Document 3nLn5GRd68k6M2VBe9QGBwmD

FILE NAME: AT&T and other Phone Companies (ATT) DATE: 1977 Mar 30 DOC#: ATT002 DOCUMENT DESCRIPTION: Memo  f-0 3 1 Asbestos Exposures During Brake Changes Case: ^81063___ KEMQRARPPH FOR RECORD ft. D. Kenney 70f Introduction Heaevirements for asbestos were taken at three different garages in the Miami District on December 1?2, 1976 In addition* measurements for lead, tin and copper were taken in one garage where a worker was welding and grind lng on a truck which vac undergoing extensive bodywork. Procedures She asbestos samples were collected using the procedures outlined both by the National Institute of Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). Basically the procedure involve collection of the fibers on a Bmall filter* with later analysis using phase contrast or transmission electron microscopy. The samples for metals were collected in a similar manner. The filters used for collection of the samples were either 37 ram Millipore cellulose ester filters, or 37 mm Nuclepore polycarbonate filter. Both filter types have nominal pore diameters of 0.8 micrometers (pm). i Air w o b pulled through the filters using battery powered sampling pumps manufactured by Bendix. The pumps were calibrated using the soap bubble flowmeter technique. The cellulose filters were analysed using phase contrast microscopy while analysis of the polycarbonate filters was performed using transmission electron microscopy. Analysis for the metals was performed using the procedure of atoaio absorption spectroscopy. Background During the course of this survey measurements were taken at three different garages. Hough sketches of the garages are attached. BOelFlFTIeClIeAphLonFe ILLaEboCraOtoPrYies 1NCORPOAATB .- 2 The main Jobs being performed at garages 1 and 3 during the time measurements were being taken was annual pre ventive maintenance examinations of the vehicles. These , inolude visual examination of the brake linings with f replacement if necessary. At garage #2 welding, torching and grinding was being performed on the vehicles as well as the annual preventive maintenance examinations. In all cases the vehicles being examined were 3/4 or 1/2 ton vans. pulled the In addition, once the brake drum and backing plate were drum has been cleaned by blowing out out the duat using compressed air. The total time it ) took to check the brakes and mount new linings* if necessary, was ^0 to 60 minutes per truck. . R esults The results of the phase contrast analysis are presented in Table I while results of the electron microscopic analysis are presented in Table II, Table III presente the results of the metal analysis. Briefly,, the results of the metal analysis indicate that during the operations of grinding, torching, and welding insignificant amounts of metal fumes and or dust are generated* The levels measured were well below the appro priate OSHA standards for lead,(200 ug/m3), tin {2000 jig/3), and chromium (1000 jig/3). The results of the phase contrast microscopy analysis, presented in Table I, indicate that a definite exposure to asbestos fibers occurs during the operation of changing brakes* Three of the samples, one taken for a period as short as 12 minutes, has dust concentrations too heavy for an accurate count to be performed. The remaining personal samples gave values between 0.16 and 0.24 fibers longer than Sum per cc of air. These values are elevated over the i one ambient sample of 0.02 fibers/oc and the blind blank with an assigned value of 185 1 of <0.015 fibers/co. The results of the electron jaioroeeoplc esmlyoia are presented In Table II. They indicate that of the five general air samples collected* including the ambient, aabestiform fibarc > $ j*is 1 length ware detectable oh only one sample; on this sample, tko .concentration was S.24 fibers >5 jhs/cc. Ha-75S5-GBX-Jm E -7 7 70-A M -6& > 0 , r-\ Kenney BOelFlFTICelIeAphLonFe ILLaEboCraOtoPrYies lNC0fcP0AATC0 ; 3 The one personal sample analyse* by electron microscopy Indicated an asbestos concentration of 1,04 fibers >5pra/ac> during th eleven minutes necessary to blow out the brake drums. This level indicates that an occupational exposure to aBbeBtoa does occur during the blowing out process, a conclusion that correlates with the phase contrast microscopy results. Summary As a result of these measurements it is evident that an exposure to asbestos fibers.oceurs during the operation ) of inspecting and/or changing brakes, toons noter e possible, engineering means to control the exposures should be investigated. In addition, the employees should be afforded medical examinations where possible. / ORIGNAL S '* '" " ' Vii h SCI Q. ), Tables I, II, III Copy to B, M. May - A.T.&T. Vf, J. Schreibels - BTL R. Vi. Stone, M.D. - A.T.&T, 0. M. Wilkening - BTL C v vy v o -A c4-ecv OFFICIAL. FILE COPY Beu. TlIpNhCOofntrORALtaEbDoratories