Document LodzXLR1Q2ZBZMk3bZXN57wDb

FILE N A M E: M etropolitan Life (M L) DATE: 1935 Jan 4 DOC#: ML042 D O CU M EN T DESCRIPTION: Public Health Report - Effects of the Inhalation of Asbestos Dust on the Lungs of Asbestos W orkers with Reference to Met Life Pi 's i i /! ' wii -lA`fi'ft,"]'- 'iI T-'.L iaSr1v/ri ; / V^L / PUBLIC HEALTH REPORTS JANUARY 4, 1935 NO, 1 EFFECTS OF THE INHALATION OF ASBESTOS DUST ON THE LUNGS OF ASBESTOS WORKERS A Preliminary Study B y A. J. L a n za , Assistant Medical Director, W il l ia m J. M cC o n n e l l , Assist ant Medical Director, a n d J. W il l ia m F e h n e l , ChemiA, Metropolitan Life Insurance Co. IN T R O D U C T IO N In 1929 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 duo to asbestos dust. While in one or two isolated instances the occurrence of this type of pneumo coniosis had been described in American journals, the industry itself appeared to be quite uninformed of the existence of any such occupational disease. The hazard of silica dust, with special reference fp the lungs, has long been appreciated, and a great deal of st" fid research has ' been applied to the problem (in the metal nr j and certain other industries) in Great Britain, the United oluoCs, the British Do- , minions, and in other countries. The nature of the effects of silica j dust expressed in the term " silicosis", with the resultant extraor- j dinary predisposition to pulmonary tuberculosis, is well known. I These effects have been associated with the inhalation of dust con- - tabling free silica in varying amounts. The effects upon the pul- > monary tissue of dusts containing combined silica--silicates--are \ still a fertile field for investigation, but evidence is accumulating that | certain of these dusts produce pathological results quite distinct from f true silicosis. i The name " asbestosis" has been applied to the pneumoconiosis | caused by asbestos dust and it will be so used in this report. Chem- I ieally, the asbestos of commerce is a hydrated magnesium silicate 4 consisting primarily of silica (combined silica) 44.1 percent, mag- * nesia 43 percent, and water 12.9 percent, while ferrous iron and ^ nickel are present in small quantities. This commercial variety of j 101D3I_35-- 1 (1) - tsl l. i' i I asbestos most commonly encountered is designated as cbrysotile and 3B one of the four varieties of the mineral serpentine, in which it usually occurs in seams. It should be borne in mind that silicosis (and presumably asbestosis) develops very slowly, talcing from 5 to 15 and even 20 or 25 years to become established. This rate of progress is influenced mainly by the dosage of silica which the lungs receive, and this dos age, in turn, depends upon three variables--the amount of silica in the dust, the quantity of dust in the air, and the length of exposure. Individual idiosyncrasy might be included as a fourth variable; however, little is known of the variations in susceptibility in those exposed to dust. It might well be assumed that similar variables would influence the occurrence of asbestosis. In places where asbestos is mined or fabricated in North America there does not appear to be present the clear-cut clinical picture which is so unescapable in communities with a true silicosis hazard, such as hard-roclc mining communities. It may be that some of the asbestos plants are of too recent origin for the typical effects of a silicate dust to become manifest, but this would not apply to the older mines or to all of the fabricating plants. The industrial health service of the Metropolitan Life Insurance Co. undertook the following investigation during the period from October 1929 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 the United States. 2. Physical examinations of asbestos workers, including X-ray films. 3. A study of dust exhaust systems designed to eliminate asbestos dust. Data on the fabricating plants only are included in this study and are designated in the report as plants A, B, C, D, and E. This is a preliminary report. A more extensive study of the asbestos industry is now under way. DTJST STU D IES 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 breathing levels and in close proximity to the workmen. Both of these forms of apparatus are adapted for this work, as they are 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 prevent the solution of some c which might be present. The i cally driven rotary pump and tl by means of a resistance type of , ter for measuring the pressure the dust collected from a volum The electric precipitator is deiprinciple used for recovering di principle depends on electrifying pass through an electrostatic fu out upon a sheet of celluloid, means of a transformer operating alternating current. Air is draw rotary fan, run by a motor, the meter. Samples of dust brushed from 1 also were secured for chemical an the industrial hygiene laborator, dust counts were made accordii United States Bureau of Mines l Service (1). Particles in size i diameter were counted. Chemical analyses were made according to the accepted standi In the first plant studied (A) in size were counted. It has be silica particles exceeding 10 mie part of a meter or one-thousand diameter enter the lung tissu ; usually are not considered when it appeared from some of the p asbestos particles much larger in decided to count all particles and 10 microns and under.1 Total particles per cubic foot : 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 milli< Although the counts in plant A a * Bamples collected by both the impinger and mlcropbotographs oi these dust particles were enl slide projector, the enlarged particles being measu actual measurement), it was easy to calculate th logaiithmie probability paper, the logarithms of t plotted as-ordinates against the probability of occi 2 encountered is designated as chrysotile and ties of the mineral serpentine, in which it mind that silicosis (and presumably asbesly, taking from 5 to 15 and even 20 or 25 shed. This rate of progress is influenced silica which the lungs receive, and this 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 rht well be assumed that similar variables rence of asbestosis. js is mined or fabricated in North America o be present the clear-cut clinical picture n communities with a true silicosis hazard, communities. It may be that some of the >o recent origin for the typical effects of a manifest, but this would not apply to the ie fabricating plants. service of the Metropolitan Life Insurance .ring investigation during the period from 1931, which included: litions in asbestos mines and mills in Canada along the Atlantic Seaboard in the United ms of asbestos workers, including X-ray aust systems designed to eliminate asbestos g plants only are included in this study and ort as plants A, B, C, D, and E. This is a .ore extensive study of the asbestos industry DUST STUDIES < o/ sampling.--Both the impinger (1) and 2) were used for the collection of air samples levels and in close proximity to the workmen. >paratus are adapted for this work, as they sot up and adjusted for the taking of the level, and are extremely efficient, the dust by aspirating the air and then surface covered by a liquid in a container, lied water, containing 50 percent alcohol to 3 January 4 ,1DJ3 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 the Cottrell precipitator principle used for recovering dusts and fumes commercially. This principle depends on electrifying the dust particles by making theca pass through an electrostatic field and thus causing them to setile out upon a sheet of celluloid. The electrostatic field is set up by means of a transformer operating from the lighting lines on 120 vohs., alternating current. Air is drawn through the apparatus by a s m tl rotary fan, run by a motor, the quantity being measured by a flvm meter. Samples of dust brushed from beams and pipe lines near the ceifeg also were secured for chemical analysis. All samples were shipped "w the industrial hygiene laboratory of the Metropolitan Co., and toe dust counts were made according to the methods accepted by rite. United States Bureau of Mines and the United States Public Hcitori Service (1). Particles in size up to 360 microns in the greatest diameter were counted. Chemical analyses were made for total (free and combined) sriesaccording to the accepted standard method of Hillebrand (3). In the first plant studied (A) only particles 10 microns and inulinr in size were counted. It has been demonstrated repeatedly thai auo silica particles exceeding 10 microns (a micron equals one-millksifih part of a meter or one-thousandth part of a millimeter) in greatest diameter enter the lung tissu ; for this reason, the larger partrefies usually are not considered when determining dust counts. Lat&\ as it appeared from some of the published articles (4) (English) dlkat asbestos particles much larger in size were found in lung tissue, i t '.was decided to count all particles and make differential counts of all tkose 10 microns and under.1 Total particles per cubic foot and the corresponding weight of rihe dust in milligrams were obtained. Since no relationship between, the dust counts and the corresponding weights was found, the wehfe.ts are not included in the tabulations in this report. Table 1 shows by plants and by departments the maximum aaad minimum dust counts in million particles per cubic foot of air. Although the counts in plant A are of particles 10 microns and undhr, 1Samples collected by both the impinger and the electric precipitator were counted. In addh.oj^ microphotographs of these dust particles were enlarged by being projected upon a screen with a lamcov shde projector, the enlarged particles being measured with a ruler. Knowing the entire enlargermnu /'g actual measurement), it was easy to calculate the original particle size (5). By the use of HazciA tft; logarithmic probability paper, the logarithms of the function to be measured (in this * -- ' Plotted as ordinates against the probability of o c a n w 'M -- * 4 and in the other plants are for all particles, direct comparison is possible, as in no sample taken were the number of particles 10 microns and under less than 94 percent of the whole. T a b l e 1.-- M aximum and m inim um dust counts in million particles per cubic foot of air, by plant and department Plant A Plant B Plant C Plant D Plant E Department Num ber of sam ples taken Million parti cles under 10/* per cubic foot of air Num ber of sam ples taken Million parti cles per cubic foot of air Num ber of sam ples taken Million parti cles per cubic foot of air Num ber of sam ples taken Million parti cles per cubic foot of air Num ber of sam ples per cubic foot of air Million parti cles per cubic foot of air Preparation................... Card room..................... Ring frame spinning Mule spinning_______ Weaving........................ Felt department........... Sheet insulating............ Molded brake band 5 H -m 3 2 H- 2 %~2H 10 J'i-Hi 4 Ho~2 6 &-UH 3 a-i 1Included in spinning. 9 h -s 5 H-iH 5 H-l () 4 8 2 -43 6 2 H -15H 3 m - os 8 >i - m 6 3?i-10 15 1 -7 2 Hr H *Includes broad loom weaving. 3 30 -82 3 2G -70 3 &v>-m 3 -6V3- 7 3 lOjdHOM Whereas the dust in the preparation room is practically all due to asbestos, the contrary is the case in the other departments. In the I carding, spinning, and weaving 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 25 percent of the tola! material. The actual exposure to asbestos dust, therefore, is consid erably less than is indicated in the dust counts in table 1. CONDITIONS IN TH E 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 passingthrough the opener, the material is discharged into trucks. Waste manufacturing material is first run through a garnet machine and it discharged into trucks, which are material is fed into these in the sa: After being discharged from the c vibrating or shaking screen, when a suction hood and blown into a The short fibers falling through th used in making an asbestos cement The cotton is received in bale vertical openers. It is discharged i the vertical and horizontal opene fiber, the cotton, or the waste mat', bins. As needed, these materials ; floor in proportion to the mixture materials are then passed through is discharged from the picker, it is The material is then taken by a m bin in the card room. Two of tin this conveyor system, wliile a th suction device which conveys the card room. The object of the two s. of two grades of material at the s not equipped with an oil spray. T marily to entrap the small asbesto in the cotton fiber throughout the i weaving. Incidentally, it is appa amount of dust. The material is s oil at this point; but by the time diminished to less than 1 percent. While mineral oil was used in th apparently was not as efficacious a: not used, nor was there any attemp of dust exhausting. Carding mackii there was a humidifying, ventilat plant B depended on natural huri machines were equipped with a dm efficiently used. In plant C cardii which was equipped with an air-ct buildings the machines had exhaust Two plants, B and C, had artifiei spinning rooms. In the former the humidity 78 percent. One plant, C the twisting department and also in the relative humidity was 76 percen 69 F., as compared with a relativ weaving room of plant A. e for all particles, direct comparison is taken were the number of particles 10 n 94 percent of the whole. turn dust counts in million particles per cubic foot by plant and department Plant B Plant C Plant D Plant E sinn er of 'cimfri-JS aicen Million parti cles per cubic foot of air Num ber of sam ples taken Million parti cles per cubic foot of air Num ber of sam ples taken Million parti cles per cubic foot of air Num ber of sam ples per cubic foot of air Million parti cles per cubic foot of air 9 M-8 5 5 H~i 0) 4 H- H 8 2 -43 6 3-15L. 3 Va - 4H> 8 *1 - 3^4 6 3^4-10 15 1 -7 3 3 2G -7t> 3 3 I0h-19% 2 n- % 1Includes broad loom weaving. preparation room is practically all due to le case in the other departments. In the iving rooms asbestos comprises about 25 .sed. On special jobs the percentage of it in general the figure quoted is approximaterial consisting principally of cotton, cuts of plant A, asbestos is but 5 percent . In the molded brake-lining and clutch os comprises about 25 percent of the total sure to asbestos dust, therefore, is considd in the dust counts in table 1. HONS IN THE PLANTS hints were very similar to those in cotton ration, the process in the preparation room at length: igs. These are emptied upon the floor and ito pug mills and run for about 5 minutes n the fibers. From there the asbestos is svheeled to hoppers with either horizontal to those used in textile mills. After passing naterial is discharged into trucks. Waste first run through a garnet machine and discharged into trucks, which are 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 are picked off by a suction hood and blown into a bin to be used again in textiles. The short fibers falling 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 are taken to separate storage bins. As needed, these materials are weighed and dumped onto the floor in proportion to the mixture desired, and the 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 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 also 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 1 percent. While mineral oil was used in the preparation room of plant C, it apparently was not as efficacious as in plant B. 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 there was a humidifying, ventilating, and heating system, while plant B depended on natural humidity. In plant E the carding machines were equipped with a dust-exhaust system, but it was not efficiently used. In plant C carding was done in 2 buildings, 1 of which was equipped with an air-conditioning system, and in both buildings the machines had exhaust equipment. Two plants, B and C, had artificial humidity installations in their spinning rooms. In the former the temperature was 76 F., relative humidity 7S percent. One plant, C, had a humidification system in the twisting department and also in the weaving department, where the relative humidity was 76 percent with a dry-bulb temperature of 69 F., as compared with a relative humidity of 44 percent in the weaving room of plant A. O Aside from plant E, it would appear that the dust hazard was not excessive except in the preparation rooms of plants B and C. The dust counts are interesting, too, when considered in the light of the 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, we are not justified in assuming that because available information suggests that asbestosis is a milder disease clinically than silicosis, the threshold of permissible dust counts is higher. Asbestosis appears to be patho logically different from silicosis, and the experience so far does 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 was 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 was 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 as will make the air entirely dust free. The normal defensive mechanism of 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 this 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 by dust counts. This practice will result in saving a needless expenditure of money. PHYSICAL EXAM INATIONS X-ray films were made of 126 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 having 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 field, a minor nature, and there was gc The films were read conservative examination and the age of ti positive only when there Avas no were guided by their experience moconioscs. The films classed a subdivided into doubtful am whether the individuals classed ; definite asbestosis. Particular at or absence of indications of tube reviewers of the films were in an of silicosis in mind, it was felt devoted to ascertaining, if possi disposes to tuberculous infection. The cases of asbestosis were < and second stage. The first st X-ray examination definite lunwarrant a diagnosis of pneumo< symptoms. The second-stage < pathology and also definite'symp All these individuals 2 were ae it was not practicable to make an ability or disability. Had any in extensive pulmonary involveme or total disability, they would 1 but no such cases were found. Of the total of 126 X-ray c second-degree asbestosis, 63 as fii negative. There is a definite increase in t in relation to the years of exp< numbers make it impossible to c enters into this increase. T able 2.-- ClassiftcaU Years of exposure Over 15 years............. 10 to 15 years_______ fi to 10 years............... Under 5 years............ Total examined. 1Part time. *One asbestos worker (second stage) retired of hi to this study, but is still active about his garden. i 6 .ould appear that the dust hazard was not eparation rooms of plants B and C. The r, too, when considered in the light of the granite dust, established by the United ice (7), namely, about 10 million particles cubic foot. However, we are not justified available information suggests that asbesciinically than silicosis, the threshold of higher. Asbestosis appears to be pathoicosis, and the experience so far does not cfine a standard of dustiness for asbestos DUST CONTROL 5 oiling, humidification, and local exhausts, Nevertheless, it was evident that they :1. If it is expected to control dustiness in must rest upon properly constructed exhaust t one department an experimental installaof 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 illy desirable to install such equipment as lust free. The normal defensive mechanism t fair amount of atmospheric pollution. It d to an excessive amount of dust that this down. ust equipment to textile machinery involves >ecially where the construction of the plant le to apply down-draft suction to the looms, exhaust apparatus in any plant on an exl then check its efficiency by dust counts, n saving a needless expenditure of money. SICAL EXAM INATIONS f 126 persons (108 men, 18 women) working United States. All but five of these were >n. The cases were selected more or less lose haring more than 3 years of empioywas soon obvious that the early diagnosis i a large extent on X-ray pictures of the iages of silicosis, the clinical symptoms of >usually indefinite and inconclusive. The fins are based on the readings of one comut they have been reviewed by several 7 January i, 1935 others experienced in this field. The differences of opinion were of a 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 and other types of pneu moconioses. The films classed as negative for asbestosis were further subdivided into doubtful and negative. Only time can tell whether the individuals classed as doubtful are progressing toward a definite asbestosis. Particular attention was 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 be devoted to ascertaining, if possible, whether or not asbestosis pre disposes to tuberculous infection. The cases of asbestosis were divided into two classes, first stage and second stage. The first stage embraces those who show by X-ray examination definite lung pathology sufficient in extent to warrant a diagnosis of pneumoconiosis, but who have no definite symptoms. The second-stage cases exhibit more extensive lung pathology and also definite symptoms. All these individuals 2 were actively engaged in factory work, and it was 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 stag#:, but no such cases were found. Of the total of 126 X-ray examinations, 4 were diagnosed xs, second-degree asbestosis, 63 as first degree, 39 as doubtful, and 20 its negative. There is a definite increase in the percentage diagnosed as 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 a b l e 2.-- Classification of cases by years of exposure Years of exposure Percentage positive Positive Number Doubtful Negatiwi 87 13 i 1 58 7 3 2 50 30 25 3 43 17 10 67 39 i Part time- 31 not continuous. 3One asbestos worker (second stace) rctred of Ins own accord, because of old age, 10 years previous to this study, but is still active about his garden.  >!@1 flu? 64 persons given physical examination and diagnosed as iiitvng; positive asbestosis, only 8 were entirely free from symptoms, tvikiff 1.9 out of 37 with doubtful and 7 out of 20 with negative diagjmsisK were free from symptoms. Dyspnoea and cough were the -frapfeifns most complained of, but none of these cases exhibited the JtvgHnAOBevident type of " short wind" seen in true silicosis. Several fdka classed as negative stated that they were " short winded" 'STisS. w:.J8 so recorded, but too much emphasis should not be placed aw .-Hiiitftements of subjective symptoms. During the progress of the ,stsuijpr., physicians who were practicing in the communities where workers lived were questioned and stated that they did not frail sm unusual amount of tuberculosis among these workers. The isnataiasst between tliis state of affairs and that found in a community msilicosis hazard is noteworthy. The (incidence of tuberculosis (based upon X-ray films) is given in iiadik- 3; 40 of the 67 examined had less than 15 years of employiHfsirt sin the industry. T a b l e 3.-- Incidence of tuberculosis Positive Doubtful Negative 7 1 2 11 0 67 39 1 OIiU 'Case was diagnosed as probably active on the X*ray findings. 4 gives information as to physical signs of chest trouble. T a b l e 4 .-- Chest findings Positive Doubtful Ncgam c i 33 31 28 13 3 2 0 Diial............................................................................................ 67 39 ' til inist 6 of these showed no evidence associated with asbestosis. `''AaM.ihese not associated with usual signs found with asbestosis. 3d ohiitese not associated with usual signs of asbestosis. What significance, if any, can be attached to the presence of "``aktestos corns" on the hands of workers appears doubtful, as IS permit of the positives (12 out of 64) and 15 percent of the others .kisssstful, 7 out of 37, negative, 2 out of 20) showed such corns. Each roentgenologist who reviewed the X-ray films called attention she fact that these films indicated a very unusual incidence of ffiijbajgement of the hqart. It is probable that this is a compensatory lEkujgement due to the additional work put upon the heart in efforts to pump blood through the fibre sufficient attention has been paid i upon the heart. Many workers had changed fix from one plant to another during asbestos industry. Since only tli time of this survey in the variou no way of knowing the average inhaled by these people over the \ quently, it is not possible to con amounts of dust exposure. IN SU iU X To throw light on the relations nary tuberculosis, an analysis of manent disability claims was mm group insurance and having avail. There were 2,099 lives involved years. The death claims are so elusions cannot be reached from a same is true of the sickness cla number of claims for respiratory < studied but low for the others, a experience of 1927. However, di: first, part of 1929 there was an epic The records of one establish rr; death claims and 8 of 10 permam listed as due to pulmonary tuben ordinate amount of tuberculosis f the employees were Negroes, and ally high in tliis section of the c diagnosing pneumoconiosis and tuberculosis, these claims were su who had treated the individuals and sanatorium records, inchn investigated, with the following n Death claims: 1. A typist, not exposed intestinal tuberculosis. . 2. Colored male, age 27; months; died of pulmonary t was in sanatorium 10 monk mann. No evidence of asbe 3. Colored male, age 32; v 7 months; died of pulmom hospital. Cavitation both k ven physical examination and diagnosed a3 is, only 8 were entirely free from symptoms, doubtful and 7 out of 20 with negative diagymptoms. Dyspnoea and cough were the ned of, but none of these cases exhibited the f " short wind" seen in true silicosis. Several .tive stated that they were " short winded" ut 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 tte of affairs and that found in a community noteworthy. eulosis (based upon X-ray films) is given in :amined had less than 15 years of employ- : 3.-- / ncithmce of tuberculosis Positive Doubtful Negative 7 1 2 i 1 0 1 67 39 20 iy active on the X-ray fnidmps. ion as to physical signs of chest trouble. 'able 4.-- Chest findings Positive Doubtful Negative ` 33 29 37 31 28 13 3 2 0 67 39 20 nee associated with asbestosis. ^sns found u uh asbestosis. burns of aaoestosis. any, can be attached to the presence of hands of workers appears doubtful, as 18 T2 out of 64) and 15 percent of the others gative, 2 out of 20) showed such corns, ho reviewed the X-ray films called attention 1ms indicated a very unusual incidence of It is probable that this is a compensatory Iditional work put upon the heart in efforts 9 January 4 ,163S to pump blood through the fibrosed lungs. It is possible that not sufficient attention has been paid to the effects of the pneumoconioses upon the heart. Many workers had changed from one department to another and from one plant to another during their years of employment in the asbestos industry. Since only the amounts of dust collected at the time of this survey in the various departments are known, there is no way of knowing the average amount of dust in the atmosphere inhaled by these people over the years of their employment. Conse quently, it is not possible to correlate individual cases with definite amounts of dust exposure. IN SU R A N C E CLAIMS To throw light on the relationship between asbestosis and pulmo nary tuberculosis, an analysis of death claims and total and per manent disability claims was made in regard to companies carrying group insurance and having available figures. There were 2,099 lives involved, with a total exposure of 7,019 lifeyears. The death claims are so small in number that reliable con clusions cannot be reached from any subdivision of the figures. The same is true of the sickness claims under health insurance. The number of claims for respiratory diseases is high in two of the plants studied but low for the others, as compared with the Metropolitan experience of 1927. However, during the latter part of 1928 and the first part of 1929 there was an epidemic of influenza. The records of one establishment (plant B) showed that 6 of 38 death claims and 8 of 10 permanent and total disability claims were lifted ns due to pulmonary tuberculosis. This appeared to be an in ordinate amount of tuberculosis from this plant. However, many of tlie employees were Negroes, and also tuberculosis claims are gener ally nigh in this section of the country, localizing the difficulty in diagnosing pneumoconiosis and the tendency to confuse it with tuberculosis, those claims were studied individually. The physicians who had treated the individuals were interviewed, and the hospital end sanatorium records, including available X-ray films, were investigated, with the following results: hath claims: 1. A typist, not exposed to dust; died of pulmonary and intestinal tuberculosis. 2. Colored male, age 27; worked in asbestos 1 year and 8 months; died of pulmonary tuberculosis following a hemorrhage; was in sanatorium 10 months. Also had a four plus Wasserniann. No evidence of asbestosis. 3. Colored male, age 32; worked in asbestos plant 1 year and 7 months; died of pulmonary tuberculosis after 1 month in hospital. Cavitation both lungs; no evidence of asbestosis. if 'if>-tf-. i ;l i ; g,- ) .V J 4<V 4 . Colored male, age 34; worked in asbestos plant 2 years and 6 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 the other two cases. Total and permanent disability claims: 1. Male, employed in asbestos plant 3 years. His physician states that he first came under his observation with an old estab lished case of tuberculosis about 2 years after asbestos employ ment started. Also had tuberculosis of the kidney and cervical glands. 2. Male, employed in asbestos plant 8 months. His 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 asbestos plant. Is now in sanato rium. An interesting case. His physician states that he has ex tensive asbestosis and pulmonary tuberculosis; cavity in right lung; sputum loaded with tubercle bacilli and asbestos bodies; believes tuberculosis long antedated asbestosis. This patient is progressing in a satisfactory manner. It was not possible to locate the other three cases of total and permanent disability who had been diagnosed as having pulmonary tuberculosis. On the basis of the information obtained, the deaths in death-claims cases appear to be due to uncomplicated tuberculosis; three of them were Negroes, who were probably tuberculous at the time their employment in the asbestos plant commenced. Of the 8 disability claim cases, 1 was uncomplicated tuberculosis and 2 were uncomplicated a.sbestosis who were put on disability because of a mistaken diagnosis of tuberculosis. In this same com munity we know of one death due to uncomplicated asbestosis in an individual with many years' employment in the industry.3 C O N C L U SIO N S 1. Prolonged exposure to asbestos dust caused a pulmonary fibrosis of a type different from silicosis and demonstrable on X-ray films. Clinically, from this study, it appears to be of a type milder than silicosis. 2. Cases of definite cardiac enlargement were frequently found to be associated with asbestosis. $Personal communication. 3. A predisposition to tuberc indicated in this study. 4. Asbestosis as observed in t marked disability in any case. 5. It is not known how much of pneumonia and acute nontub 6. It is not practicable as yet t dust content of air. 7. The amount of dust in the ; be substantially reduced. RECOMX It is recommended-- 1. That the industry seriousljasbestos 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, thk examination of the chest. 4. That the industry sponsor s as well as studies on effects of ash ACKNOWl The authors wish to express tl. aided in making this study possi ployees of the asbestos companies and gave every facility for securin University of Pennsylvania, for 1 interpreting X-ray films, and to I States Public Health Service, sun Bureau of Mines Cooperative Ci pretation of all the X-ray films lis preciation is also expressed to Dr. Lynch, of Charleston, S. C., for in as to the pathology of asbestosis;4 S. C.; to Dr. Joseph H. Wyatt, Fellows, of New York, for assisti; Dr. Paul O. Snoke, of Lancaster, Danville, Quebec, Canada; and to E. Cummings, of the Saranac Lab study of the pathological effects < *Asbestosis bodies in sputum and lung. By en n Jour. Am. Med. Assoc., Aug. 3G, 1930, vol. 95, no. 9, i 10 age 34; worked in asbestos plant 2 years and ysician believes this was a case of uncoms. Was not inmate of hospital or sanatorium, ild be obtained on the other two cases. 'sability claims: d in asbestos plant 3 years. His physician ame under his observation with an old estabeulosis about 2 years after asbestos employ- had tuberculosis of the kidney and cervical d in asbestos plant 8 months. His physician lfibroid tuberculosis with tubercle bacilli in available; but according to physician, asound in sputum. ' employment. Two physicians who treated s are now inclined to believe this man is not ' asbestosis. is reexamined at time of investigation. His -'ll nourished, husky looking, good color, no g of fingers; diminished expansion; incessant s fine mottling disseminated through both of tuberculosis. Probably a second stage years in asbestos plant. Is now in sanatoXcase. His physician states that he has exid pulmonary tuberculosis; cavity in right i with tubercle bacilli and asbestos bodies; long antedated asbestosis. This patient is factory manner. locate the other three cases of total and >had been diagnosed as having pulmonary s of the information obtained, the deaths in r to be due to uncomplicated tuberculosis; oes, who were probably tuberculous at the the asbestos plant commenced, m cases, 1 was uncomplicated tuberculosis 'd asbestosis who were put on disability gnosis of tuberculosis. In this same com'ath due to uncomplicated asbestosis in an s' employment in the industry.3 c o n c l u s io n s ) asbestos dust caused a pulmonary fibrosis licosis and demonstrable on X-ray films. ", it appears to be of a type milder than iac enlargement were frequently found to is. 11 January 4,1833 3. A predisposition to tuberculosis due to asbestos dust was not indicated in this study. 4. Asbestosis as observed in this series of cases 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 nontuberculous pulmonary infections. 6. It is not practicable as yet to establish standards for the asbestos dust content of air. 7. The amount of dust in the air in the asbestos plants studied can be substantially reduced. RECOM M ENDATIONS It is recommended-- 1. That the industry seriously face the problem of dust control in asbestos plants. 2. That new employees be examined plij-sically, including X-ray examination of the chest, and rejected for employment if they show tuberculosis or pneumoconiosis. 3. That employees be examined physically, preferably every year, but at least every 2 years, this examination to include an X-ray examination of the chest. 4. That the industry sponsor studies on known cases of asbestosis, as well as studies on effects of asbestosis on the heart and circulation. ACKNOWLEDGMENTS The authors wish to express their sincere 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. Pancoast, of the University of Pennsylvania, for his interest and valuable advice in interpreting X-ray films, and to Dr. F. V. Meriwether, of the United Matas Public Health Service, surgeon in charge of the United States Bureau of Mines Cooperative Clinic in Picher, Okla., whose inter pretation of all the X-ray films listed in this report is followed. Ap preciation is also expressed to Dr. W. Atmar Smith, and Dr. Kenneth Bynch, of Charleston, S. C., for information and advice, particularly as to the pathology of asbestosis;4 to Dr. W. W. Wild, of Charleston, B. C ; to Dr. Joseph H. Wyatt, of Newark, N. J., and Dr. H. H. fellows, of New York, for assisting in interpreting X-ray films; to Ur- Paul O. Snolce, of Lancaster, Pa.; to Dr. R, H. Stevenson, of Danville, Quebec, Canada; and to Dr. L. U. Gardner and Mr. Donald h- Cummings, of the Saranac Laboratory, who have undertaken the Dudv of the pathological effects of the inhalation of asbestos dust ` Asbestosis bodies in sputum and lung. By Kenneth M. Lynch, M. D., and W. A c~ Jour- Am. M ed. Assoc , Aug. 30,1930, vol. 05, no. 9, pp.