Document G5LN0y7ngQrQmawJJpRGk2d2v

FILE NAME Owens Corning OC DATE 1935 Jan 4 DOC OC056 DOCUMENT DESCRIPTION Effects of the Inhalation of Asbestos Dust on the Lungs of Asbestos Workers Tot . oe, Neem a, 9 ete see ee . 7 { | | | U.S. TREASURY DEPARTMENT HENRY MORGENTHAU J. Secretary _ PUBLIC HEALTH SERVICE BUGE S. CUMMING Surgeon General | | | EFFECTS OF THE INHALATION OF |; ASBESTOS DUST ON THE LUNGS i OF ASBESTOS WORKERS BY ] t i} A. J. LANZA | _ Assistant Medical Director . t WILLIAM J. MCCONNELL | Assistant Medical Director j | AND J. WILLIAM FEHNEL Chemist { Metropolitan Life Insurance Co. f | REPRINT No. 1665 | | FROM THE PUBLIC HEALTH REPORTS VOL 50 No. 1 JANUARY 4 1985 | | Pag 1-12 | | CORNING FIBERGLAS CORP LEGAL & PATENT DEPT REC'D SEP 15 1941 UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1985 Form Form by the Buperintendent of Documenta Washington C eee el. Drie 4 eens dad as tT Sa ot Fan ' 1 OF ASBESTOS DUST ON EFFECTS OF THE INHALATION THE LUNGS OF ASBESTOS WORKERS Preliminary Study WILLIAM J. MCCONNELL Assist- By A. J. LANZA AssistanatndMeJd.icWailllDiiraemctoFrehnEL Chemist Metropolitan Life ant Medical Director - INTRODUCTION Insurance Co. a pneumoconiosis Life Insurance Co. was approached by In 1929 the Metroptohleitasabnestos industry in the United States who an occupa officials representing whether asbestos dust was desirous of ascertaining the nature were in their establishments and if so what was tional hazard or control it . of this hazard and what should be done to prevent in English medical several articles had appeared While in About this time due to asbestos dust journals describing a of this type of pneumo- one or two isolated instancesinthAemeocrciucrarnenjcoeurnals the industry itself such coniosis had been describuendinformed of the existence of any appeared to be quite occupational disease reference to the lungs has The hazard of silica dust with special and research has long been appreciated and a great deal of study and certain other been applied to the problem in the metal mining Britain the United States the British Doeffects of silica industries in Great and in other countries The nature of the extraor- orm minions silicosis with the resultant dust expressed in the term tuberculosistuberculosis is well known we dinary predisposition to pulmonary the inhalation of dust con- These effects have been associaatmeodunwittsh The effects upon the pul- taining free silica in varycionngtaining combined silicates monary tissue of dusts but evidence is accumulating that e still a fertile field for investigation distinct from certain of these dusts produce pathological results quite eR FHeONG pneumocoBnincatie osis HOA true silicosis has been applied to the The name asbestosis will be so used in this report Chem caused by asbestos dust and it is a hydrated magnesium Bincate ically the asbestos of commerce silica 44.1 percent hug consisting primarily of silica combined while ferrous iron and nesia 43 percent and water 12.9 percent commercial variety of BENT quantities This TR nickel are present in small t omy E B hadirerg e =e apLh, y sEoSe e TERR go Ce ar Stay) on eI ae, E rv P ay.ye TONE aE ciepew ar ee one oe ompenye Ease eaty, Mer een.< 8 Recs 2 EFFECTS OF ASBESTOS DUST ON THE LUNGS asbestos most commonly encountered is designated as chrysotile and is 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 a Des- : tosis develops very slowly taking from 5 to 15 and even 20 25 to become established This rate of progress is influenced years mainly by the dosage of silica which the lungs receive and this dosage in turn depends upon three variables 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 clinical picture which is so unescapable in communities with a true silicosis hazard such as hard 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 in " 1. study of dust conditions in asbestos mines and mills Canedo and in fabricating plants along the Atlantic Seaboard in the United . States a . , 2. Physical examinations of asbestos workers including ray 3. A study of dust exhaust systems designed to eliminate asbestos dust . the fabricating plants only are included in this study and .Data on are designated in the report as plants A C D and E. This is a preliminary report A more extensive study of the asbestos indust is now under way a DUST STUDIES oa , "a impinging Apparatus and methods of sampling 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 it onto a flat surface covered by a liquid in a container iTmhpiengilnigquid used was distilled water containing 50 percent alcohol to 3 OS Pt lank ep tette cbee vis \ _= en cenCMRLET eer RONEN Sea ke rete hpige ages we, * - 24. Se han:ete ee 2 SPE rete 3 o . anys 8 = Ey & 4 wale, perth EFFECTS OF ASBESTOS DUST ON THE LUNGS 3 prevent the solution of some of the dusts particularly any silica which might be present The impinger was actuated by an electrically driven rotary pump and the rate of air sampled was measured by means of a resistance type of flow meter with an inclined manometer 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 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 through 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 size up to 360 microns in the greatest diameter were counted Chemical analyses were made for total free and combined silica under f according to the accepted standard method of Hillebrand 3 In the first plant studied 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 millionth part of a meter or thousandth part of a millimeter in greatest diameter enter the lung tissu ; for this reason the larger particles usually are not considered when determining dust counts Later as it appeared from some of the published articles 4 English that asbestos particles much larger in size were found in lung tissue it was decided to count all particles and make differential counts of all those 10 microns and under Total particles per cubic foot and the corresponding weight of the dust in milligrams were obtained Since no relationship between the dust counts and the corresponding weights was found the weights are not included in the tabulations in this report Table 1 shows by plants and by departments the maximum and minimum dust counts in million particles per cubic foot of air Although the counts in plant A are of particles 10 microns and under i Bamples collected by both the impinger and the electric precipitator ware counted In addition microphotographs of these dust particles were enlarged by being projected upon a screen with a lantern- alide projector the enlarged particles being measured with a ruler Knowing the entire anlargament by actual measurement it was easy to calen theioa rit gie na particis gisa 5 By the cams of Hazen'ness Logarithmic probability paper the logarithms of the function to be measured in this case micronnses plotted as ordinatas against the probability of cocurrence an abe time ee ss EFFECTOSF ASBESTOS DUST OK THE LUNGS 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 = -) a) - 7 Hoye r Table Mar^>mumand minimum dust counts in million particles per of air by plani and department , : cubic foot Plant & Plant B Plant C J Plant D Plant E . Milion Milhon Million Million Nam- | Num | parti Nbeur m cles per } | cies per Department bes cles ber | of parti parti Num- Num- of Milhon Num parti of Million Num- parts . be of Million ber of F.D- pias Milhon Milhon ples cubic | 1u0nd...epre per 1 | | 88 33 cubic 1820- cubic per cuble : pies cubic ples foot of ples foot of foot of cubic foot of 7 | | ] | fot | taken taken taken | | | taken of as kir taken mir foot air foot foot . .. department Felt department Shee insulating Molded brake band and clutch st 10 #14K 9 & 10 tlhe 5 the 6 2 & ape -% eee war^nn ** war^nn 46-24 6| 20 -1300 420-2 420-2 q| war^nn 420-2 HAnoo war^nn Pee Dee 4) (4) 8 5 15 lowe reefec cence ce [nnn Sere ceesecel-nes eee | 3 844-30 8 07 07 810-19 810-19 comelecewocer[roveecefecesonces a coe ctecresfenccceee en 2| } * Included in spinning Includes broad loom weaving Whereas 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 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 lining a and clutch division of plant D asbestos comprises about 25 percent of total 5 therefore is conside material The actual exposure to asbestos dust F erably less than is indicated in the dust counts in table 1 ; CONDITIONS IN THE PLANTS : in The processes in these plants were very similar to those cotton mills in general For illustration the process in the preparation room of plant B is here detailed at length . oe of 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 Ee neoDe ee -- Bere eee 1 art pm, e . EFFECTS OF ASBESTOS DUST ON THE LUNGS 5 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 primarily 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 exhaust system but it was not efficiently used In plant C carding was done in 2 buildings 1 of which was equipped with an 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 78 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 bulb temperature of 69 F. as compared with a relative humidity of 44 percent in the weaving room of plant A. SEMA. BAYER - sa RELA ; RE sete! . ee. eres SRE ee OR. Ye, xe ey Pres te BEE PUR een ae Maly .6 Aside from plant E it would appear that excessive except in the preparation rooms of plants B and The Ss 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 4% i 10 microns and under per cubic foot However we are not justified ~ in assuming that because available information suggests that asbes tosis is a milder disease clinically than silicosis the thresholodf #: ~ permissible dust counts is higher Asbestosis appears to be patho logically different from silicosis and the experience so far does not wy an attempt to define a standard of dustiness for asbestos ge: Sa - ae vo warrant dust DUST CONTROL . Cee samery, exhausta Various measures such as oiling humidification and local tended to reduce the dust Nevertheless it was evident that they were only partly successful If it is expected to ccoonntsrtorlucdtuesdteixnehsasusm2 these plants final reliance must rest upon properly installs ^ equipment In plant C in one department an experiment equipment tion was set up In spite of some obvious faults this percent 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 satisfactorysatisfactory It is neither practicable nor economically desirable to install such equipmentmechanism mechanism will make the air entirely dust free The normal defensive mechanism mechanism of the body takes care of a fair amount of atmospheric pollution is when the body is exposed to an excessive amount of dust that this involve defense mechanism breaks down The application of exhaust equipment to textile machinery involve considerable difficulty especially where the construction of the plant is such that it is not possible to apply down suction to the loom loom It is desirable to install exhaust apparatus in any plant on an t- first perimental basis and then check its efficiency by dust counts needless expenditure of money This practice will result in saving a PHYSICAL EXAMINATIONS working & ray films were made of 126 persons 108Almlebnut18fiwveomofenthese were & in asbestos plants in the United States or less given physical examination The cases were selected more employ at random from among those having more than 3 yeaerasrlyofdiamo - ment in the industry It was soon obvious that the of asbestosis must rest to a large extent on ray pictures : chest As in the early stages of silicosis the clinical symptom The The the asbestos workers were usually indefinite and inconclusive com of these films are based on the readings of one interpretations been reviewed by sever petent roentgenologist but they have a minor nature and there was general The films were read agreement as to interpretation examination and conservatively the taking into account the physical age of the individual and were classed as moconioses The films classed as subdivided into doubtful and negative for asbestosis were further whether the individuals classed negative Only time con ter definite asbestosis as doubtful are progressing toward a Particular attention was focussed on the presence of silicosis in mind it was felt that devoted to a great deal of care should be ascertaining if possible whether or not disposes to tuberculous infection asbestosis pre- The cases of asbestosis and second stage The were first divided into two classes first stage ray examination definite stage embraces those who show by warrant a diagnosis of lung pathology sufficient in extent to symptoms The pneumoconiosis but who have no definite second cases exhibit more pathology and also definite symptoms extensive lung All these individuals * were it was not practicable to actively engageidn factory work and ability or disability Hadmake any distinction on the basis of working extensive any individuals been found who exhibited pulmonary involvement and marked or total disability they would have been physical disability but no such cases were found classified as third stage Of the total of 126 ray examinations 4 ; second asbestosis 63 as first were diagnosed as negative degree 39 as doubtful and 20 as . There is a definite increase in the . in relation to the percentage diagnosed as positive numbers years of exposure as shown in table 2. Sman enters intmo atkhies iitncirmepaossesible to determine how far the factor of age TABLE 2. Classification of cases by years of exposure Years of exposure Percentage Number Positive | Doubtful Negative . time |. his garden O ne asbestos worker second to this study but is still stage retired of his own motiva about 6889 27856 6889 27856 6889 27856 6889 27856 . 27856 . 1 not contignot card beosmas of old age 77828 782 77828 77828 77828 77828 . 10 years 18 2 3 uv ww . previous : : EenGee Read fegecse\iee wei fe eet Fee 2s, Se ees 7 BR, ..< ety 5 ee we Er SLO) rt aay oe eR A hal oe ; Sag SK sN.y " Reig ess ogee Rel SR: pes stn 5 SE aT rns Ee mee Sera Ae auf , se EK ESE rier. | er alee ie?gy hese er CY ' . . .- . - PC ee ae aye 9 . +e elamaratain oot i Pe pele tm N Tae OF . 2 Teen sk ily 2g He a Y 6 PAL : teat 2 a ren { 8 EFFECTS OF ASBESTOS DUST ON THE LUNGS 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 diagnoses 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 were 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 and that found in a community with a silicosis hazard is noteworthy The incidence of tuberculosis based upon ray films is given in table 3 40 of the 67 examined had less than 15 years of employ- . ment in the industry TABLE Incidence of tuberculosis Tuberculosis healed Tuberculosis active Total examined Positive | Doubtful | Negative 11 Bow 20 Pemwemscerecetoe 67 | This case was diagnosed as probably active on the rey Endings Table 4 gives information as to physical signs of chest trouble Table Chest findings Physical signs No physical of chart trouble Not examined . 2. nunc necace Total ' At least 6 of these showed no evidence associated asbestosis with 12 of these not associated with usual signs found with asbestoelS 16 of these not associated with usual signs of asbestosis Positive | Doubtful | Negative 113 99 a9 1 xz 13 3 3 0 @ 27 What significance if any can be attached to the presence of asbestos corns on the hands of workers appears doubtful as 18 percent of the positives 12 out of 64 and 15 percent of the others doubtful 7 out of 37 negative 2 out of 20 showed such corns Each roentgenologist who reviewed the ray films called attention to the fact that these films indicated a very unusual incidence of enlargement of the heart It is probable that this is a compensatory enlargement due to the additional work put upon the heart in efforts . EFFECTS OF ASBESTOS DUST ON THE LUNGS 9 to pump blood through the fibrosed lungs It is possible that not sufficient attention has been paid to the effects of the pneumoconoses 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 INSURANCE CLAIMS To throw light on the relationship between asbestosis and pulmo- nary tuberculosis an analysis of death claims and total and permanent 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 life- years The death claims are so small in number that reliable con- clusions cannot be reached from any subdivision of the figures same is true of the sickness claims under health insurance The 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 36 death claims and 8 of 10 permanent and total disability claims were listed as due to pulmonary tuberculosis This appeared to be an in- ordinate amount of tuberculosis from this plant However many of the employees were Negroes and also tuberculosis claims are gener- ally high in this section of the country Realizing the difficulty in Sa diagnosing pneumoconiosis and the tendency to confuse it wit tuberculosis these claims were studied individually The physicians who had treated the individuals were interviewed and the hospital and sanatorium records including available ray films were investigated with the following results Death claims died 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 Wasser- mann 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 - - fe 10 EFFECTS OF ASBESTOS DUST ON THE LUNGS serene physician 4. Colored male age 34 worked in asbestos plant 2 years and 6 months His 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 ment _ 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- started Also had tuberculosis of the kidney and cervical glands oo, 2. Male employed in asbestos plant 8 months His physician states finding of old fibroid tuberculosis with tubercle bacilli in sputum No ray available but according to physician 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 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 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 asbestosis who were because of a mistaken diagnosis of tuberculosis put on disability In this same com- munity we know of one death due to uncomplicated asbestosis in an individual with many years employment in the industry CONCLUSIONS _ pulmonary Horosis 1. Prolonged exposure to asbestos dust caused a of type different from silicosis and demonstrable on 135 Clinically from this study it appears to be of a type milder silicosis cardiac enlargement " filnts than 2. Cases of definite cardiac enlargement were frequently found to be associated with asbestosis . bey: mo Personal communication re ae rs EO a rev ^'s. PTEBahai f | f \ {. i ' ly ' FS EFFECTS OF ASBESTOS DUST ON THE LUNGS 11 3. A predisposition to tuberculosis due to asbestos dust 7 indicated in this study was not 4. Asbestosis as observed in this series of cases had marked disability in any case not resulted in . 5. It is not known how much asbestosis of pneumonia and acute may add to the mortality nontuberculous pulmonary infections dus6.t cIot ntennottopfraacitricable as yet to establish standards for the aslestos aslestos 7. The amount of dust in the air in the asbestos be substantially reduced plants studied can RECOMMENDATIONS It is recommended- 1. That the industry seriously face the problem of dust asbestos plants control in 2. That new employees be examined physically including ray etuxbaemricnualtosiiosn oorf ptnheeumcohecsotniaonsdisrejected for employment if they show - 3. That employees be examined physically preferably but at least every 2 years this examination to every year include examination of the chest an ray 4. That the industry sponsor studies on known cases of as well as studies on effects of asbestosis on the heart and caisrbceusltatoisoins ACKNOWLEDGMENTS The authors wish to express their sincere thanks to all those aided in making this study possible especially the officials who ployees of the asbestos and em- companies who cooperated to the fullest extent and gave every facility for securing data also to Dr. University of Pennsylvania for his interest and valPuaanblceoaasdtviocfethine interpreting ray films and to Dr. F. V. Meriwether of the United States Public Health Service surgeon in charge of the United States Bureau of Mines Cooperative Clinic in Picher Okla whose inter- pretation of all the ray films listed in this report is followed preciation is also expressed to Dr. W. Atmar Ap- Smith and Dr. Kenneth Lynch of to the Charleston S. C. for information and advice particularly as pathology of asbestosis to Dr. W. W. Wild of Charleston S. C to Dr. Joseph H. Wyatt of Newark N. J. and Dr. H. H. Fellows of New York for assisting in interpreting ray films to Dr. Paul O. Snoke of Lancaster Pa to Dr. R. H. Danville Quebec Canada ; and to Dr. L. U. Gardner Stevenson of E. Cummings of the Saranac and Mr. Donald Laboratory who have undertaken the study of the pathological effects of the inhalation of asbestos dust Asbestosis bodies in sputum and lung By Kanneth M. Jour Am Med Assoc Aug 30 1930 vol BE no 9 pp 680 Ly8n6c1 h M. D. and W. Atmar Smith M. x oat os rte 12 EFFECTS OF ASBESTOS DUST ON THE LUNGS through animal experimentation with the aid of a grant from the Metropolitan Life Insurance Co. REFERENCES 1 Greenburg Leonard and Bloomfield J. J The impinger dust sampling ap- paratus as used by the United States Public Health Service Pub Health Rep vol 47 no 12 Mar. 18 1932. Reprint no 1528 2 Drinker Philip and Thomson Robert M Determination of suspensoids by alternating precipitators 1925 Jour Ind Hyg vol VII no 6 June 3 Hillebrand W. F The analysis of silicate and carbonate rocks Bull 422 United States Geological Survey Washington D. C. 4 Cooke W. E Pulmonary asbestosis Brit Med Jour Dec. 3 1927 5 Green H A photomicrographic method for the determination of partiz size of paint and rubber pigments Jour Franklin Institute 1921 3 192 637 6 Whipple G. C Vital statistics John Wiley and Sons New York 1925 p 451 7 Russel A. E. Britten R. H. Thompson L. R. and Bloomfield J. .: The health of workers in dusty trades II Exposure to slliceous dust granite industry Pub Health Bull No. 187. 1929 - --