Document 3QQOxy2a49jKY11Zk527BKa1J

FILE NAME: National Safety Council (NSC) DATE: 1939 DOC#: NSC232 DOCUMENT DESCRIPTION: NSC - National Safety News - Industrial Dust Health Practices Pamphlet No. 4 Industrial Dust Published by National Safety Council 425 North Michigan Avenue, Chicago 11, 111. Industrial Dust 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 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. 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. Silicosis increases suscepti bility to tuberculosis. 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 a b s o r b e d 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. d. A reaction, allergic in nature, caused by breathing organic dusts such as pollen, flour, certain pulverized w oods. e. An increase in bronchitis and other acute respiratory infections by breath ing inert, non-fibrosis-producing dust such as coal, emery, limestone, marble. 3 In each of the above cases, the inhalation of dust can he the sole cause This pamphlet is one of a number of Safe P ra c tic e s and H e a lth 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 copies of this pamphlet are avail able. Member price, 45 cents each. Quan tity and non-member prices on ret/ucst. "lung," "dust" and "abnormal condi tion." The present generally accepted meaning of the word involves the con cept merely of "dusted lung." The kind of dust inhaled determines the type of injury noted in the lungs. However, there is one pathological process which underlies lung disease caused by dust. This consists of a fibrosis or a replace ment of the elastic tissue of the lungs by an impervious . car tissue. 6. Research on pneumoconioses has of disability. With the toxic dusts, been carried on in the North Amer ran trouble may result from swallowing or continent more actively in the past more rarely from skin absorption, as well decade than in any other period. The as from inhalation. Inhalation, how hysteria with regard to silicosis and ever, is by far the most important other occupational diseases has now means of absorption of industrial dusts. largely subsided, and the subject is be ing more carefully considered and more 4. Irritation and ulceration of skin soberly judged. and mucous membranes may be caused by such dusts as lime and chromium The Problem compounds. Pneumoconiosis 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. 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 (he effect of various kinds and amounts of dust to which workers are exposed. F i g u re 1. D u s t c o u n t i n g by si.inti.irti light field methods. Origin and Properties Physical 9. D u st is formed by reducing solid m aterials to small sizes. Processes like Copyright. 1929, 10.IQ. Xntinmi! Stifcty ( 'vuitcil. HfROLE? NIX a fSSOC.. ID :1-903-645-5228 OPR 1 7 '98 9:20 No .003 P.09 2-- H.P.P.-a h e a l t h p r a c t ic e s PAMPHLET H O . 4 Figure 1- Left; Operator <0 rw aamte i using pneumatic banker. Neither dust coutaol ro r respirator h n bom pro vided. Right; The same opcrsrioo with goggles and du.*ntrot bend In use. grinding, crushing, blasting ad drilling produce dust particles of sixes from the microscopic to the visible, tb d r composi tion being the same a s th at of the parent materials ff n o t altered chemically d u r ing the subdivision. Frequently the percentage of some b a r d miner! such as q u aru in the fine dust rosy be less than that in th e parent material. Common cam ples a n th e ^mineral or Inorganic dm ts derived from th e disintegration of rock and the organic dusts like wheat and flour. ' 10. Smoke from burning carbonace ous fucks--coal, 0, wood, etc.-- con tains droplets as well a s'd ry particles. Tobacco, for instance, produces * wet smoke composed of m inute ta tty drop lets. T he p artld e size of tobacco smoke b about 0_ZS microns. l i . W hen a solid la broken into finely divided particles a n d released in the air, one of the im portant changes that take place is th a t th e space occupied fay the broken m aterial an d also the sur face areas at increased m any times from that of the original mass. For ex ample, If ooe cc. (.061 cu. in.) of quartz is crushed into particles one cubic micron m size, there will be 10** (1,000,000,000,000 or one trillion) particles with total surface areas of six square meters (9300 sq.' in.) as compared with tix square centim eters (.930 aq. fas.) for the original block. I f we assume dust concentration of 100 million particles to tech cubic foot of air, the one cc. of material will occupy an air space of 10.000 Cubic feci. thousandth c! *n inch) in their longest dimensions in order to enter the inner recesses o f the lungs where the damage is caused. It was formerly believed that the hardness and sharpness of quarts lianfcks were deciding factors in the injurious properties of dust, but this view h z s been generally disproved. (See paragraphs 20 and 29). Hay fever and other allergic types of disease from or ganic dusts or larger particle sices can be caused by breathing panicles into the nose and not having them reach the lungs at all. Ragweed pollen is fro m Id to Z5 microns in diameter. 13. By comparison a healthy red blood cell is about 72 inches, and a white cell up to about 16 microns. A person with normal eyes can see an ob ject SO microns i s diameter. However, the reflection of tight from a shiny parride of quart* may be seen when the particle b as small as 20 microns in di ameter. I t is to be realized, therefore, that individual dust particles small enough to reach lung throe are essen tially invisible to the naked eye. 14. Fosses may result finta any of - " **1 or ^ysi^kem ical changes such as xfnc oxide, formed when bttnuag s a c vapors arise from molten brass, or lead occurring in the exhaust of a motor ear burning gasoline contain* tog tem -ethyl lead. Chemical IS. T he chemical and mmeralogical make-up of the dust are the deciding factors in determining its injurious properties, f t has been shown that sili con dioxide (free stEca) in the fonn of quartz may produce a disabling fibrous, whereas b ale or no fibrods b produced by the equally bard and sharp cornered aluminum oxide (emery)- Classification o f D usts 16. The following classification of 12. .W ith the exception of such fi brousmaterial as asbestos, the dust par- smaller than 10 microns (One xniernn eq u als one tw enty-fifth dusts, according to their physic} ch ar acteristics and physiological effects fcai been arranged by Dr. R. R, Sayers: ^ o r g a n ic d u sts " v A. Non-Living O r tu ie Uuu> At the name implies, these are con, prised of Mm-viable p u lid u which may or (nay m i he either toxic or iirhuu, hue ncvertheieiis have effect on the human organism. 1. T erif w Irriiem Dvr/;. These arc organic dust* which produce un toward symptoms cither systemic or lo cal. Those producing local symptoms are described as irritants, while those producing general symptoms are termed toxic. A dust may be both toxic and irri tant. 2. ritfrrgU. ( S paragraph S9.1 H. liv in g Organic Zhnir These duns contain particles capable of reproduction or snultiplicatioa, such h bacteria and fungi. They arc usually found in low concentrations and asso ciated with aon-tiring duns in the air. 1. Bacteria. One of (be most im portant is the anthrax bariUus. which is (end in the dusts from skins, fu n , wool, and animal hair, b m a hoofs, b o m , etc. Diphtheria, tutMroriosiabpbmd and other barittus-prodoccd diseases may result . from exposure to aofeered dusts f i t o s terial-sensitised dost can also be the ^ cause of allergic diseases, as asthma, hay fever, eczema, migraine beadachex, etc. 2. Fungi. Duett p w tia ia i parasitic fungi may esuae anoyance stud discom fort. Mould on straw, hay, grass, vege table debris vs typical of this type of dost. C, inorganic Dotns These are of a u e n l origin not re quiring a Uring Organism to produce them. Many darts not e&sscd u toxic come coder this h r ik o M s CUsrified under inorgame are lo w and/or irritant, fibrosis-producing and non-fihtosis-productng dosts. 1. Toxic and/or Irritant. These are inherently toxic when inhaled, ingested Or otherwise absorbed. Among than are the doati from heavy metals and their compounds. Swell as lead, mercury. 04/17/98 11:23 TX/RX NO.1994 P.009 HAROLD NIX & ASSOC.. ID: 1-903-645-5228 OPR 1 7 '98 9:21 No.003 P.10 in d u st r ia l o u st 2. F\bfans - ',,trip Uum, The M l important o l th e * arc the inor. n n i t . fhghtiy xolubte tfu tli, w(licit e lu te ibrnnt in the tune*, of wliieU n u tm it the e tiic lv td tn f exam ple. J ,Vt>n f l i f O W f r o t i n t i n g D m i i l . Thc are inert, and by th<mwU'tt teitam ii ever cause Rbrotii <*<, but may he free in tit tiitu tt or be absorbed. lacM nf arc aluminum title, coal, cvnmilum. emery, luneatone. ma$Hti(t marble, plaster parts, polish of roufe, etc. removed b y means of d u st valves (phagocytes) which ingest the dust par ticles and carry them to a system of fine drainage canals called the lymphsue*. Both the cells and their contents are transported through these canals to sed imentary reservoirs known as lymph nodes, r- S lro o f Rarucfcs 20. Microscopic dust particles are, The Respiratory System of course, attracted b y gravity, but be Fipire 4. Ground Aka dumped cm Retention of Dust cause of the high resistance of the ait, the smaller dust particles settle out more (w p*w of a (Mtnror. Note the ma cIokc AMmeywyifciw freed tad! the uk of *a approved rc*puter by Ac operator. 17. Jo the bum* respiratory sys slowly. The settling motion of a dust tem, there are complicated moist pass ages, on the walls of which dust particles particle through still a ir will vary with fibers are the cause of the physical irri vrin stick, Also, the nose contains hairs the sire and shape of the particle. tation resulting in ubestosZs. whldb catch some dusL. However, the 21. In order th at dust particles 23. ' T h e ' finer p b tk fe* o f d o st to- respiratory system can become over be inhaled, they must be small enough fm am suspfflded fe astGi atmosphere for loaded with dust, and when this hap to float about in (he air or be rarried relatively h o g periods ot_time.. T heir pens, th e dust catching mechanism by air currents. I t has been shown by chances o f being aahaled.eep'i&erefore,' functions poorly. research that dust particles must be *re*t(r increased. The m tefierdost par- 1 1 C. . Brown has estimated the smaller than 3 microns In diameter to tide* b o traw l farther way fromdhdr- average amount of dust a norm al m an cause sflioems- However, since all a t point of' origin, ad wwaroud r ns ib c will retain. Breathing a t the ra te of 20 mospheric dusts include a majority of larger particle* aettie oufa-.very quickly, respirations a minute, fo r example, he particles smaller than this size, the par- th e farther away in to thrlfttsr-aoerec, nil inhale about 10 liters a m inute an d tid e size distribution o f dust in the air nbe greater t be the pereentage1of retain 60 p et cent o f th e Inspired dust, is of little significance. McCrae showed , smaller partides. ft is estimated roughly th a t th e retea th at 70 per cent o f the particles In sili cotic lungs w e found to be less than 24. Neither upper nor lower size rn o f common silica d u st is about SO one micron and (bat the largest particles limits bave been saggested for toxic sub x r cent, but the way this d u st m ay b e did not exceed 203 microns in their stances, as lead, etc. It is the opinion frvitied between th e upper an d lower respiratory passages h as no t been d ear- greatest dimensions. Results since ob tained by other Investigators have of Drinker and Hatch that no physio logical size limits exist for these sub- y defined. Drinker has observed In the served to substantiate this comparative itances. nrsee*othfinmge, tpaol sfsuimbley ffeivveerotrh asitxsblorwea, tdhesepa ly early statement. Siltcvsis olfurte, is much more likely to produce 22. In silicotic lungs, dust particles , fever than the normal m e o f about wader 3 microns greatly outnumber those 25. Undoubtedly the most important 5 breaths a minute. This is supposedjr due to the higher retention of d u st re* ulting from deep breathing. However, of larger dimensions. Some have be lieved that the human respiratory' mechanism is responsible for this sire kind of lung disease caused by the In halation of dust is that wbidi has been named '`silicosis." re cannot elect b y an y known xamistiM the a m best suited to dust er asure, although some men show thenv etves obviously unfitted for d u sty a t mospheres. 10. T he way In which dust particles re removed from the respiratory tract as been described by D r. A. C. Barclay, ritish specialist on X-ray. T he bronchi r respiratory passages, are covered with number of tiny, hairlike cilia or tniroseopic whip lashes. These cilia make fast stroke in one direction and a ower return stroke. They cover the usages leading to the lungs, and all tep in time with each other. This tends *push any foreign particles of dusl upard in the direction in which the cilia ifld. so that the particles may be exretorated Dust particles which reach ie in n e r recesses ( th e lu n g s a r c a ls o grading- I t m ust be realized, however, that considerable sice grading is done in the air before the dust comes into con tact with the respiratory organs. An excess of small particles may be found In the lungs simply because smaller par ticles remain suspended Jaeger 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 D ark and Drinker, the most represen tative particle site In the lungs of men who have died of silicosis is one micron. 22a, Fine asbestos dust panicles have been shown to produce, only the inert reaction on the lungs characteris tics of other silicate dusts. It is. conM<)urni)y, believed that the asbest".- Definition 26. Dr, Gardner's definition of sili cosis is as follows: "Sdcosij b a chronic disease of the lungs resulting from pro longed inhalation of fine particulate sil ica. It Is manifested anatomically bv formation oi sharply defined fibrous nodules not over four to six mm. in di ameter, which in most cases arc uniform ly distributed throughout all portions of both lungs; and clinically by a paucity of symptoms and physical signs that usually appear only in the late stag of the disease and by a tendency to be come complicated by tuberculosis. In some cases, nodulation 1$ concentrated in certain parts of the lungs. In which cases symptoms may be marked." 27. The International Silicosis Con ferenre in in to defined silicosis as a 04/17/98 11:23 TX/RX NO.1994 P.010 INDUSTRIAL DUST H.P.P.-4 5 cate dusts are inert and do not cause the characteristic nodulation produced by free silica. In addition to the animal experimentation, men who are exposed to silicate dusts containing no free silica have been x-rayed, and in a number of cases there has been opportunity for examination of their lungs. The nodular appearance on the x-ray and the actual nodules on the lungs, both of which are characteristic of silicosis, have not been found when exposure ha been limited to silicates. Gardner has stated that evidence so far available indicate that, where a disabling lung condition is alleged to result, from exposures to sili cate dusts (other than asbestos), there is either an unsuspected presence of free silica in the dust, the victim has had a previous undisclosed exposure to free silica dust, or there has been inadequate interpretation of the x-ray. On the other hand, Dreeson et al. have reported pneumoconiosis in workers exposed to high concentrations (150 million par ticles per cubic foot of air) of clean washed mica. Greenburg and his co workers found fibrosis associated with such symptoms as dyspnea and chronic cough in 14.5% of 22 3 tremolite talc miners and millers. These men were all employees of 10 or more years ex posure and the reported dust concentra tions are as high as 1300 million par ticles per cubic foot of air. In two mines 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 and those of Greenburg. This subject of the 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 given thorough study before conclusions are reached. 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 ing 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 tvues of mixed dusts. figure 6. A rumbling barrel used for finishing small castings. The barrel is in oper ation, but note the absence of dust due to a good exhaust system. Asbestosis 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 stu d y by The United States Public Health Service of the asbestos textile industry, it has been recommended that the dust concentra tion he kept at !e>- than 5 million par ticles per cubic foot of air if asbestosis is to be av'oided. 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. 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-ern- HAROLD NIX a ASSOC.. ID: 1-903-645-5228 APR 1 7 '98 9:23 No.003 P.12 UL.iJ.TH I'L.U I H r t M J ' / n 1.1 N O . 4 "pathological condition of the lu n p due jo the inhalation of free silica (SiOj)." Other authorities have given various definitions. T h ai given by the American Public Health Association includes the stalestcat th at silicosis is "a disease due to breathing air containing silica.** Say ers and Jones a t the Saranac Symposium on Silicosis In 1935 stated that, "From the viewpoint of etiology, the harmfulness o f a given dust containing free silk a Is directly influenced by the number of particles o f free silica Jess than 10 microns in diam eter that it contains." Faeroes o f Influence 23. Silicosis becomes noticeable after widely differing periods of exposure to silica dust, apparently depending on: a. T he amount o f dust inhaled, h The percentage of free silica con tained tin-rein. r. T he rice frequence, o r finenett o f cfc panicle* inhaled. A The nature Sod source ( such other rufrftanees (including vapors and C*tes) as nay he inhaled simultane ously o r otherwise. . The paw n of resistance of the mdividoa! concerned. f. The presence or absence of a eomjdicaiion try an infective process. C- The presence of complicating condi tions such as high temperatures or humidity, and unfavorable posture*. Physiological Effects 29, In artier years it was believed (hat the physiological action o f quarts Wi th e lungs was caused by the hardness of (ho material. In fact, It was claimed Chot toon who worked on sandstone were harmed pot only by the sQks particles, but also by sharp hits of steel. These Ideas were contradicted by U r. L . U. Gardner, of Saranac Laboratory, who showed th at silicon carbide and fused aluminum oxide, both of which are harder than quart*, had practically neg ative physiological effects when inhaled. D r. Gardner also showed that dust from the diamond, the hardest substance known, was practically inert when inbaled, 30. Stliaosls is considered In three separate stages by medical authorities: First Stage: The A if< here pro duce* no disability and doc* no apprecia ble harm. T he affected man can carry on hi* operation* a i well at ever. Second S tage; Respiration it ffeeted. TK. victim maty be btb<fcf by labored breathing 'T h i r d S < a t T in * t a c t m a v tl<v<l,ai- toilo" me ilif .<i on.l in,;, , , , ii,< virurn lia l-ern rtiiwtvrrf I..- aifno-plicrc. H r r r UJxi'fW b m i l i . n t l,r- r o ip c .r\rrr and 111 iftpirnf ttr-on i- tuKcp>:ii*c pulm nnart l:tl-rtriiln.>., costs, in the opinion of the Saranac Sili cosis Symposium, ate out disabled and axe not a menace to their fellow em ployees. The fart that barely percepti ( re q n e rtih -*uli fatal tentili.. T V ,, r U ble X -ra y change Is visible a n ot S r is Bi'tv f a t brio, turinal. bit virimi to rr-piratnry ,i | u o . j . - grounds for assuming disability, since most persons over 40 show some chest 31. 5iIico*is may be del evictI bt X- - changes regardless of dust inhalation. ray in each o/ the three stage*. How ever. X-ray appearances alone are not sufficient for a diagnosis of silicosis. The complete occupational and medical his tory of the employee should be care fully evaluated and related to the X-ray A ction o f Silica on the Lungs 3S. The theory of the action of silica on the lungs is as follows; Where quartz dust is inhaled and is passed through the upper respiratory tract, it readies (he finding* before a conclusion is reached. terminal a ir sacs of the h a p where the exchange of gases between the blood and air takes place. At this point, as the dust is a foreign matter, it is ingested by what are known as "scavenger" cells which c a n y it through the walk o f the air sacs to the lymph drainage canals located outside the air sacs. This re sults in a rapid increase of tissue cell* which narrows the lymphatic channel, hampering elimination, as It b along these canals that foreign sub stances are removed. Also, when silica Is being re moved, the particle may UD the scaven ger ell by which U b being transported, with the result (hat all dust particles are Fapute 1 . An automatic bag loader han dling finely pnwdrrcd lie* dim . An effective lucrl exhaust system is in iter ation. not removed from the lung. Instead, f they may remain along the course of the drainage canal. Apparently, these small particles of silica dust'are toxic in this 32, From most industrial ntjteriencc the development of silicosis may not be anticipated short of five years. A few cases have bees claimed to develop in as short a period as one and one-half years, bu t these were under extreme and onusual conditions- T here has been evi dence that alkaline materials, such as soap powder, accelerate (be 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 iilicosi* cannot be cured by any mean* ye; known and in its advanced stages is frequently complicated by tuberculosis or other infections, the importance of location and the tissue cells in th e im mediate vidnitv are altered and re placed b y what k known as scar or fibrous tissue. The ultimate resuit is larger areas of tissue or hmg volumes in which capQhuy action is definitely re duced--- through which a -norm al ex change of gases between the (flood and inhaled air cannot take place. 3 6 . As the Inhalation of titics con tinues, the amount of fibrous tissue will, of course, increase, with the ultimate re sult th at the lungs win not readily oxy genate sufficient Wood for the. body need. This produces a shortness of breath in the affectco individual in pro portion to the amount of scar tissue in Ms lungs. Free- Silica vs. Silicate* prevention is apparent. Also, in many 37. W ith the except',* of asbestosij. industries, new development* have the silicate dust# have not been shown greatly increased the dust output. In to cause a disabling lung condition such granite stone cutting, for instant, and as is produced by free silica. Experi- ^ in rock drilling, dust production in ments conducted both by causing ini- creased tremendously with the itmnduo rials to inhale dust over a long period tion o< p n c lj ^ f K tOoU- of time and by injecting dust in their 3*. Men wih rx rlv fu M an --i peritoneal tissue- h iv e i^ow n th a t sili- 04/17/98 11:23 TX/RX NO.1994 P.012 HAROLD NIX & ASSOC.. I D :1-903-645-5228 APR 1 7 '98 9=24 N o .003 P.13 m d u st h ia l dust H .P .P .3. o ih ^ r cm n p o n cn ii of (rm cnt nidi tivsi s m 10 n - v i prcuecnul *U olfict pt. * o m i n i ' b f l i * o H | o s c ftr (Jk -ic . iji\td u a l> ipfi.trontlv fc .itm l li.c jm c ..I flfrm.. I. . A l i h o u p 'l t < *. il.at it\v aCf- v , ftfctitt- j - f(tf rW.1lIV* IflH.UIMS ,.f -tl,,.;, <n ||,v ,j,,,| die liniMs r.i irtlcfltKW luve not been defined. Therefore, the limit for silica iMinide I * than |0 ndtron* in -liam clcr ai il.c brcjlhini; /.in.- Has arlMlrarily set At five liljhni f.an.Wi.- Ier cubic iu n t {,( air a - dctcritiin vl by '>t Vnin-il 5 > 3 ici Public M.:.liti S,r-.'- tre v ia n ib n l l>elii field rMiiu.*' nacemen, white lead giifidefi, etc., against poisoning, by providing bath and lunch rooms, clean overalls, mouth washes, and such, instead ttf preventing the cscafie of lead into the air the men were ubliged to breathe. Vntorfunatelv this has sometimes been done under a physician1* advice. I t must never be forgotten that the great majority of in dustrial poisons enter the body with the inspired air and that while a workman eats only-three times a day. he breathes 16 times a minute during the right or ten hours of the working day/* Figure 0. Du collector units riauru.I im i h r rtHif. Toxic Dusts -Breaching vs. Swallowing 54. Numerous authorities give evi A J lc rg ic Disease* dence th at there h far more danger of ) bring poisoned by inhaling unde dusts 52, Generally, workers may be poithan by eating them with food or taking soned by toxic dusts much more quickly them in liquids. Bui all precautions through inhaling them than by swallow- should be taken to prevent toxic dusts ing them. D ust swallowed with h od from entering or even coming into direct goes into the stomach from which the contact with the body. m ajor part of It is directly eliminated. Some may be picked up In the blood cir Lead culation and then moved on to the liver. T he lite r, however, is an effective filter and detoxifier, and it ts only the poison that gets beyond this point that caters general circulation. O n the other hand, d u sts th a t reach th e lungs can pf di rectly Into the blood stream, to the heart an d then to 11 parts of the body. 55. The practical problem in con nection with lead poisoning Is the pre vention of serious lead exposure. T he problem consists of two phases: one, the determination of the limits of safe ex posure, (see paragraph 68) and, two, the reduction of lead exposure below these limits, 59. Conditions arising from allergic disturbances of an occupational origin are coming more into prominence, from the compensation point of view. 60. Persons said to b e allergic are those who are particularly Susceptible to certain substances with which they come in Contact. These substances m ay In clude foods, drugs, and vapors and dust* of various kinds. A wide variety of substances may, therefore, be responsi ble for allergic reactions In various in dividuals, which substances may h a te no effect on others or, in some cases, may even be of positive benefit. T h e types S3. Alice Hamilton, in "Industrial 56. We must recognize however that Toxicology" (Macmillan Company) lead is a normal constituent of a living points out the distinction between the animat and that there is a level of lead two ways in which poisonous dust can absorption which is safe. Lead intoxi be taken into the body in the following cation and lead absoiptioo can be pre paragraph--"A great deal of money vented by engineering methods. (Sec has been wasted by well-meaning em Health Practices Pamphlet No. 3 and ployers who sought to protect lead fur- Safety Instruction Card Xo. 116 on this subject.) o f 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 attack*, and in a third case cause a skin eruption. Still another person may be affected in all three ways. Metal-Furoe Fever $1, Metal-fume fever may be one of the results of breathing dost from metal sources. This malady usually follows contact with a heavy onccntmkm of magnesium onde, copper oxide, lead, tine oxide, and possibly lead oxide and manganese dioxide. 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 pillow's without suffering acute attack*. Hay fever is another type of reaction to d u st F i);u n t . V ir* ' in jrj in m f.HimJn' d w in^ hrful, ,:r.`r..l. r. is . 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 immunixes the victim so that attacks are not experienced consecutively. How ever, after a lay-off or an absence from contact with the dust, a further attack ;< likely. Slow, deep breathing, accordin- to Drinker and Hatch, seems to tirln " ab o u t th e sym ptom s m ore quickly. on the p an of certain individuals. T h ese dusts are frequently in the nature of pollen, as from plant*. Hay fever, it is claimed, howvet. may also be caused by other types of dust. In any event, the precise manner in which an allergic in dividual may react to a substance to which he has become sensh ire d can n o t be predicted 6?. M any believe th a t a lk r- 'ic in dividual* are^horji_w}ll?./brir partirul.n 04/17/98 11:23 TX/RX NO.1994 P.013 HAROLD- NIX &- ASSOC. . ID:1-903-645-5228 APR 1 7 '98 9-`25 No.003 P.14 6-- H .P.P.-4 HEALTH PRACTICES PALI PH LE T H O . 4 ployment and periodic x-ray program ried from 10 to 11 per cent depending m onia, bronen/us and similar physical among workers exposed to silica dust. on length of exposure and dust coneen- ailments. 42. Gardner states as follows: "Atctridileinocne--bLeihncg hfioguhnedr apmerocnegntawgoerskeorfs eixn the present time th e treatm ent of tuber posed more than 25 year.; (o concentra culosis in silicotic subjects is comparable tions greater than 300 million panicle? to th at for ordinary consumption 40 per cubic foot of air. years ago T h e prospects are far from 49. Also, Dr. Greentjurg reminds us{ that these is an important (actor o th e r' than the one of environment, which is that of individual susceptibility, in vestigators have noticed that men work hopeless. Silicosis is gradually being 46. According to A. E. Bussell, die ing in the same plant, at the same task brought under control. T he time is not disability rate among anthracite miners and in the same work place, frequently far distant when dangerous concentra from respiratory tuberculosis Is about do not develop silicosis to the same de tions of silica dust will no longer be per gree. It is possible for ooe worker to mitted in American industries. Periodic be an early victim, while the man work examinations o f those already employed ing beside him remains com pantivcly will detect new infections in persons frec. This angle of the problem indi now silicotic P rom pt institution of cates a need for further research. treatment will elim inate 'most of the hopeless cases of sllioo-tuberculosis. Preemployment exam inations will insure placement o f men in positions that they can fill without dam age to their health." 50. It is welt, nevertheless, to con sider all coal mining as involving a risk to some degree, depending upon the type of rock being drilled. White the hazard may not be as severe as in most metal Coal Wining 43. Anthraco-sniccsls is a term used mining operations, it b of importance at least because of the number of work men concerned. for a form of pneumoconiosis commonly called " miners* asthma.** According to Public H ealth B ulletin N o. 221, " Anthrmco-SHieons Am ong H ard Coal M in ers,** I t Is a chronic disease due to breathing a ir containing dust generated in the various processes involved in mining and preparing anthracite coal. I t 1$ characterized anatom ically by gen eralized fibrotic changes throughout both lungs an d w ith the presence of ex cessive am ounts o f carbonaceous and siliceous materials. 44. Symptoms found in early stages arc shortness of b reath, cough, pain in the chest, and possibly physical weak ness. In the advanced stages of the , disease there b loss of weight and de creased capacity for work, due pertly to pulmonary infection. 45. In studies conducted by the United States Public H ealth Service in Pennsylvania, no cases of anthracosilico h were found in the controlled group of hard coal m ining em ployees whose dust exposure averaged less than five million particles per cubic foot of air. However, the prevalence of an thraco-siticosis am ong the entire group of employees was found to be about 23 per cent. Among all except rock work ers, l o s than two per Cent Of the men were affected when the duration of en-' - ployment was less th an l S years, regard less of the amount of dust in the sir Among rock workers, who were exposed to dust averaging 35 per cent free silica 51. T he hazard of sOicosb seems to be practically absent in the manufacture o f cement. A recently completed survey of 2000 cement plant employees in all sections of the country by X>r. LeRoy U. Gardner and staff of the Saranac / " 4 # times the rate for general manufac Laboratory for the Study of Ttiberculo- x turing. The pneumonia rate is less than sU, has failed to demonstrate that the one-third of general manufacturing. inhalation of cement plant or quarry Bronchitis, however, is a rather common dust has a significant effect on the res com plain L piratory tract. Neither did it appear that men who had spent their Industrial 47. 5. L Cummins and S. F. Sladdenlives in sodi atmospheres were unusu conducted an examination of a large ally susceptible to respiratory infection. number of coal miners* lungs in South The incidence of influenza, disabling Wades. As a result, they made (he colds and pneumonia was not high- No statement---"Coal retained in large cases of rtintrat tuberculosis were dis amounts Only when there is a really high covered, and the incidence of healed or silica content-*' They added, " We be latent fod as revealed in the roentgeno lieve that in the absence of the silica grams is the same as that found in the factor, there would be, under modem general adult population; namely, 4.5 to mining conditions, no serious degree of 5 per cent. I>r. Gardner has stated-. anthracosis-" E. L. Collins and J. C. Gilchrist have claimed that workers who have had considerable exposure in trim "Alihou[h the examinations re veal no evidence o f respiratory injure from cement plant dust, even after in- ming coat ships where there is practi cally no silica exposure, but ncvcrtlwjltii. a very heavy dust condition, showed some fibrosis which, however, was not rtods o f tong exposure, maximum con* cent rations tn dusty areas should be re duced to 100 mittioa psrtkU i per cubic foot flight field count. itapit i f t r (ee)inique) as rapidly as economically feasi considered disablinc. 4.S. A study " f 2500 |Ktr-t-nirieni ble. High concentrations may not be dangerous, but they are not comiaiiM-' will, pood ItouscVtefhttc natflaril*. examination:* mark: in l'ii i.-burgh h<>>ptiab ihutvs thai city air which may "An exception lo the t i r r ,l ml- indicated by flic discovery o f tw o r m . , contain an unusually large amount of coal dust may cause lungs to become darkly pigmented -but yet produce no pathology oi importance other than per- of non-clinic! dust reaction in this \ group o f 2,000 persons. These men had been exposed to quarts dt /u s u ally in the form of sandstone) used in the m anufacture of special t m t t i 04/17/98 11:23 TX/RX NO.1994 P.014 HAROLD NIX & ASSOC ID :1-903-645-5228 APR 1 7 '99 9-26 No.003 P.15 -pply praciic&l m a n n ir ,' ktiowl^tlc^ *** * I NDUSTRIAL DUST M an^aficie: >0 mp. t*r cnt>< m tir i* (P rinter & HaicU) HIM' 7 6<S. O th er th r e sh o ld lim its for sp e cific d u fti have been staled as follows: A s b e s to s -- iD r t e iit n , ei al, U niinl S tates Ptihtic H tJtlli Service) ftvt m il lion particles per cu. it, # C o a l duct-- ( R. R. S i y t n , et at.) 50.- 000.000 p a rticles per cubic fo o l for coal dust con tain in g not over 5% quartz. 10,000.000 to 15.000,000 particles for dust w ith 1,1% q u a r t!, and 5.000,000 to 10.000.000 p articles fo r hard rock workers exposed to (lust containing 35% free silica. L ead---( L e g g e and D u ck crin g) m ore * than .5 m g. per cable m eter is hazar dous and (A . E. R ussell et a t), less than .15 m g. p er cubic meter it tale. Zinc oxide---(P . Drinker, el al.) 14 tug?, of ainc oxide per cubic meter for 8 hoars of exposure or 45 mgs. for short exposures. 69. Of the m etals, the following suggestions have been made: The Americai Public Health Associa tion Committee (ki Lead Poisoning stare m tlieir comprehensive 1043 Report that "whes* the air o f workrooms regularly contains more than 3_Smilligrams of lead to r 1A cvhid meters of 4ur. esses of dis abling lead ntnaitalim do not occur among men who work regularly in sorli workfpnm, an*! esses Of Questionable or tninor intoxication are rare. 1 practice the attempt is made to maintain the lead content of the sir within Such Ibnits a will >'ieM an average of not more than I-5 milligrams of lead per 10 cubic meters throughout iltc working day, while pre venting the occurrence of mttetially higher concernrations (S milligram* per Ifl cubic meiers or more)." Zinc Oxide: T o avoid metal fume fever the concentration should he kept below 14 mg. per cubic m eter for A hours* exposure or 48 mg. for short ex posures <P. Drinker et aL).i C ontrol of D ustiness 70. l*h ere are variou s w ay s in w hich dust diseases and annoyances m ay be avoided*: I. T he avoidance o f exposure frni*(ic~ t/ic rirst and most important ik i c m t against industrial disease. )!* Should he performed in clean a ir >< far as possible. It is not necessary, h o w cer. to prohibit all exposure to a toxic substance, ss the human sys tem can protect and cleanse itself to a certain degree. 2. Exposure can be limited by reduc ing working hours where dust con centration* cannot t* K d c n ily re duced to constitute an otherwise safe condition. 3. S afe processes may som etim es be substituted for those of an unsafe nature. An exam ple o f this Is th e substitution of abrasive' w heels made from synthetic abrasives co n taining no quartz, for w heels made from natural sandstone, which is about 95 per cent quartz. 4. The n b < ii.:tiu of wet methods for original dry m ethods has e x erted considerable control over dusty atmospheres. D ry drilling u the cause o f considerable dustiness in miam e, which m ay he greatly re duced by wet drilltsr. This is situ true in many construction and Quarry jobi. 5. An effective method for preventing the escape o f undesirable dust into the working atmosphere is the local exhaust hood. It should be placed close tn (he source of pollution he m ost e le c tiv e . T h e air should he discharged through a dust c o l lector to prevent contamination of neighboring areas or return of the dust through open windows Int" the plant, d. The routine recording of dusty c o n centrations is a valuable check on the existing exposure. Periodical counts of air sam ples are a great h elp in show ing w hether o f n ot there is need for further control. T. In som e cases, (he application o f general rather than local exh au n ventilation is desirable. There are instances where (he source of p o l luting materials is constantly Chang ing position and local exhaust b e com es difficult and im practicable Here a general ventilating system m ay be the only answ er, i ivutv Courtesy* Kirk fid 01um M hu(M tunn( Compiny Cl- K ahavst jstrrti fa*r KHiOvji t*f it-jii liuK ini iu m n . , *T h t etztlt (nethwls oi prevention rvh here qsnt<itqI'mhve4ClIxnrkih*lrdorDdretrvhIenr,"plndt)uIleintnMel tMJTe1d1i** 6'vUg OmfMuty*. N**4 tArfc. H. T. Figure i t ManufactKurfirnhg CUomBplaunrys Adjustable exhaust hoods (or polishing wheels. 6. A final-method of protection is the w earing of special protective equip m e n t by workers. T h is step is f r e quently the last resort and is used o n ly in an em ergency o r for jobs o f short duration, but- it is never th eless .( considerable Im portance. (S ee American Standard Safely C ede for the Protection of Heads, E ves and Respiratory Organ*.) 71. In many localities cades or or dinance for the central at dustiness are in effect which should be investigated and followed by employe seeking io improve working conditions. Local Exhaust Systems 71. Local exhaust ventilation (or the control of Industrial dusts and fume; coarist? of four principal .parts; X Exhaust hood* li. Piping or duct* c. Air cleaning plant <1. Source o f suction 73. White each of these parts should be designed and instailed to perform its required function with respect to the system as a whole, the exhaust booc probably demands the most careful de sign, inasmuch as the degree of control secured depends to i larger extent upon (be shape and location of the hood-- and the rate of air flow to it--than upon jny other single factor. 74. Hoods have to a considerable ex tent followed the design first e m p l o y e d in such industries as woodworking and metal grinding. Howes-er, a? noted b> Theodore Hatch, in recent years the in dustrial dust problem ha* assumed hy gienic and economic a.-Kti* entirely b*yvnri the limitations ui ihose indu-ir.cin whirh the (irtnUinir-n er riii-i-h*' been 04/17/98 11:23 TX/RX NO.1994 P.015 HfiROUD. NIX & flSSOC. . I D :1-903-645-5228 OPR 1 7 '98 9 :27 N o .003 P.16 P ' H . r i' - h e a l t h n c . u t j c /-;> j `. i M r t / u : r n o . a be told that the maintenance of cerim degrees o f air cleanliness represent? i bibest known practice. Moreover, h iu such stan d ard s would undoubtedly be o< value for a Single mdurCty,'under' riiftCT. ent conditions and in other induMriw there would be question of their appli. cabilfty. 65. A s the result of many years-,.! practical experience in dttet control in the South African old mines, a cone (ration o f one mg. o i dust per cubic m eter o f air was accepted as standard and 5. now known com m only a? "thr S o u th A frican standard." In 195-t. 1. 0 . Irvine stated that no miner who had H exed, the industry since th is low con centration had been maintained had. ay e t, contracted silicosis, type# <ii h \| r- e n siu v iiy . W hile thi> is p rohality o. according io D r. M ay R. Mayer.-, individuals do not become sen sitive Uf u b 'ia n c which later cause the trouble until they have had sufficient contact to l>ccvme sensitized. W hen a person who i ' hyper-sensitive first comes in comity; with th e substance, he is twit awart- hi- c-*n'li;i.n. An ''incubation perio-i > tluritnr which time repcate-i perhaps ,-ensitiic him to a i-).;.' '--re rubsetiocn cun: act: m ay rc-tr:' mnw-diAte ullcrgic reac tion 1h.- a u in g irfvio>l may vary from a week nr two to several months or even ;.r.-.r- Huwtvi-r. the allcriiic tender* \ h,'iu- tn-i-n in the intli- \"niii.i' '-< _-.n iih. :tii>l then thetv r n u - i 1 . i ' - I . . - i , l m u I u t i l I01 Cult- lac:- - o li- ta m c m cptc-^iion in orii< r :!-..r : iicnt aH. fc'n i c n i l t n r y C.m lie hi'-o--r.; n u t. i . o.-i -i i c h i i i i i i .1 i h . i t " r i c i ii 66. It was stated by 1). , Cum m ings In a paper presented at the Second Symposium on Silicosis at Sar anac Lake-- . . inform ation from field tunlirx m ade n m any part? of she w orld indi cated that a normal man m ight workin pure crystalline filin dti*t fo r many years w ithout impairing his health if the concentration did not exceed five m iltion particles per cubic foot of ait." 67. D r. h . U . Gardner states, con cerning the permissible dustiness where silica, is present: r-ultstancv. he m ay , more readily th a n iK'tiirr. Im u m c sonmi ivr- v lh ct sub- tancei. O ccasionally, t*.o, it has been suiCi^tcd certain individuals are callable c.t developing a Certain decree o f im munity as time goes on. However, from Che viewpoint o l prevention, it seem s (ogicai that wiirkingmen who have be- Cunic- allergic to certain .-ub.-uanccs in the c'lur-c iheir ..ccupaiinnc should be , * m * - i i r ; i j ( ' i ` ! " * i n i " " t h c r l i n o o l u./rk. :".*r t.-i m.*-i . a.-- - th,- 'cT.tltncy is l. . livi-mii :i.*m- v I'cpnurr -.in inuv- IVi nn->itvlc- Oci'-tit'c.vv t,~ c . :, i n 'll. i--c t.trl. ii:iiu f.<r <le* :nniiv r--.1- 1- (.rnU'-il) V liu-tnn.'*' I he f-.it: ii.i- *1 Ii<i-n ie,it hc'l It* tv :i ntanm. itiurt' c.m lie ii.ld the exact n>nccnitaii`*n- -i" huh. for ;n-tan*< . hi? men ..ill -t.it- 'It ' ehtpin* ra-e- -*f 'ilitif-is, as- - U. , :m nnlv "The evidence now available makes it seem improbable that a silica liarard is defined solely fey the num ber aoi) sic e W the silica particle* ir. industrial atmospheres. The other components o f a dust modify its action. Som e tn*y inhibit, others retard, and perhaps som e w ill be found to prevent its in jurious effect. Because these potsib.Uities are recognised, it becom es diffi cult to set op definite standards o f per m issib le d a u m e u ! industrial atm o s pheres. Dr. Gardner cootinues further: - N o t enough 9 known about the 5< (ion of protector substances to warrant the rcee*- -lendatio* that they be tm ployed to prevent 4*teosi* in industrOur aim should be to reduce existintd u st concentrations rather than to ir crease them by adding more dust, w ould very strongly oppose the rerun; m endation that protector dust be ir3i-` to attempt io pfevent silicosis at i>present time. But 1 fo believe tlu i u should attempt to discover m ore -si-'-i their action. Som e, like gypsum , sec to combine with silica in the atm ephere. forming clumps which are uh eavy to remain suspended in sir i t lOO large la pass the barriers ot <* nose and upper respiratory m e t * t ' 1'1 i- 1i in fo irr. .'ion at liatid. ii -us-' * 04/17/98 11:23 TX/RX NO.1994 P.016 MIX & ASSOC.. ID : 1 -9 0 3 - 6 4 5 - 5 2 2 8 APR 1 7 ' 98 9:27 No.003 P .17 IND USTRIAL DUST H .P .P .-i- -"Thi means, in effect, that dry frill ing can only be uicd with local ex haust* and adequate air cleaning. It happens, also, that wet drilling without ventilation wifi not achieve adequate air efeantinej* in the case of the high quart* or elaxi 2 rock." SO. T ie situ* Lion is well summedicp ia tua ed itorial th at appeared ia " Chem ical EagLneering u sd M ining Review" (M elbourne). "W hatever the ttltimate Endings at to the cause and development of pneu moconiosis, the task of the mining en gineer is indieated Clearly: the first es sential is to minimi** the formation of dull, and tbe second is to collect or remove unavoidable dust a* rapidly aa possible. Jn this latter respect, a logi cal forward step has been taken ia the adoption o f mean* to collect tbe d a at certain points of production in stead of relying, upon the general ventilation torrent to dilute and transport tbe in* jurious material. Smalt units are tow being Installed In some mines at load* ing stations and orepass tipplers, tbe installation and maintenance costs of which nr low and * high efficiency is developed. "M o re efficient rock drilling practice. *n reproved general standard of health, reduced w w king hours, provi sion of change house and other facili ties. and m any minor but im portant factors can also contribute to ** reduesinn in the in cid e n ce of siliC o ii ." ACKNOWLEDGMENT, This pamphlet was prepared b y W ar ren A- Cook, D ivision of industrial H y giene and Engineering Research, Zurich General Accident and Liability Insur ance Company, and reviewed b y F loyd A , Van A lia , Industrial H ygienist, N a tional S a fety Council. I t has been re viewed b y th e Safe Practices Conference C om m ittee, the H ealth Advisory C om m ittee, end' approved by the Executive Committee o f the N ational S afety Coun cil. In w riting this pamphlet, th e au thors have reviewed carefully the litera ture already m th e cld, and grateful acknowledgment is made to the num er ous publications. T he U nited Sta tes D tp a rttn cn t o f Labor has cemlribty: m a n y o f t h e illustrations u s e d her-. Appreciation is expressed also to Other! vrha reviewed and mb-miited getlions for the Im provem ent o} : work. Outstanding among those f ing the pamphlet thrir personal e lu tion are: W .T . Cameron, Untied S ic Departm ent of Labor; A. J. R ^ d r n . Portland Cement Association; Phil D rinker, Harvard U niversity; D r. L R oy U. Gardner, Saranac Laboratory /. th e Study o f Tuberculosis; Daniel lie ringiam. United States Bureau o f M ine: D r. M . 8 . Krtmenberg, Illinois Depar: m ent o f Public H ealth; D r. A . J . L oot. M etropolitan L ife Insurance Company D rJ Corey P. M cCord, C h y tlc r Corpi ration; D r. R . R . Sayers, United State Public H ealth Sendee; D r. C. D . Selby General M otors Corporation; R- C Stratton, Travelers Insurance C om pany, and D r. C. E . A. W inslow, Yale /n-; v e r tily . Rep, 04/17/98 11:23 TX/RX NO.1994 P.017