Document wrMXj3BdLV2LXQq5Eqb5Gzn96

wiifl Ppoc r.-ri - jizi r'-jZ'ia&P: ' . -v * ^ - ' -' . ~-%*yr '-*Pty-iJ- _ -' '- ~js!: :. _ ' Industrial Dust ~~ "rv ' - >5-*<* *v- S`o..- 1. The literature __on hazardous ef fects of dust is so extensive that no at tempt has been made here to cover the subject in all of its ramifications, but to assemble only the outstanding data on several of its aspects. This pam phlet is intended for employers, plant safety engineers, personnel managers, and supervisors generally. The subject has been approached from the prevention angle, giving general information on oc - This pamphlet is one of more than 150 Safe Practices and Health Practices Pamphlets. It is s compilation of experi ence in, accident prevention from many sources. It' should not be assumed, how ever, that it' includes every acceptable procedure in the field covered. It must not be confused with American Standard safety codes; federal laws; insurance re quirements; sate laws, rules and regula tions; and municipal ordinances. Addi tional capias of this pamphlet art avail able. Mamher prut, 35 cents eatb. Quan tity and non-member prices on request. "limg,"*1"dust" 'and''`abnormal cond _ tion," JThe present generally.accepte - meaning of the word involves the cor cept merely of "dusted lungl^The kin of dust inhaled determines "the' type c injury noted in the lungs?"*Howevei there is' one pathological process which underlies lung disease mused by dust. This consists of a fibrosis'or* a'replace ment of the elastic tissue of the lungs by an impervious scar .. i'l a ; if stf^Hl .. 6.- Research on pneumoconioses has cupational diseases'caused by dust and on methods of control.. No reference is made to the economic and legal aspects of dust diseases "in industry and none of the uncommon 'dusts as, for instance, might be found in the pharmaceutical industry, are discussed. There is a short section on dust explosibility. . .".tr. ir -. ......... Physiological Effects of Dust 2. The inhalation of dust may pro duce different types of reactions in hu man beings: ; a. Pneumoconioses (silicosis and asbes tosis) which result in specific lung pathology. j -. 2a. Silicosis increases susceptibility to , tuberculosis. of disability, "with the' toxic* dusts, trouble may result from swallowing or more rarely from skin absorption, as well as from inhalation. Inhalation, how ever, is by far the most important means of absorption of industrial dusts. 4. Irritation and ulceration of skin and mucous membranes may be caused by such dusts as lime and chromium compounds. ` .......... Pneumoconiosis 5. Zenker applied the name "pneumonoconiosis" to the various changes in the lungs caused by the inhalation of dust. The term has now been shortened to "pneumoconiosis." It represents been carried on in the North* American continent more actively ixx-t;the. past decade than in any other period. The hysteria with regard to silicosis and other occupational diseases has now largely subsided, and the subject is be ing more carefully considered'and more soberly judged. - .. WMi-Hoi. F:~: The Problem ' : t-i' v . -*a 5rTT 7. Modem manufacturing methods are, in many instances, creating consid erable dust. Much of this dust is often released in the immediate area where men or women are working, and this fact compels a practical solution of the problem. . - ; mSust* . . - b. The systemic reaction caused by such toxic dusts as lead, radium, man ganese, cadmium and mercury com three words from the Greek, which mean '*. .*;' *~7 " _ 8. The first step in the prevention of injury to health by dust is the control of pounds, when either breathed or - swallowed or possibly absorbed through the skin. c. A transient disorder known as metal fume fever, from . the inhalation of finely divided metallic dust or fume particles such as zinc oxide. , - i'- . kt&si v&s its concentration so that workers will not be exposed to injurious amounts. In order to obtain wide spread control of dust throughout industry, it is necessary .that information be developed and dis seminated on the effect of various kinds d. A reaction, allergic In nature, caused by breathing organic dusts such as ; pollen, flour, certain pulverized woods. e. An increase in bronchitis and other acute respiratory infections by breath- 1 -wv > . ' -. Iistx*--c?* TJ and amounts of dust to which workers are exposed. ' :. Y-cij' -V . Origin and Properties , ing inert, non-fibrosis-prodncing dust . - such as coal, emery, limestone, marble. . ph7ii, *3. In each of'the above cases, the inhalation of dust can be'the sole cause Figure 1. Dust couaung by standard .ft-S light field methods. _2V.- 0. Dust is formed by reducing solid materials to small sizes. Processes like -` ! v `(C'opyrujht, 1929, 1939, National Safety Council, Inc. All rights reserved. Printed iss U.S. A. TX TINER RMCOO 2 2 7 61 uwacu uv ui cauuut ixuuJs ffitO ^gure '* x3t^^S,f!n^Sa^K?|^^Pse jnd~no^tL^Ymgl'tfi&n^rSch'the Ig'shed using'pneumatic,, banker. ''"Neither g^Ta?yfPr?>f^fgwwT^ofiSTTsOrijm 8&FalriSStteV%^^ ^fgoggle* and dust-control hood in use.'' ^ w,,, Ithy red tosrardjsyjnptbms cal?? Those prd3T "described^ as; producing'general* _,_ ,,toxie?."A(lust may be l grinding, crushing, bksting and_drilling 'white^c^ i^r^about -p__ro_diu__c_e djusjtl_p_a_rt.i?c_lie/s_ o_ ef s_izes` ?fr>o_1m_ tiht e' ;I1,pnncwwnawTtpnttEn WAmiail aim _______ 3%$gtffiMltrgic.~- microscopic to the visible, their composi- ,Jct SO microns in diameter.^. cHoweverJ ^ tion being the same as that of frh parent " th reflection of light from a shiny par- . materials if not altered chemiadly durT "** of quarts may ing the subdivision. Frequently the ^P&rticlevis as small as iO^iCTaDsjn .di-^_>fonn(j ^ |ow conccntratw&^find^ijso- *^r' percentage of some hard mineral such as ^'aineter. If is to be realized, therefore, r nated with non-living dus^t^ifi?>aSy'i~y4 quartz in the fine dust may be less than"*" that individual ^ dust particles^ small ~ 5-^T.~ Bacteria. ~ that in the parent material ' Commoh ' enough to reach' lung tissue Sre/.essen- --portint is the anthrax f*r. " t . My dusts denved from the disintegration of, 14 Ftimes may resultfrom any of^ Diphtheria, tuberculosis, ty^OT ^^ther Jf~ nek. and the organic dusts lie wheat liberal chemical or ' physicochemical* ^hadUus-produad diseas^^jP^ult^^; aannda fnloouurr., '..'. -^^^.^^^gA'anges'suc,h as zrnc- ox-idae, *form~edy-when_*-rigtferorimal-sexpiiotsiauered to infecte^MstsTT^Shedust a^3|gfie. W :<TO;` SfiiolU7rombi^ ^`' ^unua* zme vapors arise, from molten cause:> allergic ous fuels--coal, o--il," w'oo-d, etcC-c* on- * brass, or lead occurring in the exhaust tains droplets as well as dry_ particles. of a motor car burning gasoline containing teitra-ethyi lead.7 Tobacco, for instance, produces a wet hay.fever, eczema,' tmgrajn^neaqaches. gjy< l.etc-. kSr'-U ' Dus^ '!*. J2& , fnngi may cause annoyance jod aiscom- /g; i smoke composed of minute tarry drop 'Chennai " 1 feJ}- Mould on straw,^^isTy^ lets. The particle size of tobacco smoke -- table debns is typical of thjs_tygeoTdost ^3 is about 0.25 microns. ; 15. The chemical and'minendogical' ,/c^^rgaric Dhsts**^** make-up of the dust are'the deciding '' These a*re of mineral,'oijgin not re ' 11. When a solid is broken into fine factors in determining its', injurious quiring a living organism 7t5J produce ly. divided particles and released in the properties. It has been shown that sili them. ' Many dusts not classed *as^toxic air, one of the important changes that take place is that the space occupied by the broken material and also the sur face areas are increased many times con dioxide (free silica) in the form of quartz may produce a disabling fibrosis, whereas little, or no fibrosis, is produced by the equally hard and sharp cornered 'come under this classification.11^Classified under inorganic are toxic an<f/or irritant, fibrosis-produdng and 'nodfibrosis-pro- ducing dusts. ___ ~^J.\Toxie and/or IrhtanL^Qae. are 'f , from that of the original mass. For ex inherently toxic when inhaled, ingested" ample, if one cc. (.061 cu.ih.) of quartz or otherwise absorbed. '"Ajmoqjflfidn *are * is', crushed into particles one cubic micron in size, there will be lO13^ 1,000,000,000,000 or one "trillion) " particles with total surface areas of six' square. 06. . . the dusts from heavy metals and 'their if - compounds, such as'l.lrad^mercury, cation of . arsenic, cadmium, zinc." ~ **' '1 ' < r *.: ..-j- -- meters (9300 sq. in.) as compared with six square centimeters (.930 sq. in.) for the original block. If we assuml a dust Concentration of 100 million particles to each cubic foot of air, the one. cc. of material will occupy an air space of V'" i '' v;LA- * *rr I 10,000 cubic feet. O- .,12. With the exception of such fi- _ brous material as asbestos, the dust par ticles must be smaller than 10 "microns ' (one micron equals one" twenty-fifth i-f-Vv. ... 'r*: ife' ->** s' . < '17o'Jr***'*** * : ^ r:^\~ < Figure 3. Granite surfacer in operation, without and with dust control orondM. TX TINER YdiC 00 2 27 6 2 ?-\/ ''&&}&'% ->2yc-c- ` trbi/sTRiAL Wsr: ^ .v . - 'V-, '-iT'' _ ??* . ~3.>V. 2.r Ftbroiit - PradttcmtrfDkttri'pST^ rwrv ived' means^^o^dust valve --'^most important ofafthese ate-thft, ino^T*`b wcytes") which ingest' the dustpar- and carry them .td'ajystem offine ^a_ s'*called jbsnympliatitx ^Nbn-Fibfbi^rSi^fD^ff- \Urtf: c^ahd'fadr^'contents Tuf -These are inert, lariilfbyo.Ui&rraetves'-'sSfc .% ^ fiedj'tth roug.h t*h--e----s-- e caa.*nwals_'Stksorf .s.' e. aitanT reservoi; *. i v ~ > >* -': V ' corundum, emery, ' ^jpestooe, toignesiti marble, plaster pans, pbfijhof rouged etcr : - TheVRes* p3iratory System Op^dicroscopic 'djBt'j)artic_ riy ol wn^athncted'by gravi^but'fce^ Retention of Dust _ _ , (. .)V;, Up,--j." the smaller dust particles settle out more 17. In the human; repiratory; sys; slowly ~The settling motfimofa dust igure. <.% ,Ground silic* dotaped oato the; ipron of k conTeyor.'wWe-the etjT^'l , dosed conveyor exhaust hocxfiLnd the use - ^ in approved^rcspirator by' thi operator. " tem, there are complicated mois^pass- j&de through' still' air wffl vary With .......'.t.i.p..?...- ~ &liS ages, on the wails of which dust particles fibers are the .cause of the'physical irri- will stick. Also, the nose' contains hairs yftation resulting in asbestoSs?/^ which catch some dust However,`the respiratory system can become 'over loaded with dust, and when this hap pens, the dust catching mechanism functions poorly. 18. C. E. Brown has estimated the average amount of dust a normal man will retain. Breathing at the rate of 20 respirations a minute, for example,' he will inhale about 10 liters a minute and retain 60 per cent of the inspired dust. It is estimated roughly that the reten tion of common silica dust is about 50 per cent, but the way this dust may be divided between the upper and lower respiratory passages has not been clear ly defined. Drinker has observed in the case of metal fume fever that slow, deep breathing, possibly five or six breaths a minute, is much more likely to produce a fever than the normal rate of about they must be small'enough " "fij, ;The finer particles ^fjdust re ^float about in' the air or be carried main suspended in a still atmosphere for bjTair currents. It has been shown* by relatively long periods of time.. Their research' that dust particles musf be . chances of being inhaled are,- therefore, smaller than 3 microns in diameter to ' greatly increased. The smaller dust par cause silicosis.' However, since 'all at otides also travel farther awayrfrom their mospheric dusts include a majority of '' point of origin, and inasmuch'as'the particles smaller than this size, the par larger partides settle out very quickly, ticle size distribution of dust in the air the farther away from the dust source, is; of little significance. McCrae showed the greater will be the percentage of that 70.per cent of the partides in sili smaller partides. . Z-Zct; .Tr. - V V cotic lungs 'were found `to be less than one micron and that the largest partides did not exceed 10.5 microns in their greatest dimensions. Results since ob tained by other investigators have served to substantiate this comparative ly early statement. ' -,,..t .. . r24. Neither upper nor ,lower size lunits have been suggested for toxic sub stances, as lead, etc. It is jhe opinion of Drinker and Hatch that' no physio logical size limits exist fo'these sub stances. : '22. In silicotic lungs, dust partides ^>-*71- Silicosis in under 3 microns greatly outnumber those is. Undoubtedly the most important 15 breaths h minute. This is supposed of. larger dimensions. Some have be kind Of lung disease caused by the in ly due to the higher retention of dust re lieved that the human respiratory halation of dust is that which has been sulting from deep breathing. However, we cannot select by any known exami nation the men best suited to dust ex mechanism is responsible for this size grading. It must be realized, however, that considerable size grading is done in named "silicosis." Definition V * '' -'J-. posure, although some men show them the. air before the dust comes into con '26. Dr. Gardner's definition of sili selves obviously unfitted for dusty at tact with the respiratory organs. An cosis is as follows: "Silicosis is a chronic mospheres. - n . . i . , excess of small partides may be found disease of the lungs resulting from pro 19. The way in which dust particles are removed from the respiratory tract has been described by Dr. A. E. Barclay, British specialist on X-ray. The bronchi or respiratory passages, are covered with a number of tiny, hairlike cilia or mi croscopic whip lashes. These cilia make a fast stroke in one direction and a slower return stroke. They cover the passages leading to the lungs, and all keep in time with each other. This tends to push any foreign particles of dust up ward in the direction in which the bend, so that the particles may be ex pectorated. Dust particles which reach in the lungs simply because smaller partides remain suspended longer and in greater amounts. Particles above five microns will not remain floating in the air for any great length of time. The air cells of the lungs are large enough to admit partides possibly up to ZOO mi crons in length. However, according to Clark and Drinker, the most represen tative partide size in the lungs of men who have died of silicosis is one micron. ' pf2a.. Fine asbestos dust particles have been shown to produce only the inert reaction on the lungs characteris tics of other silicate dusts. It is, con: longed inhalation of fine particulate sil ica. It is manifested anatomically by formation of sharply defined fibrous nodules not over four to six`mm. in di ameter, which in most cases'are uniform ly distributed throughout alf portions ol both lungs; and dinically by a paucitv of. symptoms and physical signs tha usually appear only in the late stage of the disease and by a tendency to be come complicated by tuberculosis. In some cases, nodulation is concentrated in certain parts of the lunp, in which casts symptoms may be marked." .. >.*:. -- - . - wt '1x27. The International Siucosis Con to 2 -3 nx o O i-3 K> >-< N> Z ~o W cr> Z CO the inner recesses of the lungs are also. seauently, believed that the asbestos ference in 1930 defined silicosis u a 4--rBBALtff PtafcrTcE$?flLMPBLET ifo^'?' *35&Z i- - , - ... - i,,v Jtl' ^.Ji;'.v!ifA>SJr*-I . 'ri%K*.- ______,,.,,.i%_ 7` "pathologafl^ndiagn^cgvtngnuDgs due fefoUowing;<.thf,.secondjstage.evca,-if4the%xCdgsTin-theopfiuoa of thetSarana? ,- to the inhalatS^aM^cTlSIO, 1.H hJ>^d^ed,frW the^ dust* ^S^`ynmK^afe` d,evfinitions.;^**^ym^thtA-Tm^er~n>.o- n *^7^3com^es tisMeeve^refcanMd t&hyjpaiu&re?d rp^er^son (s77_, **"ait.:fMp.jivh?ar^t-vbSakgfHfip,S"c*^ Public Health ASqgauoaunqudes the ^frequently with fatal result!.'Jbe woric^*^Ie^wX?wy^3Snge ir^Y eH^mnnt'^al> etlirneil /itMaeiT /4na ^'tar f nnw faa kal/sat mami4I **( tt '.-- ------- * , ., ,4# .,.- , . , _ of panicles of free .silica less than 10 microns in diameter that it contains. : Cl '- I4 '* Factors of Influence ' ~y .,( 28. Silicosis becomes noticeable after widely differing periods of exposure to silica dust, apparently depending on: a The amount of dust inhaled. b. The percentage of free silica con tained therein. c. The size frequency, or fineness of the particles inhaled. ,i-'.~ a - ; ' (I. The nature and source of such other substances (including vapors and gases) as may be inhaled simultane ously or otherwise. c. The powers of resistance of the indi vidual concerned. f. The presence or absence of a compli cation by an infective process. g. The presence of complicating condi tions such as high temperatures or humidity, and unfavorable postures. Physiological Effects 29. In earlier years it was believed that the physiological action of quartz on the lungs was caused by the hardness of the material. In fact, it was claimed that men who worked on sandstone were harmed not only by the silica particles, but also by sharp bits of steel. These ideas were contradicted by Dr. L. U. Gardner, of Saranac Laboratory, who showed that silicon carbide and fused aluminum oxide, both of which are harder than quartz, had practically neg ative physiological effects when inhaled. Dr. Gardner also showed that dust from the diamond, the hardest substance known, was practically inert when in haled. ~ \ 30. Silicosis is considered in three separate stages by medical authorities: First Stage: The disease here pro duces no disability and does no apprecia ble harm. The affected man can carry on his operations as well as ever. Second Stage: Respiration is affected. The victim may be bothered by labored breathing. A,V Third Stage: This stage may develop ,*,rr4wv**v,*7*^%i7firlwa**.v;* xuc ^^w**-.* y Xjd ^ r complete'occupatibnal'anS medical his- "on thelunn'fs as followsrmiere quartz41 t0ry '<if the embldyee<rshoulcf be car' 'dust is inhaled and is passthrough thd* ~ - -. - -i-* - - -- -- - ' - - ~ figure 5. An automatic bag loader han dling finely powdered silica dust. An effective local exhaust system is in oper- ... . adoo. 32. From most industrial experience the development of silicosis may not be anticipated short of five years. A few cases have been claimed to develop in as short a period as one and one-half years, but these were under extreme and un usual conditions. There has been evi dence that alkaline materials, such as soap powder, accelerate the develop ment of silicosis, but this has not been substantiated in recent experience. 33. Silicosis is a disease of which tbe victim may be unaware in tbe early stages. Its development is usually slow and unperceived.. Inasmuch as silicosis cannot be cured by any means yet known and in its advanced stages is frequently complicated by tuberculosis or other infections, the importance of prevention is apparent. Also, in many industries, new developments have greatly increased the dust output. In granite stone cutting, for instance, and in rock drilling, dust production in creased tremendously with the introduction of pneumatic tools.' ` " )' V . r>- c' 34. Men wi^h early first stage sili- air takes place. "'At .this" point,, as the dust is a^ foreign matter, if. is~ ingested" by what are known as "scavenger" cells which carry it through the walls of the air, sacs to" the lymph drainage canals located outside the air sacs.' This re sults in a rapid increase 'of tissue cells which narrows the lymphatic channel, hampering elimination, asT it14is along these canals that foreign substances are removed. Also, when silica is'being re moved, the particle may kill the scaven ger cell by which it is being transported, with tbe result that all dust particles are not removed from the lung.' Instead, they may remain along tbe course of the drainage canal. Apparently, these small particles of silica dust are' toxic in this location and the tissue cells in the im mediate vicinity are altered 'and re placed by what is known as scar or fibrous tissue. The ultimate result is larger areas of tissue or lung volumes in which capillary action is definitely re duced -- through which a normal ex change of gases between the blood and inhaled air cannot take place. ^ 36. As the inhalation of silica con tinues, the amount of fibrous tissue will, of course, increase, with the ultimate re sult that the lungs will not readily oxy genate sufficient blood for the body need. This produces a shortness of breath in the affected individual in pro portion to the amount of scar tissue in his lungs. a ' j ~-~ ` tz i '- s . Free Silica vs. Silicates . / -i - .` * " ~ " ' ' '/<- 37, With the exception of asbestosis, the silicate dusts have not been shown to cause a disabling lung condition such as is produced by free silica. Experi- ""^cted both by.causing ani- t0 mhale dust over ,a lon* f*nod of time and by injecting dust in their peritoneal tissues have shown that sili- TX TIM E R RMC00 2 2 7 64 ave not been juw- limited Js^sfated 'that lalile^indicate that, e^'aj^sabtag,J1u--ng /Ccondition -is `MTesult~from,expqsures to silijts^(oih(M;~2iin"asbestos), there liner an unsuspected presence of free "^in'the: dust, the. victim has had vious undisclosed exposure to free I'dust, or there has been inadequate pretation of ' the x-ray. On the ^fher hand, Dreeson et al. have reported - pneumoconiosis in workers exposed to ^liigh concentrations (150 million par- per cubic- foot of air) of clean tabedjmica^' Greenburg and his coJiSxs jound' fibrosis "associated with rympfoms as`dyspnea'and chronic ofi 21_tremolite talc ^ders^and millers. These men were KffJ'emgioyecS of 10 or more years ex- fRMure and the reported dust concentra- r.dons _are as high as 1300 million par* t'ticjes ''per cubic, foot of air. In two ^jinnes in this area, Gardner had found i quartz ranging from 12 to Z0 per cent, but in the mills, where all rock is mixed ; and crushed, the dust showed low quartz i percentages both in Gardner's studies ' mid those of Greenburg. This subject oT Jhe possible action of silicate dust on_the lung tissue is being further in"vestigated, and any indications that ; certain, silicate dusts may be causing a (.disabling lung condition should be givesMthorough study before conclusions are Cached. .1... F .. " 'J * -Mixed Dusts , ,>,37a. Where free silica is mixed with "other dust, the greater the percentage ,of-free silica, the less the dust exposure ; required to cause silicosis. Since some (dusts such as gypsum'have an inhibit* ; mg .effect, there is an increasing tend ency, to evaluate ' the extent of the hazard presented by mixed dust on the -basis of the individual dust exposure. :More data are constantly being ac,Cumulated on the actual effects of vari ous types of mixed dusts. . ^ it ' *' I i 1: ^ \ ;V i 'V 1 1 "" nr ^ Figure 6. A rambling' barrel used fof finishing small castings. The barrel u-in oper'Srratioo, but note the absence of dust due to a good exhaust system. Asbestosis -`C^fts^txws 1. <r3 ;** 38. Asbestos is the only silicate at present recognized as causing pathology, and even its reaction is definitely differ ent from that due to silica alone (Drink er). Its behavior is the exception to the rule that silicates are inert, at least in uninfected tissues. Asbestos, when in haled, produces fibrous tissues in the lungs of both men and animals. As bestos is made up of hydrated silicates of magnesium with variable amounts of iron, calcium, sodium, potassium, and aluminum replacing portions of the mag nesium. The property common to all of this group is the fibrous structure. It has been shown that the presence of fibers of asbestos are necessary for the production of asbestosis and this fact, coupled with the observation that fine asbestos dust is analogous in its inert reaction on the lungs to that of other silicate dusts leads to the conclusion that asbestosis is the result of physical irritation of the lung tissue and not of chemical action as in the case of sili cosis. ' ' ' 39. Following a study by The United States Public Health Service of the asbestos textile industry, it has been recommended that the dust concentra tion be kept at less than 5 million par ticles per cubic foot of air if asbestosis (s to be avoided. The use of a.standard based on the number of fine particles result from the use of dust determina tion technique developed for the study of silica dust exposures. Although fu ture research will undoubtedly set up a standard based on the number of as bestos fibers in air, keeping the fine dust at less than the suggested standard will keep the concentration of injurious fibers within safe limits. - Infection . 40. In the opinion of most investi gators, the factor of infection is most important It has been observed in guinea pigs with chronic pneumonia that in an infected area which developed before exposure to dust, "the local branches of the lymphatic system were not so efficient as those in the rest of the lung. Silica inhaled into tissue thus damaged appeared to accumulate in un usual amounts. " .i-O'Cii.- ` 1 '41. Since men with silicosis are more susceptible to tuberculosis than are normal men, there is often an excessive incidence of tuberculosis among such workers. Usually disability and death of a silicotic, when due to pulmonary conditions, results from the'complicat ing tuberculosis. For this reason, it is especially important to have a re-em- ' ests-r vi?' i'''-' -V-:- -- 6--H.P.P.-4 ... . ....-HEALTH PRACTICES'PAMPHLET NO. ; ployment.and.pOT<ai(3X:>ay."program^'riedi from lP'toj^percent depending . nwnia,1 bronchitis : among 'wo'rkervigg36e@osilica dust.""on length orexposarvanS^dtut con'cen- ~kilmenK. * -. 'ttchhuee4l2ppr.erfiSsse1antkt--di'm4&e*_tfh_cte_f_cft_ef'_'ias_S_tum_BbefeTlnSlot^^wrffi^l:a^"^A^ti? ^ra^0] .1 TS } i*"t'ag* eTo/^yi*n?' & _-_S___f__t_.eA__l_s`_So_,-_a___3______)_1_ ytoea_r_sthaatgJoo."r^Tohred.inpwr"ojrpjoonss.ua'rme` pftaior nfro-Srm,,O.^< hopeless.. 'Silicosi?ll,* :gratB3ally* being? tions greater than 300 million, particles per cubic foot iofafr.; lie'^ Aocor^ngjK^K^^RuMell.^the T, ~xpiSi. "r v> , S*<rt+*-."xv*: in_`v.mTegsi`tl'iilgnia*,ttho.tres'^sh* am- vVepnl,oa.tnic't,e?'datt^hia brought under control^[flhiee.t^imtpee^ is'.nnoott di^ilfty rate'mn<mg%troate miners J'ahd in.Ifie .same workjilat far distant wlien dangerous*concentra- ^from ^fespiratorjr^tubertmlosa'is' about dffno^develop silicosis to tions of silica dust"wiH no longer be per-'^**^ ~"*~*****>4*feSe>s.<C^*E: gree.'.'^Ii is possible for? mitted In American industries.. Periodic be an eariyrvictim, while i examinations of those already employed "? 'ing beside him remains ___r____ will detect new infections in', persons freeJjThis angle of thfjproblemmti now silicotic. Prompt ^institution of5^' cates' a*heed for further research?' treatment will eliminate'* most of the hopeless cases of silico-tuberculosis. Preemployment examinations will insure ^ placement of men in positions that they can fill without damage to their health." s50. It is well, nevertheless? hFcorW sider all coal mining as involving a risltj? to some degree, depending upon the type of rock being drilled. While the hazard' may not be as severe as in most metal Coal Mining ; -V", 43. Anthraco-silicosis is a term used for a form of pneumoconiosis commonly called "miners' asthma."' According to Public Health Bulletin No. 221, "Anthraco-Silicosis Among Hard Coal Min ers," it is a chronic disease due to breathing air containing dust generated in the various processes involved in mining and preparing anthracite coal. It is characterized anatomically by gen eralized fibrotic changes throughout both lungs and with the presence of ex cessive amounts of carbonaceous and siliceous materials. 44. Symptoms found in early stages are shortness of breath, cough, pain in the chest, and possibly physical weak ness. In the advanced stages of the disease there is loss of weight and de creased capacity for work, due partly to pulmonary infection. i - k' 45. In studies conducted by the United States Public Health Service in Pennsylvania, no cases of anthracosilicosis were found in the controlled group of hard coal mining employees whose dust exposure averaged less than five million particles per cubic foot of air. However, the prevalence of an thraco-silicosis among the entire group of employees was found to be about 23 per cent. Among all except rock work ers, less than two per cent of the men were affected when the duration of em ployment was less than 15 years, regard less of the amount of dust in the air. Among rock workers, who were exposed to dust averaging 35 per cent free silica the prevalence of anthraco-silicosis va- f':-. Figure 7. A method of receiving dun into trucks and auxiliary collecting equip- - ">ent. ' '-* * ~ ~ * V * n *_ '.'a.'-jT *yi times the rate for general manufac turing. The pneumonia rate is less than one-third of general manufacturing. Bronchitis, however, is a rather common complaint. . 47. S. L. Cummins and S. F. Sladden conducted an examination of a large number of coal miners' lungs in South Wales. As a result, they made the statement--"Coal is retained in large amounts only when there is a really high silica content" They added, "We be lieve that in the absence of the silica factor, there would be, under modem mining conditions, no serious degree of anthracosis." E. L. Collins and J. C. Gilchrist have claimed that workers who have had considerable exposure in trim ming coal ships where there is practi cally no silica exposure, but nevertheless a very heavy dust condition, showed some fibrosis which, however, was not considered disabling. : 48. A study of 2500 post-mortem examinations made in Pittsburgh hos pitals shows that city air which may contain an unusually large amount of coal dust may cause lungs to become darkly pigmented but yet produce no pathology of importance other than per haps a predisposition to colds, pneu- mining_dperations, it is of importance at least because of the number of work men concerned. - s * -i' - ' ..A- -i v*' 'i.'rr. i 51. The hazard of silicosis seems to be practically absent in the manufacture' of cement. A recently completed survey of 2000 cement plant employees in all sections of the country by Dr. LeRoy U. Gardner and staff of the Saranac Laboratory for the Study of TSiberculo- sis, has failed to demonstrate^that the inhalation of cement plant or" quarry dust has a significant effect on the res piratory tract Neither did it appear that men who had spent their industrial lives in such atmospheres were unusu ally susceptible to respiratory infection. The incidence of influenza, disabling colds and pneumonia was not high. No cases of clinical tuberculosis were dis covered, and the incidence of healed or latent fod as revealed in the roentgeno grams is the same as that found in the general adult population; namely, 4.5 to 5 per cent. Dr. Gardner has stated: "Although the medical examinations re veal no evidence of respiratory injury from cement plant dust, even after pe riods of long exposure, maximum con centrations in dusty areas should be re duced to 100 million particles per' cubic foot (light field count, impinger tech nique) as rapidly as economically feasi ble. High concentrations may not be dangerous, but they are not compatible with good housekeeping standards. "An exception to the general rule is indicated by the discovery of two cases of . non-clinical dust reaction in this group of 2,000 persons. .Those men had been exposed to quartz dust (usu ally in the form of sandstone) used in the manufacture of'special cement. While possible inhibitory 'effects of TX TINER RMC0022766 . ... ^JtS^irauSf^wsomng^Tjyyprpviding bath* dttiCoveralls. jnoutlT^J - |,, | ,,. Jmtea^f . prevmtin^^ fottctrve- ^^^e^apeiaulead Tn^rpL^ airithe men *3 Sectfre- as the^w^^jblig^c^^brSS^ef^JJnfortuiiately' " %*h* ,dt?1^-^tbg5ia&ligmecm(a '6egn&)ne under a .nuiiu oKtoIeration have 7V7'*&* nei ?Tfiere?ore,' the limit' ^ph^SlC^lM^^mUSt nWT ^ articfesTeSilhim lO.micronj forgotten,that(the great .majority, of m-_ jg ___ref'fftfh4*B?eatMmff'ione was' "difitrial poisonaenter tfinbbdy wfththe_ ijlfeHIyyse^itiJve^iSfUdn particles; ,, in^irS aS^iS?'thaf^whiie a workman**^- rjuljiftced.fJoSo&t .toefs; sPuur.baslicdeHteeramlthineSderbey- breatheTl^^^r^T^^g^^w^a rdaVSntkht ffeM'coun't.''" : trr-1l<tgnesjaj1rUaUjjUnItCeUdIuUnUnIKgtUhieceCilgkUhlVf oUl r*r2S toxic Du*sct.s<*KJkT.\1,\ , 3rething vs. Swallowing cv_ " dence.tiSt^ioreir'far more dange^of* bemg'^iionSrhy inhaling toxic dusts Conditions arislng^frbm allergic eraUy, workers may be poi- than Sy eatmg^hisn with' food or taking ~ disturbances 'of an occupational^ origin necf by ti oxic "dusts much more quickly them invliquids.~ But`all "precautions '"are coming more into'prominence, from ugh inhaling them than by swallow* ; j:.' -- *u---------.------*:-- --- ` ^ ' iSomemay be picked up in the blood cir- ^ [^certain substances with which they come 'dilation and then moved on to the liver. -0. The practical problem in con- " in contact.' These substaricef'may in- fThe liver, however, is an effective filter nection with lead poisoning is the pre- * elude foods, drugs, and vapors and dusts land detoxifier, and it is only the poison , vention of. serious lead exposure. The of.'various kinds. A; wide variety of [.thaTgets beyond this point that enters problem consists of two phases: one, the substances may, therefore, be responsi- general circulation. On the other hand, determination of the limits of safe ex-" ble for allergic reactions in various in'dusts'that reach the lungs can pass di posure, (see paragraph 68) and, two, the dividuals, which substances may have no rectly into the blood stream, to the reduction of'lead exposure below these 'effect on'others or, in some cases, may heart and then to~all parts of the body. limits. w.^s'^ewn be of positive benefit The types , 'l-S3. Alice Hamilton, in "Industrial i6T ' We'ust reSptiw thlt ff'f0"3 ?****affected in Toxicology" (Macmillan Company) lead is a normal constituent of a living d,v,duals * substances may. also points out the distinction between the two ways in which poisonous dust can be taken into the body in the following paragraph--"A great deal of money has been wasted by well-meaning em ployers who sought to protect lead fur- animal and that there is a level of lead absorption which is safe. Lead intoxi cation and lead absorption can be pre vented by engineering methods. (See Health Practices Pamphlet No. 3 and Safety Instruction Card No. 116 on this subject.) gready hoth m "tuns."d m degree. A single substance may, in one case, cause intestinal disturbances, in another case develop asthmatic attacks, and in a third case cause a skin eruption. Still another person may be affected in all three ways. . - --i y.* Figure 8. View in an iron foundry showt' ing bench grinders with exhaust hoods. Metal-Fume Fever " - '' 57. Metal-fume fever may be one of the results of breathing dust from metal sources. This malady usually follows contact with a heavy concentration of magnesium oxide, copper oxide, lead, zinc oxide, and possibly lead oxide and manganese dioxide. 58. The symptoms are chills fol lowed by a malaria-like fever which usu ally passes off within 24 hours, allowing the. worker to return to his job on the following day. The first attack usually immunizes the victim so that attacks are not experienced consecutively. How ever,' after a layoff or an absence from contact with the dust, a further attack sts likely. Slow, deep breathing, accord^ ing to" Drinker and Hatch, seems to ; bring about the symptoms more quickly. - 61. Dusts of various kinds sometimes cause attacks of asthma. Asthma may be suffered by stablemen from exposure to horse dander and by furriers from exposure to fur dust. Other persons cannot work near animals or, in fact, keep pets or sleep on feather pQlows without suffering acute attacks. Hay fever is another type of reaction to dust on the part of certain individuals. These dusts are frequently in. the nature cl pollen, as from plants. Hay fever, it claimed, however, may also be caused b other types of dust. In any event, th precise manner in which an allergic in dividual may react to. a substance t which he has become sensitized canno be predicted. ' 62. Many believe that allergic in dividuals are horn with' their particulai rMC 002276 sessSSSb** ^*^#MLTHPgApTIC: MfBLET NO told .that Xdegrees of air'd. 5'best'kSbwn *praL^. ^uclTstandiuds'VSulclEidi, walue for. a single industry. >ft' ..*,.7, v is,, ' fent conditions and in- or /there would be a'question ^65.As^the,result of. {practical experience in dust. ____ ; the South African gold mines^Peoncen 'tration ofJ one mg: of "dusfc*pcrrcuHicj .meter of air"was accepted M^slamSEcT1' and is now known commonly^as "the"1* South African^standard." lJp&1934,~l2? G. Irvine stated that no miner.Vhb haJ ~ entered the industry since this low con- J centration had been maintained'had, as ~ Figure 10. Portable industrial vacuum cleaner. types of hyper-sensitivity. While this is probably so, according to Dr. May R. Mayers, individuals do not become sen sitive to substances which later cause the trouble until they have had sufficient contact to become sensitized. When a person who is hyper-sensitive first comes in contact with the substance, he is not aware of his condition. An "incubation period" is required, during which time repeated contacts perhaps sensitize him to a point where subsequent contacts may result in immediate allergic reac tion. This waiting period may vary from a week or two to several months or even years. However, the allergic tendency must have been in the indi vidual to begin with, and then there must be continuous or intermittent con tacts with the substance in question in order that the latent allergic tendency can be brought out. sjw-iijcj-j;.''-; 63. It has been claimed that once a person has become sensitized to a given substance, he may, more readily than before, become sensitive to other sub stances. Occasionally, too, it has been suggested certain individuals are capable of developing a certain degree of im munity as time goes on. However, from the viewpoint of prevention, it seems logical that workingmen who have be come allergic to certain substances in the course of their occupations should be encouraged to go into other lines of work, for in most cases the tendency is to become more sensitive as exposure continues. -*" Permissible Dustiness 64. Generally, we lack data for de fining rigidly permissible dustiness. The point has not been reached where a man ufacturer can be told the exact concen trations at which, for instance, his men will start developing cases of silicosis, asbestosis, or lead poisoning. He can only ^66. If-was* stated by D. E.v Cum mings In' a paper presented at the Second Symposium on Silicosis at Sar anac Lake-- "'* v J . ". . . Information from field studies made in many parts of the' world indi cated that a normal man might work 'in pure crystalline silica dust for many years without impairing hishealth if . the concentration did not exceed five million particles per cubic foot = !o*f*a:. ir.'" - 67. Dr. L. U. Gardner states, con cerning the permissible dustiness where silica is present: . . ,;. 1 "The evidence now available makes ... it seem improbable that a silica hazard ,,is defined solely by the number and size of the silica particles in industrial . atmospheres. The other components of a dust modify its action. Some may inhibit, others retard, and perhaps some will be found to prevent its in jurious effect. Because these possibil ities are recognized, it becomes diffi cult to set up definite standards of per missible dustiness in industrial atmos- 'r . Dr. Gardner continues further: ** i . "Not enough is known abont the ac tion of protector substances' to warrant the recommendation that they be em ployed to prevent silicosis in industry. Our aim should be to reduce existing dust concentrations rather than to in crease them by adding more doit. T would very strongly oppose the recom mendation that protector dust be nsed to attempt to prevent silicosis at the present time. But t do believe that we should attempt to discover'more about their action. Some, like gypsum, seem to combine with silica in the atmos phere, forming clumps whtchare too heavy to remain suspended in air and too large to pass the barriers of the nose and upper respiratory tracts. With such information at hand, it may he TX TINER RMC00227 68 qN'ojSfManganese`50-zng^ericubic meter 'jv^ls'safe (Drinker & HatchjC. -^ayJjControl'orDustiness >??& .cjftwv j>#70.j5.Tliere are various ways in which "<!ust diseases and "annova&es .'may bi t'-avdided*:,^S^^^^ai^ii H5> ^000,000 particles pgrcjibyc foot for coal dust containing" nof<OTer*,596 quartz, tO.OOO.OOO to 15,000,000 particles for dust ` with 13% quartz, and."51000,000 to. 10,- . t-^^the firsthand most important defense ' against " industrial^" 'disease. 'Jobs ' '' should be performed in'clean air as ' % ILead-^ILegge and Duckering) more i'than .5'mg. per cubic meter is hazar dous and (A. E." Russell et aL), less : than .15 mg. per'cubic'nieter is safe. Zinc oxide--(P. Drinker, et aL) 14 mgs. of zinc oxide per cubic meter for 8 hours of exposure or 45 mgs. for short exposures'. ; >>. 69. Of the metals, the following suggestions have been made: The American Public Health Associa tion Committee on Lead Poisoning state in their comprehensive 1943 Report that "when the air of workrooms regularly " contains more than 1.5 milligrams of lead per 10 cubic meters of air, cases of dis abling lead intoxication do not occur among men who work regularly in such workrooms, and cases of questionable or minor intoxication are rare. In practice the attempt is made to maintain the lead content of the air within such limits as will yield an average of not more than 1.5 milligrams of lead per 10 cubic meters throughout the working day, while pre venting the occurrence of materially higher concentrations (5 milligrams per 10 cubic meters or more)." Zinc Oxide: To avoid metal fume fever the concentration should be kept below 14 mg. per cubic meter for 8 hours' exposure or 48 mg. for short ex posures (P. Drinker et al.). - a certain degree. ... polishing wheelsA'`Y,4*tiT9P-" Exposure can be. limited by -ft.' redue- `4.3V&*' k&s!; s'? ing working hours' where dust con- '7? 'ifP-a. uJ. .',.J centrations cannot be sufficiently re- '* 8.1 A final method of protection is .the . . 'duced to constitute an otherwise -wearing of special protective equip- . safe condition. . '..'.`r . ,. " ' . ment by workers. This step is fre 3. Safe processes may sometimes be ' . ' , substituted for those of an unsafe nature. An example of this is the ' ' substitution of - abrasive wheels made from synthetic abrasives con... taming no quartz, for wheels made from natural sandstone, which is quently the last resort and is used ~~*unly in an emergency' or for jobs of short duration, but-, it is never theless of considerable importance. (See American Standard. Safety Code for the Protection bf Heads, Eyes and Respiratory Organs.) >sK\' . " about 95 per cent quartz. . 71. In many localities axles or or 4. The substitution of ` wet methods dinances for the control of lustiness are . for original dry methods has exJerted considerable control over ^.'.'I' dusty atmospheres. Dry drilling is : the cause of considerable dustiness in mining, which may be greatly re- in effect which should'bet investigated and followed by employers' seeking to improve working conditions.'-' 'v.-s t>.i -" .L''9isk ' duced by wet drilling. This is also true in many construction and Local Exhaust Systems >;,/?stfv .. J quarry jobs. 72. Local exhaust ventilation for the 5. An effective method for preventing the escape of undesirable dust into the working atmosphere is the local exhaust hood. It should be placed close to the source of pollution to :. be most effective. The air should be discharged'through a dust col lector to prevent contamination of neighboring areas or return- of the dust through open windows into the plant. control of industrial dusts 'and fumes consists of four principal parts: - - ra. Jl a. Exhaust hoods tyt*; b. Piping or ducts . V. c. Air cleaning plant ,HlS V; d. Source of suction srfr - 73. While each of these parts should be designed and installed to perfomTiti 6. The routine recording of dusty con- required function with respect to the ; . centrations is a valuable check on system as a whole, the exhaust hood the existing exposure. Periodical probably demands the most Jareful de - counts of air samples are a great sign, inasmuch as the degreeTof control v; - , help in showing whether or not there is need for further control. . . secured depends to a largeriextent upon the shape and location of tlifcljood--and 7., In some cases, fhe application of the rate of air flow to it--(fiXnupon any ' general rather than local exhaust ventilation is desirable. There are other single factor.' T< ; instances where the source of pol . 74, Hoods have toVronS3erable ex luting materials is constantly chang- : . ing position and local exhaust bec comes difficult and impracticable. tent followed the design^ao^employed in such industries as'woodworking and - 1 Here a general ventilating system metal grinding. HowevSjafnoted by ` " _ may be the only answer. .Theodore Hatch, in rSm^^Es the in- 1 i- ^ - --A-' . .. dust problem ned by- * Courtesy, Kirk end Blum '1 . ' ` - .<' .Manufacturing Company *Th tight metboda of prtrentlon given here gjenic AZld economic ASj ngatireiy be- ` -v-w- , . Figure 11. Exhaust system for removal of lead dust and fumes. &rt listed In thU order In "Induatrlal Medldne`* by Clerk end Drinker, published by the NtdonaJ Medicel Book Compeny, Inc.. New . ^ork, N. T. ^ 4+o'p*9\.` yODd the limitatlons^O, t_indus tries in which the prod"uc' ti`on^ dust has been , -. t. A - * . TX TINER RMC00227 69 io--H.P.P.-4 PRACTICES PAMPHLET NO. Aj: /- - ' SW <*' .. " -.- -ft a Jnuisance rather SuaiWth of .-dust production .most DC: under, ab hazard.'^ Occupation 'diseases: haVe solute control."'' come to .mean s^much^uj^Ihaustry^In s,..;., mbdical costs and compensation as'jwell *77 '... Proper'design andf location of the a. s`"`tiht e ,he-ai.lt.h-' 6 `--i.tchat-'-t. here'W>s'. suction opening and the rate of air'flow ample'justiflcation'/or'Stensive rS' *earch'^"into it is a matter of'utmostSipoVtancer and investigation" i^^5.dwhiopment'of Laws governing the flow of .aiz'into ex- the best possible design in control equip Must openings have been given in "In- ment. ' '"7 ' i <d4nnscttrrtiaa1l TDluuesftes*"' Kbyi) DTirninnlkraepr aann/fTHHaattrcVhi :** 75. To maintain's safe concentration - D?;Enclose the process incompletely of dust in the vicinity of dust generating equipment it is necessary to introduce to guide the air . flow "'where it sufficient clean air from, the outside to dilute the dust-filled atmosphere to the degree necessary for safety. In the util ization of general ventilation systems, care must be taken to' avoid excessive exposure of workers as'dust is removed from its source. Especially where local dust systems are being supplemented by general ventilation, it should be seen that eddy currents are not set up to in terfere with proper functioning of the local exhaust. rV*i**.. <T* --* 76. Undoubtedly, the best method of ventilation is the control of contami nated air at its source. To do this, there must be sufficient movement of. air toward the exhaust opening to counter act any tendency of the dust-laden air to escape into the surrounding atmos . 2> An exhaust hood which does not >>>enclose the process should be. placed ^L.with its opening as close as' possible f- /-r to the point of dust generation since r- \ the air velocity in the zone of hood -- 'influence decreases approximately ."..with the square 'of .the .distance - .from the face of the hood.'' . . *- ;> f-- ' 3. Shape the hood to conform with ' the shape of the area of dust pro duction so as to secure reasonably uniform air velocity over this area. . For a given required air velocity at the point of dust generation, the - velocity at the hood opening should be as low as possible. This is con- . - trary to the common idea that the . hood suction should be high.rv*.'**-'*' - -,..4. Provide flanges wherever possible * '" to reduce the air flow from inef fective areas where no dust is pro- 7 ' duced. -. phere. Proper hood design will make 5. Locate the hood opening, or part this possible with the least possible flow of exhaust air. The object of an ex haust system is to trap the contaminated air and not to remove the harmful dusts from it. It is suggested that the scat . of it, so as to receive directly any dust that is thrown off along a welldefined path, thus utilizing the di rectional energy of the material ' for its own capture. tering of large particles may be pre vented by the erection of suitable bar riers or, of course, by causing them to flow into the collecting duct. For effi cient operation of dust collecting equip ment, all air motion around the source r*~ % '"Design of Exhaust Hoods for Dust-Control Systems" by Theo dore Hatch, Harvard Graduate School of Engineering and School of Public Health, Boston, Mass. The Journal of Industrial Hygiene and Toxicology, November, 1936. -Fr^e'-uJl^p-ing^wT#^^- riirtri roiled sawdust to allay dust, - Wet >78. On the matter of^drilling, Har rington says: j':, **- "Dry drilling is, of cotirse, very much more of a dust producer than we.t drill ing--possibly in the ratio of 10 to 1. Wet drilling produces some dust, but if reasonable precautions are .taken with wet drilling, and suitable precautions are also taken as to ventilation, as to . the wetting of the muck pile, as to the time in which blasting Is done, as to the precautions which are taken after : going back to the face after blasting .. . . there need be no particular harm to .workers in those places, as far as dust diseases are concerned." . - 79. Prof. Philip Drinker, in com menting on the adoption of the New York State Code governing dustiness in rock drilling, stated: "This code divides all rock formation into two classes, class 1 being those with less than 10 per cent free silica, by weight, and class 2 being those with more than 10 per cent free silica. If drilling is done in class 1 rock, dust counts must be below 100 million per cubic foot, and below 10 million par ticles if the rock falls in class 2. - : -t.. es - Dust from rock drilling operations, uncontrolled and controlled by dust trap TX TINER RMC0022770 remove ; possible. ' ^1 fOl W3rd V W m . |s4 yjg y y | ^^ y - [fYt f f7 -- .-- ^ . - ,- , ^ |J|-- ^-^--,JT . ^ ^adoption of meahs to^llect the dust^'c^ftfeeS^insa/TA^^atiw^W at certain points ofproduction instead _/> - .-- -Or. Carey P.,,McCord, ChryslerCorpo- of relying upon the gen'eral ventilition^^^y^e?^TM*?;** the,E^t%ve^,Taitin Dr *v*` Vi&rTTiSSSPsJt,' current to dilute and transport the in Committee ofthe National Safety Coun- ,, jurious material Small units are now-~~'cilr tn'.wfitmgthis pamphlet, the au-,,_ Ptibiic^EeaLth Service; Jfr.Jf.JQ^elby, being installed in some mines at load-'* thors*have revised carefully the literal General Motors Corporation; TR. C."',*f ; ing Stations and orepass tipplers, theT ^ y-'gjT the*&d, a^d'nateful Stratton, Trav'eUrs lnshraruxCmpanyj'*?- ; installation and maintenance costs oC ' rtr~s IFri' r?y..* *' which are low and a. high efficiency is1; acknowledgment!* made to the numer- and Dr. C.E.A.'Winflow.yue Um- TX TINER RMCOO 2 27 71