Document gr09RVNBB50G4by56nG6B3ka

CONTROL or ail PiBir.5 IK UDbsThl C. J. fcConnsll, k.D. Acsistmt J-.cdicai Director Director, Industrial Health Bureau The extant of oust control roquireu for any particular plant ares is aotormincd by the f reaominutir.,; action of tue contaminating dust or mixtures of oust on the bony emu tue severity of oust ex.-osure. The *i2e of tut ^trtic-e* of bust result!ng from tut bruiuc ao*n or disintegration of solid materials through physical or mechanical ceane range fro*. particles visible t. toe eye uoss to microscopic ur.c sob-microscopic dimensions. Very often it is t.i.t invisible bust that c-Uaes tuc cost num. Toe particulate matt-c of fumes end emote crested by processes such u burning,' suoiiiotior., tnc. tuo refaction of guses to form solids is usuui--y less t-.un one micron is size. The concentration of oust particles dispersed tithin the breathing cone of '.orders is determined wherever joseible by stunbird sir sum,linf rrocodures, since not ail aethoos are equally trustworthy. The better trained tl:s industrial engineer or enemist the more r-iiablk tut results. The analyses of sample* vary derending upon t--. nature oi tue itteriais an- tut information dasirec. Tbs fibrosis-producing custs, for example, are cstormined by.a prescribed teermi;ue ar.a txpres-ed as numb.r, size, &r.c composition in a unit quantity o* air. Ir. sumo speci-1 in-tancs* t..e amount of uust is aeterminee gravinetrical_y. Quantities of moot of the otn^r air-borne o-sts are general-}- exrrc-u&ed or. a eeifbt-volrae basis. Caere indicated, chemical arid spectrogra.-hic methcae of analyses are used. Air contaminants usually eatjr tuc boegr through the ras.iratcry tr.ct. Ingo-tion end absorption through the smin are less iar-ortunt portals. Sot all dust* in concentrations uju 1 iy ec countered lx incustry are - harmful. ooce ir physiologically in=rt u: lie free, others nay be eoccp- suaated in too tissues, or nay be absorbed xitucut j rouucfng any ncticutble effects, usts, sued as Caroon ana iron oxiae, arc beiifevsa to rutaru t-.u unset *na uooify t..e prcgrss.* cf silicosis. Linostcne u; Luraic arc cxaapifc., of c-ats aoich cause no injurious effects. Eoxevcr, hamleau waits ir. hit-r. concen trations nay be- of a nulsasoe nature ana should bo kept to a uininun. Of tne haruful variety of ousts sane exert their effects locally on the sain, auc..w neabraaec, e-njunctiv*, teeth, anc through irritation to tne up^er roapiratcry pas-agos. i any organic dusts ,roduce al.ergic rcacticr.o in ser.ol- tixec persons vith resulting as ton*., rhinitis, an- eth=r oisturueneos. An iir- .ert-r.t group of dusts mlieh arc lrolnals or only sclutue vita eirLcuity In tr.e body fluids initiate fibrous enangea in tue lung tissues. T-eoc are United, so far as *e hlvs evidence, to a fev of tne inorganic i.inrul ousts, such oa silica anc asbestos. An equally important grou4. of dusts union arc aclucile or slightly soludse in tne body fluids an* indirectly toxic mnon innuloo, ingested, or otu6rise ahsorboo. lead, aanganese, areenie anc tucir coupu-nis arc cia...c;. Inc-Uued anon*, tat aunts of tsis group are thcas t.i.cb nay In irritant at te_u as toxic, as for ex*a,.lv tis explosive TliT frinitrophenol, ar.a picric acid, i lifts oTocp of austs causing increasing concern art tiiias ari-in; ir-a r^dio- uct-Te cren. Tut cuagnosis cf any barefui cfloots tc tr.s veraer fcij'O r*c; dusts i- entirely a medical problem. anc. is bused upon a correlation cf t_i ..atient's occupation, syuptons, u.u physic-1 findings, i-beratory ano i-r-y e:_uin_tiins sai^t be include- men indented.. The p-eri.de n.u-tu bs_i.iaatim offers tui tost efiectirr- t*-uns of liseor-r-nL early net only tua occupational aisea.se> or intoxication^ but also serves to check tr.e adequacy of preventive Leisures designed to prevent hai&fu- substmoea free escaping into to..- breathing tone of workers. It is in,,oruent for tae physician to fa:. ijjarlze r.last if rith ev.-ry riant frocoss m- ritn thv cutoriais used in tuo pl_nt so tout bo t.ty ap praise the workers' surro-ndings. A basic consideration in forcuiating t program of dust control euut meet optrational requirecants is cell is rrovf.de protection fr tnudum number cf workers. The first thought in prevention should be given to the poj.ibility of sub stituting hanalesa or les* h^nufui substances for harmful onvs v^erc tuero will be nc interference wlta t..= quality of tuo product. Typical inst-nces of suc cessful substitution include tuo adoption ci c.onsiliceous parting compound. in fo.nary practice, of steel snot or grit in plaeo of sand in hint-cleaning operations, mi of artificial tertsive grinding me. polishing wheels for sand stone whssis. Tusre substitution is not j ncticil various engineering u.t-.ou.^ my u. usod. It is, of course, preferable for plant nanagamont V. consult u.. engine.-r before tue plant is built or remodeled so tu_t control features cu. ou tnginevrjd it. v,, t v plant inu aacnir.ery. locis uachice manufacturers new include coitici equip ment is an integral part o. naclones known to produce or disperse a-sti. Cperational cn_r.ge_ or a quango in the ; roces* to eliminate specific uazaraous aspects should be c~r.sid.tvd. Conversion of ..and opvoutions to partial o; lull mechanisation up be .os.ible. hechanicol hand.mg and renote cou~.ro! cf dust-creating operations frequently permit teiu use of norm camplet- enciiourc and ventilation a, plic.tion as well as turn removal cf tuc ~.order iron zonss of highest o_st concentrations, ociuor.ng .i-occases toy sometimes be c:-an.gi>d U welding, tin.- eliminating l--_a fumes one oust. 4 Segregation of dusty processs* uy be used to sdvantige. There plant layout sna operational procedure i- designee to remit separate bousing or isolated ioc.tion* for aust-rroaucin,; operations, particularly U.cse difficult to control, tuc exj-ojure is limited to the least Btcbor of e&riCers. 7;.i* can souctiues be aceocplisbec by arranging the forking or production schedules to penult postyoneuent of highly austy processes until tn* esc 01 the shift or j.rlr,ciptl eoritlr.g reriod. Ini* letter procedure is conuonly usea in t:.e case of rocubiaoting operations, shakeout unc sana-eor.uitioninj tori: in founary practice, "his has tac. advantage of either siUj.lifying required ventilation teaeures or Uniting need for personal respiratory u^uiptent us *eia to of reauciug the. osod nunb.r of torsers. T;.i onclosur. or total enctsercnt of dust-,.rouucii;g units, sucb as conveyor bjlts, cress ano elevt-tors, vibrating screens, grinaln. nills anu bagging aachines, is effective in greatly reducing duet diversions. In up.lic.tion of teener.! cul exiituet to tno enclosures uiia further aocruuse t:it escape of aust iron these sources* It is sonetines possible to abate aust dispersions sufficiently by v.et octoons, sues *-s s,ruy or street of ester cr by t..s use of fou.a, cclloiat -u.a other setting agents. Tneir value, toeev-sr, is liiitea enn *r.o'.tla *i*tys be checked by oust counts is tuo adjacent ureathing tones. 7ht tc-t preferred s*i.t*.c nstn&i of csntrcllir.* oust dlu .r.'.i;n it-- by effective ventilation. by effective, I neun a ventilation cystet that is assigned to o 'Ei'orc vitn established engineering ^rincip.&s txa reco(y.i;.ed goon practice. It tolxoas, also, tc.t eaocust* cure shoulo bo observed in its use. er<c tsinirnurce. Tnc basic criterion in W aes.^ oi Ventilation c.susur. s cr iec:v.nicsl exrxuot systems is the preauction of til current, tt t-.c. point of uu.t gone ration it a rate Vhich rill destroy tnc energy of tuc esct.in* dual arc farce it into -5- t;.e txn--out ijBteCf tnerxby reducing dust concentrations to *itJ.in safe licit... An efficient exu.ua t ayotcu yruouces uou^unte uir velocities nitc cinitUB poser cs.-n.uuc;;lion In tnu uro- of au-t , rooucticn tnj c. uinicuc ulr i'loi froc tnv oust fre. cross. An cjcn-uct syetsu s.-usuXd to eijuip, -a riU: u suit-bie Woou to er.c.o-e -s cucL i.b .oaoinis the- e.urcu* of u-t -rocuction una tv , twine u.r velocities sufficient to ut-t. t-e .urtici.es lute the cxnvuut systen. lnoo_. it i,, ;r-ct-e-olc to uis.-vuo c: t_u. .t into tuc outuiao >.tuosrh.ref tuc sy..tuc t_-iso o. c.uip. cu tit., u au.t collector 0: t.-.-s.a of i'iitr-tiuc. T-.re t... cuts!_-t-.i-- . t;r i. u--a for uio;-s-it . rvc_tion-ry ue-jur... uh-uitu us t-uer. to ; rcvu.t .u_.iu-o racircui-tien or re-entry of u.: .nt.- .i.-t-v tut.y. o on v*. c: ctUt-r Dw_nu of ncc*so. Obviously, tec.nl<u.i er<^.B.orinu jmou_vube uu- on eriunco sr. nt--entiu- to uesvgn sn exi.us.jt s,. a tec tr_t dii ua..u_t*u.. ecu . t-cl or elldi-cte suut uisy-rsion* of opor_ti-i.u yrocucinu a-ut, Coou bcner-- ventilution or- dilution v-r.tiiution of v0.^..co. i- o; ter. -uf.icisct it' t-- r-te o; uu-t crouucti.cn is not c--cts--re. 1 acre j_ u. v>.lu_cs .f _v r ure e_ ioyeci o.ru cu_t Ur tn-uc to -v-I. uiues.r-lu.c ur-itu. Gun.; venti--tiur. uy neon_nic_l cuh_ust oousur.o aio.io<.riy rev-urci <.. coruful ctveo' 0. tu . rou-au ir. cr-.r to u. ful.y ef.active. . rir.civui i_:tcr. inciuj* aueruute .ir covcc-nt ut tin. points of ti^htst dust concur:tr_tier., on- -iuvo ulr o-or to tns sourcec of cxiivnut* o.u;rt c. rcuitinj of -ir fiat is u cos-on .uiuir.r. t:-s _*tiU.-_ of coctroi* Teutii-tion c.t-oorcu t-no u;u_UHt s. ito_u, ucvtvsr o..'ici_r.t T...on .'.r.t ; .u.-it u; t to a-.t.risruto or U* nijuood. Ai. sue- <e..uiro_nt r^ul: ss cori- etur.t cusCuic.; nu uuinto-n_-.ee. It io not uncooo.on to fir.- t%x. ii.jtul-cuior.t o: uu.t controo e..uipcor.t runu-oro* uur- or -to. u.soe-- oy c6C.u--.ic_i uelwts o:- oy li.-iLJ..'. !nM on to.- ; _;*t of t-.- voru-rs* Tc. efficiency o; uu^t c:------ ut syatuuo 6- - tac other nethoae of forced ventilation should be cheated ty t.eur.s oi air san-les tenen by u1 e. ...roved tec.uiique. Tnie shouic be don* r.en tu.c s/stec 1b first installed ecu ,riodicoily t-.ireufttr. bno.r purticui_r circumstances respirators ana other respiratory protective e^uipccnt vom b,,. the ir.uiviouul torlcr iiu.y provide sufficient protection against casts. Tub sinplest type is t.*s lueenani eel-filter respin-tor tnich reuevts a varying acount of a particulate contaminant from th air passing through it. Tae b-.tter tr.e filter cu-terisi tnu hijaor tu.s .ercentege cf oust re.'.ov-jd. Only filters proved by t:.o Uj. bureau of bir.Oj far different mines cf uost3 ei'.ouiu bo used, are intenaeu for ejc-osureu ci short duration ur.o net for continuous use. Ice supplied-air respirator tith helmet is used x-rgeiy in operations there t..~- p_rtici.s cay injure tr.e *uc* ana ey*s, even to sju;dtlaot.r.f u.u a.-tal grinding. It is essential that tai tyt; of respirator Oe proviaeci witr. an adequate air su.._ly aratn from a , ure, cust-irce source. Tne nistaae is aoi-etib.es made of taxing the air directly fron. a compressed sir line titheut providing the air in tern. to compressors vita a filter ca-tbl* of reuoving tat fir.* oast particles. ; er:iaps tat -ir of t-.c compressed air lino aay be set &nu oily jiving rise to C'.ora t-r.a even in instances v.er-. act compressors v.rtial_y aec-a; use t:.t oil t: car dor s.onoaiae gas &r.u ofnor gases, h-tur^lay, under t.ru-s* conaltioos, tne air is unsuitea for use in the respirator. It t:.en becoaes necessary be ir.sta.f_ a stall ret_ry co*.. ressor or blorer vita a clean source cl air. Ini. a:ti:oa is also t,_iicable in plants net .uip..ea site cctp.ressea air, Infcrtunutely, t..en vomers sr ongagaa'in operations retiring fre.Qac to aove scout unnan.*rea b. sir nose, tat.. type of respirator cannot be tern. Inc effsetiveness of personal protective e^uipn^nt, ineiuuur.g rkSp.-ir-tur*., g.cvus, oi.f special clotting, ce.ends u,.on proper selection _r.c cc.ii.ven_r.ee. Ine education of toe turner in tneir correct use is Hatties in,urtant. -7- orderliness and cleanliness, so far as practical f*r trie type of serk car ried on, ar* important factors in oust control. For cleaning, safety, ana effici- ency, floors snould be of concrete, sooden blocns, granite, or other impervious material. There set processes are used, adequate drainage sno^la be maintained, and duel boarding on other ary surfaces on mich sorkors can st-na snoulu bo provided. In tne event tnis is not practical, ruboer boots suould be furnished, tolls, overxxead structures, ni equipment should be cleaned periocie_liy, rfer- tbly by means of & good vacuum system. Tnom possible, ana cleanir.c duou-o be aone sft-r Poncing hours sith ample protection afloraed tnose so engaged. All aaste products should be disposed of in a safe manner as often <-t neces- *_ry. Unuer management supervision a responsible person or ,arsons should b6 assigned tne tasm of supervising housekeeping conditions, elimination of bad shop practices is best accomplished by instructing formers rog<.rding mangers inc.csr.t to occupations. Tne employee *1* un..orsturids ti*e reason icr employing . rotative methods sr.o devices *ii_ in most instances cooperate ;.ith i.tjri.ge_ent in cotaiming results. Tucse general . rinciples of dust control measures tog-t.-er rith adequate medical Buv.ii-vidion of tus uorner ar* eur bast solution to tma control cl tar oust problems today* TEE MEDICAL SUPERVISION 0? WQRZSRS EXPOSES TO DUST BY W. <7. UcCOI&rElL ASSISTANT MEDICAL BISECTOR IN CHARGE 07 INDUSTRIAL HEALTH SECTION KELTASS DIVISION METROPOLITAN LIPS INSURANCE COMPANY TE3 MZPICAl SUPERVISION OF WSP.ZERS EXPOSES TO DUST by T. J. McConnell, Ji.D. The hazard resulting from certain dusty processes in industry, al ways an important problem of industrial medicine, has been given undue publicity within recent years, and the conflicting testimony of those who specialize in the litigation field has led many industrialists to consider claims of alleged disease resulting from duat exposure among the common rackets of the day. Al though many of these claims are admittedly vague and appear to be based more upon the universal desire to get something for nothing than actual injury, health impairment often follow* exposure, usually after & period of years, to certain dusts or mixtures of dusts encountered in industry. The harmfulness of dusts varies widely in accordance with the physical and chemical natures of each individual substance. Certain dusts are soluble or slightly soluble in the body fluids and their harmful effects are proportional to the toxicity of the compounds formed. Lead, mercury, and arsenic are examples of poisonous dusts. Other dusts exert their harmful effects locally on the skin and mucous membranes and through irritation to the respiratory passages. Chromic amid and alkalies are examples. Attention recently has been called to the probably harmful effect of dusts arising from radio-active ores. 1 fourth, group of dusts which are insoluble or very diffi cultly soluble in the body fluids may initiate harmful pathological lung con ditions, These nay be subdivided into non-fibrosis and fibrosiB producing dusts. 'Presented before Twenty-tniri Annual Safety Congress, Natioral Safety Council, Cleveland, Ohio, October 5 193** (37 fibrosis is merely meant the replacement of the normal elastic lung tissue 'ey an unyielding scar tissue.) Che organic dusts, mainly the vegetable fibers, such as cotton. Jute, hemp, etc., are non-fibrosis producing dusts. The fi brosis producing dusts are limited, so far as we have evidence, to a few of the inorganic mineral dusts, such as free silica, crystalline silicon, quartz, and certain combined silicates. Of the fibrosis producing dusts, those having a high percentage of free silica are admittedly the most important because ex posure over a period of yearB to such dusts distinctly predisposes the individ ual to tuberculosis. It is seldom, however, that any one of these groups of dusts occurs singly in industry. Usually we are confronted with a variety of dusts in vary ing combinations, until research investigation determines the effects of mixed dusts in measured combinations, it is difficult, if not impossible, to 0 evaluate their degrees of harmfulness. The diagnosis of a disease induced by exposure to dust is entirely a medical problem, and is based upon & correlation of the patient's occupation, his symptoms, and physical examination. Laboratory and X-ray examinations must be included when Indicated. The elimination or control of a dust hazard re quires the assistance of the engineer, the chemist, and specialists in other sciences whose training enables them to contribute additional information. It is essential to determine the source of origin of the harmful dust, its concen tration within the breathing zone of workers, its chemical composition, and ir. most instances, the particle size measurements of the dust. Kith this informa tion and a knowledge of the length of exposure, taking into consideration indi vidual susceptibility and other physical defects of certain individuals which may favor the action of dusts on or in the body, the extent of the duct hazard -3- caa be fairly well estimated. Cast determinations Indicate the locations where preventive measures =ust be applied. The effective nethod of prevention depends upon the circum stances giving rise to the hazard and may Include the segregation of the dustproducing operations, the hooding or enclosing of the operations with the appli cation of adequate exhaust ventilation, increased general ventilation, the use of protective clothing and respirators, good housekeeping, and, most important of all perhaps, the consistent maintenance of dust control equipment. The methods by which dust may be collected and studied as to its chemical content, size of particles and amount per unit volume of air, have been the cause of much investigation and research. The general procedures followed have been so ably described by previous speakers before this group that any re ference 1 nay make would merely be a repetition and a digression from the sub ject of the paper. The effectivness of dust control measures in preventing diseases produced by dusts can be determined only by careful physical examination of the workers so exposed under the guidance of cospetent medical supervision. The benefits which accrue to the employer and employee, alike, as a result of the physical examination of all applicants for employment, as well as periodical examinations of those already engaged, would indicate very careful consideration by Industry of & program for control of sidoess. Such a procedure protects the ealoyer from engaging an applicant already physically or mentally impaired who later may claim disability for a condition either not associated with employ ment or contracted during a previous employment. The applicant's physical and mental condition is established and by keeping records of his subsequent ill nesses atiA accidents, the question of responsibility for injuries end sicknesses Ju incurred during enployment need never arise. The applicant la protected from engaging in work for which he is physically ill adapted which, if undertaken, might easily bring about serious impairment of his health. For example, an applicant with an arrested tubercu losis who seeks work in certain dusty occupations, if allowed to engage in such work might readily convert an inactive tuberculosis into an active one; thereby, endangering life or at least seriously impairing the applicant's future effic iency and earning capacity. Thereat the same applicant, if assigned to a posi tion that involved no such exposure, might be expected to continue for years as a useful and productive woricaan. The examination of applicants for employ ment likewise protects those that are already ecployed from the risks of communicable diseases such as tuberculosis and various acute respiratory and other infections being introduced into their midst by a new applicant. Many of the younger individuals who seek employment hare never be fore received a thorough physical examination and consequently are unaware of the defects from which they suffer. As a result of physical examinations, many defects are located which may be removed or corrected before they have caused irreparable damage, thereby increasing the efficient of the worker and often averting definite and finally chronic diseases. Furthermore, incipient tuber culosis, unsuspected diseases of the heart, kidneys, and a host of other dis eases of a similar nature are discovered and the applicant referred for proper medical care and treatment which otherwise might have been postponed until too late. As briefly stated by that great Italian investigator and father of in dustrial medicine, Bernardino Bamazzini, "A danger forseen is half avoided, & disease known is half cured." Of even more importance than the initial physical examination of applicants Is the periodic examination and care of old employees by an indus try. Such a procedure serves to check the efficiency of preventive neasrures designed to prevent occupational diseases. It offers the most effective way of controlling the health, of large groups of workers by discovering early not only occupational diseases, but many other conditions that go undiscovered until the worker is acutely ill or becomes disabled. If the various conta gious conditions go unrecognised others become infected, thereby causing ser ious economic loss as well as endangering the health of a group of individuals. Che information obtained from physical examinations affords the medical supervisor the opportunity to make certain that employees are engaged in suitable work out of which they are getting maximum results, to correct the effects of undue exposure to harmful environmental -conditions, and generally to lessen all occupational hazards. As a public health measure, it is impos sible to over-estimate the value of such periodic examinations in establishing among employees interest in sickness prevention. ?er a long time the importance of accident prevention has been well recognized by industry. The very earliest attempts at industrial medicine consisted largely in the prevention and treatment of accidents occurring in the course of employment. 3y systematic work along educational lines and establishment of safety departments supervised by trained personnel the cccurrer.ce of serious accidents, many of which were considered as unavoidable, has been enormously reduced. The problems today that confront all industries are how to bring about a like reduction in diseases, particularly those associated with cr initiated by the so-called hazardous occupations. -6- Slace actions for damages on account of diseases due to alleged negligence of the employer are being brought with increasing frequency in the civil courts, a great cany bills have been introduced in state legislatures for the purpose of bringing certain occupational diseases under the compensation acts. At the present time considerable discussion as to the advisability of including the cost Important of the lung diseases caused by dusts, namely silicosis, under the compensation law is heard. Despite the fact that silicosis is always purely an occupational disease, none of the state workaen's compensa tion laws in the united States specify silicosis as a compensable occupational disease, with the exception of Zentucky which passed an amendment, effective June l4, 1234, permitting employers in certain industries subject to the silica dust haxard to voluntarily place themselves under the workmen's condensation act with respect to the disease silicosis. Of ths eleven states and three territories in which occupational disease is compensable, five have schedules of diseases which shall be covered, and none of these lists silicosis, so that it is definitely not compensable in those states, namely, Illinois, Minnesota, New Jersey, New Tork, and Ohio. In six states and two territories and in the District of Columbia, there is more or less general coverage for occupational diseases, and silicosis may be held cocpensable under the laws of California, Connecticut, District of Columbia, Zentucky, Massachusetts, by mutual consent of employer and employees in Missouri, and in North Dakota and Tisconsin. The governors of a few states have appointed commissions to study the methods for bringing diseases caused by certain dusts under the compensa tion act and for promoting preventive measures. Very valuable and interest- -7- lng reports have been issued by such comnissioas in the states of Pennsylvania and Massachusetts, while ITew Jersey, Illinois and Wisconsin have studied the situation intensively. The Massachusetts and Wisconsin comissions recommended regulations for the preventive measures, since the disease is already a compensable one in these states. The Massachusetts commission*s recomendations included compul sory physical examinations on entrance to certain specified hazardous employ ments and periodic examinations throughout exposure, neither of which was carried thxoufdi. The Industrial Commission of Wisconsin has developed and put into effect a code which attempts to define what constitutes a harmful concen tration of various injurious dusts and establishes a "safe limit" below which the atmosphere of workrooms must be maintained. The Pennsylvania Commission recommended a scheduled list of diseases and special provisions for the compen sation of disabled workers with strong emphasis on a medical board of control such as exists in the administration of occupational disease compensation and silicosis acts in operation throughout the British Empire. These references serve to indicate the trend of present-day thought with respect to control and diagnostic measures. Control measures cover a wide scope of conditions to be standardized, which, beside physical examinations, include methods of determining the extent of hazards; equipment designed to protect the workers;, and the elimination or control of contributing factors. These problems can be solved only by the combined experience of trained men in the various sciences. She diagnosis of the diseases resulting from exposure to industrial hazards and the extent of disability incurred obviously should be entrusted to nedical men specially qualified for this work with facilities for -8- adequate radiological examinations. Disputed cases should he re`ferred to a board conposed of trained personnel capable of coordinating the medical, radio logical, and pathological exaninations as well as the results of scientific investigations. The action of such a hoard of specialists should he final. Ihe set up of a proper program for medical control of workers exposed to dust depends upon the number of employees involved and individual plant con ditions. A series of articles under the title of "The Medical Department Manual" hy Dr. Hart Z. Tisher, being published ut present in the current numbers of "Industrial Medicine", gives a very comprehensive account of the organization, operation, and routines of a medical department. These articles no doubt will he available later in hook form and should he read hy everybody concerned in the control of industrial health hazards. Any number of instances of adequate medical supervision of workers might he listed, differing from one another in certain respects, hut all retaining the essential features of control measures. Briefly, these include: 1. The establishment of a medical department with adequate facili ties and medical personnel which has qualified in the field of industrial medi cine. A process analysis of all operations in the plant should he made and the medical supervisor should list all possible health hazards and familiarize him self with their physiological effects. If necessary, he should conduct research studies to determine the harmful effects of new substances introduced into plant processes about which little Is known. In cooperation with other departments, he should investigate the extent of the hazards and devise measures of control. 2. The routine examination of all applicants for employment. The procedure should include a detailed history of the applicant's previous illness -9- es and accidents classified under (a) diseases of childhood, (to) general in fectious diseases, (c) respiratory diseases, (d) venereal diseases, and (e) accidents and resulting physical defects. A detailed history of previous occu pations engaged in is very important. The mere statement of the type of indus try in which the applicant was engaged has slight value, If any. The exact duties performed in each occupation should toe noted and information ascertained as to the probable length of exposure to hazardous substances. After the his tory has been taken and a photograph for identification purposes made (if part of routine), the applicant should be directed to the examining room where he is instructed to remove his clothing for physical examination. This examin ation should be made as complete as is considered necessary to determine the applicant's physical condition. If the applicant has been or will be exposed to dusts which induce lung diseases, an X-ray picture of the chest is an important part of the exam ination. This part of the examination may be referred to an experienced roentgenologist, as the value of this method of diagnosis depends upon the type of pictures taken and the experience of the reader who interprets them. The examining physician also may need additional information obtained by laboratory analyses of the blood, eputuc, and urine. These aids to diagnosis should be provided or made available when desirable. 3. The rating and placement of applicants. In cooperation with the personnel department, the applicant should be rated and placed, not only on his training and past experiences, but also on his physical and mental abilities .0 fill vacancies occurring from time to tine. The record of his physical and mental examination should be the confidential property of the aeiic^I depart ment. -10- 4. Periodical physical examinations. The frequency of periodical examinations necessarily mist depend upon individual circumstances according to the need for such examinations as determined hy the supervising physician. Where physical examinations axe made for the first time, the employees of long standing should he given ample explanation of the benefits of such examinations and he given assurances that their jobs are Beeure. 5. Provision for the disabled. Employees who develop disabilities during the course of employment should be re-assigned to occupations which will not interfere with or aggravate the disability, or they should be provided for in other ways. Ho program of supervision can be effective or even endure which does not Include these essential features conducted with fairness and in good faith toward all concerned. Employees want, above all else, security of employment and any attempt to use the periodical physical examinations as & means for eliminating those who contract disabilities incident to occupation without pro viding for their needs, will meet with determined opposition. Physical disa bilities need not disqualify a man for work, but, rather, indicate the types of work he can do and not endanger himself or others, thereby prolonging his years of usefulness and adding to his enjoyment of life. kany concrete examples migit be cited of results obtained through dust control measures and constant supervision of workers. One which strikingly illustrates the value of gudh measures is the experience of the South African gold mines. During the years 1918-20 the production rate for silicosis for those who 10 years underground service amounted to about 10 per cent. The highest rate for those having 16 years service amounted to 1U.5 per cent. Dur ing the years 1920-23 th* production rate for those who had 10 years of service -11' dropped to 5 per cent -end during the year 1931-32 the rate dropped to a fraction over 1 per cent. The highest rate during the 1920-23 period amounted to a little over 7 per cent with 16 year** service and in the period 1931"32 the highest rate was about UJ per cent after IS years of service. This experience can be duplicated wherever preventive measures are effectively applied.