Document reYm3Y2DkQD57BeZ5n2j8G067

FILE NAME: General Motors (GM) DATE: 1939 DOC#: GM067 DOCUMENT DESCRIPTION: Internal Report - Air Hygiene Studies - Inland Manufacturing Division AIR HGIENE STUDIES Inland Manufacturing Division Dayton, Ohio October 31 and November 1, 1939 By: L.5. Case Seven tests pertaining to asbestos dust, five tests pertaining to both asbestos dost and lead, and sundry observations were made in cooperation with Messrs. U- L. Soier, A. H. Flower, E. Goraar., K. J. Joyce, E. D. Croy, H. Dreher, D. H. ?hiilipi, M. E. Gordon, S.S. Connair, H.V. Kelly, J. Zinecrii, T.K. Jones, I. Schunate and Dr. R.D. Johnston. Th- exposures under consideration are incidental to the production of brake ii ir.gs and clutch facings. The brake linings and extruded clutch facings con ta. n asbestos, rubber, and other ingredients but no lead or lead compounds. The wo en clutch facings contain asbestos, f a . S S wire, rubber and other ingredients, it. luting litharge or its reaction products. The finished material contains lead ct pounds corresponding to approximately 13% of lead. Conclusions and Suggestions (} The gasoline vapors in the cement department appear to merit further attention (p. 2). (bi It appears desirable for the operator in the cement department to use an approved respirator while emptying litharge into the mixer, and that accumulations cf oust should be removes periodically from the horioontel surfaces in the vicinity by a vacuum cleaner {p. 3). (c) The situation in the laboratory probably is not serious but might merit the precaution of using a respirator and a vacuum cleaner (p. 3). (d! The dust near the unwinding operation in the cement house approaches, or exceeds, the permissible limit and the use of a respirator is suggested (Test il). (e) The lead concentration found near the machine grinding clutch facings to thickness is unexpectedly high, and the location is recommended for further observation (Test r5). !f} The lead concentration near the groove cleaning operation exceeded the permissible limit, and the installation of an exhausted table grating is suggested. tgl Both the dust and the lead near the "flap sanding" operation greatly exceed the permissible limits and changes in method or ventilation are needed (Test $7). (hi Substitution cf vacuum, cleaners for air jet for removing debris from a drill press table is suggested. (Test * ______ i (i) The slitting machine emits an ______ _ asbestos dust in spite of the fact chat the volume of air ___________probably inadequate. Changes ere suggested (Test # :ue:.e S: res Page #2 Inland Mfg. Division (j) The continued us 5 of respirators by the men weighing the ingredients ci the brake lining compound appears to be desirable. The use of respirators during the brief period when the mixer is discharged also is indicated (Test #12}. Asbestos The literature relating to occupational diseases contains many references to the effects of inhaling excessive amounts of asbestos. Public Health Bulletin #241, "A Study cf Asbestcsis in the Asbestos Textile Industry"; International Labour Office, supplement to Occupation and Health, dated January 1938 and entitled ;bestos"; Public Health Reports, November 26, 1939, "A Study of Dust Control .Me :hcds in Air Asbestos Fabricating Plant," and Sayers & Dreesen, American J-: rrr.sl of Public Health, March, 1929, "Asbestcsis", may be mentioned prominently i: this connection. Kavhurst, in Industrial Medicine, October 1939, quotes George a: : Leonard in discussing 90 claims, ascribed to asbestcsis, brought against a item formerly manufacturing brake linings in Massachusetts. Twelve positive diagnoses were rr.ade, and the insurance carrier arranged compensation or settle ment ir. excess cf 330,000 for the twelve. Thirty of the re~.air.ing seventy-eight came to trial. There appears to be some difference cf opinion regarding the diagnoses, especially in view of the re-examinations, cf the twelve awarded compensation, made some eight or nine years after the cessation of the exposure. As is common in those complicated affairs, there may be some difference of cginior. regarding the permissible limit for asbestos dust. It appears proper, however, to accept the findings cf Sayers a Dreesen (American Journal of Public Health, March 1529, p. 2C5-214), which indicate a permissible limit of 5,000,000 particles per cubic foot cf air. They state:- "Definite clinical and roentge.nocraphic evidence cf asbestcsis is observed in exposed persons after 8 to 10 years cf work in exposures exceeding 5 million particles per cubic foot of air," ar.d "It appears that, if asbestos dust concentrations in the air breathed are kept c low 5 m.p.p.c.f., new cases cf asbestosis will not appear." Further, it may b prudent to disregard suggested distinctions between long fibres, short fibres, and particles too short to be classified as fibres. .-..out ten years ago, the Public Health Service conducted an investigation in a large storage battery plant and cautiously suggested 1.5 milligrams per 1C cubic meters of air as the permissible limit to lead. A recent survey, involving air tests- in 26 plants and the medical examination of approximately 700 men, is interpreted to confirm the previous conclusion and to indicate that the limit of 1.5 mg is required to avoid "early plumbism". Discussion of the matter has suggested that "early plumbism" may not be very serious. Nevertheless, it appears prudent for lead concentrations to be maintained below that limit so far as possible. Gasoline Vapor As compared to chlorinated solvents and coal-tar hydrocarbons, it appears that gasoline vapors are relatively non-toxic. They are not, however, without physio logical effect. A committee, acting in behalf of the Massachusetts Division cf Occupational Hygiene, has suggested that the 1000 parts of vapor per million parts cf -r s a proper "limit for practical control". This is equivalent to 0.15; by relume- The ____ flarimatie limit for gasoline vapor is approximately 1.41 by .-.ir Hygiene Studies Page #3 Inland Hfc. Division volume fiursau of tiir.es bulletin *2"?) . Hr. Gordon stated that tests with an explosineter have shown concentrations in excess of the allowable limit in certain locations at certain times in the cement department. He further stated that con centrations approximating 205 cf the explosive limit are quite common. The gas oline used is more volatile than the grades generally employed for automobile fuel. The men in the room complained when the doors and windows were closed, to simulate winter conditions, for about 15 minutes in Test #1. Dr. Flower stated that the matter could be given further attention to locate the principal sources of the vapors (there appear to be several) and to investigate the possibility cf using a less volatile solvent. Miscellaneous Items S v e r a i additional situations were observed and discussed. T. i air exhausted from the finishing operations on brake linings and clutch i - :ings is passed through cyclone separators on the roof. As is common with c\ lor.es, much of the finer material escapes. At times the fine dust is blown b. k into the factory via the windows in the monitor. Messrs. Conr.air and G don stated that the accumulation in the bin under the larger cyclone is re- m. -ec ar.t bagged three times per day.At times the cust from thebagging ct ration may enter the monitor windows. The accumulation in the bin has a c- vcency to catch fire and smolder. A fire hose is kept unreeledand in reac- L : -zs at ail times. The material doesnot wet readily, and it is difficult to extinguish the fires. Mr. Conr.air stated that the cyclones may be replaced by or American Filter wet systems. Presumably the venders of the equip ment will be duly warned cf the fact that the dust does not wet very readily. lead is one cf the ingredients in the cement used in the clutch facings. Hr. Pr.iilict stated that three times each day a 50# bag is emptied into a mixer, because of the brevity and infrequency cf the operation, no test cf the air was -ace.' A sample cf dust from an angle iron supporting the stairway contained 1C.7% cf lead. Certain experimental compositions are finished in the laboratory. The operation cs infrequent, and the alcove in which it is conducted is isolated, during the c -.ration, from the remainder of the laboratory by a curtain. No specimens were a :liable for grinding or, November 1st and no test of the air was mads. However, a .ample of dust from the lamp shade contained 5.6% lead. Mr Schemata inquired about wood flour. He stated that it is used in seme of the c- pounds, that the batches are mixed frequently, and that the men appear to ii'./.sle some o: the dust. Ke are not well informed about t'ne effects of inhaling wood dust. Woodworking has been a major industry, and power tools have been used for many years. It appears, however, that the matter has not been investigated thoroughly. Dr. Adelaide Ross Smith (Industrial Hygiene, New York Department of Labor, July and August 1936) has received the literature bearing on the subject, and notes 14 references. The review indicates that _____ workers have been above the average in susceptibility to bronchitis, pneumonia, tuberculosis, and perhaps other respiratory diseases. The _____ of the wood dust as a causative factor is indicated but not proven. Methods of Test The dust end lead samples were collected by means of the Greenburg-Smith impinger apparatus. Normal butyl alcohol was the ___ liquid in one instance. The .-.ir Hygiene Studies r 3 S #4 Inland Kfg. Division counts were made according to the technique described in Public Health Bulletin ='17. Lead was estimated cciorimetrically by a procedure employing diphenylthiocarbarone. leather Both days were d e a r with temperatures varying between approximately 30 and approximately 50F. The windows in the monitors of the factory Were party open. TDST #1. ASESSTOS Cement Department, 10/31/39. 1:19 to 2:43 (corrected for interrup tions >: 20 minutes) The sample was taken in the aisleway between the supports from which asbestos cord is unwound. The cord then passes through tanks containing cement, then through drying towers and eventually is made into clutch facings. Dust escapes vi:gbiy from the cords during the unwinding process. We are informed that c.inertly ten men work in the room, which is quite large. One appeared to so-ns m.ucn of his time in the location sampled, ar.d two ethers were working r. a arby. Immediately prior to the test tne doors and some of the windows were open. At our suggestion, Kr. German arranged to have them closed in order to simulate winter conditions. The far. in the cupola was running, and the louvers in the wall were open. After about 15 minutes, the men at the extruding machine, and the men or. the platform, objected to the gasoline vapor, and the time of the test was shortened. Ft cement was compounded, or. the platform: over the location sampled, during the time covered by the test. The test indicates 1C,COG,000 particles of dust per cubic foot of air. Bven if aiiowar.ee is m.sde for the fact that the operator does r.ct spend all of his time among the cords, ar.c perhaps for the fact that the windows were closed (although tney.no doubt will be closed during- the colder weather), the concentration found approaches, cr probably exceeds, the permissible limit. Because of sire and s. -.ape of the installation, the position of the operator, ar.d the necessity of a;:essibility, it does not appear expedient to install ventilating equipment. Perhaps the operator could be persuaded to use a respirator, at least part of TEST #2, ASBESTOS Cement Department. 10/31/39. 2:48 to 3:18 The sample was taken at the shoulder cf one of the men blending brake lining compound. Three Champion mixers are located near the westerly wall of the room (the same room that was involved in Test 41) and are used to blend the asbestos mixture (see Test #12) with gasoline, rubber, etc. The asbestos (and other dry ingre dients) is received in boxes containing 100#. These are dumped into the Champion mixers. Gasoline (a relative volatile grade) end rubber are added. The mixer is then covered with a wooden cover and permitted to run until the blending has beer, accomplished. About 4 minutes is required oc charge two mixers. The escape Air Hvciene Studies ?age #5 Inland Mic. Division cf dust, when -he boxes ere dumped, is very noticeable but also quite brief because the csscline is added immediately afterward. There is a noticeable escape cf gasoline vapor beer, during and following its addition. The covers co ''v tightly. Three batches were nixed, ana the floor was swept during the tine covered by the test. One cf the two operators wore a respirator while dumping asbestos but not while sweeping. The doors and sorts of the windows were open during the test. The test indicates 2,500,000 particles cf dust per cubic foot of air. TEST #3, ASBESTOS Chamfering ends of brake linings, alcg. 11. Dept. 15 10/31/29. 3:33 to 4:03 The sample was taken at the shoulder of .the operator cf the vertical grinding wheel used for the purpose. The wheel is hooded and connected to a fan. The rate of air-flcw through the opening in the hood varied cron 400 to 500 feet per minute. The normal rate cf production is approxir.stely 640 pieces per hour, and the operator spends about 4 out of hours at this machine. The test indicates 1,500,000 particles cf dust t>er cubic feet cf air. TEST U , ASBESTOS Fir.ishir*c brsks --nine series eo tmcr.ness. Hide. 11. 1c. 10/31/39. 4:03 to 4:22 The sample was taken at the shoulder of a cirl operating the machine which grinds b :th sides of the bra,:e lining strips simultaneously. The machine is enclosed, i.-.z the housing is connected to a ventilating fan. There was no noticeable e. tape of dust. We understand that the machine is in use about three hours in etch shift. T..e slitter (Test #7; is located nearby. It was in operation only two minutes o the time covered by the test, but may have contributed somewhat to the dust coun The strips delivered from the slitter to the grinder are somewhat dusty. The test indicates 5,000,000 particles of dust per cubic foot of air. fl M TEST #5, ASBESTOS and LEAD Finishing clutch facing rings to thickness. Bldg. 11. Dept. 16. 11/1/39. 8:20 to 8:34 - 9:12 to 9:23 The sample was taken at the shoulder of the inspector working at the outlet (westerly) end of the machine. There was a craft of approximately 50 feet per minute from east to west. T.ne machine is similar to the one involved in Test 4. It is enclosed, and the housing is connected to a ventilating fan. There was no visible escape of dust. The machine is in use only part of the time. Air Hygiene Studies Page 6 Inland Kfg. Division Four women and two .tier, ware working in the aislewsy extending about 20 feet west of the r.aonone. The brake lining slitter and the grinder used for the edges of the clutch facings were not ir. use during the time covered by the test. The test indicates 3,000,000 particles of dust per cubic foct and 3.9 milligrams of lead per 10 cubic meters of air. This amount of lead, considered in conjunc tion with the direction of the -draft, suggests that the ventilation of the mach ine may not be adequate. There is a possibility, however, that it may represent dust dislodged from the surface of the facings as they were handled by the ir.sosctor. TEST *e, ASBESTOS and LEAP Cleaning grooves in clutch facings. Eldg. 11. Dept. 16. 11/1/39 8:38 to 9:02 Ti- sample was taker, at the shoulder of the girl cleaning the grooves in clutch fa.ings by means of a file. She was located at the aisleway west of the grinder ir.-olved ir. Test ?5. The grinder, however, was r.et used during this test. The br.xe lining slitter and grinder were net in use. The drill presses across the a i d s were in operation. The operator of one of the grill presses uses an air jet periodically arc may have contributed tc the dust and lead found ir. this test. Ke understand that this is a full time job, three shifts. '.ima.ee 1; The test indicates 4,300,000 particles of dust per cubic foot of air and 1.2 milli rams cf lead per 10 cubic meters of air. This amount of dust approaches the ermissible limit, and the lead exceeds the permissible limit. Perhaps the iling operations could be performed over a small crating set in the top of the able. The grating would be connected to the exhaust fan via suitable duct work. <1 I.*(.!tf) TEST #>, ASBESTOS and LEAD 'Tier sanding" inside and outside edges of clutch facings. Bldg. 11. Dept. 16. 11/1/39 9:26 to 9:46 The sample was taken at the shoulder of the operator of the machine located near the end of the aisleway mentioned in connection with tests #5, #6, and #8. A double ended polishing lathe is equipped with wheels made by attaching strips of emery cloth to a suitable hub. The term "flat sanding" is an apt description of the operation and equipment. The lathe is equipped with the customary sheet metal hoods. The hood over the wheel used for the inside edges had been opened to permit access. The flaps act as centrifugal fans and overwhelm the intended action of the exhaust ducts. The operator's clothing is blown tightly against his body and legs. There is a very noticeable escape of dust. We understand that the machine is in use about five hours per shift. The test indicates 30,000,000 particles of dust per cubic foot and 20.6 milligrams of lead per 10 cubic meters of air. These concentrations are greatly in excess of Hygiene Studies Page #7 Inland Kfc. Division the permissible limits. Perhaps the edges of the facings could be finished in some" other manner. Perhaps a machine with mechanical feed could be enclosed more completely and ventilated adequately. TBS? #S, ASBESTOS and LEAD Drilling clutch facings. Bldg. 11. Dept. 16. 11/1/39. 10:24 to 10:54 The sample was taken at the shoulder of the girl operating a drill press near the easterly enc of the aisleway. A duct terminal is located about 6" from the criii and hae an inward flow of approximately 900 feet per minute. The general draft in the vicinity was about 50 feet per minute east to west. K-. understand that this is a full-time job. air jet is used periodically for removing chips and dust from the table of the mavnine. It may be responsible for much of the contamination found. The test indicates 7,000,000 particles of dust per cubic foot and 2.7 milligrams of lead per 10 cubic meters cf air. Perhaps a vacuum cleaner could be substituted for ohe air -iet. TBS? 3, AS55ST0S Slitting brake lining slabs into strips. Bldg. 11. Dept. 16. 11/1/25. 11:06 to 11:33 The sample was taker: at the left shoulder of the operator of the machine which slits the slabs of brake lining material (29" x 13") into strips (1-3/4 x 13'). Tr.is is accomplished by a gang cf thin grinding wheels mounted on a shaft. The machine is enclosed and connected to an exhaust fan via two terminals. One terminal is located at the outlet of the machine and the other at the inlet. T.-.s inlet is a slot 1-1/2" >: 36". The terminal is located underneath and produces a:, inward flow of approximately 1000 feet per minute through the slot when no s.ab is in place. The slab, however, interferes wizh the flow through the upper c ..rt of the slot, and a very noticeable escape of dust occurs each time a slab gages the wheel. Tv.;, suggestions nay be offered: (a) That the duct work be divided so that part of the ventilation is taken from the upper part of the machine. (b) A soft rubber strip be installed in the upper part of the slot so it fills the space above the slab. During the test there was a draft of approximately 50 feet per minute from east to west. The thickness grinder was in operation during the test but probably did not con tribute importantly to the dustiness in the location. Air Hygiene Studies Inland Mfc. Division are cr.ferr.sc cha z che ms chine generally is used about further under stand tnat operat or s generally aJLso ri:n the (Test ?f3) ana the scW (Test U 01 . This produces ar. averi excess of the permi cci ble limi W The test indi cates *>*> 000,00 par tidies of dust per cubic oer shift. We TEST #10, ASBESTOS Sawing brake lining strips to length. Elds. 11. Dept. 16. 11/1/35. 12:45 to 1:30, minus 15 minute interruption. The sample was taken at the shoulder cf the operator of the machine, which is If.own as a saw. However, the cutting tool actually is a thin abrasive wheel. There war no measurable craft in the vicinity at the time of the test. Th- machine is equipped with exhaust ducts with terminals ir. the table near the sa The thickness grinder (Test ?<) was in use and may have contributed somewhat to the dust found. There was, however, a visible escape of dust or smoke from the saw. The strips, as they leave the grinder, are somewhat dusty. Ke ere informed that the machine is used about 2 hours per shift. The test indicates 6,000,000 particles cf "dust per cubic foot of air. TEST *11. ASBESTOS and LEAD Grinding outer edces of clutch facino discs. Bldg. 11. Dept. 16. 11/1/35 1:30 to 2:00 One end of e double ended stand is used for the purpose. The wheel is enclosed e..d the housing is connected to ar, exhaust fan. T1 e machine is in use only part of the time. There was a draft cf approximately 50 feet per minute east to west. The sample was taken at the operator's shoulder. The test indicates 1,500,000 particles of dust per cubic foot and 0.9 milligrams cf lead per 10 cubic meters of air. TEST #12, ASBESTOS Mixing dry ingredients of brake lining composition. Basement of Office Building. Dept. 11/1/39. 4:00 to 4:26 The asbestos and other dry ingredients ere blended in a in a Fairfield mixer before transportation to the Cement Department (Test r2). H *-t he ingredients are weighed and most of _____ on the floor above the _____. his location is enclosed, and an exhaust fan was being installed in the roof. The Air Hvgiene Studies ace #9 Inland Kf. Division will be admitted th; ouch openings ir. the lower pert of the partition. It ears prudent for the men to continue the use cf respirators after the instai^i ion of the fan. The enclosure and the fan may be expected to prevent the so esd cf dust to other parts cf the building but probably will not constitute SU ficient Drotection f ir the men within the enclosure. Kr. Schemata stated that the Fairfield mixer in the basement handles 2 batches during the first shift and one batch during the second. The contents of the mixer are emptied, via a gated opening in the bottom, into boxes holding 100* each. About 30 minutes is required for discharging each batch. On the occasion cf the test, the supply of regular boxes was inadequate, and about half of the batch was discharged into a steel tote box and transferred tc fibre cartons. This extra handling increased the concentration of dust. r.en w^re discharging the rr.ixer One was using a respirator. The twe work ether and appear to be exposed to the same; concentration of cust. In cirder 100 pounds of mixture into the boxes, it is necessary for the men to fc it with their hands. This br ir.gs their faces into close preximit y wi .as rear, insta_j.ee amove tr.e opening in the mixer, "he terminal is S" 20", and the rate of air flow minute. removes ,ed from The immediate vicinity cf the mixer is used for storage. The nearest men regularly employed ir. the vicinity were about 25 feet away. Industrial trucks pass frecuently throuch the aislewav beside the mixer. -TiS CITS tne test was variale rn rate and direction. The test indicates 22,000,000 particles of dust per cubic foot of air. Because of the intermittent nature cf the exposure, this does not appear to be very serious. It is prudent, cf course, for the men to use respirators. It also is desirable that the dust should not be permitted to accumulate too extensively, especially in the aisleway where it would be disturbed and distributed by the trucks.