Document MG41dzVDmVd11y5eZ3xpK863V

FILE NAME: Talc (TALC) DATE: 1943 DOC#: TALC004 DOCUMENT DESCRIPTION: Medical Journal Article - Dust Hazard Tremolite Mining iate Pro'niversity we might ting, par- organized no meant Vito York done very organized our State, upon the . if 1 were tt various side oj our <est of this II sense oj thingsfor dais, hut 1 lone all of li e them so `i hack of it I to the fact an horn on orn on the ; had to go g not only a nrofessional eat pleasure e American Harrington VOL. 49' No. 1 F th e dust h a z a r d in tr em o lite t a l c m in in g , 1 INCLUDING ROENTGENOLOGICAL FINDINGS IN TALC WORKERS . fly W ILLIAM S1EGAL, A D E LA ID E ROSS SM ITH, and LEONARD GREEN BURG from the Division of Tuberculosis, New York State Department of Health, and the Division of Industrial Hygiene, New York State Department of Labor FR O M tim e to tim e the attention o f the Division o f Industrial H ygiene has been drawn, through compensation claim s, to incapacitating fibrosis in talc workers. Since silicate dusts, o f which talc is one, have been considered relatively innocuous in the opinion o f most authorities (thesin gle exception being asbestos), the occurrence o f these cases has naturally raised several questions-- the obvious question as to whether this incapacity has resulted from talc exposure alone, and the second more interesting question as to whether industrial hygienists, with few exceptions, have erred in considering asbestos to be the only in jurious silicate dust. In an attem pt to answer these questions, the study here reported was undertaken. I t consisted o f an investigation o f the talc industry and an examination o f talc miners and m ill w orkers in northern N ew Y o rk S tate (St. Law ren ce C o u n ty) m ade, in 1940-1941, as a join t enterprise o f the Di vision o f Industrial H ygiene o f the State Departm ent o f Labor and the Division of Tuberculosis o f the State Departm ent of H ealth . NATURE OE TALC T a lc is a hydrous magnesium silicate with the formula H jM gjfSiO aL composed, according to I-adoo15 o f abou t 63 per cent SiO,, 32 per cent M gO , and 5 per cent H ,0 . I t is usually a secondary m ineral re sulting from the alteration o f other m ag nesium silicates or carbonates. W hile its own silica is present in the com bined form, most talcs mined com m ercially contain varying am ounts o f such im purities as quartz, calcite, dolom ite, iron oxide, etc. Talc has a characteristic soapy feeling and a pearly lustre. It may be pure white, silvery white, gray or green and, when im pure, yellow, brown or reddish. T h e most common commercial variety is a m assive, foliated, or granular type, but it m ay also occur in a m icaceous, or in a fibrous form. Soapstone is a closely related substance, being essentially an impure talc, and when pulverized it may be used for the same pur poses. T rem olite, w hich is a calcium m ag nesium silicate, changes over to talc. 11 m ay be mined with it and subsequently ground and sold as talc. GEOGRAPHICAL DISTRIBUTION T h e U nited S tates produces abou t 65 per cent o f the w orld's supply o f talc, the leading states in its production being Vermont, New Y ork, California, N orth Carolina and Georgia. THE INDUSTRIAL USES OF TALC According to the M inerals Y ear Book (1938) o f the United States Bureau o f M ines, the use o f talc and soapstone is steadily increasing. Ladoo" states that at least 60 different uses for talc have been noted, though most o f them are o f minor importance. Its value depends chiefly on its usefulness as a filler, inert extender, dusting powder and absorbent. In 1921, according to Ladoo, the m arketed, ground talc production in this country was in dustrially distributed as follow s: paper 38 per cen t, paint 23 per cen t, prepared roofing j 8 per cent, rubber 9.5 per cent, textiles 4 per cent, toilet powder 2.5 per cent, other uses 5 per cent. William Siegal, Adelaide Ross Smith and Leonard Greenburg ia e,ght weeks. No significant tissue changes were T h e other uses for which ground talc is adapted are: as a filler in soap; m foundry ^ Bethune,* in .935, was able to produce pleural facings- in wire-insulating com pounds m d rv"u br,can ts; as a filler in cotton textiles; in the dressing and m anufacture o f leather as a cleaning and polishing agent lor rice, p e a s , coffee beans, peanuts, e t c .; in m aking S o r e d crayons; as a filler m wmdowshade the peritoneal cavity, but that such adh" ' " Sf were not related to the subsequent behavior of cloth; as a dusting agent in m aking cand y, chewing gum, etc.; and as an ingredient o f th F?enbergMn . 937, having observed granulom l from fh e surgkal use of talc, experimented concrete, plastics and insecticides. with the injection of this substance. mice and Since 1921 there has been a m arked in obtained subcutaneous granulomas m these crease in its use in the ceram ic industry. Fourteen thousand more tons of talc and related m aterials were sold in iy 37 than , ,936 and about 10,000 tons o f this increase amount went to the ceramic industr where anM d k l and Sayers," m .93b, reported studies in which talc was included among the dusts whrse intraperitoneal reaction in guinea pigs S t u d i e d ' They found that it produced an talc is chiefly used as con stitu ent o f glazed wall tile. REVIEW o r LITERATURE ON THE EFFECTS OF TALC DUST that such dusts should be considered as poten- Experimental Stnehes. D uring the las ten vears a certain amount of experiments work with talc dust has been reported, bu on reviewing this literature most o he in halation experiments are found been o f insufficient duration to be hetptul in regard to the probable effect o f long con on Silicosainsd( 1s9o.mWe- ot. the c.lay mmiinnfexrraalUs hnaavvee provoked chronic inflammation (of but this reaction has tended to retrogress after tinued industrial exposure. In 1931, Haynes'* included talc in a series of dusts studied for their reactions on guinea pigs. Twelve pigs were dusted two hours daily, except Sundly for a fortnight. The author saw no sign of pulmonary damage, but found that bronchial and lymphatic rernova ocTUrrecl un usually brisklv. He concludes that the sub stances dissolved from talc are o f a low degree o f toxicity but sufficiently obnoxious to neigh boring tissues to cause the removal o f cells containing them. . , .. . re. Stber, in 1934, studying the cellular re snonse of lymph nodes to various dust sus pensions introduced into the lymphatics, found that talc caused no apparent cellular prolifer tion within the lymph nodes after five days. After 10* days the nodes were still normal and showed no increase in connective tissue. Fossel,* in 1935, reported which guinea pigs were exposed to the inhala tion ,/ ta lc for one hour daily over a period of I r S S S ; dustria! talc three hours a day for twelveJays The intensity of the exposure was high. Me found that the dust was six days after inhalation began, he found uilat t on of bronchi, acute emphysema, and exuda tive alveolitis. Many animals died spomane- <)usly with the bronchopneumonia. ^ h concW ,on con- S T b e possibility'of1pulmonary fibrosi. McCormick and Ramsey," m 194, reported postoperative, peritoneal granu.omatous in- flas" nn" wilhams m ^ n j e c t e d intra- Vol. 49, Clim cupatic this coi and ui DallaV talc wc Pohc; questioi the hur time a ] lished t tion o f t of forty years in Thorel . taming o f certa tions, rr accumu nodular present, o f tubei In 19 stated t gerated opinion Zanel the com to the fa dangero ntoconic Mere' rubber t two yci "Sioce t Hobbs Rourro dcxri M fcttl ter* Ni'Atr *941 m g fs were u cc |>lcur*i g conirnerMiller :i<l adhesion* dust*' i"*" adlu-sM** ichrtvifr ol <! griiniil"lerinu'ntcd il mite unti in tlnst reti studies the dusts uiiie l,'Ks odmvd an k* injei ted t minai*- a the sigili** S eimhnle i its tal wnik on army sani 'Ymj**x,um s like fine ends li;lvr the lungs) greM* afie i a singe ut hin period* . indication jKrinient in oliateli, inwclve tlays. s M > . H1' . the uppe* irked d>Tetl two anti .timi dibit*1" and eMitlnI spontanraml loei of ititm of tbe elusion '`,m' try fibrosi*. t i, reported ntatiuis nt- ected inti**' The Dust Hazard in Tremolite Talc Mining 13 I * . * 0- 1 BEitoneaUy in guinea pigs a series o f seven SfEgercia] talcs with different silicate-carbo* & rttio s . Animals were sacrificed at intervals foring from ten daVs t0 fif(een months- In al1 the pathological histology showed the ldingof talc particles in a local area by phago- : cells o f the macrophage and giant cell . progressive fibrosis was not found. The KJrrosis which occurred was only enough to hold nd limit the space for storing the foreign ma- K teria l- The greatest amount o f fibrous tissue ^developed in the presence of the two talcs which ' ` ` contained the least carbonate and the most talc T and tremolite respectively. Clinical Reports. T alc fibrosis as an oc cupational disease has received attention in t|,js country only w ithin the past ten years, r-rand until th e studies o f Dreessen and DallaValle, discussed later, extrem ely few talc workers had been studied anywhere.* Policard20 says that it was in 189b that the question o f the action o f industrial talc dust on the human lung was first considered. At that time a pathologist o f Nuremlierg, Thorel, pulrlished the results o f the pathological examina tion o f the lung of a tuberculous woman patient o f forty-four years, who had worked for many years in soapstone dust. According to Policard, Thorel demonstrated the presence of cells con taining soapstone dust in the cavity and walls o f certain alveoli and the existence of forma tions, more or less nodular, resulting from the accumulation o f cells filled with talc. Other nodular formations of a tuberculous nature were present, and Thorel pointed out a combination o f tuberculous and pneumoconiotic lesions. In 1915, according to Policard,20 Hayblirst stated that work in talc dust favored and exag gerated tuberculosis, but the basis for this opinion is not known. Zanelli, in 1931, quoted by TeJeky," came to the conclusion that talc dust, though belonging to the family o f silicates, ought to be considered dangerous and likely to produce typical pneu moconiotic lesions. Merewether1 in 1933, reported the cases of 11 rubber tire workers, exposed from ten to thirtytwo years to French chalk, a fine granular * Since this report was w ritten, Porro, K W ,, Patton, J. R. and Hobbs, A A ,, Jr. (Pneumoconiosis in the talc industry. A m. J . R oentgenol. & R a p . T h e m , A p ril, 1942, 47-, 507-5*4) have described pneumoconiosis in 15 tremolite talc workers with a fatal termination in five variety o f talc dust, who showed diffuse inter stitial fibrosis by roentgen examination without clinical evidence o f anything more than a peri bronchial increase m fibrous tissue. Thirteen additional workers, with exposures o f from four and one-half months to forty-eight years, were examined and reported upon the following year1 confirming the original findings. In 1933 a report was made by Dreessen8 o f examinations o f a number o f workers in silicate dusts, including 57 men exposed to tremolite, a hydrous calcium magnesium silicate containing no free silica. The findings in this group were as follows: more fibrosis than usual 67 per cent, first stage pneumoconiosis 26 per cent, second stage pneumoconiosis 2 per cent, normal lungs 5 per cent. Dreessen described the first stage pneumo coniosis as similar to that produced by cement dust; " softer" than that resulting from silica dust, a " diffuse, fine, generalized fibrosis-. . . chiefly confined to the lower two-thirds of the lung fields." In 1935 the same author, together with DallaVaile,4 reported on the effect o f exposure to dust in two Georgia talc mills and mines. The dust involved was, again, a calcium mag nesium silicate containing no free silica. It was present in excessive amounts, over one and onehalf billion particles per cubic foot in some operations, the particle size averaging less than 1 micron. Sixty-six workers were examined. Among these, 22 (33 per cent) showed pneumo coniosis, 8 in stages two or three, The conclusion was reached that exposure to talc dust was either " too severe" in the Georgia study, or that this talc was a more dangerous dust than that previously studied. N o particular relationship between talc exposure and tuberculosis was demonstrated. Middleton,1* in 1936, referred to an unpub lished case o f Cunningham's in which pneumo coniosis was found in a talc grinder who had been employed for nine years. He also men tioned an autopsy by Sand in 1910 on a woman exposed to talc dust in which " not much re action" was found. In 1938, Nuck and S/c/epanski18 reviewed the literature on talc fibrosis and added several cases o f their own. They concluded that this type o f pneumoconiosis resembled asbestosis more than silicosis. At the International Conference on Silicosis Jasuak' , >9*3 Riddell reported the results enevain_I93 . workers engaged m ^ *-- -- re- S S - r s S i'- S ! jS iT w . ` C ase Aged years the claim ant had worke manufac- in a shoe ftory- W h , shoes ^ ^ ^ and tured during about fi freeiy> dusting it on at these times he " S^ , p o f the white leather, the shoes to prevent ' Z fysed by the D.v.s.on o n m tetn a^ H ygien e and found to contain no ^ F o ise v e n a n t U n c ^ n g weak- H is c o n lti'on finally necessitated hospita treatment. . showed the presence of Physical examwalwn ,h . of the fingers. dyspnea, revealed dullness on iges. a s s a i i u f i * *- - *-* FOR DISABILITY RUF. " 'l u te ' T ^ t S S densities uniformly ( pulmonale), Hy- tricle was h y p e m o p ^ m e pulmonary fibrosis Thed>AXmwas ch terminated fatally talc dust are^ :h cases h av e oc , years. One rlS' d dur,ng the past the manu ;n the shoe ;ture o f talcl' r" f ^ r m T n talc m ining and lustry, and + /C ase v) there had illing. In one case (^ > to dust ;en significant pre sl|ic a . F iv e o f the casKWCTe'fa^ah'ln peases, summaries are and emphysema. 1^ . n ff> the hospital, nine months after _The claimant had Case m- Aged frry fifteen years with worked as a talc mm mines ten years eight months exposureun ^ ^ began previous to his ta e , with shortness of breath five years before dea work two and a productive cuug }ms because of )ears after the onset > increasing weakness, and admitred to a vailable as follows: claimant had Case i. Aged sixty-t irorked. for twelve years P ^ ,, a talcum ded with x>wder mixing ma<- n conrro!. t h e talc txhaust ventilation for ^ <)f Industrial sanatorium. . , howed an emaciated Physical " ' ,' f BfT rh ro n ic a lly ill-The vital individual w h o ' ^ k,enpr b al estimated as 3, ' capacity was i,8oo (no ()yer the middle q-he temperature was norm txt<.nsive bi cubic foot. For three or four >e. job, the claimant had with expectoration^ ^ before quitting the be. ^ <>f cough - 0,, 0j the lungs ^ The vital , "^ X ^ h ln fecrio n .p ro h ah iy tu b ercu - lousr, and this was ^ tw en ty ^ Vf^ showed moist , orma) estimated as +,h capacity was >$<*>( . . , Ume1' showed a C PRofn^ ' ^ t s m the lower and increase of bronchial m k 8 d denslty re- mucker, driller and for ^ knotlCed cough, bl erfrorne TquiottfinbgreawthorkandhsP a m ,)ms ^ He whiams easily fatigue - treacmtn t. , to enter a hospital tor ^ no lung ab- s ^ r c ^ * ^ tata,h midlung fields- . hosp-,tal of emphy- ^ f^ T sh o w e d ,,ormalt.es but sh y r t mphy, of nephros,s. hypertension ana cv acute exacer' 943 ty-two luster" tnufacar and g it on eather. `ivision -ain no <e com weakospjtal nee of ingers. icss on breath howed .odular \t ven*) . ibrosls fatally utal. nt had s with . years began breath k two tuse of i to a iciated e vital 5,oo). middle y, and ns o f acillus ty-one mes as years cough, le was d him ig abrophy. The Dust Hazard in Tremolite Talc Mining s ,,,,mination o f the chest showed Station through both lung helds below fth posterior rib, more marked m the J fh in g fid d , an increase m h.lurn shadows early f C0SIS wita fije infection, hypertensive disease and 5 nephrosis. ie case terminated iiE V Aged fifty-two. The claimant had 1 in talc mines for seventeen years with a ,us exposure o f ten years in zinc and iron , Illness began six years before death with SwMth'and dyspnea. Following the initial sympS , e developed pain in chest and hemoptysis md sought hospital treatment examination showed an emaciated "dividual, appearing chronically ill. I he fingers e slightly clubbed. The chest expansion was ded Examination o f the lungs showed dull- Siss on the right below the seventh spine with gjjfc, and diminished breath sounds. The sputum JSfwas positive. . , ,, Roentgen examination showed a nne miliary pe o f increased density on the left, a mass f increased density in the right middle lung field _jth evidence o f excavation, and heavy fibrosis S t the right base. . Jk T h e clinical diagnosis was probable silicosis, Kanplicated by tuberculosis. Death occurred twenty-one months after ad mission to the hospital. REPORT o r A STUDY OF TA1.C MINERS AND MILLERS IN ST. LAWRENCE COUNTV, NEW YORK E r Scope of Study. In the course o f this inTvestigation studies o f operations and dust concentrations were made by engineers t , o f th e D ivision o f Industrial H ygien e in p.three talc mines and five talc mills. T w o hundred and twenty-one men from seven (plants received an initial roentgen examina r e n . In the ease o f 28 o f these individuals, fcwho showed positive lu n g findings, a followEnp examination was m ade a t the end o f ten rmonths whieh included a second roentgenot gram, a medical history and physical ex am in ation o f the chest, and a detailed oc cu p atio n al history. W T h e roentgen examinations were made B n t h a 200 m illiam pere m achine m ounted K h R truck belonging to the Division o f In- dustrial H ygie n e .11 Patterson high speed screens were used, and exposures were made at a 60 inch distance and with an exposure time o f one-tenth o f a second. Type oj Talc Involved. T h e type o f talc produced in St. Law ren ce C o u n ty is o f the fibrous v a rie ty know n as asbestine. I t is noted for its clear whiteness and is used chiefly as an ingredient in the m anufacture o f pain t and tile. W ith it is found trem olite -- calcium magnesium silicate (CaM g,- (S1O3),)-- a similar appearing mineral oc curring in a fibrous or asbestiform state which in the course o f tim e changes over to talc. Gardner" reports that anthophyllite, another fibrous silicate, is also present in the talc deposits o f the St. Lawrence County region. . Analysis o f representative samples of talc from two o f the mines in the region, sub m itted by one o f the mining companies, shows the following composition: Analysis Total silica* Calcium oxide Aluminum oxide Iron oxide Manganese oxide Carlton dioxide Magnesium oxide Calcium carbonate Sulfur trioxide Ignition loss Sample A 8 24 2.72 -- -- __ -- H-5 0.23 trace 3-6 5 Sample B 57-5 5.24 *7 J7 .16 38 30 20 -- -- 5*3 9 9 *3 $ 951-oS /. T h e free silica conten t o f com m ercial talc as found in indus trial use is v ery low, Sch ulz and W illiam s21 report th at o f 51 samples analyzed quartz was not found in 25; traces o f quartz only w ere present in 25; w hile one sam ple showed a quartz concentration o f 3 Per cent The free silica content o f the talc in the mills and mines included in this study was likewise found to be low. Six samples from two talc mines, taken and analyzed by chemists of the Division o f Industrial H ygiene, showed 1 per cen t o r less o f free silica. T w o o f these samples were taken from long standing accumulations o f w aste rock; two were * includes both free and combined silica. h William Siegal, Adela.de Rosa Smith and Leonard Gree JAM-A - *r lire tale. Note bundle-like Fio. "n l,5 o X -> inch-< -) , ,, r a n g in g from 12 to 20 amounts o f quart from two mines accumulations and t.ons Of rock destined samples o f ground mills- Six mills each case the m this area. u , s . ,, G ard ner' s find- marked differenc , and ourselves, mgs and those o f D reesse^ ^ Gar(lner.s except upon th e supp^ ^ ^ quarW _bear- samples include ta|c deposit K " a. r s - - * CSn." " --. -" -s"-"by ,ta " . t ; " ; " ;.,, ,h . * 1 i;,r 2 Trem ol..et..lc Note straight needle-like fibers. (M agnificat.. 2y$0X-) v ' ; * & burg 1943 The Dust Hazard in Tremolite Talc Mining >7 9No- ` talc. Note bundle-like of fibers. (Magnificainch =10 microns.) 3. Asbestos. Note curving [tendril-like fibers. (Magnification 0,500 X.) S' ?: - . 4 ,.... ' ' ` ' * ` ' - j t v . . hr . ssi ing from 11 to 10 les from tw o mines ult to explain the en G ard ner's find,enJ and ourselves, ion that Gardner's if the quartz-bear- the talc deposit lercentages are not , is shown by the V' .. fact th at m aterial from the mills where all rock is mixed and crushed showed low quartz percentages both in G ard n er's studies and our own. Microscopic appearance. Photom icro graphs o f talc dust from St. Lawrence County show th at it tends to occur in ob long or squarish particles made up o f paral lel fibers (Fig. 1) which splinter o ff into sharp spicules (Fig. a). Its microscopic ap pearance differs from that o f asbestos (Fig. 3) in th at asbestos fibers tend to be cu rved and tendril-like in form , whereas those o f talc appear straigh ter and needle-like in structure. Trem olite talc fibers are also much shorter than those o f asbestos. In this study their maximum length was approxi mately 15 microns. Asbestos fibers, on the other hand, may attain a macroscopic length. In interesting contrast to both tre molite talc and asbestos are the flake-like particles o f mica dust (Fig. 4), another ,,0 u * _ " * * ~* *' X ' hi. 4- Mca. *ypica' mica particles, showing the very thin plate like structure. (Magnification 5.5ooX.) . W . 9 . Smith and Leonard Greenburg jASt, 1943 William Slegai, Adelaide Ross l8 T S E ; ,, ,, ,, ,, - n Sm ST S n,TM r'n " tl Description of the Industry n' UCk C A e l t r w t e . " d u t p e l i l a iS l seventeen men u n d crrTM ni - operations. T alc M ining u obtained Dust exposure in of control Mining operations. , sj,a fts are K t l ^ f m L s ison e which ts re- r d t r e Ua tg I" o n!U depths down T alc Mill Miliing 0 in all five m alike. T h e e road cars < chutes lead jaw crushei ,, c Granite. Shows lack of fomr H o o 0 n d indicate an p a r t i c l e s . ( M a g n . f i c a t . o n t,$coX > pen>- M,, tion Drilling e e .v in g tj.a tte n tm n o f^ v i.o n ^ ln - font T h e talc occurs in com - to about 1,100 feet. tbat contact p act, homogeneous s e a ^ .t o ^ inCurred with hard r o c k is l on entering a seam. there is no exposure until it becomes neces. seam. Since seams m ay a seam is entered nvthing but talc ^ another ked for years, hard rock is very ^ a r r '^ S i.h ih e of d ri." dustnal Hygiene a P little dust control * a . jn the three had been m ines studied. during drift m ade to remove th e du st ^ drilling by means [lativelv few o f these re re t'S u se d u rin g d ri.lin g o p e ra tm n s. T h e drillers w ore r e s p ir a to r , ^ ^ Tw enty-tw o dus w ith a m idget impi 8 a t v a rious operaWe re COu n te d blasting, and hand Raising and stoping resorted to, to AU drilling obtain the J ^ ^ u t i o n must is done dry since e y V hich cannot be tions and sltuat, " 5' thc tim e o f sam pling within ten hours of the t. fie,d te ch . b y means o f the low p , ' b ow n in T a b le i. nique, and gave the r exhaust device T he dust counts wherein ^concentrations bC n i en cTis'w asted Drilling crew s o f one nulled and is wast ^ doing the,r or tw o men a r c -u s e ^ ^ ^ m ocked as lt ls own blasting- ^ n ... , loaded into required by the mills. It is `an Stoping I Mocking January, 1943 ie haulagenped into a id dumped hipment to fifteen to operations. i o f control which is re- s lack of form icate and silica -ation 1,500 X.) 1vision o f Init time. Very in the three ts had been during drift home-made, few o f these lg operations. were taken arious operawere counted ; o f sampling .ht field tech wninTablei. xhaust device oncentrations i, for stoping n the general r cubic foot. The Dust Hazard in Tremolite Talc Mining 19 T able II L , operations. T h e m illing process liv e mills were found to be essentially -- m e ore is shipped to the m ills in railP c a r s or tru ck s and is dumped into E ,, leading to a jaw crusher. From the " usher the talc, in m ost m ills, passes DL ST CO N C EN TR A TIO N S IN TA LC 1 Operation Dust Average Counts Dust Con (million centration Mill particles (million per particles cubic per cubic foot) foot) T able I R y S T CONCENTRATIONS IN 1ALC MINES Crushing-jaw crusher 1 20 1 4 >-J 3 76-5 46 Dust Count *ra- M;n, ( ni" 7 particles per cubic Remarks Crushing-disc or 1 22 roller crushing 2 7 9 5 Pebble milling i 32 foot) 4 2 106 61 " Upstream" of drill. Rate 1' per minute Bagging- paper I " Downstream" of drill 2 I^O 3' " upstream." Using ex 4 160 >63 haust Same as above. Breathing Bacmng burlap 1 120 level o f helper 3 73-5 Kxhaust off 5 87 s 93 Kxhaust off. Breathing level o f helper " downstream" General air cihnder 1 48 Kxhaust of dvist collector room 3 85 Same as above; .3 minutes a ft y drilling stopped 4 7 5 77 72 Genera! air stream Separator room 4 58 65 " Upstream" air movement 5 67.5 62 50' per minute 265 Same as above. Air turbu Manual handling 1 215 lent HRr c U ff w* Stoping A B Ifucking A B 90 Dead end drift 300 Just off main airway 16 Main airway ICO Breathing level driller, top o f open stope 4000 Dead end stope. No air movement 760 Top o f dead end raise 40 Bottom o f stope, drilling at top 50 Same as above 6 Top o f pile, mucking only operation 35 " Downstream" o f mucker 2 4 Same as above through disc or roll crushers, or both, be fore entering rotary or trommel screens. A fte r passing the screens, th e talc is stored in garners before the final m illing operation w hich takes place in pebble m ills. T h e final separation o f the finely ground talc is ac complished with air separators, from which the materia) passes to garners which feed bagging machines. The bagging machines utilize open top bags, or sacks, which fit loosely onto the discharge spout o f the machines. Hand scoops are used to add or rem ove talc from the bags to obtain accurate weight. The greater percentage o f m aterial is bagged in Sm ith and Leonard G reenburg 1-- W illiam Slegai, Adelaide Ross Roentgen Findings 50 lb . paper bags, whl(!eS00^ r'^ o hrsP of the larger burlap b a6s _ h fiUed bags on S " a" " ".1 w - T a b l e III . . . B Y LENGTH O l EXPOSURE r .B R O S .S 1H T A ^ W O R K E R S ^ B V J . ^ - - Cases of F ib res^ ____ Years Exposed /\ll _ WorkersNum. xammed ber Total Fibros.s Cases percent F.xposore GrouP percent *in'bardeSnce. >I n jreeccoorrdingS Ppu^lm o^narsyh gfihbtroor- sis among talc ' o f fibrosis were dis even moderate deg cases inciuded in regarded, and on y t tWs con d ltion which a marked degree w aUs ppornesethnet.in itial rrooeentggen^ su^rveyMinJ 1m94en fibrosis w as found 1 3^ ^ ^ per cen t. examined, giving according Th e distribution of Table m . to length of exposure isshowtm gd ,n It will be seen that n ocase^ _ urc_ workers with ywere all found T h e 3* cases f ,, ho had worked in talc am ong the 107 r" e" ,,vm g an incidence for ten years or longer g - v ^ ^ mQre o f rate for this g ro u p * cent. O f the 8 men em ploym ent / *9-9 P Qr more y e a rs in who had wor e * > ,,0 - . talc, 6 showed hbrosis 1,7 4 ^ ^ ^ ,s 'Petals 3* - 1 d ra rs or autom obile trucks for into radroad cars warehouse for storage. shipment, or mt milling operations. D W ,T r th v .^ m f.ifconfinl D ust control m the a hjnes and pebble chiefly to the baggmg used i,, several mills- Some control ^ m aterial transfer mills a t the crush , were taken through- points. D ust samp technique already out them ills usmg the >t the T o m ake clear the ` fibrosis-producing du cases of fibros.s, workers and m a gro P workers previously distribunon of t age in talc factory \ by the authors, is shoW" ^ oniy o .5 per cent Fibros.s was p resen t' . m ,, per cent of all carpet workers, and 4 9 P T ab le IV ,, ... pet W O R SE 5 , B' AGE r.B R O S .S IN TA LC A C C A M E * _____ ^ TalcWorbers C B ^ ^ V orkf^ described. 1 he samp locations breathing level o f t h e - o ^ tionwi where men are ,,,,,,centrations found T a b le n sh ^ t^ rh ro u gh o ut the mills, a t various I*>mtsnf [ L t| k produces con M anual handling ^ those found at centrations m exces nately> there is other operations bu , normal little manual handling during cedure. . ntb er than man- T h e dustiest P e ra f " ' r bagging where ,, a l handling, is th a t o p ^ ^ a t.on for three the average dust mills was found to be 1 J per cubic foot. iUion particles - Nl; ; , : w ^ fibu,s,s ABe ber T m Per Tned b e T c e n t Less than ao 00-19 30-39 40-49 50-59 60-69 70-79 Totals 3 exam- Nummud ber a66 _ Per cent 1 .6 1 .; nary fibn th slight ot s were dis. ncluded in . condition ey in 1940 e 221 men c per cent according 1 Table lit tccurred in ' exposure, all found ked in talc 1 incidence or more of "the 8 men -e years in ent). t talc is a ribution of .ge, in talc iet factory 1 by the .5 per cent 9 per cent RS SY ACE :t Workers With fibrosis Num Per ber cent 1 i .6 l i7 4 8.1 6 2-* The Dust Hazard in Tremolite Talc Mining L years o f age and older; while resent in 51.5 per cent o f talc J?n this age group. Kmnths after the original roentgen Jfsecon d visit was made to the same ^brfollow-upexam inationsof selected ftt this tim e occupational and medifaries were taken and chest exam.naE ,, t made. From the occupational Res it was possible to eliminate those Lho had previously been exposed to g J w p e s o f siliceous dust. In this way a m o f l Z cases showing marked fibrosis ^defined in men who had not worked m K 'ther dusty industry and whose only i i c a n t dust exposure, therefore, had to talc. irns and symptoms, hifteen o f the men Sine, fibrosis w orked in the talc m ills; e re miners. T h e proportion o f mill irkers to m iners in the entire group, how- -was approxim ately 2.3 to 1, showing ^fibrosis w as relatively more prevalent Fk ;. 7. Case 198-1. Aged fifty-four. Beg.in work at age o f fifteen. Farmer sixteen \eare; telephone linesman seven years; talc mining sixteen >ears. Complains of productive cough and ihspnea Physical examination- Chest expansion i inch Nails curved. Roentgen examination: Shows en largement of the hilar nodes, and exaggerated linear markings at the right base. There is also a fine, generalized, diffuse fibrosis having a granular appearance. wm/f- ' # `6. Case 200-28. Aged forty-six. Began working pat age o f fifteen. Woolen mill six years; talc mill ' >rker twenty-five years. Complains of cough, tness of breath pain in chest, fatigue. Pkysteal Rumination: Chest expansion i f inch, respiration 18, breath sounds diminished. Clubbing o f fingers. * ntgen examination: Shows a very fine, granular oats on a diffusely hazy background. The hilar ides are thickened. among millers than miners. W ith one ex ception, the men with fibrosis were all forty years o f age or older and had been exposed to talc dust, as noted above, for at least ten years. Thirteen o f the 18 had one or more sym p toms referable to the lungs. Ten com plained o f dvspnea; 7 o f chronic cough and 3 o f pain in the chest. In addition, 5 com plained o f excessive fatigue. O n physical exam ination, all 18 showed limited chest expansion. Thirteen showed abnorm al lung signs and 13 showed curvin g o f the nails or d ubbed fingers. In one case cardiac h ypertroph y w as observed, and in one auricular fibrillation. The general appearance o f the group struck the examiners as being distinctly dif ferent from the appearance o f the usual group o f first and second stage silicones who are still able to work. T h e latter usually present a robust appearance. A substantial num ber o f individuals in such a group are J a -JLAKV, . a,,d Leonard Greenburg i Adelaide Ross Smith ana -- , ,, W illiam Siegal, A i -Tphhe hilar nodes show in hi gores 7 an^ 9 `. ase in density, h -'1" e S ^ j a t W ^ S S S t S S ^ s * i O " shagginess ot tn noticeable. , e total group of ' Tuberculosa- In ^ (13.J per cent) talc w orkers ther*J le(1 tuberculosis; 6 (a-7 cases o f primary heal " S e c tio n type per cent) cases of ^ tuberculosis anJ w hich w ere c ent) cases the basis ot the to show chni- roentgen appe herculosis. , tally significant t d prim ary and re TThhe incidence o . nQt relmnaarrisk.ratb^l>e. :m ' ^ - " . ` l ^ n W i l a r to t h a t f ^ n d 'T 2k s= of hngers. diaphragm ,efr eaf of the elevation of ngn Qn the lcft lea* of the c o s t o p h r e n i c ^ mater,al. Boll, d iap h ragm is ram ,lar fibres,s. lungs show a hne.g v.t T h is was not the lik ely t0 Kber etT lc'w o rk e rs who sh ow case with the t overweight, bu fibrosis. N one of them to present an on the contrary the> , appearance. U w - 'S S W f c - a - - - the roentgenograms Roentge' iographtc ^ - ,, . T h e type Foentgen0gram s is of fibrosis seen n the ;ng ,n many very fine and drift ^ ^ hailness to cases an appear d glass," used m which the term & f g e s t o s is , can scribing certain cases 'lUu5trated in fro.*. twenty-nine t expansion i ,nC ' 0,,. very well be n p p '.f - ^ ,, 'u m b e r of cases Figures 6, 7, - ^ ^ there is m a d d '11 , appearance (big- 7)> dis,inctly * " d m some nodula- h might be con- tion (Fig- 9 n " d j o ) w film soft fused w ith silicosisconglomerations als (Flg. 9 and ) cases tend? to be non *4> base, finely nodular ti .X u gh ou t jeft base. is There |@ is also an area s ? interspace C TTBhhe fibrosis imn on^th e trigh t side,. r^ eS rn rU an d b asesasseen if 221 cent) 6 (2.7 1 type cases of the - clinimd re able in ind, in *. The ibercu- ,n working years; carrepair man a. Physical :s, rcspiraamtnaiion: 'hroughout e left base, eura at the ows in this set! density interspace {suggesting The Dust Hazard in Tremolite Talc Mining 23 H oer cent) is slightly higher than is - K s t industrial groups the average j for this condition being about K t Among the S individuals wkh S l y significant tuberculosis 3, be , the ages o f thirty and fifty, showed nal lesions; one, forty-five years of age f e d moderately advanced lesions and sixty-four years of age, showed what fcntVpreted to be far advanced atypical a X f s i s . Among the 18 cases of fibrosis exposed only to talc clinically sig- f i l K tuberculosis appeared to be a comf t i n g feature in 3 cases (16.6 per cent). bMK a lc group ofAtamlcoswt oinrkteerresS-t,lnntgerfeinsdtm," gg ^use, to these investigators, ,t was new was the presence in 14 instances (0.3 Pcent of the 221 talc workers originally ntgenographed) of what appeared to be of opaque material on various pleural surfaces. These deposits, or plaques, ' ire seen on the visceral pleura, including he region of the diaphragm, and occasion- VHrJ Pig. II. Case 201,10. Aged forty-nine. Began work ing at age of sixteen. Farmer seven years; talc mill laborer and foreman twenty-six years. Complains o f productive cough, dyspnea and fatigue. Physical examination: Chest flat, expansion limited, dullness at apices, otherwise hyperresonant. Rales through out, most marked at bases. Respiration 22; pulse 1ifi Heart negative. Clubbing o f fingers. Roentgen examination: Shows a fine, soft mottling over both lung fields, more pronounced at the bases. In ad dition, in the third left interspace near the pe riphery is a round homogeneous area o f increased density about 2 cm. in diameter. Fic. 10. Case 197-8. Aged forty-nine. Began working -Ail age of foorteen. Talc mill laborer thirty-five years. Complains of dyspnea, pain in chest, fatigue. T Physical examination: Chest expansion i f inches. PgNails curved. Roentgen examination: Shows diffuse finely nodular fibrosis with soft shadows suggesting ^bilateral, clintcaiiy significant, apical tuberculosis. ally' the pericardium (Fig. 8, and 13 to 17)Lateral and oblique views indicate that their location is definitely' at the periphery of the lung, not involving the parenchyma (Fig- >7)- . 1 In size the plaques vary from a single, linear-appearing deposit of a few centi meters in length in the region of the dia phragm (Fig. 8 and 12) to massive deposits hizarre in shape, extending over a large part of the lung fields (Fig. 14, 15, ih and 17). They are characterized not only by irregu larity of shape, hut by marked irregularities in degree of density also, and by the sharp ness of their borders. In this series of films the development of these plaques can be traced from small, light, scarcely noticeable deposits to the extensive opacities de scribed. a4 . > . W illiam Siega!, Adelaide Ross Sm ith and Leonard G reenburg January, 1943 An analysis of the group o f H talc workers who showed these deposits revealed the follow ing fa cts: T h e ir ages ranged from thirty-five to seventy-seven years and their exposure in the talc industry from four to fifty-tw o years. Ten were mill workers; 4 were miners. O nly one individual gave a history o f having had pleurisy. None had had empyema. In 5 instances no lung p ath ology other than the plaques was noted. A m arked degree o f fibrosis coexisted in 7 cases. Evidence of clinically significant tuberculosis w as seen in one case and o f prim ary healed tuberculosis in another case. N o sym ptoms or physical signs attribut able to these deposits could be identified, Fig. 12. Case 200-20. Aged sixty-three. Began work ing at age sixteen. Fireman three years; farmer eight years; talc mill laborer and repairman thirty-nine years. Complains of dyspnea and fatigue. Phyttcal examination: Lungs hyperreso nant. Heart slightly enlarged to left, rate irregular. Clubbing of lingers. Roentgen examination: Shows deposits of opaque material on the left diaphrag matic dome; marked emphysema at the left base. Both lungs show diffuse, granular fibrosis with ir regular patchy shadows at right base and left imd- Iung field. It should be noted that roentgen appear ances similar to the plaques herein de scribed were apparently seen in C ase 1 where mention is m ade o f areas o f increased density restmbling lipiodol or calcific de positsin m id-lung fields. Sim ilar appearances h ave also been noted in another group o f workers who were exposed to talc dust m the making o f material for electrical insula tion. So far as can be ascertained, these de posits bear no relation to any history of previous infection sinee they occur both with and without such a history. N or are they necessarily associated with other pul monary pathology. The underlying lung tissue may or m ay not show fibrosis. There is no associated enlargement o f the hilar nodes in cases showing plaques w ithout fibrosis. UC. 13. Case 201-5. Aged fifty. Began working at age of fifteen. Farmer seventeen years; repairman in talc mill eighteen years. Complains of cough. Physical examination: Lungs show diminished breath sounds throughout, especially on nght. Heart: systolic murmur at apex. Pulse 120. Club bing o f fingers. Roentgen examination: Shows a soft, diffuse, very finely nodular fibrosis throughout both lungs. In addition, there are irregular, sharply defined deposits o f opaque material in both middle and lower lung fields. (Lateral and oblique views show that these plaques are located near the periphery.) There are similar deposits on both diaphragms and in the region of the right spinal gutter. Vot. No , since in the gri signs only occui whom there wa> parently the pi process responsi symptomless. Fibrosis. The study was cha scribed, by a granular or not! be more market bases. Dreessen tion somewhat of tremolite tab graphical area, reported was m Fic. 14. Case 196-. at age of fifteen, railroad four ye years. Nocompl. expansion i } inc Curved. Retnfge pears to be an deposit of opaqt Stereoscopic vie\ i Periphery, prob; th a t the lung be fibrosis. The righ w fibrosis with Interspaces suggi