Document VGNvpgk0N9Dxk8rO9BLxwN0kK

SfcW t 3<VM3J^J,,;TMTf -a**l;.. . *,*. % ... , THE CAUSATION OF PNEUMOCONIOSIS* Philip Dsmxxa, From, tin Department of Industrial Eygienc, Barnard School of Public Boaltk, Bolton, Man. t!UD< 5S ?> ' sai^p??*3ji v*ijg*iJi cstHna f iirtim :*.j *** ) - ..- y rF'W^ -* <3$: - -S--8"S5^3s. **7?* i.?*S.*r . 3 f: ? & * -... ar, j . -TT v* r .. . 'A**-*^**'*\V'*1 rj; j --, ',.'.,'. --?*TJ2JJ1* C'* 4* jTriSgzsr &7viJ*&s+*` *h?4- !! $ sa v.-x ji! __i'' isKn/'f V ; "?I T-WRRTT. are four different types be small enough to float about in the reaction produced in man by air and be carried by rather slight air * the inhalation of dust. The currents; otherwise they cannot be in first and most important are the haled. such as silicosis and The modem word, pneumoeomoatt, cause specific lung is a shortening of Zenker's original often are followed by pnaumcmokoniooit. Zmrikmr (l) de pulmonary tuberculosis. The second picted hmgs definitely damaged by type of reaction is caused by toxic dust particles, but today pneumoconio dusts like lead, cadmium, and radium. sis is generally used to describe any A third type of malady follows the lung which has been dusted to more inhalation of finely divided metallic than the normal degree- there need fume particles such as zinc oxide and not necessarily be demonstrable hmg is known as metal fume fever. Fi pathology. SOicosia, asbestosis, aa- nally, the fourth reaction, allergic in tbracoeis, anthraco-eilicosh, and simi character, is caused by breathing or* lar terms indicate the different ganic dusts such as pollen and certain causative agents (silica, asbestos, sad types of pulverized wood and flour. coal) in various kinds of pneumoconio In all four instances dust fahttlntim sis. can be the sole cause of the disability The International Silicosis Confer but with the toxic dusts characteristic ence in 1930 (2) defined silicosis as a. reactions result from swallowing as ``pathological condition of the hmgs well as from fahiwtv The latter due to the inhalation of free rfHea rants, however, is much the more im (SiO*)". The Anwnwin Public portant. Health Association (3) described it aa In the present instance we are con a "disease due to breathing air con cerned only with the pneumoconioses taining silica." Sayers and Jones (4) which result solely from the action of state that "from the viewpoint of inhaled dust upon the lung tissue. * Of etiology, the harmfulness of a given necessity then, the dust particles must dust containing free silica is directly * Received for publication July 14, 1838. Baud before the Harvard Uuivenity Tercentenary Celebration, 1638-1938, By peeium an "The Environment end its ;ect* upon Men", Harvard School of Public , Boston, August 27, 1936. influenced by the number of juHt*"1-- of free silica less than 10 microns in diameter that it contains". CoIIis has claimed for yean that free silica, es pecially quartz, was the all-important m ~\ BB 0020153 l _.__ _ . migsk-ifti- Wm -- j.- ..;5s3seEit=rse3j .V. iifinTC' ` ~ .2 'J'Q * < THIS DOCUMENT WAS NOT A RECORD;. OF V. t *J . PPG IT'S I.N...DUSTRIES, INC. DID NOT COME FROM FcIiiLEcqS AaNwDn rC.AANNNNOOTr BBEE AAUUTTHHELil II iCA * CD BY `PPG INDUSTRIES, INC. 2647 vcL 18, no. S] CAUSATION OF PNEUMOCONIOSIS 525 r' jr. In summarising bis South opal, which is non-crystalline, have rican experience, Watkins-Pitchford not as yet been appraised hygicnically (5) wrote in 1927 that dusts other than and there are no statistical studies to alien could "give rise to such non- show the relative potency of the vari permanent and relatively hannlww ous forms of pure silica. conditions--one can hardly call them SUicaia.--Silicatosis is a word sug diseasea--as anthracosis, aluminosis, gested by Badharn (7) to describe a siderosis etc". lung fibrosis caused by dusts in which in figure 1 are shown data from and not free silica predomi Collis indicating the etiological im nate. The distinction between free portance of free' silica. The U. S. and combined silica is best shown by a Public Health Service's data (6), simple example: A granite dust (8) occupation HMT Grtnours (OhtfftoH) Gfi/miTE-amzrs (/fc. mnF KH.) POTTCF3 conc-n/n/no qutnerz content of oust 50 >ee% """a.* Cortmim * * PEKCENT D&TTtfSRON PUUKMUf TVBg/KWOais l,"BI -77WS% | **.7)5 | 3.0%. ^a. 1---aftwtaiayfrnw. piliwiiiMytalMwiilnAm *~l-- (AfterCoOis) shown in table 1, emphasise still further the importance of free silica. SiUca.--Silica occurs most cammanly as the mineral, quarts, which is a natural contaminant of moet ores, occurs in many rocks, and is found in a fairly pure state as beach sand, chert. Hint, sandstone, gritstone, canister, quartzite, and jasper. Quarts is a hard crystalline mineral which is weakly birefringent, that is, its two indexes of refraction are near together. Chemically it is very inert and inactive. In fact its hardness and inertness are the two properties which make it especially useful in industry. Other varieties of pure silica such as might have the following mineral composition: rwnm Feldspar (orthoelaee).... Quarts................................ Mica (mommta).............. 100 Chernies] analysis of this 'granite would give the following result: 50, (total).......................... 73.95 AlfOfe w ,,,**,*** #*,* a e 14.80 miAtVAgn 100.00 THIS DOCUMENT WAS NOT A RECORD OF . ------ -PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED i BY PPG INDUSTRIES, INC. > 2 o i~! I to I J to I o| 1 oi I to I 2i J utl j yi I ' i-i TABLE 1 BtnnuaT or th* Biz Dm Broom or too U. 8. Poouo Haauni Slavic* Bhowimo too Dost Comobhtutiom, Coufomtio* in i KumiMa Haiabd* untTir itaiub im com oi riincui mb even coot BtuVrMnsA*O**B- ABBOT cun MICA (BOABIt) oranoBiucmvnei ocniMf 1i iioni oc iaiabb vmn eoaMfiom u oMiim tm am mac Granite cutting: Hand-pneumatic tool operaIan.................................... . Burrace-machint operttort, eta.................................. General tlr.... ............ . Lea then genertl dr............ SB SB SO 9 Great exeeu of pulmonary tubereuloata after 18 years or more SB Balance mostly com bined allloa exposure; ellleoala In from 2 to 10 year*. Slllooala after pro* longed exposure; no excess of tubereutoefa Negative except for occasional nondlaabllng tilleotli Anthracite cotl: Rnnk drlltan.......................... Miner* and miners* kelpera.. 89 233 si l.S Bllleeoua rook Carbon and inorganie matter /Uflg- wm Data InaufBelent; other atudla ehow severe haiard Dyspnea and other algn* of pneumocooloele; excea rickna* from reaplratory eondltlone; exeeu mortality from In fluents, pneumonia and poaalbly luberoutosla Bituminous eoal: Rock driller*........................... Loader* and machine men... 7B 11S 64 Bandatone l.S Carbon Data Insufficient;.other atudlee Indicate aver* haiard Qenerallied fibrosia chiefly linear In eharaeterj exeem mor tality from Influents and pneumonia demon t..........._______......... SB Cotton-cloth manufacturing... * Silverware manufacturing........ MunlolpiK ******** *A(ter Thompson, it al. 7 S 4 e- Primarily lime t 1.7 t Vegetable and illica Metal and other Hot determined Some early pneumooonloala) exeeu of disease of upper respira tory tract and of Influents Negative Negative Negative .u r *oL It, me. 8] causation of pneumoconiosis Recently Jones (9) showed that i there is a really high silica content' cite was the outstanding common and "we believe that in the absence of mineral constituent of a considerable the silica factor there would be, under series of lungs he analyzed. Seriate modem mining conditions, no serious is a variety of mica with the formula degree of anthracosis...." Men who sO*3AliO>`6SiOf2HiO. Its occur were engaged in trimming coal ships rence m nature is widespread but the with virtually no quartz exposure but quantities actually found are much undoubtedly with very heavy dust less than those of quartz. It has not exposure, showed some fibrosis but it been shown that seriate, without was not considered disabling (11). quartz, will produce silicotic pathol The study made by the U. S. Public ogy; all investigations along such lines Health Service (12) in the anthracite have been negative. mining district of Pennsylvania adds Asbestos is the only silicate at pres much weight to statements quoted ent recognized as causing pathology from Cummins and Sladden, namely, which is definitely and distinctly dif that the harmfuiness of a coal dust ferent from that due to silica alone. varies with the silica which contami The condition known as asbestosis, nates the coaL like silicosis, predisposes to tubercu TTalriana considered that coal dust losis but to a much less degree. Since, might even reduce the severity of a however, asbestos is handled by far quartz dust exposure; he suggested fewer persons than are dusts contain actually blowing coal dust into a mine ing free silica, asbestosis is much less with high quartz content as an anti common tiT cnit-inri* dote for the quartz dust (13) but no f Asbestos is not a true mineral but is serious attempt apparently was ever name applied to any mineral which made to test the validity of Haldane's is easily separable into more or less riaima. The recent statistical analy . flexible fibers. Li this country, the sis of lungs autopsied in the Pittsburgh commonest asbestos is the fibrous va district (14) shows beyond doubt that riety of serpentine in the form of the city air, contaminated by an unusual mineralchrysotile,3MgO 2SiOs-2H0. amount of coal dust, does not produce Other sQicatea such as tale, 3MgO- a dia^Ming fibrosis. Many of the 4SiOt*EsO, which resembles asbestos lungs were markedly pigmented but chemically, shale, kaolin, Al*Q,-2SiOi. the pathology found was not, in gen ZH0, feldspar, and pure mica have eral, significant. been studied in both the field and the Calciumand magnesium carbonates.-- laboratory. The pathology they pro These substances occur in nature as duce is much less significant than that the minerals caltite, CaCO*, magne from quartz and the fibrosis rarely is site, MgCO*, and dolomite, CaCO*- disabling. MgCCV Limestone and marble can- Carbon.--An extensive examination tarn high percentages of caldte while of coal miners' lungs was by the bulk of the rock from which cement Cummins and Sladden (10) as the re is made consists of these carbonates. sult of"which they wrote that "coal AU three minerals are a great deal more is only retained in large amounts when soluble in water and in body fluids than THIS DOCUMENT WAS Y-nr * ' PPG INDUSTRIES iNr nt ~ CTM OF it's Files and cannot rf1?itC0M: FRQiVi ~ BY PPG INDUSTRIES, ,NC AUTHwriCA7-EO 1 ... 5 * . i.V. . ,v i -* * '. i r M .-inur * iqrTif'-.-- A .i ? sv ***&. r-- n i; T-. =2 R.. i ja *to *-** S .to* -9J -"* -< '*7 AS,. *5* :: - . . r.n9&i?r` . : .vaflhr V- ,~~u .?.*: tfdaear .-r'*. L. jrf.-S-r i ;v f 7*! * ?T- ; #S#S5Ep3pSg>-^` -:^1- > -; '., vi*`'*1>t *rI ;-; v*rJ*i * : - j. : :. tV, . .:;: :<.* $: : 1 i&:* ' >Y? ;; ? ^ `V..: --i 1 S.-tiS" - ' *,r -** *! efe#- \ v: jsr v.s* * : r?*-'* .;i i ^ * ^ * f'7 **&.- - , .. .. \` . j Wfxe*" vfv* ': ii_tr fS, . -o :*&* '- .*!**? NJ is quartz. Furthermore the solubility of all three substances increases greatly if the solvent is saturated with carbon dioxide, & condition which occurs in the hmg fluid which wets inhaled dust. . The several studies which have been made on calcium carbonate dusts indi cate that the dusts are not harmful probably because they are so readily dissolved (8). Oyprum---This mineral, CaSO- 2H*0, is very common and is mined and milled all over the civilized world. It is an essential ingredient of ordinary plaster and is now used extensively ss a wall board. When partially de- hydrated it again takes up water readily, but in neither that state nor as the native substance has it been shown to be harmful (15). It is an interesting fact that pure limestone (quarts free), dolomite, and gypsum are recognised universally as the dusts safest (hygienically) to blow into soft coal mines to prevent explosions. Iron Oxide*.--The mining of iron, next to coal, is perhaps the mining industry in which'the greatest number of men are employed throughout the world. The ore generally is hematite, Fe*0, but other oxides, and sometimes th milfid, pyrites, FeSt,arehanrilad on a considerable scale. As a result of the improvements made in machine-tool steel, it is possible today to aee iron dust created by work an lathes, drills, end the like. Yet there are no data to indicate that iron, in the absence of silica, causes pathology in any way comparable to However, hmgs which have been heavily dusted with Iran in any form are generally colored distinctively and were called by Zenker (1) tiderotic. Estimation or Dust Extosubx- ; The effect of any inhaled dust varies more or less directly with the duration of the exposure, the dust concentra tion and the volume of air breathed. In the case of the gas, carbon monox ide, our knowledge of the relationship of these factors is sufficiently exact to permit the use of a simple rule (16) for predicting the effects of breathing various gas concentrations under vari ous conditions. Unfortunately, one cannot estimate or predict the severity of dust exposures with any such nicety. In cases where men work for a num ber of years at different j be with dif fering degrees of dustiness Bloomfield and DallaValle (17) compute exposures by averaging dustiness in these various jobs over the total period in question. In their anthracite coal dust study they found that computations so made agreed well with the results of the phys ical and x-ray examinations of the men. A typical example of their method of computing dust exposure is reproduced in table 2. The advantage of these estimates lies in their simplicity and the fact that they have proven useful in corre lating dustiness with physical examma- tiona. The error in such calculations is that the effects of dust do not vary . exactly, but only very approximately,, with the dust concentration and with the exposure. Thus, Mavrogordato (18) writes that "Lesions of silicosis in a mild degree can be produced in an by 30 hr. exposure to intense dust clouds, and one is inclined to suspect that it is intermittent exposure to relatively dense clouds that is the deciding factor in producing the dis ease in susceptible human subjects." These momentary excesses of dusti- *'K. 7 vT*- i.......... ' ':D WAS NOT A RECORD OF ^ T 0020157 | 2651 ' . -JJ? Jh FOS7m1E^' INe'DID N0T C0ME FR0M : * rr S FILES AND CANNOT BE AUTHENTICATFn : S PPG industries, INC U,HENT,CATED ---*1 CAUSATION OF PNEUMOCONIOSIS 529 Mm.TTOgorda.to named dust floods, Bloomfield and DallaValle's calcula tions of necessity ignore dust floods and use only figures of avenge dusti ness. The Value of Dust Samples The purpose of dust sampling is to make possible the control or elimina tion of dustiness rather than to obtain a precise measure of dust concentra tion. Conditions may vary greatly almost from moment to moment and aids of dustiness and is in reason able agreement with Mavrogordato's "figures of merit" as obtained fay konimeter samples. A great deal of time can be saved by ignoring samples which are obviously too dusty--it is aa well to take the sample fora matter of record but it is absurd to work long over it if it is cer tain to be vastly in excess of the ob jective. Mavrogordato dismiswes such samples with the laconic symbols "T-M.C." (too many to count). TABLE 2 Example r Method Used nr DEtmurctiMO as Emplotxz's Total Dost Exrosuas* -- 4?M11W eoMnomnmtuunnoMe Himax mv mcpiii fttfiCBKftfM* foot Slate picker (dry breaker)........................ Batcher (dry mine).................................... Mule driver (dry mine)............................. Miner'* laborer (chamber)........................ Miser (chamber mining).................. . :on foreman......................................... 2 2 3 3 3 5 380 780 71 142 n 213 480 - M40 480 7200 7 38 ^.otala...................................................... 30 8780 0790 millions of particle years per cubic foot __ .... ,, , . 1 ' .......- 328 millions of particles per enbie foot 90 Tun * After Bloomfield mad DmllmVmUm. only occasionally are they reasonably constant during a working shift. In general, then, it is advisable to give the results of the final estimate with an indication of the expected variation. "Thus, as a means of classifying proc esses according to their respective health hazards, it appears to be un necessary to arrange them in concen tration groups closer than 100 per cent, 0 to 5, 5 to 10, 10 to 20, 20 to 40, etc." (S). Such an arrange ment is consistent with the few aTTuriwtn data we now have on stand- On the other hand, it is well to have records which indicate that the en vironment is as dean aa is desired. In * our own experience the ignoring of such samples has raised difficulties in prov ing in court that adequate dust con trol had been enforced. . There is no doubt whatever that, In the United States at least, dust samples now have a very definite place in depicting work ing conditions to compensation boards or to a court. Under the circum stances, it is very unwise in making surveys to ignore the dean places. . . N:... 8y INDUSTRIES, INa mHEm`CAKD 355^ il -p taafi \ 530 JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [OcL, 1999 Methods ef Sampling the sake of the legal prestige thus Dustiness is given gravimetricaHy gained has its drawbacks. We know if the dust is to be determined chem of one case where a gasoline motor- ically and by counts if the chemical driven generator and electric pump determination is especially difficult. mounted on a mine ear and hauled by Thus, lead is always recorded in milli tractor, with three men in attendance, grams per cubic meter but dust which resulted in obtaining only four sample may cause silicosis is given in particles in one day. per cubic foot or per cubic centimeter. In South Africa where dust sampling Sometimes one may wish to convert has been done on a scale far beyond one set of readings into the other. If anything attempted elsewhere the the dust particles are perfectly uniform konimeter and sugar tube both have and of definite shape such as spheres been used. In England great hopes or cubes and of known composition the for the new thermal precipitator have conversions can be made with pre been advanced but the results pub cision. In such a case, it does not lished so far have added nothing sig matter how dustiness is recorded. nificant to the data already available But in practice the dust particles are from methods which are less accurate. never uniform in size and rarely in In Australia several different instru composition. Conversions are, there ments including Owens' counter have fore, apt to be miaWrfing. For prac been used while the results coming tical work, 1 mg. of fine quartz as from Germany were obtained by filter collected by the impinger contains 300 methods and by a modification of million particles (by the light-field Owens' counter. counting technic). In our own studies we use several A great deal of energy is being different methods according to the wasted in deciding which dust samp problem. There is every reason to pling method is best The rapidity encourage rapid methods which are with which newmethods are appearing, particularly applicable to routine con each claiming unusual points of merit, trol and to discourage the widespread r: indicates that standardisation is un use of the impinger technic except far likely. -An international agreement occasional check-ups. The impinger an a reference standard would be wel baa little to recommend it in control comed by all working in this field but, work while a light portable instrument, at present such an agreement seems to such as the konimeter, has already be far off. proven its value in practice. In the United States the impinger technic is most used, largely because our only extensive field data come CoMPoeraow or Air-Floated Dukis from the Public Health Service whose It is rarely that one meets exposures workers favor this instrument. If one to pure silica; generally the dust is a wishes to compare his results with mixture of which the original compo those of the Public Health Service he sition either is fixed, as in granite, or * must copy their technic. But copying variable as inmostfoundry and mining' the Public Health Service's technic for operations. But the .composition of N ATT- "rr ' US; Tins DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED i7. IS, no. 2] CAUSATION OF PNEUMOCONIOSIS je dust breathed from a mixture is seldom the same as that of the parent material. If a dust arises from the grinding or comminution of a comparatively pure substance, such as beach sand, the resulting material must have sub stantially the same chemical and mineralogical analysis in all stages of particle subdivision. But If a com- frequently sample and count air-borne dust by the impinger technic and then for chemical and mineralogical anal yses take samples of material which has settled on rafters which will have a quite different composition. To make bad matters worse, samples for mineralogical and chemical analysis usually have not been graded into various sixes. 05 0607 oe OR IO II 12 IS .4 IS IS 17 IS IR 20 2l 22 3 24 120 YEAR" m 130 E)2C__ ClIO ftoc fcRO n D80 Q7D ^60 e" 40 -J *130 Cac tooL Fio. 2.--Dmt control and silicosis in Sooth Africma gold Mavrogwdato). (adapted from plex material like granite is ground and the dust then scattered in the air, samples of different particle size will have very different composition. Many examples of the changes in composition of airborne dust can be found in the literature to prove these statements but it is interesting that the facts generally have been ignored. Thus, in this country, investigators Jones (19) has given indisputable proof of the carelessness of which most of us have been guilty in recording the composition of air floated dusts. In support of Janes' contentions an in teresting example is given by Drinker and Hatch (8) for foundry dusts. "A good molding sand is made up of about 80 per cent quartz in the shape of coarse particles; the bulk of the re- r*-[------ : .V. - ^ - V `tw.asgJh v i ^ jp` `: - - wi;;. 74- \5C.( *>_' 'Bfaf-Jpi Vvl-." e 21 * %.#I1 T`- - ir. ' fiSr . M_`w *Vt.. .r --' VV: - ^ tl./ THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM ITS FILES. AND CANNOT BE .AUTHENTICATED BY PPG INDUSTRIES.4NC. IJJBJ0 20160 J .t. ***:+&*:& SSgk s* r-' i % $ sftsa jku:*! tr^tP:*-**t*V-. * - 3 __ l r>- `-Tr 'w * 1 * St; S*5 *2?** $ . *rr? 'Hi S ir 3 q J*r:? ' -5J -\ f. **t*''*TJ .\J l -;.. Vv>*-u>ws- .. vr; a s. w JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY (OcL, IBM morning material is day in the form of fine particles which coat the coarse quarts grains. The chemical com* position of the finer fraction (say below 10 microns) of material in foundry sand is markedly different from the composition of the coarse fraction." Thus, the original material contains about 76 per cent quartz, while par' tides above 10 microns have 85 per cent quartz and those below 10 mi crons have only 19 per cent (see table 3). Under the present methods of estimating dust composition and dust hazards a large error obviously would be made by assuming that the changes in the, composition of Barn granite, of 35 per cent original quartz composition, and of various cod-silica mixtures take place on settlement in air. Obviously, changes will occur (probably great changes) but they have not been measured as yet al though we have all welcomed the figures of reasonable dustiness sug gested by the U. S. Public Health Service for the two industries in ques tion, granite cutting and coal mining. Their analyses were all made from samples which had settled out on raft ers, and no samples were separated into various particle size fractions. TABLES Composition or Coaxsb and Fmx Fractions or Unuszb Foowx>*t Saxo (Coxranfcra Natcxai. Boko) --. MKMRAMSTWM* Tottlauapla >ife <M Combustible............................................ HQ soluble................................................ HSiF soluble (day)................................. Residue (quarts)........................................ 2.3 5.5 1S.0 78.3 0.7 1.6 12.7 85.0 12.7 30.5 37.5 19.2 Total....................................................... 100.0 100.0 100.0 original material represented the fine air floated dust. Another example is given by Jones (19) from the Smith African "banket" --large crystals of quartz hdd together by fibrous seriate. Hi figure 3 tie illustrated the changes in dust com position which he noted as the dust was allowed to settle, as it would in practice. Obviously, the quartz con tent decreases as the seriate increases. Janes remarks that "when a wall built of quartz boulders is pulled down, the bulk of the dust comes not Horn the quartz boulders but from the mortar." It would be interesting to know what Particle Size It is well known that in silicotic hmgs dust particles under 3 microns vastly outnumber those which an larger. It has been alleged that the respiratory mechanism, the hmgs, and the phagocytes are mostly responsible for this size grading. However, it is easy to show that the size grading is done in the air before the dust is breathed and not later in the human body. That is, we find an exoess of small particles in the lungs simply because that is the way that they oc cur in air. It is physically impossible for any but particles below 5 microns NOTE:'-'..... : NO\\r\T THIS DOCUMENT WAS NOT.A-^ECORO OF i - PPG INDUSTRIES, INC. DID NOT COME FROM -'-^"g7-7 IT'S FILES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. voL It, no. 4] Causation of pneumoconiosis S3& remain afloat in air long enough to carried about by gentle air currents ad to be inhaled. It is perfectly true that the alveoli are large enough to rarely remain in air more than mo* mentarily. Bloomfield (21) has re corded hundreds of measurements of air floated dusts. His average sixes t fc\ I . r/c*.7^7"' '&r' *a #s G"' -* /*> o*v O * rt ft *0*o /7 * *7 nb: * Vm.u * >. . a , * **' *.<. *Y* , &.>_ C # So# ** ^ `r '\Q - * ** # f f # ~ ir * (a) ft; # I %* I . *' \ fti, *i* * .*4 * ( *# *. I l|ft* e at* * * \v * s'-'-t. *. .7 W * 4 "* * * #> ** f# **7/ - -S'* */ ft * . > -.? Vu'lis' \\\\4.t*..(.*>1.*..'*....--.*...'*1-*. Nl.v (e) (&) Fiq. 3.--Sketches illutmtiiig the increase in the ratio of fibers of aencite to quarto part.icles at * m *t * i *_ e l * " _ A - - * -- - -- -X aAlrii vntffto js a A nMre U minutes blasting; am Metallurgy-) admit, particles 100 or even 200 mi crons in length and that such particles are occasionally found in hmgB (20). But the reason that they are found in lungs so infrequently is that they are all of the order of those found in lungs and in phagocytes. Gy* and Kettle (22) showed that colloidal sfiiea was extremely toxic and that it could initiate fibrosis. It - K>v-lSffite 4^ %T - -r-^ ./ Ss&a&f. . - ' ' V%S? SfflgS xs* r3P^f' ft-WTi-*. .n 5e.T3Tf-fc!'vi . ft 2 ' r , -s iiVSSf. ^Ti asar i. . 'nf'^SlSN^g * - :i V* -> ' '^0 ITS fS^IV8ETLC?ME FR0M BY PPG INDUSTRIES IlC. lHENTI?AVE0 $ -U` 7"bB*00 20J62_| poi. 28, mo. 81 Causation of pneumoconiosis 533 remain afloat in air long enough to axried about by gentle air currents d to be inhaled. It is perfectly true that the alveoli are large enough to rarely remain in air more than momentanly. Bloomfield (21) has recorded hundreds of measurements of air floated dusts. His average sizes yr9 . m.J* /**..*; *# o X*- *; v. 4-,a -*' . 'f'.X'* '}\ - \s : ^X'i) : 9.r a \ * O-* V o ' a \ Vo*.-*:~ '.*** - tr.V -' .: " - -i j^SmmS: "* W _*7 *< ' s&Tl i* W-' 4 sr^,. a-'v Fio. 3.--Sketche* ilhistratiag the inenue in the ratio of fiber*,of eerieito to quart* perticlea at different periods alter bleating in a Witwatemand gold mine, (o) about 15 minutes after blasting; (6) about 1 hour after blasting; (c) about 2J hours after blasting; and (rf) aboutSbom after blasting. (After Jones, courtesy Inst* Mining and Metallurgy*) admit particles 100 or even 200 microns in length and that such particles are occasionally found in lungs (20). But the reason that they are found in longs so infrequently is that they are all of the order of those found in lungs and in phagocytes. Gye and Kettle (22) showed that colloidal silica was extremely toxic and that it could initiate fibrosis. It uTll ,*V. # t a e , ^-i-grgsz '-KT - *' -I'.pr ^ THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICA7ED BY PPG INDUSTRIES, INC. |_BB 0020163*7 ..* L iSWSSE?- iwikiki xl-r'rj'pC^^Z-: p*f V. *?** - ,.*i.rj^.i ^^*yrTtS5^^y.'L-< * .* ti t?J &&8&eS&msi f.y: p y.;;' JOURNAL OF INDUSTRIAL HYGIENE AND TOXICOLOGY [Oct, We is claimfed occasionally that the dam age done by quartz particles is due en tirely to those which approach the colloidal in size. Usually particles possessing colloidal as distinguished from crystalloidal properties are con sidered to be less than 0.1 micron in size. All colloidal particles are so small that they can be measured only ultia-microscopically. There is no*evidence indicating that appreciable or significant quantities of ultra-microscopic quartz can be made by any known process of grind ing or comminution, including blast ing. In fact, the difficulty of prepar ing even small specimens of quartz below 0.5 microns is considerable. Furthermore, then are no published data indicating the relative potency of quartz particles in various sizes be low 3 microns. Under the circum stances, then, there is no good reason to blame colloidal particles as the in itiators of. the silicotic nodule when it has been demonstrated again and ftgam that such nodules can be pro duced by particles approximating the common bacteria in size. Standard* of Dugtinou Under one name or another the plant or mine manager always wants an objective for his dust control pro gram. It serves no useful purpose to evade the issue on the ground that precise figures are not available. Probably they never will be. The practical man argues, very properly, that if dust is the cause of silicosis there must be some degree of dustiness or of air cleanliness which is safe. Having been told that silicosis is a disease caused by breathing silica, the practical operating man naturally ex pects of the physician or hygienist some objective of dr cleanliness, call it by whatever name one likes. In this-country the U. S.- Public Health Service studies have furnished the only published data we have from which we may suggest dust standards. In the case of Bane granite it was pointed out that a dustiness of 10-20 million particles per cubic foot was reasonably certain not to cause dis ability. The coarse dust, in this case, contained about 35 per cent quartz. In their recent" anthracite coal study the Public Health Service found* that counts of 50 million per cubic foot, with 5 per cent .quartz in the coarse dust, seemed safe. In the case of pure quartz Cum mings (4) suggests a figure of 5 mil lion particles per cubic foot which is not far from the South African figure of 1 milligram per cubic meter (fig ure 3). We have then 50 million for dust with less than 5 per cent quartz and 5 million for pure quartz. It is very questionable if one has any right to interpolate for the quartz percentages between 50 and 5 but the figures certainly invite such inter polation. These standards do not answer the question of the plant which dust of no proven pulmonary signifi cance. What standard should the manager of such a plant take as his objective or need he take any precau tions at all? We cannot give him any standards but we can only suggest that he investigate one of the many plants which has reduced dustiness without waiting for any physidiogical justifica tion. Generally the manager and. workmen of a clean plant will upholdeloquently the advantages' of dust ' control. t rk v - -2-iLJTHIS DOCUMENT WAS NOT A RECORD OF------------------ PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOf BE AUTHENTICAT ED BY PPG INDUSTRIES, INC. *L IS, no. 5] CAUSATION OF PNEUMOCONIOSIS 535 V It is only in South Africa that dusti Silicosis and asbestos axe definite dis ness and silicosis have been correlated eases; in anthraco-silicosis and various routinely over a considerable period. silicatoses one sees modifications of There they realised at the outset that normal lung conditions. The effects dustiness would not be controlled of carbon, or carbonates, of gypsum properly unless measured and re and of iron oxides are also discussed. corded routinely. Concerning the re Methods of estimating dust ex sults of their procedure, Irvine (23), posures of a workman includes the Chairman of the Miners' Phthisis taking of dust samples from the work Medical Bureau in 1934, stated that place and interpreting the results dur "No `New Hand Miner' who has en ing the man's total period of exposure. tered the industry since August, 1923, Errors which have been made from he. 10$ years ago, has as yet contracted estimating the composition of dust silicosis. These facts demonstrate from samples which have settled upon that the engineering and medical rafters instead of using samples taken measures which have been directed from the air, are emphasized. against silicosis have achieved a very Permissible dust concentrations significant degree of success." It would need not exceed 50 million particles be hard to devise a more eloquent or per cubic foot for dust with very low complete proof of the advantage of dust quartz content or 5 million for pure sampling and of dust standards. ' quartz. In defense of the use of Suuicabt standards of dustiness the experience in South Africa where such standards The various pneumoconioses and have been applied successfully for 'heir causative agents are discussed. many years is cited. BIBLIOGRAPHY L Zeksxs,F.A.: UeberStaubinhalationskrankheiten der Lange. Deutach. Arch. I. klm. Med., I, 116 (1867). X International Labour Office: Silicosis (supplement). Geneva, 1830. 3. American Public Health Association: Report (joint) of the Committee on Pneumoconiosis and the Committee on Standard Practices in Compensa tion of Occupational Diseases. A. P. H. A. Year Book, 1833, p. 100. 4. Saranac Symposium on Silicosis, 1835. Employer*' Mutuals, Wausau, Win* 1836. 5. WaTxnm-Fmmroai), W.: The tflieosis of the South African gold mines, and the changes produced in it by legisla tive and admiaiatrativeefi'orta. Txu Jomu, 0,109 (1827). 6. Tnostrsow, L. R., xt an.: The health of worker* in dusty trades. General statement end summary of findings. U. S. Pub. Health Bull. No. 208 (1833). 7. BanHan, C.: An investigation concern ingventilationand the sandstone dust present in the sir of certain sewer tunnels under construction at North Shore, and in other sandstone work ings. Kept. Dir.-Gen. Pub. Health, New South Wales, 1824, p. 52. 8. Damans, P., am Hares, T.: Indus trial dust. McGraw-Hill Book Com pany, Ine^ New York, 1838. 8. Jons, W. R.: Silicotic lungs: the min erals they contain. J. Hyg^ 33, 307 0833). 10. Comnn, S. Ib, am 8Lasor, 8. 7.: Coal-miner's lung: an investigation into the anthracotio lungs of coal miners in South Wales. J. Path. Bact., S3, 1085 (1830). U. Couza, E. Ia, am Gtlrhhtst, J. C.: , . itS THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CANNOT BE AUTHENTICATED BY PP.G INDUSTRIES, INC. * !! /s ^ $VjT ^ s-ss#' .*>!?*si . ar ' '*-:t.*O1 Bs 'L' C*JTT.VCv.'-'1VZ. . j'-.--- ... eiV* JStfaiiAL of Industrial hygiene and toxicology iocl, ism Effects at dust upon cool trimmers. This Jouil, 10,101 (1828). 12. Sanaa, R. R., rr ai: Anthraco-eilioasis among herd cosl minors. U. S. Pub. Health BulL No. 221, (1935). 13. Haummx, J. 8.: The avoidance at sili cosis with dry methods of working. J. Cham. Met. Min, 8oe. S. Africa, SO, M (1820), Abet. at length in This Jon*., IS, 77 (1830). 14. Sanrancn, lb, At.usow, W. C., Boons, C. M., amb Hattbovi, S. R.: Pneu moconiosis in the Pittsburgh district, baaed on a studyof 2^00 post mortem examinations made in Pittsburgh hos pitals. This Joua^ 17, 294 (1835). 15. BmnHLL, A. R.: Clinical investigations into the offsets of gypsum dust. Canadian Pub. Health J., 88, 147 (1934). 18. HnwDxaaow, Y., am Haooabb, H. W.: Noxious gases. Chemical Catalog Co., New York, 1927. 17. Blooioicu, J. J., ajtd DaalaVaixx, J. M.; The determination and control of industrial dust. U. S. Pub. Health BulL No. 217, 1935. 18. Mavbooobbato, A.: Value of the konimeter, being an .investigation into the methods and results of dust sam pling as at present practised in the mines of the Wltwateisnwd. S. African Inst. Med. Bos. No. 17, p. 45, 1923. 19. Jowcs, W. R.: Silicosis. Inst. Min. and Met., 42d session, London, 1933-1934. 20. Cooee, W. E-: Modern views on silieosis. J. Hyg., 35,207 (1935). 21. Blookrxib, J. J.: The aiae-frequency ofindustrial dusts. U.S. Pub. Health Repts., 48, 961 (1933). 22. Grx, W. E., am Kimi, E. H.: SQicoaia and miners* phthisis. Brit. J. Exp. Path., 3,241 (1922). 23. Ihuhx, L. G.: Miners' phthisis. J. Cheat. Met. Min. Sou, 8. Africa, 89, 304(1934). sSv < : *: ' THIS DOCUMENT WAS NOT A RECORD OF PPG INDUSTRIES, INC. DID NOT COME FROM IT'S FILES AND CAKN&T BE AUTHENTICATED BY PPG INDUSTRIES, INC, | 13 B 00 20166 | r.