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/ur). 21 hi \ 4. fizz COMMONWEALTH OF PENNSYLVANIA Department of Labor and Industry RALPH M. BASHORE, Secretory Special Bulletin Xo. 42 ASBESTQSIS jr*- Part II. The Nature and Amount of Dust 't Encountered 'in Asbestos Fabricat* ing Plants. Part III. The Effects of Exposure to Dust Encountered in Asbestos Fabricat > ing Plants on the Health of a Group of Workers. BUREAU OF INDUSTRIAL STANDARDS * JOHN CAMPBELL, Director Harrisburg, Pennsylvania September 30,1935 K. ' ' ' '. '. ' COMMONWEALTH OF PENNSYLVANIA Department op Labor and Industry t Asbestosis Part IL The Nature and Amount of Dust Encountered in Asbestos Fabricate mg Plants. Part IIL . The Effects of Exposure to Dust Encountered in Asbestos Fabricat ing Plants on the Health of a Group of Workers. . by William B. Fulton, M. Dm Chief ofIndustrial Hygiene Allan Dooley, Chemist Jvua L. Matthews. Ph. D.* Chemist Roust L. Houtz, Chemist % INDUSTRIAL HYGIENE SECTION BUREAU OF INDUSTRIAL STANDARDS ASBESTOSIS--Pa Encounter j In 1934 the Depart weaith of I\*nn.svivai: to the health of work Pennsylvania. The D of the literature at th the general subject o lack of information, t! i their cooperation was I include an evaluation gree of dustiness and * I agreement was mad neither would be give ings of any particular employes *in this stu- being recorded. All r of the Department of Asbestosis was first (16) at the Glaring C . *f in 1924 reported a cas< dergrass (S3) in 1926 < ers. Since then, other of asbestosis, but it w (74) published the res ers, together with som< McConnell, and Fehtu report of a comprehcn The industry in thh plants engaged in the suiating tape, asbestos ucts. According to tin there are approximate!, t facture of asbestos pro ! The nature of asbes i procedures used for ot i accepted standard met I ing. and particle size < report (41) the meth* countered in this stud} * Sataota of >iut ttkm fa aoril&nj fora of tfw* Mavlir amifum. In il*i <UtUM w#in* * *< o(Uml ottotoorttofehnltfitturc mirfonpu*f't***^'* Ml mttataM) ron*ot aflrr tf ot tatter Urns*, is Mta > i1 f?t--4 T t l% l T'V* 1- ? of Dust Fabricate ? to Dust ? Fabricat' fa Group i-idustrial Hygiene i > * * 4* k f 1' Hh ASBESTOSIS--Part IL The Nature and Amount o Dust Encountered in Asbestos Fabricating Plants. . Introduction In 1934 the Department of Labor and Industry of the Common wealth 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 pneumokouiosis. 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) m 1924 reported a case of pulmonary asbestosis. Pancoast and Pen dergrass (83) in 1926 examined a group of seventeen asbestos work ers. 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 work ers, together with some evaluation of the degree of exposure. Lara, 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 doth, brake lining, ip- saiating tane. asbestos rope and wick, and other misceHan** pTM*- jtcla. According to the 1931 Pennsylvania Industrial Directory (61) there are approximately two thousand persons engaged in the 'manu facture of asbestos products in Pennsylvania. The nature of asbestos dust is such that many of the standard procedures used for other dusts could not be used. Changes in the aeeepted 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.* SampMe of dost taken is ousts for fabrtestfac asbeatoa products w*ra eofleeted by t artlflnl font of the rtudard method, uste* i M per cent ft. 3. p. ethyl akuboi as a Wittmi. Is (Ida medium ttm partMrs were well <burdened amt rradilr mooted, wve atlhd motor was utilised as the coUrettar awdtom. accJoateratloo nreurred Itnmediate;?. MM mode coosttetr Impossible. Dtopmww ( tno duet ia aJcobui is ruud. A eettiin* time of at host tbtnr aduute* was tmotml before touatm. The particle sonat ia toy yiten Said maalaed rosatoot after this parted. A modified Mater is described, it is mastrueted of Imthsr suapo, hi such way that Urn fluid la tha boulter flask is rtsibie at ad tiaas. . .3 *' Xi Preliminary 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 pies collected would be representative of the actual exposure to dust. Psomras or Asbestos The term "Asbestos" in its commercial sense is loosely applied to a group of minerals with a number of sub-divisions having, m com? mon, fibrous structure, and possessing more or less resistance to the action of fire and add. The three mineral groups are: 1. AnthophyUite--(Mg.Fe) SIO*. 2. Amphibole or Hornblende--Silicates of Fe, Ca, Mg 3. Serpentine--3MgO.2SiO*^Ha0. The three types of asbestos ordinarily used in manufacturing are chrysotile, crocidoiite, and amosite. Croddolite (blue asbestos) and amosite, a yellow or brown variety of croddolite, both belong to the amphibole or hornblende group. The prindpal source of the latter two varieties is, at present, Rhodesia, South Africa. Chryso tile, a 'mineral of the serpentine group, comprises the bulk (about 95^) of the asbestos of commerce. Only relatively small amounts of croddolite and amosite are used in comparison to the quantity of chrysotile. The prindpal source of chrysotile is the Thctford region of Can ada. about forty-five"miles south 6f Queocc. Inc united States does notrank high as a producer of asbestos, the domestic output being less than three per cent oi the amount used in its asbestos manu facturing industries (10). No asbestos is mined in Pennsylvania, although smalt amounts have been found in serpentine quarries from time to time. No attempt has ever been made to separate the asbestos from the serpentine in these quarries. Arizona and Ver mont supply the bulk of asbestos mined in this country. table r-rmcAi axalt*bs or csrysotzls 8Sa** No. Tal StOa 1 UcO > ro ! IMi HaOa i **% , 1.41% S.7% t nj* ! 4S.1S mi 4 .............. mM 4LM *-* 9MS m.tt - MS MS Ml S .......... . 4M7 UM i tM. MS UM : MS Mi mj* 1 ** _ - 4S.43 :- J - M* , IM Comb. B*0 IMS* IMi 14.37 1M7 . IMS 14.08 U.87 U.4 . i \ i i In the Canadian deposione-eighth inch to six inc serpentine rock. The imu. lustrous color, although filaments, they arc white greasy and slippery to th a single fiber like cotton i. Chemically, chrysotile i small amounts of oxides published analyses of clthey appear to van* but i; of chrysotile (95).* The does not exist as free si: bases in a complex mol. workers' breathing zone analyzed pttrographicallv The chrysotile of com depending on the length hand-separated and -sdc unfiberized form. Mill IV mechanical crushing of aration of the fiber. Cr is 4 inch and longer; C up to y inch. Alill fib length. The spinning quality length. Consequently, t from the crude fiber. T of textiles and in the m: ter, and cement. D Preparation--Crude f gone no treatment othc from the fiber, after wit at the plant in burlap The fibers must first be tides. This operation a "preparing room." . are opened and dumpc fiber is fed into rim-w minutes. These cmsl radial axle, and revolve is placed. After the f cientlv, they are fed usually of the Saco-Lc open the fibers. From a rectangular shaker material, and some of from the screen by air then ready for mixing P*trocT*phK astir*** of *a Snttcw lubofmtorr, Vvonayl? *V/*TV**< f i v ; |st samples In each -al information was . . ;`.Iwith special refer . :: Ind types of opera- >-Vi jjtermined for each :r> -;Xvjach operation was yi^ ^.jproximate time re"'\>ta,..cess1 so that sam ' ' -"''Actual exposure to $s loosely applied to ihns having, in coml less resistance to groups are; k t U Fe, Ca, Mg i manufacturing are i(blue asbestos) and vite, both belong to cipal source of the 'th Africa. Cbrysor es the bulk (about fvely small amounts (>on to the quantity ;-ford region of Can* U United States does 'mestic output being - its asbestos raanu:td in Pennsylvania, i serpentine quarries hade to separate the , Arizona and Ver{: country. '<rmx ; alto* mt% \ w* Ml t Me v mi 1 Ul Coab. H*0 U4s 11.9 M-3T IMS H. !t8 a.<s ' . In the Canadian deposits the chrysotilc is found in veins from one-eighth inch to six inches in length, occurring as bands in the serpentine rock. The mineral is generally a dark to blackish-grecn lustrous color, although when the libers are sqinratcd into fine filaments, they are white. The fibers are very fine, silky, soft, greasy and slippery to- the touch. They cannot be separated into a single fiber like cotton or wool. Chemically, chrysotilc is a hydrated silicate of magnesium with small amounts of oxides of iron and aluminum. There are many published- analyses of chrysotilc from the Thetford region, and they appear to vary but little. Tabic I gives eight typical analyses of chrysotilc (95). The silica shown in the analyses in Table 1 does not exist as free silica. It is chemically combined with the bases in a complex molecule. Samples ot dust collected in the workers* breathing- zone with the electric precipitator (30) were analyzed pctrographically and were found to contain no free silica.* The chrysotilc of commerce is classified in two general grades, depending on the length of the fibers. Crude fiber consists of the hand-separated and -selected material essentially in its native or unfiberized form. Mill fiber includes all grades that arc obtained by mechanical crushing of the rock and subsequent mechanical sep aration of the fiber.. Crude Xo. 1 consists of fiber whose length is Y* inch and longer; Crude Xo. 2 ranges in length from y inch up to ^ inch. Mill fiber includes all fibers less than y 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, pacer, plas ter. and cement. ] `" PgSCtlPYIOX OP PXOCSSS Preparation--Crude fiber as received from the mines has under gone no treatment other than hand-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 par ticles. 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 proparing room. The fiber is fed into rim-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 suffi ciently, they are fed into the hopper of an opener or fiberizer. usually of the Saco-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 readyJor mixing with cotton. . 3*t*amphtt t tamokt mi Mortotud by Dr. A. Z. QiSony. el tbs labeemat BlliiM Laboratory. .INiwyh mie Dtpertacst o( Leber sab Iabustry. .5 ' i V t' f . . . .I . ' ^ Mil! fiber, because of the mechanical crashing* and separation given it at the mine, docs aot require the preliminary processing in the rim-wheel crushers as does the crude fiber. The mill fiber is ' v . f fed directly into the Saco-LotveJl opener, and from then on is given L | the same treatment as the crude fiber. * Asbestos fibers when examined microscopically do not possess :- ^ -v* 1 'the rough imbricated surfaces of other fibers such as wool. They resemble fine polished metal rods, tree from any serrated surfaces. ' This characteristic explains the extreme difficulty encountered in : T: & attempting to spin a thread of pure asbestos. A certain amount - f 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 asbes- f tos used in the manufacture of products made in the four plants * included in this survey. . . TABLE H-TEBCE5TAOES OT ASBESTOS IX VABIOC1 ASBESTOS PB000CT8* f' 1 mat Rut Ptasv Rut ? Xatutil *A s o o ; ante Bata* (woreo) ........................... .. U-H i Couumlai srtdt jin ... .............. - .. >' 6er*t. aptrli. 7*ra toil dots ....... ,. i.. .. m-H t Tam tad dots. Umknrtttm Sp. -- - ... -- AjbWtOi CMKStS -- Brtfco ttatef (uoidwJ) .. : AAmim paper ............ ............ .. . WU sacsota temlatioti ........ -- . .. .. CffQrt Mot tatocm*Uom luppMtJ Or tt* If IS tt a MS .. # .. a .. -- u> a .. 00% 80-96 awco .. -- -- _ M If .a \ Mixing--Weighed quantities of asbestos and cotton, and usually ! some small amounts ot 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 mix ! ing, the batch is run through the same picker twice, or through ; two pickers arranged in series. The mixture is removed by suction i to the storage bins to await carding. ~ ,, Carding-Carding is necessary to remove the remaining small r bits of rock, and to comb the fibers into a more or less parallel cont dition so that they may be spun. A card is a machine with a series | of revolving cylinders covered with strips of leather, wound di agonally, and fitted with fine, close-set. sharp steel bristles. A card- 1 ing unit, as used in asbestos plants, usually consists of two cards, \ the breaker and the finisher; The mixture of asbestos and cotton *` i % \ i . '6 s'.' ' ' is wheeled in hand trttcl I into the feed hopper of t volving cylinders of the loose blanket or web. through ninety degrees. 1 finisher card.* The fiber | . finisher onto a moving ! i scrapers or rubbers com j unspun yarn. Those ro\ taken to the spinning de The rovings at the ex* i spinning purposes becati: are gathered up as card sequent operations, retur is shredded and added t Some cards are dcsigi corporated into the rovi: practice yields a strong* In the manufacture o used. The rope and wic arc thicker than yam ro i ficicnt. Generally a fibc j manufacture is used for j Spinning--The unspu* necessarily have no tw: is necessary to twist o strength. This spinning or on a machine called r , all the spinning was d plants had spinning fra: ! The mules had from ] dred and fifty spindles ; which is made to uiovt from the cards arc mout j fastened to the spindle i spools (a maximum diV 1 arc unwound. The spi j slight twist to the rovi ! point of greatest races- yam spun. When suf carriage moves back an* ing the spun yam fab i spindles. The operatic J ful!v wound with single | The duties of the mi j the mule when thev a: 5 unspun rovings as the > constant vigiicncc. l>cca | Subsequent Operatio [ transferred to a spoolir ! ply yam on other tvp I transfer of the yam.* 1: iig and separation |narv processing in 5 The mill fiber is $n then on is given _y do not possess ?*Ji as wool. They | serrated surfaces. Ay encountered in JA certain amount 'gng. The amount "*which the finished I amount of asbes* ?inthe four plants iJESTOtf PSODCCTS* t Ptaat Pteat. 0D n-a% m .. _ 90% MS MOO MOO -- -- ;-- 1M0 * .. * -- -- -- SB IS --* n Mton, and usually ;:n alternate layers ;Iy in front of the V picker, which is ore thorough mix* ;twice, or through irraoved by suction >; remaining* small {: less parallel con* i:hinc with a-series pather. wound di ?* bristles. A card* fists of two cards, stos and cotton i i is wheeled in hand trucks from the storage bins, and fed by band 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-back 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 sjk>o!s to be tajecn 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 sub sequent 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 in corporated into the rovings as they are dolled from the card. This practice yields a stronger roving. * 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---The unspun rovings, as they are dolled 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 or on a 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 thev were not in operation. . The mules had from two hundred and sixty to possibly five hum 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 tltc rovings fastened to the spindles. As the spindles recede from the Jack spools (a maximum distance of about fifty-four inches') the roving? 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 arc turned very rapidlv. and the yarn spun. When sufficient twisting has been done, the spindle carriage moves back annin in the direction of the Jack spools, caus ing the spun yarn (about fiftv-four inches) to be wound on the spindles. The operation is then repeated until the spindles arc fully wound with single-ply yarn. The duties of the mule soinner are to remove the spindles from the mule when thev are filled, and to tie the broken ends of the unspun rovings as the spindles recede. Tills last operation requires constant vigiicncc. because the rovings are continually breaking. Subsequent Operations--The spindles from the mules arc next transferred to a spooling or winding machine to rewind the single- ply yarn on other types of spools. This is simply a mechanical transfer of the yam. - * T T --* -..- ............ ..v . ................................................... . .. ...............................* * , t These spools are next taken to a twisting machine where two or three of the single-ply threads are twisted into one thread. For the manufacture of brake lining or packing the vara may be re inforced with a fine metallic wire. This addition is performed dur ing the twisting operation. The twisted yarn is finally wound on paper spools about six inches long. The twisted yarn may be sold as such to other manufacturers, or it may be woven into doth, 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-ply yarn with a very low cotton content is used. Most tape looms are constructed 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. Goth is woven in much the same way as insulatine* tape. Two- or three-ply yarn is used. Sometimes the vara 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 wen 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 pasoline to which other ingredients may be added. Tinal operations in the manufacture of woven textiles consist of calendering, inspecting and winding of the products. These opera tions are all mechanical ones, and require no description. Gasket Making--One of the important uses of asbestos cloth is in the manufacture of ring gaskets. In this process, the asbestos doth is spread on the fioor and impregnated with a solution of rub ber in gasoline, to which has been added barytes and other pig ments. The rubber-treated asbestos eloth is. cut into strips of nredetermined 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 arc made by braiding asbestos yarn on spetially designed machines. * Oram Processes . Other products containing asbestos are made in some of the plants included in this survey. These products include asbestos paper, in sulation 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 IL .` . 8 * j j j j j j i j ! j [ j j j . PATt Cooke and Hilt (22) found particles in the 1 sixty microns in length, average particle size of length, were measured. Methods of Particle .three general mcthixis 1 particles. One method, micrometer inserted in made by moving the tmV to determine the dkimet- The second method, ; (55) to determine the s since been applied to th dustrial dusts. Jn this ; of the sample are made by a stereopdean on a images are measured ar readings. . With the third me du slide, and the images p micro-projection appamt method is the one used more fully in a later parr Nature of Asbestos D( nesting plants is non-n: three types: particles ui fibers; and cotton fibers. figure: r. : FROM AN PLANT. MA | ) >. I*. : c ft Jiine where two or lone thread. For yarn may be re'y is performed durI finally wound on 1 manufacturers, or or braided in the ' .Iar manner to the ! 1- In the weaving n/ single-ply yam ?,pe looms are con* y be woven at the Jbestos tape to wet fag. The warp is %( Ratine tape. Twol: is reinforced with ? or both the warp Ving on the use for -inner as tape. As t at the same time. Jnpregnatcd with a ^tension of gilsonite jded. { textiles consist of :cts. These operaicnption. asbestos cloth is -jccss. the asbestos a solution of rub les and other pig ; into strips of nre^d. They are then dor shipment. An .ting thick rovings j packings arc made Machines. } ` . i . i some of the plants Iasbestos paper, in&es, lumber, molded ^ ^generally electrical J for these purposes : * used in these ar '| | '^ >. i }t j i li % | tii i i i t ! Particle Size Determination Cooke and Hill (22), in autopsies of asbestos workers, have found particles in tnc lungs measuring up to three hundred and 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--Within recent years .three general methods have been used for measuring the size of particles. One method, a direct one, involves the use of the filar micrometer inserted in a microscope tube, measurements being made by moving the micrometer adjustment and reading the vernier to determine the diameter of the particles. 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 arc then projected by a stereoptican on a screen at a known magnification. The images are measured and the average size calculated from these readings. . With the third method, the dust is collected on a microscope slide, and the images projected on a ground-glass screen with a micro-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--The dust encountered in asbestos fab ricating plants is non-uniform in nahtrT It IS Seen tp nf three types: particle* more or 1m* spherical in shape; elongated fibers; and cotton nbers: Figure 1 is a photomicrograph of dust pro- FJGURE t. PHOTOMICROGRAPH OP OUST PROM AN asbestos FABRICATING PLANT. MAGNIFICATION 600 DIAMETERS 9 r - ...... . -- ..........*- i* ' *. * ' .' f. - .-- t ' 8 duced when processing mill fiber. The three types can be readily noted. . Because of the non-uniformity of this type of dust, average par* tide size was determined in two dimensons. one at right angles to the other. Measurements were made of the longest diameters, which were termed longitudinal diameters, and a second set of measurements were made at right angles to the first, which were termed transverse diameters. Method of Collection--Samples for the determination of particle size were collected by the use ot the electric precipitator (30). This method yielded samples that were satisfactory for direct micro* projection and measurement. No intermediate steps for preparing .the sample were necessary. The precipitator employed was designed on the prindple of the Cottrell precipitator. The air was drawn through the precipitating tube by a small rotary fan driven by a motor, the rate! of flow being measured by a flowmeter. The rate of sampling was one cubic foot (284 liters) per minute. The precipitating tube was made of Pyrex glass with an inside diameter of 2.4 cm. A number 1 microscope cover slip. 22 by 70 mm. in size was placed in the precipitating tube directly beneath the central electrode. The dust in the air was deposited electrically on this cover slip. When a representative sample had been precipitated, the cover glass was removed and mounted dry on a microscope slide. A total of sixteen samples was collected at various operations, all being taken in the breathing zone of the workers. . . - Measurement--A micro-projection apparatus with the microscope arranged in a horizontal position was used. Apochromatic objec tives, 8 mm. and 2 mm., and a 10 x compensating eyepiece were employed. This system practically eliminated color fringes, gave a fiat field, furnished maximum light intensity, and permitted the measurement of the long fibers. The images were projected on a ground-glass screen at a pre determined distance from the microscope. This screen was ruled in centimeter squares to facilitate measuring. A transparent rule was used, and the size of the projected images recorded in milli meters. Accurate focusing on each individual particle before meas uring was accomplished by a remote control attached to the fine adjustment of the microscope by a mechanical sleeve. Predetermined magnifications of 2000 and 10.000 were used, de pending on the objective. Measurements were made according to the method suggested by H. L. Green (56). Using the 8 mm. ob jective (magnification 2000) the longest diameters of two hundred particles were measured, all lengths less than ten millimeters (five microns) being neglected. The number of fields examined was also recorded. An equal number of particles was measured using the 2 mm. objective (magnification 10,000). and all particles fifty milli meters (five microns) and over were disregarded. Again the num ber of fields examined was recorded. These measurements were used to calculate the average longitudinal diameter of the sample. The method of calculation is shown in Table 111. For the calcula tion of the average transverse diameter the same procedure was 20 i i? : .- . . . t . followed, with measurer longest diameters. TAHIJC lit--KX.UIPT.K t MicalAnttoo--90Q j; MB. a l IuS u14 14 17 IS SO St 8ss S4 a sr a a a a a a X8T 9 480 43 4S 47 8 40 a8 687 n n 1nt880oo0 iso m 140 M0 170 ITS 18 SnCoO 230 SM ! 38 i 330 <70 S.0 6.0 7.0 .# 3.0 3.3 190..00 10.3 IX.O 1121..03 It.* 13.3 14.0 14^ 13.0 16.0 17.3 13.0 - 11.4 l 19.0 1209..05 tt.O | n4 22.3 1 23.3 i 8.0 i S7.S 30.0 i 31.9 S3 ; 8.3 ; 33.0 1 36.3 i 37.3 : 40.0 i 43.5 1 47.5 ! 8.9 I 8.0 : <0.0 1 <5.0 . 70.0 ! w8..0o : ! 37.5 19000..00 i ! >03.0 ; 113.0 130.0 ! 11G33..03 18.0 Tots! ' tt 7 V3 8411 3 91 3 i 16 1 1 1 $ 1 9 1 1* t 13 ) l 3 2 4 S 9 1 S 1 1 S S 2 I 1 4 1 4 s s 1 1 1! 1 i! 1! s 1 1 t 2 ! t < Results--Particle size the dust collected at car but no appreciable vari: marked difference in the th two general grades .. jbes can be readily . I*' `. |iust. average par -7 fat right angles to .longest diameters, a second set of vf first, which were `i-i < :Hnation of particle 3,tator (30). This ` for direct micro|tcps for preparing tie principle of the ;t the precipitating y rate of flow being (Was one cubic foot h*as made of Pyrex rnber 1 microscope ; precipitating tube f.st in the air was n a representative twas removed and 'xteen samples was 'the breathing zone > ith the microscope j>ochromatic objec* ting eyepiece were -lor fringes, gave a find permitted the screen at a pre; screen was ruled <k transparent rule [ recorded in millivrticle before measItached to the fine reeve. ^XO were used, de?made according to (ting the 3 mm. ob>rs of two hundred rn millimeters (five j examined was also pleasured using the Articles fifty inilli$1. Again the nam* measurements were r-ter of the sample. For the calculafine procedure was followed, with measurements being made at right angles to the longest diameters. tabus m-cuairi.r or Mmion ckkt> nc tor calculation or AVK1UGK LONOITUIX.VAL IHAMETKK llatalfleotlo*--290 IS 7M4* MafttiSeoiloo--lOA US TteU* -- tt < ft fa Z Q MB. a f f X tt 0 . sr Ma M IT 0 S .0 00 a a a tt a a tt a a m 4S a a <7 N a m a a tt a is a a a a NO InNo mM9 nmNoO IaNo nSNo NO ao 00 0.0 1.0 14 7.0 7.0 14 (4 9.0 10.0 M.S 11.0 114 ISA It4 ISA 14.0 14A 10.0 10.0 1 17.0 N.0 ! ua ; 19.0 j IDA a.o 0.0 i 0A i BA 1 0a.Ao < 0A ! a.o ! 0A axA . SA | a.o NA 0A 40A 4SA 47A MA 00.0 N.0 40.0 70.9 N0..00 74 N.0 M9.9 N0.O 118.8 120.0 11302.94 100.0 TotoJ n 7 4 1* 1 1 0 1 0 t 1 10 1 1 1 0 1 0 i i t 1 is . : 1 S 41 0 t 1 i '1 o t t t t l4 1 4 2 0 1 1 1 1 . s1 1 1 1 00 0.0000 AH05 .09918 .10900 497N ASIC .0010 Aosa 4903 AS10 .000to .0060 .0811 .230(9 .0018 .008 .0008 .0S18 .2033 .0018 .03318 .00030 .00030 43095 .eras .0018 .00018 AS1S .13200 .A10nS1aS .03318 .1078 .005 .sm .0018 .0060 .00030 .0000 .00318 mur .1300 .03318 A32G0 .00(90 Ai0m0t4RS A0318 .0308 .83318 .0308 .0018 40048 ..0c3a3n1s8 .0305 4.0000 *48972 1.33931 9.64042 O.OSS0 9.3539) ' 0.2030 0.2074 2.3580 2.98380 9.S4SA7 1.08393 0.76318 0A07N 64700 0.447H 0.44110 0.4307 3.9700 0.8NM0 8.2012 0A9670 0.41328 1.23170 1.29S5S 4A14C0 0.09815 0.71972 2.3763 0.7790 *41800 1A3512 9.180N 1.04423 SAMIS 1.U032 8.9C190 1A9007 2.15823 2.6S30e tAins 1A**T 14080 TAMO i.oanco 0.41900 4.41100 7A6C00 241773 2.90002 2.9790 34180 3.0093 4A122S 22.040 4AB937 5.4073 4.13295 3 4 S 4 7 4 9 10 IT 13 IS 0 tt 23 0 a 10 48 04 37 0.4 37 0.8 *9 0.0 7 0.7 2 OA 10 0.9 1.0 1 0 1.2 4 1.3 1 1A 11 2.0 12 2.3 2 2A 3.0 7 34 4 4.0 1 4.3 - 1 Total 20 l.u 1.44 1.0 0.42 0.14 4.0 0.0 240 4.0 140 1.C3 21.0 4. 9.0 0.0 14. 4.044(1 101.0 MOB. LcottUi of Intac* to nSllmrtMX. tt m Leactb of partkle In rolrroas. f - iRcauxT lit* f fa - m z (Si* I t s a) + SCftsni Ararat* Diameter xi t afi 143 Stkrooa. 174.1100 Results--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 lougi- 11 ` . tudinal diameter of the <! microns, while that of diameters were 0.69 micliber respectively. The 1 drud and two microns. The percentage fretjm determined for longitudi shows these values pU> paper. The difference in the t animation of Table IV. ten microtis or more in dust occurred within thes* dust was 0.5 microns or ! fiber dust fell within thi: TABLE tv. SIZE >KK' tar Oronp in Microm Cuter 0.40 ____________ ----------------- L04L40 ...................,I --^ ^---------- ;_7_; 3.04.40 - 3.4-3.00 ______ i.O-1.40 _________ 4.S4.SO ------------------- 3.0 *ad em Dust Coni All samples were collcc Smith impinger (58) ttsir hoi as thccollccting med: the method described in were counted regardless greatest diameter averag* the total. The dust com in Table V. ij Tl 4 t 5BOM ASBESTOS FA 9. ITHAN STATED SIZE. Ljl--LONGITUDINAL :.fWhu" f,br; tudinal diameter of the dust from crude fiber was found to be 2.12 microns, while that of mill fiber was 1.35 microns. Transverse diameters were 0.69 microns and 0.-45 microns for crude and mill fiber respectively. The longest fiber observed measured four hun dred and two microns. The percentage frequencies of the various-sized particles were determined for longitudinal and transverse dimensions. Figure 2 shows these values plotted on Hazen's logarithmic probability paper. The difference in the two types of dust is further shown by ex amination of Table IV. Three per cent of the crude fiber dust was ten microns or more in length, while only 1.7% of the mill fiber dust occurred within these limits. Twenty per cent of the mill fiber dust was 05 microns or less in length, while only 16% of the crude fiber dust fell within this range. TABLE IV. StZS flUSQCEXCT OtSTBtUCTlOX OP ASBESTOS CCST sa* Omt* m UkroM Grade Tiber MIS Tibet LoacfttKtfaa! Trmarw** LoncftixUael ^ Tnairmt Vb*r .* -- .l* ISAM 1 1A4JI U4. .... 77.4 1.... 14 14 . .... J ** *-* 1A U4JI w i ----- UAff ............................ --. U-AJB . i. %& s.: -- S4 tX U tad m .......... 4. XX 46.% 24.3 7.3 4.# 4.4 s.4 1.7 L L S.0 *. : j > i . ; i : j | | T.3% -- J -- -- --- *.7 Dust Concextxatioks in* tbe Plants All samples were collected by the modified form of the Grcenburg- Smith impinger (58) using ninety-five per cent U. S. P. ethyl alco hol as the collecting medium. Dust counts were made according to the method described in Part I of this report (41). AH particles were counted regardless of size. Particles less than ten microns in greatest diameter averaged approximately ninety-seven per cent of the total. The dust counts for the different operations are shown in Table V. ' 13 1 \ t~ . *; v { l * ' S1 o s3 HI- Ii H aa si ll4 a! ai aIjUl ns a ;ss : i-a- : >4* ! iAji \ a a ia ; ta ai * as S B n aa3k m - ii a a aa aa I1 a aa< ** i:;:: i ? iiiii 3aa Mat : i; -2 i ; i iaa !ii .a a a aa a : a ai ! iaa ::: a aa i m 14 **3 1 4 4t 1 tt <4 1 * Jlffllll s .: : .: a aa aa aa aa ai ' TA B LE .Y . lU U U A R T OF D O IT COKOEKTRATIOKC IN ASBESTOS FABB1CATINO fL A M T * a s ss * I I s! 5li ii aa a g- i i i tW : i! - ii a- %22 M^ai * \ii A + j iii 4 4 14 ri j aaa m i r u aa ":: _toA! ISiia Hi t1*M 1 a2i1aMi Ia m \% u 1 ! i 4 i t S'! ' ' **3 *S 8 a ae 111 ?.. a i aaa ttk m !*s A 1 s | tia ii iaa a r* r j !i 11 i- ! 5- i: aa a a : : i Ii! iiiii ssiiiiNi* ! f iIjliiii As* i iNi33a . J t iiK5i: i t.. ill i i ?H5SS iji i 1! iij i *** | : h*5 * IIS*ff! ef ill 1jj lii 4iaa414 1 41aaaii : 1 i 4 1 a144 > 4 44 44 4 i ii aa aa a !: i4 IHU ii! a1 ijgi iifIII i * \ JS a Jlli #*i Hi n mall-f" to --*-- 99 toto s4 *** *tm X 9 F* V ASA>3 ijfiiiiH! ill 3 1 w8 mm |ll & uHfL lllJiIi in A CMSKft 5 min *Il|3 i S 4i <"imsista "a?* Iiiii * i=ii|3ri tii ill i.U Sll 9 M M B 8 M 3 Me MbMa =22 mm 1 5isS B a I M 3 1 8? I a <3 JiSt s 5* 1S Ie 3 M a M m 0 a 3 Jl 15 4 to3 % lM e1 3 *sX is 41 A 14. i i i ! i ij 1 I > I i ii The relative degree the four asbestos fabric VI. This summary of t plants has been prepare TABLE VI. RELATIVE Drp*rta*t trtpmtloa tad CutUn* W*Ttoc aatf Bate Spinier ~ TwOtuoUkMo*,. Wteto. dtof,---R-ap* 4- 1 ' * It trill be seen that t preparing room, where ment. The lowest com ring gaskets. The figt: relative dustiness, do n partment. The concern of the process varies, d method of manufacture necessary to discuss sei era! operations. The fL resent the concentration foot of air. Preparation--The dtt: due to pure asbestos, r gree of dustiness depone it was found in plant ft LoweU opener, the aver centration of 33.2 whci in exactly the same wr In plant D one of the length mill fiber withe opener. The employe screen was iouud to he ond workman, whose fit fiber after it had been r> posed to a concentrator In the mixing room, the degree of (lustiness the type of fiber used. 10.6 when a mixture of mixing picker. The eon i 11 i i i- i The relative degree of dustiness in the various departments of the four asbestos fabricating plants surveyed is indicated in Tabic I VI* This summary of the average concentrations from the different plants has been prepared from the data contained in Table V. I . CABLSVt. azumvis doAsStBEcSoTjOccSes1'tLrAa.NtTtSons tx DKPAHTiir..vrs or i Dnmtuml SSaoomatpbkeir paCnotnecteetnptreartiConu--MeMFilloioont*oof Af ir MfpilBOT Xaxlmtua Average \ PwssfUas tad Carding , ' ............. * M 123.3 . 44M Waning tad Holt Spinning...............----! *1 i TOiMaltnmt., W*i.ndin--g, , Boat ta, d....W...ic.k. Braiding. ! 1 *9 !. 74.2 ` 1M? U 4.M It trill be seen that the highest dust concentration occurs in the preparing room, where the asbestos receives its preliminary treat ment. The lowest 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 partment. The concentration of the dust in the successive phases of the process varies, depending on the type of fiber used and the method of manufacture. In order to cxpfaiu these variations, it is necessary to discuss separately, conditions encountered in the sev eral operations* The figures given in the following paragraphs rep resent the concentration of dust in millions of particles per cubic foot of air. Preparation--The dust in the preparing rooms is practically all due to pure asbestos, no cotton having been anaetL The de cree ot dustiness depends primarily on tne type of fiber used. Thus, it was found in plant B that when mill fiber was fed into the SacoLowell opener, the average count was 119.4, as compared to a con 1 centration of 33.2 when the longer-staple crude fiber was treated l in exactly the same way. In plant D one of the operations involved the screening of shortlength mill fiber without first passing it through a Saco-Loweil opener. The employe engaged in feeding the material onto the screen was found to be exposed to a concentration of 65.7. A sec i 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 i the type of fiber used. For example, the concentration of dust was 1(X6 when a mixture of cotton and mill fiber was being ted into the mixing picker. The concentration dropped to 3.1 when the mixture 15 I y ) i 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--The 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, 24J, 29.S. 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-back, 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 approxi mately one-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 remainderof 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-card, which is a brush covered with strips of card cloth. The cylinders are slowly turned by hand at the same time. The dust concentra tion during this operation was 5.5. Sometimes the roils are cleaned while they are being turned at the customary carding speed. The employes stated that this was a very dust}* operation, but it was impossible to obtain samples during this procedure. Weaving--The concentration of dust in wearing is dependent on many factors, but prindpallv 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 in sulating tape and brake lining in plant C A concentration of was associated with the weaving of tape (made from crude fiber). In the wearing 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 wearing process (page 8), wearing may be done either with the yam dry or moistened with water. The presence of moisture materially* decreases the con centration 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 wearing of cloth in plant D. In this plant, ordinary electric fans were located just back of the weavers, so that dust generated in the process would he blown away from the worker's breathing zone. When the fans were operating the concentration of dust in dry wearing of cloth forty inches wide was 92. When the fan* were turned off, the figure rose to 33.3. The fourth factor,^ nature of the finished product, also influences the degree- of dustiness. Thus, the average concentration en- 18 . ti !iiI i | i \ f i I i \ countered in weaving ; and of brake lining, 23. The looms in time a moved pcriodicaliv (gc with a flexible rtii>l>or > the time required During this operatiou t Spinning--'The couce depends on the type o yam. A count of 2.1 from crude fiber for th. from a high grade of mi dost associated with t: cheapest grade made, \ the mule spinning in pi to which the mule spi: all operations from pn same room. Conscquc centration is due to nu Other Operations--T the production of asbc; tions of dust associate' plant A this was found ascribed to winding bt performed in the same figure of 2.4 was found figure increased to 4.0 Warping is a media spools or warp beams dust, the concentration Dust Coxc In addition to the f plants manufactured ot! was considerably less products included 35% asbestos cements, shin; bestos paper which con fiber. Determinations some of these operatio Or This survey was coin tos dust, but other inn hazards were found. T gasket and molded brat room, and lead compo the finishing asbestos I are lacquer solvents an erations. * & i An the lowest grade *v>|ai847. 'Zti'J.Jdvst count in the grades of asbestos ;|re is being carded concentration of K;:: ft of yam, such as made from mill : i-4U liber was being ` J^les were collected , jritori, as it emerges jjnel-back, becomes ?; go to the rear of ^requiring approxitone plant that the S during this time, ^exposed to a eon* l card and clean or ( with a hand-card. Ith. The cylinders .he dust concentra te roils are cleaned girding speed. The ^ration, but it was fure. pg is dependent on r (1) quality of the ?5 done dry or wet; Fie finished product, ithe weaving of infoncentration of &9 r from crude fiber). * ber. the count was >!ry and the fill wet. jg process (page 3), f or moistened with decreases the con\l weaving of brake pven dry the count ;ng of cloth in plant Seated just back of *ss would be blown 4ten the fans were |vmg of cloth forty ^ned off, the figure - iict. also influences I concentration en- 1 countered in weaving insulating tape was 10.5; that of cloth, 2] .3; ; and of brake lining, 23.0 The looms in time accumulate a great deal of lint. This is re moved periodically (generally once a week) by beating the loom : with a flexible rubber paddle. Each weaver cleans Ins own loom, the time required being approximately one-half hour per week. During this operation the dust concentration was 74.1. Spinning--The concentration of dust in the mule spinning room depends on the type of asbestos fiber used in the making of the I yarn. A count o*f 2.1 existed during the spinning of yam made ' from crude fiber for the weaving of insulating tape. A yarn made ' from a high grade of mill fiber produced a concentration of 5.5. The 1 dust associated with the spinning of commercial grade yam, the cheapest grade made, was tound to be 132. These figures are for the mule spinning in plant B. In plant A the average concentration to which the mule spinners were exposed was 23.0. In this plant all operations from preparing to weaving were carried on in the same room. Consequently, it is impossible to state that this con centration is due to mule spinning alone. Other Operations--Tlie minor mechanical operations necessary in the production of asbestos textiles have relatively small concentra. tions of dust associated with them. In the winding operation in plant A this was found to be 8.0. Again, this number cannot all be ascribed to winding because of the fact that all operations were . performed in the same room. In plant B. in the twisting room, a , figure of 2.4 was found associated with twisting two-ply yam. This figure increased to 4.0 when yam was twisted three-ply. Warping is a mechanical transfer of the twisted yam to large spools or warp beams for the looms. It gives rise to very little ' dust, the concentration being 1.0. Dust Concentrations is Otxxe* Processes ' In addition to the fabrication of asbestos textiles, one of the plants manufactured other produets in which the amount of asbestos was considerably less than the amount used in textiles. These products ineluded 85% magnesia insulation, molded brake lining, i asbestos cements, shingles, lumber, and tile. One plant made as ! bestos paper which contains ninety-five per cent of short-staple mill j fiber. Determinations of the dust concentrations were made at . some of these operations. The results are shown in Tabic VII. ' Other Potential Hazards This survey was concerned only with the hazard caused by asbes- tot dust, but other materials that must be considered as potential _ hazards were found. These materials are gasoline and benzol in the ' ' gasket and molded brake lining departments, talc dust in the gasket room, and lead compounds in the ntbber mixing department. In , . the finishing asbestos lumber and tile, additional potential hazards ; are lacquer solvents and sand from the grinding and polishing op erations. .. IT t \. j .* TABLE YU. OCST COXCZSTRATtOSP OP 3U5CZLLAXEOCS OPKRATtOXS IH AX ASBESTOS PL4XT DOUtwal OptfttM Coaw i trattoe to Bomb*; UUHoosot Of ; partteM per eabta I foot of Air Ptprr UO B* pbat Uuba<mcwiMt*wta) QBfatfdbs* CnidUas scbcrta* (tom fiber) Batfita* utwlw (TUB fiber) fatiof "air riT ptpa tornipf Siar obcitaa lumber Similar wbeotoo fcunber ual tllo ODraonotreta*ctob*atihpraoiosmt rptflnep booth) rater barrrti wftb mcoecte Pbovrltec macoerte or plto TtoMptar barer* into steer Oratea* pipe tnaklt Peeiitar tecutettoo toco ttumoet _ Beworiac tacolattaa from tetamer Cxntbta* tad b*gtt* temp ...... -OSitUadaltao*art*tbrri--tolwi pfaper ^mmm--mm. etatefi tedap Dvfillar paper date* factac* > ta.4-1U.fi 00.4 34.4 190.fi tfi.-94 fikl-SS.fi fit.? mS40t0T.0 filP.fi 10.9-1004 14 0.4-14.1 94.040.0 44 4U.4-US.T ll.fi ASBESTOSIS--PART Encountered in Asb< of Complete physical exn (48 men, 16 women) en Part II of this report. ( exposure were used as < sm'ctcd to those emplo; longest employed were a sufficient number fron paid to the group with particular operation at VIII shows their age <1: TABLE YTU. DISTXI I Sami Asbestosis was foun< or 25 per cent of the oxj as negative and the ren one individual had prev been the primary or cc eliminated from any fv. bestosis were divided i monary fibrosis, no ad\ mation of the degree c extent of fibrosis seen ings. The present, past, at: histories were secured might influence the inc. symptoms, were avoi<l< dominating subjective and dyspnea. Other i: and frequent colds. Oi symptoms. 18 i forounoxs in an C0WU| , tratfe* 0 tatter i UQUetnoi , at ! p*rti*k* twites! per cute* foot ot Air ti. $=) aJbw* UP.4 sa.4 130.1 19.4-9.3 S.HU 34.1 921.4 3MB.0 29.2 JO 1.9 4.4-13.1 SS.MO.t M 434.4-412.7 tLt t i t ASBESTOSIS--PART III.--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-four persons (48 men, 16 women) employed at the time in the plants listed in Part II of tin's report. Of this number seven men without previous \ exposure were used as controls. Selection of the workers was re stricted to those employed in textile manufacture. Those workers I 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 of shorter duration and to the particuiar operation at which the worker was employed. Table VIII shows their age distribution. TABLE Vnt. DISTRIBUTION BT ACE OT ALL PEBSOXS EXAMINES Gtm* 1 taster oil Easawaatf Cater 9 Castrate ......................... ... 1 I taster te At* Groop ii 9-9 j 9-4* j 50-49 .j -i . 1i * 14 . - T 4- 43 IS | 13 u 3 OSaadercr 3 1 t Tteate ,-- 44 I n . 17 4 Asbestosis was found in fourteen persons (12 men, 2 women), or 25 per cent of the exposed group. Forty persons were diagnosed aa negative and the remaining three doubtful. Of the latter group, one individual had previous exposure to silica dust which may have l been the primary or contributing cause and, as a result, has been eliminated from any further consideration. The cases haring as- I bestosis were divided into those having slight and moderate pul monary fibrosis, no advanced cases having been found. The esti mation of the degree of involvment depended on the amount and extent of fibrosis seen roentgcnologicaiiy 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 pre dominating subjective symptoms in the positive group were cough and dvsanea. Other major subjective symptoms were dry throat and frequent colds. One individual in this group had no subjective symptoms. - ' ' 19 V. r ''W `Tfvx*rim*eii- I I Objectively, the major symptoms were again cough- and dyspnea. Thirteen persons of those* diagnosed positive for aabestosis com plained of cough, and eight of dyspnea. Other frequently elicited objective symptoms were frequent colds, palpatatiqn, weakness, precordial pain, and pharyngeal dryness. No objective symptoms could be obtained from one individual in the positive group. Occurrence of acute respirator.* infections was particularly ob served in the past medical history. Frequent coryza or other upper air-passage infections which did not result in a loss of time of three or more working days, were listed as objective symptoms. Pneu monia 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. Five-minute oral temperatures showed a maximum elevation of 0J*C 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 eases. The external auditory canals did not show evidence of plugging or irritation. Clinical examination of the thorax included inspection, palpation, percussion, and auscultation of the heart and lungs. A tendency to increased anterior-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 eases, 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 th tnm in the detection Pf thickened pleura. The htla. trunk, and lung markings of me norotjc lungs were'increased in prominence. In 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 s 4 4 film suggested atclcctasi emphysema, occurred ii> hesions were noted in a domes of the diaphragir of the negative exposed and two of the negativ evidence of healed tuhi disease in four of the po* The occurrence of asl losis were determined in each person. Each empl obtaining the sjmtum > morning sample. An c each sample. After con was centrifuged for thr. and the supernatant liqu the solid centrifuged three minutes. A drop scope slide and examine both 3 mm. and 4 mm. < The greater percental, color, but a few were n: pale yellowish brown e* The largest asbestos bo The bodies occurred si present singly or in dm or a dumbbell shape. \ strand at a position mid\ micrograph of a single a of two or three asbestos :-|>ugh and dyspnea. / r asbestosis com* frequently elicited tatjon. weakness. Jijcctive symptoms 'Itive group. particularly ob* \zz or other upper ' oi time oi three symptoms. Pneu;'|d in three of the ;f past medical his* 4aek of pleurisy in | negative. us contacts were inological evidence tries. Two others who did not have Workers stripped to latest weight were diagnosed as nega-f.peraturcs showed ting asbestosis had ?tive group showed ?group was absent, si the entire group | not appear to be 1. sinuses was not j>d diseased tonsils pry canals did not i C-pection, palpation, fts. A tendency to fest in the positive bp the respiratory h eases. Crepitant, red in nine of the feminant. f t problem. When jiie. with variations bis in the positive y workers, included ^sterior and oblique j'fis chest pathology, in centimeters durf obliqne exposures |ns and particularly trunk, and lung prominence. In toward beading' ' of the lung in one i Ii \ ii i f f i i f i `i i I ; I i film suggested atelectasis. Increased aeration, such as one sees in emphysema, occurred in a. few cases. Thickened pleura and ad* hesions were noted in a few cases. The average movement ot the domes of the diaphragm of the positive group was less than that of the negative exposed or control groups. Three of the positive and two of the negative group were found with roentgenological evidence of healed tuberculosis. Further evidence of pulmonary disease in four of the positive group was clubbing of the lingers. The occurrence of asbestos bodies and the presence of B. tubercu losis were determined in a single specimen of sputum obtained from each person. Each employe was instructed in the proper method of obtaining the sputum specimen, and was requested to collect a morning sample. An equal volume of antiformin was added to eaeh sample. After complete digestion of the mucus, the mixture was centrifuged for three minutes at approximately 2000 r: p. in. and the supernatant liquid decanted. Distilled water was added to the solid eentrifuged portion, and the mixture rccentrifugcd for three minutes. A drop of the deposit was transferred to a micro scope slide and examined for the presence of asbestos bodies under both 8 mm. and 4 mm. objectives. ASBESTOS BODY. MAGNIFICATION 600 DIAMETERS The greater percentage of sputum specimens were of a whitish color, but a few were muco-purulent. The asbestos bodies were a pale yellowish brown color and varied in size, shape, and number. The largest asbestos body found measured 117 microns in length. The bodies occurred singly, clumped, and as fragments. When present singly or in clumps, they presented a bead-like appearance or a dumb-bell shape, with bulbous ends tapering into a narrow strand at a position midway between the ends. Figure 3 is a photo micrograph of a single asbestos body. In one specimen an average of two or three asbestos bodies or fragments of bodies were seen in 21 v-ffr], Voltag? 4 ram. I L 192Z. .^Laborer sled work*, 'jjonm asbestos mill, 15 o --wj. ... . m___{n_fj:iBumium:aun:irnaiHf.'i3f tsiwmaa .... f$j3nTnSrMsSviSh**u?tHn.*tt?t*nfjltMi Sr sasiiini::iatti;H:!vRi WNG OP CASK fir. Height 59 inches. ^ dubbing of fingers. ; normal shape; per* feats; root resonance ippamu enlargement; $nd two minutes alter function*! exercise test, 76, 118, 76. Respiration rate before and two min* otes after functional exercise test, 14, 18. Blond pressore 154/90. Fhaoroseopj^Dtaphraematic excursion; right dome, U cm.; left dome. cm. XpRay^--The limeade cage is negative. The trachea is in the mid-lme. The cardiac rifiwnctte is within normal limits. Tim domes of the diaphragm are regular. The hila and trunk markings are increased in prominence The lung markings are also increased in prominence. Electrocardiogram Cardiac rate 60. P*R interval 0.16 second. Voltage i5 turn. Low voltage of all Q-R-S complexes. Diagnosis -Asbestosi*, moderate. _ TABLE XX. INCIDENCE AST* DKflBEE OF ASKKTOfS WITH BEI-ATJOX TO OCCUPATION, DCST COXCENTHATIOX, AST* TEAKS OF EXrOSCHE 1*1 Omapetloe ftipmn red- Cndm Avtrec* Cowera trattOQ Asbeetoets unuoas o< partte*et Tears per cubic of Xomber t toot gaparerv ExaaUard, Xeiiitve ttlbt Msdente Ailriflud Doebttui 11 M ^4* S t -- - ! ,, * 1 -- --. 44J U--IS $ t 1 ii * ! t1 - --_ ---- evert* l \ 1 >-j - _-- Total u .1 t 1 - 1 M . ! .. . irT- ' SAJI K-W - 4 ! *j l 4 1 ts -- 1 -- _ .. ---- ---- over* * * I- -- ---- Total 1* 14 a 1 -- munis. TUMcn. Warpers, eta. TMaia 04 s-to 4A4 U--IS M-SB ever St Total 4 7 St IS 4 }*1 1 1 * I | a* #7 -- -- -- - '1 -- -- -- -- - - -- 1 -- -- t 1 The principal factors now thought to determine incidence and degree of the pncumonoconioscs are nature and concentration of the dust, length of exposure, and individual susceptibility. The in* 27 i ----- ' ' ''> - - ....................." - '-< - n * ........ .... ........ " ' ' ll ddence of asbestosis with relation to occupation, concentration of the dust, and length of exposure in the fifty-six 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. 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. SuuiXAsy (I). The concentration of dust in asbestos fabricating plants de pends primarily on the grade of asbestos; mill fiber gives rise to a higher concentration than crude fiber. Operations arranged in de creasing concentration of dust are preparing, carding, weaving, spin ning, twisting, winding, and warping. ^ (2). The average particle sue of asbestos dust is stated in two diameters, longitudinal and transverse. (3) . Petrographic analyses of dust encountered in asbestos fabri cating plants collected in the workers' breathing zone shows it to contain no free silica. (4) . Fourteen, or 25^ of fifty-six workers employed in the tex tile 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 Depart ment of Labor and Industry the facilities of his department; Dr. C A. Laubaeh, roentgenologist and cardiologist of the Norristown State Hospital, for doing a large majority of the X-ray work, and his technicians for the routine laboratory examinations; Dr. J. D. Heard and Dr. A. B. Fuller of the. University of Pittsburgh, and Dr. C. C Wolferth of the University of Pennsylvania, for their as sistance and interpretation of the cardiograms. * Bibuogiafky . 1. Andante. Hyg. du tray., 1:191-192, 1930. 2. Anderson, H. V., and Clark, G. L.: Application of X-rays in the Classification of Fibrous Silicate Minerals Commoniv Termed Asbestos. Ind. and Eng. Chem., 21:924-933, 1929. 28 3. Auribault: Note? dans les filattm trav., p. 120-131 4. Baader, E. \V.: med. Wclmschr. 5. Beger, P. I.: l Arch., 290 ^S0- ; . 6. Beger, P. I.: Moi r 530-539, 1934. ; 7. Bcgcr, P. I.: Inj Med. Klin., Sep i J. Ind. Hyg., V . 8. Beintkcr, E.: As behyg., 2:345-3. .9. Beintker, E.: Asb 1934. Abstr.,J ia Bowles, Oliver: U. S. Bur. Mim . Tl. Bridge, J. C: As of Fact, for th< don, 1929. .12 Bromley, J. F., W --A Discussion Asbestosis. P Radiol., p. 262 1934. 13. Buttner-Wobst, V (asbestosis) u: muss. Tuberkt 14. Grkel, Fritz: Chi tion. Milling ai Dep't of Mines, ? IS. Gynes: Asbestos t : 16. Cooke. W. E.: I Asbestos Dust. 17. Cooke, W. E.: A 18. Cooke. W. E.: P 1928. ; 19. Cooke, W. E.: A Pulmonary As Abstr., T. Am. Hyg., 12:34, 19 . 20. Cooke, W. E.; . Lungs of Asbi <i 1931. Vt, concentration of Arsons examined in |lhe examination of non of definite con- is it possible from Jfentration of asbes'.|investiffarion show r^ntrarions in those |therc*is continuous ! >ii i 3. Auribault: Notes sur ITiygiene ct la securitc dcs ouvriers dans les filatures et tissages d'amiante. Bull, de l'lnsp. du trav,, p. 120-132, 1906. 4. Baader, E. W.: Asbestose mit Warzenbildung. Munchcn med. Wchnschr., 79:83, 1932. 5. Beger, P. I.; Ucbcr die Asbestosis Korperchcn. Virch. Ardu, 290*230353, 1933. . 6. Begcr, P. I.; More on Asbestosis Bodies. Virch. Arch., 293: 530-539, 1934. Abstr., J. Ind. Hyg., 1722, 1935. ' iricating plants defbev gives rise to a Jis arranged in de ling, weaving, spin ' 7. Begcr, P. I.: Injurious Factors in Asbestosis and Silicosis. . . Med. Klin., Sept. 14, 1934, p. 125S-1261; 1922-1927. Abstr., J. Ind. Hyg,, 1722, 1935. 8. Beintker, E.: Asbestosis. Arch, f. Gcwerbepath. u. Gewer- bchyg., 2245-358, 1931. * et is stated in two 9. Beintker, E.: Asbestosis Bodies. Virch. Arch., 293 : 527-529, * 1934. Abstr., J. Ind. Hyg., 1723, 1935. ? ri in asbestos fabri: zone shows it to tiployed in the tex : Pennsylvania had : >estosis. ^Commonwealth of and employes of ? crest which made :*oast and Dr. E. P. : whose interpreta of the University and advice in the : Secretary of the ?ag to the Depart department; Dr. of the Norristown * X-ray work, and nations; Dr. J. 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Cooke, \V. 2L, and HH1, CF.: Further Observations on Pul* monary Asbestosis. with Special Reference to Asbestos Dust and Curious Bodies found in the Lungs. J. Roy. Micr. Soc, 50:15-19. 193a 26. Davis, G. Gy Salmonsen. E. M.. Earlvwine, J. L.: The Pneutnonokonioses (Silicosis). Bibliography and Laws. Ind. Medicine Inc, Chicago* 1934. 27. Dewirtz, A. P.: Warts from Mineral Substances. Roussky Vestmck Derm. 1243-247, March, 193a Abstr- J. Ind. Hyg, 13:125, 1931. . 28. Dhers, V.: Amiante et asbestose pulmonaire. La med. du trav,, 2:147-172; 187-209. 193a Abstr., J. Ind. Hyg., 13:49, 1931. . 29. Donneily, J.: Pulmonary Asbestosis. Am.' J. Pub. Health. 23:1275-1281, 193a 3a Drinker, P.: Alternating Current Precipitators for Sanitary Air Analysis. J. Ind. Hyg,, 14264-370, 1932. 31. Drinker, P.: The Sire Frequency and Identification of Cer tain Phagocytosed Dusts. J. Ind. Hrg,, 7205-316, 1925. 32. Effect of Asbestos Dust on Workers* Health in Asbestos Mines and Factories. Labour Gaz^ 12:761-762, 1911-1912, Ottawa. 33. Ellman, P.: Report on Cases of FuJmonarv Asbestosis. Proc. Roy. Soc. MetL, 24226, 541, 699, 1930-i93L 34* Ellman, P<: Chest Diseases in General Practice. London, H. K. Lewis, 1932, p. 11& 35. Ellman, P.: Pulmonary Asbestosis. Lancet, Feb. 4, 1933, p. 252-253. Abstr,, J. lad. Hyr- 15:43, 1933. 36. Ellman, P.: Pulmonary Asbestosis: Clinical. Radiological and Pathological Features and Associated Risk of Tuber culosis Infection. J. Ind. Hyg,, 15:165-183, 1933. 37. Fahr, T.: Asbcst-pneumokoniose. AertzL Verein. March 3, 1914. Hamburg. 38. Fahr, T.; Asbestosis. Klin. Wchnschr., 11:1114, 1932. 39. Feii. A.: Asbestosis in Asbestos Workers: Professional As bestosis. Presse MetL, 39:1931,1872-1874. 30 40. Fcuerstack: Ucb veolcn bci dcr schrift, 18S2. 41. Fulton, W. B,, t Asbestosis. P: bestos Dust, i try, 1934. 4Z Gardner, L. U., a mental Pncuct Dust; Its Etf- J. Ind. Hyg., 1 43. Gerbis, H., and L L inn. Med. z. 44. Gerbis, H., and T med. Wchasci 45. German Work ot 1932. 46. Gloyne, S. R.: I Asbestos Work 47. Gloyne, S. R.: F Reference to P 193a 48. Gloyne, S. R.: M in Sputum of . 1931. 49. 5a 51. 52. v 53. 54. 55. 56. 57. Gloyne, S. R.: ! 12299-401, 19.'- Gimme, S. R.: ICase of Pulmov Gloyne, S. R.: A Gloyne, S. R.: Lung. Tubercl Gloyne, S. R.: MTubercle, 14:45 Hyg., 15:127-12 Gordon, B., Jr.: 639, 1932. Green, Henry: A tion of Particit Franklin Inst., Green, H. L.: So Number and Si: Hyg,, 1629-39, Haddow, A. C: ( Brit. Med. J., 2 >8> Curious Bodi*es , |d. J, 1 .-656^*57, 40. Fenerstaek: Ueber das Vcrhaltcn des Epithets dcr Lungcnalyeolen bei dcr fibrindscn Pneumonia. Gottingen, PreissschrifL 1882. .stasis due to As* ^ |927. :':",;>'S'osts Caused by I Strange Bodies ^Sf36-137f 1926. - 'C.-^irvations on PulC'^ . 'ince to Asbestos ILungs. J. Roy. t I 41. Fulton, W. Bn Houtz, R. L, Dooley, A., Matthews, J. L.: Asbestosis. Part I--The Collection and Counting of As bestos Dust. Spec. Bull. 37, Pa. Dept. Labor and Indus try, 1934. 42. Gardner, L. XL, and Cummings, D. E.: Studies on Experi mental Pneumokoniosis: VI. Inhalation of Asbestos Dust; Its Effect upon Primary Tuberculosis Infection. J. Ind. Hyg, 13.-65-81, 97-114, 1*931. 43. Gerbis, H., and Ucko: Ueber Asbestosis dcr Lungen. Ver. I Inn. Med. z. Berlin, Sitz. v. Dec. 7, 1931. f. L.The Pneuand Laws. Ind. hanees. Roussky j. Abstr, J- Ind. fire. La med. du l Ind. Hyg, 13:49, L J. Pub. Health. }.tors for Sanitary 5932. Utificatkm of Cer'7-JOS-316, 1925. *lth in Asbestos iVSl-762* 1911-1912, / Asbestosis. Proc. }#U ' practice. London, feet. Feb. 4, 1933, `i933. jucal, Radiological j?d Risk of TuberJS3, 1933. j Vereiu. March 3. |l :!U4, 1932. j| Professional As-. 44. Gerbis, H, and Ucko: Asbestosis of the Lung. Deutsche med. Wchnschr., 58-285, 1932. < J 45. German Work on Pulmouary Asbestosis. Lancet, 3 92-93, 1932. * 46. Gloyne, S. R.t Presence of Asbestosis Fiber in Lesions of i Asbestos Workers. Tubercle, 10:404-407, 1929. 47. Gimme, S. R.: Reaction of Tissues to Asbestos Fiber^ with reference to Pulmonary Asbestosis. Tubercle, 11:15i-153, . 193a i 48. Gloyne, S. R.: 'Method of Staining Asbestosis Bodies Found in Sputum of Asbestos Workers. J. Ind. Hyg., 13:S5-86, 193L 49. Gloyne, S. R.: Formation of Asbestosis Bodies. Tubercle. 12:399-401, 1931. 5G Gimme, S. R.; Presence of Asbestosis Bodies in Faeces of Case of Pulmonary Asbestosis. Tubercle, 12:158-161, 1931. 51. Gloyne, S. R.: Asbestosis Body. Lancet, 1:1351-1355, 1932. > 52. Qoyne, S. R.: Infra-red Photomicrographs of Asbestosis l Lang. Tubercle, 14:203-209, 1933. 53. Gloyne, SR.: Morbid Anatomy and Histology of Asbestosis. Tubercle, 14:455-461, 493-497, 550-558, 1933. Abstr,, J. Ind. 4 Hyg,, 15:127-128, 1933. 54. Gordon, B,, Jr.: Asbestosis. Pennsylvania Med. J,, 35:637 i 639,1932. 55. Green, Henry: A Photographic Method for the Detcrmination of Particle Size of Paint and Rubber Pigments. J. i Franklin Inst, 192.-637-666, 1921. I 56. Green, H. L: Some Accurate Methods of Determining the Number and Size Frequency of Particles in Dusts. J. Ind. Hyg, 16:29-39, 1934. i 57. Haddow, A. C: Clinical Aspects of Pulmonary Asbestosis. i Brit. Med. J, 2*580-581, 19&9. 31 58. Hatch, T., Warren, II., Drinker, P.: Modified Form of the Greenburg-Smith Iinpiugcr tor Field Use, with a Study of its Operating Characteristics. J. ImL Hyg., 14:301-3il, . ' 1932. 74. Merewether, E. K Asbestos Dust Asbestos Imlu: 1930. Abstr., \ 59. Hatch, T. and Pool. C. L.I Quantitation of Impinger Dust Samples by Dark Field Microscopy. J. Ind. Hyg., 16:177 191,1934, 60. Holtzmann, F.: Die Eimvirkung des Asbeststaubes. ZentraibL L Gewerbehyg., S 25-226, 1931. 61. Industrial Directory--1931 Edition. Pa. Dep't of Internal Affairs, Harrisburg. 62. Katz and Slater: The Second*. Positive Wave of the Q-R-S Complex. Arch. Int MetL, 55: No. I, Jan. 1935. I 63. Kettle, E. H.: Interstitial Reactions Caused by Various Dusts h and their Influence on Tuberculous Infections. 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