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UNITED STATES TREASURY DEPARTMENT *- PUBLIC HEALTH REPORTS ISSUED WKEXLY BY THE UNITED STATES PUBLIC HEALTH' SERVICE Vaunts 60 Number 1 JANUARY 4 - - - 1935 IN THIS ISSUE Effect of Asbestos Dust on the Lungs of Asbestos Workers \J The Occurence and Control of Endemic Typhus in Alabama" The Prison Educator's Viewpoint of Psychiatric Semen Deaths in Large Cities During the WeekEnded December 15 Current State and City Reports of Communicable Diaeaan QuarantmaUe and Other Diseases in Foreign Countries I Vvaktrtstt uktih) scam ooezsMMBfT raurrma omes wasanraiioKi ims ,* 0098 PUBLIC HEALTH REPORTS VOL. H JANUARY 4, 1935 NO. t ' -i \! EFFECTS OF TOE INHALATION OF ASBESTOS DOST ON THE LUNGS OF ASBESTOS WORKERS A Preliminary Study By A. J. lii.HZA, AttitlacU Medical Director, Wiiuam 3. McCohkku* Accid ent Medical Director, and 3. Wrt.UAM Fxukbl, CAmtif, Metropolitan Li/e /nrur*net Co. INTRODUCTION In 1929 tho Metropolitan Lifo Insurance C-o. was approached by officials representing the asbestos industry in the United States, who were desirous of ascertaining whether asbestos dust was an occupa tional Imzjirtl in their establishments and, if so, wluit wns tlto nature of this hazard and what should be done to prevent nr control it. About this timo sevoral articles had appeared in English medical journals describing a pneumoconiosis due to asbestos dust. While in one or two isolated instances the occurrence of this type of pneumo coniosis had boon described in American journals, the industry itself appeared to"be quite uninformod of the existence of any such occupational disease. The hazard of silica dost, with special reference to the lungs, haa long been appreciated, and a great deal of study and research has boon applied to the problem (in the metal mining and certain other industries) in Great Britain, the United St&tee, the British Do* minions, and in other countries. The nature of the effects of silica dust expressed in the term "silicosis", with the resultant extraor dinary predisposition to pulmonary tuberculosa, is well* known. These effoets have been associated with tlio inhalation of dust con taining freo silica in varying amounts. The effects upon the pul monary tissue of dusts containing combined silica--silicates--ore still a fertile field for investigation, but evidence is accumulating that certain of these dusts produce pathological results quite distinct from truo silicosis. The name "fsbestoeia." has boon applied to the pneumoconiosis caused by asbestos dust and it will be so used in this report 'Chem ically, the asbestos of commerce is a hydrated magnesium silicate ' /TxQamsting. primarily of siliea (combined sOiea) 44.1 percent mag- ';^jMsta'43 percent *&d water 13.9 percent while ferrous iron and mekel are present in small quantities. This commercial variety of nucs4* u- a (l) \ \ \ l \ 0099 v \ \ l.; \ \y H V iMWWfy 4, Wl 2 MhmUw most commonly encounterTM! is dcsignnled ns rltrymliln and is one of Iho four varieties of the niitieml serion(.inol in which it usually occurs in scums. It nlmiild ho Irorno in mind that silicosis (nnd presumably nshestosis) develops very slowly, taking from 5 to 15 nnd oven 20 or 25 years to become established. This rule of pi-ogres* is influenced uininly by Uio dosage of silica whirh the hint?' receive, mid thin donHire, in turn, di'|x'iidri iipon tiirco vnrinhlrn the ninmtnt of i;ilirn in the dust, the quantity of dust in the sir, nnd Uio length of <-\|>o:.urc. Individual idiosyncrasy might lie inrlndcd ns a fourth variable; however, littlo is known of tho variations in susceptibility in I hose exposed to dust It might well bo assumed that similar variables would influence tlio occurrence of nsbestosis. In places where asbestos is mined or fabricated in North America them docs not appear to bo present tlio clear-cut clinical picture which ia so unescapohlo in communities with a true silicosis bayard, such as hard-rock mining communities. It may be that some of tlio asbestos plants are of too recent origin for tlio typical effects of a silicate dust to become manifest, but this would not apply to tlio older, mines or to all of Uio fabricating plants. The industrial health service of Uio Metropolitan Life Insurance Co. undertook the following investigation during the period from October 1920 to January 1931, which included: 1. A study of dust conditions in asbestos mines and mills in Canada and in fabricating plants along the Atlantic Seaboard in tlio United States. 2. Physical examinations of asbestos workoro, including X-ray films. 3. A study of dust exhaust systems designed to oliminoto asbestos dust. Data on the fabricating plants only are included in this study and aro designated in the report os plants A, B, C, Dk and K. This in a preliminary report. A more extensive study of tho asbestos industry ia now under way. OUST STUDIES Apparatus and methods of sampling.--Both the impingar (1) and the electric precipitator (2) were used for the collection of air samples for dusts at the breathing levols and in close proximity to the workmen. Both of these forms of apparatus are adapted for this work, os they on transportable, easily set up and adjusted for the taking of the sir samples at the proper level, and on extremely efficient. The impinger collects the dust by aspirating the air and then impinging it onto e flat surface covered by a liquid in a container. The liquid used was distilled water, containing 50 percent alcohol to i 0100 3 prevent the Rolution of some of tlm duals, particularly any adira wliir.Ii niifclit bo present. Tlio iinpingor was actuated by an ota.lrirally driven rolnry pump and Uio rate of air rainpled wns measured by means of a resistanco typo of How meter with an inclined manbnio* ter for measuring. tlm pressure difference. Kneli sample represents Hie dust collected from a volume of 100 cubic feet of air. The electric precipitator is desiipied upon the Cottrell precipitator principle used for recovering dusls nnd fumes nommorcinlly. This principle depends on electrifying the dust particles by making them puss through an electrostatic field and thus causing them to sctllo out upon a sheet of celluloid. Tito electrostatic Held is set up by means of a transformer operating from the lighting lines on 120 volts, alternating current. Air is drawn through Urn apparatus by a small rotary fan, run by a motor, tho quantity being measured by a flow meter. Samples of dust brushed from beams and pipe lines near tho ceiling also wore secured for chemical analysis. All samples were shipped to tlKs industrial hygione laboratory of tho Metropolitan Co., and tho dust counts wore mado according to tho methods accepted by tho United States Bureau of Mines and the United Slates Public Health Service (1). Particles in size up to 360 microns in tho greatest diameter wore counted. Chemical analyses were mado for total (freo and combined) silica according to tho accepted standard method of HHlcbrand (3). In the first plant atudied (A) only particles 10 microns and under in size were counted. It has been demonstrated repeatedly that no silica particles exceeding 10 microns (a micron equals one-millionth part of a meter or one-thousandth part of a millimeter) in greatest diameter enter the lung tissu ; for this reason, tho larger particles usually are not considered when determining dust counts. Lator, as it appeared from soino of the publishod articles (4) (English) that asbestos particles much larger in size were found in lung tissue, it wns decided to count all particles and mako differential counts of all those 10 microns and under.1 Total particles per cubic foot and tho corresponding weight of tho dust in mOEgnuna were obtained. Since no relationship between tho dust counts and tho corresponding weights was found, tho weights are not included in tho tabulations in this report. Table 1 shows by plants and by departments the maximum and minimum dust counts in mUHon particles par cubic foot of air. Although the counts in plant A are of particles 10 microns and under, tmqtm noSnatni kr MS Um (apint* nad ll ilirirn pMlplul* n inwntnd. St iMMa, atonWMnOTptp n( than dm pMtlcfcnwmtalnKndbrbnlaipnfacinddanasterna vttfcnlnawnSMi pStlti ttt nshrtnd pnrtldtn bttag ----d rt> > nrtn. Xonvta* thtattn hnaw (bp am masaOi S *w war.* taW* tat n***l pnrtidt da as. B thsmtfBWn m InmUhadi puNiamr paptr, Ibt Inaatthm tf tat fttseUta t* bn anant gi tfea mm afcnm an 4 and in the other plants are for nil particles, direct comparison is possible, as in no siuhplo taken were tho number of particles 10 microns and under less than 04 percent of tho whole. Tabu 1.--Maximum and minimum Hurt eonnU in million paHide* per enhie foal [ air, bp plant and deportment Put A IWO ThutO naa d HmU S Thymtmm* Ntdft* beraf pta UkM Mtmw w imlrr Nm> brraf ML pw cnM* tend pS lain MdUflfl nartlecf ra tRolh*iC* air NomTweaf Wl*K Ukan MlWra Jttr mbit Mef air XhorrtfMP*irma utra Num- Mint** parti* Wramtir*i rfc t*f pipe culJe l*c Mof ra<4r Ir faotaf moha* frhan<ho*< IT at a* \ CrifninMl mywilwmt.i._._._.._._._.._._.. King (tmm ipianln Twirtmc.......... HYvhtriKrteteMtrtme*mt.b.a.--nd-- i H-IH M-m U- 94 M-4 1 t )Vl jS2k t 2 43 aaS iMm*- 3? -- ii* --- 2 W- K i i M -n -TO i a t >St'*|.-*7 10'iiaH -- >iartotkd ia aptaatac. ladwriw liwii item twrtw. Wlicrcns tho dust m the preparation room is practically all due to asbestos, tho contrary is tho easo in the other departments. In Uio carding, spinning, and woaving rooms asbestos comprises about 25 percent of tbo materinl umxL On special jobs the pcrccntitgo of asbestos may bo higher, but in general the figure quoted is approxi mately correct, tho other material consisting principally of cotton. In the insulating departments of plant A, asbestos is but 5 percent of tho total material used. In tho molded brake-lining and dutch division of plant D, asbestos comprises about 25 percent of the total material Tho actual exposure to asbestos dust, therefore, is Consid erably less than is indicated in the dust counts in table 1. coNomoKs iv tub plants The processes in these plants were very similar to thoso in cotton im'lh in general. For illustration, the process in the preparation room of plant B is here dotoSod at length: Asbestos is received in begs. These are emptied upon the floor and tbs asbestos is shoveled into pug mills and run for about 5 minutes iarprder to crush and open the fibers. From there the asbestos is shoveled into tracks and wheeled to hoppers with either horizontal drsvtical openers, similar to those used in textile mills. After passing through the opener, the material is discharged into trucks. Waste manufacturing material is first ran through'a garnet machine and 0102 I v V\ 5 jumtr * m discharged into trucks, which are wheeled to Llto openers, and Mis material b fed into these in' tta same manner as is the new material. After licing discharged from tlie opener, tta material is put onto a rihrating or shaking screen, where tho long fibers are picked off by a suction hood and blown into a bin to bo used again in textiles. The start fitaro falling through tho screen nre either sold ns such or used in making an asbestos cement Tho cotton b received in bales, opened, and also ran through vertical openers. It b discharged into trucks. The filled trucks from the vertical and 1torirental openers containing cither the ashestos fiber, Die cotton, or tho waste material are taken to separate storage bins. As needed, Uteso materials are weighed and dumped onto tho floor in proportion to tta mixture desired, and Uto resulting mixed materials are then passed through a mixing picker. As this mixture is discharged from the picker, it is sprayed with a light mineral oil. The material is then taken by a mechanical conveyor to tho storage bin in tho card room. Two of there mixing pickets discharge onto thb conveyor system, wliilo a third moehino b equipped with a suction dovice which conveys tho material to a storage bia in the card room. The object of tta two systems b to facilitate the handling of two grades of material at the same time. Tho third maehino b not equipped with an o3 spray. Tta objeet of tho oil spray b pri marily to entrap the small asbestos fibers and hold them enmeshed in the cotton fiber throughout the processes of carding, spinning, and weaving. Incidentally, it b apparent that it also diminishes tlte amount of dust. The material is saturated with about 4 percent of oil at thb point; but by the (into it reaches the looms, the oil had diminished to less than 1 percent. While mineral oil was used in the preparation room of plant C, it apparently was not as efficacious as in plant D. In plant E oil was not used, nor was there any attempt at humidification or anysystem of dust exhausting. Carding machines were fed by hand. In plant A there was a humidifying, ventilating, and heating system, while plant B depended on natural humidity. In plant the carding machines were equipped with a duat-oxhaust system, but it eras not efficiently used. In plant C carding wm dono in 2 buildings, 1 of which was equipped with an air-conditioning system, and m both buildings the machines had exhaust equipment. Two plants, B snd C, had artificial humidity installations in their '< spuming rooms. In the former the temperature was 76 ., relative Effmidity 78 pareent. One plant, C, had a humidification system in this twisting department and also in the weaving department, where tbs relative humidity was 76 percent with a dry-buib temperature of 60 as compared with a relative humidity of 44 percent in tho weaving room of plant A. / 0103 awWMiJi*,, *v-v V;- 'u X^ '\ \ v 't 6 Asido from pliuit E, it would appear that (be dust hoxanl was not excessive except in the preparation rooms of plants B and C. The dust counts arc interesting, too, whon considered in the light of tho pennissihlo standard for granite dust, established by tbo United Slates Public Health Scrvico (7), namely, about 10 million particles (10 microns and under) per cubic foot. Ilowcvor, we are not justified in ossumine tlmt because available information suggests that hmWstosia is a milder disease clinically than silicosis, the threshold of l>ermiHsihln dtwt counts in Incline. Asliestosis appears to be pttt.lmlogically different from silicosis, and the ex|ierienee so far <l<n-i not warrant an attempt to dofino a. slnntlnrcl of dustiness for usbestos dust. DOST CONTTtOT. Various measures, such as oiling, humidification, and local exhausts, tended to reduce the dust. Nevertheless, it was ovident that they were only partly successful. If it is expected to control (lustiness in tlieso plants, final reliance must rest upon properly constructed exhaust equipment. In plant C in ono department an experimental installa tion vras sot np. In spite of somo obvious faults, this equipment, on tho basis of comparative dust counts, reduced the dust by 50 percent and with further alterations will probably be 75 percent effective. In this ease such a reduction seemed quite satisfactory. It is neither practicable nor economically desirable to install such equipment as will make the air entirely dust free. Tho normal defensive mechanism of tho body takes care of a fair amount of atmospheric pollution. It is when tho body is exposed to an exccssivo amount of dust that this dofonso mechanism breaks down. Tho application of exhaust equipment to textile machinery involves considerable difficulty, especially where tho construction of tho ptant is sueh that it is not possiblo to apply down-draft suction to tho looms. It is desirablo to install exhaust apparatus in any plant on nn ex perimental basis first, and then check its efficiency by dust counts. This practice will result in saving a needless expenditure of money. nrrsteax. exakqmaohs X-ray films wore mode of 126 persons (108 men, 18 women) working in sabwtos plants in the United States. All but five of these were given physical examination. The cases were selected more or less at random from among those haring more than 3 years of employ ment in the industry. It was soon obvious that tho early diagnosis of ssbestoeis must rest to a large extent on X-ray pictures of tho chest. As in the early stages of sQieoas, tho clinical symptoms of the asbestos workers wore usually indefinite and inconclusive. Tho interpretations of thaso films are based on tbs readings of ono com petent roentgenologist, but they havs been reviewed by several 0104 t J v \ 7 itHHwrr <* rm olhi-r.: experienced ill tltin field. Till* difTermre* of opinion Wen* of A minor natiim, ami liiriti was general ngrccmonl << to inlrrprt'Ulinu. Tlie films were road conservatively, taking into nrrount (In' physical examination nml the age of tlio individual, nml worn classed ns jmsilivo only whon there was no major disagreement. All rxnminorn wmt guided by their experienee in Riliensis anil other type* of pneu moconioses. Thn films elnwird ns nrgnlivn for nslwsloxis were further subdivided into ilotibtfill nml negative. Only Limn rnu (HI wlu'l.h. r llm individuals classed n doubtful nnt progressing Imvurd n definite asItrstosM. Particular attention wax focussed on I bo presenrn or iilisrnro of indications of tuberculosis, nml in this respect nil thn rovirwrr* of Uio films worn in arronl. WiLh llm unlmppy oxpericnco of rilirusis in mind, it wna felt that a great iletvl of corn should ho devoted to ascertaining, if possible, wlictlirr or not nsbosUmis pre disposes to tuberculous infection. The rnscs of nsbestosis were divided into two classes, first stage and second stage. Tbo first stage embraces those who show by X-my examination definite lung pathology snflicient in extent to warrant a diagnosis of pneumoconiosis, but who have no definito symptoms. Tlio seeond-stago eases exhibit more extensive lung patiiology and also definite symptoms. All these individuals 1 wero actively engaged in factory work, and it was not practicable to mako any distinction on the basis of working ability or disability. Had any individuals been found who exhibited extensive pulmonary involvement and marked physical disability or total disability, they would havo been classified aa third stage, but no such eases were found. Of tbo total of 136 X-ray examinations, 4 wen diagnosed as sceond-dcgrro asbestosis, 63 as first degree, 30 as doubtful, and 20 as negative. There in a definito increase in the percentage diagnosed os positive in relation to the yean of exposure, as shown in tablo 2! Small numbers make it impossible to determine bow far the factor of age enters into this increase. Taaia 3. CTain/rnfig* tfeat** hy yeart tf expttur* i :^v- v i i y i i N ' /` ' K 0105 )nu*r,m 8 Of the (M persona Riven physical examination-and diagnosed m having positive asbestosis, only 8 were entirely free from symptom*, while 10 out of 37 with doubtful 7 out of 20 with nogntivo diglumes worn free from symptom*. Dyspnoea and cough were Urn symptoms moat complained of, but none of these ense* exhibited the urgent or evident type of "short wind" seen in true *Hieiwm. Scvcml of those classed oSnegativo stated that they were "short winded" nnd wero so recorded, hut too much emphasis should not he plurcd on statement* of suhjoetive symptoms. During (Jin progress of the study, physicians who wero practicing in Uio communities where nsliestos workers lived wero questioned anti stated that they did not find an unusual amount of tuberculosis among them workers. Thn contrast botween tins atato of affairs and that found in a community with a silicosis hazard is noteworthy. The incidence of tuberculosis (based upon X-ray films) is given in table 3; 40 of tho 07 examined had less than 15 years of employ* mont in the industry. Tabus 2.--InaAnta / l*bcmtari* 4 rwnw* DmMM KTCmthn Tt it mM 3 X 'TWssmewMstaiHwarMKiMUiXcir Table 4 gives information as to physical signs of chest trouble. Tabus 4. -- CWrt /IntHtigt MtH* DaptoM Ninth* aas at3 Va t7t) 30 > A1StMUMISMiIa isttnati What ngnifieanee, if any, can be attached to the presence of . "asbestos corns" on the hands of workers appears doubtful, as 18 . porosnt dTths poeMves (12 out of 04) and 15 percent of the others (doubtful*7: oat of 37, negative, 2 out of 20) showed such corns. Each roentgenologist who reviewed the X-ray films caUod attention X :'to tbs fset that these films mdieatod a very unusual incidonco of enlargement of the heart. It is probable that this is a compensatory enlargement duo to the additional work put upon the heart in efforts 0106 -12- slight irritant ofiect on the mucous xeabranes, its 'r^sencs nsy be suspected by a=hna of s/aell. Perception of ataeLL appears to dLstinisfa *Lth prolonged "vposure or high c oric.-ntration3. The observations of FsirLcy indlcetr? that concentrations ot the order of 1 in 1^330 to 1 in 5D0 could readily be tolerated by voricers for ' prolonged periods without any warning subjective eyaptons. The fatal effects of exposure to dioxan in industry *ra clearly brought out in England eevn years tgo than five workers La <=n Rrtificisl silk factory dlad. Three stages have or >n described, the first being characterized by irritation of the neso-pharynor end of the ejrea, but if the exposure is continued, the IrritatLon any subside and thus give Tire to a false sens* of security. Symptoms of drowsiness, vertigo, end gastric disturbances may be present, but if a rest of twenty-four hour* is t taken at this stage, these tend to pass off quickly. kith further continued Inhalation, tha second stag* 1? r^schad. The gastric syaptoas become nor severs and are associated with pain and tenderness Ln the abdomen and lumbar region. There nay be enlargsaent of the liver. Tha third stage is characterized by acute haemorrhagic nephritis, leading to suppression Of urine, uraemia, conn, and death. Mention finally night be made of one nor* of the solvents, namely, furfural, which is the only aldehyde of laportance as a pyroxylin solvent. It also has recently bean used successfully as an ingredient in paint, varnish and lacquer reaovors. Khan eondaneed with phenol it gLves resins analogous to baicellte. Its odor is disagreeable to most users and ita vapors are Irritating 'and nay be damaging to tha eyesight. The measures at our disposal for preventing toxic concentrations of solvents escaping into the plant atmosphere fall within three special fields of endeavor, the safety, engineering and medical. Safety measures must be employed against accidsnts and irregularities in operation. Labels on cans and drums X should indicate tha haaardous metare ef the substance and workman should be ,, 2349 Instructed as to dangers. Personal protective devices, such ss protective X -13clothing, gogglea and respirators shouLd be provided when necessary. Good housekeeping and sanitary facilities are esientlsi tad Include eegrt.jii.tijn of processes, care of soLliid solutions, receptacles for soakad rags, eaple general ventilation, and provisions for showers, lockf.ra, lunch rooms, and drinking facilities. A survey to determine the presence of low concentrations under normal operations .nay be indicated. This Leeds us into t. field of detalLed technical work which *e * '.Li not ciscuss h?re. "he results, hor*yer, glvo Inportant infornatlon regaining the necessity of eaploylsg local exhaust ventilation or giving consideration to substitution or entirely enclosing the offending nroeese. Medical supervision to be effective prceueea a knowledge of the physiological action of toa solvents in use and sufficiently frequent physical examinations including special diagnostic methods for the detection of early intoxication or disease. ' V. 23iJ0