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* V H\i!.X '? Vi - 5T~ ,.V? V- _ 'J\t r.clptfZ' * y* ^V-v-' >7 ,* ^ RMC- 1 65 Health Practices Pamphlet'No. j's.......... " ' * ` .. - %$*' , . ............._ sStowvI^^Publislied by l5^o^^Safety^Sunal7 Inc O 3 'r . 'i. -` - - ' ''V 7=: '; - '" 20 NorthWacker Drive, Chicago 6: ^ ' fe?: ::. ' ~f -M-s. ,^tsrlj;syr . ~ " 1 Ind u-strial Diist*>-~ --T'r.';". ' 1. The literature non 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 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. r.rrtr. Physiological Effects of Dust 2. The inhalation of dust may pro duce different types of reactions in hu man beings: a. Pneumoconioses (silicosis and asbestosis) which result in specific lung pathology. 2a. Silicosis increases susceptibility to . tuberculosis. i.; b. The systemic reaction caused by such toxic dusts as lead, radium, man ganese, cadmium, and mercury com 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. - "hmg,"'i`dmV7"(^'`abnomid - This pamphlet is one of more than ISO Safe Practices and Health Practices Pamphlets. It is a 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; state laws, rules and regula tions ; and municipal ordinances. Addi tional copits of this pamphlet art avail able. Member price, 35 cents each. Quan tity and non-member prices on request. *. tion,''"_Jhe present generaSy_acapted ' meaning of the word involves the con cept merely of "dusted lungi'fThe hind of dust inhaled determines "the' type ` of injury noted in the lungst^However, there is'one pathological process which underlies lung disease caus'ed by dust. This consists of a fibrosis'or a' replace ment of the elastic tissue'of the lungs by an impervious scar tissue.^."' 1. ; :v. . .: i j-.n vit. sr^'ai xiunp* .. 6.- Research on pneumoconioses has of disability. vVIth 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. ; - U\" ......... '' - - - Pneumoconiosis been carried on in the North.'American continent more actively in-V.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. f ' *1 .. - .. f .ns i- iq?. tfo vi. T The Problem - y.t- - - -. 5rT' 7. Modern manufacturing methods are, in many instances, creating consid 5. Zenker applied the name "pneu- erable dust. Much of this dust is often monoconiosis" to the various changes in released in the immediate area where the lungs caused by the inhalation of men or women are working, and this dust The term has now been shortened fact compels a practical solution of the to "pneumoconiosis." It represents problem. -i .Krais' .. / three words from the Greek, which mean - 8. The first step in the prevention of injury to health by dust. is. the control of. 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- ing inert, non-fibrosis-producing dust v ~-such, as coal, emery, limestone, marble. % .-'* <, V *3. In each of'the above cases, the inhalation of 'dust can be the sole cause ' ___ _ _ Figure 1. Dust counting by standard ; ji.3 light field methods. and amounts of dust to which workers are exposed. .: .-:-'`vrcij*-'- -v' Origin and Properries a 93 Dust is formed by reducing solid materials to small sizes. Processes like T. ffCopyright] 1929, 1939, National Safety Council, Inc. All rights reserved. Printed in U. S. A. .e. TX TINER RMC00 22761 see an ob- **s*i.* microscopic to the visible, their composi- J*ct SO microns in diameter.^. TSowever, tion being the same as that of th parent * reflection of light from a shiny parmaterials if not altered chemically dur; tide of quartz may be seen when the B,' Living,Organic Oust ,g-,These dusts contain partic __ __ , ol reproduction or''inriti$ieation,:^.nicb v . ing the subdivision. ' Frequently the ^partide ,, percentage of some hard mineral such as ameter. _. : V quartz in the fine dust may be less than"* &at individual dust fwurtides^ small; 'Bacteria. 'One' o^ " " that in the parent material " rnmmnb^enough to reach' lung ti^e.are.essen- ^ -portant is the anthrax ba< ' A>. .W <M<< .<,* ;f r. .- --j.i. ..-.i------- tT , , found in the dusts from - derived from the disintegration of It from any of. Diphthena,tubercdos.s,ty^^^dother^r.^ .p..hys.i.c.o-c- h,e-m,ic-al *^-vt-T^-----beb{afrarocccmmiillluusseJ--xpppUrrooosdduuurrceeedttoo diinnisfeefacestseeecdssTJ*t.t,5^*ayfSre^w&iltc-"^- oxide, formed when,, , terial-sensitized dust cat VAb: * ohs fuels--coal ofl/wiod, tains droplets as. well as dry bumip8 TMc vapors arise from molten ^ cause of allergic' diWSS? -mha*> <*'.le*d occumng> %. exhaust *t' hay fever, eczema,' migraind*fieadiehes. etc. ' Tobacco, for instance, produces smoke composed of minute tarry lets. The partide size of tobacco smoke is about 0.25 microns. 11. When a solid is broken into fine ly. divided partides and released in the 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 from that of the original mass. For ex >.5 . ample, if one cc (.061 cu. in.) of quartz - is crushed into partides one cubic Vt'V;i/micron in size, there will be 10*^(1,000,- 000,000,000 or oonnee'trillion) "partides with total surface areas of'six square 15. The chemical and mineralogical make-up of the dust are'the deriding '4 < .C, *-~Jnorgan-ic Dusts. -- __ . _ '-'V These are of minerarongin not re factors in determining its' injurious properties. It has been shown that sili con dioxide (free silica) in the form of quartz may produce a disabling fibrosis, quiring a living organism 7t5^produce them. 'Many dust-s not ,'claSsed^asvt--bxic-**''' come under this classification.^Cbissified under inorganic are toxic and/or irritant, ` w~-: j fibrosis-produdng and 'hod-fibrosis-pro- " whereas little or no fibrosis is produced ... ducing dusts. by the equally hard and sharp corn^ered r\:H.\Toxic and/or Irntani^Tbcsc an: . iY\l* ' aluminum oxide (emery)^ S5Je-T'2L'1?]t?Viinherently toxic when .inhaled,'"ingestpd'R_ o'r otherwise absorbed. j^mpn^Tfiem^are ~1116 dusts from heavy^metals andjthetr fdtowing^d^^-*"-''^--compounds, such as'^lM(d^inercury, [Cation, of . arsenic, cadmium, zinc." " ' "Sriateferrites'^ slwto *.7*.:*'. S' ' ' meters (9300 sq. in.) as compared with six square centimeters (.930 sq. in.) for the original block. If we assuml a dust . toncentration of 100 million partides to each cubic foot of air, the one. cc. of material will occupy an air space of 10,000 cubic feet . j.v* . .,12. With the exception of such fi- ..,; ; , .brous material as asbestos, die dust par- '' tides must be smaller than 10 microns ^ ' " '.. (one miernn equals one' twenty-fifth Figure 3. Granite nirficer in 'opention, without and with dust control Tbtovided. TX TINER r t V RMC0022762 ` .- * .-_:*.v~,tK . ; -yfeifc- ajgysa S^r^^-r.-.'ir '-1^'* ;*. XrX* l*-*T*f?'--'_;.`''"V.rifSS a?.k*L-. r: -, 7^7- ' ^i:>r. 2.rFibrosis - Praducm^Dtfitrr'za'he ^remdved " bpmeans','jjPr'dust ^valves '.,,most., important ofgithese .are-thg, igosj J^^agdcytesVwhichlngest lhe dusVpar- gamc, slightly solublj^flusts.. whid^fau^e ' __ j nw* fibrosis in the"lungs,'oUwhkn quartz is -'J the outstanding exampl? -- . ,,-_, - , -. . t.,.. :; ~--3h JVd~F^^^aS37<^^B&2tej cdlsynd .their^content^a^^ -Th--ese -ar--e i-n--ert, lar'idj~fbty-^t"t-d=n'--Be-h' f-eS' 's-'S'+fc"V`^`*,ilTs{DOrted Qirough these canaLsto seq-^A' .(dom if ever cause fibicous.'tissue^Jjut mat^*in ntlry"`reservoirs^ known ^^TympS^^ lie free, in the tissnes- or^, be.^abyirbcd, ~ Included are alumunMT/OJiadePcoal.' corundum, emery, ^l^estonc, gtapiesit^ '*g marble, plaster pans,-polish'of rouge, eft '*% ofParticles ., _ ........^----------- , The Respiratory System,,,.^ - -- - '***> Retendoo of Dust 17. In the homan^ep^nT^ tost '~!B tem, there are complicated moUfpass- Mrticle'through'still'air wfflvarX'mth *****5 ~ a--ge--s, o--n thi-e---w---a-l-ls -of w-vh:i.cih. jd.u~st.--particles the size and shape of the particle. ...... - fibers are the cause of the physical irri- will stick. Also, thejiose contains hairs fe.-ay.-v.-es* -i~i.v^'^"'''Ttation resulting in asbestosis.^ 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. . Brown has estimated the In order ^ that dust ., particles . - be inhaled, they must be smaif enough ?***&?" " The finer particles Igfjdust re -r-^i ' ter- float about inn the air or be carried main suspended in a still atmosphere for bjr'air currents. It has been shown by relatively long periods of time. Their research that dust particles must 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-tides also travel farther awijrfrom their 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 thi dust may be divided between the upper and lower respiratory passages has not been dear 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 mospheric dusts include a majority of particles smaller than this size, the par ticle size distribution of dust in the air is of little significance. McCrae showed that 70,per cent of the particles in sili cotic lungs 'were found 'to be less than one micron and that the largest particles 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. ' .'V * \'r V '22. In silicotic lungs, dust particles point of origin, and inasmuch as the larger particles settle out very quickly, the farther away from the dust source, the greater will be the percentage of smaller particles. 4 . '24. Neither upper nor lower size limits have been suggested for toxic sub stances, as lead, etc. It is Jhe opinion of Drinker and Hatch thafno physio logical size limits exist fdr^ these sub stances. r-.'iXipfiM-A ilv'-'' Silicosis . ., - ' a fever than the normal rate of about under 3 microns greatly outnumber those 25. 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, mechanism is responsible for this size named "silicosis." . V . .' we cannot select by any known exami nation the men best suited to dust ex posure, although some men show them grading. It must be realized, however, that considerable size grading is done in the air before the dust comes into con Definition ' '-, > '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. ' 1 . excess of small particles, 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 in the lungs simply because smaller par ticles 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 particles possibly up to 200 mi crons in length. However, according to Clark and Drinker, the most represen tative particle size in the lungs of men who have died of silicosis is one micron. to push any foreign particles of dust up ' rf2a. Fine asbestos dust particles ward in the direction in which the cilia . have been shown to produce only the bend, so that the particles may be ex inert reaction on the lungs characteris longed inhalation of fine particulate sil ica. It is manifested anatomically by formation of sharply defined fibrous nodules not over four to sixjnm. in di ameter, which in most cases'are uniform ly distributed throughout apportions of both lungs; and clinically by a paucity 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. Ic some cases, nodulation is concentrated in certain parts of the lungsj' in which casis symptoms may be marked." 73 -3 OX o O 1-3 IO CH K) 2 -J PI CJ\ 73 OJ pectorated. Dust particles which reach tics of other silicate dusts. It is, con .3x27. The International Silicosis Con the inner recesses of the lungs are also. sequently, believed that the asbestos ference in 1930 defined silicosis as a < W`0' :>/>*, r tow f____}ge .^^!e,.isf 'grounds^far^assuming disability,. L""'{"personToyer 40' show; some c. h'estj ers and Jonesjfthe Saranac Symposium i31`' Silicosis'may be detected by on Silicosis'm i93S.'gSit3'that, "From ray in* ech .of fhe the viewpoint of" etiology)* the', harmfulnes? of a given dust* containing' free sil- ever, X:ray appearances aloney are not sufficient for a diagn6sis''of silicosis. The The theory of the action.of' silica ica is directly influenced by the number complete "occupational and medical his- on theTungs'ls as follows t^tyhcre quartz of panicles of'free silica less than 10 tory of the em^Ioyee^hhould be care-' ' dust is inhaled and is passedjji^rough the microns in diameter that it contains." ! C\ -V V. Factors of Influence ' v \- 28. Silicosis becomes' noticeable after Tully evaluated and related to the X-ray '. findings before a~conclusion is reached, ./oi"l '.if*.TV* ? upper respiratory ttact, 'jjjjreadies tl terminal air sacs of the lungs .where the exchange of gases Bietween*the blood and'" air takes place. At this_ point,. as the widely differing periods of exposure to dust is'iT foreign'matter, if. b'ingested* silica dust, apparently depending on: by what are known "as "scavenger" cells a. The amount of dust inhaled. b. The percentage of free silica con tained therein. which carry.it through the walls of the air sacs to the lymph drainage canals located outside the air sacs.' This re The size frequency, or fineness of the particles inhaled. d. The nature and source of such other substances (including vapors and gases) as may be inhaled simultane ously or otherwise. " 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. "Tipure 5. An automatic bag loader han dling finely powdered silica dust. An effective local exhaust system is in oper- ... ation. sults in a rapid increase of tissue cells which narrows the lymphatic channel, hampering elimination, as*, it'is along these canals that foreign substances are removed. Also, when silica isjbeing re moved, the particle may kill the scaven ger cell by which it is being transported, with the result that all dust particles are not removed from the lung. Instead, they may remain along the course of the drainage canal. Apparently, these small particles of silica dust are' toxic in this 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. ' 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 the victim may be unaware in the 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 location and the tissue cells in the im mediate vidnity 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. v 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. . ` - 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. * 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 introduc tion of pneumatic tools." ' ' -/V'. Free Silica vs. Silicates /< \v 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 ments conducted both by causing ani mals to inhale dust over a long period of time and by injecting dust in their Third Stage: This stage may develop 34. Men with early first stage sili- peritoneal tissues have shown that sili- t9 U 0 0 3 W H _ aam *L x i v%. " v i . k> TKDUSTlUAirDVSTX _ _______-:>rl `OilT animal '- i.*r v' ; -rVsS "T"ti "I'gSr 1 aa?o*vfrkeie_s7ih:1c-a. -_ "number of Srtunity. tor' noSular* the actual ie its icw.*h*e-ni,wetx-p-<ors^-u.Tr*e _.Jttn limited JlaSS^^C^xd^' _--state-d_.'t.h__a_t ^e^S^tar^^tila'fiiipmdicate that, **aj^SsabiIng^lung^ondition is rfQ5.rSuit froin^exposures to sili- ^ usts^other~2bah asbestos), there idler ail unsuspected presence of free *rh-the. dust,' the. victim has had vious undisclosed exposure to free . dust, or there has been inadequate pretation of . the x-ray. On the other hand, Dreeson et al. have reported ^pneumoconiosis in workers exposed to |high concentrations (150 million par- lesper cubic- foot of air) of clean shed'mica.^' Greenb'urg and his coIKxsJ'ound'fibrosis associated with ympfoms as dyspnea and chronic ^i^4.^%_of'221 tremolite talc ners and^jnillers. These men were pfoyecs of 10 or more years ex- _ and the reported dust concentra'dcms' are as' high as 1300 million par ticles" per cubic foot of air. In two ^gunes in this area, Gardner had found quartz ranging from 12 to 20 per cent, but in the mills, where all rock is mixed and crushed, the dust showed low quartz percentages both in Gardner's studies ISgJ'and those of Greenburg. This subject of". Jhe possible action of silicate dust r^.g| bn^the lung tissue is being further in- vest'igated, and any indications that &' ^^t^b[.silicate dusts may be causing a -g^.jdfisabling lung condition should be f given^thorough study before' conclusions are reached. .Ui* r *-- . - -u. '. j^'r^Mixed Dusts *37a. Where free silica is mixed with \ other dust, the greater the percentage x'^^of-free silica, the less the dust exposure ,'*iarr required to cause silicosis. Since some Si?*-"ts such as gypsum have an inhibit-`V'"B:mg .effect, there is an increasing tend- ency to evaluate the extent of the * hazard presented by mixed dust on the -~ii??-basis of the individual dust exposure. ^ More data are constantly being ac- ' ~,^tumulated on the actual effects of vari- -' '.'v/Sr ous types of mixed dusts... J*.; -.'. J "'"T \r vV . Tir* ,?S `Figure 6. ` A tumbling barrel used foj finishing small castings. The barrel is inoper' ^'ration, but note the absence of dust due to a good exhaust system. Asbestosi i*l> *r '*!-."* - '.' - -i. i Ofc'swfc.; is to be avoided. S. The use of a. standard 38. Asbestos is the only silicate at based on the number of fine particles present recognized as causing pathology, result from the use of dust determina and even its reaction is definitely differ tion technique developed for the' study ent from that due to silica alone (Drink of silica dust exposures. Although fu er) . Its behavior is the exception to the ture research will undoubtedly set up a rule that silicates are inert, at least in standard based on the number of as uninfected tissues. Asbestos, when in bestos fibers in air, keeping the fine haled, produces fibrous tissues in the dust at less than the suggested standard lungs of both men and animals. As will keep the concentration of injurious bestos is made up of hydrated silicates fibers within safe limits. of magnesium with variable amounts of iron, calcium, sodium, potassium, and Infection t. ,: aluminum replacing portions of the mag 40. In the opinion of most investi nesium. The property common to all gators, the factor of infection is most of this group is the fibrous structure. important. It has been observed in It has been shown that the presence pf guinea pigs with chronic pneumonia fibers of asbestos are necessary for the that in an infected area which developed production of asbestosis and this fact, before exposure to dust, the local coupled with the observation that fine branches of the lymphatic system were asbestos dust is analogous in its inert not so efficient as those in the rest of the reaction on the lungs to that of other lung. Silica inhaled into tissue thus silicate dusts leads to the conclusion damaged appeared to accumulate in un that asbestosis is the result of physical irritation of the lung tissue and not of chemical action as in the case of sili cosis. ' usual amounts. " *. 2J** .1 " .. 1 - * '41. Since men with silicosis are more susceptible to tuberculosis than are normal men, there is often an excessive 39. Following a study by The incidence of tuberculosis among such United States Public Health Service of workers. Usually disability and death the asbestos textile industry, it has been of a silicotic, when due to pulmonary recommended that the dust concentra conditions, results from the'complicat tion be kept at less than 5 million par ing tuberculosis. For this reason, it is ticles per cubic foot of air if asbestosis especially important to have a re-em- K: 73 , S -3 OX o OH ro nj Z -J PI <T\ % cn ; : ..;a-s. ----s*jr*.-2# *.. fr '*** * r*^j : %* ~ 6--H.P.P.-4 -r. HEALTH PRACTICES' PAMPHLET NO. 4;J&- l-iai:**'* -pilo__y__m_mi-*f--tanjd*;vjai^:^^>ayJ:"progra-i*ni 'Jj r.iejd from lQ'to^^fw'cent 'Spending .u. mmomnuia,j'Ub--ro.nIcLhiiltiis.'vandi. among 'workers' SpbseiOoJ silica dust^on lengthof:embsureaH^dtSt'con'cen- ~kilments. the, p.res.ent tim-;e. -the-v't-r3e'2artcm'^e*n-t*o"f-tu-ber->. *-^posed, m<o_r_e.TthVa.. n_.^,2T5T,ye^atrhsatot tchoenrceenistraa-njm-pi--on>ayn*ir>.>-1>i,r-.-crstij culo:s,is m;s-u-icoti.c./sI-ub*jects iscompara'ble;vlions<gr-e-ate^r rtyha^nfa30^0rmniill:ion nn ,^pa; rrtti;crlle,,s --t.h.. an the onj.e ao,f-environm*e, to. that for ordinary^consumption SO - -T. . .---:-T~ t -that .pfindiyiduaJ suscept -'*%- > -ifc per mhir font nrair, linT " '" -' <-r-.-w years ago. - Tfae prospects are far from aS^. ^-ra^aLaiggaKgy-aSa^gg v-x- vestieators have noticed thai hopeless..^*Sflicbao||gHfially' being' j^?4& AccordmgjS^^^Russdl,^the _ ing!iri*the^ saine*Rlant,_at^t, brought under conSot^ilie.thne.is not' dlb^ty rate*amoing^itraate miners ^and m.Se.same workjila^ far distant when ^langefbus^amcehtra- ` from ^respiratory; tuberculosis^is^ about do not develop silicosis'to^ tions of silica dust wiUno longer be per-"'*^ ' ^'^Tgreef.' .flIt ;ise fpioess;Kibile fnor_*or ne*m. mitted in American industries. t Periodic be an early*victimj while theman examinations of those already employed ` ing beside him remains' compani will detect new infections in', persons ' free.1 This angle of the^ problem now silicotic. Prompt ^Institution ofr cates' a'need for further research*^ treatment will eliminate"*most of'the hopeless cases of silico-tuberculosis. Pre- * employment examinations will insure placement of men in positions that they can fill without damage to their health." -s. 50. It is well, nevertheless^ aider all coal mining as involving a to some degree, depending upon the of rock being drilled. While the hazard may not be as severe as in most metal Coal Mining ' - . 5 .. . 43. Anthraco-silicosis is a term used for a form of pneumoconiosis commonly called "miners' asthma."' According to Public Health Bulletin No. 221, "An- thraco-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 i-i 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. tess 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- Figure 7. A method of receiving dust into trucks and auxiliary collecting equip- ,j-- * * " ' -V' ?: v 4l/i 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. - vm*'. - 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'operadons, it is of importance at least because of the number of work men concerned. ivve-x. . - - ' -->1' -.l-i'-isrc.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 a|l 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' quany 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 hig^b. 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 r " ** sta1n#.d/.a-r*>d* 's. ' "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. .These 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 .. .. > . >7w , ' > TX TIM E R RMC0022766 'n^^tjSuj ^ ssfcig'v mZtVzffoXFbVST . SsS^te^ST^Hna^etC-T ^r^TmbecsiaLu'esyei^*W-^" - ^tfiSt5>,rofective'j-lhE5ppexueadTntq.the air the m.j jefectire- is the'^'w^^oSiged^KtjrStSeT Unfortunately' if ^dt^the du*S.J^^fe^^ne under ^T____f_1_fry iS t1 c*_ **^iT vws>. OSTwTtaMltlWoTwT.in..g "s^:deuce.wt_latte is far,more danger of' l -fc'VW^fr. r JJ^l^rAvyiv* X-'.<- !,r'- ;\* *v bemg^oisMSTijy inhaling toxicdusts'^^5?. _ Conditions arisin^from'Tllergic .- may P01* nieM<flhbiy; ttonxTiicr Hdunscttsc "mmuucrhh mmonrve rqmuiicrlkrllyv rough inhaling them than by swallow- nj, them. Dust swallowed with food gqes`'into the stomach from which the *major part of it is directly eliminated, fSome may be picked up in the blood dr- than byeatfigthon with'food or taking.' disturbances'of an occupational^ origin *t.ht_e_"m' ?in":;'!l!iq'1u.i:djs:. nB..u^t* aiill'*-_p__r_e__c'a' utions 'are coming more into prominence, from ^ should "be taken to prevent toxic dusts ''the compensation point of tdew.^^vl'jf from entering or even coming into direct' 1'-f" 1* -V.'..- "v^v-sR^-.jr;. rV' contact with the body. . t f 60. Persons said to beallergic are Jtz-.-.'sv . * -;,'V "those who are particularly susceptible to l4d., ? -> T;'v-' ... 'ircertain substances with which they come ftulation and then moved on to the liver. -SS. The practical problem in con-''"in contact.' These substanceTmay inThe liver, however, is ah effective filter nertion with lead poisoning is the pre- * dude foods, drugs, and vapors and dusts aidjdetraffier,,md it is only the poison . ymdon'of. serious lead exposure. The of; various kinds. Awide variety of : that gets beyond this point that enters ^general circulation. On the other hand, jjusts that reach the lungs can pass di- problem consists of two phases: one, the substances may, therefore, be respond- ^ determination" of the limits of safe ex- ble'for allergic reactions in various in-, . posure, '(see paragraph 68) and, two, the "dividuals, which substances' may have no -rectly into the blood stream, to the -^heart a. Vnd then* to . avll par4ts- of the body. "^-SS. Alice Hamilton, in "industrial ^.^-'.Toxicology" (Macmillan Company) - points out the distinction between the two ways in which poisonous dust can be taken into the body m the following paragraph--"A great deal of money has been wasted by well-meaning em ployers who sought to protect lead fur- reduction of lead exposure below these * effect on others or, in some cases, may limits, .VCi/ ^,Vv.*<f-`;even be of positive benefit The types '.i5J6T. '~Wre"must r7ecognize how^ever that lead is a normal constituent of a living 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.) Mi ', . /.ii `j L , 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. of reactions experienced by affected in- dividuals to given substances may also vary greatly both in nature and in de gree. 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. -. . ' .. t 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 pillows without suffering acute attacks. Hay fever is another type of reaction to dust 58. The symptoms are chilU fol on the part of certain individuals. These lowed by a malaria-like fever which usu dusts are frequently in. the nature c` ally passes off within 24 hours, allowing pollen, as from plants. Hay fever, it the- worker to return to his job on the claimed, however, may also be caused b 7) , 5^ OX o O -3 NlO> 2 -a F O' ? following day. The first attack usually other types of dust. In any event, th ~'J immunizes the victim so that attacks are precise manner in which an allergic ic not experienced consecutively. How dividual may react-.tc a substance t .... ever,' after a lay-off or an absence from which be has become sensitized canno contact with the dust, a further attack be predicted. is likely. Slow, deep breathing, accord- figure 8. Vtew in an iron foundry show- . - ing bench grinde.rs wi i.th ex-haus t hoods. .'/ ' - . . ? ' - A- - . .- ing to'Drinker and Hatch, seems to ; bring about the symptoms more quickly. , 1i, ' 62. Many believe that allergic in dividuals are bom with their particula: 65. _ ^s, the. result. of .mauy^yea _ . -practical experience in' du^iSrtoofjn1 ` the South African gold mmesyS^ncen' :tntion bFbine'mgi of'dust*perrcubic* meter of air was accepted asrsta and is now known commonly`as South AfricatTstandard." ljjfi$1934, I^r G. Irvine stated that no miner^who had^ entered the industry since thislow con- '*"u centration had been maintained had, as' ~ yet, contracted silicosis. 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. .ciiJui-jc'--, -* `-*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. '- i* 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 v- -.-**-/--* TV- . -- -rjT*. 'H.' 66. It'-was stated by D. E.'Cum mings in a paper presented at the Second Symposium on Silicosis at Sar- tmac Lake-(~ ? . Information from .field studies 1 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 his health if , the concentration did not exceed five million particles per cubic foot of air." =. - 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 pheres. Dr. Gardner continues further: .. "Not enough is known about 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 dust I would very strongly oppose the recom mendation that protector dust be nsed to attempt to prevent silicosis at the present time. But I 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 which are 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 be TX T IN E R RMC00 227 68 .. ' . ^wj.^vX/Ui 1 _ ---.'- ri*; * --*. kjgr- < Sowledge in a' i'^^Manganese*:;750 p g7p>7cubic meter_ ^ `have _ Jor- spe- t-iSifT.?* Control 'of'Dusdness as. follows: *s*v -.H-reeaclVth=-J:: /United .*J^g70.-iTliere are various ways in which T'c*)"fiye.mil- 'dust diseases and 'annoyances may bft- i particles p g^favdtded*: ,&&&$&& rr^#ys-- _ , ^cSTdop--(R41 J^ersT'et aL) 50.- r000,000 particles pc cnJjiiTfoot fo'r coal 7^'dust* containing ' n r\S% quartz. 10,000,000 to 15,000,000 particles for dust jivith 13% quartz, and/SiOOO.OOO to 10,- \L; 000,000 particles forchard rock'workers ^exposed to dustjcontaming,' 35% free te avoidance pf exposure^furnishes . t^f^the firsthand most important defense ' .-^.against * industrial/ `disease. `Job* //' -ji'-should be' performed in' clean air as ' ^ far as possible.' It Is not necessary, ~~4.-_.4z- however, to prohibit all exposure to a toxic substance, as the human sys- '.'silica: . %* :4Li~-r_rjgnxp^pl JtlrsHlO ` _ g^v.t-Lead--(Legge and Duckering) more IV than .5'mg. per cubic meter is hazar- /j-ldous and (A. E.* Russell et aL), less 7: than .15 mg. per cubic'meter 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- pR^- 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 die 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.). _ centrations cannot be sufficiently re- . dueed to constitute an otherwise safe condition. . . 4, 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. . . . timing no quartz, for wheels made from natural sandstone, which is about 95 per cent quartz. ' 8.7 A final method of protection is .the -wearing of special protective equip"7 . ment by workers. This step is fre quently the last resort and is used ~--only 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.) *: :!>3JdU5rie*; 71. In many localities codes or or 4. The substitution of 'wet methods ' for original dry methods has ex- ,, . erted considerable control over dusty atmospheres. Dry drilling is ': the cause of considerable dustiness . in mining, which may be greatly re- ' v duced by wet drilling. This is also true in many construction and quarry jobs. dinances for the control of'dustiness are in effect which should 'bet investigated and followed by employers' seeking to improve working conditions.'- ' t-1.- - - s-i* ojgfc *qc>i~ r Lvjqd'tigCtlT ;:*. Local Exhaust Systems-j>(_ 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: " - -v rjk. 11 . ` - " *<* a. Exhaust hoods jnv . v .. b. Piping or ducts *1. -.-j : c. Air cleaning plant d. Source of suction I Off" -r`\. ` +.**V'r;` F'*Vv' 4Vn r 73. While each of these parts should be designed and installed to perform its .6 The routine recording of dusty con centrations is a valuable check on the existing exposure. Periodical counts of air samples are a great help in showing whether or not there is need for further control. , required function with respect to the system as a whole,' the/exhaust "hood probably demands the most careful de sign, inasmuch as the degree^tif control secured depends to a large^ertent upon the shape and location of tHbnood-^and 7. In some cases, (he application of the rate of air flow to it^Ffian upon any general rather than local exhaust other single factor. Ji ,, ventilation is desirable. There are ; instances where the source of pol 74. Hoods have to a consperable ex luting materials is constantly chang ing position and local exhaust bet comes difficult and impracticable. 7 Here a general ventilating system tent followed the desigp n^*empIoyed in such industries as'woodworking and metal grinding. Howev^?S noted by : . may be the only answer. ' - .Theodore Hatch, in recg^Sra the in- Courtesy. E3rk and Blum Manufacturing Company " V. : -'-v . . Figure 11. Exhaust system for removal of lead dust and fumes. -- : . 7 f~fj&""-*-d"u*s*trial dust probIemrS|jtWfriimH hy- TUliseteeidghint mtheitshoodrsdoefr'pli>rev"eInndtiounatgfliavel nMheedrle- gien,ic andKemciotantoinmnice^ ^mtirely be- due" by Clark and Drinker, published by the yond the limitations indus tries National M. edical Book Company. Inc.. New ^ whicjj ^ production York, N. T. 'V>j tr" ' * has been .; , liv 7 TX TINER RMC00227 69 rfc*S-* ;J. f^r io--H.P.P.-4 P/L4Cr/C5' Valnuisance ius!tiekfth of-dust production must be'under ab- v hazard." jOccupatio" /diseases?" haye' come to .mean so^much .Wpnoustry m medical costs and compensation as^well " ` .. Proper"design ana location of the ' as? the health of-WOTku^that/there^is suction opening and the rate of air'flow ample justihcation'forextensiTe research ^".into it is a matter of 'utmostJn^ortancer ^ and investigation iSt^.dweiopment Of - liws governing the flowji^air'into ex- '^1 the best ppaibl^^^K^^^bgl'eir^;' 'v haust openings have been given'in '"In- dustrial Dusts" by Drinker ahtfHatch:* % 75. To maintairPa safe concentration - -^//Enclose the process as . completely .;.Sjp#*.s possible and provide internal baf- of dust in the vicinity of dust generating j^Bes to guide the air-flow "where'it equipment it is necessary to introduce i-'-'f.is most needed. sufficient clean air from the outside to dilute the dust-filled atmosphere to the degree necessary for safety. In the util ization of general vmtilation systems, care must be taken to' avoid excessive exposure of workers as dust is removed from its source. Especially where local . 2U An exhaust hood which .does not ^'-`./enclose the process should be placed with its opening as close as possible 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/' 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. - ;4;. ';irVs ; 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 phere. Proper hood design will make 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 "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. * r> * 4. Provide flanges wherever possible " to reduce the air flow from inef fective areas where no dust is pro- ' duced. - - 5. Locate the hood opening, or part of it, so as to receive directly any dust that is thrown off along a well- defined 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 "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. .-*di1 - ..... Figure U.'Sweeping with'the use roiled sawdust to allay dost... Wet vs. Dry Dnllmg. . -78. On the matter of ^drilling, Har rington says: /-*- "Dry drilling is, of cotirse, very much more of a dust producer than wet 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." - - V:-- 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 "t, gi'C-l'M*- of relying upon th< ------------ . --- 5' current to dilute and transport the in~ ^ Committee of the National Safety nr: - . jurious materiaL Small units are now^iUs;!n:yit&gJkir`pamphUt, the mC`PubUi%dtk ?ervice> - thorshave reviewed carefttUv the litera-' Cenrai Motors Corporation; SK. C. :