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THURSDAY MORNING; SESSION "'-'.'0.<jt6ber 14,.'i937:-'. ; . .. " . , The meeting was called to order by Voyta of Wisconsin, Madison, who presided'and Wrabetz; Chairman,Industrial Commission . introduced the speakers. i injur^Effiscts ftSvmtThem By ROY E. JONES^M.1).' Division .of. Labor Standards, U. S. Department of Labor, Washington, D. C. *. . The inhalation of metal fumes is a-com-^ cytic celis^and are eliriiinated chiefly ;by way mon cause of"illness among:certain oecupa- of the bipod and'ljhnph.; , tional groups. Two. very different. systemic - -Sayers:and his associates.1 found that only reactions fmay . resdlt' from.-breathing air about. 151 per cent of inhajed particulate containing particulate" metal or metal-com-. matter, suejt as lead dust;.from automobile pounds: (a)-metal'fume-fever;, any acute, exhaust ^asi . was. retainpd .iri the' lungs, the transitory, non^fatal disease causing slight or remainder.-passing out With,the exhaled air. temporary, disability;; (b) :systemic:,metal Dnnkmr.tmdhis.asspdates'and Brown* made poisoning, mild, severe, or evemfatal in its quantitative measurements bf fumes retained effect The same occupational exposure may, in the lungs. They fotind a direct relation produce bpth reactions, metal -.fume; fever. ship between the ..percentage of. fumesretdeveloping following the worker's ! early.ex tained. and the size, of.the particle and ..the posure, chronic systemic poisoning develop density of the fumes, breatiied. They also ing later as .a result of. prolonged exposure. showed'that; slow deep .breathing increased We may' consider metal- fumes as -solid the reaction resulting from inhaling zinc particles generated by condensation -from fumes. Such breathing should increase the metal in a gaseous, states Condensation : percentage: of particulate matter retained. usually accompariied'by oxidationl . : Hazardous Processes There are two chief physical character- - istics of. metal fumes which .bear a direct For convenience we may place the. more relationship to the ease with whidi they may common Occupational environments which be absorbed: -(a) The solid..particles .are .. are likely to''afford a harmful exposure to much finer than atmospheric dust,probably metal fumes in three large groiips: averaging' less than .5 micron in diameter; (b) they tend to-flocculate and settle out of the air as dust. The-finer tiie: solid'particles suspended in:the air,' the- longer the time required, for them to-settle out -Many, of the coarser, dust particles ii^ the air are. trapped in the lipper respiratory tract and by the ciliated celis ' lining the trachea and bronchi, while the finer,particles may be' 1. Smelting of ores and refining of metals. 2. Employment at processes handling mol. ten metal such. as . molding, cutting, and welding operations. 3. Salvage and. cleaning operations, includ ing, the. burning of .metals .or metal ; covered-objects, especially by means of acetylene torch or electric arc. - carried-to the terminal air spaces of the In the first class, the ores or metals proc lungs. Here they are taken up by. the phago essed provide the source for. the generation .99 PLAINTIFFS EXHIBIT PLAINTIFF'S EXHIBIT p I*  \i ;I i : i i \n Ai p i 100 7"wenty-sixth National Safety Congress of . fumes. Such operations are usually per `Metal -Fume Fever . manent and exposures tend to be more con stant, although as a rule the greatest amount of fumes is generated during tapping opera-. tions. . . Likewise, in the molding processes the mol ten metal is the source of metal fumes. In' welding, cutting, and salvage operations, the metal fumes may originate from metal prod ucts processed, coated surfaces of the metals, fluxes used, or from the coating or core, of the electrode used. A strict interpretation of the term "metal fume fever'' does not place ft in the class of- conditions termed "metal poisoning." The reaction, set up. in the body is not directly attributable to the toxic metal, or dependent upon.the inherent toxicity of the metal partides inhaled.-The superficial action of the finely divided metal destroy the tissues, and the absorption of these altered body proteins affects the individual much the same as typhoid inoculation or the injection of other These latter operations may provide ex-, foreign proteins. posurc to a greater variety of toxic metals, but as a rule such exposures are to lesser concentrations. Exposure usually is less regular since the operations vary from time to time both* as to extent and raw materials used. Metal fume fever has long been recognized as an industrial disease. Other terms commonly applied to .the condition are: "Brass; founders' ague," "brass chills," "zinc fever," or. "zinc chills," "spelter shakes," etc. For merly it was^ thought due to the poisonous Atmospheric Concentrations effects of zfnc and zinc alloys. Various . Data relative to the minimum concentra tions of metal fumes which will produce metal fume fever are limited. It is believed by some .that, except in case of the super sensitive individual' metal fume fevers can be avoided by keeping, atmospheric concen trations below 10 milligrams per cubic meter workers in the past quarter century haveshown, however, that it may be produced by the fumes of metals other than zinc; notably,, copper, magnesium, manganese, and probably lead. Koelsch* in 1923 reported upon*the occurrence of metal fume fever among em ployees in sj copper rolling mill. of air. Drinker and. his associates4 suggest - Investigation showed the men to be work IS milligrams*per cubic meter as a safe limit ing under conditions which caused them to i where workers are exposed to the fumes of breathe air containing heavy concentrations' zinc oxide, provided the fumes of such im of copper' dust The symptoms resembled. purities as lead, cadmium, and arsenic are "brass founders' ague." In his report he not also present in harmful amounts. quotes j Kissalt* as showing that mercury, Our knowledge of safe limits from the viewpoint of chronic metal poisoning is like wise meager. Prolonged exposure to lead concentrations in the air breathed should be nickel, .and probably other heavy metalswhen inhaled- in vaporized form caused symptoms similar to those of "brass found ers'ague." kept below 1,5 milligrams per 10 cubic meters Drinker and his associates'*, in 1927 re of air.* In the study of chronic mercurialism ported that men experimentally exposed to among fur cutters* it was found.that cases fumes of magnesium developed the classical developed after prolonged exposure to at- symptoms of metal fume fever. . mospheric concentrations varying from .6 to 12 milligrams of mercury per 10 cubic i Clinical Picture of Metal Fume Fever meters of air. . The clinical manifestations of. metal fume Less than 5 per cent of those Exposed to fever are as follows: At the end of the day, concentrations which did not exceed 2 milli or 2.to 12 hours following exposure to metal grams per 10 cubic meters of air developed fumes, the individual notices a dryness of symptoms of chronic mercurialism, and all the throat in addition .to the metallic taste cases that developed under such exposure which most workers commonly experience were mild. Canavan and his associates* re during exposure. A feeling of tightness of ported upon a case of chronic manganese the chest, varying with the exposure, usually poisoning which developed following expo indicates the severity of chills and fever sure to manganese dust, where the concentra which are to follow. In mild cases the indi tion in the atmosphere was from 10 to 20 vidual may not be aware of any fever, and milligrams per cubic meter of air, 9 to 12 per may complain only of a chilly sensation, fol cent of which was manganese. lowed by sweating and general weakness. Industrial Fumes, Gases and Vapors .101 *| .Exposure to extreme cold may hasten the were those who did not develop fever and jonset of fever and dulls* but as a rule the chills.. Theoretically, those experiencing ir- -worlmr. awakens from sleep with a high "regular exposures and jcomplainihg of re-, temperature and drills, which are quite simi- peated attacks of fevejr and chills' which . lar to the chills and . fever experienced in leave them , in a generally weakened condi attacks of milaria. After they have devel tion would, in a measure, develop lessened oped, nothing* in the way of extra covers or resistance to acute and chronic infection. hot baths appears to affect these chills. Detailed information]regarding the pa-, Toward the end of the attack the individual thology of metal fume fever is not available. sweats profusely and is left with a feeling A search of the' literature at hand fails to of marked weakness. In the majority of show any record of death, from metal fume cases some-weakness is still felt the next fever, uncomplicated. .The illness is of such day. It is commonly believed that hot baths a transitory nature that [most of our knowl and hot drinks of tea or lemonade may suc edge regarding blood changes is the result ceed in partially aborting the attacks, if of experimental work and isolated case re taken at the first sign of respiratory difficulty ports. I such as a dry throat or tight sensation in' the chest. Drinker and his co-workers4 by their experimental work were unable to show that even excessive "sweating" of an . individual 2 to 4 hours after exposure al tered the reactions in any manner. Examination of'the blood of workers suffering from metal fume fever shows a In view of the fact that zinc is relatively nontoxic, land of the conclusions expressed by Drinker and Fairha!lu regarding the hy gienic position'of zinc, it is difficult to show why chronic illness shoiild result from ex posures producing simple metal fume, fever. It would seem, however, that in considera tion of the recent worjc .showing the role gradual increase <in the polymorphonuclear leukocytes which begins toward the end of playid by zinc in the treatment of diabetes with insulin, possibly jsbme investigation the attack and persists for some time after `the fever has disappeared. This increase in white blood cells appears to have a direct .t .bearing upon the degree of temporary immunity established.. . should.be made to determineif-exposure to metal fumes . capable of producing metal fume fever may not affect' the endocrine system, especially, in' persons with. some metabolic disturbances,] such as'potential , This probably accounts for another char . diabetes or 'thyroid dysfunction.' acteristic clinical observation. The workers are most likely, to be. affected after a vacation Differential Diagnosis period. More cases develop after a holiday Metal fume fever may sometimes be over or on the first day of the. week, after an looked,' unless the physician considers occu absence of ipne or two days from exposure. pational . environment jThe condition may The condition is found more frequently simulate attacks of griplpe or bronchitis; or, affecting new employees or old employees if in a malarial region it|may be mistaken for returning to;.work after a prolonged absence a fresh attack or a. relapse from a former from exposure. attack of malaria. Careful study of'the As a rule* gastrointestinal disturbances are ' blood will aid in. diagnosis pth'ose-suffering seldom complained'of except in cases where ' with grippe or bronchitis seldom show the . exposure has been to fumes of substances increase in white cells usually found present affecting the digestive system. For instance, in persons suffering from metal, fume fever, it is well known that zinc coated metals con while those with malaria usually show the tain. other toxic metals as impurities. The organisms present in their blood. The dura welding, and cutting of these release: the tion of symptom? is ustially less in the case toxic substances together, with the fumes' of metal fume fever. ( from the zinc, as well as fumes from certain However, it is not uncommon to find per fluxes which are used. sistent rales upon examination of the chest We have no conclusive evidence regarding several days after an sittack; However, in chronic effects produced by repeated expo persons with grippe cjr bronchitis, these sure to zinc- fumes. A study of workers in rales are usually, assoaated With a slight brass foundries11 showed that the group ex elevation in temperature; which is not found . periencing attacks of metal fume fever were persisting in metal fume fever, uncompli * in Somewhat poorer physical conditiori than cated, Massive exposure producing metal i f 102 Twenty-sixth National SafetyiCongress ?i fume fever may. be followed by. attacks of. toxic, .;thepp3sibili^,,of poisoning, from..; in- bronchial pneumonia, as a' result, of pul- haling -fumes generated;invthe processing of monary irritation .ahd infective organisms any metiii,sfipUdjrimys;ltey^(miironsidera- commonly present in the respiratory tract tion.. ?^ilc^zmc*-itsaf^may* ite;;relatively Metal particles are not the only injurious nbntamc,"it ; ^ in a substance present in fumes 'generated, by . form frec'frpni'toxic substjiuii:esHsuch; as some industrial processes. The use;.df:.an leadf .amnic, selenium, cadimumi ;ahd many acetylene torch,ina space, with poorventila- tion has resulted in incomplete, combustipn <-Following the>imtiri:attackofmetal fume of the gas and the. liberation of carbon :;feytf,t:biecause;jdf.-tiie'~;temj^raiyvimmunily monoxide gas., , . ;whi(A thy, deyeiop, work^s may contihue Doig and McLaughlin^ reported upon an under ' conditiom which;; caiuedvthe attack i-1 illness affecting,wdders of galvanized metal, and not suffer:; aVrecarfence.: .It -must-be using an electric arc., The men complained borne in mind thattiitee ve^ cohditiohs may V.\ of lung irritation , so severe that their spu afford exposure $b;othef tpiric metals which tum was often blood-tinged. Investigation have cumulative effi^Xand - later lead to a showed this to be caused by excessive con ; chronic poisoningif atmospheric concentra centrations of nitrous fumes generated by tions--.of-the;fumwarelcept'below; those the processes. X-ray examination of the . capable of producing nietaii fume feyer in the chests of several.in this group, who had been new worker.e the dances of chronic poison- employed for many years, showed changes ing by the toxic metals present as impurities thought due either to the prolonged irrita are definitelyreduced. tion caused by nitrous fumes, or possibly to the fumes of silica inhaled. The electrodes used were silica-coated.,. ... OntheotherjEand, however, .these im-.. purities may bepresentin amounts sufficient to lead' to' chronic illnesses later, although Chronic Poisoning by Metal Fumes - the concentration of fumes - has never pro duced metal fame fever.' . It is generally recognized that the. most serious exposures to toxic metals in industry : Clinical Pictureof Chronic Poisoning occur in occupations. where the worker- by Metal Fumes breathes air contaminated with these poison ous substances. It is true systemic poisoning ? The .symptoms .produced- by poisoning by metals may develop in an acute or. sub . from, metal;fumes, will "vary. Some-metals acute form, as a result of massive exposure .. affect chiefljr'theinenrotB. system, others'the. However, the vast majority of such cases lining of- theblood capillaries, while others are chronic, caused by frequent and pro^ exert'most characteristic injury upon the*, longed exposure-which leads to an accumu blood-forming; Organs. lation of tiie toxic metal in the body. Poisons Generally Speaking, tiie clinical picture of entering the body by way of the lungs, to jmetal fmne.iever,i regardless ; of the metal be eliminated must be taken up by the blood responsible, .. varies.: only in; severity, while . and lymph. When present in the blood, they that.of metai poisoning per. ,se .varies with are carried to all parts of the body. the particular metalfume inhaled and with Poisons taken in by way of the mouth may . the .degree cif exposure. For example, . not be absorbed, but be passed out with the Aiassiye,.doses oflead fumes ,inhaled may feces. If absorbed, ittnay be trapped in the produce sudracute conditions aislead enceph liver and returned to. the intestinal tract in alitis ; and : sevWe j^tebbll^tiUal compli- . the bile, and eliminated with tiie feces. Some,, cations; while.continued exposure to smaller `it is true, may be. transferred by the blood concentrations" will. 'cause' such, chronic . to distant organs. . Most heavy , metals-.and changes' as. anemia, lead palsy,' and dironic their salts are true protoplasmic poisons.. nephritis. : . . Some, such as iron and zinc, are more com mon constituents of body tissue. Tiie action of thesetoxic metals is generally cumulative and no immunity, temporary or permanent, may be ` established if exposure is to sufficient concentrations: - Exposure to heavy concentrations of mer cury vapor leads,to acute:nephritis,; saliva tion, and ;diarrhea,:while.thembre common industrial,exposures to but slight concentra tions .. will eventually, produce - the typical mercury , tremor and psychic chahges diar- Because of the fact that metals are usually acteristic of chronic mercurialising 'Strictly Pi its: s6^y,'md<iddiH:nbi;limii entratice to .the ; worteobmV meansjpf.hppdsor '(mdos^prbcessestS^-. WUUeuatpratpQt^ding^ are a very ;im- portan^^^<^;:m];{|iagndsb,:ith^ cannbt be: reUed\ jHp^7as-^e^le{evldeiicb necessary: ` Both-lbcal eMaust ahd imbtdsed methods ; Prevention of,.Metal Fume Poisoning are ihprej'effectiye'::if^spiwial/attdition ;is given to:general i^rl^bh^vehtilatidni^Gis- While /the ^ responsibility of controlling health ha^ds/associated 'with Exposure to posal of fuines^ t^ esses add-lb<^rexhaust ^ fumesp:;toxic..jhet^ the etnpioyer^.(^e^w eluninatl6n: of such ha^rds^r^v'oidy.^ the, whole into the Work places by/general Ventilation. hearted cpbperatiohof emptbyers,mplbyees, MedicalControl the Stati^^/p^ agencies. ;v- Three^fundjmiehtals contribute ; most to actual^rCTentiotuAThor are: Good housekbepin^^sup^itldjbyjengmeeringcontrol of hkzardous processes, and intelligent .. Adequate medicalsupervision entails spe cial bare in/the^placement!; pf 'workbrs^and should not he ainied.at the selectibn bfonly super-men^ sihceit is practical to. inialce'.work niedicai supervision. place3safeibrtheaveragehmn.;Individuals with ? serious kidney; i;espiratory, 'or other .Good Housekeeping . ' systemicdiseases should notbe; pldced'where1 they maybee^^ con We think of good housekeeping as ap-. centrations of-toxic-fumes! > jV. - plying to ;|d^n floors and work benches; Whefeprbcesses:a^ be poten -materials, tools.and processes arranged and tially ha^dobSi;ah';ih^rtant>chbdc on-the maintaihra:ingpbddrder;ad^uateiighting,'. effidencyof-iei^ gained - ) and no ovd/crowding^ men through^Tegtijar! rpen^c/.bMimination1 of and materials. !A11 tHe ^l;do much to les sor the concentration of tpixib fumes ra the atmosphere, butjsddom, is the control of. processes. so!effective' that some fnines do an bpportunityisaffp^ -' not escape into thegeneral air of the work measures sp -. eff^velyVthiaf /tEe .workers room. . From^here they' may be inhaled, or shpwing early>sigt&pf absprptibnmay^afely -may cpntaininate the bodies and clothes of cohtihue at mem-reguiaf/jobi; Routine rec- the workers.; So general workroom ventila ordsof illneSsshbild bekept- tion is a/factor..hi>^^`^Qi^<ke<pmg.`^^: . ' A^; abhormal'rate7bf^al)sditeeism due to The provision; of adequate washing.factii-. ties is a prereqmsite. Under certeih\cbndi- tions lockers; and ?showers-..for. workers /are necessary for :tiie; safe operation of many, processes.'. ..' ''J':.`| _ ilhiessamphg.moccupationalgroup,regard- lpess of.'the diagnosis . repprtbd, r, -I ^ rrri t*'r, I, * j i sh6uId call are any environmental ing theprimary illness, ions aggravat- As a rule sweeping suad clesming shbuld be Personal Protective Equipment but what:is rmore imi^r^Vfbthefi wdrlars will pot jbe subiebt^tto^adyimcrease in-at- ing methcdsVlf^cuumioriwetiiiethbdsiare used, :accumulated ;dust is; more effectively andsafdyremoyed. - If proper.. attenhpn is, ^yai,;tP the;tiiree fundajpehtels/.rawtta^ ing, .medical ;aind j,ipneering;,cbntrpl-^nfy spS^Ci/andL4tmusuaJ ..temergbiicg exposure, will; catifortiieprovisibn pf' personalprottiye;e^u|pment,/.;. ;r_;V i The masks or;, respirators provided .work- r. !. f /. 104 Twenty-sixth National Safety Congress ers who must necessarily be exposed to Bibliography ?' metal fumes should-jbeof spedal.'construc tion and adapted .^>:.rite;processes-and ma terials .used.. The United. State; Bureau, of' Mines'* has, after testing, approved certain 1 Experimental Studies withe "Effect* of Ethyl - Gasoline".and: It*.'.CombustionsProducts; R.R. Sayers, A. C, Fieldner. -W. P. Yant,ndB. G. H. Thomas. U. S. Bureau of Mines, Monograph'No. 2, 1927. ;:.V .7;-> . types of masks for workers exposed to spe cific metal, fumes. . No filter type of respirator capable of pro tection against toxic metal fumes has been submitted for approval. While two or three filter type,.jrespirators havebeen approved for protection against lead dust/ the. use of whidh may in a small way reduce the hazard of fumes, they cannot be relied upon for full protection. . Filter type respirators approved for protection against nuisance and pneu `Quantitative Measttrementsofthe .Inhalation, Retention andExhalation .of. Dusts and. Fumes by Mam .1. Concentrationsof"50' to'450`.nup' per cubic meter., P.-Drinkeiy-R. M. Thomson,and.Frim,J.L. Jour. Ind. Byg.,'VoL lO,No:l,Ja%1928, ' Same as i. IL &raantrations below SO mg. per cubic meter.' Brown. G E, Jour..Ind..:Hyg^ '.Vol. 13, No. 8, Ocb.T931i Studiesin DustRetention. III. Factors involved in'die Retentiori'bf Inhaled Dusts and Fumes by Man. -Jour.; Ind. Hyg., Vol. 13, No, 9, Nov. 193C . .... .. ... .... *MetalVFume'iFeveri; IV.'' Threshold Boses'of Zinc. Oxide, -Preventive.'.Measures...and' Chrome Effects of Repeated Exposures.- P.-Drinker,-R.- H. Thomson, J. L.. Finn: -Jour.-Ind. Hyg., -Vol.- 9, No. 8, 1927: - ' moconiosis-producing: dusts will not protect. _*Lead_'Poisoiing;ra a Storage Battery Plant.' the user from toxic fumes. Fuhlic- Health: Bulletin -No.. 205,: June,M933. *A study - of - Chronic Mercurialismin. the Hat-: Several of the hose-line or positive pres tern Fur-Cutting Industry.. Public Health Bulletin sure type masks have been approved, but No. 234.' ' j- ; ' ' : .- . `.Chronic Manganese Poisoning. Report of a Case there are certain limitations to their applica jnth Autapsy Findings. Canavan, M.M..Cobb,S., tionwhich make them impractical for use in Drinker, C. K.: Arch..Neurol. and Psychiat, 9:270- 1934. .- seme kinds of work.! Metal Fume Fever. Koelsch, F. -Jour. IntL Hyg., Vol. S, p. 87, July, 1923. Substitution ,, * Ueber, das Giessfieber tfnd verwandtegewerblicbe - In a vast majority' of cases, resort, to Metalldamnfinhalations-lcranlchciten. - Kissalt, . K. Ztschr. . Hyg., 1912,71, $72. substitution is an /impractical method of eliminating health .^hazards due to., metal fumes. The raw materials used' usually have "Metal Fume Fever.IIL TheEffects of Inhal ing Magnesium Oxide Fume.' P. Drinker, Thomson, R. M., Finn., 'J. L. Jour. Ind. Hyg., Vol. 9, No. 9, 1927. .* . : special, application. ; Furthermore, substitu tion is often a dangerous .practice, , even though it is practical. Instances may. be cited, where the substituted product has proven equally as dangerous as the one it replaced, the only 'difference being that less u Health Hazards- in a Brass Foundry. Public HealthBulIetibNo. 1S7. s.. ' "Zinc' ii 'Relation to 1General and Industrial Hygiene. - C. K. DrinkerJ L. T.- Fairhail. -Public Hemth Reports, VoL 48, No. .32, Aug: 1933. . -"X-Ray- Appearances .of.the Lungs-of Electric Are Welders.A T. Dolg and A L ^McLaughlin. Lancet: April 4,1936? p.771. .- was known at the time concerning its toxic properties. "list of Devices for.Respiratory Protection Ap- proved by the U.S.Bureau of Mines-W. P. Yant Bureau of Mines Information Circular No. 6918. Electroplating Fumes and Vapors and Their Elimination By P. B. RASTELLO, M.D. A- Temstedt Manufacturing Division: General Motors Corporation, Detroit, Michigan The industrial physician is responsible for formed on changes in methods and materials the health of all -employees in his plant, in that may influence those hazards. < so far as their health may be affected by Thus -fortified, the physician occupies a their occupations, and their, environment strategic position in the .hospital, as the em Consequently he must be familiar with the ployee invariably comes-:.to hhn.first with' various jobs and conditions under which the complaints which lie may associate, with his men-work to know definitely the associated work or.which.hrei-of.a'natnre.that would health hazards. He must work closely with . warrant an investigation which, may lead to the safety, maintenance, chemical and par-' the discovery of an unhealthy condition. chasing departments to keep himself in One of the processes which may be sus pect! elect mete ing. < vage chen alka offei Whi the also offei ; worl satis effic P< bodt mou latic our roul are. F may and thre cyai prot bloc . s: witl ene as c Sin. oca Ii and . den Iridi pre' hav bod ing Ii res] onl; ano the call fur the the par 1 era r.,i V.j&Ss*.:! Industrial Fumes, Gases and Vapors 105 pected of involving a health hazard is the hazard, but out of their properties'as gases electro disposition of-, metal; ..Inpreparing arises-one of our. greatestvproblems in the ) metal for;plating as well as` during the. plat control- of electroplatingfumes iandvvapprs.- ing ,:of ;.sal- As the. gas is liberated*rit;foriris tiny bubbles vage material after/platingi; a 'number of' in:the. solutiohwbichriseab6ye:the surface chemicals iare used, suchas solvents, .'adds, and break, tin-owing a fine;spray pr mist of alkalis, metaisand'sal^ and bath solution into ; toeair aboveMthe; tanks ' offetisive:fumes> aridivapors -are; liberated.; which may be.inhaledby theworketoiCon-: While, it is trne our prime interest concerns sequently. to understand .and evaluate our the injurious!, fumes' and .vapors,- we . must hazards,we mustknowthe.bath constituents also interest: ourselves in ithenon-injurious in: all electrolytic processes,; :y ' offehsive. types,; since they may affect the : worker's; mehtalattitude,giving rise to dis- satisfaction whirii in, turn may. result .in' in efficient; work. The materials coming to the plating room, usually have a film of oil- pr grease on them which must be removed; and-the surface treated before they are placedin-toe plating, Poison is "commonly introduced ' into the. solutions.. This ; is accbmplished by- dipping body three;;rputes, ingestion: through the the 'parts in a degreasing; solution such as mouth, absorprion thibiigh the skin or inha-- xylene or placing them-'in i .vapor. bath as latioh toroughthe lungs. - In electroplating our greatest;hazardlies. in the respiratory route; jthe ingestion'and absorption- routes are. of lesser; importance. . trichlorethylehe...: Usually this:. operation is carried out In open tanks; and ,as~ bath sol vents .are highly, volatile*; somerof : their fumes escape and. contaminate the room Fiimes andvapors, such as heavy adds, ,air., . .. v.---..- may enter the respiratory tract ias fine spray Xylene though less toxic than benzene and and produce local -reactions- in the nose, throat ind lungs, while otherssuchas hydro cyanic acid pass through the lungs without toluene has' some narcotic`action on the cen-' tral .nervous system. Tridjiloretiiytene Is the most commonly used d^CTeaser; and is ca producing any local symptoms and enter the pable of producing generalnarcosis.Workers bloodstream. -at.riie taoks coinplain of/pddinesS and oc , Skin absorption is important in connection casionally. loseconsaousness,biit.fewdisafhs with the coal, tar derivatives, benzene, tolu have been reported. : Trichldrethylaie,.also - ene and xylene and,the petroleum derivatives has an important;chanicteristic-.that.must be . as carbon tetrachloride and trichlorethylene. borne in mind--workers have been known to ) Since these :are all; Volatile, poisoningmay become addicted to iteuse.. occur by inhalation as well as by absorption. Because of toe!lugbly; volatile-nature of . Ingestion Is Rare these solvents .it. is; impractical, to .attempt exhausting toe. tanks,. We .found ,we: could Ingestion of poison by-mouth occurs rarely -, eliminate toe xylene with its hazards by in and isj usually the result of.,a definite.acci stalling closed.tanksystems of trichlbrethydent [However,, in, the lead.electroplating-. lene washing and vaporizing, passing, the industry, rigid precautions must be taken .to parts, through .toe sprayandyapor chambers prevent toe ingestion of lead salts .that may. on conveyors. ;,This-: ^so.rcriiotoiatecL. ourhave been deposited oh the clothing: and trichlorethylenO hazard andthe penetrating, body of men whilewprkmg aronnd the plat sweet smemng,sickenirig odor in toe plating: ing tanks, ... rooms which had been a source of complaint, ' In general-in all electrolytic processes ir respective of theconstituents of the bath only two gases are libeiatbd. Qiq'gen at the anode, and hydrogen-at ;the cathode.' Since, and concern'to;toe Workmen. Carbon ' tetrachloride is . used in some operations, but-its use should be'discouraged because of its extremetoxicity. the -anode efficiency isalways high and the Following toe degreasing process the parts; . cathode. effidency; rdativdy*16wer,,:iiuid the. are washed, in a strong hot caustic solution further: fact! toatthe; gases are. liberated - in to remove organic 'particles' of dirt This the relation of two hydrogen to one oxygen, washing is moreeffectiyfeifan electric cur the gas frona the anode is hegligible com- . rent is passed, totbugh the solution;'which by pared withthat at the cathode. toe bombardihetit of` hydrogen - gas on the - The amount of oxygen and hydrogen lib part at the cathode -produces' a scrubbing erated, as such, is of no consequence as a effect Since the aiiriof the elrirtrolysis in 106 'Twenty-sixth National. Safety Congress this process is to produce gas; and none, .of- is the current is usedtodeposit -metal, a large compared.-mth-the^OT^ amount of gas as. hydrogen and oxygenis liberated and considerablesbath solution is atomized, into the air.-Th^^ ; composed of strongalkalis isveryirritating to the respiratory, tract, and the tanks should - be exhausted automoWeflmidwarie^;i^.(m?Sts^epbitition: In some cases' other ..operations art- re wc;-usCTa$qb^ quired : before plating, such' as pidding- dnd add ahdfavW bright dipping: The pickling hath contains addi :>Since^ir;dfiaericyvOitb:cKromi1th. weak solutions of hydrochloric or sulphuric at.theteatbcde<ii .Oidytabout. 15 jw;ceht,: 85 . .add and some nascent hydrogen is generated., per cent of ^e cturen^ . Since iron, steeVzinc, copper and lead may. tiontof; h^rogengiui;'^ contain arsenic as an. impurity there is ,al-: ways danger of hydrogen arsenide gas being tanks must'beeffidtti^ pollu- formed from time to time. This is a power- tiom,.:.Crornic't:add.;is'rrda^iidyj}n6hrtoxic. ful hemolytic poison .and early symptoms of Its.: effects .-on tite^body^e^amily^recog- poison appear soon after the gas is inhaled: nized, and: probablyTpt\ti^ it has All pickling, tanks should be exhausted hdd.too important a part in thediterature In the bright dipping.of brass a concen trated solution, of sulphuric and nitric add is used, and large amounts of nitrous oxide or nitrogen dioxide fumes are liberated when, the parts are placed-in the solution. The oxide of nitrogen has a strong, load action on the respiratory tract and may produce serious lung damage. It is unfortunate that that gas is not very asphyxiating; the worker may continue to inhale it without ex-, periendng anything more serious than a = . ' ` ' on toxicology.ItinayprpduceulcersDnthe skin where concentrsdedsblutionshave contacted,. but outside .of their .slow; healing propertiel:,ti>ese !are' ibf; little: consequence. If not exhausted properly' it produces in Workers-erosions oTthe.h&alseptum,which frequently go,on to prodn^, permanent per- forations /which are. annoying but .dp not predispose to any disfiguration or health problem. Like nickel.in. susceptible, individ uals;. it produces dermatosis .which invari ably clears, tip on removal of the person choking sensation until some hours later. from work in: the sensitizing materials. Poisonous Salts Used In the actual plating solutions we deal with poisonous salts of sodium, copper, zinc, nickel, cadmium, gold etc: The cyanide com pounds are oar greatest concern because'of their high toxicity. Plating room.workers should be instructed as to. the dangers in-, volyed in the handling of the various com pounds and solutions, and the possibilities of the formation .of hydrocyanic add gas in accidentally mixing add and cyanide so lutions or promiscuously stopping these so lutions on the floors or spilling them into stagnant drain pipes. In the electrolytic process the hydrogen gas bubbling out of the solution will atomize these compounds In the air, and the tanks must be adequately exhausted. It is probable that some cyanogen gas is mechanically thrown out of the solution by the hydrogen gas and undoubtedly minute amounts of hydrocyanic add are formed. However, the tendency of the cyanogen Js to return to the solution, so that the hydrocyanic acid formed In tiie process of stripping `salvage parts for re-working, concentrated alkalis are used. to remove chroma and concentrated sul phuric add to remove nickel,. copper, and zinc; or an electrolytic bath of sodium ni trate can be nsed to remove all the deposited metals. The tanks In all these operations must be exhausted. ! The elimination of fumes and vapors in tiie plating, rooms is for .the most, part the concern of the maintenance engineer. However, the chemist may eliminate them by changes in methods or solutions, designed to stop thdr production, and the safety, en gineer may eliminate them from contact with the workmen by the introduction of hoods, masks, gloves, etc. Probably in the future factories will be air' conditioned, and our problems of air pollution will be minimised. When we analyse the problem of ventilat ing the plating rooms, we are confronted with many difficulties, Exhaust systems of individual, tahks. designed by rule of thumb to operate with one hundred per cent effi* Industrial. Fumes,'Gases and Vapors 107 dency,- i^ equal* ;inay fall ing,- mid, regular pe^odic. checks ^should be ^of air. ntade-.with &esejseveral' times'-a'yeaii or .as movmeitts^ hatu^^s^is^j^o|dly^^a^;b|. an induced 15 Inrthe final'analysis. we/areLhof interested systanjbpS^^Kg^^a^^i^temi/.I.-have; merely .jn.:^ or ardora but seen';ra:mau^^^^t^cag^ly^{)^cUdmhg as cni ,is: wi^fisf.^^^tjxir^^e^re^^kresKdb^xBS, and ^tbeillo^^ce^l^^^sui^s^aiy ".ear-" to-headth, how\riiU(&'b^^^^ as a":$:l;''./- %/' : .chemiral itmalysis jpf.:tfie^air is-jthe only; way Other cdh^dons tend to iinbdance a well 'tpjdeterauhp;4iis.^:::~j-,V: construct^system,'! suchas ppenwindows, . ' We haveiintroducedinour plating rooms doors,: slqfrlljBrn^-rall,-\b'VwlticAi>prbduce j air . sevei^maduh^ samples, currents.: ^t;may::divert;iunies arid vabors 'a3.,djbi#d;hyJhu).Buireauj.pf;daiiies^ahd^.-the from, the'rta^>asvtKQr^fpass:to the^various United;::SfatesjPublic:Heaith Service.This exhaust.^hoqdsciri.theVri^ Whileroom' , meth^^essehdyiy'CcbhsistS'bfdrawmg'-air temperature, humidity, barometric pressure, through; a^spluflph^m;avo>]lecting^botde at and outside airvelodtiesi.likewise influence a* fixbd rate, .the aifsparsisihg:throughan im- theexhaust^tein.^ pu^er'tUbe^^ is ' Remove Fomes at Source -. . increased;t<jl abput'^Wimiies an' hour.. As it ! strikes-the tetibiri1^ The rardiiiad:!^^ . .air'.is' broli^j;up^mto:;minute,bubbles, .which the system to. remove.the.fumes and yapors fadUtates.vahsorptibn jnithe cbllecting solu at their pointjpf , ojrigm*- In electroplating tions^ By'using different solutions oil .a,series tanks the 'American - StandardsvAssoqatio'n . ofsblutioris,;'^ or has recommended l^t" :t^; ^^t;>lMe^r6tn - gaseous 'pollutant isi tetrarted .fibm,. the six to eight 'inches ;hb6ve the solution'.level, testedair, and a.cheinist;makes'his analysis. so that. tiie\Si^;from;: the brealdng rgas . A,. cqmplete. air amaiysisjs\hbt necessary, bubblesmay^bbboUected.;Itfurdierfecommends that thelpoint:be hot more' than three as, this Would:,-entail a y^.'lerigtby; arid ... difficult prpbldh.v:Knpwing. 'whatfumes.'and feet in height 'from the level at 'whibhthe vapors areformied frpm&ekmpwntcpns^tu- operator. is"shmdmgi;^t>'dra,w'>pff tiieftimes before they rich^his'brkthing zphe;!: Over harmful, ones that may be present.in the air head hoods and exlktisjEs'may preveht fumes atid not'in-thesmidlUi^easurable.amounts from entering ffi^'^m air, but they ate of of harmless chemical Lcombinationsthatmay little value' tbfthe \wprker standingat-the be.formed.. .. / tank. Ttmks shbuld ^as narrow'as possible : and should be vented on both .of. tho long sides, to aid in efficient exhaust of the solu tion .area. To obtain as representative a test as possi ble, the collecting botfle is placed at face level, near the operator, and air is drawn through'the solution during the entire period Too frequently we satisfy ourselves, that be. is working. The tbtal air volume that has our plating rooms are safe for employees to passed.tiirough;.the'collecting solution is work .in, because we have complied with all roughly equivalent to the amount of air that state rales and . regulations relating to the would pass through the lungs of an average removal of fumes and {vapors, and because man during the same period. state inspectors pass favorably on our sys-. terns after their, casual survey. We wa!k: through the placing room using our noses to Long-Time Studies Made detect the presence of lurries'and place our At some key- points in the plating room hands against the exhaust hood to determine we are installing air analysis equipment the efficiency of the systems. While it is true which is to bis runcontinuously, and deter our flye senses are valuable In the detection minations are to be made oh;2Mrour collec of hasardi,Jt.is folly to rely on them to the tions or more frequently if indicated. By exclusion of the more scientific means at eur this procedure \ve are Ible to,make more de disposal. Pitot tubes, anemometers, manom tailed studies of our haiardi at fixed points eters, and swinging vane: velocity meters are over a lohfc: period of; tithe and; attempt to available to test airvelocities and determine find and Control conditions in the room that the air volume the various ducts are carry produce fluctuations in bur air pollution.. - 108 Twenty-sixth National Safety Congress Along the same line of health research we Until such a time as-the industrial hygien have formed a health hazard committee, ist and toxicologist'determines for us definite composed of representatives of the safety, safe limits of various poisons in the air in chemical,' medical and maintenance depart which an unprotected man'may work, we ments, whose duties are to discover, discuss must follow ah uncharted course with cau and correct. unhealthy working conditions. tion, ever being on the alert for signs and The safety man observes, the chemist de symptoms that may lead to the discovery of termines, the physician interprets, and the new health hazards and the establishment of maintenance engineer eliminates the hazard. safe standards. The scientific study of proc This method of approach has worked out esses in our plant by the chemical, ventilating well, the general discussion invariably con and safety engineers co-ordinating, with the tributing to a better understanding of prob physician may assist materially in .determin lems and a more rapid solution. This is ing standards of. safety in handling of toxic especially true in regard to our plating, substances; for the toxicologist sets his roams, where we are dealing with highly standard on the basis of the symptoms or technical processes, the intricacies of which pathology produced by a known quantity of are thoroughly understood only by the substance administered. chemist Any standard we set up as safe will not There are no reputable-industries whose - necessarily mean that -no man will exhibit management, even in the absence of state symptoms while working within it. As long compensation laws, would ask their em as any toxic material , is in. the air, certain ployees to engage in work that we as physi susceptible or sensitized persons will mani cians find injurious to health; and there are fest symptoms, just as individuals in other no dusts, fumes, or vapor hazards in in walks of life are. sensitized to pollens in the dustry that cannot be-controlled by a com air, foodstuffs, drugs and local, irritants to petent engineer, if he knows what results he the skin. is to obtain. We cannot hope to correct this condition, The use of masks, hoods and respirators but we can control it by removing the suscep in the plating rooms is an admission of de- tible- person- to work in other departments. fiat by the chemist and engineer. Workers By analyzing our aiF, establishing reasonable invariably cheat at intervals, if forced to standards and keeping our polluting sub wear a cumbersome hot hood or respirator stances within.these standards we can at throughout the day, and during these periods least b.e assured -that our- -workers are not they are subjected to the hazards the appa being exposed to quantities of toxic sub ratus was designed to control. We should stance that may produce-serious damage to consider these only as emergency measures, their health. ADJOURNMENT