Document 6RVKZM7Yye5Y2mrRJxoy1vwMg

PLAINTIFF'S EXHIBIT tabbies' 86 Twenty-sixth National Safety Congress J, 5 have been associated wlthf geneHJ:!*yitcnuCi oils. The second type beco poisoning.* Dusts may be swallowed With of reaction is caused by toxic dusts like lead, asthf saliva, water, or food, and direct poisoning cadmium, and radium. A third type of mal- inch has been traced to absorption by this ady follows the.inhalation of finely divided method; other duits may act as irritants and metaKic fume piirticles sucK ai sine oxide, produce affections of.`the sld$ .irritate {mu-, ;and tls/^nwwnpasj metal fume fever, The com membranes |of hose, eyes and throat,' fourth reaction, - al(ergic in character, is often causing inflammatory diseases: of caused: by breathing organic dusts such as these organs.* [ ' pollen and eertain types of pulverised wood Some inorganic: dusts are able to pene trate the deep lung tissues and are sufficiently insoluble to be retained there. Some of these may be active in the human and flour. In! all four, cases'the sole.cause of thedisability maybe dust inhalation, but the reactions from toxic dtists. result from swallowing as well as from inhalation,1* - tissues, causing definite and permanent in For various reasons it. is difficult to set jury, while others are inert and may be up' an absolute classification for dusts. retained for years, apparently without seri Opinion is rapidly changing regarding stf- ous damage; some are gradually; absorbed called:inert or, handiest dusts and further without causing pathological changes.' investigation may prove some of them to be All inhaled particles are soluble, at least to a small extent. If harmless, cell activity is stimulated so that phagocytes remove the dust If the solute is toxics die viability of the phagocyte is affected and an Ineffective accumulation results. At the same time, further solutemay diffuse into neighboring tissues, setting up . an . irritation aha subse tajuriousi '`Some. :dusts may have both a toxic and.,an.irritant..actionwhile on the other hand, the poisoning resulting from ex posure to a dust may be the combined effedt of more than one mode of. entrance into the. body. However, the following classification ' of dusts,--, according to physical character istics and physblogical effect, is used for quent, fibrosis. The nature as well as the convenience.-' solubility of.the|soliite is an important fac tor, but of two substances of approximately I. Organic Dusts equal toxicity, ; the more soluble' form Organic dusts are . those which contain - causes the greater damage. However, sub-' carbon,* and were originally supposed to stances, of such low solubility as silica may , come from organised'[isubstances derived . ultimately produce extensive injury.4 from animal or-`plant life. Living dusts Kettle has stated that harmful dusts, if come, under this classification; and are inhaled into thejlungs; may activate a latent thought to be. of the same order of size as tuberculous infection; they may exaggerate industrial dusts, with ,which they _arefre-' an active tuberculous lesion or a coincident quently associated. Bacteria are usually be-' infection. If sufficient quantities of Charm less dust are inhaled, some of it remains in tween Oi and 3 microtis, except. & a few cases, such as the anthrax bacillus,:.which l , . the lungs and causes a'mild degree of fibre- r- ranges from l.to" 125..micron in breadth, sis merely through mechanical irritation, and 4.5. to 10; microns in length and 10 or 12 but such fibrosis is never sufficient to inter microns in diameter. However, it.is possi fere with the function of the lung.* j ble, that the larger and .heavier varieties, Some writers! state that while the influ like the: larger and heavier dust particles, ence of nonpoisohous dusts on health is a debatable subject, abnormally high death settle due to gravity, and do not remain suspended in the air, rates from bronchitis and pneumonia are . Many thousands of organic substances, sometimes attributed to chronic exposure to carbon-containing, are made synthetically nontoxic dusts. Large amounts of dust are by chemical processes, such as dyestuffs, occasionally found in supposedly normal explosives, etc. . , lungs, at autopsy.* l. Nonliving organic dusts, as According to Drinker, there are four dif the name implies, these are comprised'.of ferent types of reaction produced in man by nonviable particles, which may or m^y hot the inhalation of dust The first and most be inherently1, toxic of irritant,: but which important are the pneumoconioses, such as nevertheless produce untoward effects in the silicosis and asbestosis, which cause specific human organism;;' "Allergic" dusts, or those lung pathology and often are followed by to which only certain persons are . or may Industrial Dusts 87 become.; hynperienilUv^f^ dust, orpowderformofthepreparation,ex- j\ithm, rhlnltli'i or4:bto&-disturbances, are ertlnga direct irritatlngeffectontbeildn.'f includedinthis Classification! ^ . ' Dermatitii>.due-;!to^ "di T6jdrani'/Si^0^Ml'Tpx\tor, irritant such as vanilla, powdered arnica, pyre- - dusts are all di!^^`tfuitiVwhich::jproduce throng etc.,1 have been reported# . . . . .untowaitf' ' DentBl leilons, ' Of ocnipational origin, local.-^Thdle ^IdcmlJnrmptoma are have-been reportedamong workers in sugar. usually deicrioed ii' Irritant } those produc- The glngivitJi cauiedsbyjSUgar duit is clas ing, general'"for? systemic1 symptoms are sified as 'purely mechanical* with later- termed toxic. A dust may be both'toxic and developing/toriei..-.> Dilutive : disorders, Irritant,' respiratory 'conditions, find icutaneous con In reported cases of Injury or death fol ditions'(especially of- the' face) were alio lowing inhalation of dust'from organic corn- found,111 pounds,/among the chief offenders are Dock . workers, transporters of grain, paranitranllme, the dlnltrobensenes, chloro- workers in grain and 'flour mills, etc, are dlnttrobehienesl k,trlh!trbphehb],/ and nitre- exposed'to dusts durlng thelr work. Dusts nftphthalene." Eye! damage due to Inflamma from cereals- may contain iiiiany, impurities, tion of the cornea has occurred among which may 'cause an irritatlngactionon the workers exposed to; inethyl violet diut. The . respinrtbry paisiagei^as' weir as inflamma dust from parapKenylene diamine derivatives tion of toe skin, Digestive disturbances, Is particularly irritating and dangerous, dental defects, diminution.ih hearing, and causing not.only a seyere. form, of derma conjunctivitis: have, been-observed among titis where /the dust .combi; in contact with millers, and have been attributed to toe dusts the skin, but also producing acute inflamma to which such wprlmrsvare exposed," tion . of . the. mucous membrane of the b. Alltrgic.i Many/.apparently innocuous respiratory passages!4 Toxlc .dusts may be substances . may. produce reactions in per- - generated during. the handling of powdered, sons.of peculiar personal; susceptibility. .The , dyes mid in preliminary dyeing operations,' " term "allergy* - is used to describe this;con- i particularly . the; hydro^tractor -process, dltion of hypersensitiveness or susceptibiiity, where particles are disseminated in all di- and allergic phenomena^ most. frequently rections.M: Coal tsir andindigo dyes are manifest themselves in:skin reactions.. How ubstances most frequently used.' ever, they may cause acute reactions else Cases of amblyopia, have been reported where in the body. . When the'respiratory from, exposure to . inhalation of tobacco tract is involved we have such well known dust." It has been found .that inhaled to . diseases as, hay, fever or asthma. These bacco dust exerts' a hipotine action on the diseases may develop as a result, of hyper organism fifteen times "greater ` than that sensitiveness tojsuch substances as i pollens produced. by: the: same /quantity of Smoked from plants, horsehair,, rabbit's` fur, furs, tobacco with an equal nicotine content.1* feathers, etc.' , Severe'dermatitis is experienced by many workers handjingpowder containing TJt.T., which is used ;in making high``explosives. Picric acid, which is also used for this pur pose, requires drying, and in this latter state has been found to produce a. dermatitis. Picric add i* also the; oldest synthetic or ganic* dyestuff.14 Dermatitis occurs' among handlers of silk ,with .varying frequency. Sails ' determined .that a rash occurring among workers in asilk factory was due to For instance, furriers, workers in clothing industries who. are exposed to wooldust, etc., may suffer from hay. fever or asthma^* It is unnecessary for. the bffendiflgv.diist.to. reach toe depths' 6f the lungs--giant pollens for example are reported;to produce-their effect after being caught .in, the: upper- res piratory passages. -Should suchan.offending substance be finely ground it could:,reach the alveoli aud its a result probably all physiologic reactions would be accelerated.1* dust from silk cocoons imported from In a survey of a piantwhere resin.is Africa"- -. mixed, ground, and. molded,.1 it; was found / Persons `engaged in the manufacture of that 80 per,cent.of the occupational,derma quinine and quininepreparations suffer from titis . there: was/due .to hypersensitivity.: to sldn phenomena,- whidr occur for the: most hexamethylenetetramine and formaldehyde part on .exposed parts of the body, and contained in the dust, to which the workers may be caused by ingestion or by quinine were-exposed.11 During the first processes 88 Tiventy-sixtk National Safety Congress of cotton spinning; cotton-strippers are ex trichum derxnatodes),;.which isescattered. posed to dtist arising from cotton husks and when the bark is stripped off.,This powder: d&ris, which produces a typical form of is irritating to the1 skin, and mucous mem- . asthma.* branes. Mycelia and spoi. of moulds are Ordinary wood dust has been of interest commonly - found toj;cause, rashes:, for in- due to its purely mechanical action, but staace/'/.tbe. black. powder.; coming, from still greater care is required in handling macerated sugarcane steiks.' Among basket- - certain kinds, especially woods coming from makers, the' mycejUum(aiid;"; spores., in the abroad, because of the-essential oils impreg form of a wl^e mquld (hOTbpm^t^ from . . . nating them, which when freed in the dost the rhattan canesused,get.shakai,outwhen may affect the health of the workers con- , the - canes are split: hammered, and; cut, ' cerned. Some of the woods' capable of causing painful fissures to develop oh the causing skin lesions are Brazil wood, satin- skin wheretheyalight** . wood, teakwood, cumaru or tonka, wood, A form,of asthma or ..spasmodic cough, black ebony wood. West Indian mahogany, suffered by .'cottom Weavers/ahd known as Japanese tagayasan, coccoloba, chestnutwood, aspergillosis, hasbeeri considered due. to in-- - olivewood, California sequoia, etc. All per halationVof spores of a. mildew.Whichsome- - sons who handle these woods are. not in times';occurs,on "thethreads.** .Iti a study jured, only those particularly .susceptible .to. of sycosis, among -miners, made, % the the substances they contain becoming Public Health Service, a nutnber of ` cases, affected.** of typical limliaiy calcification .were, .en 2. LIVING ORGANIC DUSTS. These contain particles capable of exhibiting the phenomena of life* (especially the property of reproduction or multiplication), such as bacteria and fungi. They are usually found in low concentrations and are associated with nonliving dusts in the air. countered. Unstained smears of those cases - exanuned were; positive for' fungus, two types of Aspergillus fungi being identified.- . All of- the subjects, but one were ^farmers, teamsters, feedmill workers, or residents of . small agricultural; "towns where grain is marketed. Fanners are. exposed to fungi in threshing wheat,' baling hay, or' .handling- a. Bacteria. One of the most important' various small grams.1* among these is the anthrax bacillus, which Some other fungus diseases such as actino is contained in the dust from skins, furs, mycosis and ..blastomycosis are associated- wool, and animal hair, horns, hoofs, bones, with occupational exposure tb--dirit. The etc. This disease may occur in two forms: former occurs among workers handling cutaneous, (in which the organism affects straw, hay, grass; vegetable dlbris contami the skin), and Pulmonary (when it is inhaled, nated with mould,, etc.- 'Actinomycosis', is as in tize form of anthrax known as wool- likely to affect people engaged in. commercial . sorters' disease).** handling, storing, and; cleansing of. grain Cases of tetanus, reported in connection with jute manufacture, were traced to the raw material, the.bacillus havingbeen found in the factory dust** Diphtheria, tubercu (grain distilleries, .flour mills,`grain crush ing, breweries, and malting houses,/ etc.)." - \ ;i II. Inorganic Dusts ; losis, smallpox, typhoid, or other bacillus- Inorganic compounds are of mineral produced diseases, may result from exposure 1 origin, not requiring a living organism to , to infected dusts. produce them.** A number of-dusts not Bacterial sensitization can be the cause of . usually classed ,as toxic may,..under, some- - any of the allergic diseases, namely, asthma, conditions, produce untoward^ effects -on the perennial, hay fever, urticaria, angioneurotic human organism. Classified mder- ihorganic edema, eczema, or migraine headaches.** are toxic and/or irritant,. fibrbsis-prpduc- ' b. Fungi. Dusts containing the. mycelia ing, and. nonfibrosis-producing dusts, and spores of parasitic fungi give rise to a. Toxic and/or Irritant. - Toxic dusts ar^ annoyance and discomfort "Maltster's" itch . those which are inherently toxic when in - from the dust alone has been reported. Iti haled, ingested,1.. Or- otherwise, absorbed. Provence, reeds used for ceilings are stacked Among those whichproduce systemic, poi while still wet and undergo fermentation; soning, some of which'are also irritant, are they become covered with a white*powder the dusts'from heavy metals and their salts, (a dry fungus of the Mucor family: Sporo- . such as lead; mercury, arsenic, cadmium,  Industrial Dusts 89 zinc, etc Irritant .dusts-are injurious .by cer are reported to have been caused by jeaSorirO&iheir strong irritative or corro exposure, to. dust of arsenic. compounds. sive properties.. Certain aluminum saltsare. skin irritants As a-rule, inhaled irritant substances im and aluminum dusts may contribute to the mediately 'cause a reaction-in' the upper - infection, of skin -and. mucous membranes, respiratory tract of, such: severity that; they through mechanical ,action.* - * are prevented from'' reaching,the lungs, - al . b. Fibrosii-Producittg Dust's. The most though- they;, may' cause lung damage * by important of these are the inorganic, slightly extension of-inflammation if the. mucous, soluble dusts which, cause -fibrous changes membrane is corroded,*; Lime, calcium oxide, in the lung: tissues, some of which are seriand the di-chromates- areexamples of irri > ous, and some: oLwhich cause, little or no tant dusts. An- inorganic: dust may possess, disability.! So far as 'is known, no indrganic both - toxic and irritant .properties, and. the substances other than silicon derivatives poisoning, produced : may be the combined cause rnore.thah a very moderatetiegree of effect of more than one mode of entrance fibrosis of the lung. . Moreover, there seems into the body. to be no-evidence that any other constituent Of- the directly, poisonous dusts, the most of ordinary dusts can influence so unfavora widely prevalent are-'those of-certain lead bly a pulmonary infection.*. compounds, particularly die oxide carbon ate and the chromate. The dust is .readily absorbed by the mucous. membrane ; some dust passes into the stomach and is dissolved by the gastric juice*. Although other-:dusts,'when inhaled in sufficient' concentrations over-1a long period of -time,- have^been--shown- capable-of'pro" during a pulmonary' fibrosis, nevertheless, the: pneumoconiosis characterized by. nodu According to Fairhall, perforated nasal. lar fibrosis, has. to date been shown clini septum is a common occurrence among cally and experimentally to be associated workers with bbchroinate dusts.* In a only with the inhalation of dusts containing study. made by .the U. - S. Public Health free silica. Service it was found that continuous daily Since this dust; to exert its. harmful action, exposure to concentrations ofchromicacid . must enter the finer divisions of the lung, mist greater than 1 milligram in 10 cubic the-particle size, of the atmospheric dust meters is likely: to cause definite injury to.: may bear a definite, relationship to the in the 'nasal ..t&sttes* tIt' is -believed that a jurious effect produced. The silica must be Similar concentration of the dust would be present in the air in particles small enough dually toxic. to enter the finer - air'-spaces and. of .such " In tire-case of poisoning from some heavy dimensions that; the: phagocytic ceils 'may metals, exposure may be to both dust and engulf them. ` The greater majority of parvapor. For - instance,' investigations have " tides found upon microscopic examination :ysliown the safe, limit of-, total exposure to of the lung fall within the limits of from dead oxide dost and-- fumes to be less than 1 to 3 micr&ns,* lucamples of siliceous dusts 15 mg. per 10 cubic, meters of air, except are granite; quartz,' sand, pumice; slate, etc. for prolonged .exposure.* In exposure to In a recent study among anthracite miners, mercury, dust and: .vapor, it was shown that the correlations between exposure, to dust the incidence; of .chronic mercurialism in- (which contained silica) and the evidence . creases rapidly with increasing mercury of constitutional changes, left little doubt concentration, ?ftersuchconcentrationx- . as to the etiological significance of the dust ceeds 2.0 mg. per lOcubic meters." ` in the air breathed. Like correlations were Alkalis and metallic oxides are common found between the. silica exposure and -the causes of dermatoses. Lye,; potash and extent of pulmonary changes*.. When-the lime are known-to cause irritation to plas inhaled dust.-consists, of.-silicacombined terers, cement-makers, bricklayers, masons, with bases, silicates, some degree of change stonecutters, modellers, and metal platers* in the pulmonary tissue may result. In this Ulceration and perforation of the nasal sep respect asbestos dust seems to. be unique tum occur among workers' exposed to the among silicates in the, prevalence and se * dust of soda ash; systemic poisoning1 also verity of the disease it causes," occurs from inhalation of calcium cyanimide Tbe chief distinction, between silicosis and dust." conditions due to simple reactions caused Cases of . dermatitis, scleroderma and can by other dusts is the active proliferative IndustrialDust#. 91 gloves, goggles,and.aprons; as well as pro of disease." Since some occupational dis- tective salves;; ointments, or other com eases tend to dear up and recur, records of pounds to ..delay or. ditninish the' irritant previous occupations should, be included in action. General rides for hygiene and good the physical examinations.. The, frequency housekeeping should also, be observed. of examinations: should .be determined by Medical Control. Equally important, and closely interrelated -with the; engineering, phase, is medical control of (occupational hazards. In addition to directing the proper the medical.director,, unless otherwise speci fied by law.\Those.fexposed'toknown occu pational disease hazards inay have weekly or monthly examinations.'* ' . placement of new workers, and guarding the "It should always be kept in mind that the health .'of,all employees, medical control is basic principle of physical examinations in . a check on the efficacy of the engineering industry is to keep men on the job and not ' Control - methods already instituted, or a allow the physical examination to be merely measure of the need for new protective de a weeding out process.' vices. It has been stated that "Industry has References found that the best way to. treat industrial ' Bloomfield, J. J. and DallaValle, J. M. "The injuries and illness is to prevent them,' Determination and Control of Industrial Dust." U. and medical control, through preemploy S. Public Health Bulletin No. 217, April, 1935. J* Collis,.Edgar Li "Industrial Pneumoconioses, ment and periodic physical examinations, is with special reference to .Dust Phthisis." Milroy one of the most important factors in such . Lectures, 1915. JH. M.S.O.: London. * Sollmann, Torald. ."A Manual of Pharma prevention. cology. W. B. Saunders & Co., Philadelphia, 1932.: The preemployment examination is made. ` Fairhall, - Lawrence T. "Toxic. Dusts and Fumes." Journal: of . Industrial-Hygiene and Tom* to determine the employee's physical and -mental fitness for work. It serves to dis and Analysis ---------------------------- ---------------------- s Health Asso close the presence of any contagious dis ease, reveals any; minor physical defects ciation, Yearbook 1935*36. `.Gibbs, W. E./`Duat Hazard in Industry." Ernest Benn, Ltd. London, 1925.' which might,later become serious, or whether the examinee's condition predudes . Ins em ' Air Hygiene'Foundation of America, Inc. "Silt* cosis and Allied Disorders." Medical Series, BtUle. tin No. 1. Pittsburgh, Pa. April 15.1936. ployment in certain or in all types of work. It should be remembered that such preein- * Kettle, E. BL "We" Action of Harmful Dusts." '1In93s4t,. of M; ining and Metallurgy, Londo* n, June 14, ployment examinations are not to be made .for the purpose of eliminating ah employee, "Dusts, Fumes, and Smokes." Occupation and Health Series, International Labour Office,.Geneva, 1930. . J. -but rather for allocatmg.him to the .type of work for which he is physically suited.' A '`Drinker, Philip. ^Causation of Pneumoconi osis." Journal of - Industrial Hygiene and Toxicology, .October, 1936. worker should be given employment' unless totally unfit; or unless his disability, even - '''`Dyeing." Occupation and Health Series, International Labour Office, Geneva, 1930. ' ''Legge* Sir. Thomas. "Industrial Maladies." though slight, would cause him to be a haz ard to himself or his assodates. Further Oxford University Press, London, 1934: Burstein, A. ."Nicotine Action from Inhaled Tobacco Dust". Journal of Industrial Hygiene, De more, the practice of preeinployment examinations should be. extended to indude cember, 1927. ` _ '* White, R. Prosser. `The-Dermatergoses, or Occupational Affections of the Sian." H. K. Lewis executives and officials of industrial organi zations. . & Co. Ltd., London, 1934. " Schwartz, Louis. "Sion Hazards in American Industry.". U. S. Public Health Bulletin!No. 215, "The. purpose of periodic physical October, 1934.. " Downing,-J. G. "Industrial Dermatoses: Treat examinations is to secure and maintain ment and Legal Aspects: Review of Recent Litera physical fitness and thereby lengthen work ture." Journal of Industrial Hygiene - and ' Toxicology, July, 1935. . spans.' Reexamination of employees some- . *' "Occupational Lesions in Workers in Sugar." times results in. the discovery of defects and disabilities which were hot observed at the r---- _ time, of .employment In such cases,, ah oc _ "Flour Mills. Occupation and Health Series, International-Labour Office,.Geneva, 1930. . cupational adjustment should be^made to " Mayers, May R. "Susceptibility to Dermatitis.". provide continued employment bjsfc remove ' The Industrial Bulletin, Albany,-N. Y. voj, 16, no. 2._- : Feb. 1937,. the risk of permanent injury. "Drinker, Philip, and Hatch, Theodore. "Indus, trial Duet.1' McGraw-Hill' Book Company,-, foe., Reexamination' of employees is required New York, 1936. by law in certain occupations in which the _ * Schwarts,' Louis, "Skin Haxards in American Industry. Fart II," ; U. S. Public Health Bulletin. handling of poisonous or otherwise deleter!- No. 229, Sept. 1936. . ous substances may result in the contraction "Poisonous, Woods." Occupation and Health . Series, International Labour Office, Geneva, 1930. . ( rV ` i Mi. m *3*S> . - : ...'.. :;;. ;_. " ; .. .\ V' . ,, Industry.. i^American;. imwiTiriTTi i. v! * TV;rSr : ;. Newr .v,*--tv.: * . ________ ______________ r_______ ,___ ; -.v;,--5- . -------------------------- .-;V;.ir,= -., .' -. / < * i'V k^tfiaMis^iind. treatment/iBy^ehtifiOtreatment^ jwif/v^Si^SS,____ todhricM :aiadty)ib&.^]iMVlm8i^3b*'^Bseai^ controWIa^^ln^e i^dbWf j^|d^ddthini*.; Istfativel are&pitaif Itura^i'ci^ldenble^tiee.'.'' njawgaw' and: whlch .wTll admit of most treTahtmategnotes for ibmemdeirdeiactteedaandtc-aecuosneosmitbicaa{tl /han. dlin.g>., the dust hazard in an wlj. and*'^ a given plant It goesdouble for acquiring seibuin knowledge to " * `* ` " * '* looiely put together and liir^sly' emplrictd. ^ There are estimatesonly to jt^' tte-mag- nitude of die dusthealth problem, and it it so doiely Msodatedwithotiierhealthproblomi that a clean-cuteitimateof it alone i* im* poV.lbler We do know that 'it'irgmt in 'the _______ yardsUc nt^!to^^K^d:(iM[ibqtth i^ w^ti^^^of'diut^e eritire aggregate, and. fpir theindividualplant it.may . ,be very bothersome-and expensive. What actually- makes quark dust cause I dohot*mera one'per r-. .!'. silicosis is hot known. Itdoes/so the air Job breathed by workmen must hot' contain harm- are 'mapy< ful quantities of respitfeble quart* dost Inex- figured atallliut'g^ re- *< neer seVVeI .-n\.-; cam SCOf anio Indt co* Mat the' invc this the -^^^MBmMmmvmSmBbmmSBHBKkr-:- ': 94 Twenty-sixth National Safety Congress . below five million particles. They seem will* trical phenomena which bear upoit dust be ing to graduate upward to 20 million lor havior. ; medium silica ami 50 million lor low silica Those are all principles of physics which percentages. Five million particles is virtually explain the behavior of dust- and upon which dust free, and is very difficult and expensive engineering practice must be rased. They to achieve and maintain. The .declaration of must be understood and be taken into account. safety ol the installations must remain in the Dust control is not i matter only ol general hands of the medical and hygiene groups in ventilation; the engineermust;study the pro whose hands now lies the responsibility for duction as well as the dispersion.' The problem determining the hazard.. should be analyzed to determine the applica- We now enter the chapter of our discussion bility of segregation, enclosure, wetting, local Intended to demonstrate that dust control is exhaust and general ventilation. . an engineering job, that it must be given In some instances, substitution ,ol non-haz- scentific treatment, not guess work, applying ardous material,'or hoh-dustrprpdudng oper engineering methods which are based upon a ations may have spedficappticatibn, and they., knowledge of physical law* the behavior of should be explored first This implies plah dust, the performance of air-moving machin . engineering. I am .convinced that many bad . ery, etc. installations are bad because plant engineering , Prerequisite Knowledge ' was not used. In the designing of exhaust systems installed to capture the dust.at. the . points of generation, the physical behavior of Let me recite briefly, a few of the things which, in my opinion, the engineer should air proving toward hoods and in ducts must be known; and that knowledge used. Each know to do -tins job correctly. . He must know how to make a survey. Surveys depend upon sampling, and sampling is . not a catdi-as- system must consist of collection hoods, pip ing, air-cleaning plant and a source of suction. Before selecting a hood for a job the engineer . catch-can proposition. It - involves the place, I must know dust dispersion by dynamic pro- - the time, the frequency, the amount in a sam ple, and the number of samples so that nuudmam, minimum and average data mean some-' jection as well as dost dispersion by air ciir? rents, and design the hood accordingly. ' tiling, so that credibility can be given them. Knowledge Needed For the type of sample involved he must know how to weigh or count respirable dust, The aerodynamic characteristics of suction as distinguished from large masses of non- hoods appear to be tittle knowmbecause little resptrable dust which complicate the picture. . thought was . given to them in designing He must know how to observe the sources of . thousands of hoods which can be found every- ,- dust floods as distinguished from conditions where' in industry. All the possibility for " of normal dustiness. He must know the entrapping dust and much of the efficiency of sources of dust and the principles - involved the system ties,in this factor. Air velocity,, in the dispersion of dust. He must determine static suction, and rate of air. flow are all how much dust enters the problem because it related, and they must be known. It is essen- is:part of'the material, and what dust is tial to use high velocity of air in certain types created in the process by the fracturing of the; of exhaust systems to entrap dust projected material. . at high velocities as in . the case of a granite Any. less survey cannot tell the engineer what his task of dust control is. To visualize that task intelligently he should know the physics of Brownian motion, laws of resist surfacing machine, and low velocities must be used in others, .as in the case of cleaning, asbestos fibre of dust to prevent wasting material. ance to the motion of particles moving in air, Quantity of air and its.velocity must be. both when the air is in turbulence and for determined, then the piping should be de stream-line motion. He should know terminal signed to take into account the behavior of velocities, movements due to centrifugal mo air-flow through pipes at low,and high veloc tion ; flocculation and the effects of air motion ities. Where' the problem is complicated by and the effects of humidification on it He the large sized particles which-go along with must know all about the difficulties of wetting the fine dust, how these behave must-be taken - and what is known about overcoming these into account Pressure losses are.very impor difficulties. He should know the several elec tant elements in - the .design of an exhaust Industrial Dusts 95 system. Lois; at the; hoods, loss at the bends, tions must .be known, atid used. Performance |ndJoss In the duct* ,muit not be gtiesied at. cannot be left to guesi work. Supplying suffi Pipe design must take into account the gage cient air to be.exhausted is part of the prob- of the metal and reinforcing to withstand lem. The same may be said, of heating. pressures and eroiiion... . I The setection of a fan and its motive power is a matter of calculation, not guess work. Do I give the problem too severe a build* up ? I think not. Rbmember these two things: Power consumption in the lyitenr is. calculi* ble, fans follow certain- laws, so the engineer must know thebehavior of axiat flow, pro* peller type, radial -flow, paddle wheel and other fan performance. . More physics and engineering calculation goes- into the air-cleaning apparatus. The selection 'of gravitation, inertial or -filtration method depends'upon what the dust is; the calculation for-any. methods requires knowl edge of discharge'through stacks, the deter mination of sizes, of settling chambers; die 1. You are dealing .with hazardous mate* rial so small in sjze and so little of it by weight that it is. as invisible as die air that bears it. 2. Physical laws involved in the behavior of dust and air do hot. permit inexpensive methods of control. I am acquainted with budgetsset up for'this purpose which amount to more.than a quarter of. a'million dollars, , and I know of many where) to 80 thousand dollars is involved. behavior of cyclones. The use or non-use of . a filter, and if so, what type, how it should perform, how big' it should be, what kind of resistance ahd..how much each kind offers, to say. nothing of .their., proper location with relation to cleaning, accessibility, etc, are all items for accurate engineering determination, The need forjthis much engineering is rec ognized by then who know. Already muchhas been done toward getting the'-knowledge into handbook 'shape1 Perhaps the. best, job of this, sort to date is "Fundamentals-Relating to' the' Design and Operation of ' Exhaust Systems'' developed under'American Stand Apparatus.to check the behayior of installa ards Association procedure The Doctor's Part in Controlling Dust Hazards By A. D. LA2ENBY, M.D., F.A.C.S. Chief Surgeon, Maryland Casualty Co., Baltimore, Maryland Considerable confusion has existed in the recognize the disease when it is fully de past as to just what is the physician's func veloped. tion in the'prevention of dust, diseases; and It is not necessarily the physician's .func- just whptis the engineer's. It .is very ob . tion to analyze dust That.is a task for the' vious upon even casual thought , that the chemist and the petrographer. It.is not.the two sciences must work .hand , in hand in physician's function to count the particles of their efforts tosolve the problem.' . dust in a given industrial -atmosphere. That, The physician through his special training in reality, is. the function of. the engineer. It must be able to tell.the engineer what dusts ' is not the physician's function to devise are dangerous, and what are hot He must ventilating equipment for the removal of know how those, dusts enter, the-body'and dust; nor even to be more than an adviser the manner in which they do their harm. He as to the means that most- be adopted to must be trained in the examination of per . render the atmosphere safe; sons.. who. are . tp be. employed to work in The physician nevertheless must correlate dust, and to discover those who are. already with his medical, knowledge and'with his diseased, or. are peculiarly susceptible to studies of the ihdus.tnal.wbrker the findings dust disease.. He must be able to detect the . of the engineer. A diagnosis of silicosis, for first signs, pf disease, in workers, whp are example, requires not merely characteristic exposed to dust, and must be prepared tp - occupational history and characteristic physi- \ ! I i i 96 Twenty-sixth National Safety Congress cal findings, but-the knowledge as well that We -liave-lno real knowledge as to true the patient has been exposed to hazardous figures; :but as a simple ^rute/ vie can adopt dusts in dangerous concentrations.' . . for practical purposps/thethought that >the All dusts when inhaled in excessive. quantities1may be considered as harmful, but only a few can be. regarded, as dangerous. From the standpoint of their dangerous properties, they may be divided into three general groups. 1. Those which are dangerous because of their poisonous action, such as lead, arsenic; mercury, and similar substances. human body can withstand1 successfully' a concentration of dust containing100 per cent silica .dioxide inaparticulate- size: less than 10 microns, in a concentration not ini. excess of 5,OOOiOOQ-partides. per,cubic: foot If we decrease. .the, percentage: - of. silica- .dioxide present in thie dust,-.we can correspondingly increase the .concentration with comparative safety. We must, of . course, take intp ac count the portion of the worker's time spait 2. Those which cause only irritation in the in the dusty atmosphere, ' respiratory] tract, resulting in such condi tions as bronchitis or local inflammation; such substances as vegetable fibre, cork dust, flour, starch, and other relatively innocuous organic or inorganic materials. To arrive at a.rough conception of a safe atmosphere; we multiply the percentage -of free ailicain a given dust bythe total num ber of particles per cubic foot. If the result is under 5,000,000. the condition may be .con 3. Those which tend to produce fibrosis sidered relatively safe. If the result is over of the lungs, thereby predisposing to respira 5,000,000 the .condition must be regarded .as tory infections, especially tuberculosis, such unsafe. - ; * . dusts as asbestos, sjlica dioxide or mag Hear in mind too that silicosis is essentially nesium silicate. a disease of great- chronidty. Except in a I shall confine my remarks chiefly to few exception^: instances it will require dusts occurring in the latter category. from seven to . thirty-years for-a worker to It has been generally believed that the harmful effects of dusts inhaled into the lungs depended more upon their physical structure than upon their chemical. It was believed, for example, that ptiica'dioxide, or quartz, was particularly harmful because of its crystalline structure; and the hardness and sharpness of its particles. This concep tion is how known to-be faulty. The dusts develop advanced silicosis. If is evident too that coincident dusts may either retard the development of silicosis dr hasten it. Recent research seems to .indicate that the admix ture of aluminum dust to a aiticious dust will greatly inhibit the reaction of the latter; whereas a.silidous dust combined with some a!kalinercdihcident'dusts may hasten the de velopment of. silicosis. which cause their damage by mechanical in Much research is now under way in prob terference with function are the dusts which lems such as this. We have never learned how are relatively innocuous, whose symptoms are transitory, and which subside upon re moval from exposure to the dust Chemical Effect Is Harmful to cure silicosis, but we are learning rapidly how to prevent it Our knowledge In this respect seems to be limited-to the removal of dust from the'breathing zone of the worker. Later discoveries may show us how' to The disease of particular: interest to us modify existing dusts with contaminant today, silicosis, owes its harmful effects very dusts that will render silica dioxide innocu largely to a harmful chemical reaction oc ous. .. curring between silica dioxide and the body tissues. It so happens that silica dioxide is decidedly a tissue irritant to the body, re gardless of the part- of the body it invades, it causes local irritation, local destruction of tissue, and the replacement of that.tissue by scars. Owing to its very great chronidty, it is only the rare case who actually develops disabling silicosis during his industrial life time. It is realized, of course, that excep tional instances take place, but the coinddent ravages of ftge usually keep pBce with the effects of dust, so that much nt the dis-. Thus, given a dust containing silica diox ability usttaljly attributed to silicosis is often, ide in sufficient concentration, in sizes small in fact, actually attributable to. other1 dis enough to permit its entrance to the ultimate eases or incaparities which advandng'years air spaces in the lungs, we have a situation bring in their wake. To me the great peril of which offers danger to the worker. silicosis, the peril not only to the industrial Industrial Dusts 97 worker'ljjimself, but his family, co-workers silica dioxide is very likely to excite into and-the public .generally,-is the accompany activity a turberculous lesion which may be ing susceptibility to tuberculosis. 1 Complicated by Tuberculosis - quiescent or arrested, and once such a lesion. is reactivated, -the chances Of recovery are remote. Silicosis per se does not lull. Tuberculosis The second problem which confronts the as a complicating factor of silicosis rarely physicianaf the pre-employment physical ex recovers, despite treatment, and the indi amination is whether a given individual is, vidual so afflicted is not only totally dis by reason of secondary physical defects, abled himself, but a definite menace to all more susceptible to the development of sili . with whom he comes in'contact, particularly cosis than a normal. Is he suffering from the fellow worker who may have silicosis. diseases of the nose or upper., respiratory So perhaps die most important places in tract, such as chronic sinusitis, disease of the which the services of die physician in a dusty lungs or. air passages, or obstructions which trade are necessary are--first, along lines of produce mouth breathing? discovering and barring from exposure to We must remember that silica dioxide is a silicipus .dust those persons who may al not dangerous until it reaches the lungs, and ready have arrested tuberculosis; and sec that the - normal individual retains in the ondly, discovering those persons already ex nose and the upper air passages a large posed to dust, possibly already silicotic^ in quantity of the dust Inhaled from the atmos whom tuberculous infections may have de phere. .In instances where this nasal reten veloped. tion is disturbed, exposure to silica dioxide It is .well recognized that no individual should be exposed to' dust containing silica dioxide until he has undergone a thorough physical examination, including carefully dust'may be dangerous to that individual, where it would not be to another. . It is believed that certain diseases of the -heart and circulation, of the kidneys, possi made and interpreted x-ray films *of his bly syphilis, chronic coincident diseases of chest. It is likewise obvious to anyone fa the lungs, all may render a*man more sus miliar with silicosis that no person who is ceptible to silicosis than normal. The physi-. exposed to silicious dust should be denied dan at his pre-employment examination must the privilege of. frequent physical examina- follow certain established criteria in this .. tions and x-rays of the chest, not entirely respect, and bar from exposure to dangerous to discover the existence of possible silicosis, * dusts those persons who through existing but to discover a coincident tuberculosis if such exists. disease may be more -ready prey to silicosis or tuberculosis. A man so diseased,should, in protection to himself and to all- with whom he comes in -contact, jbe removed from industry. Let me emphasize the uselessness of a physical examination, unless it be accompanied by properly taken x-ray films, except in cases of gross tuberculosis. . It is the function of jthe physician, there fore, to conduct in a thorough and an intelli gent manner the pre-employment examina tion of all persons who are to be engaged in a dusty trade. The purpose of .this ex amination should be threefold. First, to discover and bar from employment in dust, any person who is suffering from tuber culosis. in .an active,- a quiescent or an ar rested state. A possible exception might be made in individuals suffering from a so called healed primary complex, or a healed childhood in fection. It is well known that exposure to > Re-Examination Needed After the applicant for employment has successfully passed his physical examination and is engaged in a dusty trade, the duty of the physician is not yet ended. This work man must be periodically re-examined, first to discover the early appearances of pul monary fibrosis, but what is even more im portant, to detect the early evidences of complicating tuberculous infection. A man should not be dismissed from em ploymentin a dusty trade merely because he has evidences, of non-disabling silicosis. Workers in dusty trades, especially 'stone cutters, moulders, pottery workers, and similar craftsmen, are usually highly skilled, and it seems unfortunate from a Social and economic point of view to deny them em ployment so long as they are physically able to carry on, especially since the actual dis abling qualities of silicosis are in doubt. 98 Twenty-sixth National Safety Congress They should be denied employment' in a intervals; coh^rringiwidi this;physician, in ah dusty trade if that condition is -found at effortkto<dis<y^tra!^fr;^'''the:llight-!of pre-employment examination, - but:: they : their/joint::lmdple^^^oi^^;!cmdijdohs should hot be barred from continuing an are dahgerous./ Hemu^tdiwelopand install employment in. which they me already- en carefuhy^ui^^ytt^lad^equrphrait. He gaged. Of course; in such instances' you; as must'.t|naags^^,-fln^^n^n a^chemi^ . engineers, must realize that.you haye failed, - and Motherindvufrial/procMsi:where;such because if you had kept, the breathing ;zone. of the worker., free from: dangerous dusts, - efforlstbward ^rembring^fromrthh'dmii^er silicosis would-not be present on physiol zone'pfjthewbrker,^ examinatioa whateverif maybe! In this work of preventing dust diseases in Too many engineers construe this, function industry, it should be evident that the closest loosely.. They, pass ,on, to.the >physidan.as,; and most intelligent cooperation between the his responsibility certain,functiohs.which es physician and the engineer is necessary./. The sentially are theirs; such - furietiom as. dust physician must, through his knowledge! and analyses, - dust /counts, and similar . technical research, tell the engineer what dusts, or,, duties. All. too ofteh it is. considered. ade for that matter, what other substances used quate merely toinstall a fan. . in industry are harmful. He must tell the engineer how such dusts or other materials enter the body, how they leave the body and what they do in their passages-through or their residence in the body. Ventilating devices, in-dusty work rooms must be constructed, only: after.careful en gineering study has given a knowledge ofthe physical properties of the air and of. substances polluting it. It 'is possible -to Must Make Analyses calculate to .a very .fine point the volume of air that must be ranoved from a given spot The' engineer, must in turn tell the physi to remove. tiie, dust originating ,at that place, cian Of the harmful dusts and other sub- and .the. engineer must approach his .task - stances surrounding his .workers. He must from just as sden^tific an angle as the physi- make chemical and petrographic analyses of . dan approaches his. ,* the dusts, and other indicated analyses of the There is no. room in industry -for hap-;, atmosphere in the workshop. He must make hazard methods on the part of either, the dust counts and check his counts at regular physician or the engineer. ADJOURNMENT .3 '