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FILE NAME Brakes BRK DATE 1935 Sept 20 DOC BRK003 DOCUMENT DESCRIPTION PA Dept of Labor Bulletin - Asbestosis COMMONWEALTH OF PENNSYLVANIA DEPARTMENT of LaboR AND INDUSTRY DOCUM DOCUM RALPH M. BASHORE Secretary Special Bulletin ASBESTOSIS Page 12 Page 24 ERRATA Asbestosis Parts II and III Special Bulletin No. 42 Second line change less to greater Third paragraph first line change three to two BUREAU OF INDUSTRIAL STANDARDS JOHN CAMPBELL Director Harrisburg Pennsylvania September 20 1935 COMMONWEALTH OF PENNSYLVANIA DEPARTMENT OF LABOR AND INDUSTRY RALPH M. BASHORE Secretary Special Bulletin No. 42 ASBESTOSIS Part II . Part III The Nature and Amount of Dust Encountered in Asbestos Fabricat- ing Plants The Effects of Exposure to Dust Encountered in Asbestos Fabricat- ing Plants on the Health of a Group of Workers - BUREAU OF INDUSTRIAL STANDARDS a JOHN CAMPBELL Director Harrisburg Pennsylvania September 20 1935 5< COMMONWEALTH OF PENNSYLVANIA DEPARTMENT OF LABOR AND INDUSTRY Asbestosis The Nature and Amount of Dust Encountered in Asbestos Fabricat- ing Plants Part III The Effects of Exposure to Dust Encountered in Asbestos Fabricating Plants on the Health of a Group of Workers by of WILLIAM B. FULTON M. Chief Industrial Hygiene ALLAN DOOLEY DOOLEY Chemist JULIA L. MATTHEWS PH D. Chemist ROBERT L. HOUTZ Chemist INDUSTRIAL HYGIENE BUREAU OF INDUSTRIAL SECTION STANDARDS ASBESTOSISEncount In 1934 the Dep wealth of Pennsyl to the health of we Pennsylvania Th of the literaturea the general subje lack of information their cooperation include an evaluat gree of dustiness agreement was neither would be ings of any partic employes in thi being recorded of the Departmet Asbestosis was 16 at the Char in 1924 reported dergrass 83 in ers Since then of asbestosis bu 74 publishetd ers together with McConnell and report of a com The industry plants engaged sulating tape asi ucts According there are approx facture of asbest The nature or procedures used accepted standa ing and particl report 41 the countered in th * of Samples dustU modified form of medium In this ma distilled water was and made counting p of at least thirty p field remained consta of leather straps in ANIA INDUSTRY int of Dust os Fabricat re to Dust os Fabricat- 1 ofaGroup of Industrial Hygiene ast TION NDARDS ASBESTOSIS II The Nature and Amount of Dust Encountered in Asbestos Fabricating Plants INTRODUCTION INTRODUCTION In 1934 the Department of Labor and Industry of the Commonwealth of Pennsylvania received a request for information relative to the health of workers employed in asbestos fabricating plants in Pennsylvania The Department had no data available and a review of the literature at that time revealed a scarcity of information on the general subject of asbestos pneumokoniosis Because of this lack of information the industries in the State were consulted and their cooperation was obtained to conduct a survey which would include an evaluation of the hazard from the standpoint of the de- gree of dustiness and the physical condition of the workers An agreement was made with the employers and employes that neither would be given specific information as to the physical find- ings of any particular workman and that the original identity of all employes in this study would be destroyed case numbers only being recorded All records obtained were to become the property of the Department of Labor and Industry Asbestosis was first recognized clinically by Dr. H. M. Murray 16 at the Charing Cross Hospital London in 1900. Cooke 16 in 1924 reported a case of pulmonary asbestosis Pancoast and Pen- dergrass 83 in 1926 examined a group of seventeen asbestos workers Since then other investigators have reported individual cases of asbestosis but it was not until 1930 that Merewether and Price 74 published the results of a study on a group of asbestos workers together with some evaluation of the degree of exposure Lanza McConnell and Fehnel 66 have recently published a preliminary report of a comprehensive survey on this subject The industry in this State consists mainly of several fabricating plants engaged in the making of asbestos cloth brake lining insulating tape asbestos rope and wick and other miscellaneous prod- ucts According to the 1931 Pennsylvania Industrial Directory 61 there are approximately two thousand persons engaged facture of asbestos products in Pennsylvania The nature of asbestos dust is such that many of in the manuthe standard procedures used for other dusts could not be used Changes in the accepted standard method were required in the collection count- ing and particle size determination of the dust In Part I of this report 41 the method of collection and counting of dust en- countered in this study was described and summarized Samples of dust taken in plants for fabricating asbestos products were collected by a modified form of the standard method using a wv per cent U. S. P. ethyl alcohol as a medium In this medium the particles were well distributed and readily counted W distilled water was utilized as the collecting medium agglomeration occurred immediately and made counting impossible Dispersion of the dust in alcohol is good A settling time of at least thirty minutes was required before counting The particle count in any given field remained constant after this period A modified holster is described It is constructed of leather straps in such a way that the fluid in the impinger flask is visible at all times 3 dustPreliminary to the collection of atmospheric dust samples in each of the four plants included in the survey general information was obtained concerning all phases of plant hygiene with special refer- ence to the general plan of the factory number and types of opera- tions ventilation of workrooms illumination etc. The concentration of dust in a plant was determined for each operation or department A complete study of each operation was made noting in detail the nature of the work approximate time re- quired for each operation and changes in the process so that sam- ples collected would be representative of the actual the exposure to PROPERTIES OF ASBESTOS The term Asbestos in its commercial sense is loosely applied to a group of minerals with a number of divisions having in common fibrous structure and possessing more or less resistance to the action of fire and acid The three mineral groups are 1. Anthophyllite- Mg.Fe SiO3 Amphibole or Hornblende of Fe Ca Mg 3. Serpentine 3MgO.2SiO2.2H O The three types of asbestos ordinarily used in manufacturing are chrysotile crocidolite and amosite Crocidolite blue asbestos and amosite a yellow or brown variety of crocidolite both the amphibole or hornblende group belong to The principal source of the latter two varieties is at present Rhodesia South Africa tile a mineral of the Chryso- % serpentine of the asbestos of group comprises the bulk about commerce of crocidolite and amosite Only relatively small amounts of are used in comparison to the quantity chrysotile quantity The principal source of chrysotile is the Thetford ada about forty miles south of Quebec region of Can- The United not rank high as a producer of asbestos the domestic States does less than three per cent of the amount used in its asboeusttpoust mbaeniun-g facturing industries 10 No asbestos is mined in although small amounts have been found in Pennsylvania from time to time No serpentine quarries asbestos from the attempt has ever been made to separate the serpentine in these quarries Arizona and Ver- mont supply the bulk of asbestos mined in this country TABLE 1 TYPICAL ANALYSES OF CHRYSOTILE Sample No. Total Total MgO 39.0567 ee 40.07 FeO Os 3.67 ae ; Comb 14.48 | 3 12 41.85 2.60 en ~ 0.82 14.37 5 40.87 41.50 2.81 2.81 0.90 18.55 In the Canadia eighth inch t serpentine rock lustrous color al filaments they a greasy and slippe a single fiber like Chemically chu small amounts of published analys analys they appear to vi of chrysotile 195 does not exist as bases in a comp workers breathi analyzed petrogra The chrysotile depending on the separated unfiberized form mechanical crush aration of the li is 34 inch and l up to 3 inch length The spinning length Consequ from the crude f of textiles and in ter and cement Preparation gone no treatme from the fiber at the plant in The fibers must ticles This ope a preparing ro are opened and fiber is fed inte minutes These radial axle and is placed Afte ciently they ar usually of the S open the fibers a rectangular material and so from the screen then ready for * Petrographic anal Hygiene Laboratory t samples in each information was ith special refer- 1 types of opera- rmined for each li operation was oximate time reess so that samtual exposure to moosely applied to - having in com- ssresistance to ups are . Ca Mg Mg anufacturing are ue asbestos and both belong to al source of the Africa Chrysothe bulk about small amounts to the quantity region of Canited States does tic output being asbestos manu- n Pennsylvania mine quarries to separate the izona and Ver- pA Comb O In the Canadian deposits the chrysotile is found in veins from eighth inch to six inches in length occurring as bands in the serpentine rock The mineral is generally a dark to blackish lustrous color although when the fibers are separated into fine filaments they are white The fibers are very fine silky soft greasy and slippery to the touch a single fiber like cotton or wool They cannot be separated into Chemically chrysotile is a hydrated silicate of magnesium with small amounts of oxides of iron and aluminum There are many published analyses of chrysotile from the Thetford region and they appear to vary but little Table I gives eight typical analyses of chrysotile 95 The silica shown in the analyses in Table I does not exist as free silica It is chemically combined with the bases in a complex molecule Samples of dust collected in the workers breathing zone with the electric precipitator 30 were analyzed petrographically and were found to contain no free silica The chrysotile of commerce is classified in two general grades depending on the length of the fibers Crude fiber consists of the separated and -selected material essentially in its native or unfiberized form Mill fiber includes all grades that are obtained by mechanical crushing of the rock and subsequent mechanical sep- aration of the fiber Crude No. 1 consists of fiber whose length is 34 inch and longer Crude No. 2 ranges in length from 3 inch up to 34 inch Mill fiber includes all fibers less than 34 inch in length The spinning quality of asbestos fiber depends primarily on its length Consequently the best grades of asbestos textiles are made from the crude fiber The shorter fibers are used in cheaper grades of textiles and in the manufacture of asbestos shingles paper plas- ter and cement DESCRIPTION OF PROCESS Preparation fiber as received from the mines has undergone no treatment other than hammering to remove the rock from the fiber after which it is sorted and screened It is received at the plant in burlap bags each containing one hundred pounds The fibers must first be separated and loosened to remove rock particles This operation is done in what is known to the industry as a preparing room A number of bags sufficient for one batch are opened and dumped on the floor of the preparing room The fiber is fed into wheel crushers and crushed for about fifteen minutes These crushers have two heavy rollers attached to a radial axle and revolve on a smooth surface on which the asbestos is placed After the fibers have been crushed and loosened sufficiently they are fed into the hopper of an opener or fiberizer usually of the Lowell type This operation serves to further open the fibers From the opener the asbestos is discharged onto a rectangular shaker screen where small pieces of stone foreign material and some of the dust are removed The asbestos is lifted from the screen by air suction and conveyed to storage bins It is then ready for mixing with cotton Petrographic analyses of samples were conducted by Dr. A. E. Galloway of the Industrial Hygiene Laboratory Pennsylvania Department of Labor and Industry 5 Mill fiber because of the mechanical crushing and separation given it at the mine does not require the preliminary processing in the wheel crushers as does the crude fiber The mill fiber is fed directly into the Lowell opener and from then on is given the same treatment as the crude fiber Asbestos fibers when examined microscopically do not possess the rough imbricated surfaces of other fibers such as wool They resemble fine polished metal rods free from any serrated surfaces This characteristic explains the extreme difficulty encountered in attempting to spin a thread of pure asbestos A certain amount of cotton must be added as a binder for spinning The amount added depends on the type of fiber and the use for which the finished product is intended Table II shows the average amount of asbestos used in the manufacture of products made in the four plants included in this survey is wheeled in ha into the feed hop volving cylinder- loose blanket through ninety d finisher card T finisher onto n scrapers or rubbe unspun yarn T taken to the spir The rovings at spinning purpose are gathered up sequent operatio is shredded and Some cards an TABLE HI PERCENTAGES OF ASBESTOS IN VARIOUS ASBESTOS PRODUCTS* Material Plant .1 Plant 1 Plant C Plant ) corporated into practice vields a In the manni used The rope , Brake lining woven oe.we eee eee ee , are thicker than ~~ 70-75 fi ficient General Insulatitnapge -. 50 80 80-85 manufacture is . Commercial grade yarn Gov't Specif yarn and chutle .. Asbestos rope and wick . Yann and cloth Underwriters Spec Coeeceeesene a 7 ae nese _ coe eM -- _ - , 7 75 90 , ~ an 75-100 7 a ~~ SO . , 5 02-85 Asbestos cements 2222..0222---... Brake lining molded 202. Asbestos paper -.--2-. 20-2 -e ee eee ' magnesia insulation .. Asbestos shingles and juaaber Compiled from information supplied by the manufacturers Weighed quantities of asbestos and cotton and usually some small amounts of card waste are dumped in alternate layers in a pile on the floor of the mixing room directly in front of the mixing picker The batch is shoveled into the picker which is equipped with revolving beaters In order to secure thorough mixing the batch is run through the same picker twice or through two pickers arranged in series The mixture is removed by suction to the storage bins to await caring Carding is necessary to remove the remaining small bits of rock and to comb the fibers into a more or less parallel condition so that they may be spun A card is a machine with a series of revolving cylinders covered with strips of leather wound diagonally and fitted with fine close sharp steel bristles A carding unit as used in asbestos plants usually consists of two cards the breaker and the finisher The mixture of asbestos and cotton Spinning necessarily have is necessary . strength This or on a machine all the spinm plants had spin The mules ha dred and filty which is made from the cards fastened to the spools a maxi maxi are unwound slight twist 1point of greate yarn spun carriage move ing the spun spi dies The fully wound w The duties + the mule who unspun roving constant vigil Subsequent transferred to ply yarn on transfer of the 6 ishing and separation iminary processing in cr The mill fiber is from then on is given cally do not possess such as wool They ny serrated surfaces culty encountered in ^ certain amount inning The amount for which the finished age amount of asbes- le in the four plants ASBESTOS PRODUCTS lant th * . . Plant C 70.7568 80 --- Plant 1 60 ~ 80-95 80-100 75-100 sub . 80 ~ in wu _ ~ 30 -- cotton and usually in alternate layers ectly in front of the the picker which is secure thorough mixor twice or through - removed by suction the remaining small or less parallel con- machine with a series ' leather wound dicel bristles A card- msists of two cards asbestos and cotton is wheeled in hand trucks from the storage bins and fed by hand into the feed hopper of the breaker card It is passed over the re- volving cylinders of the breaker card emerging in the form of a loose blanket or web The direction of flow is then changed through ninety degrees It next passes over a camel into the finisher card The fiber is stripped from the last cylinder of the finisher onto a moving leather apron where a set of reciprocating scrapers or rubbers condenses it into loose rovings or slivers of unspun yarn These rovings are wound on long Jack spools to be taken to the spinning department The rovings at the extreme ends of the cards cannot be used for spinning purposes because of their lack of uniform thickness These are gathered up as card waste and together with waste from subsequent operations returned to the preparing room where the waste is shredded and added to later batches Some cards are designed so that a fine cotton thread may be incorporated into the rovings as they are doffed from the card This practice yields a stronger roving is In the manufacture of asbestos rope and wick only one card is used The rope and wick rovings which are not subsequently spun are thicker than yarn rovings Hence one carding operation is suf- ficient Generally a fiber of shorter staple than that used in textile manufacture is used for making rope and wick Spinning unspun rovings as they are doffed from the cards necessarily have no twist and therefore little tensile strength It is necessary to twist or spin these rovings to impart the desired strength This spinning may be done either on ring spinning frames on machine called a mule In the plants included in this study all the spinning was done by the latter method Several of the plants had spinning frames but they were not in operation The mules had from two hundred and sixty to possibly five hun dred and fifty spindles mounted in a straight line on a carriage which is made to move forward and backward The Jack spools from the cards are mounted on the mule and the ends of the rovings fastened to the spindles As the spindles recede from the Jack spools a maximum distance of about fifty four inches the rovings are unwound The spindles turn slowly as they recede to give a slight twist to the rovings When the spindles have reached the point of greatest recession they are turned very rapidly and the varn spun When sufficient twisting has been done the spindle carriage moves back again in the direction of the Jack spools causing the spun yarn about four inches to be wound on the spindles The operation is then repeated until the spindles are fully wound with single yarn The duties of the mule spinner are to remove the spindles from the mule when they are filled and to tie the broken ends of the unspun rovings as the spindles recede This last operation requires constant vigilence because the rovings are continually breaking Subsequent Operations spindles from the mules are next transferred to a spooling or winding machine to rewind the single- ply yarn on other types of spools transfer of the yarn This is simply a mechanical 7 These spools are next taken to a twisting machine where two or three of the single threads are twisted into one thread For the manufacture of brake lining or packing the inforced with a fine metallic wire This addition ing the twisting operation The twisted yarn is paper spools about six inches long yarn may be re- is performed durfinally wound on The twisted yarn may be sold as such to other manufacturers or it may be woven into cloth tape or brake lining or braided in the same plant Weaving Weaving is done on looms in a similar manner to the method employed in weaving wool cotton or silk In the weaving of asbestos tape intended for electrical insulation single yarn with a very low cotton content is used Most tape looms are con- structed so that as many as twelve pieces may be woven at the same time It is the usual practice in weaving asbestos tape to wet the bobbins or cops with water before weaving The warp is kept dry Cloth is woven in much the same way as insulating tape Two- or three yarn is used Sometimes the yarn is reinforced with metallic wires generally brass or copper Either or both the warp and fill are dry or moistened with water depending on the use for which the cloth is intended Brake lining is woven on looms in the same manner as tape As many as eight pieces may be woven on one loom at the same time It may be woven dry or wet or with the warp impregnated with a dope solution This solution is generally a suspension of gilsonite in gasoline to which other ingredients may be added Final operations in the manufacture of woven textiles consist of calendering inspecting and winding of the products These operations are all mechanical ones and require no description Gasket Making of the important uses of asbestos cloth is in the manufacture of ring gaskets In this process the asbestos cloth is spread on the floor and impregnated with a solution of rubber in gasoline to which has been added barytes and other pigments The treated asbestos cloth is cut into strips of predetermined size and the gaskets formed by hand They are then coated with soapstone calendered and packed for shipment An inexpensive gasket and packing is made by twisting thick rovings into asbestos wick and rope Still other types of packings are made by braiding asbestos yarn on specially designed machines OTHER PROCESSES Other products containing asbestos are made in some of the plants included in this survey These products include asbestos paper insulation for steam pipes asbestos cements shingles lumber molded brake lining and cold molded asbestos articles generally electrical fittings and household appliances The fiber used for these purposes is of short staple The percentages of asbestos used in these ar- ticles is indicated in Table II Cooke and H found particles sixty microns in average particl length were me Methods of ] three general n particles One micrometer ins made by movin to determine th The second 55 to determ since been app dustrial dust- of the sample : by a stereopti images are mo readings With the slide and the micro projecti method is the more fully in Nature of A ricating plant three types fibers and cot . . . machine where two or into one thread For : the yarn may be re- ition is performed dur- rn is finally wound on other manufacturers or ning or braided in the similar manner to the silk In the weaving lation single yarn st tape looms are conmay be woven at the g asbestos tape to wet eaving The warp is Insulating tape Twoarn is reinforced with ther or both the warp ending on the use for manner as tape As om at the same time p impregnated with a uspension of gilsonite added en textiles consist of ducts These opera- Jescription - of asbestos cloth is process the asbestos ith a solution of rub- rytes and other pigut into strips of preand They are then 1 for shipment An isting thick rovings rovings of packings are made 1 machines PARTICLE SIZE DETERMINATION Cooke and Hill 22 in autopsies of asbestos workers have and found particles in the lungs measuring up to three hundred sixty microns in length Accordingly in the determination of the average particle size of asbestos dust all fibers irrespective of length were measured Methods of Particle Size Determination recent years three general methods have been used for measuring the size particles One method a direct one involves the use of the filar micrometer inserted in . microscope tube measurements being made by moving the micrometer adjustment and reading the vernier to determine the diameter of the particles introduced The second method an indirect one was introduced by Green 55 to determine the size of paint and rubber pigments It has since been applied to the measurement of the average size of in- dustrial dusts In this method an indirect one photomicrographs of the sample are made on lantern slides which are then projected by a stereoptican on a screen at a known magnification The images are measured and the average size calculated from these readings the third method the dust is collected on a microscope slide and the images projected on a ground screen with a projection apparatus and measurements made This latter method is the one used in the present study and will be described more fully in a later paragraph Nature of Asbestos Dust dust encountered in asbestos fabricating plants is uniform in nature It is seen to consist of three types particles more or less spherical in shape elongated fibers and cotton fibers Figure 1 is a photomicrograph of dust pro- in some of the plants e asbestos paper ingles lumber molded . generally electrical d for these purposes is used in these ar- FIGURE 1. PHOTOMICROGRAPH OF DUST FROM AN ASBESTOS FABRICATING PLANT MAGNIFICATION 600 DIAMETERS 9 duced when processing mill fiber noted The three types can be readily Because of the ticle size uniformity of this type of dust average par- the was other determined in two dimensons one at right angles to which Measurements were made of the longest diameters j were termed longitudinal diameters and a second set of tmeeramseudretmreanntsvserwseerediammaedteerast right angles to the first which were ! Method of Collection for the determination of ; size were collected by the use of the electric particle method yielded samples that precipitator 30 This ## projection and were satisfactory for direct micro- #4 measurement the sample were No intermediate steps for preparing @& necessary The precipitator employed was designed on the Cottrell precipitator The air was drawn principle of the & tube by a small rotary fan driven by a through the precipitating & the measured by a flowmeter motor The rate of rate of flow being . & 28.3 liters per minute The sampling was one cubic foot glass with an inside diameter porfecipitating tube was made of Pyrex # cover slip 22 by 70 mm in size 2.4 A number 1 microscope directly beneath the central was placed in the precipitating tube electrode The dust in the air was deposited electrically on this cover slip sample had been precipitated the cover When a representative mounted dry on a microscope slide glass was removed and A total collected at various of sixteen samples was of the workers operations all being taken in the breathing zone } Measurement projection apparatus with the arranged in a horizontal position was used microscope tives 8 mm and 2 mm and a 10x Apochromatic objec- employed This system practically elicmionmapteendsactoilonrg eyepiece were flat field furnished maximum light intensity fringes gave a and measurement of the long fibers permitted the The images were projected on a ground screen determined distance from the at a pre- in centimeter microscope This screen was ruled ] squares to facilitate measuring measuring A transparent rule was used and the size focusing of the projected images recorded in milli- meters Accurate focusing on each individual individual particle audrijnugstw meanst aocfcotmheplished by a remote control paatrttaicclheedbetfoortehemefaisn-e } microscope by a mechanical sleeve magnification disregarded } Predetermined magnifications of 2000 and 10,000 pending on the objective Measurements were used de- the method suggested by H. L. Green were made according to jective particles magnification 2000 the 56 Using the 8 mm oblongest diameters of two hundred particles were measured all lengths less than ten millimeters microns being neglected The number of millimeters fields examined five recorded An equal number of particles was was also 2 mm objective measured using the meters five microns and over w 1e0r,e000 and all particles fifty milli- ber of fields examined was Again the num- used to calculate the recorded These measurements were The method average of calculation is longitudinal diameter of the sample tion of the shown in Table III For the calcula- average transverse diameter the same procedure was 10 followed with measu longest diameters TABLETABLE 11 NAMPI ver Magnification _. min 11 ( ~~ ... 12 6.C 13 15 . 16 " 17 10.5 21 11.0 12 j 25 i - 2: ia 30 sy 17.5 oe 17.5 na cm 43 47 5 ue c 20 wt an 75 ha mo nh 101 110 120 1:30 340 160 170 17 20 53 me rr ma she 150 2400 230 240 919 330 370 4 a ......... 3150 : 1 16. 1830 Total a Partick Results the dust collected but no appreciable marked difference the two general g an be readily average par- ght angles to est diameters econd set of *, which were on of particle r 30 This direct micro- for preparing inciple of the precipitating of flow being me cubic foot ade of Pyrex 1 microscope ipitating tube the air was epresentative removed and samples was reathing zone he microscope omatic objec vepiece were inges gave a ermitted the en at a preen was ruled nsparent rule ded in milli- before measd to the fine cre used de- according to he 8 mm ohtwo hundred imeters five aned was also ed using the es fifty milli- ain the num- ements were f the sample the calculaocedure was followed with measurements being made at right angles to the longest diameters TABLE II EXAMPLE OF METHOD USED AVERAGE LONGITUDINAL IN THE THE DIAMETER CALCULATION DIAMETER OF Magnification 2000 105 Fields Magnification Magnification 10,000 112 Fields frxu 111211 10 12 13 14 15 VG 1358835 1358835 | 1358835 1358835 1358835 1358835 1358835 1358835 1358835 & ~fl ~ fl 5.0 6.0 6.5 7.0 7.3 8.0 sh 91.0 10.0 10.5 11.0 1.5 11.5 12.0 12.5 13.5 14.0 14.5 15.0 36.0 18.0 100 110 120 130 140 170 175 180 200 210 85.0 7.5 90.0 100.0 105.0 21 3 4 2 1 | s " 1 3 2 } 6 1 11 & 1 ! : : : ' 1 3 1 4 o 1 rs) 1 & 2 2 oe lisa ] 3 De 200 200 6.43M 3.48075 | 1.39230 | 0.64642 | 0.02521 | | 2.38350 0.26320 0.26320 0.28178 2.3M50 2.98850 | 5.22112 3 0.3 + 0.4 5 0.5 6 0.6 7 0.7 N 41.5 la 1.0 Ww 1.2 wns 1.8 1.8 13 1.3 201 2.0 23 Qn 23 2.5 Ty 8.0 an . the .0 i 4.5 Total * api 38 7. 2 w| 2 1 = VSTIO101 VSTIO101 VSTIO101 VSTIO101 VSTIO101 1 1 3.11 1.48 1.90 0.42 0.14 8.00 0.90 2.30 4.50 1.30 1.65 24.00 24.00 4.60 5.00 21 14.00 4. 4.50 20.0 101.C 101.C 0.61328 1.93970 1.29883 8.61800 6.6615 0.71272 2.23765 0.7903 3.31586 4.55-12 9 1.0442 5.356 tina Length image in millimeters millimeters 11 Length of particle in microns f Frequenley 112 f fi | Vann Oe | fx D Average Diameter Eifixum ee 2.65201 1.0570 1.9SDGE 8.61900 4.6410X41.6410X1 4.6410X1 7.9560 7.9560 2.81775 2.07950 2.00062 2.07950 1. microns Particle size determinations were made on samples of the dust collected at various stages in the process of manufacture but no appreciable variation was found However there was a marked difference in the average particle diameter of the dust from the two general grades of asbestos fiber The calculated longi- 11 MICRONS 0.1 0.2 0.6 0.8 0.3 Ls 3 0.1 0.2 0.3 0.4 0.6 = 45 r I TT 2 Va a |} A r. I 7. WA y 4 10 AA "4 a wT -- 30 PERCNTAGE 40 / 14a 50 Ee ia 50 a 60 at) 60 7I 70 | 95 95 98 98 99 99 99.9 FIGURE 2. SIZE FREQUENCY CURVES FOR DUST FROM . - DIAMETER ; - . LONGITUDINAL MILL FIBER HII TRANSVERSE DIAMETER CRUDE CRUDE FIBER AND TRANSVERSE DIAMETER MILL FIBER tudinal diameter of the microns while that of diameters were 0.69 n fiber respectively TL dred and two microns The percentage ire determined for longit shows these values paper The difference in t amination of Table \ ten microns or more dust occurred within + dust was 0.5 microns fiber dust fell within TABLE IN SIZE Size Group in Miereen 1.5-1.99 1.5-1.99 2.0-2.49 --.-- 2.5-2.99 2.5-2.99 oe. 3.0.3.49 3.5 3.9 4.0-4.4 4.5-4.99 5.0 and over Dusa All samples were Smith impinger 5 hol as the collectin the method describ were counted regar greatest diameter : the total The du in Table V. ete of the dust from crude fiber was found to be 2.12 tudinal diameter of mill fiber was 1.35 microns Transverse microns while that and 0.45 microns for crude and mill aes, diameters were 0.69Thmeicrloonngsest fiber observed measured four hun- fiber respectively oe dred and two microns of the various particles were onepre The percentage frequencies dimensions Figure 2 determined for longitudinal and tHra anzsevne'rsse logarithmic probability shows these values plotted on paper of dust is further shown by ex- The difference in the two types of the crude fiber dust was amination of Table IV Three per cent of the mill fiber ten microns or more in length while only 1.7 of the mill fiber dust occurred within these limits Twenty per cent of the crude dust was 0.5 microns or less in length while only 16 fiber dust fell within this range TABLE IV SIZE FREQUENCY DISTRIBUTION OF ASBESTOS DUST Size Group in Microns | i H Crude Fiber Mill Fiber ne = al _ Longitudinal Transverse =! Longitudinal Transverse Under 0.49 ..- 0.5-0.99 cee eee ee . . wee eeeee 87.7 87.7 27.1 30.1 % 26.0 7.8 46.9 Re M 7.5 78.3 20.3 _- 4.5-4.99 5.0 and over aes ...--- ee 4.0 1 3.0 Te DUST CONCENTRATIONS IN THE PLANTS collected colected by the modified form of the Greenburg- All samples were cent U. P. ethyl alco- Smith impinger 58 muesdinigumniDnuesttycoupnetrs were made according to All particles htohle amsetthheodcoldleescctriinbged in Part I of this report 41 microns in of size Particles less than ten were counted regardless ninety per cent of greatest diameter averaged afpoprrotxhiemadtifefleyrent operations are shown the total The dust counts in Table V. Jo TABLE TABLE YO suosopnid aENd | aqung Ocupation Jo Mixng Id Lowell Screnigs ONILVMEA SOLAUSV Insulating NL Brake lining lining SNOLVUAID Cloth dry | uo Crude Spoling * JO beams ep JOQhT AMVs eb) ring OA j-1uedQ ATE inch [osu] 209yLT OIVTgSAIGN Bulpoag10d CONETRAIONS The relative dey Vee the four asbestos fala VI. This suminar \ (t plants has been prepa TANLE MI Ria vias 2 : UcYin WW a "yO JoM dOM WwndleK~ditn fopesd sued Alp (HUUE(HG : . 44 S1pdsewjoCsewlBdsB Tores : (UW (UY " I opndy-uj Std-sju3yp(d-:ONIBurplfy{d-o1QFulp S4pyXap)Jom) ) vu) 1.0 fap) Aap) Yow) stuReq so" a o> Sip dieap digm suUvdupvLdET, sp, UIRL URL ued 0.5 Uses vf BajyoedSupydn SupaAUEAULUILSap)Lip) Juqy Mies diva Buty Sjoysu Gy sog y UO poe TulpfrsuFpRnsuyHSeuErNjseugLnsoau4aeUsyevtaeONBIgEqiotyqyop.ysot (iLieC-- your qoup youy daun aor Supls % - aU SuavesufaeoFrupaeve.aufaweAgROe ZuPrABya supa Augar aA Fug. suysdgFU ! Supuy Jujuog Sups98g sujpyeagsuypesySurpyws oy > dsy ss it NAG pun mlogy 14 Tie qead tired 1 Preparation ane Car ius Weaving stall Mul Speen Twisting. Gasket, Waning. ale, Reape Tt will be seen ue preparing room, wir men t The lowest + ring gaskets. Vhe relative dustiness. d partinent. The cote ot the process \ awnde method of manutiact necessary to diseus- eral operations. Th SESS 5uzvevw wt ye s - 2- Go= = 2 a = =Fa me,ere Pay me-r TE 5 7a =r @&-e WEE ZicoF =e en BRAD elie. Cette taLAU ousave wer _SS ez ane eo we a e~reuv BQre eats oSss y sg eta a) Um ESTEmeeSw~~ D wm > Ze a =z FDv"E r TH Lyr = B-LSTeCzfs SEHeme SE teb AOoDeysVesevwau F~~ E$4 =& a'-5xA rectet : fiber after it had Ix posed to a concent: In the mining the degree at chust the type of fiber u- 10.6 when a mixtiy mixing picker. Th bams bams . tubing warp packing on inch inch warp 1 ~fl Braiding Windg Braidng | Spooling Wick Spooling WindgJURISTW Warping Braidng of dustiness in the various departments of The relative degree surveyed is indicated in Table the four asbestos fabricating plants surveyed VI This summary of the average concentrations from the different plants has been prepared from the data contained in Table V. TABLE VI RELATIVE DUST CONCENTRATIONS IN DEPARTMENTS OF ASBESTOS PLANTS Department Number of Samples Concentration Millions of Particles per Cubic Foot of Air wee Minimum i Maximum , Average 316 Preparation and Carding ..----.------2-00- crete - - 41 Weaving and Mule Spinning ....---------. 2 0.6 123.3 | | 44.26 aoe eH 1.9 74.2 16.87 Twisting Winding Rope and Wick Braiding wees nad 0.3 20.6 4.64 _-- It will be seen that the highest dust concentration occurs in the where the asbestos receives its preliminary treat- pmreenpt arinTgherolo om west concentration is associated with the making of ring gaskets The figures given in Table VI while showing the relative dustiness do not explain fully the conditions in each de- The concentration of the dust in the successive phases partment of the varies depending on the type of fiber used and the process these variations it is method of manufacture In order to explain necessary to discuss separately conditions encountered in the sev- eral operations The figures given in the following paragraphs repmillions of particles per cubic resent the concentration of dust in foot of air Preparation dust in the preparing rooms is practically all due to pure asbestos no cotton having yet been added The de- of dustiness depends primarily on the type of fiber used Thus gree it was found in plant B that when mill fiber was fed into the Saco- Lowell opener the average count was 119.4 as compared to a con- centration of 33.2 when the longer crude fiber was treated in exactly the same way In plant D one of the operations involved the screening of short- length mil fiber without first passing it through a Lowell opener The employe engaged in feeding the material onto the screen was found to be exposed to a concentration of 65.7 A sec- ond workman whose duty was to fill burlap bags with the screened fiber after it had been removed from the shaker by ; suction was ex- posed to a concentration of 96.1 In the mixing room where the cotton and asbestos are blended the degree of dustiness was again found to depend primarily on the type of fiber used For example the concentration of dust was 10.6 when a mixture of cotton and mill fiber was being fed into the mixing picker The concentration dropped to 3.1 when the mixture 15 was made from crude No. 1 fiber In plant D when the lowest grade mix was fed into the picker the concentration was 84.7 Carding marked difference in the total dust count in the carding operation as the result of using different grades of asbestos will again be seen When the crude fiber mixture is being carded for the manufacture of electrical insulating tape a concentration of 1.1 was noted The mixture for cheaper grades of yarn such as that used for weaving brake lining is generally made from mill fiber The concentrations of the dust when mill fiber was being carded were 23.4 24.3 29.8 and 80.0 The samples were collected in card rooms of various plants Occasionally the loose web of asbestos and cotton as it emerges from the breaker card and passes over the camel becomes broken It is then the duty of the operator to go to the rear of the card and repair the broken web the task requiring approximately half hour per day It was found in one plant that the employee was exposed to a concentration of 57.5 during this time while during the remainder of the day he was exposed to a con- centration of 24.3 At intervals it is necessary to shut down the card and clean or strip the rolls This is done by scraping them with a hand which is a brush covered with strips of card cloth The cylinders are slowly turned by hand at the same time The dust concentration during this operation was 5.5 Sometimes the rolls are cleaned while they are being turned at the customary carding speed The employes stated that this was a very dusty operation but it was impossible to obtain samples during this procedure Weaving concentration of dust in weaving is dependent on many factors but principally upon the following 1 quality of the warp and fill being used 2 whether weaving is done dry or wet 3 conditions of ventilation and 4 nature of the finished product The influence of the first factor is shown in the weaving of insulating tape and brake lining in plant C. A concentration of 6.9 was associated with the weaving of tape made from crude fiber In the weaving of brake lining made from mill fiber the count was 27.1 In both of these operations the warp was dry and the fill wet As pointed out in the description of the weaving process page 8 weaving may be done either with the yarn dry or moistened with water The presence of moisture materially decreases the concentration of the dust For example in the wet weaving of brake lining the concentration is 6.1 but when it is woven dry the count increases to 27.0 The effect of ventilation is shown in the weaving of cloth in plant 1. In this plant ordinary electric fans were located just back of the weavers so that dust generated in the process would be blown away from the worker's breathing zone When the fans were operating the concentration of dust in dry weaving of cloth forty inches wide was 9.9 rose to 33.3 When the fans were turned off the figure The fourth factor nature of the finished product also influences the degree of dustiness Thus the average concentration en- 16 countered in weavin and of brake lining The looms in tim moved periodically periodically with a flexible rubb the time requiredoperati During this operati Spinning ci depends on the typ yarn A count of from crude fiber for from a high grade ,, dust associated wit cheapest gade ma the mule spinning i to which the mule all operations from same room Const centration is due t Other Operation the production of tions of dust asso plant A this was ascribed to windi performed in the figure of 2.4 was i figure increased to Warping is a spools or warp b dust the concenti Dust In addition to plants manufactu was considerably products include asbestos cement bestos paper whi fiber Determin some of these This survey w tos dust but ot hazards were o gasket and mole room and lead the finishing as are lacquer solv erations In the lowest grade as 84.7 dust count in the grades of asbestos re is being carded a concentration of s of yarn such as y made from mill li fiber was being les were collected tton as it emerges back becomes go to the rear of requiring approxione plant that the 5 during this time exposed to a con- card and clean or with a hand th The cylinders The dust concentrahe rolls are cleaned arding speed The ration but it was ure ng is dependent on 1 quality of the s done dry or wet he finished product the weaving of in- oncentration of 6.9 - from crude fiber iber the count was Ary and the fill wet g process page 8 of moistened with decreases the con- t weaving of brake oven dry the count ing of cloth in plant ocated just back of ess would be blown hen the fans were aving of cloth forty rned off the figure luct also influences concentration en- countered in weaving insulating tape was was 10.5 that of cloth 21.3 and of brake lining 23.0 The looms in time accumulate a great deal of lint This moved periodically generally once a week by beating the with a flexible rubber paddle Each weaver cleans his own the time required being approximately half hour per During this operation the dust concentration was 74.1 is reloom loom week concentration of dust in the mule spinning room Spinning of asbestos fiber used in the making of the depends on the type 2.1 existed during the spinning of yarn made yarn A count of A made from crude fiber for the weaving of insulating tape yarn of 5.5 The from a high grade of mill fiber produced a concentration the dust associated with the spinning of commercial grade yarn cheapest grade made was found to be 13.2 These figures are for the mule spinning in plant B. In plant A the average concentration which the mule spinners were exposed was 23.0 In this plant talol operations from preparinigt itso iwmepoasvsiinbgle wteorestcaaterritehdat otnhisin cotnh- e same room Consequently centration is due to mule spinning alone minor mechanical operations necessary in Other Operations textiles have relatively small concentra- the production of asbestos tions of dust associated with them In the winding operation in this number cannot all be plant A this was found to be 8.0 Again were ascribed to winding because of the fact that all operations in the same room In plant B. in the twisting room a performed found associated with twisting two yarn This figure of 2.4 was 4.0 when yarn was twisted three figure increased to is a mechanical transfer of the twisted yarn to large Warping beams for the looms It gives rise to very little spools or warp dust the concentration being 1.0 DUST CONCENTRATIONS IN OTHER PROCESSES In addition to the fabrication of asbestos textiles one of the manufactured other products in which the amount of asbestos plants less than the amount used in textiles These was considerably included 85 magnesia insulation molded brake lining products lumber and tile One plant made as- asbestos cemewnhtischshcionntgalienss ninety per cent of staple mill bfeisbetros pDaepteerrminations of the dust concentrations were made at shown in Table VII some of these operations The results are OTHER POTENTIAL HAZARDS This survey was concerned only with the hazard caused by asbestos dust but other materials that must be considaenreddbeanszoploteinnttihael hazards were found These materials are gasoline and molded brake lining departments tale dust in the gasket graoso kemt and lead compounds in the rubber mixing department In the finishing asbestos lumber and tile additional potential hazards are lacquer solvents and sand from the grinding and polishing op- erations 17 TABLE VII DUST CONCENTRATIONS OF MISCELLANEOUS ASBESTOS PLANT Department Operation Paper Mill Shingle plant Magnesin 15 asbestos Clutch Facing Crushing asbestos mill fiber 22.2.2... Bagging asbestos mill fiber 2. Sawing air cell pipe covering 022. Sawing asbestos lumber _. Sanding asbestos bumber and tile Grooving bathroom the oo... Dusting tile paint spray booth - veeeee Filling barrels with magnesia . Shoveling mnguesin on pile Dumping barrels into mixer oo... oo. Cleaning pipe molds ool... eee. ee. Feeding insulation into trimmer .... Removing insulation from trimmer Crushing and bugging scrap ooo. . Skinning asbetos facings Grinding asbestos paper clutch facings an a. Drilling paper clutch facings Number of Samples . Coneentration in Millions of particles per cuble foot of Air 253.253.00-26-5.0 22563.05-2.650.0 3.9 404.4404.4 312.7 12.2 ASBESTOSIS Encountered in Ash 0 Complete physical es 48 men to women 1 Part II of this report were used as exposure stricted to those emple longest employed wer a sufficient number ane paid to the group wit particular operation VIII shows their age TABLE VIII s | 4 Gromp Controls Asbestosis Negative Total Asbestosis was de or 25 per cent of tu as negative and the one individual had p been the primary 6 eliminated from any bestosis were divide monary fibrosis no ae mation of the degre extent of fibrosis ... ings Ol past me The present past eh:cca histories were secur might influence the av symptoms were a dominating subject ONCE and dyspnea Ot and frequent cold-cold- Role symptoms Fn Samples Concentration in Millions of particles per cubic foot of Air 53.3-154.2 53.3-154.2 130.4 38.4 130.2 19.6-22.3 ASBESTOSIS The Effects of Exposure to Dust Encountered in Asbestos Fabricating Plants on the Health , of a Group of Workers Complete physical examinations were made of sixty persons 48 men 16 women employed at the time in the plants listed in Part of this report Of this number seven men without previous exposure were used as controls Selection of the workers was re- stricted to those employed it textile manufacture Those workers longest employed were chosen because the necessity of including a sufficient number from this group is evident Attention was also paid to the group with exposures particular operation at which the of shorter duration and worker was employed to the Table VIII shows their age distribution TABLE VIII DISTRIBUTION BY AGE OF ALL PERSONS EXAMINED . Group Number of Persons Examined Under 300 Number in Age Group mu JC - : 50 ! 160 and over Controls eevee ee ce tees 7 1 2 Asbestosis 00 ....2. 200. eee 14 . 7 th _. 1 Negative 0. eee eee : 17 Ve iF n 2 Totals ee ee or} 16 :: 17 4 Gi 2 2. oe ae eee eee Asbestosis was found in fourteen persons 12 men 2 women or 25 per cent of the exposed group Forty persons were diagnosed as negative and the remaining three doubiiul Of the latter group one individual had previous exposure to silica dust which may have been the primary or contributing cause and as a result has been eliminated from any further consideration The cases having aso bestosis were divided into those having slight and moderate pulmonary fibrosis no advanced cases having been found The esti mation of the degree of involvment depended on the amount and extent of fibrosis seen roentgenologically and in the clinical find- ings The present past and family medical and previous occupational histories were secured from each worker Direct questions which might influence the individual's replies in regard to his subjective symptoms were avoided in obtaining chief complaints The predominating subjective symptoms in the positive group were cough and dyspnea Other major subjective symptoms were dry throat and frequent colds One individual in this group had no subjective symptoms 19 Objectively the major symptoms were again cough and dyspnea Thirteen persons of those diagnosed positive for asbestosis plained of cough and eight of dyspnea com- Other frequently elicited objective symptoms were frequent colds palpatation weakness precordial pain and pharyngeal dryness No objective symptoms could be obtained from one individual in the positive group Occurrence of acute respiratory infections was particularly observed in the past medical history Frequent coryza or other upper passage infections which did not result in loss of time of three or more working days were listed as objective symptoms Pneumonia during the course of employment occurred in three of the positive and seven of the negative group The past medical his- tories were otherwise negative except for an attack of pleurisy in one individual of the exposed group diagnosed as negative Family histories and in particular tuberculous contacts were noted Two workers with asbestosis had roentgenological evidence of healed tuberculosis and negative family histories Two others who showed evidence of healed tuberculosis and who did not have asbestosis also had negative family histories Physical examinations were made with the workers stripped to the waist Mean variations in the present and greatest weight were less in the asbestosis group than in the group diagnosed as nega tive and in the controls minute oral temperatures showed a maximum elevation of 0.5 Four persons having asbestosis had an elevation of temperature and eleven in the negative group showed it Elevation of body temperature in the control group was absent The mucous membranes of the nose and throat of the entire group were essentially negative The conjunctivae did not appear to be irritated Tenderness over the antra and frontal sinuses was not found Deflected nasal septa were common and diseased tonsils were noted in a few cases The external show evidence of plugging or irritation auditory canals did not Clinical examination of the thorax included inspection palpation percussion and auscultation of the heart and lungs A tendency to increased posterior diameters of the chest in the positive exposed group was noted In the positive group the respiratory murmur and vocal resonance were impaired in five cases Crepitant subcrepitant sibilant and sonorous rales occurred in nine of the asbestosis cases the two latter types being predominant The recognition of cyanosis presented a difficult problem When it occurred the skin had an unhealthy leaden hue with variations in the degree of intensity in the three individuals in the positive group showing this physical sign Roentgenological examinations made of all workers included fluoroscopic examination stereoscopic anterior posterior and oblique skiagrams of the chest In addition to noting gross chest pathology the movement of the diaphragm was measured in centimeters dur- ing the fluoroscopic examination Right and left oblique exposures of the chest aided in the interpretation of the films and in the detection of thickened pleura particularly The hila trunk and markings of the fibrotic lungs were increased in prominence lunIng some films the lung fields showed a slight tendency toward beading and nodulation A small area in the distal third of the lung in one 20 film suggested atelec emphysema occurre hesions were noted i domes of the diaphr of the negative expe and two of the neg evidence of healed disease in four of the The occurrence of losis were determite each person Each obtaining the sputur morning sample each sample After was centrifuged for and the supernatant the solid centrifuge three minutes A scope slide and exa both 8 mm and r FIGU ASBE The greater per color but a few v pale yellowisbrhe The largest asbes The bodies occu present singly or or a dumb s strand at a positio micrograph of a of two or three as a x x 2 cough and dyspnea for asbestosis com- er frequently elicited alpatation weakness objective symptoms positive group was particularly ob- oryza or other upper loss of time of three e symptoms Pneurred in three of the he past medical his- attack of pleurisy in as negative ilous contacts were genological evidence stories Two others id who did not have workers stripped to greatest weight were diagnosed as negamperatures showed aving asbestosis had gative group showed I group was absent of the entire group id not appear to be tal sinuses was not and diseased tonsils tory canals did not nspection palpation ngs A tendency to hest in the positive oup the respiratory - cases Crepitant rred in nine of the Jominant ult problem When que with variations uals in the positive workers included sterior and oblique oss chest pathology in centimeters dur- oblique exposures ms and particularly a trunk and lung in prominence In ney toward beading Lof the lung in one atelectasis Increased aeration such as one sees in emphysema film sugested atelectasis atelectasis a few cases Thickened pleura anofd ad- hesions were noted in a few cases The average movement that that domes of the diaphragm of the positive was group less positive positive negative negative the and two of the negative evidence or group were found with roentgenological tuberculosis tuberculosis FurtherFurther eevvidenice dence of pulmonary pulmonarpuylmonary disease four the positive group was clubbing of the fingers sputpurmopoefrBm.cetohtlouldbeecrtcu- instructed the The occurrence of asbestos bodies and the presence losis were determined in a single specimen of obtained in method of each person Each emplove was obtaining the sputum specimen and was requested a to added to morning sample An equal volume of antiformin was mixture each sample After complete digestion of the mucus the mixture 2000 was added approximately centrifuged for three minutes at Distilled to and the supernatant liquid decanted recentrifuged recentrifuged the solid centrifuged portion and the water mixture transferred three minutes A drop of the deposit was transferred bodies under scope slide and examined for the presence of asbestos recentrifuged for to micro- bodies under both 8 mm and 4 mm objectives FIGURE 3 PHOTOMICROGRAPH ASBESTOS BODY MAGNIFICATION DIAMETERS OF 600 whitish The greater percentage of sputum specimens were of a asbestos color but a few were purulent The bodies were a number pale yellowish brown color and varied in size shape and number length The largest asbestos body found measured 117 microns in length The bodies occurred singly clumped and as fragments When narrow present singly or in clumps they presented a bead appearance or a dumb shape with bulbous ends tapering into a strand at a position midway between the ends Figure 3 is a photo- average micrograph of a single asbestos body In one specimen an of two or three asbestos bodies or fragments of bodies were seen in 21 cach power field while in others only one or two bodies were found in the entire specimen Table IX gives the occurrence of asbestos bodies in a single specimen from each person Merewether 74 reports that the presence of asbestos bodies cannot be taken at present as indicating anything more than previous exposure to asbestos dust This is in accord with our findings for it will be noted that they were found in specimen obtained from one of the controls who at the time was suffering from an acute bronchitis productive of a purulent sputum This worker had been em- fifty ployed as a packer foreman in the magnesia department for years His only exposure to asbestos dust was a rare visit to other parts of the plant TABLE IN OCCURRENCE OCCURRENCE OF ASBESTOS BODIES IN SPUTUM Group Number Percentage Based on Total Number of Persons Based on Specimens Examined Examined Asbes Tosis 0 Nega GAP Cong fro Ashes toss Nega- tive Control Ashes Losis I Nega tive Con trol Asbestos Bodies present i 101 1 1 50,500,0 23.5 34.3 55.3 47.6 23.0 Asbestos Bodies absent Qh 11 No Specimens # 35.7 i 26.2 42.5 41.6 h 11.3 50.0 12 a Ta Totals oo. 2. 12 7 A single sputum specimen obtained from each individual was stained and examined for the presence of B. tuberculosis Both direct smears and centrifuged antiforminized specimens were found to be negative Clinical examination of the heart showed the apical impulse to be displaced in few cases Apical systolic murmurs were heard in five of the positive and two of the negative groups The blood pressure was determined with a standard mercury sphygmonano- meter Hypertension although present in a few cases in each group occurred only the older workers Roentgenological evidence of enlargement of the heart was not found However the cardiac silhouette in two to be top normal in size individuais having asbestosis was found Electrocardiograms of fifty of the workers were made following a minute rest period during which the subject was in a reclining position while eight were taken with the subject in a sitting position following a short rest period The most consistently positive cardiographic finding in the entire group was low voltage It was found to be present in seven of the positive and 20 eighteen of the m trols Right predi control group bui asbestosis and dre most frequently i vanced age groups of individuals with have changes in i the exposed grost plex two of these pared with an at R interval wa sons found to be A functional to formed by having body twenty five termined immedi end of a two mined immediatel Table N gives ilu were seen in the posed group pulse rate resting rate as Indi two TABLE CONTROLS Marle NEGATIVE Mabe Pemeri ASBESTOSTS Male Female tt . 1 Pulse rate rate * Respiratory rate Asbestos wat which has bece and overgrowth growths are li the feet Fort these papillom or two bodies were the occurrence of rson Merewether cannot be taken evious exposure to ings for it will be ed from one of the acute bronchitis rker had been empartment for fifty rare visit to other IN SPUTUM entra Based on Specimens Examined Vstes .- Nega Tix | Con- trol . 47.6 25.0 1 " 75.0 individual was rculosis Both mens were found pical impulse to were heard in The blood A sphygmonano- cases in each genological evi- However the Josis was found made followubject was in a subject in a sitost consistently group was low he positive and eighteen of the negative groups compared with four of the controls Right predominance was not present in the tracings of the control group but did occur in two tracings of individuals with asbestosis and three of the negative group Left predominance was most frequently found in the tracings of individuals in the ad- vanced age groups Katz and Slater 62 found eighty per cent of individuals with a second positive wave of the R complex to have changes in the heart muscle Our findings show that six of the exposed group had a second positive wave of the R complex two of these had asbestosis and four were negative as compared with an absence of this finding in the control group The R interval was increased in the tracings of two exposed per- sons found to be negative A functional test of the individual's response to effort was per- formed by having him place one foot on a chair and then raise his body twenty times in thirty seconds The pulse rate was determined immediately before and after exercise and again at the end of a minute rest period The respiratory rate was deter- mined immediately before and two minutes after the exercise test Table X gives the results of the functional test Greater variations were seen in the rate of respiration following exercise in the ex- posed group pulse rate resting rate as compared with Individuals with a two minutes after the controls than were seen in the pulse rate of 10 above the normal exercise were considered abnormal TABLE X. FUNCTIONAL TEST OF RESPONSE TO EP PORT Group Number Percentag 2 Resporation we eee Number Percentage CONTROLS Female NEGATIVE Mule : vere ee : a Female 02. 0 ee ee ee cee ee eee ee 153 " 61.3 ASBESTOSIS Maie 1 a Female wee eee tee eee ee - Son - . 66.6 t 50.0 Pulse rate 10 above normal resting rate two minutes after #Respiratory #Respiratory rate 2 uhove normal resting rate two minutes exercise after exercise Asbestos warts are thought to be produced by a fiber of asbestos which has become lodged in the skin largely through the irritation and overgrowth of the horny and malpighian strata 27 These growths are usually found on the hands but may also develop on the feet Forty per cent of the exposed group had one or more of these papillomas on their hands 23 Routine blood counts and urinalyses were made on each individual examined Haemoglobin was determined by the Haden and Hausser colorimetric method and expressed as grams of haemoglobin per 100 cc of blood Smears for differential counts were stained with Wright's stain and 200 cells studied microscopically using a 2 mm oil immersion objective Practically no change was observed in the blood picture of the three groups Comparable average variations did not occur in either the erythrocyte or leucocyte count In two individuals with moderately advanced pul- monary fibrosis the total leucocyte counts were 10,800 and 11,400 with corresponding increases in the percentages of polymorpho polymorpho nuclear leucocytes Changes in the percentages of other types of white cells were not observed Urine specimens were collected from each worker at the time of physical examination Specific gravity albumin content and the presence of sugar were determined and a microscopic examination made of a centrifuged portion Urinalyses were essentially negative except for a trace of albumin in four of the positive and thirteen of the negative exposed groups as compared with two of the controls A brief summary of the clinical findings of three asbestos mill workers and the accompanying illustrations Figures 4 to 7 inc are presented to show the two stages of asbestosis encountered in this study Case number White male aged 30 years Chief complaints Objective symptoms- Occasional frontal headache 2 Epistaxis rare 3 Dry unproductive cough 4 Coughing attacks precipitated by strenuous exer- cise Past Medical History childhood diseases Traumatic orchitis 1934 Occupational History working at Mule spinner worsted mill 2 years bestos fabricating plant 9 years 16 years Ice man of age 1 year Milkman 2 years Mule spinner as- Physical Examination Apparentlyhealthy adult male Height 62 inches Weight 122 pounds greatest weight 122 pounds Skin clear No cyanosis Asbestos warts on both hands Pulse rate before immediately after and two minutes after exercise 84 100 72. Respiration rate immediately before and two minutes after exercise 20 22. Chest normal shape percussion normal breath and voice sounds normal sibilant and sonorous rales both bases Heart apical impulse 5th interspace clavicular line no murmurs Blood pressure 134/90 Diaphragmatic movement right dome 2.5 cm left dome 1.5 cm Thoracic cage is negative The trachea is in the midline The cardiac silhouette is within normal limits of size The arch of the aorta is not widened The domes of the diaphragm are somewhat irregular on the left side but fairly irregular on the right The pleura appears to be slightly thickened on the left side and is more clearly shown in the oblique view In the right apex there is possibly an old healed tuberculous process giving the appearance of an apical cap The hila are increased in prominence The trunk markings and linear markings are increased in prominence 24 made on each individ- 1 by the Haden and as grams of haemoerential counts were died microscopically ically no change was groups Comparable erythrocyte or leucoately advanced pulre 10,800 and 11,400 ges of polymorpho- es of other types of orker at the time of in content and the oscopic examination essentially negative itive and thirteen of two the controls three asbestos mill Figures 4 to 7 inc dosis encountered in Epistaxis rare 3 Dry tated by strenuous exer- ammatic orchitis 1934 var. car Milkman 2 years Mule spinner as- ale Height 02 inches Skin clear No cyanosis . munediatelmunyediately after and 09 rate immediately beest normal shape per- sibilant and sonorous pace clavicular line; 1. left dome 1.5 cm he midline The cardiac rch of the aorta is not hat irregular on the left appears to be slightly wn the oblique view berculous process giving ncreased in prominence reased in prominence FIGURE 5. CASE NUMBER 447 Electrocardiogram rate 72. R interval 0.16 second Voltage 4 mm Asbestosis slight Case Number White male aged 47 years Chief Complaints1- Cough 2 Shortness of breath Past Medical History Usual childhood diseases Gonorrhea 1922 Ocempational 2 years History Laborer Farmer until 29 years of age grana mill 1 year Preparation Laborer steel works room asbestos mill 15 years functional exercise utes after function Fluoroscopy Ray thoracic cardiac silhouette are regular The The lung markm Electrocardiogram ( mm Low voltag Diagnosis TABLE XI INCIDEN INCIDEN OCCUPATION I Occupintiol Menage Comet tration Melos 01 Pak citys feet Preparers and 11 Carders Wenvers at~-l . Spinners FIGURE 7 ELECTROCARDIOGRAPHIC TRACING OF CASE NUMBER 447 Physical Examination General appearance fair Skin clear Height 59 inches Weight 120 pounds greatest weight 125 pounds No clubbing of fingers No asbestos warts Nail beds not cyanotic Chest normal shape per- cussion normal respiratory murmu within normal limits vocal resonance unaltered sibilant and sonorous no murmurs Pulse rate before rales Heart no immediately after apparent and two enlargement; minutes after 26 Winders Twisters Warpers etc. Totals The principal degree of the the dust length  second Voltage 4 mm nh morrhea 1922 v. Laborer steel works a room asbestos mill 15 ACING OF CASE ACING OF CASE Icar Height 59 inches No clubbing of fingers dest normal shape peral limits vocal resonance en apparent enlargement 1. and two minutes after functional exercise test 76 118 76. Respiration rate before and two minutes after functional exercise test 14 18. Blood pressure 134/90 Diaphragmatic excursion; right dome 1.7 cm left dome 2.5 cm Ray thoracic cage is negative The trachea is in the mid The cardiac silhouette is within normal limits The domes of the diaphragm are regular The hila and trunk markings are increased in prominence The lung markings are also increased in prominence Electrocardiogram rate 60. mm Low voltage of all Q R interval complexes 0.16 second Voltage 3.5 Diagnosis moderate TABLE XI INCIDENCE AND DEGREE OF ASBESTOSIS WITH RELATION OCCUPATION DUST CONCENTRATION AND YEARS OF EXPOSURE TO Occupation Preparers Carders . Average | Concen- : | | tration Millions l of particles per cubic Years of fool Exposure i Total Number Examined Negative Asbestosis sone is Slight Moderate Advanced Doubt ful 0-5 . " 1 oe -- -- 44.26 a r 11 10 o a 10-20 10-20 2 Over Y Total 14 oO i} 1 5 ~ ~ | ZT - - Co an -_ , ~ 2 G o. 1 Weavers 217101 Spinners * 0-5 . 6-10 a - 16.87 1 15 1 3 16:20 ny over on Total Vs | 11 -- 1 n 1 -ae -- : 7 . ae Winders Twisters Warpers etc. IL 6 , vi . 4.04 11-15 " 20 1 f " 1 I i . Total 24 , 21 1 ! : 2 ~ . 1 - -- oe : 7 , 1 Totals i " 40 7 7 2 . The principal factors now thought to determine incidence and degree of the pneumonoconioses are nature and concentration of the dust length of exposure and individual susceptibility The in- 27 cidence of asbestosis with relation to occupation concentration of the dust and length of exposure in the fifty persons examined in this study is indicated in Table XI Obviously the examination of such a relatively small group prevents the formation of definite con- clusions as to the influence of these factors Nor is it possible from our findings to establish the maximum safe concentration of asbes- tos dust in the air the necessity of a However the results of this investigation show reduction of the dust concentrations in those operations shown in Part II of this study where there is continuous exposure to high concentrations SUMMARY 1 The concentration of dust in asbestos fabricating plants depends primarily on the grade of asbestos mill fiber gives rise to higher concentration than crude fiber Operations arranged in decreasing concentration of dust are preparing carding weaving spin- ning twisting winding and warping 2 The average particle size of asbestos dust is stated in two diameters longitudinal and transverse 3 Petrographic analyses of dust encountered in asbestos fabricating plants collected in the workers breathing zone shows it to contain no free silica 4 Fourteen or 25 of fifty workers employed in the textile departments of asbestos fabricating plants in Pennsylvania had both clinical and roentgenological evidence of asbestosis ACKNOWLEDGMENTS The Department of Labor and Industry of the Commonwealth of Pennsylvania wishes to thank the management and employes of the plants studied for their cooperation and interest which made the success of this study possible Dr. H. K. Pancoast and Dr. E. P. Pendergrass of the University of Pennsylvania whose interpreta- tions of the films have been used Dr. G. W. Grier of the of Pittsburgh for his interpretation assistance and adviUcneiveinrsitthye roentgenological study Dr. J. Evans Schechle Secretary of the Pennsylvania Department of Welfare in extending to the Department of Labor and Industry the facilities of his department Dr. C. A. Laubach roentgenologist and cardiologist of the Norristown State Hospital for doing a large majority of the ray work and his technicians for the routine laboratory examinations Dr. D. Heard and Dr. A. B. Fuller of the University of Pittsburgh and Dr. C. Wolferth of the Univer aty of Pennsylvania for their assistance and interpretation of the cardiograms BIBLIOGRAPHY 1. Amiante Hyg du trav 191-192 1930 2. Anderson H. V. and Clark G. .: Application of rays in the Classification of Fibrous Silicate Minerals Termed Asbestos Ind and Eng Chem 21 Commonly 924-933 192 28 3. Auribault dans les trav p 4. Baader E. med We 5. Beger P Arch 21 6 Beger P. 1 5.3 5.3 7. Beger P. J. Ind 1 8. Deintker behy 9. Beintker 1931 ! 10. Bowles O U. 11. Bridge J. of Fact don 19 12. BromleyD -A Asbesto Radio 1934 13. Buttnerasbest muss 14 Cirkel In tion N Dep't 15. Clynes 16. Cooke " Asbest 17 Cooke V 18 Cooke V 1928 19. Cooke 1 Pulm Abstr Hyg 20. Cooke I Lungs 1931 oncentration of ns examined in examination of of definite con- t possible from ation of asbes- stigation show tions in those is continuous ting plants de- gives rise to a rranged in deweaving spin- stated in two asbestos fabrie shows it to 3 Auribault Notes sur l'hygi^ne et la s^'curit^'des ouvriers dans les filatures et tissages d'amiante Bull de l'Insp du trav p 120-132 1906 4. Baader E. W Asbestose mit Warzenbildung med Wchnschr 79:83 79:83 1932 M^...nchen 5 Beger P. .: Ueber die Asbestosis K^rperchen Virch Arch 290 280-353 1933 6. Beger P. .: More on Asbestosis Bodies Virch Arch 293 530-539 1934. Abstr J. Ind Hyg 17:32 1935 7. Beger P. .: Injurious Factors in Asbestosis and Silicosis Med Klin Sept. 14 1934 p 1258-1261 1922-1927 Abstr J. Ind Hyg 17:32 1935 8. Beintker .: Asbestosis Arch f Gewerbepath u Gewer- behyg 345-358 1931 9. Beintker .: Asbestosis Bodies Virch Arch 293 527-529 1934. Abstr J. Ind Hyg 17:33 1935 10 Bowles Oliver Domestic and Foreign Deposits U. S. Bur Mines Inf Circ No. 6790 June 1934 11. Bridge J. .: Asbestosis In Ann Rep of the Chief Insp of Fact for the Year 1928 p 95. 11. M. Stat Off Lon- ed in the tex insylvania had i don 1929 12. Bromley J. F. Wood W. B. Ellman .: Pneumonoconiosis -A Discussion Part Silicosis Part Pulmonary Asbestosis Part Pulmonary Asbestosis Brit I. Radiol p 262-295 1934. Abstr J. Ind Hyg 1023 monwealth of i employes of t which made and Dr. E. P. interpreta- the University advice in the 1934 13. Buttner W. and Trillitzsch .: Die Bergflachslunge asbestosis und was der deutsche Artz von ihr wissen muss Tuberkulose 11-14 1931 14. Cirkel Fritz Chrysotile Asbestos Its Occurrence Exploita tion Milling and Uses Mines Branch Bull 69. Canada Dep't of Mines 1910 retary of the the Depart- partment Dr. ae Norristown 15 Clynes Asbestosis and Silicosis Brit Med J. 379 1931 16 Cooke W. .: Fibrosis of the Lungs due to Inhalation of Asbestos Dust Brit Med J. 147 1924 may work and 17 Cooke W. .: Asbestosis Brit Med .. 1024-1025 1927 amts tsbDurr.ghJ. anDd. 18 Cooke W. .: Pulmonary Asbestosis Brit Med J. 585 Sevee . for their as- 1928 Se 19 Cooke W. .: Asbestos Dust and Curious Bodies Found in Pulmonary Asbestosis Brit Med .. 578-580 1929 Abstr J. Am Med Assn 95 1431 1930. Abstr J. Ind ee Hyg 12:34 1930 Oe of rays in 20. Cooke W. .: Asbestos Dust and Asbestosis Bodies from tT ee Is Commonly Lungs of Asbestos Workers J. State Med 544-548 924-933 1929 1931 29 - NES a RUM niin ct OL eee aa ated ok hte NO atte. VN 2 ay Cooke W. .: Anthracosis Presenting Curious Bodies Similar to Those in Asbestosis Brit Med J. 656-657 1932 Cooke W. E. and Hill C. Pneumokoniosis due to Asbestos Dust J. Roy Micr Soc 47 232 1927 Cooke W. E. and Hill C. .: Pneumokoniosis Caused by Asbestos Dust Brit Med .. 890 1927 Cooke W. MacDonald S. Found in Asbestos Workers Oliver T Strange Bodies Lancet 136-137 1926 Cooke W. E. and Hill C. .: Further Observations on Pul- monary Asbestosis with Special Reference to Dust and Curious Bodies found in the Mier Soc 15-19 1930 Lungs Asbestos J. Roy 26. Davis G. Salmonsen E. M. Earlywine Earlywine J. The Pneu- monokonioses Silicosis Bibliography and Laws Ind Medicine Inc. Chicago 1934 Dewirtz .: Warts from Mineral Vestnick Derm 243-247 March Hyg 125 1931 Substances Roussky 1930. Abstr J. Ind Dhers .: Amiante et asbestose pulmonaire La med du trav 147-172 187-209 1930. 1931 Abstr J. Ind Hyg 13:49 Donnelly J. Pulmonary Asbestosis 1275-1281 1930 Am J. Pub Health 30. Drinker .: Alternating Current Precipitators for Air Analysis J. Ind Hyg 364-370 1932 Sanitary 31. Drinker .: The Size Frequency and Identification of Certain Phagocytosed Dusts J. Ind Hyg 305-316 1925 Effect of Asbestos Dust on Workers Health in Asbestos Mines and Factories Labour Gaz 761-762 1911-1912 Ottawa Ellman .: Report on Cases of Pulmonary Asbestosis Roy Soc Med 526 541 699 1930-1931 Proc Ellman .: Chest Diseases in General Practice H. K. Lewis 1932 p 116 London Ellman .: Pulmonary Asbestosis Lancet Feb. 4 1933 p 252-253 Abstr J. Ind Hyg 15:43 1933 Ellman .: Pulmonary Assis Assis Assis Clinical Radiological and Pathological Features and Associated Risk of Tuber- culosis Infection J. Ind Hyg 15 165-183 1933 Fahr .: pneumokoniose 1914. Hamburg Aertzl Verein March 3 38. Fahr .: Asbestosis Klin Wehnschr 1114 1932 39 Feil A Asbestosis in Asbestos Workers Professional As- bestosis Press^' Med 39 1931 1872-1874 30 40. Feuerstack veolen be schrift 18 41. Fulton W. Asbestosi bestos Di try 1934 42. Gardner . mental | Dust t J. Ind 1 43. Gerbis II f inn M 44. Gerbis H med W 45. 46. 47. German W 1932 Glovne S. Asbestos Glovne S. Referenc 1930 in Sput 1931 49. Glovne S. 399-4 50. Gloyne S Case of 51 51 52 53. 54. Gloyne S. Glovne S Lung Glovne S. Tuberc Hyg 1 Gordon 1 639 19 55. Green 11 tion of Frankl 56. Green H Numbe Hyg 57. Haddow Brit N g Curious Bodies led J. 1 656-657 niosis due to As1927 miosis Caused by Strange Bodies 136-137 1926 ervations on Pulnce to Asbestos Lungs J. Roy Feuerstack Ueber das Verhalten des Epithels der Lungenal- veolen bei der fibrin^sen Pneumonia Gottingen Preiss- schrift 1882 41. Fulton W. B. Houtz R. .. Dooley A. Matthews J. .: Asbestosis Part The Collection and Counting of Asbestos Dust Spec Bull 37. Pa Dept. Labor and Indus- try 1934 Gardner L. U. and Cummings D. mental Pneumokoniosis V1 .: Studies on Experi- Inhalation of Asbestos Dust Its Effect upon Primary Tuberculosis Infection J. Ind Hyg 65-81 97-114 1931 Gerbis H. and Ucko Ueber Asbestosis der f inn Med z Berlin Sitz v Dec. 7 1931 Lungen Ver L. The Pneuand Laws Ind Gerbis H. and Ucko Asbestosis of the Lung med Wchnschr 285 1932 Deutsche tances Roussky Abstr J. Ind TC La med du Ind Hyg 13:49 German Work on Pulmonary Asbestosis Lancet 3 92-93 1932 Gloyne S. .: Presence of Asbestosis Fiber in Lesions of Asbestos Workers Tubercle 404-407 1929 Gloyne S. .: Reaction of Tissues to Asbestos Fiber with Reference to Pulmonary Asbestosis Tubercle 151-153 1. Pub Health tors 132 for Sanitary Sanitary tification of Cer305-316 1925 4th in Asbestos 1-762 1911-1912 1930 Gloyne S. .: Method of Staining Asbestosis Bodies Found in Sputum of Asbestos Workers J. Ind Hyg 85-86 1931 Gloyne S. .: Formation of Asbestosis Bodies 12 399-401 1931 Tubercle Gloyne S. .: Presence of Asbestosis Bodies in Faeces of Case of Pulmonary Asbestosis Tubercle 158-161 1931 Gloyne S. .: Asbestosis Body Lancet 1 1351-1355 1932 Asbestosis Proc Gloyne S. .: Infra Photomicrographs of Asbestosis Lung Tubercle 14 208-209 1933 actice London Gloyne S. .: Morbid Anatomy and Histology of Asbestosis Tubercle 455-401 493-497 550-558 1933. Abstr J. Ind 1. Feb. 4. 1933 Hyg 127-128 1933 Gordon B. Jr Asbestosis Pennsylvania Med J. 637- 639 1932 ane 1caRliskRadoifolTougbiecra-l 55. 55. Green Henry A Photographic Method for the Determina- nro 3. 1933 tion of Particle Size of Paint and Rubber Pigments J. npieenste: Verein March 3 Franklin Inst 637-666 1921 56. Green H. .: Some Accurate Methods of Determining the Number and Size Frequency of Particles in Dusts J. Ind 1114 1932 Hyg 29-39 1934 Sate Professional Professional As- 57. Haddow A. C Clinical Aspects of Pulmonary Asbestosis HON, Brit Med J. 580-581 1929 Non 31 An 58. Hatch T. Warren H. Drinker .: Modified Form of the Greenburg Impinger for Field Use with a Study of its Operating Characteristics J. Ind Hyg 301-311 1932 74. Merewether Asbestos Asbestos 1930. Ai 59. Hatch T. and Pool C. .: Quantitation of Impinger Dust Samples by Dark Field Microscopy J. Ind Hyg 177- 191 1934 60 Holtzmann .: Die Einwirkung des Asbeststaubes Zentralbl f Gewerbebyg 225-220 1931 75. Mills R. G 1930 76. Mussa G. N amiante P. 133-13 61. Industrial Directory 1931 Edition Affairs Harrisburg Pa Dep't of Internal 77 Oliver .: Ind Hys 62. Katz and Slater The Second Positive Wave of the Complex Arch Int Med 55 No. 1 Jan. 1935 R 63. Kettle E. H Interstitial Reactions Caused by Various Dusts and their Influence on Tuberculous Infections J. Path and Bact 35 395-405 1932 78. Oliver .: 1026 1 79. Oliver .: 80. Oliver T. Rev. 31 64. Knopf A The Quantitative Determination of Silica in Dusts U. Pub Health Quartz Free 1933 Reports 48 183-190 81. Oliver T. Arch i Palmieri ... 82 Palmieri aie,al Kruger E. Rostoski O. Saupe .: Asbestosis Arch f Gewerbepath u Gewerbehyg 558-590 1931. Ind Hyg 144 1932 Abstr J. 83. Pancoast Roentge pa 66. Lanza A. J. McConnell W. J. Fehnel S. W Effects of the Inhalation of Asbestos Dust on the Lungs of Asbestos Workers A Preliminary Study U. Pub Health Reports 1-12 1935 84 1926. Pancoast comost- jes A OESok 67. London Letter Pneumonoconiosis Caused by Asbestos Dust J. Am Med Assn 304 1927 . 85. Pancoast cal \ portanc em Lovisetto D Asbestosi In Studi sulla pneumaconiosi in Italia 1930 p 115-132 Istit Poligr dello Stato Rome 86. Parsitano > 139 19 renaw Lyanncdh LKu. nMg. aJn.d A SmmitMheWd. AA ssnAsb9e5st6o5s9i-s66B1odi1e9s30in Sputum 87. Pidgeon eH4 Lynch K. M. and Smith W. A Pulmonary Asbestosis 11 Abstr sae Including a Report of a Pure Case 23 Am Rev. Tuberc 88. Policard 643-660 1931. Abstr Ind Hyg 241 1931 Provoc eer 71. MacDonald .: Histology of Pulmonary Asbestosis Brit Med J. 1025-1026 1927 d'amia franca d'histo 72. Merewether E. .: Occurrence of Other Pulmonary Fibrosis and Pulmonary Affections in Asbestos Workers J. Ind Hyg 198-222 239-257 1930 1930 89. Price C. Heat 73. Merewether E. R. A A Memorandum Tubercle 15 69-81 109-118 152-159 1933 on Asbestosis in Do 90 Fulmona 32 91. Pulmonary Disease Caused by Asbestos Dust 1% Monthly Lab Rev. 30 292 1930 92. Pedley F. .: Asbestosis Canad l'ub Health J. 576-577 1930 93. Recent Studies of Pulmonary Asbestosis in Germany Monthly Labor Rev. 541-542 1932 94 Reports on Conference Between Employers and Inspectors Concerning Methods for Suppressing Dust in Asbestos Textile Factories K. Home Off H. M. Stat Off London 1931 Ross J. G Chrysotile Asbestos in Canada Bull 707 Canad Dep't Mines 1931 Mines Branch Rostoski O Asbestosis Verhandl d Deutsch Gesellsch f inn Med Kong 334-338 1931 Saupe .: Ueber Lungenasbestose Wehnschr 979 1931 M^...nchen med Scarpa L. .: Industria dell'amianto e tubercolosi XVIII Congr d soc ital di med int Rome 1908 99. Sch3u4s7t5e1r-7N5.7 .1:931Asbestosis in Dog J. Path and Bact 100. 101. 102. 103. 104. 105. 106. 107. 108. Seiler H. .: A Case of Pneumoconiosis Result of the Inhalation of Asbestos Dust Brit Med J. 982 1928 Seiler H. E. and Gilmour M. .: Asbestosis Case Med J. 11112-1114 1931 Brit Simson F. W Pulmonary Asbestosis in South Africa Brit Med J. 885 1928 Simson F. W. and Sutherland A Bodies in Sputum Specimens from Fifty Workers in Asbestos Mill J. Path and Bact 1-4 1931 Soper W. .: Report of a Case of Asbestosis and Review Am Rev. Tuberc 22 571-584 1930. 13 49-50 1931 Abstr J. Ind Hyg Sparks J. .: Asbestosis Radiology 1249-1257 1931 Sparks J. V Pneumoconiosi Med J. 363 1932 m Asbestos Workers Brit Stewart H. L. Bucher C. J. Coleman E. .: Asbestosis Two Cases Arch Path 909-916 1931 Stewart M. .: Pulmonary Asbestosis Brit Med J. 675 1928 109. Stewart M. A Method of Examining the Sputum for As- bestos Bodies Brit Med J. 581 1929 34 110. Stewart M. .: Pigs after t J. Path and } 111. Stewart M. J. au of Pulmonar 509 1928 112. Stewart M. J. Peculiar ... Bodies in M Sputum J. 113. Stewart M. .. Clumps of 114. Ind Hyg 13 Stock G. A Admin 10 115. Terreil .: ayant aspe l'action des des s^'ances - 116. 117. Timmermans 280 307 1 Tylecote F Lungs of C Case Lanes 118. 119. Wahlstrom E. Mineral 19 1934 Wood W. B Skiagrams + 10 353-363 120 121 122. Wood W. B. Wood W. B Lancet De 17:33 17:33 1935 Wood W. 448. 1930 124. 125. plicated by Abstr J. I Wood W. 10 457-460 Wood W. B. culosis Tw 11 157-158 Dust Monthly Lab Health J. 21 576-577 in Germany Month- oyers and Inspectors v Dust in Asbestos 1. H. M. Stat Off ada Mines Branch Deutsch Gesellsch f M^...nchen = med tubercolosi 1908 XVIII 110. Stewart M. .: Asbestosis Bodies in the Pigs after 3 to 5 Months Exposure in an J. Path and Bact 33 848 1930 Lungs of Guinea Asbestos Factory 111. 112. 113. Stewart M. J. and of Pulmonary 509 1928 Haddow A. .: The Immediate Asbestosis at Necropsy Brit Diagnosis Med J. Stewart M. J. and Haddow A. .; Demonstration of the Peculiar Bodies of Pulmonary Asbestosis Asbestos Bodies in Material Obtained by Lung Puncture and in the Sputum J. Path and Bact 172 1929 Stewart M. J. Tattersall Clumps of Asbestosis Workers J. Path and Ind Hyg 15:78 1933 N. Haddow A. .: Occurrence of Bodies in Sputum of Asbestos Bact 737-741 1932. Abstr J. 114. Stock G. .: Pulmonary Admin 126-129 1933 Asbestosis Med Bull Vet 115. Terreil .: Analyse d'une chrysotile serpentine fibreuse ayant l'aspect de l'asbeste silice fibreuse r^'sultant de l'action des asides sur les serpentines C. r hebdomadaires des s^'ancesde l'acad des sc Paris 100-251 1885 J. Path and Bact ~ Result of the In- _ .. 982 1928 116. 117. Timmermans F. D Asbestosis Zentralbl f Gewerbehyg 8 280 307 1931 Tylecote F. E. Lungs of Coal Case Lancet and Dunn J. .: Asbestos Miner who had Never Worked in 632-633 1931 Bodies in Asbestos bestosis Case Brit vy South Africa Brit 111 .: Bodies in ers in Asbestos Mill 118. 119. 120 Wahlstrom E. .: An unusual Occurrence of Asbestos Am Mineral 178-180 1934. Abstr Chem Abstr 28 6088 1934 Wood W. .: Asbestosis Radiographic Appearances in Skiagrams of Chests of Workers in Asbestos Tubercle 10353-363 1929. Abstr J. Ind Hyg 210 1929 Wood W. .: Pulmonary Asbestosis Tubercle 10:23 1929 bestosis and Review Abstr J. Ind Hyg 121 Wood W. B. Lancet Dec. 17:33 1935 and 22 Gloyne S. .: Pulmonary 1934 p 1383-1385 Abstr J. Asbestosis Ind Hyg Wood W. B. and Gloyne S. .: Asbestosis Lancet 4451240-1257 1931 448 1930. Abstr J. Ind Hyg 146 1930 ed stos Workers Brit Wood W. B. and Gloyne S. R Pulmonary Asbestosis Com- oT plicated by Pulmonary Tuberculosis Lancet 954 1931 a .: Asbestosis Two Abstr J. Ind Hyg 14:66 1932 ce Brit Med J. 675 Wood W. B. and Page D. .: Asbestosis Case 10 457-460 1929 Tubercle Se : the Sputum for As- 29 Wood W. B. and Page D. .: Asbestosis Death from Tuberculosis Two Years after First Exposure to Dust Tubercle 157-158 1930. Abstr J. Ind Hyg 146 1930 35 e a cidence of asbestosis with relation to occupation concentration of the dust and length of exposure in the fifty persons examined in this study is indicated in Table XI Obviously the examination of such relatively small group prevents the formation of definite conclusions as to the influence of these factors Nor is it possible from our findings to establish the maximum safe concentration of asbestos dust in the air However the results of this investigation show the necessity of a reduction of the dust concentrations in those operations shown in Part II of this study where there is continuous exposure to high concentrations SUMMARY 1 The concentration of dust in asbestos fabricating plants depends primarily on the grade of asbestos mill fiber gives rise to a higher concentration than crude fiber Operations arranged in decreasing concentration of dust are preparing carding weaving spinning twisting winding and warping 2 The average particle size of asbestos dust is stated in two diameters longitudinal and transverse 3 Petrographic analyses of dust encountered in asbestos fabricating plants collected in the workers breathing zone shows it to contain no free silica 4 Fourteen or 25 of fifty workers employed in the textile departments of asbestos fabricating plants in Pennsylvania had both clinical and roentgenological evidence of asbestosis ACKNOWLEDGMENTS The Department of Labor and Industry of the Commonwealth of Pennsylvania wishes to thank the management and employes of the plants studied for their cooperation and interest which made the success of this study possible Dr. H. K. Pancoast and Dr. E. P. Pendergrass of the University of Pennsylvania whose interpreta- tions of the films have been used Dr. G. W. Grier of the University of Pittsburgh for his interpretation assistance and advice in the roentgenological study Dr. J. Evans Scheehle Secretary of the Pennsylvania Department of Welfare in extending to the Department of Labor and Industry the facilities of his department Dr. C. A. Laubach roentgenologist and cardiologist of the Norristown State Hospital for doing a large majority of the ray work and his technicians for the routine laboratory examinations Dr. D. Heard and Dr. A. B. Fuller of the University of Pittsburgh and Dr. C. C. Wolferth of the University of Pennsylvania for their assistance and interpretation of the cardiograms BIBLIOGRAPHY 1. Amiante Hyg du trav 191-192 1930 2 Anderson I. V. and Clark G. .: Application of rays in the Classification of Fibrous Silicate Minerals Commonly Termed Asbestos Ind and Eng Chem 21 924-933 1929 28 3. Auribault dans les trav p 4. Baader E. med We 5. Beger P. Arch 2 6. Beger P. 1 530 539 7. Beger P. Med Kl J. Ind 1 8. Beintker i behyg 9. Beintker 1 1934. A 10. Bowles ( U. B. 11. Bridge J. of Fact don 19 12. BromleyD -A D Asbesto Radiol 1934 13. Buttner asbest muss 14. Cirkel ' tion A Dep't 15 Clynes 16 Cooke Asbest 17 Cooke W 18 Cooke V 1928 19. Cooke V Pulme Abstr Hyg 20. Cooke \ Lungs 1931