Document Nej8xrLvVpdRYB5knkaE1ezEE

FILE NAME: Dow Chemical (DOW) DATE: 1973 Apr 24 DOC#: DOW018 DOCUMENT DESCRIPTION: Environmental Health Report - Asbestos Fibers While Cutting Gaskets SECTION 9 DOW CHEMICAL /ATMOSPHERIC CONCENTRATION OF ASBESTOS FIBERS WHILE CUTTING GASKETS 4/24/73 I PLAIN TIFF'S EXHIBIT BO W -159 Cef f:le. DOW CHEMICAL U.S.A. 5Pgg3 TEXAS DIVISION F U E E M r T, T E XAS 77541 ENVIRONMENTAL HEALTH REPORT Concentrations of asbestos in-the general atmosphere during the cutting of gaskets was found to be border line when compared to the Federal Regulation, but may be significant when considering possible carcinogenesis. Attached is a copy of the survey with recommendation to reduce the atmospheric asbestos fiber concentration. ^pistfifcotien Billy Parrack File A-2431 A N .OPERATING UNIT O F TH E SOW CHEM ICAL ANV File No. A24-173 -2- ST0652937 PROBLEM A t the request of supervision, Industrial Hygiene was asked to evaluate the Asbestos hazard presented by the cutting of gaskets in A-1876. CONCLUSION (1) Asbestos fibers are liberated by the gasket cutting operation in significant quantities and found in the atmosphere throughout the building. (2) the concentration: of asbestos fibers found were as followst (a) Breathing zone of man doing the cutting-- -- A .03 f/cc (b) Breathing zone of man cleaning up area with broom------------------------- ------------- 2.04 f/cc (Note: Area has not been cleaned up for several days) (c) At top of stairway 15 1 from cutting table-- 5.44 f/cc .(d) Breathing zone of man cleaning table off-- 3.08 f/cc with broom and picking up material off floor with a scoop. NOTE:(a) * (d)were taken, when the area had not been cleaned for several days (e) Breathing zone of man doing the cutting----.78 f/cc () At top of stairs 1 5 1 from cutting table-- -- 0 f/cc (g) In middle of shop downstairs during cutting- .12 f/cc (h) Breathing zone of man doing cutting-- --- -- .90 f/cc NOTE: (e) thru (h) were taken after the upstairs area had been cleaned up. Current government regulations allow no mpre than an 8 hour time weighted average concentration of 5 f/cc. The regulation also states that no employee shall be exposed at any time to airborne concentrations of asbestos fibers in excess of 10 fibers/cc. (3) The current regulations governing permissible exposure to asbestos are based upon the possibility of contraction of asbestosis. Asbestos fibers, however, have also been shown to be carcinogenic. No dose/disease relationship has been established, so efforts must be made to reduce and eliminate, if possible, the workers exposures. ST0652938 File No. A24-173 -3- RECQtMENDATIONS (1) The gasket cutting device should be equipped with dust collection devices. ,(2) Cutting of gaskets should be done in an environmentally seperate area from the rest of the work area, to reduce exposure o f other: employees* (3) The m a n assigned to cutting gaskets shall wear an approved duqt respirator. (4) Work clothing should be changed and washed daily. (5) * A suitable periodic medical examination program should be arranged for employees exposed to asbestos fibers. (6) Environmental measurements should be made annually to determine the adequacy of precautions*. DISCUSSION Asbestos fibers inhaled over a prolonged period can cause a pulmonary disease called asbestbsis. This fact has been recognizedfor many years by those Involved in the production and sale of asbestos. During the last few years a threshold limit value has been established for asbestos fibers in the atmosphere, the purpose of which is to prevent asbestos workers from contracting asbestosis.* The current standard is 5 fibers/cc as recognized by the Federal Government. However, over the last few years respirable asbestos fibers have been recognized as being carcinogenic. A dose/disease relationship has not yet been established, so efforts must be made to reduce and eliminate the worker1s exposure. For this reason exposures must be reduced to as low level as is possible. This_is done most desireably by reducing the exposure to the workers, and then providing protective equipment if the exposure cannot be eliminated. A total of 8 samples were taken on Milliport 0.8 micron 47 mm AAWG membrane filters. -MSA Monltaire portable vacuum pumps calibrated and used. Used filters were cropped into 4 grid sections and immersed in 10% solution of diethyl oxylate and dimethyl phthalate .on a slide, and then covered with a cover slip. When the membrane became transparent counting was performed using 40X objective.and a 12.5X eyepiece, for a total magnification of 500X. The eyepiece was equipped with a micrometer of 100 divisions 2.5 microne each. Phase contract illumination was used. File Ho A24-173 -4- DXSCUSSIQN (continued) It should be remembered that the numbers given as the concentrations of atmospheric asbestos fibers is. not to be considered as the absolute concentration, but the best technique presently known. Tests have shown that this method produces numbers that are difficult to reproduce from lab to lab, or microscopist to microscopist. However, it is: the best technique we. have. ST0652939 SSLP bbs 4-19-73 File No, A24-I73 5*- ST06529t>0 ASBESTOS IN ATMOSPHERE DURING CUTTING OF ASBESTOS GASKETS Filter Factor = 154 SAMPLE TIME (min.) SAMPLE. RATE L/M TOTAL VOLUME tt) 1 3 2.57 2 2 2.69 3 3 2.69 4 3 2.57 10 1 rain. 10 sec,. 2.69 20 1 rain. 10 sec. 2.57 30 3 2.57 40 3 2.69 50 -0- -0- 7.71 5.38 8.07 7*71 3.13 2.99 7.71 8.07 -0- Concentration = Total Fibers Total Volume * Fibers * cc FIBERS 75 u PER SQUARE (1) 204 (2) 72 (3) 288 (4) 156 (10) 16 (20) 0 (30) 2 (40) 48 (50) 0 FILTER FACTOR 154 154 154 154 154 154 . 154 154 154 TOTAL FIBERS 31416 11,088 44,352 24,024 2464 0 308 7392 0 FIBERS PER cc 4.03 2.04 5.44 3.08 .78 0 .12 .90 * 0 ENVIRONMENTAL s u S T o t* * . #*... W MCCH . CM O AC.*1. 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