Document JN1gVr09NNjN33Mdj4paMY4N6

l\ Il r. S'7 TJjrI .I rarv, PUBLIC HEALTH REPORTS VOL. SO JANUARY 4, 1935 NO. 1 EFFECTS OF THE INHALATION OF ASBESTOS DUST ON THE LUNGS OF ASBESTOS WORKERS A Preliminary Study I'y A. J. Lanza, Assistant Medical Director, William J. McConnell, r.nt Medical Director, and J. William Feu n'el, Chcmi'.t, Metropolitan Life Insurance Co. INTRODUCTION In 1920 the Metropolitan Life Insurance Co. was approached by officials representing the asbestos industry in the United States, who were desirous of ascertaining whether asbestos dust was an occupa tional hazard in their establishments and, if so, what was the nature of this hazard and what should be done to prevent or control it. About this time several 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 typo of pneumo coniosis had been described in American journals, the industry itself appeared to be quite uninformed of the existcnco of any such occupational disease. The hazard of silica dust, with special reference 'p the lungs, has long been appreciated, and a great deal of st- , pd research has been applied to the problem (in the mctnl rr j hnd certain other industries) in Great Britain, the United u.i.vCs, the British Do minions, and in other countries. The nnturo of the. effects of silica dust expressed in the term,, "silicosis", with the resultant extraor dinary predisposition to pulmonary tuberculosis, is well known. ! hose eirrets have been associated with the inhalation of dust con taining frre silica in varying amounts. The effects upon the pul monary tissue of dusts containing combined silica--silicates--are 'till a fertile field for investigation, but evidence is acr.umulating that certain of these dusts produce pathologicnl results quite distinct from true rilirnsis. 1 he name "nsbostosis" has been applied to the pneumoconiosis causeif bv asbestos dust and it will be so used in Ibis report. Chemicullyi the asbestos of commerce is a hydrated magnesium silicato ct'nsisting primarily of silica (combined silica) 44.1 percent, mngne.-ia .(:) percent, and water 12.9 percent, while ferrous iron and mckel me present in sitinll quantities. This commercial variety of tomc-.i;-----1 U) 4,-. asoesics most commonly encountered is designated as ckrysotilo and prevent the solution of so is one of the four varieties of the mineral serpentine, in which it which might bo present. 1 usually occurs in scams. cally driven rotary pump a; It should be borne in mind that silicosis (and presumably nsbes- by means of a resistance tvp, tosis) develops very slowly, tailing from S to IS and even 20 or 20 ter for measuring the presst years to become established. This rato of progresses influenced the dust collected from a vo mainly by the dosage of silica which the lungs receive, and this dos The electric precipitator is age, in turn, depends upon three variables--the amount of silica in principle used for recovering the dust, the quantity of dust in the air, and the length of exposure. principle depends on electrify Individual idiosyncrasy might be included as a fourth variable; pass through an electrostatic however, little is known of the variations in susceptibility in those out upon a sheet of celluloid exposed to dust. It might well be assumed that similar variables means of a transformer operat: would influence the occurrence cf asbestosis. . alternating current. Air is dr. In places where asbestos is mined or fabricated in North America rotary fan, run by a motor, th there does not appear to be present the clcnr-cut clinical picture meter. which is so unescapable in communities with a true silicosis hazard, Samples of dust brushed frotr. such as hard-rock mining communities. It may be that some of the also were secured for chemical a asbestos plants are of too recent origin for the typical effects of a the industrial hygiene laborato; silicate dust to become manifest, but this would not apply to the dust counts were made accordi older mines or to all of the fabricating plants. United States Bureau of Mines : The industrial health service of the Metropolitan Life Insurance Service (i). Particles in size : Co. undertook the following investigation during the period from diameter were counted. October 1929 to January 1931, which included; . Chemical analyses were made 1. A study of dust conditions in asbestos mines and mills in Cannd.a according to the accepted stand: and in fabricating plants along the Atlantic Seaboard in the United In the first plant studied (A) States. in size were counted. It has be 2. Physical examinations of asbestos workers, including X-ray silica particles exceeding 10 mic films. part of a meter or one-thousand 3. A study of dust exhaust systems designed to eliminate asbestus diameter enter the lung tissu ; dust. ' usually are not considered when Data on the fabricating plants ouly nre included in this study and it appeared from some of the p are designated in the report as plants A, B, C, D, and E. This is a asbestos particles much larger in preliminary report. A more extensive study of the asbestos industry decided to count all particles and is now under way. 10 microns and under.1 DUST STUDIES Total particles per cubic foot : Apparatus and methods of sampling.--Both the impinger (1) and the electric precipitator (2) were used for the collection of air samples for dusts at the breatiling levels and in close proximity to the workmen. Both of these forms of apparatus are adapted for this work, as they arc transportable, easily set up and adjusted for the taking of the air samples at the proper level, and are extremely efficient. The impinger collects the dust by aspirating the air and then impinging it onto a flat surface covered by a liquid in a container. The liquid used was distilled water, containing 50 percent alcohol to dust in milligrams were obtained dust counts and the correspond are not included in the tabulatio - Table 1 shows by plants and minimum dust counts in mil)i< Although the counts in plant A a * Samples collertad bf both tha Implnter *r.d nilGopbotocraphs of tbeaa dust particles vers es! ilida projector, the aolastcd pwttdcs boiot iomxj t&uai measuremoat), it tm easy to calculate ifc lofiiiihmtc probability paper, tbt logarliluas of; plottad u ordinates ao-i&st tba probability of oar 2 encountered is designated as chrysotile and lies of the mineral serpentine, in which it mind that silicosis (and presumably ashesly, talons from 5 to 15 and even 20 or 25 shed. This rate of progress is influenced silica wiuch the lungs receive, and thi3 doson three variables--the amount of silica in dust in the air, and the length of exposure, might be included as a fourth variable; of the variations in susceptibility in those 'ht well be assumed that similar variables rence of asbestosis. - " ' os is mined or fabricated'in North America t present the clear-cut clinical picture . jmmunitics witli'a true silicosis hazard, .'communities. It may b<rthat some of the >o recent origin for the'typical effects of a manifest, but this would not apply to tho ie fabricating plants:' - '. service of the Metropolitan Life Insurance wing investigation" during the period from 1931, which included: ' ' lilions in asbestos mines and mills in Canada along the Atlantic Seaboard in tho United ^ ns of asbestos workers, including X-ray U3t systems designed to climinato asbestos . plants only arc included in this study and *t as plants A, B, C, D, and E. This is a rc extensive study of the asbestos industry DUST STUDIES ` if sampling.--Both tho impingcr (1) and wore used for llic:eollection of air samples els and in close proximity to the workmen, untus arc adapted for this work, as they pul adjusted for the taking of tho r."V-<tn<l arc extreinely'efficient, c dust by aspirating the air and then face covered by .v'liquid in a container, water, containing 50 percent alcohol to O Jvxmy 4, Isis prevent the solution of some of the dusts, particularly any silica which might be present. The impinger was actuated by an electri cally driven rotary pump and the rate of air sampled was measured by means of a resistance type of flow meter with an inclined manome ter for measuring. the pressure difference. Each sample represents the dust collected from a volume of 100 cubic feet of air. The electric precipitator is designed upon tho Cottrell precipitator principle used for recovering dusts and fumes commercially. This principle depends on electrifying tho dust particles by making them pass through an electrostatic field and thus causing them to settle out upon a sheet of celluloid. The electrostatic field is set up by means of a transformer operating from the lighting lines on 120 volts, alternating current. Air is drawn tlirough the apparatus by a small rotary fan, run by a motor, the quantity being measured by a flow meter. Samples of dust brushed from beams and pipe lines near the ceiling also were secured for chemical analysis. All samples were shipped to the industrial hygiene laboratory of the Metropolitan Co., and the dust counts were made according to the methods accepted by the United States Bureau of Mines and the United States Public Health Service (1). Particles in sizo up to 300 microns in the greatest diameter were counted. t Chemical analyses were mndo for total (free and combined) silica according to the accepted standard method of Hillcbrand (3). In the first plant studied (A) only particles 10 microns and under in size were counted. It has been demonstrated repeatedly that no rilica particles exceeding 10 microns (a micron equals onc-millionth part of a meter or one-thousandth part of a millimeter) in greatest diameter enter the lung Lissu ; for this reason, the larger pnrticiea usually arc not considered when determining dust counts. Later, ns it appeared from some of tho published articles (4) (English) that asbestos particles much larger in size wore found in lung tissue, it was decided to count all particles and make differential counts of all those 10 microns and under.1 Total particles per cubic foot and tho corresponding weight of tho dust in milligrams were obtained. Since no relationship between tho dust counts and the corresponding weights was found, the weights arc not included in the tabulations in this report. Tabic 1 shows by plants and by departments the maximum and niinimum dust counts in million particles per cubic foot of air. Although the counts in plant A arc of particles 10 microns and under, * -evnpii rnllwrud hy both ths Imptnrer nA ih* Hrrtrfe precipitator eonntart. \n o*Miiloa, ml<*fftf*holnjTRphA of ilusl pnrtJclM *er enlarcod by beta* projected upon risjo nth a lAniero- prrj^tor, the toift/erd pA/tlrle) bclflf Uh * ruler. aoowIdc the entire enlwcrmeni (by (3).me-vcurcmeni). jj ry exiy tn cnlculnta Ihi nricioal pvtlcle size Tlj* lh* uu *; |l *<*** * ,M (trnhfchilitr pAper, the of thn funr,,nn ia *4 Aflinrttfl AflMl.t f '* * . ................... and in the other plants aro for all particles, direct comparison is possible, os in no sample taken were the number of particles 10 microns and under less than 94 .percent of tho whole. Table 1.--jl/an'mum and minimum counfs in million particles per cubic foot of air, by plant and department Phot A ?lm D runt c Plain D Plant S Department Million Num ber of ** tu ples taxes pnrti* cries under 10** per cubic loot of *ir Rinc fr.ua* sptoomc Molded brU:* band $ 14-1 It 2 h-l*4 * * >t- *; 10 t<r*W 6 3 >4-< i Included (a spiaoioc. ?.& 3 --3 Million pani cles per CUbK loot or air Num ber of sam ples taken M niton port!cies per cubic root or air Num ber of .'re ntes Uktn Num Million ber of parti sam cles per ples cubic }<r foot o ruhic ur foot of tr Million parti cles per cubic foot Of *r 9 & U-8 s 2 -n 6 ......... . 30 -R2 3 'JQ -?ii 5 () h- a 2 til- 4`* fl2 M 2h 3M-10 ........; i -.in IS 1-7 joI-hom 14* * * Includes breed loom vearlnc. TThereas the dust in the preparation room is practically all due to asbestos, the contrary is the case in the other departments. In the carding, spinning, and wearing rooms asbestos comprises about 25 percent of the material used. On special jobs the percentage of asbestos may be higher, but in general the figure quoted is approxi mately correct, the other material consisting principally of cotton. In the insulating departments of plant A, asbestos is but 5 percent of the total material used. In the molded brake-lining and clutch division of plant D, asbestos comprises about 2-5 percent of the total material. The actual exposure to asbestos dust, therefore, is consiu'erably less than is indicated in the dust counts in table 1. CONDITIONS IN THE PLANTS The processes in these plants were very similar to those in cotton mills in general. For illustration, the process in the preparation room of plant B is here detailed at length: Asbestos is received in bags. These are emptied upon the floor and the asbestos is shoveled into pug mills and run for about 5 minutes in order to crush and open the fibers. From there the asbestos is shoveled into trucks and wheeled to hoppers with either horizontal or vertical openers, similar to those used in textile mills. After passing through the opener, the material is discharged into trucks. Waste manufacturing material is first run through a garnet machine and discharged into trucks, which i material is fed into these in the After being discharged from tlu vibrating or shaking screen, wLu a suction hood and blown into The short fibers falling through t used in making an asbestos ccmei Tho cotton is received in bal vortical openers. It is discharged the vertical and horizontal open, fiber, the cotton, or the waste mat bins. As needed, these materials . Goor in proportion to the mixture materials are then passed through is discharged from the picker, it is The material is then taker, by a nv bin in the card room. Two of tin this conveyor system, while a th. suction device which conveys the card room. The object of the two s; of t'.vo grades of material at the s. not equipped with an oil spray. 1 ninrily to entrap the small nsbestoin the cotton fiber throughout the p weaving. Incidentally, it is appa amount of dust. The materia! is s oil nt this point; but by the time . diminished to less than 1 percent. While mineral oil wns used iu tlu apparently was not as efficacious a.not used, nor was there onv nttemp of dust exhausting. Carding machir there was a humidifying, ventilat plant B depended on natural him machines were equipped with a du; efficiently used. In plant C cardii which was equipped with an air-ct buildings the machines had exhaust Two plants, B and C, had artifici spinning rooms. Iu the former the humidity 78 percent. One plant, C the twisting department and also in the relative humidity wns 76 perccn GO0 F., as compared with a relativ. weaving room of plant A. 4 ro for all particles, direct comparison is taken were the number of particles 10 m 94 percent of the whole. /sun dust counts in million particles per cubic foot by pianl and departjnenl Ptant B Plant C PUot D Phot E 'um* i-r of Un pies .jken Minina partidel pet cuhie foot of tir Xum* ber of Tri ples taken Million Poli cies t*er cubic foot of if Num Num ber of sam ples taken Million ber of parti- sam do per ples cubic [ter loot of cubic alf foot of if Million parti cles per cubic foot of ir 9 4 h- ti S 2 -n s Jti-idli 3 ill- 4is 3 i 6 3*t-l0 . n l -7 3 30 2 a -;s 3 37 3 2 1 Includes broad loom wearing. preparation room is practically all due to lie case in the other departments. In the aring rooms asbestos comprises about 25 ;sed. On special jobs the percentage of it in general the figure quoted is approximnterial consisting principally of cotton, nts of plant A, asbestos is but 5 percent In the molded brake-lining and clutch >s comprises about 25 percent of the total -lire to asbestos dust, therefore, is considl in the dust counts in table 1. ION'S in tut. r t.A NTS ants were very similar to those in cotton ltimi, die process in the preparation room t length: :s. These arc emptied upon the floor and i pug mills mid run for about 5 minutes jvers. From there the nshestos is a.- to hoppers with either horizontal those used in textile mills. After passing ierial is discharged into trucks. Wnsto rst run Lhrough a garnet machine and 5 liaoT7 1, iS3j discharged into trucks, which arc wheeled to the openers, and the material is fed into these in the same manner as is the new material. After being discharged from the opener, the material is put onto a vibrating or shaking screen, where the long fibers arc picked off by a suction hood and blown into a bin to be used again in textiles. The short fibers lolling through the screen are either sold as such or used in making an asbestos cement. The cotton is received in bales, opened, and also run through vertical openers. It is discharged into trucks. The filled trucks from the vertical and horizontal openers containing either the asbestos fiber, the cotton, or the waste material arc taken to separate storage hins. As needed, these materials arc weighed and dumped onto the floor in proportion to the mixture desired, and the resulting mixed materials arc 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 the storage bin in the card room. Two of these mixing pickers discharge onto this conveyor system, while a third machine is equipped with a suction device which conveys the material to a storage bin in the card room. The object of the two systems is to facilitate the handling of two grades of material at the same time. The third machine is not equipped with an oil spray. The object of the oil spray is 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 is apparent that it nlso diminishes the amount of dust. The material is saturated with about 4 percent of oil at this point; but by the time it reaches the looms, the oil had diminished to less than L percent. While mineral oil was used in the preparation room of plant C, it apparently was not as rifirncious ns in plant II. In plant E oil was not used, nor was there any attempt at humidification or any system of dust exhausting. Carding machines were fed by hand. In plant A 1 here was a humidifying, ventilating, and heating system, while plant II depended on natural humidity. In plant K the carding machines were equipped with a dust-exhaust system, but it was not elliriemly used. In plant C carding was done in 2 buildings, 1 of which was equipped with an nir-eondiliuning system, and in both buildings the machines had exhaust equipment. Two plants, 11 and C, had artificial humidity installations in their spinning rooms. In the former the temperature was 70 F., relative humiditv "S percent. One pln,nt, C, h;ul a humidification system in the twisting department and nlso in the weaving department, where the rein live humidity wns 70 percent with a dry-bulb temperature of Op5 I'\, as compared with a relntivc humidity of 44 percent in tho "caving room of plant A. i h 1IN 3 lu T. S.t . > , V* fl u Aside from plant E, it would appear that the dust hazard was not excessive except in the preparation rooms of plants B and C. Tho dust counts are interesting, too, when considered in the light of tho permissible standard for granite dust, established by the United States Public Health Service (7), namely, about 10 million particles (10 microns and under) per cubic foot. However, wo are not justified in assuming that because available information suggests that asbestosis is a milder disease clinically than silicosis, tho tlireshold of permissible dust counts is higher. Asbcstosis appears to be patho logically different from silicosis, and the experience so far docs not warrant an attempt to define a standard of dustiness for asbestos dust. DUST CONTROL Various measures, such as oiling, humidification, and local exhausts, tended to reduce the dust. Nevertheless, it wns evident that they were only partly successful. If it is expected to control dustiness in these plants, final reliance must rest upon properly constructed exhaust equipment. In plant C in one department an experimental installa tion wns set up. In spite of some obvious faults, this equipment, on the basis of comparative dust counts, reduced the dust by 50 percent and with further alterations will probably be 75 percent- effective.. In this case such a reduction seemed quite satisfactory. It is neither practicable nor economically desirable to install such equipment ns will make the air entirely dust free. The normal defensive mechanismof the body takes care of a fair amount of atmospheric pollution. It is when the body is exposed to an excessive amount of dust that tliis defense mechanism breaks down. The application of exhaust equipment to textile machinery involves considerable difficulty, especially where the construction of the plant is such that it is not possible to apply down-draft suction to the looms. It is desirable to install exhaust apparatus in any plant on an ex perimental basis first, and then check its efficiency bj' dust counts. Tills practice will result in saving a needless expenditure of money. PHYSICAL EXAMINATIONS X-ray films were made of 12G persons (108 men, 18 women) working in asbestos 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 the early diagnosis of asbestosis must rest to a large extent on X-ray pictures of the chest. As in the early stages of silicosis, the clinical symptoms of the asbestos workers were usually indefinite and inconclusive. The. interpretations of these films are based on the readings of one com petent roentgenologist, but they have been reviewed by several others experienced in this fide a minor nature, and there was c The films-were read eonservau examination' and the age of positive only when there was in were guided by their expcricnc. moconioscs. The films classed a subdivided into doubtful an whether the individuals classed definite asbestosis. Particular or absence of indications of icb reviewers of the films were in ac< of silicosis in mind, it was felt . devoted to ascertaining, if posji disposes to tuberculous iufection. The cases of asbestosis were < and second stage. Tbe first s: X-ray examination definite lunt warrant a diagnosis of pncumui symptoms. The second-stage pathology and isiso definite"symp All these individuals : were ac: it was not practicable to make an ability or disability. Had any in extensive pulmonary involvemc: or total disability, they would i but no such cases were found. Of the total of 12G X-ray c: second-degree asbestosis, 03 as fir negative. There is a definite increase in ; in relation to the years of expr numbers make it impossible to J enters into this increase. TAnuz 2.--Classifica:!. Vears of exposure Over u years......... 10 to years........ & (o 10 yenr*.,.......... Coder i years........... TotaJ evnmtned ' lMrt time. * Ooa ttbestna worker (second susel retired of hu to tols study, but Is suM active about his jirdeu. t 6 vould appear that the dust hazard was not eparation rooms of plants B and C. The g, too, when considered in the light of the granite dust, established by the United ice (7), namely, about 10 million particles r cubic foot. However, we are not justified available information suggests that asbesc.linically than silicosis, the threshold of lusher. Asbcstosis appears to be pathoiicosis, and the experience so far does not efinc a standard of dustiness for asbestos DUST CONTROL is oiling, humidification, nnd local exhausts, - fevorthcless, it was evident that they _ if it is expected to control dustiness in mist rest upon properly constructed exhaust n one department an experimental instnlla<>f some obvious faults, this equipment, on lust counts, reduced the dust by 50 percent ons will probably be 75 percent effective, on seemed quite satisfactory. It is neither Uv desirable to install suc.li equipment as ust free. The normal defensive mechanism fair amount of atmospheric pollution. It .1 to an excessive amount of dust that tliis down. t equipment to textile machinery involves daily where the construction of the plant to apply down-draft suction to the looms, xhaust apparatus in any plant on an cxthen check its efficiency by dust counts, saviug a needless expenditure of money. ;al examinations 2fl persons (108 men, IS women) working nited States. All but five, of these were The cases were selected more or less e having more than 3 years of employif.yim obvious that the early diagnosis . ; extent on X-ray pictures of the. s of MlicoMS, the clinical symptoms of ually indefinite and inconclusive. The arc based on the readings of one comthev have been reviewed by several 7 Joauary <, iou others experienced in this field. The differences of opinion were of n minor nature, and there was general agreement as to interpretation. The films were read conservatively, taking into account the physical examination and the age of the individual, and were classed as positive only when there was no major disagreement. . All examiners were guided by their experience in silicosis nnd other types of pneu moconioses. The films classed as negative for asbcstosis were further subdivided into doubtful and negative. Only time can tell whether the individuals classed as doubtful arc progressing toward a definite nsbestosis. Particular attention wns focussed on the presence or absence of indications of tuberculosis, and in this respect all the reviewers of the films were in accord. With the unhappy experience of silicosis in mind, it was felt that a great deal of care should ba devoted to ascertaining, if possible, whether or uot asbcstosis pre disposes to tuberculous infection. The rases of asbcstosis were divided into two classes, first stage and .-('ond stage. The. first stage embraces those who show by X-rav examination definite lung pathology sufficient in exteut (o warrant a diagnosis of pneumoconiosis, but who have no definite symptoms. The second-stage eases exhibit more extensive lung pathology and also definite symptoms. All these individuals 5 were actively engaged in factory work, nnd it wns not practicable to make 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 have been classified as third stage, but no such rases were found. Of the total of 12(i X-ray examinations, 4 were diagnosed as second-degree asbcstosis, (3 nr, first degree, 30 ns doubtful, and 20 as negative. There is a definite increase in the percentage diagnosed ns positive in relation to the years of exposure, as shown in table 2. Small numbers make it impossible to determine how far the factor of ago enters into this increase. T.uti.r. 2.--Chixsificntiim nj r/i.v.t hj year, nf rTjiosure Yf.ifl nl CMHttllfC lYfivm.fCc (M'MllVH r.iMtUo N'timltr ' 1 houinfitl ] N'rcuMv* User l.*i 1*1 tM r* ......................................................................... ................ ..........,...................................... *7 Id ' t M3 ; 3(1 U 3 1 T.ui lime. 1 Mu* n'Hfief irs*nn*l u i?i*i rri.rr'l f In* iw n to tins stmt). tin; if >liM .ititt c uUmi( Ins yu/ilcn. l * i not continuum. Urmto o( n|>t tvc. "l jejr* " . '"s ;\.' I i i Of the 64 persons given physical examination and diagnosed as having positive asbestosis, only 8 were entirely free from symptoms, while 10 out of 37 with doubtful and 7 out of 20 with negative dingnoses were free from symptoms. Dyspnoea and cough were the symptoms most complained of, but none of these cases exhibited the urgent or evident type of "short wind" seen in true silicosis. Several of those classed as negative stated that they were "short winded" and were so recorded, but too much emphasis should not be placed on statements of subjective symptoms. During the progress of the study, physicians who wero practicing in the communities where asbestos workers lived were questioned and stated that they did not find an unusual amount of tuberculosis among these workers. The contrast between this state of affairs nnd that found in a community with a silicosis hazard is noteworthy. The incidence of tuberculosis (based upon X-rny films) is given in table 3; 40 of the 67 examined had less than 15 years of employ ment in the industry. Table 3.--/nctWence of tuberculosis Positive Doubtful Negative Tub*rrulo?i3 (heeled)................... ...| Th>rruloi3 (active)............ .......................... ...................... .......................{ Total *u,V2ir.r\!........ ........... ..... ........... ..................................................... 7 >t 67 0 T a * This com w rflacnosiii as probably active on M>c Xray Amlin?*. Table 4 gives information ns to physical signs of chest trouble. Table 4.--Chest findings Positive Doubtful N* restive rhysfcal sipns of chest trouble No physical cas.................... . Not examined............... ........ Total................ ................. A t least fi of thC52 <howe l no nvulrnr? .issonnietJ with nshcstoMS. * 2 of there not M50c:ntel with uunl ju'ens f*um( artxMosis. C of these oot associated with uual sitros of asoesiosis. 33 31 3 67 *0 23 2 39 *7 in u 31 Wlmt significance, if any, can be attached to the presence, of "asbestos corns" on the hands of workers appears doubtful, as IS percent of the positives (12 out of G4) and 15 percent of the others (doubtful, 7 out of 37, negative, 2 out of 20) showed such corns. Each roentgenologist who' reviewed the X-ray films called attention to the fact that these films indicated a very unusual incidence of enlargement of the lnyirt. It is probable that tliis is a compensatory enlargement due to the additional work put upon the heart in efforts i to pump blood.through the fibr. sufficient attention has been paid upon tho heart. Many workers had changed from one plant to another duriiv. asbestos industry. Since only. ill timo of this survey in the var.ou no way of knowing tlie average inhaled by these people over the qucntly, it is not possible to corr amounts of dust exposure. ixsuru.v To throw light on the relation? nary tuberculosis, an analysis of manent disability claims was mm group insurance nnd having avail: Thcro were 2,009 lives involved years. The death claims are so elusions cannot be reached from a same is true of'the sickness cia number of claims for respiratory i studied but low for the others, a experience of 1927. However, ch: first, part of 1929 there was an epi. Tho records of one establishnu denth claims nnd S of 10 permam li.itcd ns due to pulmonary ttibcrv ordinate amount of tuberculosis f: the employees.were Negroes, end ally high in tliis section of the c diagnosing pneumoconiosis and tuberculosis, these, claims wore s;who had treated the individuals nnd sanatorium records, includ investigated, with the following n Death, claims: _ 1. A typist, not exposed intestinnl tuberculosis. . 2. Colored male, age 27: months; died of pulmonary r wns in sanatorium 10 mont! mann. No evidence of nsbc ' 3. Colored male, age 32; m 7 months; died of pulmon.hospital. Cavitation both lu 8 ven physical examination and diagnosed as is, only 8 were entirely free from symptoms, doubtful and 7 out of 20 with negative diag- ymptoms. Dyspnoea and cough were the ned of, but none of these cases exliibited the I' "short wind" seen in true silicosis. Several tire stated that they were "short winded" at too much emphasis should not be placed ive symptoms. During the progress of the were practicing in the communities where ere questioned and stated that they did not of tuberculosis among these workers. The itc of affairs and that found in a community noteworthy. 1 -y'osis (based upon X-ray films) is given in ned hud less than 15.years of employ- : 3.-- Incidence t>f lubtrculutis Positive Doubtful S'cRAtlve 1 47 t 0 39 2 \ 20 ,y nctive on the X^r.iy fliuiioci. ion as to physical signs of chest trouble. \IU-E -- Chat findingi To'ltu-e Doubtful X'rgatlva *33 *9 31 3 i 7 *7 13 0 a> i%tth n> Imwiil vtiJi ns of * * - * :* y, can be attached to the presence iff amis of workers appears doubtful, as IS out of lit) ami 15 percent of the others live, 2 uut of 20) showed such corns. wed the X-ray films culled attention : pleated a very unusual incidence of t is probable, that this is a compensatory :ional work put upon Iho heart in efforts 9 Jisasr? 4.1ZU to pump blood through the fibrosed lungs. It is possible that- not sufficient attontion has been paid to the effects of the pneumoconv-vcs upon the heart. Many workers had changed from one department to another and from one plant to another during their years of employment ir- Jie asbestos industry. Since only the amounts of dust collected ns il.e time of this survey in the various departments aro known, thfcn* Is no way of knowing the -average amount of dust in the atme-^-dme inhaled by these people over the years of their employment. -O.'Crsoipicnlly, it is not possible to correlate individual cases with c-n^fsb* amounts of dust exposure. INSUn.vXCE CLAIMS 'To throw light on the relationship between asbestosis and piibte uary tuberculosis, an analysis of death claims and total and 7ermaiient. disability claims was made in regard to companies c;'rc';.:.-rg group insurance and having available figures. There were 2,099 lives involved, with a total exposure of 7.fi:.':K years. The death claims are so small in number that reliable utl'hisions cannot be reached from any subdivision of the figures. Tb.-e same is true of iho sickness claims under health insurance. Th.-a number of claims for respiratory diseases is high in two of .the iTiuvms 'I tidied but low for the. others, ns compared with the Mefcooiuirerci experience, of 1927. However, during the latter part of 1927 amd siV-ii first pact of 1929 there was an epidemic of influenza. The. records of one establishment (plant D) showed thr-i. >9 mf TS death claims and S of 10 permnnent anil total disability c.lc.ma w.wre 'i.-led as due to pulmonary tuberculosis. This appeared te he a-.ti .lo"rdinaic amount of tuberculosis from this plant. Howevei. :nuwy off the employees were Negroes, nnd also tuberculosis claims i.-: gmtutrniiv -high in this section of the country. Kealizing the dff:>!'-,:i.ry ja diagnosing pneumoconiosis nnd the tendency to confus; is- vitii tuherruln.-is, these claims were, studied individually'. The yiiyi::i:ms aim bad treated the individuals were interviewed, nnd t!>-- umi'-utal mul sanatorium records, including available. X-ray lu:;t`\ w'-r-o iuM-.stiguicd, with the following results: Ihnlh {hums:' 1. A typist, not exposed to dust; died of pnlm ani intestinal tuberculosis. ` 2. ('ulored male, age 27; worked in asbestos 1 y-'.v t::vt S nioiitlis; died of pulmonary tuberculosis following a lu.uotn'.-.-.tg-:: a as in sanatorium 10 months. Also bad a four phr- "f.ir m.-itm. No evidenre of asbestosis. 'I. Colored male, age T2; worked in asbestos plant l sr --.v.'-l 7 iiniiiilts; died of pulmonary tuberculosis after 1 c.-t.'.t -a ho'pital. Cavitation both lungs; no evid'-m-.. ; ' \. III ll t J. I! ( !{ ! I! '! < H- 4. Colored male, age 34; worked in asbestos plant 2 years and G months. His physician believes this was a case of uncom plicated tuberculosis. Was not inmate of hospital or sanatorium. No information could be obtained on tho other two cases. Total and permanent disability claims: 1. Male, employed in asbestos plant 3 years. His physicistu states that he first came under his observation with nn old estab lished case of tuhcrculosis about 2 years after asbestos employ ment started. Also had tuberculosis of the kidney and cervical glands. 2. Male, employed in nsbestos plant S months. Ills physician states finding of old fibroid tuberculosis with tubercle, bacilli in sputum. No X-ray available; but according to physician, as bestos bodies were found in sputum. ' 3. Male, 10 years' employment. Two physicians who treated him at different times are now inclined to believe this man is not tuberculous, but has asbestosis. 4. .White male, was reexamined at time of investigation. His ` physician reports well nourished, husky looking, good color, no cyanosis;_no clubbing of fingers; diminished expansion; incessant cough; X-ray shows fine mottling disseminated through both lungs. No evidence of tuberculosis. Probably a second stage asbestosis. 5. White male, 13 years in nsbestos plant. Is now in sanato rium. An interesting case. His physician states that he 1ms ex* tensive asbestosis and pulmonary tuberculosis; cavity in right lung; sputum loaded with tubercle bacilli and nsbestos bodies; believes tuberculosis long antedated asbestosis. This patient is progressing in a satisfactory manner. - It was not possible to locato tho other three cases of total and permanent disability who had been diagnosed ns having pulmonary tuberculosis. On the basis of the information obtained, the deaths in death-claims eases appear to be due to uncomplicated tuberculosis: three of them were Negroes, who were probably tuberculous at the time their employment in tiie nsbestos plant commenced. Of the 8 disability claim cases, 1 was uncomplicated tuberculosis and 2 were uncomplicated asbestosis who were put on disability because of a mistaken diagnosis of tuberculosis. In this same com munity wc know of one death due to uncomplicated asbestosis in nn individual with many years' employment in the industry.3 . CONCLUSIONS 1. Prolonged exposure to asbestos dust caused a pulmonary fibrosis of a type different from silicosis and demonstrable on X-ray films. Clinically, from tlus study, it appears to be of a type milder than silicosis. 2. Coses of definite cardiac enlargement wore frequently found to be associated with asbestosis. * Ftooool communication. * 3. A predisposition to tubi indientod in this study. 4. Asbestosis as observed in marked disability in any case. 5. It is not known bow muc of pneumonia and ncuto nonxu G. It is not practicable as yet dust content of air. 7. The amount of dust In the be substantially reduced. hscom:. It is recommended-- 1. That the industry seriously asbestos plants. 2. That new employees be ex examination of the chest, and re tuberculosis or pneumoconiosis. 3. That employees be examine but at least every 2 years, tkh examination of the chest. 4. That the industry sponsor s ns well as studies on effects of ash acknow: The authors wish to express tl aided in making this study possf plovecs of the asbestos companies and gave every facility for securir. University of Pennsylvania,- for i interpreting X-ray films, and to L States Public Health Service, sun. Bureau of Mines Cooperative C> pretation of all the X-rny films li.prcciatioD is also expressed to Dr. Lynch, of Charleston, S. C-, for i: as to the pathology of asbestosis; ` S. C.; to Dr. Joseph H. Wyatt, I'ellows, of New York, for nssisti' Dr. Paul 0. Snoke, of Lancaster, Danville, Quebec, Cnnnda; and to E. Cummings, of the Saranac Lah study of the pathological effects > * Ait*estasu bodies In sputum sod lunr. By Keen Jour Aa. M*d. Assoc., Auj. JO. 1930, vol.to. do. 9, . 10 ISC 34; worked in asbestos plant 2 years and ysician believes ibis was a ease of uncom- "Was not inmate of hospital or sanatorium, id be obtained on the other two eases. inability claims: (1 in asbestos plant 3 years. His physician -ime under his observation with an old estnbulosis about 2 years after asbestos employhad tuberculosis of the kidney and cervical I in asbestos plant 3 months. Ills physician fibroid tuberculosis with tubercle, bacilli in available; but according to physician, nsuind in sputum. employment. Two physicians who treated = arc now inclined to believe tliis man is not asbestosis. xamined at time of investigation. His unshed, husky looking, good color, no fingers; diminished expansion; incessant fine mottling disseminated through both of tuberculosis. Probably a second stage ears in asbestos plant.. Is now in snnato- case. His physician states that he has ex- pulmonary tuberculosis; cavity in right vith tubercle bacilli and asbestos bodies; ng antedated asbestosis. This patient is ctory manner. . >cate the other three eases of total ami ad been diagnosed as having pulmonary f the information obtained, the deaths in ) he due to uncomplicated tuberculosis; . who were probnbiy tuberculous at the > asbestos plant commenced. uses, I was uncomplicated tuberculosis asbestosis who were, put on disability isk of tubcrmlusis. In this same, omii ilue to uncomplicated asbestosis in an inploymenl in the industry.3 o.vrurstovs icstns dust caused a pulmonary fibrosis ;is mill demonstrable, on X-ray fi'ms. 'Cur-; to be of a type milder than nlargeiiHMU were fictpiciilly found to 11 J0r7 < Id? . 3. A predisposition to tuberculosis due to asbestos dust was not indicated in tliis study. 4. Asbestosis os observed in this series of coses had not resulted in marked disability in any case. 5. It is not known how much asbestosis may add to the mortality of pneumonia and acute non tuberculous pulmonary infections. (i. It is not practicable os'yet to establish standards for t he asbestos dust content of air. _ 7. The amount of dust in the air in the asbestos plants studied can be substantially reduced. recommendations It is recommended-- 1. 'Thafthe industry seriously face the problem of dust control in asbestos plants. 2. That new employees bo examined physically, including X-ray examination of the chest, nnd rejected for employment if they show liibcrndosis or pneumoconiosis. 3. That employees be examined physically, prefcrahly every year, but at least every 2 years, tliis examination to include an X-rny examination of the chest. 4. That the industry sponsor studies on known cases of asbestosis, as well ns studies on cllects of asbestosis on the heart and circulation. acknowledgments The authors wish to express their sinecro thanks to all those who aided in making this study possible., especially the officials and em ployees of the asbestos companies who cooperated to the fullest extent and gave every facility for securing data; also to Dr. Panconst, of tho Uuiverrilv of Pennsylvania, for his interest nnd valuable advice in interpre.tiog X-ray films, nnd to Dr. 1'. V, Meriwether, of the United States Public. Health Service, surgeon in charge of the United States I'uirnu of Mines Cooperative Clinic in Piclier, Okla., whose inter pretation of all the X-ray films listed in tliis report is followed. Ap preciation is also expressed to Dr. W. Atmar Smith, and Dr. Kenneth lynch, of Ubarleston, S. 0., for information and advice, particularly as in flip patltologv.of asbestosis; * to Dr. \\. \Y. \\ ild, of Charleston, s- to Dr. ,To<.-cph II. Wyntt, of Newark, N. J., nnd Dr. H. 11. !->4l,uv!t of Xow York, for assistin;: in interpreting X-ray films; to lb'. Paul (). Suoke, of Lancaster, Pa.; to Dr. R. 11. Stevenson, of Dan villa, (jiudier, Canada; nnd to Dr. L. U. Gardner and Mr. Donald L Cummings, of (tie Saranac. Laboratory, who have undertaken the -ludy ,,f ||,,. pathological effects of the inhalation of asbestos rlu^t * i.. i. I,.-a... ,n Innr. Hr Kcnnfih .\t. 1.} iwl.. M. D . :.c-l W. Atiscv >r. !lt. M. J) \m Mfl.A-ne.Aut M. I'l. \nt 01. no 0. |.|i AW oil. l2 through anur.nl experimentation, with Uio aid of a grant from tho Metropolitan Life Insurances Co. HEFETIENCES (1) Greenburg, Leonard, and Bloomfield, J. J.: The iinpinecr dust sampling ap paratus as used, by the United Stales Public Health Service. Pub. Health Rep., vol. 47, no. 12, Mar. IS, 1032. Reprint no. I52S. (2) Drinker, Philip, ami Thomson, Robert M.: Determination of suspensoids by alternating-current precipitators. Jour. Ind. Ilyg., vol. VII, no. G, June 1925. (3) Rillebrand, W. F.: The analysis of silicate and carbonate rocks. Hull. -122, United States Geological Survey, Washington, D. C. (4) Cooke, W. E.: Pulmonary asbestosis. Brit. Med. Jour., Dee. 3, 1027. (5) Green, H-: A photomicrographic method for the determination of particle size of paint aud rubber pigments. -Jour. Franklin Institute, 1021, pp. 102, 637. ' (6) Whipple, C. C.: Vital statistics. John Wiley and Sons, New York, 1025, p. 451. (7) Russel, A. E., Britten, R. II., Thompson, L. R., and Bloomfield, J. J.: The health of workers in dusty trades. II. Exposure to siliceous dust (granite industry). Pub. Health Bull. No. 137. 1029. ENDEMIC TYPHUS IN ALABAMA 1 By J. N. Baker, M. D., Jaaies G. McAli-ine, Ph. D., and D. G. Gill, M. D., D. P. H., Alabama Stale Department of Health, Montgomery, Ala. I. INTRODUCTION In ft preliminary report made in June of this year before the Con ference of State and Provincial Health Authorities, held in Wash ington, the authors discussed the epidemiological aspects of endemic typhus as it occurs in southern United Stales. In thnt report it was noted that there had been n rapid increase in tliis disease- in certain Southern States, as is shown in table l. That other countries have experienced a similar rise in incidence is evidenced by the figures in table 2. ' " The distinction between epidemic typhus and the endemic typhus of tliis country was first recognized in 1898 by Brill. He (1) found in the United States a type of fever which, resembling typhoid, gave a negative Widal reuclion. In further studies he (2, 3) demonstrated its similarity to typhus, hut showed thnt it wns milder in character and less contagious, only one ease as a rule being found in a household. Also he reported that it was most prevalent during the fall of the year instead of lat-e winter or spring. In 1912 Anderson and Goldbcrger (4) proved that- Brill's disease was immunologically identical with Mexican typhus, or tabardillo. Naturally this led to the belief that it was louse borne. - iRd before tb laboratory ic:ioa of tbo Amerlaa Public Health Auociatioo, Tandena. Calif., Sept* 3. 1934. Taole 1.--Typhtix fever incidence i 6UU florid*..........-...........-................. ............j t Alabnin*............. ..................................................j ` .................-.......... -........................... , Tuu...................*...........--........................................ . , i 4 aaoaihi oaiy. to July L Taole 2.--<'nctj/ence of Country tF'.oi7o?nt.o..f..S...o..u..t.h....A..l.r..t.c.w... Mturo 1............ VmteH States......... PoUod............ Rumania-....... i Prom tba Epidemiolorieal Report. Health Sectioa t neMfu. for C months. Nevertheless, Mnxey (5) (1920) study of Brill's disease, or endemi' its noncontagious character and it; thnt the louse was the vector. Sin< of cases appeared among persons ha to believe that rats and mice migl. disease was carried to man hv Picas, emphasized the fact that Brill's di lower strata of society and bears m step was taken when Dyer, Itumrcable to recover the virus of Brill's been found in typhus foci. Rumreich (7) (1933) has pointed in spite of Maxey's fundamental w the probable vector of endemic, t and arachnids were suspected by vectors were the tropical rat mite, < tho body louse, the head louse, the and the tick. It is now obvious th tho fact that two distinct clinical i for this reason Maxey's observation.The work of Rumreich, D3-cr, and B that thcro arc in eastern and sou; wliich are related both ctiologicaUy is endemic typhus, wliich is transit: other is Rocky Mountain spotted fc