Document ybGLe1Rr30XED9LZwjJXGkeQD

FILE NAME: General Motors (GM) DATE: 1947 Oct DOC#: GM008 DOCUMENT DESCRIPTION: Transactions - National Safety Congress r Wwi.i.,#"K" t % a t i 6 a e tw n & 35TH N A T I O N A L S A F E T Y CONGRESS i. , I % 'Sxc .2: "til / ?V7 VOLUME V AUTOMOTIVE AND MACHINE SHOP SECTION A T I 0 N A L SAFETY COUNCIL, INC 3 NQ. W A C K E R D R I V E - C H I C A G O 6, I L L .CJL VScxor Cor*rodueta, Detroit, r-- Wagner Electric ->t L y , MianToledo, Ohio - Company, De ment. industrial ping Company, Milwaukee, Wb >ivision of Chrysler wtfaauring Cota f. .. <>. r , u a v Detroit. Midi-', n a U rt Road. Pittlheirgh. Pg.; S.UECHCMi: . J. MeROBERT A. LT. COMDR. M i Carp., Milwaukee, 1h*apfc 0 . Autom otive and M achine S to p Section 7 MONDAY AFTERNOON SESSION October 6, 1947 . Frniding: Da. A. L. Baoows, Medical Director, Fuller Body' Division. General Motors Col poratioa E ecognU km a n d C o n tro l o ! Font a n d D ust E xposu re By V. J. CASTROP Research Laboratories Division, Gsneral Motors Corporation itincm which can be attributed to the oc cupation nay occur in the autotnocive and allied industries. While occupatiocul disease a m are much fewer in number than time resulting from accidental injury, there Mill remains the need for vigilance in maintaining a healthful working environment. The re sponsibility for employee health is tlclegated hy management to the medical director with the safely director charged with matters per taining to safety. For the smooth functioning of cither department it is necessary that them individuals work in close harmony with each other. A safety engineer who is capable of recog nising condition* which may be detrimental to the health of the employee is an excellent teamimic for the doctor in any employee health maintenance program. The safety en gineer need not be capable of actually cam pling air in the environment or designing a ventilation system ka the control of toxic materials. He should, however, have knowl edge of the materials which have been proved harmful, should be fairly well rnformed of how choc materials may be used mfely, have tome undemanding of hour control measures which are normally recommended hen such materials are used. The intention is not to present a highly lechnfcat d iscussion of fume and dust ex posures or detailed information, regarding sentita(ion systems, as such matters are of interest to the professional InchMrisI hygien ists and of comparatively Uuie value to safety tnginetas. This dfecearion will be limited to the more basic principles of Imhrvtrtal hy giene as they relate to fume and dust experntm, to indicate what control meamtes at* available or uses! to protect the era- ptopert harirti, and, to a ll to your attention o p m tk m and maserialt which are commonly mad hi the automotive and Sled ImadhtnmgcrJiew at the same lima Indicating the |M W accepted opinion as to their effect on health. Many condition* ate corrected or improved because of reason* other than their effect upon the health of the employees. Better products, better employee relationship, reduc tion in maintenance of equipment may be cited a* justification for management's de cisions for such correction or improvement. Generally speaking there are two means of entrance of toxic compounds into the human body under industrial conditions, namely, by ingestice or via the respiratory tract through the inhalation of fumes, dusts, mists or gases. Ingestion is of importance if took materials which have a systemic effect are used and adequate trashing facilities are not provided, or, where the employees are slovenly in their personal habits. Inhalation is considered the most important portal of entry of fume* car dusts and the partide sire, therefore, be comet significant in evaluating an exposure. The particles which cause the physiological changes are throe which are small enough to remain suspended in the air and not those which immediately fall to the floor. Flying particles, which are of concern to a safety man and for which he advocates the use of goggles, are not of hygienic significance since they are riot of respirable sire. T o judge the seriousness of an exposure by the quantity of detritus adjacent to cm operation i* often misleading. T h h is espe*tally true where mechanical vcndlatloo hi>s been provided which will remove the fine material but is inadequate to trap or convey the larger particles. In evaluating an exposure it h necessary to axwider the tmidty of the material, the duration of the exprouw, the avenge eenceatratkm of the cnnuBtlnant with special aueoOoa being paid to them operation* which pnxiure high concemratteew at aome pfoue of ag ra n tin g cycle, and the moasum whMh *** provided to oocerol the exposure. StrfIr&' M . *` . IT\f,v*: v- ^ -' :-S iC f if e - . * > *; V ` 7- . -*sM f * *f-, W: oU- f- *4..*: 4 ii- V . -lK="* %-s '-'"rf1 r 8 51* N ational S a ftty Congrats, 1947 Medical records of the individuals w ljK H d to the exposure assy be of value if the w in lnstioni s r ibonugh ad frequent ad no of a cursoty type. It aaat be imoambmad (hat occupational diseases am slow in develop* mem and in soasc latte(tees lading 6. dloot. Slow changes any not be detected and the mete te a that cases hare not occaned Is ao definite assurance that exposures to kaorra toxic materials atay be ignored. The detersaiaatioa of the cwacm rattoa of the toxic aaaterial ia the sir is iaspoetaat la evaluating the exposure. Tetts of this type are not only indicative of the degree of am* lamination bat in s o w instances which o p nation It the major ofltadm. The apparatus used ia eeikcdng the eonuminsnt aad the asethod used la s a lu tin g the amount prcsettt in the simospbete vary with the type o f a a tciiiL Toes o f this type are spccialiaed in nature aad are hem with many pitfalb which can lead to very maw* out results and condudom if done by other than experienced pm m tnri. In a discussion pam latag to Made a a teriab it is generally aecenery to p a n per* mtaibie concentrations or as It is aametuam expressed -- auximum aBowoMe coaccMxa* tions-penaasifale l a i n , or thtm hdd Imha. These tenas are used extesatady by terim ufct hygienfats to indkace m aueriaitam e f a substance ia the afar which w a d d e d compatible with good health. The Rsoit tarn* ally applies to exposana of eight hoar* dam* dost for a pielupgtd period. The limits are, for the a n d m at, advisory standards or bench amrte which are p e w tkal to a e o . la general, these Had* am de> rived (ram three types o f evidence eh e f which have vshae and Kmimtloaa. aMwfdaable partial. Thaw ranadas mads to be learned nmudfclg the totiidty of m uy ^emhae^wnwmsmiM^wrmmmvmmba i^n|o aUw^a^ma^kmwivvy. ^Aaen^edtt fc iamt booed that srith mow immuti aad wady that the anatrar* srifi be feand. 8a ausch gar the faw n ) pietose. Now let's take a look at so w spsadk opemrieu irsfrfing Vriritag ptammm ama camasonly ased caa bo divided fats thtee types, arc, gas, end mrismwm. The safety aMMoras per taining to dothtag, gaggi. and hcfcacts are ef enwmon kaosriadgt aad ihenritm, shell net he mialtaeaf hi this dhaaded. sted dom not prodnm e coeMfltion srihich Is considered hanwhd to the adder provided h is aecompllshrd la a coatpamtivtfy large pen aren. The hanm which nauit ham tedomg censitt swrarislty ef the oxides of imo aad oxides of mash which may comprise the supt or j--ytffg of the tsrldlog end. Serna In* tap an d o t aye f m u trim hove dried ander severe eondlrioar for hmg periods ef time. T h w m r t h p am paanmaddy dar to the ihpmltiaa af b m l u u srithia the tanga, bat k hm am b e u dmmwrmed dm thw^h^lM^ei^aeamdty ha dhadu bp bpdha bring tl nodal Them h t u and V ia / braring flama, s o w am lao to M o f o^oideno y cssapoaadk and fades (ram i b e n hnatte to produce rigo! latina, glneridm bs general t with mapidem stasa they msi tal ericas upon the bone v of e g mg. per cubic meter for fluorides, but no to sgroed upon. M ni ;- J tempt so keep tl order to be ebsoluxt* age docs noe ornar Sii sur adder is cu Boya mod la -- vary ta (esopei canees contata a ta in n r i d M qua hararid. Al presea . pet a t >.ux h a f aa am ar The f e a The (MM I ham l> width have been ranted wv eerie! as had. ' canse batmtal *. , fla w or ef the aie " IH MVBPBm Uwfdar|iJl th e e f load hi safhdeoe period , n w ahmeyataa and i ttagec mhflng of s a da a ef ao dm em erita'*' STM ' 1M M h | af fldswu m ' m fd w ta- 'v*V'w. Antomothm and Machin* Shop Section boring tu x , w oe metals. require fluxes dhcMafan atwdated with metal terne lever containing significant quantities of fluoride may result tom auch an expotore. ;v;4$$y compounds and (m m bum time fluxes bane 4 ^ .Vi been toow> 10 yrnrtiirr jignUtant M ttl inf* tation. fluorides in general art k obd upon l'l with stupid tin they may produce harm* ful cfleas upon the bone structure. A limit ot a. mg. per cubic meter bat been suggested far fluorides. bdtf ao standard bat been \.,*i;,M agreed upon. M ot iteduattial hygienist at tempt to keep them as low at practicable in order to be absolutely certain that bom dam age does not occur among the workers. ' r..r Silver aolder it 'ear of the taoae common Where aranamed the control of welding fumea Is generally accomplished by providing a mortificai vemflmfaa ryttem. Tbe type of ventilation uted h dependent upon the na ture of the welding. When the obfeet to be welded h petitioned in fixture or jig it is possible lo obtain effective cootrol of tbe lmes by the me ef a grill side hood, or flexible duct near tbe source of teme. If the putts are large and it Is necmaary to wdd mote than a foot bum a fixed point it h dhficnlt to obtain pod control of the team i , vl r` ? ahoys uted ia brashtg. Solders of tbit type vary in rompnrttisw and may in some in tone twain cadsaium which if sulatfllred in aamefent harmful. At ia uanriilaiwl so be the with ramoneble air volam through sys tem utiug fienaie daet*. Sfece the eflaaive mage of me flesflde doc h approximately S inch tom thd duct opening; it' h swornubunuwyv Cmaer tumfe^^*nvcAdtf M^mr nu^Mmew# w*mb^m6r udwvu^^cs^ta w^h^^ausaum*^ a terne lu air b I mWWgrwn per to lbe are is outside thb nanfe. The prue- cubic ] >e of air. rank h that most due are nesmtifly g u t, or butt sd d ia f ef piala net morod and the veafflatlon system do sw i u of ao mount tom tha physiological net wamst the team* wbeattbenatod. Ac- ifinwpnmi i n m n n n g n m m b tmdiwg to nmens thb type of tywan has opewrlom g tm d y are earned by tbe sob- haun effiertfsevy need its tUpyuda tee' the tiliaed 0 which has omm open the mesa] S'M l a ^ ^ 1 ! b ^ p M t o e r <lt should thro^ as a tese be a saHstertnry mourn ef mtiaM firn preventive. The preceding t tim ten d e s t i Is euam ryS I admise. that dm wfctta 'item' cither which bom bati teriah at lend, flamr or of Ho ef she Ihdp to flflw c the feme which ~|IPt W LSrWomMblQuwg ffMMW--mm. them metah. I M I piate other tote qwmdtim of tod to tipo ef h o i tema, period of Mtml.lt the urnof per-: ring or r Pr M I WWHg 1 merthemd as the mane 'ef dmth m a nannte ef i memo war entriti The In a Welding el eftiW i MfllMy '4N M rtSeii heiwaptfaet ai it h um Iih l ediloa of the work ea rn to J ? CAni i n f "1'ht Im i I y ? i/'i i " ..?*> 3 ,,iHk fciftti I IV . <1 u IO 3StM N ational Sa fety Congrats, 1947 grinding a( mmimk m u b which at free of and )t generally cnmtdt red a notoanm and to not harmful per at. Despite ibto Ian n w Male Inara require griding operation to be ventilaiod. Thto requirement ha* probably been a hold over from the day when andone atneb a m prevalent and aho to pre vent the emutoo of a autoancc condition. Grinding arheeb in me in induatry have ar tificial abeaaivm audi at ahunianm oxide or ailicon carbide. Emery, which to a natural product enmpoaed of eaaentially atuminum and the magnetic oxide of iron, may alao be used. A puralmibk limit ot go million parikka per cubic foot of ait for ahmdnum oxide and tiHccn carbide wa* recently ac cepted by the memberi of the American Con ference of Governmenial Indottrial Hygien ists. Such a limit to liberal and conctnirationa of cuch magnitude are normally not en countered- When lead, silica. oe aome simitar toxic material cooks in contact with the grinding wheel the expotore to the abrasive matter may be ignored and the expmute evaluated on the h ah of the toxic material. If thto latter material is controlled the nutoance trill also be eliminated. Ventilation m te n t for grinding wbceto have been b itty well standardized and gen erally ate aadritoaory to prevent a a d n a ta Hotda afamid eudme .the wheel m completefy at It praetkabie. A ir volomc thould be peovided which are tuSdcnt to cause an inward Sow into the hood when using the tnullest wheel. Thto it especially true when oak material are involved. Wtt Grinding-Bdfies, bootK and guard are generally located near wet grinding wheel to pr event dispenion of the liquid uted at a coolant. Them ( N t j n usually ndfirient to control the fia t if it to nootoxk in nature. If the do liberated h toxic mechankal e ih -- ventiiatioa may be required. Buffing and faUthing-The Inrthig com pound applied to wheel used for h n fiiq and pcdhMng vary in compcshioa. Waxes and various type o f abrasive are the major component. These material plot Uni and fiber born the wheel are the cmmtlal In gredieott o f the airborne dust. The toxicity to dependent upon the type of abrasive. Generally ventilation to provided to at to improve hooariteeping and redace the num ber o f nmpbiact and n o t'b eam * of the baxard to health. . MaekM ng Smoho bom oily port* to the prevailing towoa of air amtaotinadon at machining operalam. Ulnow hat ivd been attributed to thto typo of exposure. At It the cate with ino rumo and duna of (he )tao variety little to known to what ef fect tuch materiato bare on already storing physical abnormalities. Machining operation on large chip or turnings; oafuequtotJy. e to net a problem. Opanriom totvofvlng the tnacbtelag of high lead alloy* have tidied. and rigattm at quamiftot of ak- borne lead have not been demoonrated. Graphite which beam abbona doting the machining of mat toon to not mmideeari to be physiologically significant, and there fore la ctaatted at a trattarne dote Frequent ly management w oridew to advhohfr in pro vide vcndlaitom for the; maditola whkfi at* productiva of the the dothing and fMKhtenr Is Ventflaitom tywetm for the machtotoog, d rift ing, and to forth, of c m toon tbnold ( dhada boodk located a nenr (he unita d ril* aa It penritotoUe. Many of at* tot w a oa peodualon mochn doing an exttflent job. of drat AbrntitM f h t t h if l i r tifici I niaed m the aao hanafnl of adnecal MIMIMI WybMwmmVfi ait the itone o f ImMBadan o f canamerriaDy bnik Band Mnai ago lp a *. Gantionoot mage and laefi o f matoatenance noth in a ture*down o f adequate cruwral. Yfadbte m ope of da to the best rvidenat that thto bm occurvad and ft to advisable a otiw t such a mndbian widtont tandee defary. Employee* who aw watieoed in b b a teman are dependent open pus m al t t y jt u o y eydptueat. It I o f u o m impottaatc th e such devimi are o tn type which wfli peoride the it-- ari puatrtifcio Devices c f thto type arc of the tuppMedoir variety.and it to naces- tary that the air provided be bee of harmful nonttmlnaiwt T h e air mrapramm* thauld be locaied In an an a bee o f rtmtnrrmitin otherwit* theoantam lnaatwfli bo tcammfewd to rim beton and the breathing tone o f the worker. Normally, ventilation within the room ft prvida) to at to improve vteibOitv and to help prevent the amp* of d w t la A t am* founding u r n not to reduce ih t amonara* rion o f tflka da in a tale k v e i Tumida or U t e uni use ventilatoo 10 pre 4. Leakage d be renttint. fornii sand Ida tor cowcttdr rim cabinet, fraquev dy he dot or the ' tom. The f a u Mm rittougb (h i (irovtowtoy to rim * ptoyet and tot an, Mtoeftde tomi for # be mete* qusrad to ww io y u M-atoHI--fCithPoeDtfi--JrKi-nd o 9 bota grites dr tte aofnnae mtt., ' mainteuame af mw> htaMMSg, d d u i| t ri vo n tweuorv as lor Tbr ore of eri > m o S at tape tuag, I k , , rittm pamkka 1 oMtoam tot mu that -operatimi ___ abusive rriSoea toditod1 that oaderof t and eaqube____ Jog gaad co- TM1* *" the vapor that leakage af mu J Aeiomothe and Machine Shop Section Il -jtt iv the mir ton at iv i* ( b ttn o. c \ |n irt. A* i the ' 'si of rhe nui u> vh at riradv n in rn g Tumbln or rotating table type of and UUm units thouId be provided with uifheient ventilation to prevent the ncape of ili dust Leakage due to eu M iv t Wear should tie remedied. Small und btaM a h in m . where the opera tor conirol> ihe tdaM notile* from outside thc Practically all inchntrial plana bare operalion* w hich involve the ue o f leadin g h u e tearing metal or tedder. Babbitt bearing metal containing approximately 7$ per cent lead h a been encountered. The composi tion of soldier metal la rariabie and de' pendent upon the purpose lor which it is labinet. frequently have lauti teak around uied, with ordinary aoft solder containing a o . I produce ibe done or the rubber gauntlet are kwve comparatively high percentage of lead. - u c fii:* . dint oiving ih c <e torn The dutt which ape Iimr the ibind through th o r upnvtnav r* in cio Assuming that ibe babbitt or solder in roe ia one containing a significant amount of have been iiici of lit Itotimiiy to the h m ik in i nine of tlie ern (-knee and in many inviarne* retted the per lead, the questkm then .arises as to whether or not the employees working with this ma rMI'J'.ol mieviMe limit foe ilka. TW leakage hotikl terial will become ill. The answer to such a rbum t dtm ng le termed and (he men hnuld not lie re question could be given by a qualified in ' axiu d rm t gutted to roe rapinatori. dustrial hygienist a lia be had teen the opera . r*t thrrr II the artklei being bU*ted are free of tion and cwaaldtred such factor a the tem -I. Feijuetw ilica or other toxic material, the (hw raub- perature to which the metal it heated, the bk io pre- ing from grit or aim Matting i* c M M in amthod of removing n o a s solder, the length bine Iw ti l i t he nutunce categorv It follow* that the of exposure, and the cfiecthtnew of the con 'raf*bie an 1 maintenance of entilatine (no- for grit trol measure provided. tnsxim tinx I bUuinit. although rfeslrshlr h tvw alwav It is a weft known Can that lead causes c n ifiljm li I n t m u it a* for a n d Muting. illnew if absorbed in esmuive amounts, and tmiR Still ,m u i >4iukl in (he ue of ect gut ot hot h< Maying mom produce excexuvely high morentia therefor operation* wherein lead weed have recefvud considerable attention and < i* u m ii.w of <hnt wilMn the emfontre It ia there Mody. Om of this experience certain prac ih r hmrb ninrnr and i r ime. nerenanr to protect the worlrr within the room. The remadm i a d a M in the are- tice* are known to produce exemei ve exposure iiw iw omci p n a m vv o n p n m not 1 cuouof tK-n deroted to and Masting me a t ate their- to be harmful. It is generally conceded that -.n a i- it t o j fmr. pettinewt when considering roemi in excoaive cowcentratforo do not remit from >if M n r u t 4 m , rtNBlU hidt cri grit t f A m ate road a* the shea- operathwt where solder is applied by means n m i of nm- liw . Vapor Masting, a aria*ion of ami Matting. of an electric soldering iron, Tbia Is |>robably due so the smalt amounts of scMer used and ipm enl. G m xtuncc trmlt of comparatively m em devefopoewt. Thh the cam panthcly lew heat o f f i t aaetat. i-ik u ic rontnal Vinihle l r o h m inreHet the roe of (hie lica and When an iron b roed wbkh It heated In a t b it tht atrr under premure. The tiUca w n l in vapor mall gm find furnace, the expamre amy be .A t v n m i Mum unit uria in d a and may even be a IR |^IUIU CB W ^IK M t. OOMKI WTUCo Itn ttJ fll vaH aa ity s medi (approximate! to a t on the iron earning lino contact with the deLv iron*) It m genemBy bettered th a airbmne cam or heat It vulactaMe lav olatflintfon. M i n o tro dica partkJe below $ aitiniw a a tnotf if- Sasall ameuno of tokler drop from the bon R fltltM ) m icaat in o M itg tllfaal. h then follow onto the bet Moot of the faraace where it b tarne tha I I hat operatimi iwrolhig the a e of d ie t readily skatAired or nidiard T h e oxidised a ita tile whoa initial paatkle a ia apprenda* saatcrial amy became airborne dwe to dfe- f :hn tvpe that tmfcr of aagwltwde a a a a e huanlM t, lurbanm created by the flame or by w arn.- J d ti nere* and ra p ita a t ia it l rigilancr in aainuin- Hag or ptadng the soldering iron in the fur .er of h ir n la l be (pond cd*m nI. It ia, (h ra fo a . e a ta tiil that the vapor Maw cabinet be maintained ao nace. Fttqucotly industrial hygienists recom mend that ventilation he provided far heating ata mlton that irkjgr of he doe* not ocrur. Ciood writ o f thh type thenTOy removi ng lead >in iM itttil hom ekaping la ala anential a piSagr of Mate* and dutt from the environment. This mh o f th e the an d and water hadgr p ai the lorn is punkularty true in small roouw or where di m a a mette tor urn dharmlnaifon many ends are in use. ih* t'mm i* f a the w aar evaporate. Likrvfce, cen- The ataaespherfe conumlnation n r n ih in r il ind to td n m et the dried nudge howld not he a l by the roe of either gs c* electrkaliy honed tut w ih r tro V /mantra- u <e*H. lowed to and fn the factor* where they can he influenced by air curirnt of high M taJfy. pens containtag solder it dependent mi a nundm of betun. With highrr lem pennim mote mlatitUaMon will occur and the greater H lh Xational Safety Congress, 1947 wit! be the exposure. With the higher tem perature the metaf U more readily oxidized to produce a dross consisting of a high |CTttwage of lead oxide. The drota may provide a protective coating to reduce the volatilization of the lead: however, diiturbance of this coat ing Hill create an exposure. As a safeguard against excessive contamination. pots contain ing wilder or babbitt are usually ventilated. Where cr possible it is advisable to enclose the jx>t as completely as possible and provide sufficient air volume to overcome the thermal effeetj of the molten metal. Attempts have been nude to uve natural draft ventilation system* to control there fumes and in those instances where the- ducts were not of suffi cient diameter the system was inadequate A preferable method is the tire of mechanical stems. The removal of excess wilder with power driven tools, such as grinding wheels, discs, or wire wheels, creates airborne dust which mav contaminate large areas of the factory if the operation is extensive. Diligent use of abrasive cloth will also result in excessive concentrations of lead dust. Filing, however, is not productive of small particles and is preferred over the ore of power driven tools. If filing i< not practicable or feasible it will lie necessatv to provide some fvpo of me chanical ventilation system (or the solder re moval operations involving the use of power tools. Since the jiermissilile limit generally accepted for lead is 1.5 milligrams per to cubic meters of air 1555 cubic feet) it will he necessary to have an effective svstem to provole adequate control. F.nginccrv experienced in designing ventilation stems to control toxic materials should he consulted, other wise a ccwtlv svstem might lie erected and later discovered to he entirely ineffective. Fre quently solder removal operations requite the use of portable tools on Urge objects and a local exhaust svstem would not be effective, a* is the care in the fabrication of automobile Indies. General contamination of the factory with lead dust has been eliminated by enefos ing the entire operation in a Urge booth and exhausting a sufficient quantity of air from the enclosure to insure a constant inward flow of air from the factory into the booth. I'nder these circumstances no practical amount of air could be removed from the Inoth to reduce the lead concentration to a safe level, and therefore it is necessary that the men working therein he provided with adequate personal protective devices. Heat Treating--High temperature* re a frequent source of complaint from employees in heat treat departments but such condi tion* and their control are not within the subject matter under discussion. Fumes disseminated from cyanide | t are often associated with cyanides used as fumi gants or a* the lethal agent in death cham ber* and supervision a* well as the employee becomes apprehensive. Fame* from such a source are irritating and because of this property should be adequately ventilated. The irritant nature of the fame is caused bv alkali formed upon decomposition of the cyanide. Molten lead is sometimes used as a harden ing medium for metals. Frequently chattnal or m a t similar material is placed on the surface of the metal to conserve heat and prevent oxidation. A covering of this tvpe reduces the volatilisation of lead while the bath is quiescent, but has no effect while the bath is in use. Adequate ventilation should therefore be provided for baths of this type As complete an enclosure as is practical for the operation being performed is advisable with air quantities dependent upon the open areas In the hood. T o prevent contamination resulting from volatilization of lead accumu lating in the combustion chambers the prod nets of combustion from gas fired lead pot should be vented to the outdoon and not be allowed to dissipate into the workroom Iron Foundries--The principal ingredients of foundry dusts ate silica, sea coal, days, and parting compounds. The predominant ma terial will be dependent upon which phase of the foundry operation is being studied and what operation is bring performed. The control of dust is the major problem, whereas fume it of secondary importance. A discussion of all the aspens of the in dustrial hygiene problems in such plants would require a separate treatise For the present discussion it shortId be wiflkimt to state that all obvious sourres of dust di* persion should be reduced to a minimum by adequate localized exhaust systems. In a mechanized foundry such places would be sand conditioning and mixing equipment, tumbling mills, shakeouts, cote removal and knockout stations, transfer point* of dry sand, abrasive blasting operations, and all grinding operations performed on castings containing appreciable quantities of sand. Maintenance of scuta a major item in foundryabrasive action of the dr that a good program be m keep the equipment functfo riiriency. Because of the heat ano wale foundry activities > 10 see pedestal fan* retted in such a manner drafts which interfere moval of the dust dh tion in the placement will go far in red in the areas where they a> After the obvious has advisable that a survrv <,. made by an industrial hvgi. accurate evaluation of the r obtained. Retpirnton Protecti.* Iwm Mated, the atnynp of dust and fume and o' he reduced to a safe l* haust vent ila1ion m ve to correct the condition lew toxic material. If practical respirator? Iw used. The? may also riving protection durin provide protection for inter or to mpplemrnt other r The? should, however, not the desirable means of am? hazard. Med-1 The complete finishing of troptaUng may include: t. Cleaning by abrasive*. *. Polishing the base r 3- Cleaning with solve 4* Cleaning r 1*1 5* Cleaning w. "Pickling." Metal deposit' 7- BufKng the dej 9. Lacquering tbIn abrasive d -iigh temperatures are a complaint Irom employees went* but such cotvdi .ol are not witliin the tiler Jbcuwion, 1 from r>anitie tots are m o in td n used as furni' si agent in death chant as well as the employee sc. Fumes Irom such a ! and because of this . adequately vtntilated. f of the fume b a iin d >n decomposition of the dimes used as a hardentetals. Fnquentls charcoal material is placed on the 1 to conserve heat and A covering of this ivpe ation of lead while the it ha< no effect while the 'equate sentilation should * for baths of this type insure as Is practical for y performed is advisable ,pendent upon the open To prevent contamination tiliation of lead accumu don chamber* the prod ;rom gas fired lead pots the outdoors and not into the workroom. ' ' -- :i;:ncipal ingredient* ci coal, clays, and ; icifominam tna in which phase ' l<rnp studies! - rrfcirroed. The Mem. whereas 'r > i i - ts I the in i s.i.h plants o i r r - i --- For the . - .1. ! : i<r `lioetu to .* vi tircr^ u( lust db .1' n l In a in i uriMim by f -jus vsteirv III a v niil pturv *.<M he i :.d n m -tig I ' p r p t u fit takeouts. core trutoval .u.d rransfrr points of dts ''"liftg operation*. and all wr formed oo castings '.* ijiiantiiies of tin l. I AutomoHvt and Machine Shop Section ii Maintenance of ventilation equipment is a major item in foundries because of the abrasive action of the dust. It b imperative that a good program be maintained no as to keep the equipment functioning at maximum efficiency. Because of the heat asrodated with large scale foundry activities it is a common tight to see pedestal fans or air coding ducts di rected in such a manner as to create cross drafts which interfere with the eftcient re moval of the dust dispersion. Better discre tion in the placement of these tans or ducts will go far in reducing dust concentrations in the areas where they are used. After the obvious has been corrected, it b advisable that a survey of the foundry be made hr an industrial hvgienbt so that an acr-urate evaluation of the exposure may be obtained. Respiretorr Protective Devices -- As has been stated, the atmospheric concentration of dust and fume and other materials may be reduced to a safe level by adequate ex haust ventilation. In some cues it b pomible to correct the condition by substituting a less toxic material. If these tummies are not practical respiratory protective devices may be used. Thev may also prove valuable in riving protection during an emergency or to provide protection for intermittent repomres or to supplement other methods of eomrol. They should, however, not be coswldered at the desirable mean* of controOfng a health hiatrd. Experience hat shown that frequently pro tective devices have bom issued which do not provide adequate protection. Upon inquiry information was generally offered that the safety engineer was not too well informed as in what should have been provided. The U. S. Bureau of Mines at their experi mental station in Pittsburgh tests equipment of thb type and studies the protection of fered to tlte wearer. If the device b satisfac tory in performance, they issue an approval number tci the manufacturer which appears on the device as ell as the container in which it is rereived from the manufacturers. The approval granted by the Bureau also stipulates that type t f materials for which it b approved. It has become general practice in the field of industrial hygiene to recommend the use of only those respirators which have been ap proved by the Bureau. Safety engineer* should likewise insist that such devices be procured and acquaint themselves srifh the type of protection afforded by each device and thereby provide adequate control for the individual wearing thy equipment. Some en gineers prefer to stock only that type of res pirator which will protect against the more harmful dims or fumes, since a respirator of thb type will also give adequate protection for materials of lower toxidtv The advan tage of such a procedure ha merit at b re duces the type* of devices needed hi ode and likewise insures the correct device for the more serious exposures. Mated dooming By THOMAS MOONEY Med-Fac InduMrial Hygteoff Laboratori The complete tabbing of metab by elec troplating may trvdodr t. Cleaning by abrasive*, a. Potbhlng the base metab. j. Cleaning with solvents. 4. Cleaning with alkaline solution1. 5. Cleaning with add* often referred to as -fjdL lin f." 0. Metal deposition or electroplating. 7. Buflfog the deposits. A. Lacquering the finbhed product. 1 abradve droning, road or Mad shoe is used under presatire. The potential health hazardv in thb type o f cleaning are exposure to tto t of a high free silica (SO J content caused by the sand and aim la metallic dust* where metab capable o f produdng toxic dusts are cleaned by shot arm sand Masting. Steel shot blasting h a much km revere health hamrd than sand Matting; cutaeqaeMly. red shot abrasive dcnttlng reethofh should he used wherever possible. The maxiamro altorahle coocanirreloea (M AC.) for In c siika are fire arillloa parti- y 'V ! ' ~A