Document 3JjX5LmRqEGG55L3dRBpxYJbD

r r*' u . NOTE: THIs pr NOT CCiiii. i /it, #> THE OCCURRENCE OF PULMONARY FIBROSIS AND OTHER PULMONARY AFFECTIONS IN ASBESTOS WORKERS (Concluded) E.E.A. Merewether, M.D. ', $?!*:> : H. U. Medical Inspector of Facioritt ;rjf T ,v Morbid Anatosiy . `j-l Professor M. J. Stewart of Leeds lias ^kindly supplied me with a detailed ^-description (dated March 28, 1929) of *.*;*postmortem appearances of several The totally fibrosed areas of lung show grayish-black mottling, owing to immobili sation of carbon. This tissue is excessively dense and completely airless; but there is no evidence of calcification. Other por tions of lung show varying grades of the same process, and even the least affected cases. From this account the foliow- parts are definitely tougher than normal. 'T^ning points are extracted: In none of the cases was there any evidence 1 of an active tuberculous lesion. , |.V The gross morbid anatomy of this lesion, aa seen in persons who have been at work for Histologt ' .. &'. >nany years in the dusty atmosphere of an '.'^ asbestos factory, consists in a widespread ,:t?-'-Pulm0I>ary fibrosis affecting especially the basal region of both lungs. There are ex* :V;; tensive, densely fibrous adhesions througb. . Wjr-'out tbe pleural sacs, which may, indeed, be* ^come completely obliterated. In particular, the bases of tbe lungs are firmly adherent to Jr:, the diaphragm, and between these two "r structures there ie often a thick, homo* The essential lesion is a chronic interstitial fibrosis of the lung. In. the earlier stages, there is fibroblastic proliferation in the alveolar walls, which become increasingly thickened in consequence; and there is catarrhal desquamation of the alveolar epithe lium. At thisstageofthediseasepeculiar golden-yellow "asbestosis bodies"' are found in varying, usually con Ves~.--pulmonary fibroeia and pleural aae ^obliteration--bronchiectasis develops in O&fjthe midst of the more grossly diseased tissue .v?i|4n<* go on to the formation of multiple ^'Abeeeaaes with smooth walls. .^fl':-."The distribution of the fibrosis, apart from tb extensive basal lesions, is rather -`.^.irregular, the peripheral, eubpleurml regions ^ of the lungs being more affected than the * central areas. In one case in which the pa- 'Xy tient had lrcn away from work for four years (following nineteen years in the mill), the areas of dense fibrosis were extraordinarily sharply circumscribed. Tbe nodular char- "^,-actcr of the* lesion which is so striking a " ' feature of silicoais in its earlier atages is not *' met with in thia dimu siderable numbers, both in tbe alveolar spaces and in the thickness of their walls. Detached portions of bodies may often be seen engulfed by alveolar phagocytes, or a large unbroken body may be partially surrounded by these cells. In tbe more advanced stages of the disease, the fibrosis of the lung is complete. Alveoli can no longer be made out; but the asbestosis bodies still remain embedded in the fibrous tissue. Varying quantities of carbon are also present, eluefly in little masses as though it had been contained with in phagocytes. Chronic bronchitic .VijrVrf. ]) 3KHe. 239 f ft * . /f *_ w TLES-i&m ' :-3gsi w rM m >.s' i3 .l` .'''.v! V'j : ' . /' * .*. .' >vA tl . \ i .. 1 , - *;** ,A1 . * I- , . / * . . v hvwwswfei i-tftfirsts I '4** i ' i ' Vatg 000 713S""fSSJ? IV* r 1 .v.A,--. ] 15144 fetifchiV vl-J dt*lv*fi *'!* Itf-i tfji .* M !rfl lllill: I .s*!i`'<* *-v. >*" '* f .L . * 2^&3*|:-.!:<a-:-, x 2 !-> rt> ' : Si!";!';' ~'J. i* 240 THE JOURNAL OF INkWfefc& ivGfEfe i i ; 'i /' 'I; S 3 a* : i $ r2U| changes are present and all grades of bronchiectasis may be seen, in cases of long standing, from simply bronchial and bronchiolar dilatation, with walls still more or less intact, to large spaces filled with pus in which the original bronchial walls have become converted more or less completely into fibrous and granulation tissue. Many of the smaller arteries show obliterative end arteritis. Reversionary metamorphosis of alveolar epithelium is frequent, and such alveoli are often filled with albuminous fluid, in which clumps of "bodies" may be found. Asbestos Dust in the Lungs Dr. W. E. Cooke has supplied (under date of June 25, 1929) details of his researches on asbestos dust in the lungs, and on the constitution of the curious bodies, which have been freely used in the following notes:-- Sections of lung and the results of digestion of the lung with trypsin show an enormous amount of fine black granular dust, much of which is carbonaceous. In addition, there ore two striking features. The first is the almost complete absence of the fine translucent spicules of fiber which make up a great proportion of asbestos dust in factories. The second feature is the presence of large fragments vary ing in length from 10 to 3C0 microns. They are found in fibrotic and necrotic areas, singly and in groups. The particles are so large--masses of them are seen in some sections--that they must have occluded small bronchi and resulted in fibrosis of the surrounding area. Comparing these large particles in the lung with those found in asbestos dust, close resemblance in sizes, shapes, and colors is apparent. There are the same black, blue, brown, and trans lucent fragments.* In fact it is cosy to take such a single particle from the lung and immediately find its brother; in a slide made from the dust. Curious Bodies In addition to the fine granular dust . anil Larger fragments of asbestos, sec-; '.`'2 tions of the lungs show curious bodiep.: 77;; They are found in alveoli, bronchioles, fibrous and necrotic areas, and in phagocytes in sections of both lungs.-. ,V.v ' If a portion of lung is teased and, , ,, extracted with water, or digested with trypsin, or, as Professor Stewart, ~. pointed out (192S), if a smear is made . from the cut surface of the fresh lung,- * V- these bodies are seen in myriads. The y/; larger bodies measure from 20 to 100 microns or more in length, and ore of ^'y - a golden-brown color. They may ,, have single clubbed ends or may vy:; appear as elongated dumb-bells; some are filamentous, while others suggest a| V: v series of disks. . '/'??&. Sidgle coccal and spore-like forms, and aggregations of these, and strepto-; 'j.yy coccal forms are not uncommon; the color varies in the smaller types from a "& very pale yellow to a yellowish-brown. ; ;>V The bodies do not stain with any of the aniline dyes, but in chrysotile workers, they give the Prussian blue reaction for . V;'- iron in varying degrees of intensity. These curious bodies have been found ' in every autopsy in pulmonary asbes- tosis. It would be unprofitable to ; retrace all the steps which led down many by-lanes during the course of' the work, but I will mention a few per-, ' tinent details of interest. . '.' y Professor Stewart suggested to me ! GG I5us J. I. H. . Jum. nio i, * ,, j flB 0007136 j; :.: PULM0NA11Y FIBROSIS IN ASBESTOS WORKERS 241 that a better method than simple the large black, blue, and brown par- extraction of the Jungs with water or ticles and what appear to lie pieces of saline would bo to digest portions with quartz. Relatively few fine spicules .trypsin. During tins process it was arc found; but curious bodies of all v found that if the Kjiecifii: gravity was descriptions arc present in enormous kept at about 1,070, the black dust numbers. And larger fragments of asbestos, as All these facts lead us to imagine ('>well as the partially digested lung the bodies to consist of a central -. ' ^tissue, sank to the bottom of the tube. nucleus of asbestos spicules, upon ' . . .. By decanting the apparently clear which colloidal aggregate of blood supernatant liquid, and by centrifugal* proteins plus, possibly, soluble frac Veiling, neutralizing, and washing the tions of asbestos and, in the case of .../^deposit, the curious lx>dies could Ire chiysotile workers, an iron salt have ./'obtained in a pure state. This was been adsorbed and molded by currents ^ done, and sufficient material for X- in the bronchi and the alveoli. ray examination was obtained. The The method of formation would . -.' bodies were attached to a hair with appear to be as follows: The fine gum and subjected t-o a seven-hour spicules of asbestos cause, by mechan exposure by Professor Bragg's method. ical action on the bronchioles and y;; If the bodies were mineral, the X-ray alveoli, either minute extravasations film would have shown a definite of whole blood, or serous exudates . ^. translatable atomic pattern. The / 'films, however, did not do so, ond we were then able to exclude the sugges/y/fion that the bodies were altered y'asbestos fiber. The result definitely '^-.pointed to tlie greater proportion of . their composition being of nonmineral ^gorigin. v';,;' bulk of the curious bodies is '^'soluble in strong neids and alkalies, and ;:'i)-.if the solution is observed under dark .`.;;;ground illumination, their bases are l'" aeen as extremely fine spicules 6ome of which by transmitted light would y ,^probably-be invisible. Under & dis- setting microscope it is possible par* ":-tially to fracture the larger bodies and .. '-to show a central fine core. The greater portion of asbestos dust consists of. slender translucent fibers. which envelop them. Solution of any soluble fraction of asbestos takes place. The total amount of asbestos that is soluble must be extremely small, as is proved by the X-ray pattern of the curious bodies, but in the case of chiysotile workers some solution is suggested by the free iron reaction. Wo must remember, how ever, that the Prussian blue reaction may be due to the iron of the hemo globin. Any surface in contact with a colloidal solution may act as an adsorbent, and in the present case-the fine spicules must be considered to do so. Interaction between the soluble fraction of chrysotile and plasma proteins takes place, syneresis occurs, and, with the loss of water, the adsorp -"'`In sections and extracts of the lungs tion is rendered irreversible. The ` there is a remarkable paucity of these adsorbent is permanently enslieathed fine spicules. The end-results of diges- with stable colloidal aggregates which :. tion show the fine granular dust and become molded into the familiar *i * Vi VL U -;. k* GG - s-'j-Vv-j.cjJ I. . t;.U . l f'f t, . J * V. ' i** , t a I . ',".-!* . / *%?* . 1 a rv - ..n'-', /-*>:' , **V ' . '' f 1 hi, * , ' : *i "r**-."i'`.- 'C-'V^f3 ' i'P | BB 0007137 | *r ,, ** \ I f 'N* ** ^1' ^ M t ''< V 'icrA : ;^:vC4 M m Sisk' v iS7J}f!r4'.'r *^;?1 .:'r>r '' j*rf *rv \i !p^r;; ), KSti iw&pX'A !5^*'Wa:4^rTVw` vis'i ; 2*12 , f. THIS H3? If T11E JOUHNA^^lwbwiTiekL llVoiENE shapes by alveolar and bronchial cur rents. Support for this idea is found in the fact that micro-organisms adsorb col loidal material in the presence of blood serum and colloidal asbestos. Staphy lococci so treated appear as large round yellowish-brown disks; in the process their property of staining with aniline dyes is lost. The organisms coalesce and form masses; and 1 thinlr it probable that some of the coccal and spore forms are similar .organisms. Finally, are the curious bodies diagnostic of pulmonary asbestosis? Asbestos is unique among minerals in being fibrous; and its dust, generated during manufacturing processes, is also unique. As can be imagined from the formation of the curious bodies, -there is no reason why, given any silicosis, a fine spicule of mineral should not have colloidal matter deposited ' around it and become molded into a . curious body. But as no other min eral dust is fibrous, this occurrence must be so rare as to be negligible from " a diagnostic point of view. The con ditions which, apparently, must obtain , for the formation of curious bodies are . the presence of plasma proteins and fine spicules soluble only with diffi culty. These conditions are ideally found in asbestos workers; for this ` reason I believe that curious bodies, if found in any numbers, are pathog nomonic of pulmonary asbestosis.-- W. E. Cooke and also Roodhouse Gloyne (20) have independently dem onstrated the presence of a mineral core, evidently derived from asbestos fibers, in tbe curious bodies. The bodies have been found (Stewart and Haddow (21)) in the intrathoracic lymphatic glands; in material obtained'/*; j by lung puncture during life, first sug gested by S. A. Henry; in the sputa; and in smear preparations from the fa* cut surface of the lung. In smear preparations they can be readily/ demonstrated. /'**- > The importance of these finding lies in the fact that the bodies have never been found, as yet, in any other:/7"" human affection. That similar bodies may be found to occur in the lungs workers exposed to other dusts, jisr^i^- quite possible, although they have not/;-/^' been found in silicosis, nor were they.-.^l-. present, according to Simson (6), jin ' the fibrosed lungs of a hematite miner. "; They appear within a comparatively short period of time after exposure to.'CY asbestos dust; at the moment, their ; presence in the sputa, in the absence of clinical or radiologic evidence of pul-Y >; monary fibrosis, cannot be taken as io-." at dicating anything more than previous ?j:t inhalation of asbestos dust. The pres- Y\*.T*. ence of the bodies, however, in the sputa of persons with signs of a diffuse fibrosis, or their presence in numbers on/.' X ^. postmortem examination of a fibrosed lung, has evident implications. "it,- -.r- Professor Stewart, who is continuing his work on this subject, has devised the following method of examining sputum for asbestosis bodies: Half as ounce or so of sputum is sdded t'o' v^y an equal quantity of undiluted antiformin.-'Yj'' This is gently agitated until the sputum is completely dissolved, after which it is' /YY'. dilated with 2 or 3 ounces of water and allowed to stand in a large test tube for three or four hours. The bulk of tbe supernatant fluid having then been decanted, the >> remainder is centrifuged at a moderate // speed for ten to fifteen minutes. The whole ' of the supernstant fluid is now poured off, and the deposit transferred to an albumin- \ , *' 3. t H. June. ISIS - GC 15147___ (*BB** 00 07*138 | # /vi* s ``ir -ri *, " ' - --*--J . *' r. . ` . __. M '* .\ i rr TM PULMONARY FIBROSIS IN ASBESTOS WORKERS 243 ; Jted slide, by means of either a platinum loop ora pipette. After thorough drying on a hot plate and final fixation over a bunsen .burner, the film is very pcntlv washed in water, dried, and mounted in Canada bal>um. After a little experience the asbes.tosis bodies arc readily picked up with the low power, and their true nature is then con: finned with the i-inch or oil immersion lens. 'A* a rule they aro present in very small nutn' bera, perhaps only one or two in a whole . .film. In the ease of some of tho older .workers, however, numerous bodies, up to 4one or two per field in certain portions of i'the film, have been found. It is obviously . /'necessary to cleanae thoroughly all glass. .virare, etc., used in making these examina...tiens; otherwise there is a risk of eontami./nation of subsequent specimens. The film* can be treated with hydrochloric acid and ferrocyanide of potash to /'demonstrate the Pmseian blue reaction -vr"/given by the bodies. . /X'.Asbestosis as Occupational . T.V.- Hazabd Out of a total of 374 workers exam- v ined, 105, or 28.1 per cent., were found : to be affected with fibrosis of the lungs, j/ in greater or less degree. But when '' j these figures ore corrected by the exclu- , t sion of cases in which previous work in . dusty occupations (e.g., quarrying, coal . mining} may have been the prime, or a ; contributory, factor in the develop- ment of the fibrosis, ninety-five, or 2G.2 .,' per cent., of 363 workers were found ,, v:to be affected with pulmonary fibrosis y due to the inhalation of asbestos dust, . `and a further twenty-one, or 5.8 per .'cent., showed precursivc signs of this disease. w ` This .percentage may well be com pared with the corresponding figures found by Middleton (22) iu his exami nation of metal grinders (4G.9 per cent.) :and by Sutherland and Bryson (23) (34) in their examinations of potters i . . -V.L n *-N. ( (39.9 per cent.) and of sandstone workers (5S.1 per cent). The precise significance of the lower figure found in this inquiry is not easy to determine. At first sight it seems to indicate that asbestos dust is less potent as a cause of pulmonary fibrosis than are the dusts containing free silica. Other factors, however--such as the measure of exhaust ventilation, or other means of reducing the concen tration of dust, in the several indus tries; differences in the average length of employment of the comparable groups in the samples examined in the respective inquiries; and the relative numbers employed in the more dusty and the less dusty processes--will affect the crude incidence rates ex pressed by these percentages. From comparison of tlic amounts of dust evolved--determined visually and by means of dust counts--in dusty asbestos processes, uncontrolled by local exhaust ventilation, with obvi ously defective exhaust ventilation, and with comparatively good exhaust ventilation, there can be no doubt that this preventive measure, which has been applied in Borne degree for more than seventeen years, has been a posi tive factor in minimising the produc tion of fibrosis--probably in the direc tion of lengthening the period before the fibrosis becomes fully developed. Consideration given to the distribu tion of the workers examined both according to length of employment, and according to age, together with the incidence rates of fibrosis in each ease, indicates the outstanding importance of length of employment (and hence length of exposure to dust), and the negligible effects of age, on the produc tion of fibrosis. Thus age groups 30 to o CO ' ' ' -ur' UJ s* *, ' ..-1 -"`i?`-r*'* - -*- *%/-Ciir I : - -- n v: ;: ' Uj.' ' ; V". . . . .J 1 . ` ,1. ::; / rKt-r> ^ * **&% _________ _I_BB_0007139~7 '"/V.7 cc . *JA'\ 1 ., J tMm .`f**.*r<wr*Wi'-VyA- * 244 . It, , .' ' ' ; < ~o THE JOURNAL OF-INDUSTRIAL HYGIENE 39 and 50 to 59 have incidence Rites of 30 per cent, and 37.9 per cent., respec tively--not n wide difference, since the groups include workers in various processes exposed to different concen trations of dust. Moreover, the aver age length of employment in these two groups, excluding the cases of fibrosis. fibrosis in age group 20 to 29, has been shortened by increased susceptibility at ages under 20. As, however, the > average age of this group of cases of! fibrosis is 26.7 years, and also because the establishment of fibrosis does not necessitate immediate retirement from work, this is largely discounted. TABLE 5.--DISTRIBUTION OF WORKERS EXAMINED WHO HAD BEEN EMPLOYED FOR FIVE YEARS OR OVER, TOGETHER WITH CASES OF FIBROSIS, ACCORDING TO PROCESS IN WHICH WORKER WAS LONGEST EMPLOYED process NO. EX AMINED CASES OP PIBKOSI9 average lenots op EMPLOYMENT IN TBS. No. Per Cent, of Group Group Less Cases of Fibrosis Ca*es of Fibrosis 1. Crushing, opening, disintegrating, and mixing............ 2. Carding................................... 3. Spinning, twisting, doubling, plaiting, etc........................ 4. Mattress mailing.................... 5. Weaving and associated proceases..................................... a. Cloth weaving................... 2S b. Band weaving................... 21 e. Cloth and band and un- classified weavers............ 14 d. Warpers, bAimers, loom tuners, charge hands, and others associated with weaving................. 25 0. Miscellaneous processes and remaining unclassified workers................................ 21 9 39 16 42.9 41.0 8.9 9.1 87 12 15 7 13.8 46.7 10.1 7.3 63 40 45.5 10.0 21 75.0 9.5 4 19.0 10.9 4 23.6 7.2 11 44.0 11.2 24 a 45.8 8.8 10.9 13 2 18.7 13.0 14.1 13.5 9.5 - 12.7 _ .* ,- 10.8 1 , % ,i 13.S Total......................................... 274 95 34.7 9.6 13.5 is also similar, but considerably less than the average length for all the coses of fibrosis (13.5 years). No special susceptibility to the development of fibrosis is shown by young persons, unless it is considered that the figure of 8.7 years, the average length of employment of the cases of The effects of length of employ- ment are such that after five years' exposure, the incidence rate of fibrosis mounts rapidly, and after ten years increases almost in geometric progres sion. Table 5 shows the distribution of 274 workers examined, and of those with fibrosis, according to the process J.LE ) UM, 13W *iL*V- r;- i >.;?' 'S'-'i-v. PULMONARY FIBROSIS IN ASBESTOS WORKERS . which they were longest employed. remains longer in the milder, and '.'This was a compromise necessitated radiologically linear stage. \ by the common customs in tlie indus- This view is evidently of consider- ' by of having several different processes able practical importance since it sug- Spiing on in the same room, and of gests that in such cases, the rate of V''* jokers transferring from one process accumulation of dust in the lung has mc*to uiother., Since the intention was not greatly exceeded the rate of elim ; to obtain some measure of the relative ination, the changes still being centered y incidence of fibrosis in workers in the in the main lymphatic system. l^rwious- processes enumerated, and If this hypothesis is accurate, it /prince no ease of fibrosis clearly due to should follow that in order to prevent ^asbestos dust was found among eighty- the full development of the disease, 'ranine workers examined, who hod been among asbestos workers, within an Tnployed for less than five years, in- a--v-e--r-a--g--e---w--o--r'king~ lifetime, it *is---n--e--c-e--s ^.elusion of this group of workers would sary to reduce the concentration of ;i:'only have introduced a varying source dust in the air of the workrooms to a A'-M error.;' figure somewhat below that pertaining :</v: The processes differ, some very to spinning at the present time. ^materially, in the amount of dust Fortunately, also, the spinning twhieh they cause, and consequently in group is the largest individual group j-.rythe amount inhaled by the operators in this section of the industry--c.g., (f^C30)." The outstanding point brought out of over 400 workers employed by out by Table 5 is the relatively low one firm, this group accounts for more ^incidence rate of fibrosis in "spinners'* than one-third. (group 3), as compared with each of Although all workers examined who f{/:;fhe other groups. They are corrobo- have been included as spinners have , fated by counts of the dust particles been engaged in spinning, or in simi le in samples of air, a number of which lar processes for convenience termed k> 1 5 have -been taken and are discussed "spinning/* for a longer time than on vl^oodcr Dust Risk. any other process, only a few have been -^`t /OThere is also some indication in these employed solely on spinning, and in v > figures that not only arc "spinners'* workrooms where no other, and more likely to develop fibrosis, but when dusty processes, were being carried on. i^'*^,?r:'do, it takes longer to develop. These-two factors, prior work in ' Study of the radiograms suggests that more dusty processes and present ^^.fo such cases (*.., in the less dusty work in proximity to more dusty proc- ^Processes) the resulting fibrosis is, for a esses--especially the latter--have had, ^..considerable period, much more linear radiologic features, and shows ^kssmottUng. The history and clinical y,: ' j .features in these cases, and the com- it is believed, some effect in raising the incidence rate of fibrosis for this group. Dust Risk c parative dust counts, all contribute to In an effort to obtain additional data view that with comparatively low on the influence of concentration of coaceatrations of dust, the resulting dust in workrooms, a number of sam jj; : krosis is longer in developing and ples of air were taken and the dust con- fr, I a*AJk t. , * fyru'T'r /'>?.< < GG ** 50 .m ir ^ v>' *V* '-- !. m * r%#*. 4^ * 11 i&k . v. i/Sv- EfJ-'A If*. `..yi*. .< .i> s > - 4 .. tfe.^5 l,, * a! r *v" i uj ff/J '* f*\l V, a r..- t ; * ? # - ;ii pvj, Iir.V'-"**. .-'foSt '`vivf',.'*^i ii-j '* i **.s * f !C / * yfc'v ; L-r ! *? surV' ^ ` ?"*` i r i':U-!i:.> . i: NOTE: THIS DOCUMENT D!D `.n&sp.FsaM.sj'a.E`M" 246 THE JOT TABLE 6.--SUMMARY OF DETERMINATION OF DUST CONTENT OF <UpfATMOSPHERE OF WORKROOMS AND OTHER PLACES SAMPLE NO. PROCESS AND SOURCE OP SAMPLE LOCAL EXOAUSI VBNTILA TIOR TO PROCP.SS OR NOT OTHER PROC ESSES IN' SAME ROOM KO. OP PERCENT percent-!- PAR AGE aoe TICLES 2m and 7.641 AXT>`~'j PER C.C. UNDER urmtuVi i/. 1. 1/2 Carding; passageway between cards 2. 1/5 Spinning 3. 1/3 Clotb weaving, dry 4. 1/7 Opening 5. 1/6 Sieving; shoveling fiber on to eieve 6. 1/8 Plaiting 7. 1/1 Office 8. 2/11 Office 9. 2/1 Cloth weaving 10. 2/14 Spinning 11. 2/10 Mattress making; filling 12. 2/8 Mattress making; beating, damp 13. 2/7 Mattress msking; beating, dry 14. 2/9 . Mattress making; niter filling 2 mattresses 15. 3/1 Band weaving, wet 16. 3/4 Opening 17. 3/3 CardiDg; between cards 18. 3/5 Carding; feeding card 19. 3/2 Office 20. 4/1 Mattress making; filling 21. VI Mattress making; filling basket 22. 4/3 Emptying eettling chamber 23. 4/4 Same 24. V5 Insulating sections; leveling fiber 25. V5s Carding; side of dirty card 26. V6 Carding; end of clean card 27. 4/7 Carding; feeding curd 28. 4/9 Cloth weaving, very slightly damp 29. V10 Cloth weaving, damp 30. Vll Braiding 31. V12 Spinning 32. 4/13 Office 33. 5/1 Band weaving, dry 34. 6/2 Cloth weaving, dry 35. 6/3 Band weaving, dry 36. 6/9 Opening 37. 6/6 Carding; feeding card Yee No No Yee No No ** a> No No Yes Yes Yes Yes No Yes Yes Yes >., No No No No No Yes Yes Yee No No No No No Yes Yes Yes Yes Yes Yes Yes Yes Yes No * * Yes Yes No No No No No No Yes Yes .. Yes Yes Yes Yes Yes 2,139 1,456 1,756 2.3S4 2,829 1,6S7 901 1.4S0 1,788 1,073 985 970 1,629 1,204 808 2.313 1,528 1,321 1,049 1,858 1,390 3,401 4,711 1,838 81.3 95.9 84.1 0.9 83.0 99.0 98.8 98.7 SS.9 96.2 92.5 85.9 86.9 96.6 96.6 77.7 82.5 82.9 06.3 60.1 * *** s*s ** 95.li<y.'r ' --/di. loo.o.-iy; 96:7. 03.7 r.elfet*;: - 99.0VAir 100.0;^ ; lOO.O'.H* . 98.a.,'-'j.y. 100.0 >:;,: 08.1 95.8-V. : 96.tr*~ oo.^t;- .**& 96.6 07.4^*:"-;. 96.4/fir:< lOO.O^'^V oo.i ; .r^: iXUs'iAtX*r&st*.^ 1* No 1,402 No 1,092 No 1,689 Yes 3,033 * - Yes 758 Yes 506 Yes 954 ... 639 Yes 2,202 No SS5 No 701 Yes 613 Yes 562 ***fcV***.TT1> iI ___i'i':,'-'*- *`. 1<;\ *.**5' *: A*'.-. - ___ ........*r**Tf*VTt. * , -- 4 4 4 ** > ** w._- : J. L B.'^VjV V JuM, ttM ^ : .'V CG 15151 ---JL 001^2 1 .*! ? v*` ,,Vr;. * *;' / **vfr/r-T rrfrryrri '*> *4.f ?-*,***& v.. K.i/i--*: . v.: *' M0^r'r; w PULMONARY FIBROSIS IN ASBEBI^OS WORICEUS = 247 G t d V V. . 1 -L . . ` 1$ TABLE C.--Continued .... ... r. ..,y*iUPtE - v *<> y^-.r' .* PROCESS AND socncs OP SAUPLU LOCAt. exuaost VENTILA TION' TO OTHER proc esses IK SAUE process OK NOT ROOM tro. or PERCENT PERCENT-. PAR AOE AGE TICLES 2/t AND 7.5^1 AND PER C.C. UNDER UNDER l"':Z:3S: 6/4 1 ia. c/s :vV>40.6/7 7"`;Sl.-6/6 7/2 1 f^44. 7/3 i iigis:-?/* 1 7/5 F i^47. 7/6 y 'vt<s;,7/7 1 *^4S.8/2 V ;ri50.' 8/3 l 8/5 Carding; center of room Carding; grinding rollers Spinning Office Cloth weaving, dry Opening; shoveling fiber into box Opening Bsnd weaving, wet Spinning Carding; between esrds Office Cloth weaving, dry Band weaving, dry Carding Yes Yes No * Yes Yes Yes No No Y'es No No Yes Yes G20 Yes 40 Yes 620 * 666 Yes 4.6S3 Y'es 4,880 Yes 6,324 Y'es 5,353 Y'es 6,044 Y'es 4,607 V * 3,413 Y'es 1,2S7 Yes 1,233 Y'es 1,105 e *** .... * *M *ae v> * .... -V, ... SS.C 78.2 67.2 >ae ** *V>* A*** **** *** V..A ....... ....... 04.9 93.7 04.0 '''irtent was determined by means of ^Owens' jet apparatus. Here also the :-^^k:undetermined effect of dust from tiif neighboring processes must be noted. '//Nevertheless some information of prac- f V, T& tical value was obtained. Reference to Table 6 shows that the rxl^eoiiots ranged from 506 to 6,324 t' Vjjuiarticles per cubic centimeter in the I -.'"'/weir of workrooms, and from 666 to * - ;-^,3,413 per cubic centimeter in the air of i^^.'offices associated with the factories. some cases there was a smaller count :V ^hi a workroom than in an office of the y^'seme factory; this was due either to there being much fewer smoke particles !. y.';:in the air of the workroom, or to adher- * >! .`*A;ence of the smoke particles to the ; V.i; inorganic dust in the workroom. !. v I,'--' The character of the dust in the two leases is, however, entirely different. . In the air of the office almost all the ': particles arc black, or brownish, and r-' ./' amorphous, evidently smoke; in the !r ii * . i -f ;;U f. * air of the workroom, the majority of the particles are, just as clearly, crystalline particles of asbestos, to gether with, frequently, some cotton fibers and numbers of black and brown ish particles, some adherent to asbestos spicules and some free. Most of the latter arc iron containing and are derived from the asbestos, and there arc relatively few smoke particles. Iso lated golden-brown scales or plaques, also derived from the asbestos, are scattered about the field. The asbestos fiber first fragments longitudinally, and apparently this process can go on indefinitely, since there is no ultimate fiber comparable to a vegetable fiber such as cotton. The dust collected in the Owens appa ratus contains numbers of these very fine fibers--some about 0.5 micron in transverse diameter, many less--which have fragmented transversely. Thus spicules of very diverse length--up to G ir :j Ji s'- ^ ; 1/ ti u - ..r . ? 't y * t- * * * i? '-' ^ -.r w.**<*.''r/-.fa.y..;v*.. ***." 1 'V ** h rf: is'j'?'-.-:..; n 4. > i ' . .* * * v-*. tO` V I *- C r ...a a-. ..*/ - ` r. * ii * '^V*,r.%.,'V* *' i~ l* . -: i wV p *Vy< . t. ^ : fTf; fk ^ i c *. j`.` ; it*.. y ; .** >, " f" *..*<*!* i ' /V * nO*rTC*ET:V>. ^-;:;;v- JBS? !<ot rnfat r ,j 1 ^ .v*^; 2IS Till-: JOUKNAU cs^lfwbknuAn icyciknk JV njiT-/- :**-ms* nlxnit SO microns--but a)>oiit 0.5 micron broad, arc found in numbers on the sample, together with the black, brownish, and yellow particles already mentioned. The great majority of the spicules are found broken down into particles of the order of 2 microns and less, many being about 0.5 micron and more or less rounded. The proportion of elongated to rounded particles seems to vary in the different processes; for example, a greater proportion of elon gated particles is found in the air near dry cloth weaving than near a spinning frame. Weaving damp reduces the proportion of elongated particles. This variety of microscopic spicules, particles, and frequently some cotton fibers, found in the samples of dust col lected in the Owens apparatus, results in a tendencyto clumping on the cover slip, making counting, especially of the higher concentrations, a matter of extreme difficulty. Occasionally, also, part of the slot of the apparatus choked up with dust. The effect of the clump* ing is to reduce the counts of all except the low concentrations. Furthermore, this apparatus is much influenced by local air eddies and cur rents. It takes a grab sample, which is accurate enough as on indicator of the local conditions at the moment of sampling, but does not give a picture of the average state of the atmosphere during a period of time, as does a gravimetric apparatus. Moreover, with high concentrations of dust, accurate counting becomes impossible! The apparatus has, however, many advantages, including those of con venience, quickness in operation, and direct examination of the nature of the dust. By serial observations, too, temporary and local large increases in tin; dust content of the atmosphere-^-"-'f such as that produced by shovelingV*?y!"' asbestos fiber into a sack--can be'-i*" detected and estimated. This iUs .Bo,f =r-vf great importance since short, but.?!?-:-; repeated, exposure to massive concen-^S^' j t rations of dust is agreed to be veryy.^.- j harmful. Counts Nos. 5, 22, 23, andfjkv.? 43 in Table 6 are examples. Much useful work can be done by means of serial dust counts in various dusty processes in the same factory, and byv^i-^ comparison of the results. . The counts set out in Table 6 derived from eight different factories, and it is a matter of interest to con-^^f> sider whether counts from different factories can be directly compared with one another. Strictly they cannot,^.?--, since the content of smoke particles-.HH; varies in each group. The difficulty#V. might be obviated by counting oidy the particles derived from asbestos. The method has been applied success-y>.?^ fully to counts of crystalline silica^-.^?'. dusts; but it is not so easily applicable ;!/^.. to counts of asbestos dust, which cons<^^! tains numbers of black and brownish''yVv iron containing particles, many' of~><: which are not quickly distinguishable ; from smoke and tarry particles. To classify the processes accu on the basis of amount of dust evoivea,^^^ it is necessary to take serial samples at'^J\^ intervals corresponding to the details&{$! and complexity of the processes^V-'^v With some straightforward processes, such ns spinning, few samples will # ` 'x* *7* plant--in which the evolution f dustj'-i-^ rises and falls rapidly in a (toropara^&Ay tively short space of time, many morep*-u. observations are necessary throughout1 v^. . J. L ".'jiff: w. . 5 153 .xm _________ "\ BB Q0072|i  V* PULMONARY FIBROSIS IN ASBESTOS WORKERS 249 a shift, to determine the average cou- when asbestos tape weaving dry, and ` eentration of dust. Repeated controls only once a day when weaving asbestos ire also required. wet. ' Comparative, data show that the Next in order comes mattressmaking, . dustiest processes arc opening (with without .any precautions such as ex Id-fashioned teasers), sieving (with haust ventilation, or damping floors, bo local exhaust ventilation), and doth, and tables. Application of ex ... shoveling, or otherwise haudling asbes. toe .fiber. The heaviest counts of all .", were found in this group, in filling sacks, haust ventilation and damping reduce the count considerably, but it is be lieved that the figures are too low, since . _\,by hand, with disintegrated fiber in a counts for some subsidiary processes * settling chamber. The visual cloud of such as buttoning, sewing, and cutting f dust was intense, and irritating enough out ore not available. . 'to provoke immediate coughing on the The figures for spinning, plaiting, part of the observer. The clumping of and braiding are believed to be rather ' ,- v. thc dust particles of the sample on the too high, owing to contamination of w -/cover slip was very marked, with the dust from neighboring and more dusty .V result that the total dust count arrived processes, and further investigation is ;at`~waa undoubtedly too low. With required here. ` ././counts' of asbestos particles of this A number of the samples taken with /'.order, however, the precise count is of the Owens apparatus were examined . .' Bttie practical importance, since the to determine the size of the particles, : dust concentration is far beyond the and the percentages of partidcs 2 safe limit. microns and under, and 7.5 microns .Next in order is cloth weaving, dry and under, were ascertained. The 2- / ;.nd without the application of local micron standard was retained for /'exhaust. This is undoubtedly a dusty purposes of comparison, and because /. '.process, and although local exhaust of its accepted importance in silicosis. i.. - ieduocs the count at the breathing level The 7.5-micron figure was also adopted the weaver, much dust still escapes because of the pronounced acicular .y' /into the workroom. Further counts are character of much of the asbestos dust, ' V"' v; necessary to estimate this. Weaving and because, representing the diameter doth wet, not merely damp, reduces of the human red blood corpuscle, it . :`V' /:the dust count to a remarkable degree. is a standard easily distinguishable, ';?r -The`figure for band (*.e., narrow) and may conceivably represent the ^^wring, wet, is not accurate since it limit size of particles which can be con ?v-/K'w*s raised by dust from a neighboring veniently engulfed by phagocytic cells, :-rdry doth loom; still the improvement which are somewhat larger. Among * // due to wet methods is noticeable. One `twenty counts from various processes . ` ubestos weaver, who was formerly a (Table 6), in two, between 60 and 70 ' 'cotton weaver, and who has to wear per cent, of the particles were of sizes glasses, stated that whereas he used to 2 microns and under; in two, 70 to - dean his glasses about three times a SO per cent.; in ten, 80 to 90 per cent.; . day when cotton weaving, he has to and in six, 90 per cent, and upward. - deap them about five times a day When the counts were analyzed ac- ' f >> m: - - ' / -- wvr m-..vcv :' 'mmTM i : v.:* X.. * 1 Vv.'V-.iw ^:3ci.5i ' .J-'j i 1 m-- -'>.V :.: - vmMI 'V'* , ' i\\ PrfjiL. :> t. gft GC 15154 : .***"fa# *X\_ `- --J?iL22071!'5*7'l WfettWO*:: i i: . -.ri 5 #" v > IJ .: '3 . J*i| t/i1' HV, >'< 'l- iu .j. :\\ a *JSJ j 3 i !wa>' '? 1's* i " *" ;: I' .*.Vft' 'it>! ,vV, .\?v *j m i *'* .*r*^s ^ iTi'J l-. f-y f.Ti - y-iS fe-'rU. . vmw& : rt ^ *r**s I * I'imh.*.. s';. ' ii . '? :P nj-7-.: , ;`.:.J4 V.11I ,-i '..i -; iiUfes;.'! 250 TIILC JOURNAL OF INDUSTRIAL HYGIENE cording to the 7.5-micron standard, all twenty showed 00 per cent, or more of thc particles to be of this size or less. With regard to the effect on the lungs of different varieties of asbestos, rno evidence was found to indicate that any one of its varieties is more potent in producing fibrosis than the others, other factors, such as concentration of dust, being equal. There is now no doubt, however, that both chrysotile and crocidolite will produce fibrosis; while the third, the comparatively newly discovered araosite, resembles crocidolite so closely in its chemical constitution, and in the characteristics of the dust, that there can be no reasonable doubt, also, with respect to it. Length of Dust Exposure No case of diffuse fibrosis clearly due to asbestos was discovered with under 5 years' employment. Three cases were found with 3, 3J, and 41 years' work, respectively, who showed clinical signs of fibrosis. Definite confirmatory radiologic evidence was obtained in the first, definite but slighter radiologic changes in the sec ond, and indefinite suggestive changes in the third. The previous occupation in the first case was flax weaving for IS years; in the second, coal hewing for 16 years; and in the third, work in an iron foundry for 1 year. All these occupations are dusty; and in the lost two there may be some exposure to free silica. Also increased silica con tent has been found in the lungs, after incineration, of flax dressers. For these reasons, these three cases could not be certainly ascribed to asl>estos dust, although it was, probably, at least a contributory factor. Among the cases of fibrosis found, thirty-six ,, had been employed in asbestos for `~ periods ranging from 5 to 10 years; -- two of these coses, one employed for 9 .* years and the other for 7 years, show that a considerable degree of fibrosis may occur with less than 10 years' - exposure. K W. Simson (6) examined the lungs .: of a guinea-pig which had been expert- mentally dusted by Mavrogordato for...v two hours a day on each of fifty days between February and April, 1925, i> - and which died from other causes in"'-?.' December, 1927. He states that his- Vv- tologic sections showed a slight gen-.:-7 eraliaed fibrosis. This observer also - examined portions of the lungs of two native asbestos mill workers; one had. - 7 been employed for twelve months and' * had died from a biliary tuberculosis, 7; and the otherremployed for two years,.7 i-- had apparently never recovered from 77 an attack of lobar pneumonia a year, .7.,. before death. .I' ifV: In commenting on the amount ofT'V fibrosis found, he states that "a com* ,7, parisoo between the human cases and-7. * the experimental animal showed that:.--- the fibrosis was more rapid and exten-7 sive in the human cases than in tbe..`.`<\;` expnerimental animall,." and,. maaginain,.. tha1t "the amount of fibrosis in two of |V' 7 ;. the human cases . was quite. definite, and, if due to the presence oP-*:*' '.* asbestos dust, the initial rate of pro-'-i duction was rapid when compared with'if" I present-day non-infective silicosis on T-7 1 the Rand." \\ Experiments by Professor Beattie,*''-.\ j in 1912, demonstrated that the lungs-;; * i of guinea-pigs exposed to asbestos dust\ for forty-t lire*- and sixty-seven hours ` J showed "dflinitv cellular proliferation, " , ; though not very extensive, and this is ; 7` / t NOTE: THIS CV5'>- NOT 010 J, L B. Jww. I ,'G FILES CG 15155 PULMONARY FIBROSIS IN ASBESTOS WORKERS . 251 certainly a preliminary stage in the contributory factor. In six of the , production of fibrosis." eight cases the diagnosis was verified These pathologic and experimental by postmortem examination; in the findings suggest that the inhalation of other two cases, confirmatory radio- asbestos dust rapidly causes some graphic evidence was obtained. changes in the lungs. But no evidence Information has recently been ob . was obtained that asbestos dust can tained in regard to three other cases, produce an acute type of fibrosis com- in which death occurred in 1929. The ; parable to that formerly noted in details of one have been published by South Africa after repeated exposure Wood and Page (25). Postmortem O C/5 ; to massive concentration of free silica, a few cases of which have occurred recently in Great Britain, causing * . death in from two to four years. \ The amount of disablement pro ducedby the development of pulmo- nary fibrosis in these workers is surprisingly slight for a number of years, even examinations have been made in all three cases,, and in all, the presence of Q pubnounry asbestosis, without tuber jTM-- culosis, was verified. In one case, the pulmonary fibrosis was the primary SZ UJ CD Q_ cause of death; in one, information as Q_ -oWtv to the extent of the fibrosis has not yet no** v-D been obtained; and in the third case, a o more so than is generally the case in silicosis. The nature of the work, however, in the majority of the proc esses does not involve much physical ` exertion--in fact, in this respect it is `light work." The affected person maj', and often does, continue at work ' --with - occasional intermissions, lat terly, due to exacerbations of bron lobar pneumonia was superimposed on the fibrosis. It is not suggested that these few fatalities, in which the cause of death has been verified by strict inquiry, are any criterion of the true effect of the disease on the mortality rates of asbestos workers. Others are known to have occurred in which the exist O QC L.U -Tr s CD h-- O O' wear^i chitis--until the condition is advanced, ence of the asbestos fibrosis has been although he suffers increasing incon determined in life, but no postmortem venience from shortness of breath on examination has been possible. the slightest exertion. ....Usually these cases cease work a year Difficulties in Diagjiosis w more before death, but sometimes a -`'terminal bronchopneumonia, or'other acute infection, commences while they * are still at work, and there is no long period of invalidism. Many factors have contributed to impede both the recognition of indi vidual eases of this disease, and the establishment of asbestos dust as the determining cause. These factors are , - Fatalities Particulars of eight deaths Imvc been collected, and are smnmnriml in Table 7. In six of these, advanced pulmonary fibrosis was the primary cause of death. In the remaining two eases, pulmonary tuberculosis was a consequent, partly on the nature of the disease, partly on the nature of the dust, and partly on the industry itself, its rapid growth and internal condi tions. Difficulties in diagnosing the disease, its points of resemblance, in its latest stages, to fibroid tuberculosis, and the liability of those affected to be Tit.lt GG 1 t v** i > ;; ,,v '-'Vi*,-y r a1 ' * . * ^ ,, 1S',% - **?*:. & i 'Vi* d] #j - * r ,s-v.4 !I \ T4` 3r IhI j-j . $1 $.*IZf*y,*fTdt&*.' .-4 -;' -. -- - -=* * } r vA > /-: 1- ' '; m*&$ ti. -^j -- s& '''v-4t.^,jSh*.^(4^Cni .M' -fj.A4"a' /-i 1f .*- 7`fcVV.fllt ^ ****** alVwiMl HAijirASp'.V f-^ o.:.vi t, V; r?/*>? .HQ# 'i-vr- A--7' r'V ~~^*"'```V*T1'^-'rt"Hr jr'r4rKy****>.-J-r~-.--`-*r->J*-~ * - xi':; ^^'::.: y** ^ V' *v : . *: ` ; IiSSI* SfcP WIV i>*.7wi5~ vW*t*^ j-- * vcC_D^; iV*5 ca I ___ hit' I 03 I , -. fat i i <~n sVi1 * * -- r.}, JoJ Cn n 3i ^ feiS !-! M" ! ^! !iw: I ! .V. I-- | - H ..It TABLE 7.-PARTICULAHS OP FATAL CASES NO. CASE DATE OV DEATH1 BEX I. Montague /13/1900 M Murray CftSQ 2. Cooke's ease 3/14/21 P 3. II. S. 1927 F 4. SI. S. 3/ 7/27 F 5. Grieve'* ease OV. L.) 6. SI. M. 3/24/23 8/25/23 M F 1. J. C. 8. L. H. 10/13/28 M 2/ ~/29 P TltS. AOE EUr Loved uain fdocess CONDITION or LONOS F03TMOnTEM EXAMI NATION IN QUEST nEMARES 31 14 Card room 10 yra. Advanced pulmonary Yes fibrosis; no tuber culosis 33 . IP Spinner latterly Extensive pulmonary Yes fibrosis and tuber culosis IS 24* Mattress maker Pulmonary fibrosis No and tuberculosis 31 204- Mattress maker 31 13* Mattress beater 34 15-16 Mattress maker Chronic pulmonary fibrosis; no tuborculosis Advanced pulmonary fibrosis; terminal bronchopneumonia; no tuberculosis Advanced pulmonary fibrosis; no tuber culosis Yes Yes Yes 30 18 Weaving lyr.; mat Advanced pulmonary No tress dept. 7 yrs. fibrosis; no tuber and 2 mos. culosis 41 19 Mattress maker Advanced pulmonary Yes fibrosis; no tuber culosis No No Exposed to dust from other proc esses. No Two radiograms con firm diagnosis of pulmonary fibrosis. No Yes Yes Worked for less than the period stated, as a mattress maker. No Two radiograms con firm diagnosis. Yes Xi -*: o GO . <t * r .Cv. i !*'" *.4i * PULMONARY FIBROSIS IN ASBESTOS WORKERS 253 jtV ferried off by some intercurrent dis- asbestos only for comparatively sliort i ' ease--which alone is noted onthe death periods, and of the processes considered f\~w certificate--arc all of iniporta nee. v ":-,A concrete example encountered ' *.. during the inquiry will illustrate one of so far, tlie less dusty spinning group is at the same time the largest. Thus only now the existence of a health risk ! these points. J. C., Case No. 7 in in the industry is beginning to be ^ v;'.:.Tble 7, was known by his own doctor recognized. and bythe Chief Tuberculosis Officer of the town to be affected with advanced Docs Asbestos Dust Predis * `jt.tfibrosis of tlie lungs. Four or five pose to Other Pulmonary months before his death it was thought Diseases? ; , that a change of air would be of The important question as to i . - advantage to him. Through the gen- whether asbestos workers show an in ;' Iv _ .erosity of the finn with which he had creased liability to other diseases of :;*:^been employed, he was transferred the lungs, such as pneumonia, pleurisy, V -li, ..from the town to a farm in tlie country, and pulmonary tuberculosis--espec I. ^^Xwhere he died. The death certificate, ially the latter--requires further in i-.`V,'given locally, stated that pulmonary vestigation. 1 -^tuberculosis was the cause of death. A history of pleurisy was given by -i In another case chronic bronchitis was ten workers, in eight since commencing given as the cause of death. . work in asbestos; in addition, one . , I.`. In the less advanced stages of the worker had a slight pleural effusion at ~j- ' .-. disease, the symptoms are so unob- the time of examination, and one truKive that the worker rarely consults showed signs of old pleurisy, but no *K7* `'*bis doctor. In tlie later stages, ^ chitls, or tlie supervention of bronacute history was obtainable. Of the two with attacks prior to work in asbestos, ;r .* 'bronchopneumonia, pulmonary tuber- one had normal lungs, and the other * ' culosis, or other acute infection, all so showed signs of a bronchiectasis. -Of -v much more common, masks the under- tlie eight giving histories of pleurisy, ; . lying fibrosis; and the terminal condi- three showed signs of fibrosis, four . \. V.tion is noted as the cause of death. showed signs of the old pleurisy only , S fu the second place, the silicate dusts (one being due to a gunshot wound S. wbicli asbestos dust is one--repre- during the War), and the eighth .v.Koting silica in the combined form as showed signs of an old inactive tuber :-/: PPsed to free silica, have naturally culous lesion of the right upper lobe. ). ; been verehadowed by the silica dusts, A history of pneumonia was ob ' `since they do not produce the picture tained in sixteen workers--in ten prior , . \ f silicosis and have not been shown t-o to commencing work in asbestos, and : "be associated with an increased mor in six since. Of these six, two showed tality from pulmonary tuberculosis. signs of a thickened pleura only, one Moreover, although the asbestos in- showed merely enlarged lung roots, = dustry has very rapidly expanded, it is two had diffuse fibrosis, and in one the still comparatively small, and scattered lungs were normal. Of the remaining over tlie country. A large proportion ten, one had a thickened pleura, two i' the workers have been employed in bronchiectasis, two diffuse fibrosis, one 1 V*L 12 ` K. | ' *' .**.''** 1 .:`wiyw: O GO -- lu : O ^ -- L- TMi_l--- ; rr\ O/: I*?7- ' i [ , . --- --'U. < ; -'sSri r;- O?* ` ~ ; 4 f! - 1! )' \ ' - - ';: cr** > 'V y Qm it * . . - ` * J ,1 \ i s * f *- U * '* 1|* ..' '%'v>-VA' ` * . Vi? * * * TA>* i`.*f *v` * ' /' t i ' -J'? ' i;vr-. : \ffl\ *' i-.r*-*'V*> * :1 . * iif !* * ' M * j;;, :* *\' ar*.r>' .7.-i*' `TM ** * , * . *. _ '/ 1 m"t? ; S- ` %. *. ' ;r _ : * . r\ : i*4* wi*'1 . i; .-./v^Vt-V7^S'Assri5j . ! : 5 :> .. ?** i 1 at * _ . ` m ; * r *' - ; r\m . ' _______ *! * r,` !? #i*y, I BB 0007149*7 -n "II a. # _;! - "f'i GG 15!58 1.", commencing fibrosis, and in four the lungs were normal. With regard to evidence of bron chitis, and bronchial and pulmonary catarrh, fifty-eight of the 363 workers (16 per cent.) showed signs of one or other of these conditions, all being quite mild. Of these, thirty-one also showed signs of diffuse fibrosis, repre senting 32.6 per cent, of the fibrotic group, and eight were in the prefibrotic stage (38.1 per cent, of that group). The fact that the clinical examinations were conducted during the warmer months of the year, no doubt operated to reduce the incidence of these com plaints. Under the circumstances, the preponderance among the cases of fibrosis is the more noteworthy, as in dicating persistent irritation resulting from the dust. Of other diseases, eight gave his tories of rheumatic fever, and of these, two had definite valvular disease of the heart. In addition, valvular disease of the heart was noted in one worker, but no history of rheumatic fever was ob tained. With regard to pulmonary tubercu losis, bo definitely on added risk in sili cosis, this disease group bos been drawn up to include nil workers pre senting signs indicating a past or pres ent pulmonary tuberculous infection, but excluding cases of old inactive hilar tuberculosis. Under this heading are included not only workers with definite clinical signs of active tuberculous lung infections, or of old inactive lesions, equally definite, but also those workers showing signs of old apical col lapse, usually attributed to a past tuberculous infection. Signs of the latter are not uncom monly found in quite healthy persons, and are of no importance unless it isl&'i shown that the inhalation of asbestos;^' dust is associated with pulmonary**).'.;, tuberculosis to an increased degree,^;;, when such coses, as indicating a group} of workers with a latent mfection^!;r4 would assume a greater significance.' No close association is apparent, how-cl ever, since only thirty-seven, per cent, of the 374 examined, showed^-TT-? evidence of this disease, excluding casesi/X^ of old inactive hilar tuberculosis, evearjj* when those showing the minor changes mentioned above are included. only four was there a family history, of*}?- pulmonary tuberculosis; and three out of four active cases belonged to group. Thirty-three cases were inac-;^rtv tive, of which twenty-one presented no-.ST-' evidence of dust fibrosis, and twelve^vT.-l presented evidence. Out of the 374 persons examined,*^!-) fourteen, or 3.7 per cent., gave-* J&Zi family history of tuberculosis. 'EvvS>*:' dencc of active pulmonary tubercu^Sfev losis was present in three; in two these three the source of infection appears to have been a near relativ'fcSsf?^ Thus, no outstanding susceptibiUtyrj-^ to pulmonary tuberculosis was'`dis4/.r clos_e_dl , _e:ijtIh__e__r__a__m__o__n_g___a__sibesAto---s---w----ojr.k-ie'Krsf*ii*S?'i?f os a class, or among those with fibrosis^i^Jf; considering the frequency of old healed.fev apical lesions among the generai^fc: population. We have, however, by no means dis-^S' posed of the question. The superven^^J tion of a tuberculous infection'on. lung already the subject of fibrosis duces an increase in s>Tnptom,s,-;pre^^:_ viously unnoticed or disregarded,'ahd^^l causes the worker to seek his doctor's},^ advice. He is then appropriately.^^, advised to give up his dusty employr.*s3 ment, migrates from the industry, GG 15159 i'B8^0007isQ~T;^P iUkiiV/; H;,'" ' .r.V ^ - , pir t' -- i - --- -- sfr\ '41 *- . ****. PULMONARY FIBROSIS IN ASBESTOS WORKERS 255 or may not accept sanatorium produce a serious and even fatal degree 3 4 ^'""treatment.. Thus there lends to be a - -fir drift of such cases from the fibrosis of pulmonary fibrosis. 2. The type of fibrosis produced, TOJT , producing industry. however, exhibits a number of diverg . During the course of the inquiry, ences from that caused by the inhala % p^-7; information was obtained of a number tion of free silica dust, and the outcome '-persons, previously employed in of these variations is not yet apparent. i^V-asbestos, who were either at home or in 3. The divergences noted so far are f&^waatoriums, suffering from chest com- exhibited in the radiologic picture, i}l)irt^p7lpalmintia'.'W.Whheerree an examinathion of and on postmortem examination of workers is confined to those at w<ork, a the affected lungs, both in the gross It-'; l^wv'eeeCrTtaWiinin noumboecr ouif aiudivvauniiceud ca:ses of morbid anatomy and in microscopic j|^:5brosis, and a certain number of cases sections. pulmonary tuberculosis, with or 4. In the latter case the appearances 1/fiV; twithoutan asbestos fibrosis, in persons of the asbestos fibrosis seem to be r-.t-i.- Who have either given up work, or who sufficiently distinctive not to permit tart; off "work temporarily, will be of confusion between it and silicosis. &! Snissed;;^- 5. The radiologic appearances of the asbestos type of fibrosis, even in the more developed stage, are more deli cate, softer, and more diffuse than the y'. It isi necessary, therefore, to leave silicotic fibrosis. ;tlusquestion of increased susceptibility 6. It follows, therefore, that an 1* pulmonary tuberculosis in abeyance, opinion as to the degree and intensity f.^*;pending further investigation. of an asbestos fibrosis, based on a com , respect toany increased susccp- parison of the radiologic changes with K~y 'libilitytothe supervention ofotherlung those shown in standard silicosis films, /.'diseases in workers with an asbestos will be an underestimate. [T'X' fibrosis, the data obtained were insuffi- 7. In the absence of a full medical auy conclusion, except and industrial history, possibilities of x** bronchial catarrh. There are in- confusion of the two tyi>cs of fibrosis .^^^dications, however, tliat when pneu- will arise in the interpretation of radio ' bronchopneumonia super- grams. on a fibrotic lung, the prognosis 8. There is evidence that other in organic dusts, containing no free silica, ; -^WtosisakdSiucosis Cox-dusted may be productive of this fine type of fibrosis in varying degree. ^ew relationship l>etween **hestos fibrosis and silicosis, since ^s?*9!:are'both varieties of fibrosis of lungs caused by the inhalation of Summary 1. There is a definite risk of the development of a diffuse pulmonary se<3nB desirable to summarize fibrosis in persons exposed to the in ^^L.bertlythe main points of similarity halation of asbestos dust. dissimilarity between the two dis- 2. This risk varies directly as the 'tS> i,yes *o far as has been ascertained, length of employment (and hence j^' Inhalation of asbestos dust, under . favorable conditions of concentration of^dust and length of exposure, will BB 0007151 *1 i;. : W''Ai'iV'1 " '"'l i 1 1 'I " W l  to* ;sU>ev. -; .. fa# 3 i';<3 it''..!' ' >-i4M*1lS>l-'T-'.i**-f.'":-.4?,.:' :. ~**4 A *r*.i ,-*fc. > :-; IPi^STjY 5/V^VrJ^ f 'Sfrju** pMY- ksd i\?>.\ ,-i!'..s [4c.jj *n#Ni * -' J.^ul v <# * m *r '/'V ] ( k;-*4*-.dS /72t,-fa- g.-yui1*^'j.iiKWi*T\ftTfc,-^*/*; 3a. MOTE: ;-OC. ' 1 *' r-sr 25G THE JOURNAL O HYGIENT5 ; ?*: length of exposure to dust), and is unaffected by the age of the worker. 3. There is a considerable difference between the least dusty and the most dusty processes investigated, and there is a corresponding variation in the rela tive risk of the development of fibrosis in the workers in these processes. 4. With continued exposure to high concentrations of dust, the disease may be fully developed in seven to nine years, and may cause death after about thirteen years' exposure, exceptionally in a shorter period. 5. Fibrosis as it occurs in asbestos workers differs considerably from the disease as it occurs in workers exposed to free crystalline silica dust; it differs in the radiologic picture, and also on postmortem examination of the affected lungs. 6. The more dusty processes are those involving the preparation and manipulation of the raw asbestos (other than crushing), dry cloth weav ing, and mattress making. 7. The less dusty processes are spin ning and similar processes, and proc esses, other than dry weaving, in volving the manipulation of the spun yam. 8. Further investigation is required to determine whether there is any in creased susceptibility to the superven- tion of pulmonary tuberculosis asso-;' cisited with the development of the :- asbestos fibrosis. <" Much generous assistance has been rs-< _ ceived from many sources during the course *T of this inquiry, and for this acknowledgment". 2 is gratefully tendered. * In addition to those already referred to, ;' the writer is beholden especially to Dr. S. A. )/ ~ Henry, who did much to facilitate the inves--'' tigation, particularly by his detailed reports > ' on various relevant matters, and by much*/ , organization and liaison work; to manyV.a others of his colleagues in the different dis^ = triets, to a number of directors and officials. r / of various firms, foremen, and employees;-^ to Dr. W. E. Cooke of Wigan and Professor.:/ M. J. Stewart of Leeds for pathologic mate-Y. rial and for much information as to the > progress nnd results of their own researches * into the gross anatomic and the histologic.:, features of the asbestos fibrosis, and the'i': constitution and location of the curious -TM* bodies; to Dr. MacGregor, Medical Officer/;/* of Health for Glasgow, for various clinical ` and radiologic facilities, and for his ever*;/' present readiness to lend the aid of bis-V o Department, and especially to Dr. H. Seiler of his staff; to Dr. J. C. Robertson for;:' the loan of a radiogram, together with *.. detailed clinical notes of one patient and^ other valuable information; to Dr. W; H. {- Bateman for the loan of a radiogram, for ? * some clinical histories, for obtaining and^ examining several specimens of sputum, andA-. * - for other aid; and to Dr. J. Rennie, Chief.V, Tuberculosis Officer at Sheffield, for a seriesY - of radiograms showing various stages ofV` silicosis. BIBLIOGRAPHY1 -m #*wJ' 1. Departmental Committee on Compen 4. McDonald, S.: Histology of Pulmo-'T sation for Industrial Diseases. Min nary Asbestosis. Ibid., p. 1025. ' 7';' utes of Evidence, Appendices and In 5. Seiler, H. E.r A Case of Pneumocooio-J dex, 1007. Cd. 3496, p. 127; Report, sis. Result of the Inhalation -oD 1907. Cd. 3493, p. 14. Asbestos Dust. Ibid., 1928, f, 0S2. 2. Cooke, W. E.: Fibrosis of the Lungs 6. Siarsox, F. W.: Pulmonary AsbestosisT Due to the lubslation of Asbestos in South Africa. Ibid., 1923, I, $85... Dust. Brit. Med. Jour., 1924, , 147. 7. Royal Commission on Metalliferous ^ 3. Cooke, W. E.: Pulmonary Asbestosis. Mines and Quarries. Second Report,'' Ibid., 1927,5,1024. 1914. Cd. 7476, p.146. -j- | BI3 0007152 | J. L H.. Jum, UM> ' GG 15161 'ti .at# `* 0 'I V PCLMONAHY FIBROSIS IN ASBESTOS WORKERS 257 ,. ^ 'Vi hueb Jianr j dit- ' * \ ' Annan, C.: Note* on a Fino Type of ~ ' Fibrous Fneumonokoniosit Produced and Other Minerals. __ Indust. Hyg. No. 13, Rep. '^^'Dir.'Cen. Fob. Health, New South -j;:Wales, for 1827, Section I.-E, Indust. K&^'Hyg, p. 102. Sydney, 1929. pjg? (ynx, W. I.: like Dust Hazard in the "iAt^ii Abrasire Industry: Second Study. 1920,11,92. -^#.'?AX00Arr, H. K., axd Pendergrass, E. ' Pa Pneumoconiosis (Silicosis). A Roentgenological Study. New York, 1 ^ x.f'pbul B. Hoeber, Inc., 1926, p. 155. F^^IU'AfOitrsow, L. R-, Brttndage; D. K., L^'/r.' RtJSS,!:LL, A. E., AND BlOOUFIEU), J. J-: The Health of Workers in Dusty Lj'.Tf'-S.Ttsdcs. I. Health of Workera in a r 0i' Portland Cement Plant. U. S. Pub. Health Bull. No. 176,1928. \;%*!2.,Gooit, 3L W.: Fibrosis of the Lung in >1. Iron Miners. Jour. Roy. Micr, Soc., ^>;'`tl1925,p. 432. r^ij''Annu*i Report of the Chief Inspector of v Factories and Workshops for 192S, p. London, H.M. Stationery Office, .aJ>^14/Pekk7, F. W.; In "Industrial and '^V.'yMaauIacturiag Chemistry" by G. :i.> ;/;' Martin. *-1917, Part 2, p. 281. ' '"7 Ik-Compiledby Asbestos, a monthly trade *nd ` published in Philadelphia, Pa. Statement of the Trade of the United. Kingdom, for 1922 and 1927. ^VLondon, H. M. Stationery Office. Tj^^JJj'Tlopartracntal Committee on Compcnft tation for Silicosis dealing with the l"L^';?'Rfraetorie Industries (Silicosis) iSeheme l919. First Report, 1924, p. A- R-: Silicosis smong Rock '5' IWUen, Blasters, end Excavators in Tork City. This Jour., 1929, 10* '**' *: Pulmonary Asbestosis. ' Tubercle, 1929,10, 353. "e, 6. R.: The Presence of the ^Y^V^^Bestoa Fibre in the Lesions of . j ^beiioe Workers. Ibid., p. 404. .^**!&if&7*.-.V *r > ' 21. Stewart, M. J., and Haddow, A. C.: Demonstration of the Peculiar Bodies of Pulmonary Asbestosis ("Asbestosis Bodies") in Material Obtained by Lung Puncture and in the Sputum. Jour. Path, and Beet., 1929, St, 172. 22. Macsun, E. L., and Middleton, E. L.: Report on the Grinding of Metele and Cleaning of Castings with Special Reference to the Effects of Dust In halation upon the Workers. London, H. M. Stationery Office, 1923. 23. SniEiuNo, C. L., asp Brtbok, S.: Report on the Incidence of Silicosis in the Pottery Industry. London, H. M. Stationery Office, 1926. 24. Sutherland, C- L., and Brtsok, S.: Report on the Occurrence ef Silicosis among Sandstone Workers. London, H. M. Stationery Office, 1929. 25. Wood, W. B., and Page, D. S.: A Case of Pulmonary Asbestosis.' Tubercle, 1929, 10, 457. For the geologic and the manufacturing and industrial aspects of asbestos, see: 26. Cikeel, F.: Chrysotile-Asbestos, its Occurrence, Exploitation, Milling, and Uses. Second edition. Ottawa, Govt. Printing Bureau, 1910. 27. Asbestos, its Sources, Extraction, Prep aration, Manufacture and Uses in Industry and Engineering. Berlin, Becker and Haag, 1923. 23. TnoRrx, .: A Dictionary of Applied Chemistry. London, Longmans, Green A Co., 1912. 29. Asbestos, a monthly trade journal pub lished in Philadelphia, Pa. For description of processes, and further discussion on the incidence rate of fibrosis, and effect of work in different proeeeees and also preventive measures, see; 30. Mckewetexh, E. R. A., and Price, C. Vi.: Report on Effects of Asbestos Dust on tbe Lungs and Dust Suppres sion in the Asbestos Industry. Lon don, H. M. Stationery Office, 1930. O O: * "'F^viy i ; .!:*f.t .*.*, **v* * ..* % v. ' ii.v'v-riizwifr '# :.!rterrw *0* * .,. -ei\4^.r`Y.' /M*^3 ,1 I -* 4f *\ .7 : ':R * * .tO*. 4 l*f rifA\ 7^?.a;, ,S.frv:.- `JX& - . 4 I. ^Ss* ` ,**,* T* . V** ** I BB 0007153 ..IL2 . * r-tvi- Arr'J it ( *1* *7*lvr."( . ** I 4g