Document GK9xknVZXnvozjM0NoQZ8jnKr

FILE NAME Brakes BRK DATE 1985 DOC BRK169 DOCUMENT DESCRIPTION EPA Memo RE Asbestos Exposure - Brakes and Ambient . STDATSTEATESS al STATES = KHTAL Aaya KHTAL wait MEMORANDUM y ; \> D.C. UNITED STATES ENVIRONMENTAL AGENCY PROTECTION AGENCY == WASHINGTON 20460 05 31 31 PM 65 OCT 17 17 1985 - OFFICE OF POLICY PLANNING AND EVALUATION SUBJECT FROM TO Asbestos Exposure - . . Steve Weil Chief Chemical Review and Brakes and Ambient Stave Stave Analysis Branch Lynn Lynn Delpire Exposure Assessment Branch Amy Moll Regulatory Impacts Branch . Ail . : ca After careful examination asbestos dust from brake relining Brake Shops There is a significant amount of on worker exposure to asbestos in monitoring data available This data shows various levels of shops doing brake maintenance the operation involved asbestos exposure depending on distance from the e.g. blowing dust from brakes the - being done in the actual brake work and the amount of brake work shop a peak sample taken The numbers ranged from 29.8 cc for Rohl et al 1976 during a high blow out of number even dust from brake linings for this operation to low numbers such as .002 ec fibers length for greater than 5 micrometers in drum brakes a twa for complete service of front and .001 cc six feet outside of disk and rear 1980 Allied Brake Shop the work bay Roberts ' We have decided that the number 0.04 cc is a chosen by the contractor in shops doing reasonable brake estimate of the exposure of workers work While the number may be low for workers during the time maintenance we think thaatctuiatlly engaged in brake repair and exposure to the population of ralellamteicvhealnyicascca unrdatweolrykerresfleicnts the repair shops fie -2- A more accurate method of determination of such exposure would involve determination of exposures of workers during diffe- rent phases of actual brake work and calculation of their exposure and then addition of the rest of the exposed work force at levels that approximate background levels in the shop Rough calculations show that this yields approximately the same average exposure Ambient Exposure to Asbestos The purpose of calculating ambient exposure to asbestos is to include benefits not captured by the models Thus the ambient exposure calculation should be based on exposure data that does not include either exposure to friable asbestos in buildings already banned or asbestos floor tiles a separate calculation The calculation by the NAS pg 219 in Asbestiform Fibers Nonoccupational Health Risks is not valid for our purposes as it assumes a certain contribution to ambient from exposure to friable asbestos Further the calculation is flawed because the exposure measurement for uncontaminated indoor environments came from buildings with friable asbestos in other rooms The resulting cross contamination yields figures that are not truly representative of uncontaminated indoor environments The seems to has some ings and counting NAS figure for outdoor ambient exposure 0.00007 cc be a reasonable figure While this exposure undoubtedly component deriving from friable asbestos use in build- so on use of this figure will minimize the double problem * c.c. Debi Dobkowski Al Jennings Rick Tinsworth