Document 4xp9Jd6D3bQBX7zBN2RaNXx1

FILE NAME: General Motors (GM) DATE: 1960 Mar DOC#: GM066 DOCUMENT DESCRIPTION: Internal Report - Inland Manufacturing Division Dayton, OH Inland Manufacturing Division Dayton Ohio March 16 17 and 18 1960 Inland Manufacturing Division Dayton, Ohio March 16, 17 and 18, 1960 r-:x. Trichloroethylene Asbestos Dust Chromic Acid Toluene Diisocyanate (TDI) 6031 Reported bys G. C. Sto e cke r 00044 Industrial Hygiene Inland Manufacturing Division Dayton, Ohio Several items of industrial hygiene interest were investigat ed at Inland Manufacturing Division on March 16, 17 and 18, 1960, at the request of Mr. S. A. Wright. The subjects were discussed with Mr. H. I. Newsome and Dr. R. L. Johnstone in addition to Mr. Wright. Mr. Wright assisted in the survey conducted by G. C. Stoecker of the Indus trial Hygiene Department. SUMMARY. CONCLUSIONS AND SUGGESTIONS Trich^roethjjlene Tests for trichloroethylene vapors were made in Department 8, Building- 20, at the steering Wheel fin ishing operation in vttiich this material is used. The concentrations found'were below the permissible limit. AsbestosDust. Dust counts were made at brake lining operations in Department 16, Building 11. TOie count at the form ing press was equal to the permissible limit. A count taken at the salvage grinding operation exceeded the permissible limit. Suggestions for better dust control and environ mental improvement are contained in Mr. K. E. Robinson's letter of January 25, 1960, to Mr. H. L. Avery, It would be advisable for the employee to wear an approv ed dust respirator vftiile doing salvage grinding. ChromieAeid Tests were taken for chromic acid in Department 91, Building 25, near the rubber mold cleaning tanks. No chromic acid was detected. 00015 Toluene Diisocyanate j m Page 2 Results of tests for TDX in Department 75, Build ing 28, were well below the permissible limit. Air analyses performed by plant chemical laboratory per sonnel would become a better record on the absence of harmful exposures if scheduled periodically rather than occasionally. Monitoring of this type should be considered. DISCUSSION TricklM^oethylene Finishing of steering vfoeels in Department 8, Building 20, includes immersion of the molded wheel into hot trichloroethylene vapors. The eguipment is essentially a vapor degreaser of spe cial design. The tank is cylinder shaped and the Wheel is auto matically immersed and rotated in the vapor phase. Five of these are located in a separate room. Exhaust slots are located in the center of the room-as a unit with three tanks on the west side and two on the east side. After the \taeels are removed from the tanks they are stack ed on spindle dollies. The plastic absorbs trichloroethylene dur ing the process and,vapors are slowly released from the stacked wheels. Certain solids are absorbed from the wheels, requiring re covery of the trichloroethylene by a separate process. The re covery process consists of heating the solvent in a drum by means of a steam coil. The upper part of the drum is fitted with a water cooled condensing coil. A trough fitted around the inside of the drum beneath the coil collects the condensed vapor and the condensate is piped directly to the end tap of a metal storage drum. The recovery process was not observed in full operation but it was stated that the odor of trichloroethylene is not promi nent and has never caused complaints. Results of tests for trichloroethylene vapors under various conditions are recorded below. The concentrations detected are all below the permissible limit. 0004G Page 3 Permissible Limit f a r Trichloroethylene The permissible limit for continuous exposure to trichloro ethylene is 200 parts per million of air by volume (ppm). Results of Tests for Trichloroethylene Test No. Location and Condition Trichloroethylene in ppm______ 1 Near stacked Wheels after removal from degreasers 2 Breathing zone near degreasers on west side of exhaust system 3 Repeat of Test No. 2 While one vftieel is being removed from degreaser. Maximum detected 95-120 30-50 115 4 Repeat of Test No. 2 with two spin dies of finished wheels located a- long west wall. Exhaust draws vapors toward sampling point 20-50 5 Breathing zone near degreasers on east side of exhaust system 15 6 Repeat of Test No. 5 while one vftieel is being removed from degreaser 50 Asbestos Dust Brake lining manufacturing operations are done in Department 16 of Building 11, The dry material (asbestos, fillers and bind ers) is mixed at another location and transported to Department 16 where the liners are formed, baked, cut and ground to dimen sion. Local exhaust at the cutters and grinders appeared to ade quately control the dust at these operations. However, there is no local exhaust at the forming operation. This requires handl ing of the dry mix and the area is heavily coated with settled dust. 0004 4 Page 4 Asbestos Dust (Cont'd) The brake lining operations were observed by Mr. K. E. Robinson of the Industrial Hygiene Department on January 13, 1960. Specific recommendations for local ventilation and environmental improvement are contained in his letter of January 25, 1960, to Mr. H. L. Avery. The results of dust counts on air samples taken at several locations are recorded below. The count at the forming press (Test Mo. 7) is equal to the permissible limit. The improvements outlined in Mr. Robinson's letter should be applied to this opera tion. Adequate exhaust control will not only reduce the poten tial health hazard but will also aid in correcting the housekeep ing problem. The dust count during scrap grinding (Test Mo, 11} exceeds the permissible limit. Even though this is not a continuous op eration, it would be advisable for the operator to wear a u. S. Bureau of Mines approved toxic dust respirator while grinding the scrap. Permissible Limit for Asbestos Dust Although the 'brake lining material is composed of a mixture of asbestos with other ingredients, the permissible limit is con sidered as that of asbestos. The permissible limit for exposure to asbestos dust is 5,000,000 particles per cubic foot of air. Results of Asbestos Dust Counts Test Mo._____ Location and Conditions particles per Cubic Foot of Air 7 Breathing zone at forming press 507 and bake press 508. Mo local exhaust Hanging circulating fan running 5,000,000 8 Breathing zone of employee loading feed magazines of preheat ovens. Dust arises as liners are handled and stacked 2, 000,000 9 Breathing zone between discharge of slitter and feed of grinder near preheat ovens 2 , 000,000 0004S Results of Asbestos Dust Counts (Cont'd) Test No. Location and Conditions 10 Breathing zone at ID grinder (No. ID 28963). Grinder has local ex haust 11 General condition in salvage grind ing room during scrap grinding Page 5 Particles per Cubic Foot of Air 3,000,000 11,000,000 Chromic Acid Chromic acid is used for cleaning rubber molds in Depart ment 91, Building 25. The weather strip molds are multicavity aluminum, measuring 158" x 21". Cleaning is accomplished by im mersion in a detergent tank, then a rinse tank followed by running water rinse before immersion in the chromic acid cleaning tank. Following chromic acid cleaning, the mold is returned to the rinse tank and given a final rinse, with running water and steam. Brulin 815 OR Detergent is used in the detergent tank and Brulin 618 acid mold cleaner is used in the acid cleaning tank. According to information obtained from Brulin and Company of Indianapolis, suppliers of these materials, the 815 QR is a mix ture of polyphosphates, silicates, organic detergent, emulsifier and alkanol-amines. The solution was heated to 190 F. There is no local exhaust-on the tank but direct inhalation of emitted steam and other vapors was not objectionable. The 618 acid mold cleaner is a mixture of chromic, sulfuric and phosphoric acids in water. This solution was used at 185 F. The tank surface is approximately 25* x 18" with local esdiaust slots along the top edge of the 25* dimension on both sides. Chromic acid odor was intermittently detectable directly along side the tank. Three employees occupy work stations at the mold conveyors weighting weatherstrips about 18' to 25* from the acid tank. Com plaints of chromic acid mist had been registered by one employee working at the conveyor about 18' from the tank. Tests for chromic acid were made at this station under nor mal conditions as recorded below. No chromic acid was detected. 00049 Page 6. Permissible Limit for Chromic Acid The permissible limit for exposure to chromic acid is 0.1 milligrams per cubic meter of air. Results of Tests for Chromic Acid Test No. Location and Conditions Milligrams of Chromic Acid per Cubic Meter of Air 12 Breathing zone at weather strip conveyor about 18' from acid tank while mold was in tank 13 Same location as Test No. 12 While mold was being removed from tank, rinsed and steamed None Detected None Detected 14 Breathing zone on platform alongside acid tank. Not a regular work station. None Detected Toluene diisocyanate (TDI) is used in the polyurethane foam production for crash pads and seat pads. ed in the building jadjacent Building 25. in Building 28. Crash pads are process Seat pads are produced 0 The potential hazards of TDI ar well recognized and the pro cesses are well controlled by enclosures and local exhaust at points where exposures are likely to occur, it is understood that good control is enhanced by air sampling for TDI perforated by personnel of the Chemistry laboratory. A record of air analy ses will be of value in the event of alleged illnesses Which may be attributed to TDI exposures. However, periodic scheduling of such tests, rather than an occasional survey, should be consider ed. Such tests should also be made when production schedules are increased or new equipment put into operation. Tests for TDI were made at several locations in Department 75, Building 28. The tests were taken under present production 00050 Page 7 Toluene Dilsocyanate (Cont*d) rates with only the south side of the seat cushion line in opera tion. The results, recorded below, are well below the permissi ble limit for exposure to TDI. Permissible Limit for TDI The permissible limit for exposure to TDI is 0.1 part per million parts of air by volume (ppm). Results of Tests for TDI Test No.____________Location-and Conditions TDI in ppm 15 Breathing zone of foamer operator. Ex haust slots along conveyor near this location None Detected 16 Breathing zone along conveyor in area of mold covering operation. Exhaust slots behind conveyor None Detected 17 Breathing -zone at unloading station after first pass through oven None Detected 18 General condition in area of transfer of pads from roller squeezer to convey or for final cure oven None Detected 19 General condition along conveyor where cloth strips are applied to finished pads Less than 0.01 EXPLANATORY NOTES Test Methods Trichloroethylene vapor was determined with a Davis Halide Meter. 00C51 Page 8 Test Methods (Cont'd) Air san^les for asbestos dust were collected in butanol with a Midget Impinger. Counts were made according to U.S.P.H.S. Bul letin No. 217. Chromic acid samples were collected in water with GreenburgSmith impingers. Analyses were done by a colorimetric method. 7DX samples were collected in a solution of acetic and hydro chloric acid. Analyses were done according to the method of Karcali. 00C52