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. S. TREASIRY DEPARTMENT PUBLIC HEALTH SERVICE Public Health Bulletin No. 241 August Uc'.N A STUDY OF ASBESTOSIS IN THE ASBESTOS TEXTILE INDUSTRY By WALDEMAR C. DREESSEN, Passed Assistant Surgeon J. M. D ALLAVALLE. Passed Assistant Sanitary Engineer THOMAS L EDWARDS. Technical Editor J. W. MILLER, Pathologist R. R. SAYERS, Senior Surgeon With the assistance of H. F. EASOM, M. D,, Director M. F. TRICE. Engineer rf i r u tu n tr ia t H y a ir n e . .VwtA t'nrilinn S ta te Hnnrti n f H+atth Front the Division of Industrial Htgiene National Institute of Health PR EPA RED BY D IR EC TIO N OF T H E S IR G E O N GENERAL [ E x it e d sta tes GOVERNMENT PRINTING OFFICE W A S H IN G T O N : 1938 For sole by rhe S upenotenderu o f Itw ooreoM . W ashington. II. t ' ...FJCtfli w.*-me l*rtce 20 cents /'.itC C ORGANIZATION OF THE NATIONAL INSTILETE OF HEALTH T homas P a khan, .S *<ju.m -ir/, I Public llmUh S'. L. R. T hom pson, .is s i- U /ii S .rjrt..., tr-f,tr<iL Dinclor, Xoliunnl hn-ldnh <f fhniP. ' IHitsion o f Bi-'!<"jic s Coiti p>{.-- Ci. t :. Spninr Sunt. W. T. H arri~ov, D h h 'tm o f I'li "i ' d r -- CMft, Pr< r C. S. H udson. D icifon o f / '/-'*, f. ' t i . i u r Sura. R. E. D vlk. tirisinn of ['. ! / / w<. m.-- C- !. > : > r Sunt. R. R. S O Liu. Itirifion o f Po.'.' t.-- C ;a S ,r .. R. D. L i t u i : . Ih'riit'oH o f P l l,i ,, -- C u r t . P : a r i u f i ' l i w s t Di ret'I or C Mil VoF.urt.iN. WriWo hf P ,h ' o / / e i.1'-. -- <":.! Niint. -I. W. M o r s r i \ . l/o-Pioii o f y.if.bi'i;.-- A tti: a Ci. r Zuoli.ui't, W illard H. W . i ,ht. Xntinti'il L'lt-fi - h . i h t u ! -- Ci.ief. r.- anuu-olitsti't Diroetur C aul Vol '. t u n . X otiuhol .!'/ i vir;/ Cunct-f c\, -' ,:. - ~ E \ r c u m e Direetur, Dr. L r n v u , i i lkt-i l s . <irr CONTENTS Vhstraet............ .......................................... - ...............- ...................................... ......................... .............................................. - -- --------------- --------------------- Objectives of the ~tudy........................... .............. ........ ........................................- The working e:.v:ro: m e n t------- . -------- ------------ -------------------- ------------- Method* a; ! :r,'*r'ii:."!its : * *tudy of th e working environ* m*-' t ------- - ............................ - - -------- --------------------------------- The m anufacture ot a-ov'to* r . . . . -- _ --------. ------ PreparaTi. ..................... . _............................................... ....................... C ard in g ...................................... - ................... ........................................ g. 1[: n. ;i-.d . .-.a_____________________ ________ Wev; .g ______. . . -- . . - - .......................................... B r a k e - '* i nan .Uactur*- ................................ ..................................... British m avifact iring method*...... ............................... ............................ . Occupational analysis a n d a description of the chief occupations____ P repatatiott_____ _ . . . . .. . . .................................. ........................ C arding........... .......... . .............................. . . ............................ .. Spinning.............. .. ................................ - - ----- -------- . ---------Spooling, tv.M ing, winding. ai.d treatin g ......... ........ .......... . ............ Cloth and ta p e w eaving__ - - - ______ ___________ ____________ AH o th e r....................................................................................................... Results of the engineering study...... ............................... ...... ...................... N at ir<- of d :-t found in a d . - l . , . r. \tile fa c to rin '.................... ...... C-;:.po-iio;i__ ............. . ..................... ....................... - .......... Partielt- s u e . ................................. ........................................ ........... 1>M e '.eei.tratiou in d itfin -n r......pation*___________________ Pre;ar:vT.oii........ . . . . . . . ___________ ________________ C ard ;:.* ___________ . _________ _______ ________ _ >p::.n:: g ................................................. ............................................ Spoolir v'. twisting. a: d wi:, iirg ......................... .................. ...... Broadcloth w eaving................................................................ ........ Tape, wick, and b ra k t-b a 'd w eating_____ _______ _______ Cord, ror-c. an d braid w orking_____ ________ ________ ____ Brake-band finishing...... ........... ................ ................................. Miscellaneous occupations____ _________________________ Pret ion* d 1st exposure.. ____ . . . ............ ............................. .................... Interpretation of dust counts.............. .......................................................... The c:;tr*-1of a-i-e-tos d u s t......... ............ ........ ................................. .......... Preparation d e p a rtm e n t.__ ________ ________ ________________ Willow'* v ________________ _____________ _______________ ticking_____ ____ __ ______ _____ Carding........................................................ ................ Spooling an d tw isting ................. ............ ................ W eaving....................................................................... Inspection.......................................... .................. .. Summary of th e s tu d y of the working environm ent. (V) Page 3 3 3 4 5 ft Id 11 13 15 lb i IX IX IX 1** Id U* 1*.* Hi l',< 23 25 25 2; >7 07 2X 2!' 30 30 30 31 32 33 33 34 35 35 3fi 37 3X 30 4(i ^ >* ..'.vr.aaii iKaBiii VI 1'ug t Statistical description of em p lo y ee s,................................................................... 45 | Occupational hist ones............................... ................................... .................... 41 : Comparison with other industrial workers................................................... 46 Medical s tu d y ....... .............. ............ ................ ........................... ............................. 4S P rocedure.__ ___________________________ . . __________ __________ 4$ Past medical history....... ............................................. ................................... 49 Symptoms of asbestosis............................................................ ............ .......... SO X -ray findings...................................... 54 Lung-field m arkings................ 54 D iaphragm _____ ____ 61 Physical findings__________________ _________ , . ___ __________ 62 Chest expansion______ _____ _______ ________ _______ _________ 63 Respiratory ra te .................................. -- ......... .................. . ............ 65 Clubbing of fingers and curving of n a ils .......... ................................. 66 H eart defects........................ ............ ........ ............................................ 66 Asi testos corns............ ............. ............ ................ . ............... ........ 6$ Laboratory fin d in g s ......................... . ............... ..................................... 69 A'itestoeis bodies................. .. . . . . ............. .. .. . . . . . . 60 R .-ults of tests on urine............................. ................. . . . . . . .. 73 T he diagnosis of adie-tosis ......................... .................. . __ _ ______ 74 Occupational history.. . .. . . ................... .. ................. 75 X-ray findings.............. ..................... -- ........................................... 75 Cla-.-ifieation of lung-field m a rk in g s ................ .............. .................. 75 Sym ptom .. - ..................... .................... .. .................... ......... .. 77 Reptesenlutive case histories____ ____________ ______ . . ........... . 77 Incidence of a.-bestoH-..... ................................ ........ ....................................... . SO Threshold concentration of a d u s to s d u st................. .............. ........... .... 01 Incidence of adx'stodU in different occupations________ ____ _____ 04 . A-in'.'to'is in G reat Britain and th e United States.. ___ _____ ______ 03 Pathological findings in a -b e sto d ........ ..................................... .......... .............. 96 Gross nppea ranee..................... ............ .......................................................... 96 Microscopic appearance......................... ............................... ....................... 06 Selected autop-'V reports______ ________________________ . . . . . . . . . 101 Acknowledgments_____ ______ ________ _ ________ ________________ 113 Sum m ary'of medical fin d in g s________ ______________________ ________ 116 A nnotated b ib lio g ra p h y ................................. . ............................................. 116 Fyure ILLUSTRATIONS 1. Vacuum cleaner bag arm ' - : *-` 'r r, .IVet h-g -u-ponded lust sample* 4 2. Flow sheet of Amet trun prut v . . . . . . ______ _______________ 3. Mill for crushing sU-stos lib iu__ ______ _______________ __________ 5 6 4. 1 iy oirenvr or wlower ' note exhaust) . . ........................ ............ ............ .. 7 , 5, Exhausted carding m a c h in e s............ ............ ............................... ................ 6 6. Spinning m u le s .._______ _____________________ __________________ 9 7. Twisting m achines........... .............. ................ .................... .............. ............ .. 10 s. Exhausted braider.......... ....................................... ............. . ............. H ; 9, Rope making m achine........... ............................. ........................................... - 12 10. Broadcloth weaving loom............................................... ................ r .............. 12 11. Brake-band weaving loom showing three of the six sections w ith woven band-. . . . . . . . . . . . ... . . . . . . . . . __ . __________ _ 13 12. Row sheet of Briti-h practice____________________________________ 13. Gross appearance of suspended dust collected with vacuum cleaner device fsee fig. 1)____ _____ ___________ _______ __________ ______ 14 21 lg 4.1 4.1 46 48 Is i'.i 0 >4 4 1 2 3 6 1 > ) > ! ( VII figure Page 14. Microscopic appearance of i du~t collected with vacuum cleaner device at 200 ^ ________________________________________ 22 13. Exhausted piling b in s----------------------- ------------------------------------------- 34 10. Exhaust ventilation u>ed for puir.g operations British practice,!------- 33 [7. schematic drawing: of exhau.-t s;.>tem :i=.ed with picker m achine......... 30 15. Vertical exhait-t t e n t n a t h a ; : hv ! . i.,td primary can!:: e m ach in e.* ------------- ------------------------------- ---------- . -------------------- ov 19. Totally enclosed exhau-ted primary -a.-ding m achine_______________ 37 20. Elevation and plan for spoofing exhaust system ................... ................ - - 37 21. Exhausted spooling fra m e........ . - ........... -- ------- ----------------- ----------- 38 22. Exhausted tw :-ting fram e....................................................... ................ ........ 39 23. Exhausted broadcloth loom.................... - --------- ----------------- ------------ - 4" 24. Detait of exhausted loom show;, figure 23............ 41 25. Detail of exaaust u-ed on B rio-'. tv: < : 'm i _______ 41 26. Exhausted Bru-hiug and in-p'-.tl .;. t4. m.......................... 41 27. Form used for recording: occupational :.itory.__________ 43 28. Form used for record,a pa-t a : : tned.ea! 1,story....................- 4`* 29. Percentage of persons, cla-.-it.-d i..y d :st exposure, who had certain di-orders................................................... _...................................................... 52 30. Percentage of persons, classic,-d By in:,-field markings, who had cer tain disorders................................................ .. ........... ................................. 33 t 31. Form used tor recording X-ray find:' 2-. _______ __________ _____ 32. Scheme used in ela--dying X-ray m arkings........................................ -- 54 35 33. Percentage of mal-s, cla--::',-i v ag>*. ad certain lung-field m arkings................ ............................................................ ............................. 56 34. Relation of ground-gins- lung-riel 1 markings to length of em ploym ent. 58 35. Relation of ground-gla-- 1mg-: 1i u.ar-t.ng- to du-t expo-ure----------- 58 36. Incidence f g o ,n n d -u .a-- i : g-:.- i :.._rkit.g- to relation to lei ut*' <i empho.ment and d .--t I - , Tati-.:. ........................... ...................... 39 37. Reiatior, of diaphragm atic rixat. t,, ;-t -xpo-ure. Three stages of diaphragm.-Ou1f i v r h * r- --- i ........... . . . ..................... 6'' 38. Form u-ed f->r recording p u t- d fi h: g s___ _____ ________________ 63 39. P hotom icrographs of a-: -to- s - . - fouml m - p u tu m . Enlarged 530 tin,*'- ,.\e. pt If u:..i h _<rg- : 310 tim e-. A scale ruled . units of 50 micron-. j.;i. i d r ; r . v , be-ide each. a-Be-to-is Body___ 67 39a. Ashe-tos corn on thum b of .Jo-- nr o. 1 man employed 4 years in the c a r l room of an a-oe-t-i- te\-, f.ic'-,ry__ _______ ______________ 70 40. Portions of chest X -ray film- v. h .u -trate the -uccessive changes brought about By long-coat::.u-.j .halation of asliestos d u st--------- 76 41-51. C h est X -ray films U tstrat.ug inept i lual ca-e histories___________ 78-88 32. Photomicrographs of lung sect:,,: s --.owing the presence of nodular fibrosis and em physem a in a -diCotic lung anti diffuse fibrosis and emphysema in an asbe-totic 1tag. A sect.on of a normal lung is shown for comparison. Magi .tication 16 '______________ _______ 98 53. Ashestosis Body in intra-aveole.-dar connective tissue. Practically no fibrosis in this area. Case H-21 Magnification 1,00GX. (Army M edic'I M .-'ii Xo. 52.235 __________________________________ 99 54. \d>c tosi.< Bodies accompanied bv giant cells in an area of fibro-ed lung tissue. Case H -21. Magnification 7 0 5 ( Ar my Medical M u seum Xo. 52,255!--........ ................................ ................................... .......... 100 55. Case H-21. Right lung. Markedly thickened pleura with, fusion of interlobar pleura. D erse fibrous tags over entire surface_________ 102 "JWWWjiM lipw w iaw m gl--u ,y '< B '>,l||ii|i1 '111)1.*'Tr Figure 56. Case H--21. Left lung. Pleura much thickened. Few er fibrous ad hesions than were noted on the right lim a_______________________ 57. Case H-21. Section of right lung. Advanced asbestods. Distended bronchi and air spaces at both apex an d base. Diffuse fibred-- throughout lung sub-tanee and thiekened pleura___ _- ----- 5S. Ca.-e H-21, Section of left lung. Distended V 'v.,m and air spaces at apex. Rather uniformly distributed fibrous am i emphysematous areas throughout re-t of Itmg.............................. ...................................-- 50. Chest X-ray of case H-23, 15 m onths before d e a t h ---------- ------------ 66. Case H-23. Right lung. E ntire pleural surface covered by dense fibrous ta g s........... ...................................................... ........... ......................... 61. Case H-23. Left lung. Very few fine fibrous tags are noted on the pleura............. .............. ................ ............ .................... ........ ................ ........ 62. Ca=e H-23. Section of right lung. Moderately advanced asbestosis. Fibrous area-- and emphysema uniformly distributed throughout the bine -uhstanee........................................................ - .............. ...................... 63. Ca-e H-23. Section of left lung. Shows les. nvohcm ent than right lung...... ................ .......... ................................................... -- ..........- .......... 64. Ca-e H-25. Chet X -ra \-ta k e n 15 months and 1 m onth U;fore death. Part of the difference 1-tween the two roentgenograms is due to a difference in X-ray toci.nhjue___ _________ _____________________ 65. Ca.-e H-25. Section cf right lung. Early a.-l-esto-is. Filiform dis tribution of fibroin* area- throughout lung -u b -tan ee_____________ Page 103 104 105 107 108 109 110 111 113 114 ABSTRACT Ashestosis, a lung disease caused by long-continued inhalation of asbestos dust, was the principal physical defect found on medical examination of .341 men and women employed (or recently employed) in three asbestos textile factories. The primary effect of asbestos dust seems to be initiation of fine, interstitial, pulmonary fibrosis which was not observed to progress ;i> far as the nodular stage. This fibrosis was observed in post-mortem examinations of three former asbestos workers. During life, hum fibrosis can be detected by X-ray examination. The more important symptoms of ashestosis are pro gressive dyspnoea, variable cough which sometimes raises bloodstreaked sputum, and loss of weight. The processes that produce dust in asbestos textile factories were studied ami recommendations for ditst control arc incorporated in this report. Enough dust counts (2421 were made in all {arts'of these factories so that the dust ex posure of each worker can he estimated. The percentage of persons in different occupational trroitps who were affected by ashe-tosi* or any of its symptoms \aried with tin* average dust concentration to which they were subjected and with their length of employment. The only ea-es of ashestosis. three in number, found below 3 million particle's per cubic foot were diauuo'ed as doubtful, well-established cases occurred at limber concentrations. It appears from these data that if asbestos dust concentrations in the air breathed are kept below this limit new cases of ashestosis would not appear. i IX i F r! _[ ----- totoA ln^tmfcgniii 11if-iT A STUDY OF ASBESTOSIS IX THE ASBESTOS TEXTILE 1M USTBY IN i !{O D l ( TION Several important proportion of asbestos have led to its widespread u-e in industry. As even one knuu-, it L iioju-omluntible and an excellent insulator against heat and electricity. Fewer people seem to be aware that its fibers are sulliciently long and flexible to be carded, spun, ami woven like wool. tlax. or cotton. Utilising these properties of asbestos, industries have been developed in this country which employed more than ti.OCti mett and women in slightly more titan ti(i establishments in 1935. Another property of asbestos has been discovered more recently. When ashestos dust L inhaled daily, year in ami year out. a lung disease termed asbestosis may develop. In manv respects asbestosis resembles silico.-i*. but it differ? from silicosis in several important particulars which will he diseased in the medical section of this report. The first record of a case of asbestosis seems to have been math* by Montague Murray in ipnrt. The first complete description of the dhea-e md of the "curious bodies" seen in lung tissue and sputum appeared in 1927 when Cooke i9i and McDonald (22* reported two cases of asbestosis and lifted their rca>on> for believing that a?hest>)>is bodies originate from asbestos libers that reach the lungs. The pub lication of their papers arou-ed general interest in the subject ami numerous papers appeared soon afterward. Hoffman (40) appears to have been the first American to call attention to the magnitude of the asbestosis problem. In 191S he reported that 13 deaths from asbestosis had occurred among asbestos textile workers, and about the same time TVacoast. Miller, and Landis (29) reported on 17 cases of ar-bestosis. Mill's (20) paper was the first pathological report on asbestosis published in the United States, and in the same year. 1930, Lynch and Smith (3S) reported on asbestosis bodies found iti the sputum of asbestos workers. Because several satisfactory literature reviews of asbestosis have appeared in recent years there seems to be no need to present a com plete litti'afure review in this report. Some of the more useful litera ture reviews have been listed in the annotated bibliography. In Merewethers (25) review emphasis is laid on the relation of asbestosis (1 ) 'mm 'nnji^ni yiiwiB-m 7 to working conditions. The eliuieal aspects of the rubfect are ell treated. Gloyne's (10*1 discuss;. at of the pnthc'ogt of asbestosis is particularly helpful. M t d d l e t - 47) .Mi'/.; lectures on paeutno- coniosis contain a section on 'Igtmrt (to) has summarized the lirciatutv report- on 2S farI .,-es of asbestosis. "Active pill- iiioi.ary tuberculosis was ptc-eu: in ti instances of the total 2> cases; the fatal outcome was primarily the result of tuberculosis in 3 instances,'' OBJECTIVES OF TH E STCDT The Public Health Service was requested by the State Board of Health and the Industrial Commission (administrator of the Work men's Compensation Act I of North Carolina to assist them in making an engineering and medical study of health hazards in the asbestos textile industry/ The objectives of this study were threefold: fl t To make a medical study of the effects of long-continued inhalation of ariM>s dust on the human body. '2 ` to identify the manufacturing proi e--es that create dust am! to recommend practices and. lien neees-aty. equipment that will reduce the dust exposure of worker^; and d to tin! out u hat concentration of a-bestos du-t can be tolerated without injury t iiealtli. : I r* < *: "..i - - .: > ; u r r i ' : r j l1'.1 . hVc1-trv:ce . t . *- -dC. .'ifjirir p r .`iNt ( irriv^f ^ y iH I l t 1 r< P tl n lit m at rh at ai <t. di. is At tra as! of I pre nia spo dev 1 int< cott ' )r .HjwwiijHPM'im .................... "ijji'miiBp Bp f THE WORKING ENVIRONMENT M ETH O D S A N D IX ST R l'M E N T S USED IN T H E STUDY OF TH E W ORKING EN V IRO N M EN T The evaluation of the working en\mum.ftir it- relation to the health of workers forms the basis of all field investigutmns conducted by the Division of Industrial Hygiene. The procedure followed by this Division is described hi Public Health Bulletin Xo. 2 L7 (2). Therefore, only a brief discussion of the subject is presented in this report. The study of an occupational dust problem begins with a preliminary survey designed to obtain data on all the occupations iii given plant. It includes the number of workers employed in each occupation and the materials used in each process. The survey also reveals the number of workers exposed to a given hazard. Following the pre liminary survey an evaluation of the occupational environment is made. In the dusty trades this includes a determination of the amount <>fdust present in the air, its composition and particle size and the mea-uremem of the effectiveness of exhaust systems where they are used to control dust hazards*. The latter, in this instance, involved airflow toea-urements of several exhaust -y>tem~ by means of a pitot static tube. The effectiveness of these system- was determined by dust c o u n ts . TH E M A N E f ACTl RE OF ASBESTOS TEXTILES Approximately 00 percent of the asbestos used in these plants is obtained from Canada. The remaining 10 percent comes from Arizona or south Africa, and, infrequently, from Russian and Aus tralian sources. Much of the machinery that is employed for the manufacture of asbestos textiles is identical with the machinery used for the production of cotton and woolen goods. Crude asbestos fiber is sent first to the preparation department am! then, in the order named, to the carding machines, piooimr frames, winding bobbins, twisting machines, pooling names, and finally to the looms and miscellaneous fabricating devices. The four plants investigated in the present study fall naturally into two classifications. Two plants convert crude asbestos and raw cotton into asbestos yam and woven goods, but do not prepare the -! ' (3) nij ijpw BP -MsSi&lkli i ,,"_ ,, fi,'''-.-. -, rrtryilulaiawSi product? for the ultimate consumer. The other two plants purchase hotli asbestos yam and unfinished woven asbestos tape. These. establishments weave brake bands and convert their own woven product, as well a? purohu-ed material, into finished ro o d s . The practices followed in tie1plant- studied are seliematieally presented in the flow sheet shown in figure 2. PREPARATION CN; ^ Cnoth itiff.--The first ) step in the manufae( ture of asbestos textiles is the crushing of the crude stock in a ruffl ing machine. This is accomplished by large \ iron roller- whicb re voice in a steel pan in which the crude ma terial is placed, >See fig. o .! Thi-operation se p a r-at es 11ie filler- and loosens the impur ities that survived the cobbing of the ore at the mines. The mi>h- . X "' UKoperation docs not produce much dust, the fillers being disin tegrated by a ma-hiiu: L and twisting action. Most crude ore mu-t be c ru s h e d fo r 2*' minutes, although in some eases it may be A satisfactorily disinte grated in 5 minutes.*1 irniWiirfMru FiGLRE ` ACl t-M C LEAN ER B a g ARRANGEM ENT FO R COLLECT* .G SoSPEN D ED D U ST'SA M PLE S. The crushed asbestos has a matted appear ance. Following the crushing, the asbestos is replaced by hand in the bags for delivery t" the willowor. 11 eg. --The widowing or opening of the asbestos is essentially a cleaning operation. The widower beats and shreds the matte! so; out pre (eHiMMM M M lH a ' S~w T Srsxer, or Cp-enar j FLOW SHEET A M ERICA N PRA CTICE In a* Asbestos Srissar WiifsweP (incistcartae*enpinrtgB)Ary ---------------a_ Passing --- . 1 7 _:ra*a s *tiaeo T t1 Same piar,sa i s [ sot aspIs; $:- | oodary ssreen-rg ' * Passing Ma'.ifUl occasionally areeoes ^g*m to re- :s*er fibra test nsy !oc ised in low grad proiasts - otseraisa fijcieiat----- Serial Tollartad Fly i-l^ e r (lA sluirg screes* *a Ratamad Passing ^ Cottoa a ? ..i to aU for peint it low gras saaant product f'r s. orris vC-^r:; vc.-.r.~ V Frmary F-iaar I;.:.-i* s ^is-t-rn c: Oilf --- la.otstry . It p, **."5 t . . or.e I. sa*. passes t ir .- g -t ;< tinaS.f f ------ S--te i sti;* t_* -- ^ -*---- .~r-- a Sov _Cg -p*:!*; :a r i roving f fyiPAing fr iz e s trine a n *ul* p irn i 5- rearing p'*--tb r WA*.*..*aJi ^goe- e - ) ' spooling eros t-te er-eccw 7i*tisg cf she$e spars- tis-jt **T'a*p<54-a Tape, wis*ani brace lining, ' <eti*T-j .aspattuii f e li as yam * ?.ci*Tery Screen raising -LaforpgraeclsiynsignsgiaJ,/ ; liras fir.--s S ill to Svili to p ain t S'v.iiacturers efaori thpaepre*r a u u - Spolalantsby*sIavn.e- oat fjrtner processing Cadeaaerea Treataaat Urprgrtioa with eith er rwgetabl# rcoenspionusB,if'or' *?n*, * Karvast Finitshed t,Includes calendering , grinding, w illin g sad stencilling} ttarkefc F ig u r e 2 .--Flo w S h e e t o f A m erican p r a c t ic e asbestos masses into individual fibers and removes some of the rock. The asbestos fibers that are retained are delivered directly to a storage bin or conveyed to one by pneumatic duet, (See fig. 4.) The ma terial falling to tbe floor is screened in order to separate the grit from the short fibers. The grit is sold to cement manufacturers amt the short a-bestos fibers to paint, paper, and roofing manufacturers. The willower is fed manually by a laborer who lifts the crushed asbestos into the willower hopper by means of a pitchfork. The beating and combing action which takes place within the machine produces a lurge amount of dust which escapes from the !w-i-uutig enclosure. The production of dust is increased when waste asbestos, recovered from the cyclone separators which form a part of the dust- removal system, is willowed for reclaiming purposes. This latter operation i- called fly willowin^. At one of the plant? ~tudi*d. the willowed asbestos i- passed over a vibrating screen. This operation insures a cleaner product, since additional grit and short libers are removed. Where a second screen is not available tbe asbestos, may be passed through the willower a second time, a practice which is followed at two of the plants studied. The screening of asbestos is a decidedly dusty operation. .Wring.--The asbestos fibers consist of blends of various grades and often include a certain amount of waste recovered by the fly willower. This process is followed in order to obtain end products with the char acteristics demanded by the market. When a batch of asbestos has been made, it is then mixed with cotton. Asbestos fibers must be mixed with cotton before they can be spun and woven. The amount H ... i of cotton used depends upon the quality of the willowed asbestos fibers used. As a rule, from 5 to 15 percent by weight of all the asbes tos textiles produced in this country is cotton. Piling.--At the plants studied, the mixing is accomplished in two steps, the first consisting of placing the cotton and asbestos in alter nate layers in a pile upon the floor, and the second step of feeding the mixture into a picker machine. The batch making, or the placing of the cotton and asbestos, is known as piling. It is productive of much dust since it i* necessary to spread out both the cotton and asbestos into uniform layers, which involves the use of a rake and much trampling of the materials. Picking.--After the mixture is made, it is lifted into the breasthigh hopper of the picker machine. The material emptied into the l f: ! ' t t t '-S', ; /' ` F i g u r e a . - - F l y o p e n e r o r W il l o v v e r N o t e E x h a u s t ). hopper displaces air in the hopper whieh causes dust and fibers to escape upward into the face of the worker. In addition, the cylinder and accessory rollers of the picker machine operate at a high speed and much fine material escapes from the many small openings in the frame. The dust that is fanned out of the machine, together with that produced in the feeding operation, makes the pickernnm's occu pation comparatively dusty. In some plants two pickers are oper ated in series and in others only one, through which the material may be passed several times In either case the picker discharges directly or by pnettmati. duct into a collector bin. Where only one machine is i'-.d'.-tdo, however, tiie pickerman must move the material by piUufork from the collector bin to the (loor of the picker room for its recirculation through the picker. At one of the plants studied there re two pickers operated in series and connected by pneumatic 43163--as--- a w ww.ii'- mm duct?. Here the collector bin i? also the topitre bin. In order to prevent rh- mixed material from aerumulatim: in a >twp pile a man i? 'tatinii. i in the stock bin at all times. This occupation creates considerable dust, since the eott<>u-asheslos mixture is delivered into the bin by overhead duct discharge. In order to reduce the dust exp"-ure of the stock-biu man. his position is made interchangeable with the piekermati, each of whom spends a half of every day in the stock bin and a half day at the picker. In the plant having only one picker, the mixture is trucked from the collector bin to the storage bin. At one of die plants studied, exhaust ventilation is provided for the picker ma- hines and the mixed stock storage bins. Oil sprays are F .G w R S ; - E x S A C S * S C a RD 'N G M a CH NS. i r e o \.-::dy n~ed within the [lickinc machines in an attempt to prevent ilie n>:mati'*n of dust. C A P.D tX G Ftoni the storage bins the ?t<>, . - it i otiied. is baud-irak'-d to the cardingpnachiue? where it may bopled upon the Horn* m jI into d.t .ntier nt ihi- bi'eaki r card. f The cards perform several duties. They give the fillers an addi- tu.- ..;i.:t_e hem in parjiel positions, and form them into ro\i- T.-- tena rovi: ^ is applied to the strands of parallel fibers " ' .......... . A ; rdiru: m !* con-dst' of two almost identical nan i.u.es. Tin* one through which the cotton-asbestos mixture passes fir-t i- termed the breaker card, and the other, the finishing card. The two machines are quite similar iu that a large revolving cylinder with several accessory rollers performs the major portion of the work. (.See fig. 5.) The carding operation is quite similar to that of the 9 rder to a man creates ul into e dust goa hie in the iiy one go bin. >r the v- are -ne picker, the essential difference being that the roller and cylinder sur faces are studded with fine steel bristles rather than large hooks. Some of the rolb-r- r.-:- - :_r out the tangles, while others doff, or remove, them tivm the eonmmg rollers and the cylinder. Aside from t|ic*e main featurns tl* two units differ t!v. The breaker card i- tapiippci with a mooing it**pior -iauiaf ; that used on the picking machine wIdle the fni-hing <*-.-*t.; i- pmvi.i* c wifh a device for forming the carded iihefs into trand*. In the ; heps studied a -y-tetu of eonveyor lattices transfer the curded libers jrotu one nun lo'i.e to the other, The out-ide strands of roving are returned 14 ~ " '*'*** - - i - --1 --- -* -- I t -i 4* i i : I FiGLPS ~ 5 P I\-,C ,G `.'-ess to the picker for reworking. The remainder of the roving is wound O il long rollers with llanged end-, called jack -[....!-. vent The bristle-studded cylinder- of the carding machines revolve ;,t high speeds and much lint i- thrown into the atum-phere. The effect produced hy the revolving cylinders and wheels i- similar to that of a fan. and as a result much of the dust remaining on the stock at this d to point, as well as asbestos and cotton filters, is blown into the air. All into carding machines studied were provided with exhaust ventilation. While practically all of the roving is spun into yarn, some of it is nidi- marketed without further processing other than winding on spools ,,r into into coils. In this form it is med for electrical insulation and for hers conversion into packing for machine bearings. deal I'-es O'IN N IK G The with The jack spools containing the roving may be conveyed either to ff.e muhf spinning machines shown in figure u nr to the ring spinning ork. the frames. The spinning, on whatever machine performed, is a twisting operation which imparts strength to the strand of fibers by inter- w ''iiiB f "'U11m ihii ' ' M W W P t t 10 locking or meshing them together. The ring spinner twists the roving as it is wound on a spindle, while the nude spinner performs the same treatment in two operations: first, spinning it in 5- or ti-foot lengths and then winding it on a spindle. The ring spinner makes a yarn that is- stronger and hotter in many respects than that produced on the mule spinner. W INDING, TW ISTING. AND SPOOLING The spun yarn is converted into stronger thread in two operations. It is taken first to the winding machines where it is transferred from spindles to tubes. After being wound on tubes, the yam goes to the twisting machines where the thread from two or more tubes is brought together and twisted into one thread. In the twisting operation the thread is frequently strengthened with lira's, zinc, or copper wire, or pflyy* s - - 'i urp'in'w--s tqr . ~ , i / A/' L F i g u r e 7 - 7 .-, , 5 - 3 V a c h i ' . E . with cotton twine. Following the initial twistimr operation the yarn may return to the winders for placing on special tubes, in which form it is marketed. Then again, it may be conveyed to the cop or twill winders where it is wound into spindles for use in the shuttles of the looms. There are a variety ..j w;;., _* op.-rati'nms that prepare the yarn in some particular manner for the market o r for use on certain types of machines. Likewise, there are a variety of twisting and spooling o p eratio n s, ."i-eiig. 7 The winding and twisting of th<- is .bowed hy a number of more or less related operations. The thread may be converted into cloth, tape, wick, brake lining, tubes, braids, or formed into rope. >ee tigs, s and P.,i A >mall amount of the product of the winders and twisters is treated by passing through a sizing compound, and subsequently dried on reels before being wound again on tubes for the market. ng me (hs lat :be ns. ora the xht the , or I J .urn 01711 twill the the tain ami >r of into ope. tilers and r the 11 WEAVING The weaving of asbestos is done on looms that operate in the con ventional manner. Both cloth looms and tape looms are used. See tigs. 10 and 11.) On the latter, brake lining, asbestos tape, and wick for oil stoves are woven. The tape looms dilfer from the cloth looms in that the warp is segregated into several strips of material and in that there is a dint tie P r ea< h -trip of warp. The weaving of all strips proceeds dnui!t.-meoi-!v; o v ::: >hani-m operates all shuttles and a single reed suiiires f<>r r all warps. L o o m s i for tape weaving are made in multiples of ~ 0 spares up to as many as ;pi, Both dry and wet weaving are employed for the production of both . cloth and tape. In wet wea vino t It*wa t p is pa-sed through a shallow pan of water and tile eup for mein the shuttle is dipped, into water. Dry we avino ,,f broadcloth ptodu'v- ' much lint mid d u 't. The t h r e a d ' of th e warp are continually rutilu'ii v.-i-t eaeli other as tin1v ate moved from positions i1 above or below the line of the shuttle * which is shot from one side of the loom F ig u r e 8 - E x h a u s t e d B r a -c s s to the other at each change in position of the warp. Filter payments are rubbed from the threads at each change in their po-ition and the fanning of the air by the moving machinery carries them into the atmosphere in and about the loom. The same machines are used for both wet and dry weaving. In the manufacture of a-hestos woven products at some of the plants studied, the warp i- formed on individual looms by harnessing the thread from many spools which are hung on creel racks. At others t mmpmiMBWi 12 the warp is first wound on a beam from the individual spool*and then transferred to the looms. The latter praetiee makes a more compact weaving unit as creel racks occupy several times as much floor space as the loom. The creel racks are attended by a worker who is kept S '* * f ~ ' | *' * *#y~- f 'f T | i F ig u r e 9 - R o p e -M a k in g M a c h in e i 1 busy tying broken threads ami replacing empty -pen]- with full o n e s. The occupation involves an expo.-ure to a-be-to- (iust for which the looms are largely responsible. The asbestos cloth is usually shipped to firms that convert it into gaskets, fireproof clothing, and other products that require a non- 1 combustible fabric. Some asbestos wick is packed for the market without further treatment. Asbestos tape is usually sold to other industries. Some plants that weave brake bands sell it as a crude woven ribbon of fabric to finishing factories, while other manufac turers of the material convert it into finished products. i B RA K E-BAN D .MANUFACTURE The manufacture of brake bands proceeds in several steps, the first being the impregnation of the woven fabric with either an as phaltic compound or a vegetable resin. The latter is the newer form of treatment and is rapidly supplanting the former. Following this operation a heat treatment is applied in a specially constructed oven. In practice the ribbon of woven asbestos passes first into a vat of the ipum w mmm u treating substances and thence immediately into a baking oven. These operations are earned on in a building tiiat is well ventilated and which H removed from other structures sufficiently to reduce the fire hazard. The treated asbestos fabric is now calendered into uniform width and thickne~< and one surface i- ground smooth. The brake-hand material is next cut into suitable lengths and holes drilled into them according to pattern. Finally, the finished brake bands are branded and packed for the market. In motile plants molded brake hand' are made of asbestos vara ami B ritish ? ra:tic e lCapital litte r s is denote processes th at ere cat in use in the American p la n ts in volved in th is study.) FLOW SHEET Crude A sb e sto s Cra*sher l MIXER * MAGNETIC se p a r a t o r i SHAKES SCREENS (ROTAR* THREE COJtPARTMBC SCREENS) FEEDER BOX Paw c o tto n cleaned i n opener and p ick er - converted into a r o ll o f f e l t known e s "la p s " rericen practice j ro tto n added a t I tn is p o in t followed jj>y P ic k e r nixing fillo w er tBRITISH EMPIO* VERTICAL KILUWER KNOWN AS A CREIGHTON OPENER) S creen in g (SIEVING - BRITISH TEKMINOLQGI) _________ * S to c k B ina Carding Machines 1 R ovin g FiG JR E ` 2 1 R em ainder o f flo w sh eet sim ila r to t h a t f o r A m erican p ra ctice. F lc S h e e t OF B r it is h PRACTICE, a 'Vii!u>'i;c i."ii; Tl.c :t>cc" '*:i-i-1~ >! pacing asbestos thread tliiT. iuu ;i liaii ni tc'iiac;' material and immediately winding it upon a spool or cylinder. Enough of the resin will adhere to the asbestos to form a matrix into which the asbestos thread will be imbedded. When the desired thickness is obtained, the spool or cylinder is given a heat treatment which hardens the resin. Tiie baked cylinder of material is removed from the spool and cut into narrow sections. The circular bands thus formed are ground, machined, and otherwise made ready for the market. 1 dus the F Tin fact tini i tio n l! Fui has Ann q>m A quit of p tea. whe on i elirn The opei the i is >L nper prue knov Tl cotte niLxii asbi`the 1 carili piiki mate formi En lattic The i near accor Vvhei medi The grinding or surfacing of the brake band* produces considerable dust. In tlie plants studied exhaust ventilation was used to control the exposure. B R ITIS H M A M K U T I RIN; M ETHODS British practice differs in many respects from American practice. The same type of machinery is used in both countries but in British factories, dust-control equipment seem? to be more generally used than in American factories. British factories specialize in the produc tion of fine yarn and this involves numerous difference? in practice. In England the processing of the asbestos begins, as it does in the United States, with' the crushing of the ore. hut when this operation has been complete! the manufacturing process does not parallel American practice until the fiber lias been carded and is ready for spinning into yarn. (See fig. 12.) After crushing, various grade* of asbestos are blended in a machine quite similar to the conventional type of mtarv concrete mixer. It is of passing interest to note that the same device is used for blending tea. The blend of asbestos is passed through a magnetic separator where certain mineral impurities are removed. It is cleaned further on rotary shaker screens where some grit and fiber fragments are eliminated. After screening, the material i- fed into a willower. The British employ a vertical willower that is known as a Creighton opener. Its action is similar to that of the American willower, and the internal revolving inoohani-m i- retained. The willow ed material is subjected to a final cleaning on a second -ft of screens; such an operation is termed sieving." Widowing is the la-t of the cleaning processes, after which the ashe*to* 1- placed into bins and U thereafter known o* stock. It is now fully prepared for carding. The practice at the plants included in this investigation is to add cotton to the asbestos and then subject the combination to a thorough mixing in a picker machine. In England cotton i* added to tiie asbestos on the carding machine, both fibers being fed separately into the breaker card. The cotton in all probability is prepared for the carding operation on a conventional type of combination cotton textile picker machine which opens the fibers, cleans them, and form* the material into laps. The latter term is applied to the cotton which is formed into a broad ribbon of felt and then wound into a roll. English carding machine* are equipped with a feeding conveyor, or lattice, upon which first the asbestos and then the cotton are placed. The asbestos i* .deed from a weighing box that is suppo; red over and near- the .inside end of the conveyor. This box feeds asbestos in accordance with a predetermined ratio of the fiber to the cotton. When a certain weight of asbestos has accumulated in the box. a mechanism opens the bottom and allows the material to fall upon the miw itmmm 1G lattice. Further along a roll of cotton felt rests upon the lattice and unwinds as the conveyor moves forward. Thus, asbestos covered with a layer of cotton felt is fed into the first machine of the carding unit. The carding operation has already been described. The roving produced by the carding machines may he converted into yarn on either one of the two machines, both of which have been discussed. As was pointed out. the ring spinning machine produces a much finer yarn than the mule spinning device. Since the British specialize in fine yarn, the ring spinning frames are used virtually to the exclusion of the mule spinner. The preparation of yarn for the market and its conversion into woven products will not be discussed since they are similar to the processes used in this country. OCCUPATIONAL ANALYSIS AND A DESCRIPTIO N O F T H E CHIEF OCCCPATIONS The occupational analysis of the four asbestos plants covered in'the present investigation is shown in tuble 1. T a b le 1.-- Ore . "p c ' analjsig o f uorken in tic aibestw textile manufacturing lfl'1 <*tr-i '3 'in s s-t :-y P i-t A M ft! ark- r? n- P'r-m* B it Pl.ra! C M Haut D M Total M Pre;'ir .' r.' F'-rv:' en..................... <\\ A-P-f.te.r.................................... t .......................... C riLc F rw.-r.... ,,. . , ........... ..... / To:.:........... - a v h 3]HUiG, Hglfttri. ..................... T caA ...................... -- . spooling: Spoolers................... TwiFsti`<nrc.*fnc^a.... ........... ,TU-ewc-**j>:r*.te;-r.ts....A....a..,'..ii...........................................- t - ; ....................... 4 Zi j:iii 13 4. 3o i" ^ f|yiB^ipppw'w'lti"jj' m m m t ittice and ered with ling unit. converted nive been roduces a ie Briti'h rtuallv to -n for the discussed NATION'S red in the 'ni'/acfuritig Total MF 2 ,,14 . . . . . W. 11 4'i . . . 43 307 ' .sa m ihpif y iTtnr'iflfftilf*-H*"** -- trihtS* T a b l e 1.-- Occupational analysis of workers in the asbestos textile manufacturing industry-- Continued Seeti'in are! arte. ;:y Pi : A M N'umtvr nt workers 1 Fiant n Plant C At M T .'il M tpvt-irnv.'nlm.cni........... Yarn pin-kirs. s3 T o r ., ! ...................... Treating: T reaters.......... ri ; - -- ----- 1 ...................................... Clyth a t i\ .na F 'W ien............ -fte,air.eUr.1.i.s.....h.......-..... l, i> t. >r>r-.......... CH'>re[e1Wbwri*:-n.-.i.e.r.--'........-..- 11 23 2 Total. Tir# aii`i tr-j.ko-b.in-1wetvia*F*^renivu ................. ttVivn1* r {*.............. rHV.rivf^irr-r^ri-T..i.k....*.....1....i....v....i............ OIt*rK.......................... T*rU* 1>1V 2 Cori r.;^. ; l*r .. 1 rke*r- Fin'-U..r_ Trvri-r' i -lr.y r'__ iBrurr:rt:r;r*e:-Irfer'rii.r.,. irri> r'___ Counts.. . . ............... T-r*; ........ tl !ir**r ELr*it_:-\tevvtr- .. ...... VVVatrrlt'rh.,cr.n**.er...i.e..r..k...s...... ........ .......... T nl. $ .......... u Offtw *nh*r>............... i .......... j .......... \ s T o ta l ........... l" . . 11 GraaT to tal.. U" > 223 14 ... - ................ r "i" " ^ ............ ... 11 ............... -- -- r- 24 .. j 'ji..:-- .... =w_ Cl - 3 ...... 1:1 - . .. i :i .. i ............. . "i ..... : ... I . ........ ...................... 1 4 .. .... > , .i .1 14 ri 23 1 ... i 2 .. 22 i i ... . 2> J1 1 1 ri h 1*1 Reference to table 1 shows that a number of men have been listed as foremen and second hands. These terms have been adopted from the cotton textile industry. They do not always mean fullime supervisory duties, as might be presumed tin most cases foremen nd second hands are engaged in all the activities of the department to which they are assigned. Further mention of these occupations is not made in the brief occupational descriptions which follow. IS prepa ra tio n Cruthtrintn em pty the raw asbestos. contained in 100-pound bap#, into the pan of th e crusher. They also operate the crusher and remove th e asbestos fiber after crushing. Willcu ers or optners handle crushed fiber ami waste roving. The crushed ore is fed into the widowing machine by means of pitchforks. T he willowed material is usually blown into a -peeial bin. The waste accum ulated by the machine is removed several time# daily by the widower. Willowers also operate screens for separating coarse granular m aterial cob- from th e fiber. P ifk tn u tn make up the a -b.;-t,.s-cotton batches piling according to specifica tions and pitch the material into the feeder hopper and the picker machine. The pickennen in -oine p.a: t- may hand truck to peeial bins the m aterial which is blown from the machines. CARDING C,irtltrs operate the car il- g machine# and clean them when necessary. Storkoun handle the -:-wk prepared by the pickermen. The m aterial is con veyed by hand trucks from the stock bins to the card feeders. Tn.-. r* lo., k after tic -t. <-s feeder- and ruling jack spools. T he latter are removed when full, ami p placed with em pty jack spools. The occupations of tender ami carder are in ..me plant interchangeable, SPINNING M u l t .pint.-r. o p e r a t e e mule -pinning frame-'. Rino pinn- r- operate r:r z -t ii.i.ii.g machines. Hiiptrs 'bobbin boy- s--i-t ti e mule spinners and ring spinners conveying full jack spool# of roving to the -pinners and carrying em pty spools back to the cards. They ai-o tra:.-; - r tne -pun yarn and attend to th e roving jacks and bobbins whenever rruuired. SPO O LIN G. TW I-TINC,, W INDING, AND TREATING Sp-n-lrrs tend the poolirg machines and handle spools on which th e spun yam is wound. T.' rs d>o/ ltlj.tr - i. r-r a te machine# that t wi-t spun m aterial into heavier and stronger yarn. li'ifWcrs operate \a r : w lr.il- ^ :...whine-. Trm tfr pa- yarn th r.-.g h so c ia l conipounds ''usually predom inantly starch) and wmil it large reel4 f r <ir> 1: z. In brake lining m anufacture, treaters handle a-phalt and re-iron- material- with which the product is impregnated. Ynm pachrr* wrap and 1 finished yarn. CLOTH AND TAPE WEAVING '' ' t ,1 - Brtitt'hlotf. ifiv ir * operate both dry and wet w ealing looms. Tape iretutr* operate loom# for weaving tape and brake lining materials, lnp>tc!ort> irn-l m .'o e io o . inspect and examine all woven m aterial for defects and pass tarn: and brake band- through calendering machines to achieve desired width and thickness. Crtdtr attend to the creel racks on which the warp thread spools are mounted. Cop u-in<hr operate cop-winding machines which wind th read on inetal spindles for use in the loom shuttles. H earer htlp- ri u- tally attend to the drying of broadcloth which has been woven wet. They al-o handle material for the creelers and weavers. TOW WB-- Wls- v 'Hf-wwnaw]Wj.'ULIM'WMWMHMPWaWWMIl.llUBIJ.I,v*** 19 ALL O THEIi Cord, rope, and wick worker* operate special cord and rope-making machines and braiding m achines Brake-tininij ti^isl.ert include treaters and dryer men, calcnderers who operate calendering machines for squaring uneven edges, grinders who smooth off uneven surfaces, and cutters and drillers who cut the finished band to required sizes and drill it for riveting to brake h o e- fo r automobiles and other machines, In the plants studied, these occupations were interchangeable. fi'enernl labor includes tho-e occupations a-'oeiated with maintenance of equip ment and generation of steam. They also include janitors, watchmen, and shipping clerks. Superintendence is concerned w ith t: e supervision of all plant activities. RESULTS OF TH E ENGINEERING S T l DT D C -T sTCD IES In the present study, dust counts were made by the impinger method t2 J, using ethyl ah-ohot and distilled water mixtures containing from 25- to 50-percent alcohol as a collecting fluid. Two sampling methods were used for collectimr du-t for chemical analysis, til Settled dust samples were collected at the breathing level and 2 >airsuspeuded dust tva< collected with a small, hand-type, vacuum cleaner fitted with a removable, paper-ha^ type filter. The latter method is similar to a procedure developed by Hateh (5,). iSee fig. 1. In addition to chemical analyses, petrographic analyses wete made on several samples. In order to determine the particle size of a>bestos dust, an Owens jet apparatus was employed 2). The samples col lected were measured by means of a filar micrometer at a magnification of approximately 1.non diameters oil immersion!. Photomicro_-raphs were also made of dust o b t a i n e d by the vacuum-cleaner device de scribed above. X .V rrR E O F TH E I> r-T F o r NO IN a -H F .'T o - T E X T IL E F A C T O .' (i}iv[iositi<>i`.--Table 2 shows the results of ehemical aiialy-is of settled dust samples obtained by the Hatch method <">'. Examination of these tables does not reveal significant differences among the various samples^ It will be noted, with one or two exceptions, that the total ash (no water of crystallization present i does not vary greatly. The value of 54.5 obtained for wet weaving .sample b) is due to the moisture content of the dust sample. Calculations of composition on an ash basis bring the values into closer agreement than indicated in either table. The results given for sample 11 in table 2 are for brake lining which has been impregnated with resinous compounds. 1 C anadian asbestos (eryst'tile'. the as^e-st'* use-1 in these factories h js the following Ash, S.x7i: S&;, 10 49; K:Oj, 1.27' 47 41 FV:< , j ,v, percent. (Asbestos- Vol. 2, No. 7. Jan u ary 1922.) mrnj" vemqmt*p tf**r*' - --.WBffBa 20 T able 2.-- ti>nncol of Htthd dust samples obtained in asbestos textile plants rh^-w-trest n wnxh sanij'if? were Average chemical cnmp itioo of sample? iyercem;we` " 1 11 '' Ah ?1U: R;Oi CaO MCO Fe.O; Remark? }'* , . ... x !**. ! ii . ii \ ........ C .-::j ... n "2 r ..iiiT t, cl7 H -4 **2. ** 3 T'd *' o- 3 >1.2 34 1 30.5 J7.1 13 5 It S 0,3 Hi , A. W* \\. . XV* </ -2 . A ....... . -- }T\, . '1 s i ?. . :x 3 l-` x\ - "2 i , H ....... 72 * ii. Hr : _ 23. 2 ,v\ 0 '4 .*>*y* 32. n 4r, 2 In 9 5s 1n0 o $ 6.1 12 D'l-* '* (xi! >i. > 34 7 15 2 l` 7 35, S 3 34.7 1- "Ji 34-0 33.7 .5 34 5 V 32.3 l.tt 34.0 2 21.5 > 30. 4 1.0 2* 3 * i 44. 2 .6 31-2 10.2 N%ar willftirer10.3 Ti.-i*<*icard b<**d? fi.y lie. 6 k Bonom of cards. U.2 AT T; w^avinir loots. 4 * W. *wrvav:iur. 7. > B' *ar*'.`Q 4Ta*S-?, 7 7 O n I-Jhjtt*. Oov-ri.'iMtTbraoa*cJiokBm2rti..i2 sepmuted 10 6 3-Ef-t ijr cart! ronta dust. T \ bi.i: <''! a rf{l;s*s u f /,`ti d dust s a w p its e o lb e u d if* an asbestos tfli,}* plant i>- Xi'r- lr: K ' A w t ^ k cl.etU ""tl rw : ; inn of fiiiuiiles ..t- A.-L H JJ r M iO Ff-.U: Retioarki , i i Vv " *. 7' ?'-* S +. 7 ' * \j .... * `4 v' ., ,j >' 7 o' v. . 7 4 7 o- Id \ '4 , SU V7 ll< 4 12 i> K > o 34. V I <j 3b. n .it 3 > "1 . . 4 34 3 `t .0 4 . *1 32 1 u 3 i r, 7 IV o f, ^ <t. n-r ii utr t. 3 1 *- : i B* ttvw r. iT iiu .e 7 11 V - r ' , m.ioh. 7.tl H r ;*. loth K v.-w sc. o 7 Lo. - 3 r TTLic^m's. *4 7 \ ( ,* - : < , ^ n*s. c. N vt .n n ^ -rh im 4-. C .-~ Th<- lo--c- on iirnitimi of all samples analyzed are due to the presence of cotton {her and im>i~ture. Tlie 30.5 percent loss on ignition of -tut J1 in tabic ! i- probably due to the presence of cotton fiber?. in pushing, it may be pointed out tlutt no carbonate of the order reported by Hurlibut and William? was found in any of the samples analyzed (0 >. No quartz was found in any of the samples examined petrograplii- eally. The consistency of the results indicated in tables 2 and 3 is more remarkable when the physical characteristics of the dusts are taken m t. i -e,. d e r a t i o n . Figure 13 illustrates the gross appearance of the n w r h r h e v a c u u m c l e a n e r device above mentioned. K a o n - . m i p . e -iH 'H n m t h e rigure r e p r e s e n t s two grams of dust. There a ie c . - d n b u v m v - a m o n g t i c - a m p l e - , b o t h i n color and bulk. Preparation and carding produce granular material. Weaving l (pPfWT- % TW ISTIN G iv RING SPINNING' ii MULE SPINNING ti WINDING If SPOOLING <i I, I ; CARDING tl i PREPARATION ** ; DRY i WEAVING WET WEAVING f. - " V " V, /n : `* F ig u r e 13. G r o s s Ap p e a r a n c e o f S u s p e n d e d D u s ? c o l l .c c t e d w i t h v a c u u m C l e a n e r D e v ic e . (S e e f i g u r e 1.) ufiter'.rt*> w M M iifei 22 samples, on the other hand, are bulky, the difference probablv h,,Hl due to the presence of long asbestos and cotton fibers in these samp!,-. Carding and preparation samples contain cobs which are present i the raw asbestos. The darker appearance of the samples shown in t|, top row of figure 13 is difficult to explain. It is probably due to i|, " - -V SM V P R E P A R A T IO N CARDING L. : ..ij MULE SPINNING ' ** RING SPINNING IH \ A SPOOLING -' At . . WINDING ** *. " i '- ' ,_ 1 . ,K T W ISTIN G -i : r* V\* ' <. . - 9 , ' . , * ^' t,, * - *. * - ' 't , ' . F D 5 '' * t - v "v G - # a "' " i V' .\ r < : " "a <. ^ I X ' ' . ; / W T WEAVING f ig u r e i 4 . --m ic r o s c o p ic a p p e a r a n c e o f S u s p e n d e d D o s t c o l l e c t e d w it h Va c u u m C l e a n e r d e v ic e . 20OX. contact of the spun asbestos-cotton mixture with oily metal surfaces The microM'iijiic appearance of the vacuum cleaner samples n illustrated in figure 14. The presence of both cotton and asbestos fibers and of small particulate matter is readily noted. The dust iron tbe carding loom is most striking. It has few fibers and it Inn considerable particulate matter. 23 >eing pie*. u in i the >the .1 1 Ai 1 Particle size.--The measurement of dust particles suspended in the 1 air of asbestos textile plants is difficult because of the presence of | botli asbestos ami cotton fibers. The differentiation of these fibers , under the microscope is not always posable, especially when the j fibers are short and fine. Several samples obtained with the Owens jet apparatus were examined with a petrographic microscope in order * to estimate the proportion of asbestos and cotton fibers, but no satis factory teclmicjue could be developed for this purpose. In this study, particle size determinations based on Owens jet samples were made by three methods; (1 >euseope projection device; ri) a filar micrometer attachment to a microscope (using oil immersion, 1.000X), and (3) by means of photomicrographs. I Data obtained with the euseope showing the percentage of fibers (irrespective of whether they are cotton or asbestos) are presented in table 4. These are based on Owens samples and not on impinger samples. With regard to the selectivity of the device used, little information can be given, although it is known that for discrete particles, the selectivity of the Owens apparatus and the impinger are the same (2). T able 4.-- [frla!ion of fibers to pqrticUs in various ( h w n * j it samples i A ctiv ity XuKmlfUur-sr of NP'miririN{{rof Tut ii o*unt P< ro-nt I 1 4 ttVavine :...................... ................. Weaving __ __ , ................. Fickju".......................................... Cir-I n n . ................. . ................... 22 it 14 Cru-tiios ....................................... *i f PI m i B * Plant A. The results given in table 4 indicate that weavers are exposed to s the highest percentage of fibers. This is to he expected heeaiire the warp threads fray as the shuttle crosses them. Samples collected near the pickers and carders have fewer fibers, while the dusts to % which erushennen are exposed have the least proportion of fibers. The relatively low percentage of fibers in suspended dust explains the small number of fibers observed while making dust counts of ITH impinger samples. The latter were usually diluted to give 20 to 30 particles per quarter field. Hence, except for weaver s samples in ces. which considerable fibers were observed, fibers an only rarely found in making counts of other samples. (Dust counts included both >tos fibrous and nonfibrous particles, irrespective of size.) O Ill Table o illustrates the size range of particulate matter. Two luis hundred particles in each sample have been measured by means of the 43162--as------a Mf-'n w a M m U if tw r i,viw1i> w rtyi,llr i''il(iii'i 24 filar micrometer. As may be seen, the median size varies from 1,22 microns to twice this value, Fulton and his coworkers used .in electrostatic precipitator to collect dust samples and calculated an average value for the total distribution of fibrous and nonfihrous nf 1.33 microns (4). The median size for particles less than 5 microns, as deduced from data given by these investigators, is approximately 0.47 microns, which is much lower than the values given in table 5 of this report. This difference can probably be attributed largely to the type of sampling devices used in the two investigations. T a b l e 5.-- Size frequency distribution o f particulate dust suspended in the air of textile plants 'on.; 1 u ts I *h< n I 'r* {' \Ti! 'on t ' Mb, ' V imhj 'l it i . \ \. i1 : t>rv n!t b4l U ,MTu -Ul*' r;,,,,. JVret'niajK* frt^u* 'minynoiifctm<n-Mh punicJe*iic group m icron' <}\ i-t- it 0 ` 1 1 c. J 3 X.> 4 4 5 =1 ".'It to in fn It> Hi In Hi ! in 1. or Total 0 V* 1 4'.t 1 '.fl* Hf J 3 4't J ',,<>4 4t* 4 w ii:ur* 1 1T 1 mi 3 22 i '* 2 4" 1 M 3 Jl .17 22 1 4 `2 1 0 0 a ion I *7 1 V* *4 J T, `.i b- 4 T I 3 S loti 1 i U 1 Jo A* JS 4 1 l 1 <t 1 'f. 1 7 t' r. in J4 14 it n 1 4 41 _'7 1M i 4* A 1 4 4 1 <1 3 3 IWi mi 1 H f t 11 1*4 14 U 7 13 7 3 f, lyo lit determinin': the length of fibers present in Owens samples, photomicrographs were used. It was necessary to use this method id mea-urement because of the curvature and matting of fibers in the microscopic field. This difficulty was overcome by using compass pointers and measuring each fiber visible across a given section of the pliotomicrnirraph. The size distribution of fibers, classified by occu pation, is presented in table 0. The libers range from as little as 2 microns (46o. magnification t to us high as 400 microns. The median size-, as may he 'ecu by reference to the table, range from 7 to 16.3. Fulton's data indicates assuming all particles greater than 5 microns to be libel- a median -i/.e of 16 microns. T u ir.E f i -- M n l`iit. h Hflili nf f i l l i* ,<ain[ili,/ tn!h an 0in"< j i t apparatus --------- ( Median 1 lh A ctiv ity a lengl h of | fibers in j I micron* 1 MI'H'::,K. .n-............. <Vrk\.itT'S:'.T.i:2 ... t r-.j i . . I 7 <j Us *h Xo size frequency distribution with regard to the width of fibers present in the air has been made in this study. However, it has been noted, with few exceptions, that the width of fibers collected by the WHS.IJMW rom 1.22 used an ilated an ibrous of microns, ximateiy i table 5 l largely 5. the air of group .> or Total *an re H t<K) 3 1M0 1 llil 3 |e*i V lut <> uo am ples, method s in the ompass n of the y occutle as 2 median to 1G.3. nierons : fibers is been by the 23 Owens jet apparatus was less than O.o micron. This is in agreement with the results given by Fulton, who shows more than 78 percent of the fibers measured by his projection method to be less than this size. dt> t c o n c e n t r a t i o n i .v d i f f e r e n t o c c u p a t i o n -. Jn earlier studies of the dusty trades carried on by the Public Health Service, determinations of the average dust concentration have been of great value , 1/ in describing the working environment, (2) m making comparisons <>f the effectiveness of different methods of dust control, and (3 1 in relating health conditions to dust exposure. In this study 242 impinger samples were taken and counted, and the results have been classified by occupation in tables 8 to is. Each of the occupations carried on in asbestos textile factories has been dis cussed separately in the following section and data for the entire industry have been brought together in table 19. In this industry there are relatively few* occupations in which workers do two or more kinds of work which expose them to totally different du?t concentra tions. In such cases the several exposures have been weighted ac cording t<> the average time of exposure. For example, in plant A. widowers are engaged in the following activities*, willowing, 3 fours: picking. 1h hours; storage-room work, l li hours. These activities are associated with exposures of 2.3, 30.3, and 10.4 millions of particle per cubic foot, respectively. Hence, we may tabulate exposures as follows ami calculate a weighted average: T a b le 7.-- ! **! '.r/wx./r' ir-llmrtr, Annt .1 A < v.ry T im - h .u :r- *r i `5 v v ir t u '- 'l n 't * x p '.- 'ir c M F It .'F/ 6 m ;;:.- -.r jurt v h-ur; :*-r cuh.r 4X^ 9**.S \- h r;2................................___ ... i. I* [ r c u t ' auUirin 21 ir -J ih 4 11 ' M4 24 xt l ;*w cubic foot The average dust count of the 10 samples in the above table, calcu lated without regard to the duration of exposure, would be 18.7 million particles per cubic foot. Preparation.--Preparation includes the occupations of erusbernien, wiHowers, and pickermen. In plant B, these three occupations were conducted in the same room, while in plant A only crushers and u*illowers worked together. Picking uneluding piling), in the latter plant, was done in a sepurate room. The dust, exposures are indi cate in table S. i anWillfBiH^. . -, a t n . M i U ' iHtfiirttttflr if. iirtft' i. tf-' ! iHfgfi . J^ |If-<-Y[*rir jr, T Sable .-- b u s t e x p o s u r e o f w o r k e r s i n th e p r e p a r a t i o n d e p a r tm e n t Ucy>jp'Hi'*n Nur.ihpf of us* e-tift-n5 *ikea M e rc f * The exposure Table rri'hrnit*n............. ... u ........ V ni -a ----------- . .. ' 2 .5 hi U. !*>* n I'd b4, i-r\ i * awrjitfr. It will he n<ted in tsible $ that the mishermens exposure is relatively low. In the plants studied, tins work was carried on near an open door. However, it is doubtful that this occupation reiterates the quantity of dust -flown in the above table. It is more than likely that willow in' and picking urnd even carding! contribute to the dust ex posure ! cru-henuen. Will-.iiiuri eru-hed a-he-tos is not in itself productive of much dust -11.1 i:.u!ioi! p:.i tiele- per ruble foot . Only when waste roving and fly frome \ ejoiiei "ieetor-are willowed does the lu>t count increase. Dust eoiint- a high as u*i million partieles per cubic foot have leen obtained with flv. A iintimioiis -our*-** of dust production results from the manner in which willowimr machines are fed. The material to be willow*-.-, is rai'cd waist high by pitchfork, enuring con-iderable spilling. Willow er- al'' operate -linker -ereen*. A picket-man performs several kimls of work. This is e-pecially true in plant B, where piekermen not only n-si-t in piling (mixing of cotton and a-be~to-\ but also aid in -tacking the material blown from the picker machine into storage bins. This last-mentioned activity produces dint concentrations ranging as high as g ll million particle- per <ubi*- foot. Piekermen usually work in pairs ud alter nate n, !eodi::_' the picker machine and tending to the storage bins. Tiling *io:i-- by both "i ker- together and contribute- to dust counts . i avera Jug W.J million particles. { Picker machines, like willower*. are feil by pitchfork, a method , which produces undesirable dust. This is true even where picker ma- ! chines ha\o hooded feeder boxes. ^ The picker machines studied were equipped with oil sprays, pic- j isiuiuduy to id d down du-t. Thy ineli'ertiveness of this method of ; dust control is shown by tie. - -i ,v - win* li *......! "in uiillioJj par ticles per cubic foot of air............................................................................ , Ca/'iiittj.--The brushing and coiubimr of a-be-to- and cotton fiber mixtures by carding machines creates considerable dust. The carding action is such that small cobs and fine tab* adherent to the , asbestos fiber are thrown into the air. This effect is accentuated by the fan action of the brushes. The granular and nonfibrous appear ance of the dust present in the air of carding rooms has been shown i*1 figure 10. i The average * similar. Counts obtained for son at a relatively Jo speed operations In the two ph all equipment w operation, whirl enclosure was in; at high speeds, e could air flows in amount of valua would reduce tin Sjxtm ing,--Bo similar dust cone (table 10) for ear spinning and vvt higher. T able 10.-- b Mule-spinning % separated fro * done in close j that the dust cou "htaiiu-d for muh '"Workers (4). Spooling, tu'isti Pons generalb obtain a ciear-cui i. 'VM m m m m e m m m m m m rtment The exposure of workers in carding rooms is given in table 9. T lfiL E o f t r o t h r* -o m .'-im a fh p n 'ttrn ht Occupation samples cenrr.itinu taken . (MPPCF. i*s relati.vely ear aa open `iterates the a likely that he dust ex- !j f much dust ving anil fly >ase, Dust en obtained :s from the erial to he ble spilling. ; especially ng (mixing rial blown -mentioned 'l l million arid altee nage bins, lust count- a method ' picker nia- iravs, premethod of illion par- tton fiber ust. The *nt to the tuated by is appearshown in * J! > Oairfers and tenders.......... Stockmen <........................ 38 29.1 I! ' 22.9 ; VVeisjl'te'i a'.er-iie. The average dust concentrations in both plants A and B were similar. Counts as low os 0.4 million particles per cubic foot were obtained for some carding operation's where machines were operated at a relatively low speed and as high as 139 million particles for high speed operations. In the two plants studied which carded asbestos-cotton mixtures, all equipment was hooded and exhausted. Under the methods of operation, which required accessibility to the machines, complete enclosure was impossible. Consequently, exposed brushes, revolving at high speeds, often nullified the effect of the control system. Nor could air flows in the exhaust system be increased since a considerable amount of valuable fiber would be drawn horn the brushes and this would reduce the weight of roving to an undesirable extent. Spinning--llotii mule spinners and ring spinners are exposed to similar dust concentrations. The range shown in the following table (table lOt for each occupation is probably due to the presence of more spinning and weaving equipment where the dust concentration is higher. T a b l e 10--- Dust exposure of workers in mule- and ritttj**pinning depadtutnls Oecupation Numiwroi rm-r c>nsimples <.ear itpoi taken \IPPCK Mute spinning................. King ipiuning ............... l.i id J. y 3,2-* 3 Mule-spinning operations require considerable space and are gener ally separated from other activities. On the other hand, ring spinning is done in close proximity to spooling and twisting and it is possible that the dust counts are influenced by these operations. The results obtained for mule spinning cheek with those given hv Fulton and his coworkers (4). Spotting, twisting, and winding.--The equipment for these opera tions is generally grouped together and therefore it is difficult to obtain gi clear-cut estimate of the amount of dust produced by each., r*m . JMM0M ,***... :a ,. ~ ~ --------------- - ... ftmHMHa 28 The average range of dust concentrations in plants A and B are shown in the accompanying table (table 11), .T a b l e 1 1 -- D u s t e x m u r e o f w o r k e r s i n s p o o l i n g , t w i s t i n g , a n d w i n d i n g d e p a r t m e n t s Otvtip non Number <itUak1. Iefpnlp? ])>*C"ll* eeiif riii n (M I'PC F) Occupation Number satamkopfelnes D ust con centrai itm tM W C F) .....................- . T OV hc}|cr<.... r, 3 2-13.1 Kovne winders............... .. 2i i 2-U.2 \ urn p a rk in .. . -- . . 1.2- HH Vjfn treater.................... 1 65 1.2 3 1.7-3.6 Of the occupations listed in the table, twisting appeared to con tribute most of the dust in plant B and to inUuenee the exposure of sp o o ler- and ring spinners close bv. Twisting frequently produced concentrations of over 20 million particles per cubic foot of air. yet counts below Id million particles were not uncommon. Twisting involves a considerable amount of fraying and when low-grade material' are used, the dust production is increased. Winders and yarn packers are exposed to lower dust concentra tions than spoolers and twisters. Here again, however, because of the proximity of the latter dti't-producing occupations, the amount of dust actually generated eannot he estimated. It is hard to con ceive of such operations as roving winding and yarn packing producing much dti't. l i n x i i l e l i i t h w , n r i eg,--The dust created during the weaving of broadcloth depend* upon the number of warp threads per unit of width, the quality atul width of the material woven, .and on whether the operations are conducted dry or wet. If the warp threads are close, the fraying action which takes place during weaving produces a considerable amount of dust. With some looms the du*t concen tration was found to exceed 140 million particles per cubic foot. Aver age du-t counts obtained during weaving operations are shown iu table 12. Twn-fc 1 2 - - hn*t (spit'iti* of V'orkn& os^ttciattfi with broadcloth wtavififl Ocoupatitm Nnmherof Dust eon- <atnank>eUn>s (Mc&FtrFaCtioFn; )\>tUT. ,f 11o ;.^s j >r. .. . Wh ................................... Oreelers* and helpers................ 1 Inspector and cateaderers__ Cop winders.......... ................ ^t : : , 47-11.1 4 ; 3.6- 9.8 1 3 6 133..f6r--io8..05 ,I Weaving operations are intermittent owing to frequent breakage of warp threads. Consequently, workers are exposed to alternate 1 periods of weavers mi exposures \ , The dusi | trate the d ! wet weavii * However, designated possible to of 4.7 mi)li and wet wt in opera tto j manufactm : havingfro t In view i would he e: ] tions. Tin ! With all h j might canr j culcndercrs 1 These occtt Tuj>e, in' wick, and l T able 13.-- It may 1 weavers ar Weavers, warp threat However, v hoisting ni: parable to facture of : -*3 millioi some distar obtained fo four plants Haor <ivyliiaitfrfMr "~"j -r-r - - B are shown umber of DMuHsCft'rehco'n}^- 3 ami to cotiexposure of tlv produced it of air. yet n. Twisting Ut low-grade f i ?t concentra r. tiera use of . the amount hard to enntuir producing weaving of s per unit of d on whether P thread* are ring produces dust eoneenr cubic foot, ais are shown oM wtaving t ?i aent breakage l to alternate 29 periods of high and low dust concentration. On the other hand, weavers must pay dose attention to work ami are subjected to heavy exposures while the looms are in operation. The dust counts shown in table 12 for weavers and helpers illus trate the differences between dry. and wet weaving. Both dry and wet weaving are carried out on similar looms in dose proximity. However, operator* are interchangeable and are not specifically, ile-ignated a dry or wet weaver*. Under >ueh conditions, it is im possible to gauge the actual exposure of a weaver. The low count of 4.7 million particles per cubic foot given in table 12 for both dry and wet weaving is fur a -u .; ..nr wi t h one dry and one wet loom in operation ~ide by -ide. T- ...be; n.unr* are for a larger plant manufacturing all type- oi .. . ioth a;.u at the time of the survey having from 5* to 12 loom* in operation. In view of the high count* obtained during broadcloth weaving, it would be expected that etvders are expo-ed to comparable concentra tions. That this is not the case, however, is indicated in table 12. With all harms in operation, a- i* frequently the ea*e. the counts might conceivably be higher. The *ame i* a!<* true of inspectors, calenderers. and cop winders who work in the weaving department. These occupations do not prod ,<e large amount* ..f du*t. Toitt, <m'd \ on<! h u h Mi "I irltoj.--The (1u~t exposures for tape, wick, and brake-band weaver* are indicated in table 13. T a b l e 13. -- D'nt 7( /<vur, nf -uV'' 'innj; ir>cf. and hraie-hnnd \ ; - - 11-..' 'i- Of t.K. Mi r'f f Wwr^ivvo.rr<s<'T1l-i-C' x*fc,.. u!2 2i4~' '1> i *-';**>......................... ' j \ j ' i t .iit-!! h'fer* ................. 1 v*> It may be seen from this table that tape. wick, and brake-lining weavers are exposed to lower dust concentrations than broadcloth weavers. Excepting certain types of brake hand*, the fraying of the warp threads during weaving is not as great a* in broadcloth weaving. However, with heavy brake bands, such a* are used on trucks and hoisting machinery, the dust concentrations become high and com parable to those obtained in broadcloth weaving. It is in the manu facture of such brake band* that erecler* are exposed to counts of 20.3 millions of particles per cubic foot of air. Calenderers, being at some distance from the loom*, have a low exposure. The dust counts obtained for the type of weaving here dicused were consistent in all four plants studied. *>** tiWMfcfetiti iiiafttrlritri s' ,< m m m _t-**" 30 Coni. rojH, aw</ working.--Other activities found in the asbestos textiles plants are concerned with the manufacture of special products, such as cord, rope, and braid, and in treating and finishing yarn. These operations produce little dust as may be seen by reference to table 14. T able 14.-- Dust exposure of workers Manufacturing and finishing special prod uds Occupation Nuimmbpeiersof1cDenimt ractoion*n . takelt oord, r>a*. and braid wnrfcers. V 1.2-10.2 1.7- 3.0 The equipment used in manufacturing these products does not operate continuously. None of the operations of cord making, rope making, or braiding require full-time personnel, and a small group of worker perform all these jobs. The highest dust count <10.2) in table 14 i> for braiding. The counts obtained for yarn treaters are influenced by the operations undertaken nearby. Broki-hand finlshimj.--This generates little dust. In the plants studied, finishing operations were conducted in separate rooms or buildings. Dust counts are shown in table 15. T m <i.E 15 -- / ) ' / ' / i . r />ox/r< n f i r n r f ; * r s m a n u f a c t u r i n g f i n hmkf-ban*l lining t >t( upiup.n Nuud r Dim c.itif tmj 1.- ii i.tr-a n Uk, t -M i'l'i'I Occupation Number Du>t cn*f>amuW evutratk* iM Prt'F' Tn-tter and dru r> . i ah nP n r>............. t inn !r-- . - . . . 1 1. * Cutnr* and drdler........ 1 *' 1 1. * Hr.tti'l* rs..................... 1 b- 1 4 2 t `ui)vr>.......................... .... 1 Worker employed in the occupations listed in this table are expoe<! to dust which differs in composition from the dut found elsewhere in asbestos textile plant. Thi~ i- berau~o tin* dust generated by grinders, cutters, and drill*'! * \ ! <:. i m.ok' up of resin, asphaltum, asbestos, and m<",,. ri< a! re-ults for sampl*' 11, table 2.) fi/iscdlar,coits occupations,--In addition to the groups directly concerned with the manufacture of textiles, a considerable number'- workers (engineers, general laborer, dork, and s u p e rin te n d e n ts) ar' engaged in other activities. With the exception of certain forcin'*'-- these workers are exposed to low dust concentrations. The dai;1 presented in table 1(3 require no comment. Oi-cf KLitn2d/nv-r*ff_'___ Watchmen... Stripping clerk i Sanipie? ar, The di i-epresen t plants 1m In the pl carding, a will he di ucarly ev ahestos tu the int finical fii In orde boods att. Imurs. D The dust the courst xhau-it e< niachines difficult t ii'turhant The du? '" dn> inst ' "U llil't, j : '.a . 17 -- 'hi tipat f'n*:i_. 1ll' ||\v ; `' (*> a } -r'lffliff und in the ire of special m. d finishino be seen hv * * ti ng special ; ts does not taking, rope ail group of it (10.21 in treaters are j | j 1 the plants e rooms or . hand lining imbal.T-t[rNHnfmrMriri-o'-fnfn-; I 1x 1I 11..55 are exposed Isewhere in lerated by p of resin, for sample ts directly number of idents) are n foremen, The da ta | | . 1 31 T 16able .-- 'D u s t e x p o s u r e o f m is c e lla n e o u s g r o u p s Occuparinn Number samopfles ` takeo ((PMu'fPiftrP'ioff-T'*rn-; Occupatio Number of satamkpelnes (cDM>t"jP!sftrP:ieCr-;`'F3n* K ar.n^rs---,..................... L abors.-,...............-........) tW*haiptper3m-afnie.f..f.e.v............................... 2 2 11 1.2 YaMnwa............................. 2 0.10 fa Furemen (plaot)................. t1 1..2 >;jp**n'n2rerwh?nts un1i.k-rviv--'-.-- ........2--- -----.-1-2-'- -2' ` f i?auiplrs ant evjwfure? dejn-nil on the acn\ ',:>i with which, they are associated. PREV IOIS 1HST EXPOSCRE The dust concentrations discussed in the preceding paragraph represent present-day conditions. The official ot a-be-to- textiyplants have in recent years attempted to control the dn~: h In the plants studied, efforts have ln>en made to exii.m-r picking, carding, ami brake-hand grinding machines. 1Another plant, wink will he discussed later, has extended the ihc *>f control equipment to nearly every lusty operation *onejrned with the munutacturc ft asbestos textiles.) A know-lodge of the exposure of Workers prior to the introduction of control equipment is important in correlating clinical findings with lust `Xpo-ure In order to estimate pa-t exposure, the air th>w through various hoods attached to carding machines in plant A was shut oif for 2 hours. Dust was allowed to accumulate for 1 hour prior to sampling, The lust thus generated caused much inconvenience to employees m the eour-e of their work. For thi- rea-tut, pormi--nm to -lmt mi exhaust equipment was not granted in other plants stnilied. Carding machines are sensitive to -light air movement- and are eon-equcutly difficult to regulate. Once they ha\e been adju-ted. ativ extern. 1 disturbance atfoet- the weight of the roving prodm-ed. The dust counts obtained under conditions -miniating tlto-e jui- i to the installation of the exhau-t ysteiu are shown in table 17. For contrast, present exposures are included. T able 17.-- Dust counts vinn contru] tiimsurts are usol an*l Inn thz>i are my in i,*# Omipat'.'iU A Vitu**Tri2r c<lu'jj>ft - (M Pi'C F Did' .MprP.-P^`r*rF. D-.-' MHm'F MPi' F CfTi^Ufmiin............ . Wili w,r-......................... Picki-rm-n........................ Card-TS.-........................I *`'2 2 5" 72.5 2 1 Mnle'io.n-r- . .. ' 1 I . : <r'. v r* i < v-. \ a d . I W.-awca........................... 3.9 7\ The low counts obtained for the occupations listed below carders is due to a partition which separates them from the carding machines. ''''" i f ^ irifiiT .Tf^|f1ff^ T-^f- - ^ -- | ......._ Mule spinners are located immediately beyond this partitions, and the dust count shown is due to dust winch has passed through an open door. Three dust samples obtained in the carding room 1 hour after the exhaust fans were shut off gave counts of 77, 73, and 7S million particles per cubic foot. At the end of 2 hours a sample taken in the same room gave a count of 61 million particles. Xo major changes have been made in plants C and D since the start of operations. The lust counts made are essentially the same as those which have always existed. On the other hand, no data are available for past exposure in plant B. This failure can be attributed to several factors, but principally to the gradual expansion of the plant with the growth of the industry, which increased the amount of eqiiipmeut, and the chamre made in recent years with the exhaust system. The first <.f the~e factors appears to have affected all operation conducted in the plant, while the latter is restricted to the carding and preparation departments. In addition, it may be pointed out that plant expansion ha tended to increase dust produc tivity. while the introduction of exhaust systems Inis reduced it. Hence, it may he astmied that the expotnv~ of all occupations in plant B following carding were probably higher luring the study than prior to expansion. It mut alu he remembered that more men have been workim: since the introduction of added equipment than at previous time. INTERPRETATION OF H IS T COCNTS I, The average dust concentration just <liscusscl make a satisfactory measure of dut exposure for m>t purposes. In correlating medical finditur' with dnt expo-ure. however, it is frequently advantageous to expre. the <lut expoiuv in units which combine duration of exposure with averasre du-t concentration. An easily calculate! leeriptive value was developed luring statistical analysis of the results of an engineering and medical study >f anthraco-silicosis (5HIf a worker's dut expo-ure has been unchanged for all practical purposes during his period of employment the average dust count (in million particles pejr cubic foot i is multipliedfby the duration of exposure in years. The product is used as a numerical measure "f his tot; ! tlu-t expo-ure. If a work-: I..:- cha! j>-1hi occupation (and in so doing has changed las dust exposure appreciably] a calculati'"1 such as the one shown in table IS is made. T able IS. 1Plant A. ' Prior to in ">ialnej i|u. The cur a,siimeli a nf implicit 42, fur e \a i to lie talm would lie a The coi culties. ' by contro and in esi difficulties iioccssjirv wIridi dei this requii suitable dc t'e<|uiite a >'fhoods ft 'datively heitlg Sllbj ~.v'teni. . adequate 1 I he dus `O'ClJ oil ' '"dy and ' Vinoer 1 `"f which ' la* of coi lues pert Tlie dust `"inirttnem wiiaaiaMarttek - nbrtfftih*- ttMurmaUai*^^ rtition, and through an tir after the 78 million aken in the 0 since the v the same il, no data "re can be 1expansion creased the irs with the ive affected estricted to it may be u>t pmducreduced it, upations in the study that more equipment ' : j > j | f | 1 , | * 1 tisfaetorv mg medical vantageous hirution of calculated ysis of the lieosis (5 i). H practical dust count duration of nieasure of pation (and calculation \ 33 T a b l e 1 8 .-- Example showing the mrtnoii of computing the Just exposure of asbestos textile workers 1 Occupation of vr-rker Numberinof ' UpUinD Dust count O tP P C F ; Millions of imfiorwtoidte(o--1fv1Iviitacrrs r mler `....................... . C anter........................ Mole -pincer.............. Tot a ........ .......... ) 72. 3 2K- y J> 2a. i , 2.n . 5. 2 32 T 7 FFrl:>inrt A. tu m-tih'vtrjoa of t-xhausi >>* , a,u*rexposure>--o--1------- i 7 Hxyj^fsH l i ^ l 2 - i n tuillk'Q parexl. rr .!>,, h ot The worker whose t-xi"mnv !ias t<cen calculated in table IS would be a lig n e d a value of 2m1 nulla a. nartick-yvars in tabulations in which, for the sake of simplicity, it was desirable to have a one-term measure of du-t exposure; table 42, for example. When average Uu-t concentration and duration of exposure arc to he tabulated separately, a- in table 43, the individual de-ertbed in table IS would be as'-igneil a du-t concentration of 40 million particle- per cubic foot. THE CONTROL OF ASBESTOS 1S T The control of du-t in indu-trv often entails many practical diffi culties. The-e difiieijltie- pertain chiefly to the handicaps imposed by control equipment upon the performance of the work being done, ami in estimating a priori the air volumes required. Both of these difficulties are inherent in the a-ber-tos industry. The arrangement necessary for remnvin_' du-t from carding machine' and from looms, which demand aece~-ihiiity to all parts, is -.elf-evident. Added to this requirement i- the limited information available with regard to suitable design of equipment for each dust-producing >ouree and the requisite air volumes. The latter item is most important in the design of hewnIs for carding machines, inasmuch as air velocities must he kept relatively low in order to prevent the asbestos-cotton mixtures from being subjected to air currents which convey them to the exhaust system. At the same time, however, the velocities chosen must he adequate to maintain the dust below the safe or threshold limit. The dust-control data contained in the following paragraphs are base! on observations made in two plants included in the present study and on data obtained elsewhere by Assistant Public Health Engineer Richard Page (7). The data presented include operations for which control methods have been developed. In addition, the type of control equipment used in England is discussed, although no Talues pertaining to air requirements are available in this instance. PREPARATION' DEPARTM ENT The dust counts presented earlier in this bulletin for the preparation department apply to uncontrolled conditions. A very high degree wmrpwqww!' 'twwm m & m m m ts 34 of control can, however, be effected under certain conditions, espe- j PUttig.-- cially as regards willowing (opening), piling operations, and picking, machines. The crushing machines in tiie plants studied were not exhausted or * controlled 1 segregated. In England. on the other hand, it is customary to enclose meats con- and segregati* <; .-* : jiiipment while it is in operation. 1,(.)'-"> CFM i r ,< ,, ,, .,* , --Willowing machine^ arc often productive of 20 to 5.4 M high du~t concentrations (00 M ITCF i. As has been previously English } mentioned, this dust is caused both by the manual methods used in- ! tothemixti feeding these machines and bv the action of the machines themselves. 1 the type of Conropurntly. a reduction of dust concentration may he obtained by cumbersom using a conveyor feeder which eliminates raising materials to waist ; I'lekthtj- Mg.J8HWg f F ig u r e 15 --E x h a u s t e d P i l i n g S i n s . le\ els with forks ami using an exhaust above the feeder box and below the maohine housing. The willowed material should, of course, be pneumatically conveyed to a suitable bin which is segregated from d>o preparation room. In the case of two machines equipped with exhaust*, it was fomm possible to reduce dust concentrations to 3.0 MPPCF. The exha'-y hoods located above the feeders drew 400 CFM, while the downw"r* exhaust below the widower housing drew amounts of air ranging fr*'11- ( 'EM to c.oo ( 'EM. the latter air How being u~ed on a ffy willow i.See lig, 4.) The air handled hy the pneumatic conveyor was l.s CFM. For the 11-inch diameter ducts used, this corresponds to fl air velocity of 2,7o0 feet per minute. k. -"ii in fi<. ' (in*di--ch, ( 'llo W Il **'.'.ition ; ui found '*11<`i*--7- I: was fo ' award c ' ., a i r i_l* I* " * f ' w l-H - 4 "'iiU'um ,*.i-)5iia,!ir--r--~. i*iLfin .m sy uami'HO O - w w 35 editions, espe- * P'lViitj.--Piling operations are usually conducted dose to picking is, and picking. machines. The dust generated by this operation may be effectively >t exhausted or controlled by - m . d ! t e . b . r t - t r i l c o m p a r t m e n t - 1 ' i ' marv to enclose ments constructed as shown in figure 15 and handling approximately ion. . 1,(]25 CFM of air reduce the dust concentration from an average of 1 productive of 20 to 5.-1 MPPCF. een previously English practice in ; king <enswt* in tiding e \h a \'t manifold* d*-se icthods used in f to the mixture being made 'fig. 16). Air volumes are not available for nes themselves. | the type of exhaust shown in the figure. The method appears to be be obtained bv , cumbersome and to interfere with the process being carried on. :enals to waist } p'.<4: The exhaust control used on picker machines is partly .* ~~ - TS i ii box and below of course, be rated from the , it was found The exhaust the downward a fly widower, yor was 1,800 esponds to an i L i, - '*** F i g u r e 16 --E x h a u s t .. v e n t i l a t o r u s e d f o r P i l i -vg c = e = a t i o - . s PRACTICE!. B r it is h shown in figure 17. One hood is connected at the feeder end and one at the discharge end. The center portion of the po ker is abo exhausted (.not shown in figured With this type of arrangement the dust con centration averages 0.7 MPPCF. This value is considerably hover than found among uncontrolled equipment which exceeds in many instances 74 MPPCF. It was found that hoods above the feeder handled 500 CFM; the downward exhaust at the center measured 1,020 CFM ;.at the discharge end the air How was 450 CFM. Pneumatic conveyors attached to the discharge end of some of the pickers handled 2,0o0 CFM, These dqets were approximately 12 inches in diameter, thus providing for a conveying velocity of 2,550 feet per minute. w X3" ilfi It is possible with special conveyor belts operating between the asbestos-cotton piles and the feeder mixer that the dust concentrations 1 might be reduced below the value of 0.4 .MPPCF, indicated above. C.U5DIXG Two types of dust-control equipment are at present used on carding machines. The first, type consists of a hood which is located directly above the ex- po'til brushes of the machine (fig. f s 1. while the second type is totally endowed and ex s y s t e m U s e d W i t h P i c k e hausted at various lint# (fig, \ c . Studies made of the first tVJH` 'if cxhall't 'V>teins >howed a redui tioii iti dint concentration ratmit.it irotn 72.X MPPCF when no ventilation was applied to 29.1 with ventilation. The air - (|o\\ J. r 1`ii'ii hood averaged ' >7o CFM. which orre- -pumied to dx air changes per hour in the room it) ' which thecard'Werelocated. ' It may be -eeti that the type j of hood and the aif llow used . fed'ti t* the dn-t coneentt'a- * tioti to approximately one- ' ^. 111iI'i the amount created u it!.' \ el.tilatinli. ~ i i . ee.i' id t \ p e o f e \ - i . -\ i-.-d p t o \ ed mure effective than the first in (educing dustiness. The du-t concentration determ ined from numerous samples i ranged from ! to :{.y million particles per cubic foot. This high degree of dust removal was accomplished with an arrangement similar to that indicated in figures 19 and 2b. In the primary fA .,J F i g u r e i s .-- v c p t i c a l E x h a u s 1* v e n t i u a t .i a p p l i e d t o AN UNENCLOSED PR1M ARVC*bo ing Ma c h ine card, hoods a aud b discharge upward. The duct c exhausts front the bottom of the card. The secondarv or roving card is hooded a* * near the at the be lates. 'I the figur In ad. type of s Figure 1 The do exceeding leaves tin roving pr< XXX: r'GURe 2o.- Spool ,,f interfei "aiders (0 " llllN f p ;1I '" n il 10 in tw* flip ent rations Jelow the indicated ist-eontrol ?sont used Tfie first d which is v e t h e e.Y- e machine o*n.| type and ex joints ififf. f the first icentnitinu cd to 29. i J0i Ir-tmWtoHMi fi-iinriMilfal e6i 37 near the center of the machine. The openings d, j and / ' are located at the bottom of the cards and exhaust the bottom fly which accumu lates. The air volumes exhausted by each opening are indicated in the figure. In addition to careful enclosure of the machine proper in the second type of system used, the feed box i~ carefully covered. X ENTILATtON IMARYCARO LS from the hooded at e F ig u r e 19.--To t a l l y En c l o s e d E x h a u s t e d P r im a r y C a r d in g M a c h in e . The design of an exhan-t -y*tem for cardimr machine* is rendered exceedingly difficult owing to the ease with ulmii carding material leaves the roll-, limb air flow* may seriou-Iy affect the quality of the roving produced. Likewise, a poorly constructed housing may create eddy current- which may prove bother.-omc. Any system de veloped require* care and exper iment in design. SPO O U X U AND TW ISTIN ' The dust generated by spool ing operations may he ingen iously controlled by a system of cones in which the spools are inserted and exhausted. Such 2a.~F i g u r e Elevatio n and plan fo r S po o lin g Ex h a u st S y st e m . a system is shown in figure 21. Each case is constructed so as to offer a minimum amount of interference to the work being done. In the case of four Foster winders t2titi spools 1 each cone is 9 inches in diameter across its widest part and 2 inches at the duct connection. The cones are each 10 inches deep. Two hundred cones were found to handle an P i TW aggregate of 9.270 CFM or an average of 46.5 CFM per cone. The dust concentration averaged 2.9 MPPCF. Without the cone system discussed above, the dust concentration for the same operation was 13.1 MPPCF. Twisting machines are more difficult to exhaust locally than spoolers. Figure 22 shows a system which has been partly completed. It consists of exhausting the lower section of the twisting machine by extending a duct with openings along the entire length of the equipment. Each system attached to the machine is intended to -- ----- ( ~ r>-***** ^ '*--- - iTT'-' -- ''***31 4 6f t f i g u r e 21 - E x h a u s t e d s p c o u n g F r a m e exhaust 1.67(1 CFM. Dust determinations to establish the effectivetie'? of this system could not be made owing to the fact that only one of 1" twi-tim: machines was equipped with exhaust and the counts obtained were affected by unexhausted machines operating close by. WEWi.Vb Any system dex eloped for removing dust generated by broad loom represents the accomplishment of one of the most difficult operations encountered in the design of exhaust equipment. Never theless. this has been done effeotix. h * ( in t: .minty and u England. The American system .-liowu schemata aiiy in f i g u r e ? 2 and 24 consists of a downward-draft hood fitting close to the shuttle rack of the loom and a movable upper exhaust hood which operateon the surface of the woven material. The latter hood is actuated to and fro by the action of the loom lay to which it is attached. The hood is connected to the main exhaust duct by means of a flexible air tigli narrow upwa rd iiood Upcr mit MPPCJ istlius e tive. sii trolled centrati 49.7 an 146 MP The F fui- exh dilfcrs frani A tire. 1 -Vitelli -tallona The lo hau-ted haiuis h al th li"ting lame ahi.V. TI -i'l> af t inay he ' licuevi Mie I<lO -.iry. 2 -'.ini- aii C| th is f Ridalli. 1!I - a i... u-U i" Infili ' 'ih ex, \ -tu Ilfiitr, ' '-i>11*M| iu 46.5 CFM per cone. The Without the cone system >r the same operation was to exhaust locally than has been partly completed, i of the twistin': machine the entire length of the e machine is intended to -4 -w4 -'f - ' -----ng Frame to establish the offeetiveto the fact that only one exhaust and the counts hinos operatin'! dose by. ist generated by broad ne of the most difficult lust equipment. X'everi in this country and in - .....- dfy in ngures 23 tting close to the shuttle ust hood which operates hitter hood is actuated to which it is attached, let by means of a flexible 39 air tiirlit joint. Both the downward and upward exhaust hoods are narrow and possess the advantage of high opening velocities. The upward-draft hood connected to the loom lay is segmented. Each hood u-ed. as indicated in figure 24, handles 1.300 cubic feet of air per minute and reduces the dust concentration to an average of 0.7 MPPC'F. The system is thus extremely effec tive. since on uncon trolled looms the con centration averages 40.7 ami mav exceed 14H MPPCF. The English method for exlei .-urn; looms differs oiisiderahly from Am-;can prac tice. In the former sy-tem all parts are stationary 'fiir. 26'. -. Tlie loom' are ex hausted upward by hood- located in front of the operator ami ' ' 11 ! [ * resting a short di-- tance away from tiilay. Tli- hood con '^ '! sist-of two parts which may he turned hark >A i whenever repairs to the louin are nece-- sury. Xo data as re gards air volumes used F i g u r e 2 2 - E x h a u s t e d t .m s t i n g f r a m e in this type of equipment or its effectiveness in reducing dust are available. INSPECTION" In some plants, asbestos cloths are brushed during inspection. The usual procedure consists in brushing the cloth from above and below as it passes over the inspection table. An inspection table of this type with exhaust hoods is shown in figure 26. The hoods used are located near the cloth brushes, ami extends the full width of the cloth examined. They are. however, only one-half inch in width. A study made of an inspection t a b l e su-h as discu-sed ahn\e indicated that two hoods located on either side of the cloth handled approximately 730 CFM each. A third hrush and hood located near 4:us--:;s---- 1 40 the jack spool at the end oi the inspection table bandied 192 CFM. Dust conci These hoo d s reduced the dust generated from a value of 1 U when no technique usi ventilation was applied to a value of 0.5 MPPCF with ventilation. 1 were taken sv Sl'M M A R V O f TH E STVDY O F T H E W ORKING ENVIRONM ENT The ensrineerinsr data contained in this report are based chiefly on a study of lour i('hMo- plants. Data on dust control methods , j { f ? j t t Figure 24.Si l The numher o uid the dust i pre-ented in t: r I: F ig u r e 23 --E x h a u s t e d e n o A iC i.c n have hcc:, -oc-, . i' :;!ci e|l -I- oi || -! l :. " fifth pinto :C -" ..l.deftaKc r * *` (.Canadian tsne'to? 1 eceiv c<t in iun-poin.i. i n* tvlo-ici ^ plants began operations with yarn received from other sources^ were concerned only with the manufacture of asbestos, tape. 1 or brake banding and with their treatment. r dappers to '"pics exceed '``mg and we le handled KJ2 CFM. value of 11.1 when no 'F with ventilation. ENVIRONM ENT 'ort are based chiefly du-t control method' Du-t I 'Uii -ritratiiiti-i were determined by means of the impinger f tecknitjue usinst li_riit field counting. In all, 242 impinger sample' , were taken so as to evaluate the environment of each otwiputmn F ig u r e 24 --D et a il o f e x h a u s t e d l o o m S h o .v n in F i g u r e 23. F ig ur e 25 --D etail of ex h a u st u se o on British t y p e loom The nmiiluT of workers employed, the number of dust samples taken, and the du-t concentrations determined for each occupation are prc-ciited in table Is. The concentrations range from values of u.sti TH LOOM 1 study undertaken in a lirated were engaged in tlv from raw erysouie gs. The remaining tfro? frotn other sources anti af asbestos, tape, braid, F ig u r e 26.--e x h a u s t e d b r u s h in g an d in spe c t io n T able for shippers to as high as 74.3 MPPCF for pickermen.' Occasional samples exceeding 100 MPPCF were found for the occupations of carding and weaving. 42 T able 10.-- Occupational dust exposure of workers in four asbestos textile plants filar micrometer att particulate matter' A otivity and occupation ' v - o rM hs r , itmak|>'wtes ,| ( Mirpa tPioCnF ) | the length of fibers particulate matter PreparadKin; Cru'htrnn`0 1.............................................. \\ illuUTT'. .................................................. Pukvnmn ................................................. C'dDlmi 9 , 2.3-9.5 8 1 *u. M m a y 21 : 34. ^ 74.3 cent for weavers t< median particle si microns. The me<h CarU-O :iinl <<-n,|<Ti .................................. >*<-.vfcrR'tt................................................. >p:nn.T;i.' M!(!*; hyl^r*.......................... King *nm-ts ami IflinTs.......................... iViolitiCTui-i'uu p.MtbTji r\M>DI'i` ...n.<..1..h..v.l.j.n...f.<...,,............................................. Win*bug- 42 ' as : 39.1 Jii 21 a> u ;* 58,* 15 ' 2.6-7. 1f3t 2U 3U,2->li..31 3.2-13.2 | ! distinction could be In most of the } limited almost entit machine*. Data. 1 rrr.xt mI wiipkri..................................... H*aii: ; ss.mfiT?......................................... Yarn i ........ .................................. \ xrn id it t ' ........... ,,...................................... CJotls v <o its* 2f2> H 12 5 1.2- S.O r 2 &1.25 3 1.7- 3.6 ' ` i with which the du plant. An effect iv \\X r- ui<i h*li*f r> i > n ....................... .. . . . ........... i W t ... ... .................. t ifi-i"' t'T . ' ' 17i*iml.it t in mb r- . n . . ......................... t r- . . ... T .[ . v , ' f.n- -* `!el IU|!. W. .' Vx.<o ....... ....... T4 t C, l 22 : 3 4.7-4 7 4 :-n. i 3 **-1" 5 b? f4t 3 fc-y, s U 12 2 4 * 1 1 1 ' * I |j * equipment fitted a effectiveness of <>.\h T ABLE 20,--S u t n / t i i l '' . uh*!t (' w, . Cr,, . . - r r tM-i { .......................... t,\ r..r i. r- ; .i Xr "1 . u..rk< . V'................... 14r,h<-` .* i f'i , X . H il 42 7J~-22:n4.t3i 21 *l i. 2-lw3. 2 F.*jU i"! t}r.- , ' .*i ) Jr i' r*rs .. . . t> - 'i*'> r- ir.-i urilt.T'. Ur ' . r' . e r* ... ... . . ..................... .. .................. . .. 1l tJ, i* \1 l l1 i* 15 411 2 * 1, 5 UPPiialoihnk'gtmti*rg..2............i..f..n..i..n....j. t'ariiHs ip rim ifj > ... ...... .. .,c h1. <f' . . ..r. r- "hipi' . rs. <fc - . ........................... ,U.1, v :.i ;t :g <-it rk> ........................... ^ t *u , . ... . . <)&> s* r mb tp s otbm . . . . .. F.-r* ru*n u.Uut.......... . . .. r |. rk- ................ - .......................... -O UJ t. 7 t 31 () rt 2 2Vy, * 3M2 .1.122 lb a: . 12 sCpaorodliimng: .r..o.v..in..g._._..__. W eaving !>'ro,vU>orn Hftl^her .jhrjpivrcr. . 5 wnh 1'nt-u'ns f ExhiiiidH bin or<-,r ; , *JnJu muuI ("ttp f..r .. T ..t, .......................................... 4M 24.4 . It is evident fr "- - -- - - - --------------- asbestos industry KMHi'uro w. iuhi*ni ro UH* ivut aru njjn j.ibm: br. akuip. <imi j-toraiir bin aomirt.->\ ; Ii,. 'mi* -. \f.n^tir* tiu** ?o nr*rmH*n ui iki r mt<t n j the necessary coir ' '* - t ; - '* *' r " i 'V b ,v r.L! '.tinKir 4u?i t \|H>sure. j use. With the exo of 0.7 million pat T he chemical and petrographic analyses of dust samples were determined from both settled dust samples and sample? obtained directly from the air by means of a vacuum cleaner. Xo great differences in composition were noted between corresponding samjdqs collected by these two methods. Total ash was approximately 77 percent for all the samples. Xo free silica (quartz) could be found on petrographic analysis. Particle size determinations of Owens jet samples were made by three methods, namely, (1) with a eusrope projection device (for de termining the ratio of fiber to particulate matter). (2) hv means of a t exposure in alt oth , Iter cubic foot. I ` to reduce even tin t The following rec< < 1. Dust should j local exhaust hood to reach the hreat > dr. Dust-remuv; concentration to : , have been develop i f 43 textile plants r of Dust conten d>s tratton f.M PP C F) 2V>1, 1M2..^7iaa ans . 1 22.4 In 21) 32.12..2---1s73..3l 22-13.2 1.2- 1Xt.2i'>} 14.7r--4MH., 7i 3J.J**--n*Sll,> 12 24-: l 1341 24.74--xJ\.. ,< 1. 2 In, j I3 4J 1. * 1.:> ( filar micrometer attachment to a microscope (for measuring the size of particulate matter), and (3) with photomicrographs (for measuring the length of fibers>. This study showed that the ratio of fibers to particulate matter varied considerably from a maximum of 20 per cent for weavers to a minimum of 1 percent for crushermeu. The median particle size exclusive of fibers) was approximately l.S microns. The median fiber length varied from 7 to 16.3 microns. Xo distinction could be made between cotton and asbestos fibers. In most of the plants studied the control of the dust hazard was limited almost entirety to provisions of exhaust systems for the carding machines. Data, however, a,tv available to indicate the effectiveness with which the dust problem can be bandied in an asbestos textile plant. An effective method employs the use of hoods and exhaust equipment fitted at each dust-producing source. Data showing the effectiveness of exhaust equipment is presented in table 2<>. Tjfcft(, 20.-- $>nntnni't ct shntt'ttuj (hr <*' 'fi'" ' f*'xt l* '*> r-v > i}t< U r D //* 'f *<i n t , , i ( r t O U t ' ' n i b i t U `* t * l: i n j C - ' t FdllU]!!;*?: \rimtq*r r,f -iu t urC V*M Jt .hm- 'A ' -\- Wfkf'ikkj'vntf2*u.-.g..... . ..... . CC*irri-ri..w\ 2' ...... **^*<n , f-r<- i i - `lu Bna-her iulrn-i*rvr. * "74' 4: *41 -4 7 -1u17. 1 K>4Uv, t**4' 1 " * .v\--r. i f /. or < r* AIn-inhiii.il fi-nt? f*r eiiii ?; it.-l c t*Mv>-\li m>t nut:if- M. ttuples were les obtained 'o great difing samples ximatoly 77 be found on re made by vice (for de means of a It is evident from the above table that the du-t hazard in the asbestos industry can be greatly reduced. It i- further dear that the necessary control methods have been developed and are now in use. With the exception of pickers who are exposed to concentrations of 6.7 million particles per cubic foot under controlled conditions, exposure in all other occupations can be kept below ">million particle* per cubic foot. It is possible with improved methods of ventilation to reduce even the picker's exposure to less than the figure indicated. The following recommendations are made: l. Dust should he controlled at the point of origin by means of local exhaust hoods so designed and operated that no dust is permitted to reach the breathing zone of workers or to contaminate the general ait. Dust-removal devices, which are capable of reducing the,dust concentration to a level of 5 million particles per cubic foot or lower, have heen developed for all operations in the asbestos textile in ! >trv <") . ` mmm mm ... ^ T 1 MMMa t, fiiftiltiiiftitiiili Ititaa 44 2, Since material leading picking machines is productive of con siderable dust, storage rooms receiving such material should I ex hausted. Workers who must enter such rooms while material is being blown should be equipped with approved types of respirators. No materia'. -Iambi be removed from storage rooms while the picking machine i? in operation. .1. Clean air should replace the dust-laden air removed by exhaust systems attached to the equipment. This requires, in event of recir culation of air, that dust concentrations entering any room be kept at levels comparable to that found in outdoor air. 4. Periodic studies of the condition of the working environment appear necessary to determine whether the control methods adopted are constantly adequate. This requires that dust concentrations he determined for each operation. Ventilation measurements are equally important. The work of in-pection and review* should he performed bv per-ons trained for >ueh studies. j j j At the start each worker t< had worked, physical exumi census data (i recorded the w Mmm............. -- (Sonuun) AMnti........... ,, A*--...........Sex.----- Phut ____ ___ _ Age begea work....... . pccrnc joe Pret.. j TwaJ Yean 1 Fig u r e 27.--f i industrial work, stid a line of ques ,!,,i)ein the interv < complete until -'urit>s. The job !"P line of the o -v,,*w he had held att,i any other per :,'ked what he ha< j l,i!"le. The name iiies is productive of con ch material should be exmis while material is bein types of respirators, X0 rooms while the picking n air removed bv exhaust requires, in event of recirering any room be kept at air. the working environment control methods adopted at dust concentrations be measurements are equally view should lie performed 1 STATISTICAL DESCRIPTION OF EMPLOYEES OCCUPATIONAL H ISTO RIES f; j * At the start of the medical examination the physicians questioned each worker to obtain a complete record of all the jobs at which he had worked. This information was recorded on the portion of the physical examination form reproduced in figure 27. After the basic | census data (name, age. sex. color, and marital status) hail been recorded the worker was asked how old he was when he first began 1 j CASE RECORD | Ham* (Sttnuunc) (P in t Name) . Date of birth- Ad&tu ....... A t*.................. ! Plant ________ _________ C o lo r ..,________________ . .Racial Stock................................. _______ ____________________ _____ Addr*M.......... ....... .................... ,, .J * . S. w , D. Sep. Age began work . . . ________ _ Year worked............. --- -- -------------- Time idle.. ccipic jo* *NOUTMT OCCUPATIONAL HISTORY TEAMS OV*t MO.DUCT mou WOMKtftt CONDITIO** contro*. MttA*ues arc Total Year* 1 ..i i F ig u r e 2 7 .--Fo r m u s e d f o r R e c o r d in g O c c u p a t io n a l H i s t o r y , industrial work. This figure was subtracted from bis present age, and a line of questioning was begun to elicit information on the work done iri the intervening years. Xo occupational history was regarded as complete until all of this time could be accounted for by definite entries. The job he held at the time of the study was entered on the top line of the occupational history, together with the number of years he hail held it. the name of the department in which he worked, and any other pertinent data that could be obtained. Next, he was asked what he had done previously, and again a complete entry was made. The name of the factory was entered for each period of em- (4.>) wmrnmmwmmmm** i^ w p a w iiitw mqbwwswm11" -'1Ac.wwmifcj aw* nrwiaiT..... if I li'iMirrrTffflnrr1- iirr~~ --- - ....~~nir .......--...... rfiiim'iiiinil ifiiHi 46 ployment in the asbestos textile industry. After each job had been accounted for. the worker was asked what he had done before that. If a man had worked in an industry in which workers are known to be exposed to pneumoconiosis-producing dust, entries were made in the last column to show what materials he handled and whether or not dust-control measures were in use. Information on previous employment in dusty trades is of paramount importance in a study such as this. Any cases of prolonged exposure to pneumoconiosispmdtieing dust other than asbestos must be treated separately. After the Held study had been completed, an engineer assigned dust exposure values to each worker, following a procedure illustrated in table is. In assigning these values, consideration was given to each job a worker bad held in an asbestos plant. The importance of the occupational history in a study of this kind can scarcely be overemphasized. It is the connecting link between the eturiueeriug and medical studies. The correlations between medical lindimr* and du-t exposure that adeipiate occupational historic- make pu-sihlc provide means for estimating the dust concentra tion* to which workers may be expo-ed safely. Only 25 pci-ons reported previous employment in an industry in whi< h worker* are known to be exposed to pneumoeoido'is-prodtteing du*t. Such periods of employment a*uaily were *o short that no deleterious eliects would be expected. Twenty-one persons bad normal lung-tield markings. Only one of these 2d person* bad a~be*to*i~ at the time of tin* *tudy. a man who had worked 3 years in a foundry and 1Uyear* in asbestos textile plants. COM PARISON WITH O TH ER IS IH S T R IA L W ORKERS Five-sixths of the employees were native-born Americans of AngloSaxon stock and the remainder were Negro nudes. Before beginning work in asbestos textile factories, more than 200 of the *41 per*ous had worked at similar occupations in cotton or wool textile plants. .V large proportion of the employees had worked on farms either before beginning industrial work or in intervals hetween periods of industrial employment. About 15 months before this study was begun, approximately 150 workers in these asbestos textile factories Were replaced by workers with little or no previous asbestos exposure. Although an eifort was made to examine as many as possible of these former workers, less than half could be examined. Partly as a result of these personnel changes, the group of employees examined in this study had an un usually low average age. There was an abnormally large percentage of workers with less than 5 years' employment in the asbestos textile industry and an abimnnally *nndl percentage of person* who had worked 10 years or more in this industry. j ; ; j j j j | , T o ta l............ l*D`U*r L*oveur*... 2t` t<* 4 years.____ to 3 t je a rs ....... -S'Mt* 34 years__ ,,. to 3*.*year - ......... 40 fu 44 year*....... 4f<to 4`*>ear?- ......... .*3to M y esuv ......... ?**to ye-*f< . . . . . rin to ft! year>.......... t tuM M ear?........... To ye-rr-4 ;inf over... I'nkiiottn a:e........ Avenisre.. . etau.Japi lev Tlie low a\ he kept in m factories witl T IrxliMrv A?hettKlevait* Iron ami *teei... vra:i!Te fiu u n c. .. Aorhruite mine-* . Furummir rner> ............. nfFu-e___ F o u m irj................. The avertu asbestos text: which the P> males employ females 30.4 T able Sex and Total.......... . }AJe,bWcirttoee ffmeiimaallaeflsxe_._.__..__._ i i `inirriteliti M I U v t te t* ifter each job had been bad done before that. di workers are known to t, entries were made in bandied and whether or iformation on previous importance in a study mre to pneumoconiosiseated separately. engineer assigned lust procedure illustrated in aturn was given to each in a study of this kind onnectiug link between ? correlations lietweeti fpiate occupational histing the dii't concentre- ment in an industry in eumocoukwi--producing were so short that no entv-one per-ons had these 23 person*. had ho had worked 3 years hints. L WORKERS rii American of Angloales. u tories. more than 200 aitions in cotton or wool employees had worked ork or in intervals be- nm, approximately 150 re replaced by workers Although an effort rs> jn f',r'"cr v.-..i ker3. less suit of these personnel this study had an un*inally large percentage : in the asbestos textile e of persons who had , i \ j j I : j j \ j ! ! | 1 i j j ' f 47 T able 2 1 -- Age distribution of asbestos workers Affe Total..................... Voder 20j nr* ............. 3335030t(ttooo3324o4 year*...... years........... ...... years................... yc:iy................... 40 45 to to 444*yJ eeaarrss...............-.................... S33I tt<o*3*04 yer>................... ynrs.................. 0 t<i M y<rHS................... 3 to year**................... 70years and over............. CnfcnowQ ............. -- Averase........... Mand ird deviation. Number of workers Total White ! White 1 Neuro i malet* i, females j males j 338 : n s j . 14 73 ; 12 2 , *5 ' 28 1 31 ; 324 2ih07 ' 147 ' 10) 4` 0, 04 0I 0n li 32, IN u in jy 83 541 0 17 2124 103 3 3 000i1 , m2* 137 70 h7 421021 15 3 02l 32. 44 ........... . The. low averatre age of this group of asbestos textile workers must be kept in mind in making comparisons of health conditions in these factories with health conditions in American industry in general. T a b l e 2 2 .-- . t o rooe a g e o f trhtU ' m u le itn n l workers ln d u -try ,tg e Vnhhe S erv iie liu llo f.n In d u stry A v eru ie i use PuM nH e tlrli H u llw m A she** T**\t ill* . .. . I n * a n d - J o e d ......................... r r u : . . ' v .- t iT P r id . A n th rt - 'e n u t .. . F u r c u l t tiff .... P o tte ry P . K r . d h e e .......................................... F oundry . *2 1 4J d 3f u < ' :y 2 dy l 17 * >7 * ................. 2 2 K 221 2:*4 l H* 1*2 l*-2 ........................... ................... < * _____ r - .;r .... .... i V i u e n t ................... ................... N o b le r. . .. -- C h w i . d ^ l ............... ........... < l,irr::e u t .. .. 3 3 .3 34 8 3 4 .2 33. y 34 l 33. | 32. h K-2 ><2 1 2 .5 17'. H*2 71 The average age of white male industrial workers is less in the asbestos textile factories studied than it is in 14 other industries in which the Public Health Service has made similar studies. White males employed in asbestos textile factories average 32.1 years, white females 30.4 years, and Negro males 32.4 years of age. T able 23.-- Length of employment in the asbestos textile industry Sex and color ! I ; Total Years employed in asbestos textile industry thLaens1 1to 4 M 5to 'f `t PUo 14 y 15 to iv y 22"*Tyo 2* .* Total............. ....... .......... .......j 511 White males.............................. .......| 321 White Negro females............................ males................ *............ ..............11 Ill 79 73 | 260 44 161 10 59 112 j 17 1 16 | 72 j a s ; 13 1 2191 163 * 2i ij 2j 2, 0e !t 1 001 ftfalTgiifiifffttUofti iigfe1_ix 48 t unm-pundingly. the average length of employment in the asbestos textile industry is relatively short. Only 18.> percent of the employees have been employed in the asbestos textile industry more than 10 years. In the 13 industries included in table 22 for winch information on length of employment is readily available, only two industries have as large a percentage of employees who have worked less than 10 years. This is portly accounted for hv the fact that the asbestos textile industry is of comparatively recent origin in tbis country. Only one of the plants studied had been in operation before 1020. MEDICAL STUDY PR O C EBt'HE A medical examination was made of each worker employed in the asbestos textile factories of North Carolina during the winter of JU3.V3U. A group of former asbestos workers was also examined in order to obtain a complete sample of asbestos-exposed workers. Office worker' amt other employees not expostal to asbestos dust were included in these examinations. They are classified as controls. Included in thi- control group, which numbered 7ti persons, were 27 persons seeking employment in the asbestos industry for the first time. Before making any medical examinations the two physicians made an inspection tour of each factory in which this study was made in order to familiarize themselves with the various jo b s or occupations involved in the manufacturing process. Tbis is a necessary pre requisite for taking a usable occupational hi'tory. Space for examination and thmroscnpic room and laboratory was obtained a t a location a . convenient as (lo-sibli1for all concerned. An improx i-ed darkroom was used for fluoroscopy and for processing the X-ray rum. In ati adjoining room, the medical examinations were made tty two physicians approxim ately according to t ;m f. i'..o\vn ir schedule: F.mr persons at P a. jn.; four at I(l:3da. lit.; four a t 1 p. tn.; four at p. m.: ami four at 3 p. m. In other w ord', about 30 m i n u t e s were re, i:r> -I p *r examination. T: e routine u-ed in the study of pulmonary tuberculosis was followed in the examination of the ciuM. After the history and physical tinling- had been recorded, the group of four was ti 'torosceped and chest roentgeno grams were taken. A few examinations were made in the evening, an d other adjustm ents were made in the schedule so as not to interfere too seriously with the work routine of the employees. At plant A. th e urine of workers was examined with particular attention to amount of silica excretion. In addition to this metabolic study, routine examina tions were m ade of th e sputum of workers in plants B and C for presence of acidfast bacilli and asbestosts bodies. Sections of the physical examination form used in this study have been reproduced in several places in this bulletin as a means of indicat ing the information that was collected. | Each perso ! previously ha of chest disea * FttpQy history of T. | ExjrOMr* to T. B-- 4f Tnue-r<ju|oi*_ - . . Buooptyns_____ 1 fnotmoif____ Lafaenao--. ___ ____ AvottfOBOieWr of c< ToMiUttta ------- ... Ojtttttiofco ______ Rhoomotic Fovcr--- 5 G. X........................ G. U ------------- - KmbRtooI ........ Other aenotu tBnoe Coa|ti --___ ___ ProdBctree_______ DyipM*..... ........ Appetite------------ Strong** *nrr Weight: Stotipnory Other eocopUinU .. Progi-w of aympto- Alcohol ............. _ Toboceo___ _____ Figure 28.--Fr Tabulatior pleurisy, resj rt;r l in the asbestos f the employees more than 10 ich information industries have s than 10 years, isbestos textile try. Only one ). ` nployed in the the winter of o examined in osed workers, stos dust were 1 as euntrols. rsous. were 27 ' for the first ysicians made was made in >r occupations leoessnry pre- a> ubiained at a d darknam i tu t' oitiiim room, the !v accordine to ; four at I p. m.; dilutes were re ary tuberculosis -y and physical be-t roenteenolinp, and otlier rionsly with the 3r attention to m tine exandnaresencc of acid- study have ns of indicat- 49 past medical history Each person was questioned in order to find out whether he had previously had certain diseases which are of importance in the study of chest diseases. FAMILY AMO P A S T M ED IC AL H IS T O R Y <in* mt Oat whm Poimvl FmbiIt M*t ot T. ..................- ..................................................................... ................................................... Exposure to T. B. -- -- ------- --- ------- -------------- --- - *----*-- Tubmeolatia-- T w st**ot-- -- -- - -- --* Pleurisy-------------- Dry------------ -- ----------Sid*--- Hemopt ysi s . . _____ Dot**--. -------------------- -- A m ount...----------------- Atthmo-- ------------Huy F*wr--------- fin n m !* ________--___ Ettpysmn------------ --------Bronchitis................ ............. Sint Di o -- --- _______ ______ ____ _ in Bod___ ___ _____Mom cold* in recont years----------- - Avon* number of cold* yearly-. Tonsil#tie . Hood ChMt . Duration----- :------ --------- Severity--------- -------------------- .Previous injonea -------------- --------- -- . Operations ..Heart Disease ------------- ------------- F n r . . . ......................... Scarlet F*r-. ........................ ..... . . . . . Hypertension.. G. t --------------------------------------------------------------- ..Skia dise*** ^ ___________ _____ --...___ N*r*onirmn -- K eutrnal . . . --------- -- --------------- -----------------Oth*e sortono iUncsms or complaints........ - ............... PRESENT HEALTH C a o g b ____________ Ho Ion*------------------ ----------- ........ --T1 yp*--------------- When worn*.. P roduction ....-................... Amount................ --..................... -Character------------------ ----------- Q 4m ------ Dyspnea............... ................D u ra tio n ...-......................................Seventy.....................................Pm *win*_. Appetite_______ _________ Digestion______ ____ ___ ......B o w e ls ------------------ ------------ Edema-- .. Strength and snorfT........................................ - ......... --- ..................... ............... Herrn*-----------------------------Weight: Stationary........................ L o s t .................. Gamed ........................ How Ion*--------------------- Other complainte ...................... ............................. --................... ........... -----------------------------------*-- `-- * Progresa o f symptoms . HABITS --___ Sleeping . Tobacco ...Eating . F ig u r e 2 8 .--f o r m u s e d f o r r e c o r d in g past a n d p r e s e n t M e d ic a l h i s t o r y . Tabulations of previous illness did hot indicate that pneumoqia, pleurisy, respiratory diseases other than the common cold, digestive .1( .....i^ h^ ) w iwm i^ r m ihiiuimii|I|im>jiwwm miiji.'JIUJiii|)1|IIW!^ i.MWiMIIIIHHW ..LUWWe A iP iW A A S W m < P V ^ n 1 miittMft urite M am m a , MteWVr'rt.V- , in... 50 disturbances, or prolonged contact with an active case of tuberculosis had made people more susceptible to asbestosis. Frequent, disabling colds were more common among persons with advanced pulmonary fibrosis than they were in persons with little or no fibrosis, but this probably is a result of the fibrosis rather than a predisposing influence. SYM PTOM S OF ASBESTOSIS The chief symptoms usually associated with asbestosis are progres sive dyspnoea, cough, hemoptysis, emaciation, weakness, poor chest expansion, curved finger nails or clubbed finger tips, chest pain, and cyanosis. lit these respects asbestosis resembles silicosis. Early cases, of course, would have relatively few of these symptoms and an advanced case would have almost every symptom listed. The appear ance of these symptoms can he explained on the basi- of a mure or less general fibrosis of the lungs and concomitant pathological changes such as emphysema, bronchiectasis, and fibrous pleurisy. The cardinal symptoms if u-be-to-is arc cough ami dyspnoea. These two symptoms occurred together and in combination with other symptoms far more frequently than one would expect on the basis of chance alone. T * ble 24. -- X <//'*<' ut i v v , Iti,} oriniti pm ss u f o>n onori i>*,th f/.t ft . nf(n r w<utt*{ b* *so* <*:*<i to lavt tin m mi ib( boats m* nl>>r *. M7* re //. *i,n* n ho* o>i .'Uih^r oiU j ti}n tjicu id thi o b s u tu i nnHtbir.i appi a ' n bol*i-jace f ifn * ` lbI' 'B- AY* V-ii C.ruih Hfir'.i.?.pty- vi ight pain ^ eticL !.o- ,,f *PS*:;r . r . . i .................... *1.*.......! v.. . Oi* -d ............ I^.*--i*k<r7t -.:5 . . . 122 2*'.4 $4 ' , .1 :r`2 25 || -7> *4 * * m .................. .12 ;;.d 22 .v n x m > - 41' -n v4J ............................................................................1........4..r.i. a4 : j1p1 - - I'-* 4 in ... ................................................. 9 * 42 '* 7 . ................ .............................................................. i a . . . ...................... .. . 4 ; *: 3 :* 51 00 7 2 *'2 4 A r, . As table 24 shows, 94 of the 122 people who complained of dyspnoea had a cough also. On the basis of chance alone, assuming there wasj .'no causal connection between the two symptoms, one would expect5 that 36 people would have both conditions.3 Actually, the two con ditions are found together far more frequently than that, and it is safe to assume that there is some sort of causal relationship, similar considerations hold for most of the other pairs of impairments. Typically, the cough of asbestosis is dry and nonproductive. In ' Tiiii \ .:.ue ha.-* (^k-uUied on the a&-uzupti& that 0.2634 represents the prof ability that any cue of vbe 463persons would have dyspnoea and G.aM represents the probability that a f#r?' a <-u' *y.*.*h(-'-u^b. These values are taken from the second conixnn of htrures of table 24. Then. 0.2^34/ ,* is some cases tlier. of coughing occ disability. At s Usually a con when breathing on in the presem of persons with i due to the seden factories. BIood-streake< to asbestos dust monary tubercul included in table pulmonary tuber Its presence seem prucc--<*- arc goin in the sputum t\\ interpreted ns a > Weakness and prudently of aire* quenev with inen general bodily ap Nineteen of the in their chests wh tress.'- It was v: and it seemed to sharp pain. It di 24 persons with a of this kind. It ; with the cough or The symptoms incidence is ela<d persons affected. aslH'stos textile fa> differed in dust exj ees who were not * the total dust exp* by multiplying the industry by the had been exposed million particle yea to another, a dust lated for each oeci obtain bis total dus *AD example (table Is, ha,- ' I. "HU se of tuberculosis equent, disabling anced pulmonary fibrosis, but this sposing influence. tosis are progreskness, poor chest , chest pain, and silicosis. Early ymptoms ami an ed. The uppear; of a more or less mlogical changes > pleurisy. The loea. These two i other symptoms s of chance alone. 'lerg, compared with hatice alone. Where s appear in bold-face Wtikn<~ r.,,-. 1*1'lit *4 U 1 I? 5 11 j ; 1 1 7 9 1.7 4/ 'i l 5 *I ' 5 0f 2 0 4 J.6 ined of dyspnoea timing there was ne would expect llv, the two eonl that, and it is onship. Similar airments. tproductive. In robability that any on ,.i ?rsoa would h.ivc*:i :uugb. 51 some cases there is scanty, viscid expectoration. Severe paroxysms | of coughing oeca-ionally oecur in cases of asbestosis having serious i disability. At such times highly tenacious sputum is raised. , Usually a complaint of dyspnoea was entered on the records only , when breathing was labored after an exercise test (see p. 65) carried | on in the presence of the examining physicians. The high percentage of persons with dyspnoea who were able to be at work is undoubtedly I due to the sedentary nature of much of the work in asbestos textile I factories. . Blood-streaked sputum occurred frequently among persons exposed [ to asbestos du~t although there were only two active cases of pulf monary tuberculosis in the group. These two cases have not been included in tables 25 and 26 and figures 2d and 36. The absence of pulmonary tuberculosis makes hemoptysis a more significant finding. Its presence seems to indicate that bronchiectatic and emphysematous processes are iming on in the lungs. The presence of asbestosis bodies in the sputum 'which will be discussed in a later section) also can be interpreted as a sign of disintegrative processes in pulmonary tissue. ( Weakness and loss of weiirht are closely related symptoms. Inde pendently of age and other factors, these symptoms increase in fre quency with increasing dust exposure. They are accompanied by a general bodily appearance not unlike that of fibroid phthisis. Nineteen of the 447 asbestos-exposed people complained of a pain in their chests whieh is best described by the term "substernal dis tress." It was vaguely defined and not as a rule very well localized, and it seemed to be an a lie or a feelimr of oppression rather than a sharp pain. It did not seem to be of cardiac origin. Only one of the ' 24 persons with a past hi-tory of pleurisy complained of a chest pain of this kind. It appears that substernal distress may be connected with the cough or the dyspnoea that accompany asbestosis itable 24). The symptoms of asbestosis are listed in table 25. where their : incidence is cla-sified accordim: to the total dust expo.-ure of the persons affected. For purposes of comparison, the employees of asbestos textile factories have been divided into five groups, which , differed in dust exposure, one of them being a control group of emplovI ees who were not exposed to asbestos dust. A number representing j the total dust exposure was assigned to each dust-exposed employee by multiplying the number of years he had worked in the asbestos industry by the average dust concentration to which he presumably had been exposed. His total dust exposure is thus expressed in million particle years. If a worker had changed from one occupation to another, a dust exposure value in million particle years was calcu. lated for each occupation, and these values were added together to obtain his total dust exposure.1 An example 'tul-le Is h.ii tw a c:ven ;q iLe eitiuo entitled 'Interpretation of dost counts.*' P'ljpjJiJ'iJPp'J'ilifMi'JuILtuinmui--Hff*" c' The percentage of workers who complain of cough, dyspnoea, blood-streaked sputum, and other symptoms increases rapidly with increasing asbestos-dust exposure. In all cases the percentage of workers who are affected by a particular symptom is larger than the percentage in the control group. Two of the cases of dyspnoea found >% COUCH **% -----5-4---- 1 **% DYSPNOEA rK r--- %X ! '% ' "1 1 (1 blood- str ea k ed * >*; SPUTU*M% . %% i WEAKNESS 0% - . % *% 0% c h e s t PAIN 2/ - * % - y'/. NO OUST L t s s T H A N CXPOSUSC 25 25 -4 9 5 0 * 9 0 OVC *00 DUST EXPOSURE, MtLUON-PARTICLE-YEARS ' F ig u r e 29 .--p e r c e n t a g e o f p e r s o n s , c l a s s i f i e d b y D u s t e x p o s u r e , w h o Had Certain D isorders in the control group were accompanied hv heart defect? severe enough to have eau-e1 d sdiortne^ of breath. T a ble 25.-- Classification of prift* nt com plpa*nrs****hasccordnto tv the dust exposure of Present ".jdAim to *iu-: M... n 1 .e jer? <ia?r \i**>ure I.O-1!-..inJ ' J* t i. IV '4,? Over ton Tl>tal Nuro- P^r* Num- Per* N:;m- P-r- V i~ - Per* Sum- Per- **-r in--.* l*er >*-v r r r IrT <fLt l*r cent Total........................... 7, ; t. m 519 Coueh................................... .. nx?I`U*ea............................ ... Weafcne-s....................... . Lo*,* of w eiuht..................... BWl-.'r iiie-l *: -*-m . . ... .. f 'lu-t {. , ....................... ... Lost* of ujtw nie.-................ .... f, s. 4 h 01 ,> 24 ; i <>j lu 14 1 7 r* 4* 0 U0 33 .d > * j r 10 ;* > t. *> d2 r * 2t -, 0i\4-i 1 - 1 IV ol*fi ,,* } Yfi Si $& H12O2 lb . 40 M , 44 si : 3* 1s7 3 1 Data not available tor all workers Another indication that these symptoms are an integral part of the symptom complex of asbestosis is to be found in the relation of these sym degree of on X-ray in a later ; ro^ob . first-degre and more longer or which givt F i g u r e 3 0 --f degree great linear mark) Asbestos- cording to t having cert; again, the in ing fibrotic dyspnoea, sit for the respi toms in the ground-glass the lungs. fpppwgw.-.w.' '.mi At-^ - :r^sm m m iw *"* 53 of cough, dyspnoea, these symptoms to the fibrotic changes that occur in the lungs. The increases rapidly with f degree of fibrosis can be estimated from the lung-field markings seen ses the percentage of I on X-ray examination, a subject which will be more fully discussed tom i< larger than the ` in a later section. For the present it will be sufficient to say that as ises of dyspnoea found ' a result of long-continued exposure to asbestos dust the normal or first-degree exaggeration of linear pulmonic markings become coarser and more widespread (second-degree linear exaggeration). Upon longer or more intensive exposure a fine, interstitial fibrosis sets in which gives a hazy, ground-glass appearance to the lung field (first- COUGH ttoo77.. I---- -t'7. --` 7. o v e n ioo -YEARS v Dust exposure, who ' defects severe enough ng to the tjusi exposure of e >*vtr> lu-t nptj-sure r*>tow Over ioo Total Sum* Pt*r- Num Per f>er oem ber cent im VJQ 819 iy I* 3 5 5-5 5 9 *(O11A2J , ' 6t 59 Of l 18 1 112420 4[04 *ft - J1 i r2 /, 5 19 i re an integral part of mini in the relation of DYSPNOEA .'f U . , . >X..4.A n w L v M f .-- \ -N - F ..` ' BLO O D -STREAKED SPUTUM 22!' 5% 7. / y. aa% *' . W EAKN ESS . *% k' 4 d.V.y.*.*.',' * ,r \\* C H ES T PAIN I* L IN E A R 2 ' LIN EA R 0% V Y\ . I* GROUNO GLASS 2 0% GROUND GLASS LUNG FIELD MARKING F ig u r e 3 0 .--P e r c e n t a g e o f P e r s o n s C l a s s if ie d b y Lu n g - F ie ld M a r k i n g s w h o Had Certain Diso r d e r s degree ground glass) and eventually almost completely obscures the linear markings (second-degree ground glass). Asbestos-exposed people have been classified into four groups, ac cording to their lung-field markings, and the percentage of persons having certain symptoms has been calculated for each group. Here again, the incidence of these symptoms increases greatlv with increas ing fibrotic change. Such a relation is entireiv to be expected for dyspnoea, since the disease diminishes the volume of the lung available for the respiratory function. The high incidence of the other symp toms in the presence of fibrotic changes that have progressed to the ground-glass stage is additional evidence of degenerative changes in the lungs. .. HHIIUD W W -- * wiiwp1" Mw 54 T 26able .-- C la s s ific a tio n o f p r e s e n t c o r n p la in ts a c c o r d in g t o lu n g - fi e l d m a r k i n g s o f the affected persons ' Lung-field markings t Present complaint Flr-f-deiree Second*Je<jree F:r;T-<iegTee ,**- T. : linear linear T.-ti! ' Iter X,ruie:li..- rtjerceS. irr X. 1er't`r-: **r Pen.m Tvtal.......................... :il2 :'> 7> 0u*rti................................ 21 \WvHI*?*...-- ............. . ya L"-< <4wv:ght................... y it U ,-puiuni__ .. f'--; ji i.c......................... . i: Iri r, 54 Li a; >.f apiwtiie................. . i : i / 0*1 . *1 yft 7 1* }i n r ! S~ il } 5 0 : ' rui 42 iS n 40 40 ly 2 X-RAY FINDINGS LlWt,-FIELD M XRKIXfi- The <l!i<'ific,-itii>n of lung-field markings u-ed in the preceding sec tion is part of a scheme that wu- used in it studx- of anthnicosilicosis Bor.y fr*tn*wock -- Heart, Aon and Trachea . Diaphr# . . --- - _--------- Lung f ie ld s _______ ___ . . . FLUOROSCOPIC EXAMINATIONS piieumocomosis-j cite miners, for were found. An case xvas found v This constitute' Merewet her chat commented on. whether this difi F ig u r e 31.--Fo r m U s e d fo r Re c o r d in g X -R ay Fin d in g s . t42, .31). It is, of course, highly desirable to have a system of classi fication which will heln in deciding whether a given type of lung-field marking represents an early or a late stage of a pneumoconiosis, and this scheme has been drawn up to illustrate the probable sequence of lung-field markings that occurs during long-continued exposure to a '"5a*nwwi f i g u r e 32. whether it is due excessively high . foot anti more) fi In a typical ca has a fine, gran scribes as `groun the right side tli apices, which rethe cloudiness of ground-glass app with pneumoconi mica,3do not reg characteristic of s topuMished data. 13102-- a s ----- f f lung-field markings of e , Second-ienree SS |. iEruunil daii Tout j eeat* *5?' P" TM* vYt ' -) > *?3 i iT ;'d . 0t 22 l `*> 1* *> Is. -i 6 t ? ; 007 ?? `t wz 12* 4i M Vt V2* b i rittfc?till-Irrfr`'.iT,. 35 pueumoconiosis-produeimr dust. During medical studies of anthra cite miners, for instance, all of the stages represented in figure 32 were found. Among asbestos-exposed workers, on the contrary, no case was found which had programed beyond the ground-glass stage. This constitutes a difference between asbestosis and silicosis that ylerewether i2o\ Lanza (IS!, and Pancoast (201. among others, have commented on. Further investigation will be needed to decide whether this difference is due to a peculiarity of a-ht-sto- dust of i the preceding seeof anthracosilicosis tt etMMtenn ay F in d in g s . e a system of classien type of lung-field pneumoconiosis, and probable sequence of tinued exposure to a <j*m .*CM*** a n Toktv3* 'itviic * MOMW-' 3 ~*Stkw***"***0.* F i g u r e 3 2 . --S c h e m e U S E D i n C l a s s i f y i n g X - R a > M a r k i n g s whether it is due to the rare occurrence in asb.-tos textile milL *d the excessively high du>t exposures . pin to 3uo million particles per cubic foot and more* found in certain other dusty trades. In a typical case of asbestosis the lower half of the chest X-ray film has a fine, granular appearance which Merewerher t2'>) aptly de scribes as "ground glass." Not infrequentlv. there i< more fihto-ds on the right side than on the left. The presence of emphysema in the apices, which remits in ineiv;,-ed radiolttceuce. tends to exaggerate the cloudiness of the bases of tne lungs. Kmphysema precedes the ground-glass appearance of the bases. Chest X-rays of individuals with pneumoconioses induced by other silicates, with the exception of mica.5do not regularly show the basal localization of tibrosis that is so characteristic of asbestosis. >f ! t. 4S102-- --.* a tfM li -T,. . ..." " " OG Occasionally, in an ashestotie chest, the heart has a shaggy outline when viewed roentgen*graphically, a phenomenon discussed by other investigators. This seems to be of more frequent occurrence when the worker has been exposed to dust containing a high proportion: of fibers (the dust produced in twisting or broadcloth weaving, for in stance) than when he has been exposed to short asbestos particles, l no dust expbsdftg'l c o - g /' ' - ' '............ -* ....... II... ' ;.I 3 30-3? ' ' ....... ' 20-2# I mi i 'I ' '| OWOEB 21 '... ' t 0 l9 2 0 3 0 A O SO 0 30 0 0 0 100 PCt*T 1 K a o lin ) 50-5 - as c 3C-39 " ao~asv ' .... L-Nocf* go ~' ~ ~~ " 1 ~ 7"' " ; ~1 ~ ' " 7"T .: ~ " '........ ~ '.? 0 0 2 0 30 A Z To ~ 60 70 9 0 *C 00 50 - 59 A55CST0S 20.29 y!y'r V*DCAat "7 C 10 2 0 30 4 0 5 0 90 *0 9 0 0 1QD u : - -.* t s t et4 tt *tcc.c ctiR tt t* m w SI,.9 5_*4S 6*0aiD&t*I UNt* F ig u r e 3 3 --p e r c e n t a g e o f m a l e s C l a s s if ie d b y a g e , v. h o Ha d C e r t a in E L u n g - f i e l d m a r k i n g s 2 2 9 M e n m a 'd n o p r e v i o u s i n d u s t r i a l D u s t x p o s u r e 80 h a d b e e n Ex p o s e d to Kaolin D u s t , a n d 357 Ha d b e e n e x p o s e d t o asbestos Dust such as those produced in carding. Further studv would be necessary in order to establish this point. t; , Fnlike silicosis, n<"hilar and conglomerate shadows are not fouijtd in asbestotic workers in the absence of tuberculosis or other infections. The principal difference discernible on an X-ray film between an early and an advanced stage of asbestosis lies in the density of the ground- glass markings and the degree to which the linear pulmonic markings have been obliterated. Although first-degree and second-degree ground-glass markings b a t e been t.ib n ia ie u -e p a ru te ly in se v eral tables published in this report, it is often difficult to decide whether a particular film repr< fibrosis. There is, of cours advancing age. Be which is indicative important diatom-.: < fetation of this condi published data colle* lung-field markings ii One group comprised trade; the other grou kaolin by wet metlm degree exaggeration advancing age. It i of 3! men there we Other studies confirm ! to marble d u -t: Is per , had sround-glass or i '42 for 2(H men em amine*! by Gardner ai of discrete, nodular ft! In every age group f advanced stages of pu exposed to ashest**.- di lung-field markings imfor the two occupatio between tiii- condition reason why the imidei luted with age is that t T a b l e 2 .-- H* t i t m u / /.<> ] factori** inf iht Jtr*( tn I*re\ p. Per- Ace epttt Xurn- wuh trer first- Of >!.- men lme.*r ttmrfc* tOg* Totalesammed-- 22 Stf JVOn1der so___ ........... A lto * ........ ` V v ................ fa. JOT lis Ml iT 'OU.Vd__ 2 1) l mwwm ^ l l iMllIlC**"" 57 uis a shaggy outline l discussed bv other nt occurrence when l high proportion of oth weaving, for int asbestos particles, f 1 j ; 3 i 9 0 100 3 i ____ 1 > 90 O 1 ' 9 0 100 D tc n a e . W h o Ha d c e r t a in in d u s t r ia l D u s t Ex . 357 m a o b e e n E x p o s e d .would be necessary | ows are not found in or other infections. 1m between an early nsity of the grottnd:pulmonic markings . anti second-degree | ? `paratelv in several to decide whether a particular film represents an early or an advanced stage of pulmonary fibrosis. There is, of course, an increase in the prevalence of lung fibrosis with advancing age. Because ground-glass appearance of the lung fields, which is indicative of fine, interstitial pulmonary fibrosis, is a most important diagnostic sign of a^bestosis, it is necessary to evaluate the relation of this condition to age anti other relevant factors. From un published data collected by the Public Health Service, tabulations of lung-field markings in relation to age were made on two groups of men. One group comprised 220 men who had never been employed in a dusty trade: the other group included M>men engaged in mining and refining kaolin by wet methods. The percentage of men who have a seconddegree exaggeration of the linear pulmonic markings increases with advancing ago. It is significant, however, that in the entire group of 300 men there were no eases of ground-glass lung-field markings. Other studies confirm this. Dreessen (4oi ' examined SOmen exposed to marble dust: IS percent had second-degree linear markings, hut none had ground-glass or nodular markings. Similar data are available (42) for 201 men employed in portland cement mills who were ex amined by Gardner and Sampson. Xo eases of granular markings or of discrete, nodular fibrosis were found. In every age group the proportion of asbestos-exposed men who had advanced stages of pulmonary fibrosis is greater than in the men not exposed t<> asl.e>tos dust. The percentage of men with ground-glass lung-field markings increases with advancing age. In view of the data for the two occupational groups just discussed and of the relation between this condition and length of employment, it appears that the reason why the incidence of this type of pulmonic markings is corre lated with age is that the older people ha\e been exposed to asbestos T a b l e 2 7 - R d a t t o n oj ln n g -f i* h l w a l k i n g s to ag M i n s u k t n g e m y l m u n i n t in a d u s ty tra d e f o r On fir st tun*-, k a o lin irorkt rs, a n d no n t rnployed in asbestos textiU /adorns S o perxepvoiosuursetu*t wotkers Asbestos workers Age Num ber of men Per cent with firstdegree linear mark ings Per wceitnht I sec doengdre*e linear Num ber of men murk- tugs Per wcesntht fir-tdecree linear mark- Per wceinrht set onddecree linear mark ings Num ber of men Per cent with firstdegree linear mark ings Per- Per cent cent with ec- 1wir<uth- oud* decree srw gnyad- linear murk- murk- **1 ' s Per cent with 'Z TS? Total esannned... 2a 92 i s su 79 21 359 fil < go 1* 1 8 tinier 20.........-......... at to 29....................... 58 93 107 ' 93 I 7, a: 7' 29' IDO 93- 0 7, 1It : 30 to 39....................... OtoJO...................... '0to 39 ...................... 38 IT 1 90. SSI 7 57' to: 12! 33 i 23 812 ,58 , 35 33! 112 38 50 50 ' 17 73 27 78, 13 52 ! 23 30 23 33 2 , 0. SI 17" 233 12 0 8i 12 24 8010 09...................... 2 100 ! 0 3 100 0 , 2 50 0 0 30 n pi'jii'jmmgnowuj mmmrn> , vf. cv 58 dust for tlie longest time, It would he important u> know whether susceptibility to asbestosis varies with age, but tbe~e data do nut-seem to be extensive enough to test this point satisfactorily. The prevalence of ground-glass lung-field markings increases greatly with increasing length of em I ploymeat, as figure 34 shows* The incidence of grmuut-glass 49*/. lung-field markings also in creases with increasing dust exposure. ;'V In future 3ft, which is based on table 2N the heights of the vertical bars represent the per- cent;ures of a-he-tos workers in I-- ^ .CN5i*-'9*Of 2- 4 rrasosv in ts F i g u r e - - R e ^ a t o \ o f G r o u n d - G l a s s L u n g -F ;eld m a r k in g s t o l e n g t h o f different exposure groups who had gmtmd-gia.-s lu n g -fie ld markingsof cither first orsecond degree. The Tfi controls have E v PLC'- V E N T l>een excluded from this tahula- itcl a number of worker- whose dust expo-ure was not known IlilVf also been omitted. Many of the percentage values must he viewed with caution heeau-e they are based on -mail numbers of worker-. This j- particularly true in the groups with more than inCv*oena-ri.~d'erei.umgp*ltoh*yemfeonut.r 30p- dust exposure groups one at a time, there is a eotisi-tent and regular increase in the percent age of per-on- with ad vanced stages of lung PRCCnTaC cp aobpErs rcECTtO fihrosi- with increasing length of employment. Age. of course, also in creases with length of 0-4 5-9.9 5-19 9 CvB 0 employment, but these oust concentration million particles pe r cu ft ffbrotic changes cannot f ig u r e 35.--r e l a t io n >o f g r o u n d - g la ssi l iNG- he ascribed t^o ~ad,vanc Field m a r k in g s t o Ou st Ex po su r e . ! ing :._e hee.m-f. ;i- table 27 shows, fibrotic changes of this degree are tint t<' hecxneeTeii in u nrkmen of comparable age who are not exfiosed | " "* "l- ( ) -lete Hie _Ie.i l di'iotetiOe- between individuals ill the time that elapses from their first exposure to asbestos dust and the time that fibrotic changes are evident on X-ray examination. In some persons this wa much less than 5 years and in others it appears ll'TilimHItfiT 1'thmfTfrnfil iMHiVi ;< h e m o r e t h a n ,lirfe!vnce- entire in physical exerti< occupation, shall respiratory needijuently fewer as muscular work r individual difiere enees in the total F ig u r e 36. --in c id e TO L.ENG T able 2v ~ i`ti'1-mhi-ujvriitlli' | \IT- U* -i . K \ J km -j . . I IVrt-Tifag . f1W-e'f l... I 'rn lif.igo lArT.ft.fi... !jI;nrm...il.li..10 <.s-r3m.. -iFKtT\|ckt-sn*i*n.1g.y. I t wifi h e III, incidence (,f ii Even if length incidence of gn million pa I -- -- wiPH!l!pa.|WEMi*iTiim;.PNPj j a ^ m p p 59 it to know whether :se data do not-seeni ily. ngs increases greativ sing length of enis figure -34 shows, em-e of ground-glass markings also inth increasing dust to be more than 10. Althouirh it is impossible to account for these differences entirely, it is possible that one factor may be the difference jn physical exertion that different occupations require. In a sedentary oecupation, shallow breathing might be adequate to meet a person's respiratory needs: such a person would inhale less air, and conse * quently fewer asbestos particles, than a person engaged in vigorous muscular work who was obliged to breathe deeply. Some of the ; individual differences to be found in these data may be due to differ ences in the total amount of asbestos dust inhaled. 3d, which is based !. the heights of the s represent the perasbestos workers in (posttre groups who i-iriass lung-field either first orsecond he Tti controls have ed from this tabulaurc was not known ure values must be 1 small numbers of (>s with more than * . j I ' * ' 10-199 09EB *0 IIU.IO** 9ARTICUES Ptn Cu FT Gr o u n d -G la ss lu n g Du st Exposure es of this ilearee are n Im art tun exposed i J f n individuals in the bestos dust and the iy examination. In I in others it appears i f i g u r e 36 -- I n c i d e n c e o f G r o u n d - G l a s s L u n g - F i e l d m a r k i n g s in R e l a t i o n t o L e n g t h o f E `.<p l o v m e n t a n d D u s t c o n c e n t r a t i o n T able 2?v ~ tn*u a^bt "t*** *nuly u'/th tjrtmtfl-fllii!'!* lnht]-jb hi rn<11L / lMi'.r\i<o'UP- niill'Mi I-.p '-|-rt*tr Y- if' -n -I.-''"*indn-'rx IMu 4 * M In I I > UV.-r 15 | uT-l'i-I Oto 4 y .. . ; K \ | mimi .. i Pert- msiw. iAlTivh-l .. ........ l K\|v**ill . i Ft n-em .uv | Atr-vTL lorn h i'i Kk|*ov,ui . I Pt-rn-nrasn- Over 20....... | MTi'dt 'l iP m v m .i.'i' 1) n 0 H u I 4 (l : ` 7 ` 4 Mi Id ti '/ , ; v , 5 .' b'71 d42 *<0 li 1 o' < /r , fi 17 <* -{I U h ', tiy , 57', 1 * It will be noted that the relation between dust exposure and the incidence of ground-glass lung-lield markings is not a simple one. Even if length of employment is disregarded, as in ligure 3->. the incidence of ground-glass markings is proportionately lower at 10 to ! 19.9 million particles per cubic foot than it is at the next higher or M - ii inil 60 next lower dust concentration. Although it is probable that these differences represent sampling errors due to small numbers of exposed persons, it may be that asbestos fibers excite a different, and possibly more severe, reaction than asbestos particles. If this were true, the total particle count tabulated above would not be a completely satisfactory measure of the pneumoconiosis-producing power of asbestos dust. It is not unreasonable to suppose that the amount of pulmonary fibrosis might be more closely related to the weight of inhaled asbestos dust than to any other physical property of the dust. The number uf lust particles can be used as a rough estimate of the weight of most dusts (laboratory studies have shown that the two quantities are hisrhly correlated I. This may not be as good a measure in the case 1 . \ , t , j ' I During fhioro-n ment of the diapl of people with i increasing length severe degrees of T able 29.-- Occurrti N'ormtil. . <f Dfgr<n- r.f: Total Xonwil......... _ 5Thp [KTontiig** ir F ig u r e 37 .--R e l a t io n o f D ia p h r a g m a t ic F ix a t io n t o D u s t E x p o s u r e T h e P e r c e n t a g e o f p e r s o n s in e a c h E x p o s u r e G r o u p W h o w a d F ir s t , s e c o n d , o r t h ir d d e g r e e D ia p h r a g m a t ic F ix a t io n h a s Been R e p r e s e n t e d by t h e h e ig h t o f Ve r t ic a l b a r s * ! of a'be<tos because, as table >shows, there are many long fibers in the dust suspended in workroom air. The difficulties encountered in measuring fibers have already been dbrtissed (p. 23) and only one additional point need bo mentioned here. A fiber ">() microns in length is capable of reaching the lungs (table 37 ); it would be counted as one particle in making dust counts, and yet it would have approxi mately Ad times the weight of a fragment of the same fiber only 1 micron in length. The 2 particles would have the same influence on the dust count, but one would carry oft times as much asbestos to the lung as the other if both were inhaled ami retained. Lnfortunately, measurements of the weight of dust in the air were not made. If they had been, it is possible that the relation between asbestosi- and dust exposure might have been altered. j ; 1 , > | - This is shown in into five groups km amounts of ashe-ti their working life. of diaphragmatic i normal diaphragm: or severe (------- u, Percentages have b. Severe forms of stages of lung fibre lung-field markings merit. Of the 22 p markings, (8 percen a reasonable finding "Ppear to lie part ol ; probable that these 11numbers of expose*! Jifferent, and possiblv If this were true, the not be a completely -producing power if amount of pulmonary gbt of inhaled asbestos te dust. The number ; of the weight of most ie two quantities are a measure in the ease ********** O**mv**e**nu**i**oo to Du st Ex po su re The > \t\ h o H a d F i r s t , s e c o n d , jeen R e pr e s e n t e d by the many long libers in the culties encountered in I (p. 23) and only one A liber 30 microns in 7 : it would be counted it would have approxi' the same liber only l ave the same influence tes as much asbestos to nd retained. Unfortuthe air were not made, tion between asbestosis 61 diaphragm During fluoroscopic examination of the chest the degree of move ment of the diaphragm was observed and recorded. The percentage of people with impaired diaphragmatic movement increased with increasing length of dust exposure, and the proportion of workers with severe degrees of impairment likewise increased. Table 29.-- Occurrence of tiiaphmgmah'c fixation in relation to million particle years of exposure 1 PERCENT Desiree of fixation Controls M0knpartid" iT*t4y *nro*.JM Uu-rPiO N orm al. >U4li `n }T Doanvoffixation Nl'MBKR OF Ca^KS .Mil:,!*|trn(`!<*year* Cmrd< rniitT'Jo* t" 40 lilil '** OttT l'#> Total Noraiai............... 1*2 4J V. IIliI 12 31 17 i Tho fH-rtt-n' v vilu-- in tin* ifppT hUf of U\L> t xl-h. n .n nm! ly "total ` In ili \.iiu-* m ilv lowi-r iulf.-t mi* fuM- iho valuer labdk``i This is diown in fisrure 37 where n*he-t**< workers have been divided into five groups lone <>f them a control group), according to the total amounts of asbestos dust to which th e y have been exposed during their working life. Only two of the 70 controls had any impairment of diaphragmatic movement. For each group the percentage with normal diaphragmatic movement, and slight (--). moderate f--- ). or severe (* --r-r) diaphragmatic fixation has been calculated. These percentages have been represented by the heights of vertical bars. Severe forms of diaphragmatic fixation accompanied advanced stages of lung fibrosis. Among 293 persons with first-degree linear lung-field markings. 9.3 percent had impaired diaphragmatic move ment. Of the 22 persons with second-degree, ground-glass lung-field markings, 6S percent had impaired diaphragmatic excursion. This is a reasonable finding, since lung fibrosis and diaphragmatic limitation appear to be part of the same process. 'WWW-1w,... 62 Diaphragmatic abnormalities, such as peaking, did not occnr to any significant extent in asbestos workers although they are common among persons with silicosis. In a study of granite workers carried on by the Public Health Service <4v p. S7 i: '`Irregularities of the diaphragm were rather constant. Forty percent of cases had evidence of it. and as the condition advanced there wa- an increase in changes of the diaphrag matic shadows. There were instances in which angulation of the diaphragm was in evidence, and others which showed indications of extensive adhesions," In a study of anthracite miners carried on by the Public Health Service nil. p. 5s; "Decrease in the motihility of the diaphragm as demonstrated by fluoroscopy a- frequently observed, Tin- malfunction, varying front slight to practical fixation, increased with the severity of the pulmonary pathology. Not in- froquent Iv adhe-ion- between t!ie vi-ceral and diaphragmatic pleura could he -ecu.' On the contrary, in a-be-to-i-. with the exception of one man dig. 4-'. ti d e wa- no roeiitgchographic evidence of dia phragmatic peaking. It appeal- that the limitation of movement, which i- a definite part of the -ymptoin complex of a-be-to-ts. may be due to inela-th ity of the ! mg- and binding of the iiing? to the pariotes and the media-tmal -tne-tuie- by fit.rou- pleuriti-. See pathological section.) phi-k %i. FisutNf.s The objective -ym ptom - that are tno-t frequently ob.-en ed and most u-elul in e-taK i-hing a di.igiio-i- of a-be-to-i- are general appearance of ill health 'particularly any -ign- of lo-- of weight ). the condition of the finger nad-. and dimini-hed che-t expati-ion. Fiic-e -vinptoins ohviou-ly appear late in tin- <o".r-e ot the di-ca-e. The u-rful chest rigti- seem O* be limited to adventitiou- sound4. Dimiui-hed breath rounds, prolonged expiration and crackling rle- over the bases of the lung- am; inter-cap .i..r :t_i"ii- -ecu. accompany a-he-tosis. Various rle- and ndvetititioti4 sounds were heal'd in the fie-t- of jiereeiit of the per-oii- in the control group, liait-- were noted in 14 percent of the a-be-tos-expo-ed person- who hud normal lung- field marking- or who had only lir-t-degree linear exaggeration. However, in the group of person-with ground-glass luag-iield markings (person- who laid a -b e-o -i-1. 4h peieent had rales or other adventi tious sounds. In about two-fifth- of the ea-e-. rle- per-i-ted after cough <'i __;_: _ ;..!! --..c, >. Ce ..le !.a:>: t o e v a l u a t e , probably tiec.-o: t h e C . , " | o ' i t' :: _ g i v e ; <' .1 !:"'< i- c o v i t e ; balanced i,. .i,y- ... . . !.: . .- - U 'O-'V.,,!!,: .... The a o - e t i c c ol lo- ...,/.eo a t e a - oi c o i , _ m i u e i a t e h v r o - i - and localized areas in which there is marked compensatory emphysema obviously ac counts for the lack of more definite findings. ; f ' ; ' |*l ] | ^ ) Chest expansii increasing pulim into fotir groups expansion and tl for each group. General Appexranee---------- Sion and mucous membran. Eye* Pupils regtriar----- Ears: H e a rin g ..I---------- T e e tb ------------ ------------- Glands: Thyroid, Nernud. BJood p re s s o r* ..................... EreretM regular PulM' irregular Respiration .. _ Chest; Typo-------------------Expansion__ . ___ P a l p a t io n -----------Cireomf.: Inspiration Expiratior Expansion Heart: Sint, Normal_____ Mormon --............................ R t m ia ____ _____________ Extremities; Clubbing-------Special marks of identificat Remark* __________ ____ - F ig u r e 38 lia-i- of lung-field u e.-r,jtv era;. f large-chested i vaneed pulmonary increases slightly pulmonary fibrosi I ig, did not occur to anv hoy are common iniiWl',r >rkers carried on by tin s of the diaphragm were idence of it, and as tla> UHiges of the diaphra^lich angulation of the showed indications of e miners carried <>n bv ise in the motibility of copy was frequently ht to practical fixation, c pathology, X<u in diaphragmatic pleura , with tiie exception f iphic evidence of dlalitation of movement, x ot ashesto-is, may be le lungs to the parietes tis. (See pathological itly ohserved and most ire general appearance ight i, the condition of on. TiicM* symptoms )~e. Tiie u-efnl chest Diminished breath I"s over the hases of iccompany ashesrosis. card in the chests of Kales were noted in ho had normal lung- linear exaggeration, ss lung-field markings ales or other advetui, rles persisted .o'r o evaluate, probably >te is counterbalanced yper-resonance. The is and localized areas lysetna obviously ac- 63 CHEST EXPANSION" (.`best expansion v, no n< m ,-m ! :-t exposure and with ucreasing pulmonary hbro>i-. A-oc-io--. o men wore divided into four groups according to dust exposure, and the average che>t expansion and the average chest girth at expiration were calculated ;,,r each gro !P. Tic- - mo im-p wore classified into four giou'ps mi the PHYSICAL EXAMINATION U j pma Bft.. ,,,, Wt>-- * Cl* Wt----* G eoenl A p p w n n c * -.-- ............................ - ................. " Ejr* * .................~ Stop ad mucoM mnbwuMi..............------- No--- ---........ `........................Moothbw % r -- E f a Pupil. n r > U c . .................u n t i l * . . - .................... E' t * R ............. U ..............G t a **.......................... " " B .O : H e * ...............1......... D u c k * .............................Tomil-.................................... - ......... P k K W s * .......................... _________________________ Gam..................................................... PjOTtak-..................... ......... '------ GLadit' ThjraUi, Norm...............................Cervical----------------- EprtW skW ...................-- ................... Bkw4 p r e w a r ----- ------------------------------------- Ex*+t%** Bat*atr**t Pali*: rirerfeugUu,lfar Eetjnretioo E**rCU* After t mtmaU*r**t H efm A ............................................................................................... Enlarged Stag ErtomiU: Clokkm*------- --------...................................... "*** Special merlu of identifie..................................................... - ............................. ........... Bieuiut........ -........ -...... -.......... -................ Examined b y : -------------- *---------------- --- --*--------- - F ig u r e 3 8 .- F o rm u s e d fo r Re c o r d in g p h y sic a l F in d in g s . basis of lung-held markings, and simitar calculations were made. The decrease in average chest expansion cannot be attributed to an\ lack of large-chested men ini the groups with high dust exposure or ad vanced pulmonary fibrosis. On the contrary, the average client -itu increases slightly with increasing dust exposure and wi:n im-iva-it g pulmonary fibrosis. Several factors may have voturip tied oi t:.c m m ta tm m tm ttis MalirvirriTi,wifto(tfian*,itt*'i fiH>AWH Nk, *ryIttflMfc 64 :L.rrt-r phenomenon anil the available data provide no means for ,li-riminating between them. Since the trend is slight it may be disregarded. The ratio oi chest expansion to chest girth decreases with increasing dust exposure and with increasing pulmonary fibrosis. T able 30,-- Kdation of an mg* dost isyan-'ion to dust d / m u n in male asbestos workers Dust exposure,millionparticleyears Lc-Ihan - 5m4 otoyy Over J00 i- . . AJ,.t7*721 S3.U!HI :M2..OP>Tyi\* *4a,.n3Mr.y * %} t 31.-- A*,at >' ni*'00* c** io Inug-fitld tt'firkiog* in male >i*hi>u>* tm k*'n l.tma.frMl ..-.rVamo F-r-'-l'krOt er*'.nroi,tr- *rg-r-.-.'EITl'l?.. r*eifn.und M*M> - - r' ___ ___ , ... .. __ __ vt i1:i*:w7 ,uJ _ii'tTJt'i . ................ ............ di ''** .2t i1tt0'cj -- - --- -- (.Te-t expansion tend' to decrease somewhat with advancing age, .t tli.* veraire chc't expan-ion i- less in asbestos-exposed men than :: i- in men of comparable aire who have not been so exposed. T'Bi.e 32. -- -lo.iiu. e h d expansion o f male* Fv;v.. i-ko...t> Fttf-;i-di.?-.:)o*M\hfioi1f'itmn>1-u3rvt-iJiu.?|T.;dio> F-wh-<<1fit'ot't;l:*tlesto? As.* :\ -r:rt'..Nfi'*)r'4_-* <A;.'*o4fr*.u' -**t Vre..rnnn.:fun*pr;u:n<f A,l.i*c-'rt.mir.ot-t*vi Nn.uJ'miolbif; r.*o*f eAph.'m-e*.rr*aiuesn\e- - -- -*.>. ............. .... ;oVsi Il Jid*-*hy 12H11:* 2]*74 32 1 IhcH33,2Z2ti.*.,.*.1(225w4.1M4*' pIV4lb7*y2.i Juchtd22222s,.,..26(3V^W>S7 11 jl Externally, the thorax show- evidence of limited respiratory movement: the supra- and infra-clavicular fossae are conspicuous; the anterior-posterior diameter of the chest is increased: the suhsternal _> may be n-cire obtu-e: evidence of wasting or loss of subcutaneous may be pre-cut; certain oi the accessory muscles of respiration m`r ; | !I j may appear to be hyp* appearance of the chest iAmong the conditions tin adhesions and the relative The direct effect of pub seen in table 33. Before t with ground-glass lung-i".*1! so, than the respiratory r.r tion of pulmonic marking, the subject stand with one other foot to the level of The respiratory movomen preceding the test, during cise. and during a M-seeon raised the respiratory rutt respiratory rate ws depen the men with ground-glaAfter 2 minute'- rc't. the on pulmonary fibrosis. T the ptwxerci'e rate in me first-degree linear exagget to the preexerei'C rate w; glass lung-field markings). F.4BEE 3 3 .-- Helot loo oi Averts*re>Mrat<ryr.*re -timteirnur'tVte-\?tr*raftv^im,i'e-_eern._e.ev._x.m.a_.mi.W.in.__.e._d.. I able 34.-- Jntiuenct of anti Arer Number of men Hate itef.ire e\er Hate after e\m* Kate after These data v ere not included in Pat i i provide no means for rend is slight it may be chest girth decreases with r pulmonary fibrosis. tii / exposure in mate ...v * , cxpo-ure, million partuk- y.xirs i 25 to 49 1 5to 99 Ovt*fhi, 2,75 33.9<3I 11 34.179 2.3* 34 44 lung-JUld markings in male l Lunc-fifM m arkings SMi.n.i-l,- Fir>i!Tfwirr. !iint'ar *1 nr..,,fU.-par.un.i 2*2 2 V! S4.TI'T,li .iji.'j at with advancing age. )C'tos-exp(wed men than been so exposed. >tl of t 'lt llf ,< <n<r!.- hm <1 r<t . l u 't K\p. `Juro-i.i-U-tm? Averaiif dn.-t v\ Xumu-rof nit-n in ig.* Avfn*' cbr-r -i- pwMon pao.s.vn Inch** 3,2,5 3 24 3. 11 22.M.5 2.90 laeht ? 9 165 im* 47 2 55 M2 2J3<5> of limited respiratory fossae are conspicuous; ncreased; the substemal : or loss of subcutaneous ` muscles of respiration r4 f1 t 65 may appear to be hypertrophied. In other words, the general appearance of the chest is that of fibroid phthisis plus emphysema. Yniong the conditions that may reduce chest expansion are pleural adhesions and the relative inelasticity of fibrotic lung tissue. R E s I 'U iA fO H Y K . U E The direct effect of pulmonary fibrosis on respiratory rate may be seen in table >:>. Before the exercise test the respiratory rate of males with ground-glass lung-field markings was higher, but not significantly so, than the respiratory rate of males with first degree linear exaggera tion of pulmonic markings. The exercise test consisted of having the subject stand with one foot on a box 14 inches high and to raise his other foot t" the level of the top of the box 2d times in :fii seconds. The respiratory movements were counted during a la-second period precedin'.' the test, during a Id-second period immediately alter exer cise. and durimr a ld-second period 2 minutes after the test. Exercise raised the respiratory rate of all four groups of men, hut the rise in respiratory rate wa- dependent upon the degree pf pulmonary fibrosis, the men with gnmnd-gia-s lung-field marking- being affected most. After 2 minutes' rest, the fall in respiratory rate was again dependent on puhimnary fibro-is. The respiratory rate returned most closely to the preexen i-e rate in men with normal pulmonic markings or with first-degree linear exaggeration of lung-field markings. Ihe return to the preexereisp rate was slower in men with ashestosis .ground- glass hm_'-fi>-i,i marking-1. T a ble :C5.-- .. *piu,/ury rub l'ii<g-f.'l't mivkingi in null* aebftus *< AV l.nmr `Iv-fot* -TMt.r.-l* Xurr.Vr* *' ............. PA*^`-e-rrter '*v\rrtT'-*................................-................................... 2 nunute> .i*r exert,'e........................ 2*'2 is 45~H 17 i *--- U ,,* 41-- ,. w7 ti ij-stt y * 21,4*- . 12 31 -H 22--0. **m 2s. M --l fks 23 3 7 - ,7a 21 ut 21 21 T a b le 34.-- l u f u r n c * of auihraco^sdicnsts m tin n t p t r f i f o n j rntf oj antfirnctU wttor$ 1 Average F.xju^cd to du>?. e^en* Amhraco- rtally normal Number of wen examined. Rate bvfure e\erc"se........... 1'. iW4 75=fc0.m Rate after exercise,............ .. Rate after re*>t__ L............ . y2.2i.. (A*=g 73-- .07 . os 616 20 a20n 3t e1h^se0..,000122f. i T he^ data were not included in Public Health Bulletin Xu. 221, ifttfi iiVirA 66 Similar relation- oro found in a study of anthracite miners, lu men with anthrnco--ilno-i- the respiratory rate was definitely higher thun in essentially normal men before exercise, after exercise, and after rest. CLUBBING OF FINGERS AND CURVING OF NAILS Many asbestos-exposed workers, particularly those with long dust exposures, had a deformity of the fingernails. The torminal phalanges may heoome so bulbous that the finger resembles the end of a drum stick. a condition conveniently described by the term elubhed fingers. 1`sually it is accompanied by a downward curving of the cm! of the nail. The a(feet ion is almost always bilaterally symmetrical and often involves the toes as well as the fingers. It is common in pulmonary tuberculins. In hr< nchic< tasis. empyema, and congenital heart disease it may he seen iri its most exaggerated form. meh exaggeruthm. however, was comparatively rare in this study. In a study of 2.711 (.' li anthracite workers, the deformity, regardlt-- of degree, was observed in about a third of the workers having unriiraco-dficosis, but wa- pre-eiit in mily 4 percent of the eontrois. The real signfir canoe of the allVetion ha- not been determined. Xm'ri- and Landis 0>2 -tata that in all probability it is a manifestation of Ioug.-tanding toxemia asMieinted with pbthi-i- or hroehieeta-i-. Tie- bronehieetatle and ompby-eli.atou- rhaifge.- noted in the a-be-totie lung at autiipsx probably aeeniiut tn a great extent for the <eriaivnee of the change in the worker- with a-he-tosis. T able 3.V --A tntib* / oh/ p* >r* <' (t/ Cm>* ! r Wj* ' ' A . spit/-* / //<>' * > *>- '/ h j I /IiQ-p Ui ft '7', c !bh*<]fing* n Luns-fieM nurk : 2- j . f J j 1 , ! Heart defects w general. They w pulmonary fibrosi f f *` ' J* ,# A. * * 1 %] 4- 0. ' ' jHMru 1 in -iiu r-itig f 5,' r , - '`0',nn*i-'ieur**e F-r-** V-t***- } f<` it ~ * .. . -- Ta ^ T.tn!....... N',r;- ,1 ... _ Tmi. mm..... ............... T ---- . -- - . : -r ivr- NHuner Por* eenr Nun.her per* ve:.* Nur - wPerr-: It ?N Pm ,Mt 'i M V1 stl s \ JJ 31 HI h 0 ii u -, 2 ,, P> 4 m 211 2?Vi tl **3 37t.4 2' Five controls (0 percent) had curving of the nail- This percentage ! Ivas much higher 19.2s in the asbestos-exposed group. Thirty-nine percent of the workers with first- or second-degree grmmd-glassg lung-field markings had this condition. HEART DEFECTS Taking age into consideration, blood pressure values conformed closely to the values found on examination of 10,143 male industrial workers ). C 0 Fig ur e 39 --P h o to En la rg ed S30 T r Ru l e d in u n i t s c Bo d y cussed, but no sit 'tudy (including asbestos workers, had normal hear heart impairment fin iriffiftfiM jm M * racite miners. In s definitely higher fter exercise, and AILS >se with long dust terminal phalanges lie end of a druru in clubbed fingers, the end of the nail. Metrical and often mon in pulmonary congenital heart a. Such exaggerady. In a study of gardiens of degree, g anthraco-silicosis. The real -dgutfiXorris and Lamlis on of long-standing s. The h r o tie h ie c asho-totic lung at .e occurrence of the H'hn iifitl cluhhf-<l fihQcr* 67 Heart defects were no more numerous than in industrial groups in general. They were tabulated in relation to dust exposure and pulmonary fibrosis in the same way as the impairments just dis- Ht* Sec'`nl-<iesrm* rvuu'l Tti er- N'tmt- Per* nt rent HM Ptt u 2104 ` * n 5 64 7 09 m Xi 251 3 Is. Tiiis percentage group. Thirty-nine degree ground-glass e values conformed 1,14d male industrial Fi g u r e 39 --p h o t o m i c r o g r a p h s o f a s s e s t o s i s Bo d . e s Fo u n d in S p u t u m . En l a r g e d 530 T i m e s Ex c e p t E w h ic h i s En l a r g e d 310 T i m e s , a Sc a l e . soRu l e d in u n i t s o f Microns. Has seen d raw n beside each a sse st o sis Bo d y cussed, but no simple relationships could be found. A careful cardiac study (including electrocardiograms') was made on one group of asbestos 'v.ekers. Matty workers with advanced cases of asbestosis had mutual hearts and no evidence was found which would relate hiart impairments to asbestos dust -exposure. ( mmm WSWCPSH'wiw I<.nu, jsal (8 . ASBfcSTQS CORNS Asbestos corns are wartlike callosities, 1 m m to 5 mm in size, usually located on tbe palmar surfaces of hands or fingers and ocoa>ionall> on sole- of t<h*t nr **;i tlo* !*`^< fig. 39/'. Their presence "U the palmar ~uria<v- t;(.lunula i- e x p la in e d by the fact that w-users. <ui br.-aning threads uf a-be-t.-, force tiny slivers of asbestos under th<> skin where it initiates a foreign body response. This .'potise s characterized by hyperplasia and hyperkera tization. Tabic 3; -how* that the occupations in which asbestos corns are :::<'~t common ate rules in which workers test the tension of movinsr dorads with their tinkers, nr in which they ate obliged to break reads with their hands or to knot threads together. i ,t l ' b . r.c n-),n "re */mjfm/ > 0 >u,, r , e l ' i x x i f i i ' l hi, `' i'reij!,,t|un Numu*r entf-k>yH X'lnti^r %'ih Pm-en? t rr> with f + n s t.' -i' *.v* iru W :* IT rt-v^*: *,y d.Hh trae't werker? Microscopically. Dewirtz 10 >states that the corns present a picture of dow chronic local irritation. The homy and Malpighian strata of the skin are increased. Round-cell infiltration is noted particularly it; the papillary layer of the dermis. Asbestos fibers or crystals are also seen anti they are regarded by Dewirtz as the agent responsible for the thickening of the rete murosum, basal layers, and the giant- tntmation. (.linyne >10 i has also found asbestos fiber in the corns, but noted that asbestosis bodies of the type observed in asbestotie lungs and sputum were absent. The workers have themselves called these little tumors "asbestos corns," or asbestos warts. Xot in frequently the corns become very tender, particularly when pressure is applied to them in the course of handling tools or machinery. On account of tbe pain, tbe worker* will attempt to remove the spicule of mineral with a pen knife or some other sharp instrument. Should the fiber be incompletely removed, it recurs with greater livperplasia because of the added tra that every bit of fiber Only occasionally, houe\ Dewirtz (10) advises con r Unusual structures ha\ i histological study of the bestosis but no detailed < (it) and McDonald i22i the conditions muter w, papers apparently awaker ; on asbestosis bodies appe; i The following review from complete, but it wii ; that has been put mi re< | show that these bodies or asbestos fiber. The c o re surrounded by protein ! formed only in the lungs. (36), suggesting that they tract. They have not he* form on the hands of ashes of experimental animals ( Dardner i~>7) found the "1 but for some unaerountab larly exposed rabbits. T) I the sputum of patients wit , and smith -is), the sputum even in well-estublishei ca DO) has been suggested as Asbestosis bodies are vari , Characteristically, they art j with bulbous entls which g ' Occasionally, a forked or V i `n figure 39 is encountered. the center of figure 39 was I *Putwn samples from 281 j in sections of lung tissue. I say, ` R e suggest that the findings of a i sputum as here described is a i I whether by a process of simple case, or as a result of secondary t al,le <>conclude that there is als is *s, 1 mxn to 5 nun in size >f hands or fingers and occaw fig. 39a). Their presence explained by the fact that force tiny slivers of asbestos reign body response. This i^ia and hyperkeratization, n which asbestos corns are 5 test the tension of moving they are obliged to break ids together. hail asbestos corns, classified t>:i Number Ncw'uoiwmrinfh.b."heir wPitmb-u^,nrrm rIil'l HWi\* fi I! 7^ l II IAwr* 4 <4 0 4 Iri 00M 17 0n 4s> 42 49 >' 29 117* y ri it it 0 n Is l i the corns present a picture ny and Malpighian strata ration is noted particularly estos fibers or crystals are tz as the agent responsible a.al layers, and the giantasbestos fiber in the corns, pe observed in asbestotic ers have themselves called asbestos wart-'. \ `.;t ju. Atrtieuisily when pressure g tools or machinery. On upt to remove the spicule hatp instrument. Should ' with greater hyperplasia ' , ' j i ! " 69 because of the added trauma. Most of the workers so afflicted insist that every bit of fiber must be removed before the corn is cured. Only <'ra'ionai;y. h<>we\cr, is medical relief -eight, and in such cases Dewirtz (10) advises complete surgical removal. LABORATORY FI.NDI.VGS A 'B K 'T k ' I s fi'U jlF ' Unusual structures have been observed by several investigators on histological study of the lung tissue of men who had died from ashestosis but no detailed description appeared until 1927 when Cooke i0) and McDonald >22) published photomicrographs and discussed the conditions under which asbestosis bodies are formed. Their papers apparently awakened interest in the subject and several papers on asbestosis bodies appeared soon afterward. The following review of the literature on asbestosis bodies is far from complete, but it will serve to indicate the kind of information that has been pur on record thus far. There is good evidence to show that these bodies originate as a cellular response to an inhaled asbestos fiber. The core of the body is ait asbestos fiber which' is surrounded by protein deposits. Apparently asbestosis bodies are formed only in the lungs. They have been recovered from the feces (36), suggesting that they pass unchanged through the gastrointestinal tract. They have not been demonstrated in the asbestos corns which form on the baud' of asbestos workers 10, 57a . nor in the peritoneum of experimental a n i m a l s 57' into which the dust has been injected. Gardner i571 found the "bodies" in the lungs yf dusted guinea pigs, hut for some unaccountable reason found them to he sparse in simi larly expose,! r a b b i t s The bodies can Usually be demonstrated in the sputum of patients with asbestosis, although, according to Lvneli and Smith 3s . the ~putum may he negative on repeated examinations even in well-established cases. For ea-es of this type, lung puncture (40) has been suggested n~ a diagnostic procedure. Asbestosis bodies are variable in form tig. 39u) and in size (table 37). Characteristically, they are slender, elongated, segmented structures with bulbous ends which give them a dumbbell or drumstick shape. Occasionally, a forked or Y-shaped body such as the one marked II in figure 39 is encountered. A rosette such as the one illustrated in the center of figure 39 was observed only once in the examination of putum samples from 2$1 persons. Rosettes, however, are common in sections of lung tissue. Stewart, Tatersall, and Haddow (41) say, We suggest that the rifidiritr-- of a larse clump or clumps of asbestosis bodies in the >putum as here described is a clear indication of disintegration of lung tissue, whether by a process of simple suppurative broncho-pneumonia, as in our first case, or as a result "f -ecor.darv tub^rculoU' irfeormn. In either case it is reason- a b i,. t.> Ci,r.cbid>- t! a t t:.< re > a.-.. .1 -m m . m rK ! j . . - h . - t . - i s , ` 70 \ i s 4 The asbe ...nations i ,.|n'StO^S l) -:,niplf* of s had been ei average Because lie a-hestosis s diagnosis from anotli an average Except for lung fields In sever: fiber may 1 ments ism golden yell tlves ontin reaction i v AsbestoSince they size is imp that may a-bestosimens was body was ment~ apf Table 37. I.eJU ry ' '! <<';! no \ .Mmot<S,);<.4-. H i v t .4^"1i*..i.4i`y*.. <;' atm*"' C C R -v ON "T H _ \ 'B O P 2 - V a EvPwO^eO Z - --tom an -ssS*os ~=:x"' wEpactov p*=?evrooSuY " C O " O'-. `O / . 0 0 _ E N ~ V . - _ V L u 3 c K ' D G R A P H ia wx i*|iij*eiie<iniT. }v<ir'rt't'i'fru' i i jcf'i 'mi i Ih t -.Jnml hrillm the hml-t- in IAN EMPLOYED 4 r y . P r e v io u sl y s. Photoorapk 71 The asbestosis bodies illustrated in figure 39 show some of the variations in size and shape seen in sputum smears. Five of these asbestosis bodies `*1. C, D, Li, K i were found on the same slide. This | ;,nipl<* .tf -purun \v.;- obtained from a 37-year-old mule spinner who had been employed m the asbe*tos iudu-try for 7 _ years, expo-ed to l an average dust coneentration of S million particles per cubic foot. J Beeau-e he made no eomphiint of any ot the major symptom* ot t~be~to*i* and *" hi- ! m-_T fields were *-<tnl~lei:foe linear, no diagnosis of a*be*ro*i* wa~ made. The bodies labeled d and / / emtio from another m'.le *: inner, a 37-yenr-old man employed 2b years in * an average du-t oom-.-atratioii of 7.9 million particles per cubic foot. Except for a cough he had none of the symptoms of asbestosis and bis lumr fields were ow-i.tially normal. In several photomicrographs of the "a*besti*i* body, the asbestos fiber may be seen dearly. The bodies are somewhat fragile, and frag ments such 5l* L in fig. 39 often oceur. f'ti'tained specimen* are * golden yellow or golden brown. T h e y do mt s ta in w ith th e aniline dyes o rd in a rily u*el in hi~tology. b u t th e y sta in bine (pnissian-blue r e a c t i o n when treat-! w ith potassium ferr'yanide.' > Asbestosis hoiie* a n be detuon*rratel on sectioning lung tissue, iince tbev arise as a tissue reaction to an inhaled asbestos fiber, their size is im portant because it indicate* the length of the asbestos libers that m ay reach the lungs. The greatest length of the first lb's ashcstosj^ bodies found lurirur th e stm ly of p repared sptitum -peei- mens w a s mea'Ure! on amera-liH-nla rawimr*. E v e r y a~be*tosis Viody w a s m ea-ured a n d the frequency ili-trih u th m of these tnea-ure- tuents appear* below T a b l e 3 7 . -- F " ff **>/ .* *jh n' th*; U h t y i ' >' jir^t ftI.h'i It- ' ft'it>tIII ' to-ij-' /stn Length m: !.*e<.-*r._fdil . Len.rh :n tmTon* N'nnilte*r >f e*of t *e ler.gT h >J<ee*hed T**al mea>ured .. 'IMf' mu 'JI*V*......................................................................... It o, i'- l........................... 4t r,> f t ...................... V u>:`,t................................. mT-ttm*iB'- -h *o1I11`2i*iftf<,ttriioo.!**q1l!*.. l (t Mi!Hne\i . 47, method wu* u*ed in the i repent r-rudy of thde-u ?**I diesm sputum. A sample tf sputum ii d.je>red with an "-pi si \<-l .me of (ftnter.7r.ue-l innformm. yen'? 'lued at moderate -^eed. the nntifornr.n :* p.pered urL and rep] ard v :he folio* .rv rr:.\ture: 2pe^et-T j urn. fenv-cyanide. 1 part. 1 fe w e r I'-yd'* "M-.r.c o -I r>; .r-. 1 *uN* i> - *.sen m l allowed **,.; for r* l hour, ft i$ then recent n* fuced ,nd the mater;] n.<<u::>d as a wet prep.m nun. '\.*h *;. > trvhni'pie the asbestos,* todies are colored bnli.ant blue. If without treatment with pm ferrooyautde and hydrochloric acid, the bodies are tmlden >eUn\v m color. 4.*U62-- dS-------*y mm <^w^ifiiaiTiHlnWi-nua:' wtrfMjwHfc The asbestos bodies ranged in length from 10 to 128 microns; their j The ineidett average length was 35.1 microns. After completing this series, | exposure. routine measurements were discontinued since tins seemed to be a large enough sample to indicate the sizes of asbestosis bodies most I , T a ble 38 -- frequently found. Tbe largest body found in subsequent study of ; sputum specimens measured 184 microns in length. There seems to { he no completely satisfactory explanation for the absence of asbestosis bodies measuring less than 10 microns in length. Asbestos appears to differ from other pneumoconiosis-producing dusts with respect to the size of the largest particle that may reach the lungs. The largest reported upper limit of size for rock dust in s the gold mines of South Africa and in the granite (48) and anthracite (11) industries in this country is 14 microns. The data of table 37 are in harmony with a concept that has been gaining support in recent years, namely, that particles beyond 10 microns in size reach the alveoli. Measurements indicate that the diameter of air sacs may be from 150 to 3uo microns in adults, or, in other words, of such a size that ashestos fiber or resulting asbestosis bodies may be readily accommodated. Asbestosis bodies were found more frequently in tbe sputum of persons who complained of a persistent cough than in the sputum of persons without a cough. This is a reasonable finding, since the act of coughing tends to raise materials front the lungs. Half of the 5b people who complained of dyspnoea had asbestosis bodies in their sputum. Less than a fifth of the 225 asbestos-exposed people who did not make a complaint of dyspnoea had asbestosis bodies in their sputum. Almost the same relationship holds for a complaint of cough. Each person to bring a 24-1 that purpose, i content was do the 41(1 persons analyses areav from the result expose them to Albumin was in the urine of ; negro males te contained sugu higher than in ( for comparison found in indust Asbestosis bodies were found in the sputum of 4(1.9 percent of persons whose condition was diagnosed as asbestosis. A much smaller T ai proportion, 24.3 percent, of essentially normal asbestos-exposed persons had asbestosis bodies in their sputum. Thus, it appears that rrinarj the presence of asbestosis bodies is evidence of exposure to asbestos du>t, but it is mu necessarily a diu_ io-ti<- -iim of asbestosis. Asbes tosis bodies were found in the sputum of persons who had been exposed tit a-boto- du<t for as short a time as 3 months. Of the workers MiUftr-tnjs siiti i- r T Miliii.*rtirn< iliea per d. NumU-r ....... employee. i -.- than 1 year. 22.5 percent had asbestosis bodies in their sp-.T.in A larger percentage, 5s percent, of workers employed more than >year- had these bodies in their sputum. In evaluating these percentages it must be remembered that they are ba-ed on the exami nation of a single sputum specimen trom each indj\id::,d. If -event! specimens could have been collected and examined, the percentage of persons with a s b e s to s is bodies would almost certainly be much higher. | t ; Silica was pi per 100 cc. . persons whose < that there was dust !which co centration of u No asbestosis bodies were found in sputum samples from any of tbe 7(1 persons tested who were not exposed to asbestos dust. 7The colorimetric pro molyhdk* acid compie* amount of silica present :8 microns; their ing tills series, seemed to be a >sis bodies most ?quent study of There seems to nee of asbestosis niosis-producing that may reach for rock dust in ) and anthracite lata of table 37 ling support in ns in size reach ?ter of air sacs r words, of such may be readily the sputum of i the sputum of g, since the act s. Half of the >bodies in their people who did bodies in their i complaint of b'.O percent of A much smaller sbestos-exposed it appears that ure to asbestos `stosis. Asbesid been exposed Of the workers bodies in their employed more valuating these 1on the examiuxl. If several e percentage of >emuch higher. Yom any of the 73 The incidence of asbestosis bodies increased with increasing dust exposure. Table 38 -- Relation of dust concentration to occurrence of asbestosis bodies ttVibred expo-mre Namher Number Percent with :u>be>- w;rh acibes- T * . * ; -e-i . * 5' ,.1e. < . ........ . .. 2* I A t* ............. . .* 59 74 ~ 27.0 2, 21 '* 23 i; ; U. 1 R E S U L T S O F T E > T S ON* U R I N E Each person employed in the three asbestos plants studied was n-ked to bring a 24-hour sample of urine in a metal container provided for that purpose. In addition to the standard clinical tests, the silica content was determined by the method of King and Dolan <.591.- Of the 4 lt> persons expo-ed to asbestos dust at the time of the study, urine analyses are available for 403, and these results have beeq kept separate from the results of urine tests made on 07 persons whose work did not expose them to asbestos dust. Albumin was found in the urine of 10 of the 24$ white males tested; in the urine of 10 of the 98 white females; and in the nine of 3 of the 57 negro males tested. Only one sample of urine (from a white male) contained sugar (Benedict's test). These rates of incidence are no higher than in the control-; and, insofar as published data are available for comparison, they seem to be no higher than the rates generally found in industrial populations. T a ble 39 -- R iln H o n of u rin a ry silica to *1u*t ixi^fSore Urinary5k- Control* Dust e*po*ure. million panid*? per out-a- Unit 0 to 49 * t.9i* Ito lv V <*.-r 21 Milligram* Uica |*T l*ec....... 3.11**0,13 3 .V*H. 13 2. Milligram* -ahr* j*r <i ?......... 30.45. 14 30.-52=1.20 3o, Number tv*TKl..,.................... S3 v* <2l>* lo* 2>2. **rrO. 47*1 37U7* 371..4V4**=0L.1304 lf*u Silica was present in concentrations ranging from 0.7 to 11.1 mg per 100 cc. Average urinary silica concentrations for groups of persons whose dust exposure varied widely (table 39) do not indicate that there was any simple relation between the exposure to asbestos dust (which consists of hydrated magnesium silicate i and the con centration of urinary silica. Rather, it appears that the values for 7The colorimetric procedure for the determination of silica m the urine consists m the production of a silico- niolybdie acid complex which is reduced to p v * a blue color, the depth of color being ptfirorticnal to the amount of silica present. * | 74 dust-exposed person? fluctuate above an} below the value for the controls. TSte total daily silica output was calculated by multiplying silica concentration by the volume of urine excreted in 24 hours; these values (table 3b) also show no simple relation to dust exposure. Urinary silica analyses are available for two other groups of people whose diet resembled that of asbestos workers m consisting largelv of vegetables. The urine of seven male college students living in the same city averaged 2.6 mg per 100 cc (based on single specimens, not 24-hour samples). An earlier survey of an industrial plant in Tennessee made by the Public Health Service v showed that the daily silica output averaged 20.S9 --0-20 mg, a value very close to the mean silica output of nonexjHised asbestos workers. Diet plays an important part in influencing urinary silica eonecu truth m as King and Dolan (59) have demonstrated on experimental animals. A predominantly vegetable diet, with its high silica content, lead- to a high urinary silica output. It may he that the dietary intake of silica was so great as to totally ma-k any possible effect of -ilicate absorption through tin* lungs, in .any ease, the phenomemm reported by King and Dolan for gohl miners <.5!H and by the Public Health Service (.51 ! for anthracite miners, namely, a higher silica excretion in men exposal to -Hint du-t than in nonexpo-ial controls, does not appear here. The urinary -iliea concentration of the asbestos workers is higher than that reported for the two occupational groups just mentioned, and this appears to he largely duetodietary inferences. Silica eoneentnitum increased with increasing specific gravity. The silica content is, of course, to* low to influence the specific gravity directly. Instead, it app`ars that the two values may vary concomitantly, ami that the drinking of large quantities of water, for instance, w*ttld lower both the specific gravity of the urine sub sequently excr'tcl and its silica content as well. j | : i * , \ ' (kcnimitOtal' is important t have resulted disease proves signs and -yi mainly in let when the oee dust anl no 1) X -r a y j<h<h characteristic of the lung fiel roentgenogra | that might oo for the signs character of heart shadow who have rej be referred 1 X-ray exatni individual w these limlins. means of let* tion can ofte pectoral mm single plate This pos-ibi! tion of `In*' muscles slim films should presence of 1 T \ k i.e 40.--- Htlnl'ttit nf Jim content ot u r u t>- to uptcific gravity ing an X-ra; v,Helth.;t5 sihuavoT.tent Nsui:m'iUp*l*er?of , fleet nccordi' classes: first markings or I* ! 11it1*`J."1t?rtoI-.' 11!``It2M''pk/tt..,, . t e r l H.'H . , M u 2.21*1j<1*:*< n .. /.w ,. 23 There is g 1 sucee--ive - pa-> under T H K D t4< ;N O S IS O F A SH K STO SIS In preceding sections of this bulletin the signs and symptoms o f t-U-to-i- have been treated one sit a time or two at a time in order to -how their relationship to dust exposure. In this and the two follow ing -ecfioti- the symptom "omplex of a.-bestosi- and its relation to dust exposure will be discussed. -aid. the gi the lung lie in which tin marking- w the type of lung field. Unpublished data. * * I i l l f f i W i i i m i i i nil iii *tum mm -maplTir the value for the ted hv mult iplyim_r reted in 24 htmis; n to dust exposure, er groups of people t consisting largely udeuts living in the ngle specimens, not -trial plant in Tenwed that the daily y close to the mean urinary silica rou ted on experimental : high silica content, >e that the dietary tv possible effect of a, the phenomenon >and hy the Public ely, a higher silica onexposed controls, ition of the asbestos occupational groups odietary differences. -f specific rarity, fluence the '[iccific `O values may vary pumtities of water, y of the urine sub- ; i ; ' <p*Wic gravity wt i $ s and symptoms of o at a time in order n this and the two sis and its relation to 75 Occupational Atdo-?/.--In establishing a diagnosis of asbestosis, it is important to exclude the pos-ubilitv that the observed effects may have rc'iilfi'd fiorn inbaiatiou oi itmiiicr kind of du-t or -i>mc o f f er disease process. An earl" case of >ili,-ois. or instance, might pre-rut sitrns and symptoms which wotiid differ from those of asbestosis mainlc in degree. A diagnosis of asbestosis should be made only when the occupational hototv -hows previous exposure to asbestos dust and no heavy exposure to other siliceous dust. X-ray fin<ti,j.*.--Although the _ooun<l-uiass markings that are so characteristic of asbestosis-are usually localized in the bu-nl portions of the lung fields, nevertheless all regions of the chest must be examined roentgenographically in order to detect signs of other disease processes that might complicate diagnosis. It is important, of course, to look for the signs of pulmonary tuberculosis. The distribution and the character of lung-field markings are significant. Shagginess of the heart shadow (see p. .3dj has been mentioned by several physicians who have reported cases of asbestosis. The pliv-ical findings should be referred to whenever cardiac enlargement i- found during the X-ray examination. A consideration of the chest shape of the individual will sometimes modify the interpretation of certain of these findings. Fluoroscopic examination is. of course, the best means of detecting diaphragmatic impairments, but valuable informa tion can often be gained from a study of a chest X-ray film. Heavy pectoral muscles may ea-t an X-ray shadow which resembles in a single plate the shadow cast by tlie increased fibrosis in the bases. This possibility must alwavs be kept in mind during the examina tion of elie-t X-ray films. Notes on the thiekne-s of the chest muscles should he entered on the physical examination form, or stereo films should be made in order to obviate this source of error. The presence of bronchiectasis caused difficulty in diagnosing one ease. Classification >,/' lnn<j-fol'l arkmii*.-- In this study, after examin ing an X-ray film and before making a diagnosis, the film was classi fied according to the nature and degree of fibrosis into one of four classes; first- or second-degree linear exaggeration of the lung-field markings or first- or second-degree ground-glass lung-field markings. There is good reason to believe that these four classes represent successive stages through which a typical case of asbestosis would pass under continuous exposure to asbestos dust. Since, as has been said, the ground-glass markings appear first in the basal portions of the lung fields, it follows that any given chest film might have areas in which the markings were ground glass uid other areas in which the markings were linear. Usually the basis of classification has been the type of marking that predominates in the lower third oP tip* visible lung field. ' * FIRST DEGREE LINEAR t SECOND DEGREE LINEAR FIRST DEGREE GROUND GLASS SECOND ' DEGREE GROUND GLASS *s F'ig u r e 4 0 .-- p o r t i o n s o f C h e s t x - R a y f IL M S V .h .CH ILLU STRA TE TH E SU C C ES- s i v e C h a n g e s B r o u g h t a b o u t b y LONS-CONTINUEO in h a l a t io n o f a sbesto s Du st. i In order to show possible if the entire of classification. tigu Symptom*.--Dysj chest, weakness, dec and silicosis. It is poss silicosis by history o I bodies in the spilt un X-rav markings. W t data show that tliey evidencc of exposure Smith (3S) reported vaneed case. The i been reported to be Xoadvanced case in the present stud asbestosis cases \\iii> of other disease pro plicated British east are usually reportet and usually have a Plates made Iron to o l. Roentgenog showing advanced s of comparison. Ini an abstract from tl panics the X-ray. remembered that characteristic of as and reproduce. It is not quite as genet Cooke ha* reported so:*-* m'TpholofitHUy from a^*"**.' { inI 'ruaMMMWMlillMfc. UliigiBiiMil FIRST DEGREE LINEAR SECOND DEGREE LINEAR FIRST DEGREE GROUND GLASS SECOND DEGREE GROUND GLASS STRATE THE SUCCES SO INHALATION OE Ii In order to show these markin':? on a larger scale than would be possible if the entire film were reproduced and to illustrate this system of classification, figure 40 has been prepared. Dyspnoea, cough, blood-tinged -putum. pain in the ` chest, weakness, decreased chest expansion, curving of the finger nails . and adventitious chest sounds are symptoms which also occur in , silicosis. |i i-.s-ihie to differentiate pulmonary a^be*tosis front | siite**~is by history of exposure to asbestos, the presence of asbestosis1' bodies in the sputum orlun^s, and by the tyo,. and distribution of the X-ray markings. With reference ro a-bcsi -,- bodies in thesputum, the data show that they may appear alter 3 mouth''expo-m e. They show evidence of exposure to dust, hut not established disease. Lynch and Smith (3S) reported difficulty in demonstrating the bodies in an ad vanced case. The presence of rosettes as illustrated in figure 30 has been reported to he of greater diagnostic significance. Xo advanced cases of ashe'tosL of the bed-ridden type were observed | in the present study. Reports (13. 2. 2<i. 32) of fatal American asbestosis cases which were relatively uncomplicated by the presence of other disease processes are essentially similar to reports of uncom plicated British cases ifi. 14. 34. 35). Patients in the terminal stage are usually reported to he emaciated, markedly dyspnoeic, cyanotic, and usually have a severe cough with wiry mucoid sputum. REPRESENTATIVE CASE HISTORIES Plates made from representative X-ray films appear as figures 41 to 51. Roentgenograms of a normal chest (figure 4tj and of a chest 1 showing advanced silicosis (figure 421have been included for purposes of comparison. In figures 43 to 51 u hieh represent nsbestotic patients, an abstract from the case history and physical examination accom panies the X-ray. In viewing these roentgenograms it should be remembered that the ground-glass lung-field markings that are characteristic of asbestosis are exceedingly difficult to photograph and reproduce. It will be noted that the distribution of the shadows is not quite as general as in silicosis. ` Cooke ba>*reporte! -onieu h.it nular bodies in the sputum of anthracite miners, btic they seem to dititer morphologically from asbestos* bodies. t I a irMiMiftiili 78 i 1 t i i fu G o F te !" -- N o r m a l P ul..'ONt c M a r k i n g s ^ h i' e V a l e AGE 2 3 . .V o te ttie linear ty|ie of pulmonic marking- u~:ahy >:.e c ie -t roentgor.o- cram of an a'trii& - tndu-trial worker not expo-ed to a b ;-t hazard. Tlii* m an hud worked d \v ar- in the decorating departm ent ..{ a lottery and 2 y ea r' at general outdoor labor. f F lO U tE 4: :ma. <U'o :' a-dx-'to' H u . i i)li| i P ,fP i|wl.|!>"' .... .n * f r f p " ....................................... ""fi n m r i r i . . t i p pp f T ' ` -- p * p * * " * w fi Hi'-*' i i I 79 A i M a l e . Ag e 2 3 . i the client ruetitgenot hazard. This man tfterv and 2 years at M FIGURE 4 2 .--SILICOTIC PULMONIC MARKINGS. WHITE MALE. AGE S t. N ote eoar~e nodular appearance, w ith begiuuiiiK coalescence of these shadow? in th e upr>er half of the loft. M oderate emphy-emu both ba-es and slight medias tinal distortion. Nodular markings of the type here shown were not noted in asbestos employees. r mm tmmm MwifiMkAM faaimiir m r iii*OWi,OiiC.rli^fi ,Wir% K> % \ 4 i' L ... F ig J R E 4 3 . -- EARU.V A S B E S T O S iS . i'.H lT E M A L E A G E 2 3 Oecupulfinal i ,stt>r<j.--Carder ia-!iv?ti- . 4 . ><ar-: !.'!.iu~ty trade?. .V. years. ' I ' x y o o i t r f .-- '! 3o.3 million particle-j>er cubic foot. if' Million p article t : : 1 *9. No -iitn.tK a- r n a-t itiedieu! find.: i - nr c />. -- 1-- r ..t-.. -V - .< - t-. t - n .'i'i H i 's j h t . ` T 't in c h e s ; we.gnt. 143 p .: i? Hat 1 r . . 2 ' "- X - change lti fremitus, bream sounds, or . .- - !>? 1 Is Pulse rate, 96, 120. and Mt 'n-f-.- , . - -r .- td 'e r r.M 'tne.a! exercise. I'ri: ' 2 - r r . v . . s -> . Routine urinalysis uegat.'.e; -pee,!tc strut,ty 1 .022. X-ray.'--First-degree ground-glass appearance 't qu.te obliterating the coarse lin-ar marking-. Xote the fine, close-set reticular markings just off each hilum and the anuv- remaining quite clear. i i . --K.irlj a-!,.-.'?,.-;, a t-i oi t sym pt-.;:,- t (im plicated b y h y p erten siv e h eart di-ease. I / FlGU Ocritiniial I t (asbesto- , 1 vear EshniaU tl ''ift f o o t . do MllllOl tnt il "'ill.-- Bilateral puoume Camihli "f<.--S l J l Iistttll lJill" . itches; weight. 14 Pul-e rate. s.3. ! Indore, mituediat mediate ehe-t ty si-te'.it eraekling u r,- t >! tt'it c \ U-iA-.'Jo; li 24 21.0 II h< "t. "i"i -- moderately no re X -ra'j ,-- Note ating the linear Generalized fibm Diagnosis.-- A ; fjwt <4 i i --".a-,'" ?ain<WWMi*nfc<-mm 81 | - -j rfAC-e. AGE 29. lo -r ncdubuisctvfotroat,dey,b3)lM. riellairosn, iiale. Height, 6 7 '. inches; 2 inches. No chance in pressure, 10S 1 IS. pulse 2 minutes after functional u tput, 31.3 mg>. Routine .lite obliterating the coarse kings ju st off each hilum implicated by hypertensive f Y F ig u re 44.--Early a s b e s t o s i s . Wh it e Maue, a g e 9 . Oo'uimimint! ),/.<,> -- Xluie -p.nner asbestos-, last 15 years; roving atten d an t (asbestosif l year: n-'iidusty tra ies, years. E stunfitf I ii'n.<t .i Weighted average, 10.5 million particles per cubic foot. (.6) Million panicle years. 103.2. Past iiiKlu-id.--.^iirapncl wound right parietal region of head. October 191S. Bilateral pneumotua as a child. Comflaints.--r>l:cht weakness. Physical ejuwitiei.'i.ei.-- Interm ediate build, fairly well nourished. Height, fid's nches; weight, 141 pounds. Che-t expansion, 3 `j inches. Blood pressure, 130 S2. Pulse rate. S3. 12d, and S4. and respiratory rate. U>. 24, anil IS (.respectively before, immediately after, and 2 inmates after functional exercise test. Inter mediate chest type with slight increase in A -P diam eter of chest. Few mmper- sistent crackling rales at right base. Asbestos corn on palm ar surface of left wrist. Slight cyanosis of lips and nails. A dusky red cast to ears. Sputum negative for B. i-l* r-tlmis ami asbestos bodies. I'rin ary silica. 3.(1 mg per 100 cc (24 hours, 21,5 mg . Flmroscoixj.-- M oderate ,2 --* lim itation of diaphragm atic excursion. Hila moderately increased in su e and density. X -ray,-- Note the first-degree grainy or ground-glass appearance, n ot obliter ating th e linear markings, giving general reticular appearance to lung fields. Generalized fibrosis 1 -r. I Diagnosis.-- Asbestosis 2. .* u ..iRjRMia..4taiu>,'n. ' iiliAiiaMrtl! Ii^ n v -r itoiiriwIji.mahMWhhfafc - |s 82 .. i j F igure 45.--m oderately advanced a sb e st o s s . '/.h it s m ale age 46. f f r r . y HUi n r . n l 1 . 'r / - H r- a ! t 1: v u v t r a*!* - - . 7 x a r ~ *' in t ! , s . Pre- \ i'ffi.-h i li Ini', d - l- t \ ?ra*i< i " . <'a ' > 1** \< u r - u - l u m p t . K < f t uni t* >/ .MS , , . -- e W e ; i : : *t -i t \ : i * 1 ^ !: <-\ t r t ;c l s per cubic flM.t f, M . U ' . e ' . a - - . 11' . > i ' l l ' ' i , . . < (HI, 1,1m - ' - T . . i. - , , *, : . . i!<! P. r ^ t. lieD - i >, l u t e ; . : . it i r i . l l i .i i o i ' si; * . i<<r o , t n r - \-r 1H2*: t : ,li.K mucoid stmtum. Sliaht dv-pnoea. 2 t" 3 year- Bli.iid-r.hged -nutum. I 'i -i-i, 'il ./.if.......-- Hf.iii.t. 7i _ : i-i - \\ ^ * ' in Bl ood t>re>- -ure, tub >2. Pui-e rate. 72. ns. an d on; r i - o - . 2 i. 2 "n a- : 2 t "for*-, immediateiV after, and 2 a* - a t '. . t u .i l t n '.a. e\erc.-> test Pa' . ` vu* wletcd only a b o u t half of prescribed exerei-e. Cik--t expansion. 1 ihe'h. - . : r* Piijeviiat rounded. C raeki'hg 'ale- : card over 'i t;. rin g s .>n uu;et nreat utiie, ;f:.if the-e MT-i.t a ' t e r r.. .g:.; 2 ~ i - . r . e d ringer hi-.;'.*; 3.1 ihk -idea p T ldO cc .single sp ecim en 1. FI ................ - I,* :t -ale .it d ap'.iranni iu n v t- m..re freely th a n right: 2 -- limita tion of excur-ion. e-neeiallv "i; r g h t. V- . -- Shiiv. - - i n ! ' ! a : -- g r .n : d-g!a~- a I .!> a r a ' tera!in '.i-U:b linear ! e ii..ir.. : : I' a ;a: * i r . - '.u x!.e a - - <-f Sung I h . i y . -- A-'.i-tii- - 3 a,..derate,\ adxat.ced I f ig u r e 4 6 .--m o d e r a Occupational hstory.-- 4!* vears; idle. 4 '. years Estimated tins! ixposi cubic font, i.fei Million Past rmdtrill. --Intluen (am plat nt*.-- Xorie. Physical isamination.156 pounds. Intermedii over lia-es of lung-. I 'r Sputum not examined. F bonoxCtiji y.--Sll. >\\ed left with first-degree cliff X-ray.--Shows- fir-t-d Marking-. It illu-trateand tile tetnlenvy to be n Diagnosis.-- A sbe-to-i- ^5 i j, MPipmLI4i.l! |pM--l'*W''<m'!'IjM Iiiwflil 83 1 . Wh it e m a c e , a g e as. 7 yours 3 months. Preours as farmer. S million particles per cui'ie lit. March 1020. ar- productive thick mucoid icd sputum. it. Hi pounds. B W d pro rate. 2d, 2 S. and 24 i of. to. \erei.~e testi. Patient o m \!iunsion, 1 inch. Shoulders :h longs on quiet breatkuig. Us; 3.1 mg silica [ht .00 re freely than right; 2 - Uriiitu- :tnee obliterating usual linear f fibrosis in the bases of lung f i g u r e 45 --m o d e r a t e l y a d v a n c e d a s s e s t o s i s . W hit e Ma le , a g e aq. Occ>tpiO-',n,il i, i-fiov.-- Mule spinner i,asbestos), last 13 years; nondusty trades, 4: i veur-. idle. 4-; years. if.d f Vuosore.--in) Weighted average. 13.3 million p artie'es per cubic foot, h Millior. particle years, 173.7.' P as' tHuiiod.-- Ihiluen/a and piieiiniouia. 1919. Frecpient disabling colds. Cornfiln.ht*.-- None. Ph'jftcal ejcaniinnhott --Interm ediate white male. Height, 7*i inches; weight, 136 pounds. Interm ediate chest shape; expansion. 2 inches. Dry, musical rales over bases of lungs. Urinary silica, 3.0 mg per HXJ ce i24hour output. SO mg). Sputum not examined. fisoru.-cup/.--Showed -light lim itation of diaphragm atic excursion right and left with fir-t-degree dufuse ground-glass appearance of the lung field. X-ray.--Show- tir-t-degree granular appearance not obliterating the linear markings. It illustrate- the fine reticular fibro-i a --oeiated with this condition and the tendency to he most dense at the base of the J u n g s . Liiagnaxts.-- Asbe-to-i- 3.I I -,I ffU M BJt H H W W . r.i a a n w e s " U T - r MHMMNHIi l 84 .f * N - ... .1.11- --Ss*'-.~ * it X f i g u r e 47.--m o d e r a t e l y a d \ anced a s b e s t o s i s . White Ma l e , a g e 49. Occupational history.-- Mult* gunner lasbestos . 25 years, working 10to It hours a d iv; nondustv trades, 9 year- ... K-Umahtl <lnsi i r/i*r' . -- .<7 Weighted average, 7.9 million particles per c ''ic font, 'b' Million particle y, ar-. 221 2. }Jiist tit tltcrtl.~ T > ;flun<i fever at a Be of 11. Iutluen/.a. 19IS. Dry pleurisy, rieht in 1031: second attack in 1935 on left. Mure than average number of chest e d- each rear. Kidney i lie. 1'Cj1. hnnplaints.--Slight i i j o c a . specially elmd me -ta.r- Shtrht morning I'l.'ich pn-t 2 to 5 .war- p r 'd -irto e of mail arisen,t of lu te frothy -putum , /*' ,sir'll ixnm iwi' mi - Tali, ra r v wel!-(lo\> ,j ni.ni Height 70 inches, and _- t. 172 [ioUIkK Hi.. : pr-- .r- I # mi P . -e :ac. so. inti and .'> respir- 2; 32. i- : 2- t . n.m- dui'e'-. a''i,.r, and 2 minute* i - .,'a ... : :,,i \\ ,t . s i i r ilarine - .. . . N ........... . eraridm ii rule* .. ; .. - e, e n "US . .- - I r . n ; 3 2 mu per . 1. tiv-d and . ,:.g field- interpreted a --h o " mg a .'-leuive aroui.ii*a,a-s aiijrt-arai.ee. ' X -ray.--Note the fine rainy or ground-glass appearance fairly -.v.!! limited to It)heaglnoowsiear.--twAos-bthesirtdossisof3.each lung field. ,r F I G U R E 4 8 . -- M O D E R A T E ! . Occupational history.-- B r trades, 7 years. Eftin,al-<1 ilost (fpofnire, cubiefoot. I, Million part Past !Tn.1 --Bilateral r years. Typhoid fever, 1911. Com ole --Dry, hack it vi-cid sputum , pa-t 2 year-. ! Physical examination. -- Ft incite-: "eight. 103 pound-. Respiratory rate. 2 1 . 39. am I functional everci-e te-tu ( l Heart -.-und- are di-tant \vr f Ftmonfu/iij --Peaking of 5 forced r-n:sat..it, ; ^ X-~o ~ N.-te t-.e -hO rni t _r><i 2 j \ i M .l.-.r,,w 1 .ii.iiRiawaiH t} ,.ar i It! t S .) u s . W h i t s M a l e , a g e -59. >years, working 10 to JI hour* ;e, 7.9 million particles per fluenza, 1918. Dry pleurisy, than average number of chest `bine stairs. Slight mom ins of white frothy -puturn. ' man. Height 70 inrhe*. and - rate. SO. 100 and 80: respirlediately after, and 2 minutes 11 developed with sonic daring '. Numerous crackling rales nit uin (-ingle specimen * was .. Urinary silica. 3.2 m s per itlds interpreted a# showing a tpearance fairly well limited L- F ig u re a s --m o d e r a t e l y ad v a n c ed a s b e s t o s is . v. h it e m a l e a g e ; ? Occupational history.-- Broadcloth loom room iasbestos , 14 years: nond trades, 7 vears. . Estimated ,t,,t 'rp n su re .-(a ) Weighted_ average, 49.7 milhou particle- l-er cubic foot, d>- Million particle year-, 4*79.7. _ Past multi-:'.-- Bilateral pneumonia a. a child. Sinn- disease for the pa.-: 2 years. Typhoid fever. 1911. _. Complaints ---D ry. hacking, tnorniug cough productive of 2 ounces of wr..Tc. viscid sputum , pa.-t 2 vear-. Shortne-s of breatii, 2 : year-. Physical tramination.-- Fairly well-developed, slender, white mam Height. 72 j inches; weight. 163 i>ounds. Blood pressure, 104 i0. Pulse rate. 68, 76. at. : >. ' Respiratory rate, 21. 30, and 30 (before, immediately after, and 2 minutes a :;-r functional exercise test). Chest is long, slender type, hxpausion, 1 ". ii.cr.es. Heart sounds are distant with a pulmome second sound somewhat accentuate,:. Fluoroscopy.-- Peaking of the diaphragm both sides. 3 cm excursion up* i. forced respiration. . X -ray.-- Note the deformity of diaphragm. This case is the only one showing definite deformity in th e group. The lung fields were interpreted as ho.:.g second-degree diffuse grainy or ground-glass appearance with emphysema. Diagnosis.-- M oderately advanced asbestosis (asbestosis 3i. HFIW" '"H.iHIIMI^ggpjjpjawyii Ti mmm pHftPIWum"1-1"1.Jliliw mum n'nBit iff intMHim-iTi 86 i L, F ig u r e 49 --a d v a n c e d a s b e s t o s i s . W hit e m a l e , age 48. F ig u r e 5 d e c l `ixt"1' v,-- M 'ii** -pinner ta-bo-to-e. ITS yout- l .years in -am e room %it 11 carding m achine-. 11 w a r- lie worked 1 1 in tv a 'lay . nondust y trade. Occupational lush trade.*, 27 years. 17 vear. . Estimated dust t E 't.ion`-il dost tinn.-ur, -- r Weighted average, 10.U million iarfides ]>er cubic foot. (h> Mi c u b i c : --- > Mi!:."! u.-i-i f!e w a r., 103.v /'../ . ii! --. l-'rei:'ie; t c:,f.t fold'. Aerophagia for several year. Malaria East utttiical. -M Complaints.-- I )r\ admit 10`2*i. lntl'a- . . ''*J `*a : 1 1032. Cut,. '..i-- *ii:r a t i * , p. " it.h soim-ft: m improved since spilt inn over a pern walk very slowly t> U'litt V ... >. . a- ' > \<TI- pat'ixv-m - o f cough paTVi.E. cau-ing inm to you. ~ aen u eio li a '.d pro.nieriw of 'tuali am ount of ft*: a*-."':- mucoid -putum . Moderate dv.pnoea duet* 102s. unchanged. J.o*t 15 to 20 pound* in weight and 4 year-. Physical fxtlmina sure. 112 70. M -! a --ocia** : fteakin-" defore u lifting work in a-:*e-t _ rate. 4s, 5.}. an i Ph<isirnl fxantt nation.-- i'lemivr fairlv fteil-de\t :opeu a!, i !.o ri-l.ed white male. Height, lis ine!u-. weight. 131 pound-. R ather long narrow chest. ' | exercise test . 11 . exercise, but <*i Chest expansion, IC inches. Tactile and voice fremitus apparently normal. Slight runaired resonance loner half of each lime. Numerous persistent dry crackle- mostly over lower portions of lung-. Faint drear':, sound# lower one- half rig: t and left: 1-- ca rtin g of finger nail*. Blood pre--tire. 135 *>0. Pui-e and n -' r;n,.rv rate, re-'.e-c'iw lv. 72. 100. and n> and 2s. 32. and 2s, !>of..re minedlatelv after, and 2'minutes after the functional exercise test*. M oderate dv.-ptmea following tlii- exerci-e. Crinary silica (single .iiecimeid, 2 mg per 100 ce. sputum negative for acidfast bacilli and asliestosis bod.e*. Fluoroscopy.-- 2 ~ lag of diaphragmatic excursion right at-d left. R ath er poor { | f ; , | * Breathing i* hi r. over the lower iiaif with th e aortic se second. Fir-? .-out 2--curving of tin- ti Fluoroscopy.-- Ao 1 -- increase in aim 3 cm on forced excut A'-ru//.----Shows d radiolucencv lower lung field*. A'-ru . - Sliows -econd-di-gree grainy appearance with almost complete obliter tinctly linear markiDiagnosis.-- Adv: ation of linear marking*. Generalized fibrosis 2 -r. i\ Diagnosis.-- Well-established asbestosis. 43162-- 38-------- r V' i r f ..... .......... - mi'i ii'iififtiiitfHiiii i! itiwMamiii fan. 87 MWWWfl i ? I I i GE 48. i .l','a r ' itt same mmdiwty trades, >n particles per years. Malaria improved since mg, causing liim mucoid sputum. (is in weight and nourished white t narrow chest, latently normal. s persistent dry unds hover one. 133 SO. Pulse and 23, 1before est). Moderate >i. 2 mg per 100 t. Rather poor omplete obtiter- j ^ | f 1 I ' i : J f i g u r e s o .--a d v a n c e d a s s e s t o s i s . w h i t e m a l e , a g e 55. Occupational 1. is/ery.--Preparatam departm ent :asbestos', 14 years: nominate trades, 27 years. Esttmatnl '>.-- a< Weighted average, 3S.9 million particles per cubic foot. Million particle year-, ."to. ' Past Hflu-nl. -- Maxillary -inu-e- drained m 1030. Typhoid fever as a child. Complaints.-- Dry e instil. 10 year-, productive of 2 ounces of white, thick sputum over a period of 24 hours. Rather severe dyspnoea, 3 years. He must walk very slowly to prevent dyspnoea. Occasional edema of ankles for the past 4 years, * Physical la m in a tio n .-- Height, d*l inches. Weight. 132 pounds. Blood pres sure, 11270. Moderate arteriosclero-is. Puke rate. 72. SO. and*>3. Respiratory' rate, 4S. 34, and 31 liefore. immediately after, and 2 m inutes after functional exercise test , Patient stopped on completion of about one-half of prescribed exercise, but expressed a willingness to continue. Chest expansion, 2 indies. Breathing is labored and shallow-. Prolonged expiration. Fine crackles appear over the lower half of both lungs after coughing. H eart is enlarged to the left with the aortic second sound somewhat more prominent than the pulmonic second. First sound at the apex is split and is particularly snapping elsewhere; 2 --curving of the finger nail-. _ Fluoroscopy.--Aortic -l.adow is definitely widened. The cardiac shadow shows I t increase in size. Diaphragm on ordinary breathing moves a scant 1 cm; 3 etn on forced excursion. A'-ro.v.--3 huws ditfti-e ground-glass appearance. Note th a t most of the dis tinctly linear markings have been obliterated. Diagnosis.-- Advanced asfiestosis. Iff' 'tm M W -I-S, iHUiiwmuwK w* . # 88 * > I * % { Preceding swum I the X-ray findingf reason, of course, i- now avu'd.'.bn .` >1 >i ? on the hotly; nam< t Classification of a another in tlicir <h . to a great degree f I" the hirig-fiehl mar same difficulty. ' i Dooley, Matthew eases of asbestos is less corresponds t eases in which di ' represents early cu advanceti cases, infretpicnt. Stag T a b l e 41 X-ray Cm)mg F ig u r e 51 ,--a s b e s t o s is w it h f ib r o id T u b e r c u l o s is . W h it e Ma l e a g e 38. tireufullihMil hir.1i,i Mm>- -p.nner trades. 12 year.'. t*- , 11 years s m onths' Imndusty ' 'hi*! t,rp,,*,,r < n Weighted y \. ' ia i. 7.0 njil'n'U particles per cubic f<mt. h Million particle year-. /Vm/ n,i ,lirul.~ R eceiv ed sanatorium lrealnient for i 'll rculosis > m onths in 1030 Unit pneumonia a-'a child. Appendectomy in 1910. i .o,ipiri'f.'.\-.' Ihy eoeui, pa-t .i ji'n r., worse at uiclit. SlicUt dyspnoea, 8 years, Hhiti'iffil ixniim m lwii.---Very thin man. Weight, 131 pounds. Blood pressure, lot) 70 PuUe rate. 72. Ml, and C>v Respiratory rate. I it. 10, and 20 tbefore, immediately after, and 2 m inute' after funetionai exorcise te sti, Asthenic type of eh<-t. Some deformity of chei due to sColinsU. Chest expansion, l 1; inches. Bream Muimi, are sinti.tiy o <reap 'd o u r the extreme right upper. Very few drv rides risriit s<u<ri--capula f o -a . Heart: Tin* pulmonic second sound is much e;t at, t h e ,e .*,d. h i u < i - --liiapi.racm moves ireely arid equally on both sides. On forced re'iurat io*.. exetir-ion i~ d cm on right and 4 cm on left. v--Moderately ad\ a need ysU-!,..^ woh arrested fibrotie tuberculosis ' . | | { " Total........ . . SFelrfsntn-.ill-eUgr'uwrvlvinleiawr i.r. -. -. - First-.lenrw nountl s ! e . .. Seeuniistegree gri.un4 glas Table 41 Host X-ray findings, occasionally mat markings when t in sufficiently ad tosis were not nr present in the hi The incidence exposure. A iif particle years, i than 100 niilli*' anthra co-silicosi INCIDENCE OF A8BE>TOSl> Preceding sections of rids bulletin lutve -tre~-ri tbe unportan-e <>f the X-ray findings in establishing a diagnosis of ashestosis. The reas-ut. <u 't at X-ray examination is the most direct means now avutlab.- i *r .: reeling the primary effect of inhaled asbestos lust on the body: namely, initiation of interstitial fibrosis of lung tissue. Classification of ashestosis into a series of stages which follow one another in their development is a difficult matter because it depends to a great degree on the interpretation of relatively minor changes in 1 the lung-field markings. Other investigators have encountered the same difficulty. Lanza. McConnell, and Feline! <17' and Fulton, Dooley, Matthews, and Houtz (1.5) set up a category' of doubtful cases of asbestods, Stage I in the accompanying tabulation more or { i less eorrespoiuls to their category of doubtful ca<ds. It comprises eases in which diagnosis rests largely on X-ray evidence. Stage 2 k represents early cases of ashestosis. and stage 3 designates moderately advanced cases. More advanced cases istage 4. are relatively infrequent. Stage 5 wa- reserved for bed-ridden cases. T IPLE 4 1 .-- / 0 hi: " t t of axhfstosis It! I'thg-fitltl HtQrktngs j StjiesdfUafwiT'J-.i X*raj ir .'; .itc?ent T*d,il l 2 A4 Wh it e Ma l e a g e 38, rs 8 months: nonrlusty tlion particles per cubic icrculosis 8 months in iieht liysprmea. 8 years, mrnls, Blood pressure, lb. Iti, and 21) before, e test). Asthenic type t expansion, inches. *iht upper. Very fe c second sound is much both sides. On forced ted fibrotic tuberculosis T*ta1....... - . .. F,r??,4itrjre*i l5nv.tr __ 'rw l.:> ;f............... FifM-ite-rr* ifouJM v " .. . . ...... e r r 1-.a--....... ....... :tr. .4 27 tin l 6 li 4 ... ............ A* 1 2 1 >' : ........ .. * .. . *7 4-n AC 7'j 4V 20 Table 41 illustrates the relationship of stages of ashestosis to the X-ray findings. Although diagnoses of early stages of ashestosis were occasionally made in the absence of definite ground-glass lung-field markings when cough, dyspnoea, and objective findings were present in sufficiently advanced degree, diagnoses of the later stages of asbestosis were not made unless unmistakable ground-glass markings were present in the lung fields. The incidence of ashestosis increases rapidly with increasing dust exposure. A fifth of the workers with an exposure of 5tt to no million particle years, and half of the workers having an exposure of more than 100 million particle ytjhrs had asbesto-ds. In ci&nparisonwith nnthraeo-siiicusis these are exceedingly low dust-expo-Ire values m M ill n il'll llllIilhli f iill w 'lll < > il||| DO The relation of asbestosis to dust concentration and length of eraployaient, in table 43. is of great practical importance because it shows what working conditions are most likely to cause asbestosis and how long a period of exposure may elapse before the disease becomes evident. T \ ble 42.-- R ilnt'iin o f asbestosis to total dost npni-ort 1 DiatiM'.i XIillK-a I t^J'poian 25 io 4D s*->o 50 ;o Dv ' 't er Uw.i Tf'tal E ^ tr - \ u i \ n o r n u l ......... ...................................................... e . 4 ...................... . ........................ ................ .. .................................... T-:.a............... m o i) 0 52 3t 32 25 1 1 23 25 0 r. n t: u ** V 105 HI lw* 7. ! u-.t Jpersulis U i . d l \ f | " ^ ..r v tubergiikteii Ba-.e T a b l e 4 3 .-- O t r o t *hom/>T* .'L** ti r*bit/ou t<* d'nt concf k n, ;/o /it tit 'E Kf" F \T .V E WITH X^HF.^ToMi and Ifuth V if* r. uviu-tr} f * l [ * i 0 t o 4 * " T o 4 <4 1 \r!t(i-l............. ..............................F i p - r - n : id c * . .. - 1 P * r<> l i t u f . m .................. . . . M (i ' ....................................... , T \ ; * -- a ............................... . . . . i F v n v i u j f ........................ 134 ' 'll o '* O w l `t 1 lv* ft 3? ; r. % *> iv J r'' ll 5 13 Y* *> ' V. >* c The percent a:re of person- with asbestosis increase- greatly with tncrea-mg length of employment. J.anza. Met 'onm!:. ;.t;d Fehnel i IT * rep"t ted 1 -iniilar tretid . their pen milage \ ..1 e--are ..'luT than these. There are two explanations lor the small number of person- employed 1." year- or mote. This group of asbestos textile mm..;:.-- i-,a- been in operation from fi to ]> year, and because of the relatively -Port . ^ life of the industry in this section of the country c.imparativeiy few | persons have been exposed to asbestos dust for a long time. Another explanation is suggested by the fact that almost three-fourths of the Worker employed more than 15 years have the early stage-, at least, of a disabling disease, asbestosis. Since there is no satisfactory way of locating and examining person who drop out of an industry because of disability incurred therein, the percentage values of the foregoing tables are necessarily minimal estimates of the prevalence of " asbestosis. { * ` * ; j | The incidence tration. In their asbestos textile fi found that 8 pen cent rat ion of 5 m cent of the 17-mil particle group Inn THRI From a practici medical and engi working conditioi concentration of would not produ during their cntii as in mit of the very few woikme; centration of as problem, it seem define tentative for the guidance of data are available In an analysis o exposures are of c safe limits of expo vidually, a well a unusual features 2.5 million partie offers no difficult! centration- below asbe-toi. nithoni employed more th in the range 2.5 t< Because elean-e contra'on exceed th e y v (](> n o t fill.!: pel' c u b ie fo o t m ax asbestos-dust expo In order to find * have been reduced an asbestos textile recently installed, reducing the dust to le.-s than 5 milli P iP P M ii W* s jm w f i and length of m ortance because it to cause asbestosis before the disease ffpf/s'ire * k1*yvic^ --~ Jntj] ^!>/W <K*fM* * | | | 43 u5: <6\* Znri 56 ijA eptilmatkMT tubert,ulOishav etrttratian and length nf in aOi-tos '."-iji'Try 3 to 9 S Ik,-r m | rn <'; /', j** wu f S. ases greatly with m- tell, and Fehnel tl"'1 re higher than these. of persons employed e factories has been the relatively short v comparatively few long time. Another three-fourths of the arly stages, at least, no satisfactory way t of an industry be- , ntage values of the of the prevalence of i S ( * i J ^ t 01 The incidence of asbestosis increases with increasing dust concen tration. In their report of a similar study carried on in I'enn-yhama asbestos textile factories. Fulton. Dooley. Matthews, and Houtz (15) found that 8 percent of the workers exposed to an average dust con centration of 5 million partible* per cubic font bail e.-be-P'-i--. 22 per cent of the 17-midim!-:" ; *<!<_"i ;.:d '7 ; es ' T-i-million- particle group bud .1-1 <-u-,.-. T H R E S H O L D O S C K M K VI ! o s <U ut-l From a practical standpoint, one of the tno-t ii:q r.m t results of a medical and oiurineerittg -tudy Mich a# this is the definition of safe working conditions in the.industry under study. Ideally, a threshold concentration of dust should be the highest dust concentration that would not produce pneumoconiosis in originally healthy workmen during their entire working life. The chief difficulty in this study, as in most of the earlier studies of the Public Health Service, is that very few workmen are exposed for a long period of time to low con centrations of asbestos dust. Because of the importam -e of the problem, it seems to be de-irable to use such data as are at hand to define tentative safe working conditions that may serve as standards for the guidance of factory managers and engineers until more complete data are available. In an analysis of this kind the oases that occur at relatively low dust exposures are of especial dirnifieance because they indicate what the safe limits of exposure may be. These eases must he examined indi vidually, as well as statistically, in order to be sure that there arc no unusual features that would complicate statistical analyst-. Below 2.5 million particles per cubic foot, the interpretation of table 43 offers no difficulties. Xotie of the 8'.t persons exposed to dust con centrations below 2.5 million particles per cubic foot had a case of asbestosis. although, as a matter of fact, only G persons had been employed more than 5 years. Three doubtful eases of asbestosis foil in the range 2.5 to 4.0 million particles. Because clean-cut cases of asbestosis were found only in dust con centrations exceeding 5 million particles per cubic foot, and because they were not found at lower dust concentrations, 5 million particles per cubic foot may be regarded tentatively as the threshold value for asbestos-dust exposure until better data are available. In order to find out the levels to which asbestos-dust concentrations have been reduced in practice, an engineering study w ' was made in an asbestos textile factory in which dust control equipment has been recently installed. This shows that means are already available for reducing the dust exposure of a,majority of asbestos textile workers to less than 5 million particles per cubic foot. f| wmmKsvmW* 92 The data of table 43 provide a simple means of comparing asbestosis with other pneumoconioses. In a previously reported study of the Public Health Service (51) it was found that workmen in anthracite mines could he divided into three groups which differed with respect to the nature of the dust to which they were exposed. The percent- Table 44.-- Percentage* of workers exposed to certain concentrations of asbestos dust in asbestos textile factories where dust font rut measures are used to a it lied extent and in factories irhere effective dust control is practiced , Dim concentration miUton putride* l-er cubie ft.ut I,imitei! S Extensive Ufeofclust- use f <lu>o . control enrurni measures ! i measures *. O viflft... ........ , 5 t9A*................... *2.5 0* 4 9 .............. 1'iuUt 2 5............... *s : 7 28 17 15 ' 32 9 44 >Orna ff'im table 41. Onta (r.itu IT! ages of men having any stage of anthraco-silicosis (1,2, or 3) have been tabulated separately for each group in relation to average dust con centration and length of employment. In passing, it may lie of in terest to rail attention to the difference between the pneumoconiosisproducing power of the three kinds of dust encountered in anthracite mines. If one compares groups of men with the same dust exposure and the same length of employment, in general the percentage of men with unthraco-silieo-is increases with the free silica content. 1T \ b c e -4.1.-- /* / i m i f o g t o f m e n h a v i n g a n t h r a c o s 1i c o s i s 1 1,4etVaxmpa-mo'd-?'ilinT!evd**i*u%tfritti.jir<nn**rm*3*- *t peff.m s.J.ri o r(Wpiitealfr'nutmcVulea-inanjeitmuef.uninwo'p-i-->tsiiyfvi<nuws*<!<iihfMmi<d1 l.il rK-foc\*Uwio<r\keeor*t\nvmx-tnt ab o u t 33 frw*silica l>u-* c-.u*-' in uitU' -it ]<r* ------------ -------------- ---------------------------------- "* lie - * per cubic foot Year* m industry Y ears ttt iii^ tw ry Y ears tn m *hM ry tu n i:I* 21 O t j f , 15 !..*s tirali 15 ru 24 U\tT Is. L is. than 151.24 13 1 Over 25 5 to 1*i> Ml << ................... ............ 1 .1 l.:> 7 I 0.4 1 X 14. 1 54. 0 0 0 2\ 9 71 1 fit ; 7 ,%l >- :* 1 , 0 <*' (' *\ 3 2 >.3 f-. O'- 13. S i as VS \1' ib ' 71.4 in. 2 <b (l\ V4 tt Ir r -. * i t* p 7e. T u ' Ik' * Less ibau 10 m en cxHtuiaeii, ilu.i* i:.. N .7'. A' in adaMo-i-. the i.'u orlici' ni' menino,-ohiod a ne mg aiithracit mitico inerca'i" with neroadug length of employment. There is a much more definite increase in the incidence of antbraeo-silioosis with increasing dust concentration than there is in asbestosis, probably because men were ex] trations in anthracite In comparison with cite mines, relatively tively short lengths < result in piieumocon There was no free asbestos textile factor According to table ami 378 men anti wot asbestos textile fact exposed to apprecial included.) Eight per study had asbestosis dence of asbestosis he these factories 15 mm of the discharged a-f Shull <31', Donnelly attempt was utatle to cases, only tin could 1 according to the diair assumes that the nut the same behire thest study was made, am charged cases had : observation. Atldim sum by 447, and nml 27.5. This is not an of the dusty trades has been found to hr may be mentioned, in lead and zinc mine (49), 21.3 percent ha "The prevalence of . ployees was found to Oilier investigato.* asbestos textile fact ported. "Of the tota second-degree a-bost negative." The pej random from among in the industry." S the factories he stm are not directly coni} I 93 comparing asbestosis ported study of the fkmen in anthracite liffered with respect ased. The percent- I f i ttmiionx o f mbestot 4tlif ' used to a limited extent 1 2, or 3) have been average dust con i' it may be of ki te pneumoconiosistered in anthracite tnie dust exposure percentage of men content. ilicOAi'.* 1 ,t 1-51 r<wk w-irkorinr^*sp*-. j , -'w .i.fiit jhtc nr fee i.Iica \ears in inlu-4rry i Less I itam ! 15 I5t .24 ' Orer 25 fit n. >. 23.5 s <* . Cl nh.4 , fit (4) 56.2 ' 92 0 unong anthracite tent. There is a raco-siJicosis with estosis, probably f I I because men were exposed to a much greater range of dust concen trations in anthracite mines than in asbestos textile factories. ha comparison with the three kinds of dust encountered in anthra cite mines, relatively low concentrations of asbestos dust and rela tively short lengths of employment in the asbestos textile industry result in pneumoconiosis. There was no free -ilka (quartz) in the du.-t encountered in the asbestos textile factories. According to table 43, 10.3 percent of 09 former asbestos workers and STS men and women employed at the time of the -tudy ir. three asbesto- textile factories had a-he^to-i-. Persons who were not exposed to appreciable quantities of a-be-to- dust have !'.>- hem iaehnledd Eigftt percent of the 378 workers employed at the time of study had asbestosis. This docs not completely represent the inci dence of asbestosi- because about 1.1(1employees were discharged from these factories Id months before the present study was made. Many of the discharged asbestos workers bad asbestosis, as the reports of Shull (31', Donnelly (12 , and McPheetcrs >23 show. Although an attempt was made to examine as many as pos-ihle of these discharged cases, only (9 conld he examined, 43 persons of whom had asbestosis according to the diagnostic standards employed in this study. If one assumes that the number of persons employed in these factories was the same before these 15o persons were discharged as it was when the study was made, and if one as-umes that i>2 percent of all the di-- charged cases had usbe-tosis, then 30 cases of asbestosis escaped observation. Adding thc-e to the 73 that were found, dividing the sum by 447, and multiplying by 100 gives an estimate! percentage of 27.-5. This is not an unusual percentage value, in numerou- -rudies of the lusty trades the percentage of workers with pueum miosis has been found to be between 20 and 25 percent. Two <u h studies may be mentioned. Of 7,722 miners and men seeking employment in lead and zinc mines at Picher, Oklu., who were examined in 1**27--2S (49), 21.3 percent had silicosis. In a study of anthracite miners i5i i, "The prevalence of anthraco-silieosis among the entire group of eraplovees was found to be about 23 percent." Other investigators have reported the incidence of asbestosis in asbestos textile factories. Lanza, McConnell, and Fehnel 17) re ported. "Of the total 4 120 X-ray examinations, 4 were diagnose! as second-degree asbestosis. U3 as first degree. 3n as doubtful, and 2" as negative."' The persons he studied "were selected more or It-- at random from among ti,..-e having more than 3 years of employment in the industry." Since Lanza lid not examine all the employees in the factories he studied, percentage values calculated from his data are not directly comparable with rate of incidence for the present study. Ttmmif* jwmiujHp