwriangg~1menatns n eorf: asbestos fiber. . l The hulk of the fiber JS trans ucent and glistening, with here and there within it opaque particles and minute black gran- u les. These apnea r to he actualb . 1)arts t of the fiber, but t their appearance suggests dif- ferent chemical C0111positiOJ1 and ph~ sical ~ \ :~~ " <'~ . -~, .fl 'I,. .!.ri f' _~ :~ . .' ( J ~"I F ~.; t:~ ~ r_ ~~ t, ~~ ~.. l ~ ~.'. ~r1,~ t"'.i, .,._,~ ~~c,,1. , ,~.;i., \'... ' 1 ~ ' ' ;.. ;?' 1t , , ( .i ' . .,. characteristics. (2) Translucent spic11les split off frorn the This table does not apply to any one group of workers in the factories. The authors have collected also, outside of these statistical cases, records of 10 deaths resulting from asbestosis, 9 of which were verified by autopsy and the tenth by repeated clinical and roentgenographic examinations. Nine of these deaths occurred from 1927 to 1929. The exposure of the IO cases varied from nine to twenty-four years. At the time of this writing, Lynch and Smith67 (1930) are among the latest extensive contributors to the subject, and their report has been the first one in this country, at least in medical literature, to deal specifically with the subject. One of their cases, a ncgro, ~ied as a result of a gunshot injury after working twenty-eight months in a mill during a period of three years. His lungs showed definite interlobular, perixascular and peribronchial fibrosis, and also the various asbestos bodies. The secand case, also a negro, died of lobar pneu- mania after four and a half vears of con- frnuous work in a mill. His iungs showed everywhere a definite increase of young fibrous tissue, in addition to the various asbestos bodies. Reference will be made to other: cases examined by these authors in description of asbestos bodies. It is in- fibeis. (3) Black, brown and blue particulate matter. The black particles are iron. They are few in the finished asbestos product hut are numerous in the <lusts of the carding rooms. The iron in the finished product was f I only 0.1 per cent, whereas in the dust o t 1e carding rooms it was 18.-1- per cent. /lsbcstos Bodies. This is, perhaps, the most interesting feature of pulmonary asbesto- sis. The various bodies found in the lungs of asbestos workers have been described in detail by numerous authors, notabh by Cooke,16 l7 ,t8 l\'lcDonakl,r.x Sirnson,10' G!f,, ne,Jo l\Ierewether and Pricen and [,, nch and Srnith.r.7 The description given b.y C(l11ke15 of the various asbestos bodies is as co111NC- hensive as that of any other author antl is abstracted as follows: (1) Enormous amounts of fine gr:111ular pigment like that seen in the asbestu.; dust fiber. (2) Much J,arge of or mtohdisermata~v be size c d arhon angul an .tr \ 1115 par- ticles't ro to 3f>o rnicrons in size, corrc~i'cnd- ing to the black, brown and blue partic1~Jnte matter found in the dust. These p.1rncle5 are found in fibrous and necrotic areas, singly or in clumps. Because of their size, they might occlude small bronchi. , (J) J\lmost complete absence of the ,er) ({ 'f:.'> t,',) <~- ~: it." A,.. .~~, .v ~ : ~1\1 ;~.... 1i ~r,, -''~.~ J ~ "" .;~ ~ v ~'Pi: "' t..' ~ :~ .{ . -~. .~}... .. '~' '!i ~, :'~1~ ~- . ~ ( '") tt: , ~1 :..~. ~ J, . ._ : . ii ', '-:_" "~' ..: ,':i~ :'t: . ~ 1_, '. ' \ . , I I ' :1l !~: .7:~-~t"!'FlJ!l~"l~i1!1".~.~!l;s:'"lfAl!l!. ~1'.1.tl"!W!l'.'!l!"'!ri!lli*:l!l<'llSl91:!12~1!17l'J~.'t"'~\'il'.l~'1:~!1!1,~"l,JIP!'f.!Jlf"-~:l'.~;ll!*%tfMll~l1:l."J.~;,<1"!51!1fl~tAlll,tlfl':i(ill JI!~-:~,"Jll:;+l!.fl\l!I,.!'l.f'"'~!,!1!~'1,~J'l.~ll-!!1!1~\~l!t!lJtiftl!"':'"~"'!f"~"~'"~ll'lll~'l~ll:~l!-~t\lli~ll!f';-'i:czwtll,rll~1'":!l!:~~P'l'.'14.,fl,~_il!l!i~l'i. -~;'~~ --. ., ..,. ....., ,""'1- ( .. .-~, ,~ f ,f;~-< ,- ;.. ... :""; f. >4'., __Pllicqill. ~ '> ~ ;~ ' n~'~ ~ , '<' (1 ' . ;.,." "/..,.. ' ~ ~ ~ ,; 11' ,. ri- ' , } t :- .. ' ' ' ?l. ' ~....., ... ':,.;, 1 -- ,, '1_'-\ o;t \...,.P ,:'r";Q '!.~ ,~-:\1: . ~...!. ::- ... _ <, ..,I ' "" ; . ' 'i' ~ I \ cl -i ' I ,I iJ"1 -~ ~: ,'I " .I " ~. ' <~~ "' \! i ) .,'.i '. .,I , '' (. 592 Henry K. Pancoast and Fugcne I'. J>endel'grass f )1 JOH! ' ';l! of course, as in any fairly well a<lvanced case of pneumoconiosis. The must unusual feature of the condition seeme<l to us to be the fact that in both sets of roentgenograms the appearance seemed to begin more often on the lrft side than the right and progressed more on that side. This is the reverse of what is the rule in all other occupations we have studied. l\lerewcthcr 7~ states that it begins on the right side, as one would expect, and the cases we observed may have hccn examples of the exceptions which arc occasionally observed in cases on careful analysis re!>olves itself 'to a fine mottling and linear shadows\~! .h, toward the base, may look like cohwe'. ' It is evident that the nature of u,,_,e changes in the lungs requires the :, <;t type of rocntgcnogran1s for their pfJrtn ..ii. :'.\lso, the seriousness of what may :,eu, to be minor changes to the uninitiated requires a rocntgcnoscopic stud~ of diaphragmatic movements to make one realize the actual state of disability present. It is evident also, as i\lcrcwethcr states,'~ that an opinion as to the degree and intensity of an asbestosis ti hrosis based upon a cornpari~on of rocn tgcnogra phic changes with those ~hown in standard silicosis films will be an u ndercs ti 111 a tc. \" . " , \, ; j ', 'S~ ,,.f~~- .. ' ' "-'}," "'._. ' ~ ,1 FtG. 9. Pneumoconiosis in an asbestos worker. Male, agC'd forty-three, employed for seven teen yc.irs and a superintendent at the time of examination. There arc two prer!ominant tvpes of fibrosis in this case-pcrivascular-perihro;1chial-lymph node and fairly advanced interstitial. The latter is indicated by the general haze toward the hascs, and more on the left side. Note the partial ohliteration of the left heart border. The size of the cardiac shadow is due to the old technique of many years 'nagnory. Dreisappihrartaigomn, aenxdcu1rsjioinnch~ oinncfhorecaedchressidpeir,aotirodni-. any industrial pneumoconiosi~. We noted the same tendency to obliteration of the left cardiac border as mentioned by Wood, because of the diffuse fibrosis and the prominent trunk shadows. Wood states that the late stage may or may not show consolidations. \\'ood and Gloync 10 ~ state that the ground glass appearance in late Of the 363 cases examined by i\Iere- wether and Price, rJ.5 had rocn tgcno- graphic studies. Of these, 52 were said to have presented appearances of diffuse fibrosis and 22 were suspicious. We have had the opportunity recently of examining in consultation the rocntgeno- grams of 58 men employed at rhe mines in many occupations an<l during periods v;iry- ing from eight months to forty years. Of this number, T5 showed clefioite evidence of pneumoconiosis, one was doubtful and 42 showed no lung changes. The longest worker showed a moderate noduhr stage of the condition. The shortest tirnt'~ in which definite changes were indicated \\ere four years for one first stage cast, five years for another and five years f"' nnc early second or nodular stage c;i~c. i'he worst case showed a diffuse third ' tt'.e fibrosis after thirtv-onc vears' occup:.1 11111 Asbestos mine dust i~ not comp:u .tlilc to that of the factories for mam fl'' 111 1:,. Some silica is present, hut there .is 11"' '.he great concentration pf asbestos dust;, ,he mineascompared to the factor~-. h:: .,,u~ own experience so far, we would not 1t.:in the hazard at ])ro-.;11o.r1s. the 1 t 111i nc as vcn grc:1 seems to 1uc I t ,... thcr genera'I op1.n1'011 t Ii a t t I1c t ll' prngnost'~ " 1'I 111'-. monan a~bcstos1.s anion~ f-actory wo 11L' r rs is to b~ regarded as grave protcctt.on~, 1.11 a ,-argc ""ithout 1111111 IJcr ackqu:itc ( (''!Sl'S ti ' ~ ~ . f' . .I ., '-' ..;, ' . (',- .' , :j !;.< ,' . ,. " . , '.',:i ,~. .,- h .'~ .~ . r 'i 'I ., ti 411UE I ZWSl ll\f4Q fF 4{1 @_I +)iPIFi _MWl414~%PAtOJA (! '.Q@ ;;;g:u f;A..-0 ~i <fAP q;LZ&A a. " /dil!'k !~ 1" ... . ~ <t . 1 t,,. 4. ,. '. \'nL \ \ \ l . > I Review uf Pneumoconiosis 593 anw:1g; tho'ic wlw work where there is great ccnice11 tr,lt ion of dust. The con di ti on is :ipparc11tl\ proy;rcssivc even after cessation of olCCllpation. \lercwcther and Price state th.tt 11 ith continued exposure to high conccH1 :itiun dust tlbro~is may be fully dcidr,:1,d in from seven to nine years and t1nl1 rna~ result in about thirteen years. \ \ 1t ', i''iS concentration, fibrosis may not be full .kvclnped for fifteen, twenty or t\\< i'-tivc years. Inhalation of dust in hil:!' c(lncentration results in a more 111 ,. ",d dcg:rec of fibrosis in a shorter time thn ''hen the concentration is lower.. , 1i.cp11sitio11 to '/'1ib1Tmlosis. The condit" ,., (lf pulmonary asbestosis being a new chi1.1 111 th<~ pneumoconiosis family, a great aii1 <tlllt o( interest centers around the incidc11cc of tuberculosis. :\mong the early cao,c reports referred to in the beginning of this occupational section, pulmonary tu bcrcu losis was reported as an accomp:rn; ing conditio11 in a few instances. Cooke's c.tse had advanced tuberculosis. Simson reported one case which died with tuberculosis and one without evidences of the infection, He thought that we could not as \ct formulate any definite opinion as to the frequency or the predisposition. Simson quoted Hotfman 4' as reporting IJ deaths among asbestos workers, 3 of whom had tuberculosis. He also quoted Collis 12 a<; reporting 5 deaths from tuberculosis among less than 40 workers at a factory. Wood and Gloyne 12 '1 referred to 3 cases showing evidences of tuberculosis at autopoy. l-foddow10 observed many asbestosis cases and among them 4 died. He did not believe that the condition predisposed to the infccton, at least not as a rule. l\lerewethcr a11ci Pricl' <;tatcd that asbestosis dill', r<; from <;i\ico'i" in the distribution of the 1il1rrH1-; th,11c, in more rapid develop- tllC' t, in rnen tgenographic features and P', : I: in a ll'nmcd rn.raptibi!i(\' to t11bero' . \lcrc1\ L'ther' states that out of "L" txarnincd, evidence of active ilr1'h wac, found in three. He thinks .Iii!', there j, IHJ outeitanding sus. '.1n pnJ\ eel, he doc'.> not agree that the question has been finally settled as yet. . Compensation Laws. I .egislatioi1 irLinany . countries and states provides for com- pensation for silicosis, which is a condition produced by silica. Asbestos is a silicate, and if ~e arc to regard asbestosis as. a silicosis, as has been suggested but not . proved,. the latter condition is only in- directly caused by the asbestos. Certainly . the legal status of asbestosis as silicosis has not been established. In some instances asbestosis has had to be made a compensa- ble disease. HA RD RocK MrnrnG. This group of workers comprises the largest engaged in any single hazardous industry through- out the world, provided the rock is of a si- liceous nature. The large amount of dust evolved in the various processes of mining is always dangerous unless adequate pro- tective measures are adopted. The driller? and those working with them or near them are prone to be the most exposed. If the fine dust is allowed to escape, it remains suspended in the air for hours. Blasting al- ways stirs it up. \Yithout protection, the usual typical symptom-complex and the roentgenographic appearances develop ear- ly and progress rapidly, and the workers are predisposed to tuberculosis. More has been written upon the hazards of this in- dustry than those of any other. Numerous writers have been extensively quoted else- where. Many more or less similar indus- tries and their hazards have been described in detail, such as the drilling in coal mines, granite cutting and sandstone quarrying. The most detailed descriptions of hard rock mining have emanated from South Africa through individuals associated in nmlical work or other ways with the lbnd gold mines. These mines are so often re- ferred to in the literature that a short ab- stract of the description of the region and of the character of the rock may be of in- terest. Cluver10 states that the first gold mining in South Africa started in the Transvaal in the 7o's, and the first gold was taken from the Witwatersrand in 1885. .,; J' ,- '' .; '.:' 1: "" ';. -'~1- ~;. ,. ~ . ,1 , I 0 ..... - i I , . ~ ~. ~ ';ll; . " ,..