Document 2e2KmOGNq1MdjYX697RKnR9N

lI 60383 C DOW CHEMICAL U.S.A. PLAINTIFF'S EXHIBIT TEXAS 5IVISICAJ pt?FPPORT. T:XAS ?75ll ENVIRONMENTAL HEALTH REPORT ASBESTOS MONITORING MAGNESIUM III 3-800 c fiie ho. B8- L702 nirr January 26 , 1979 author - ' Whatley r-------------------------------- ___________________ rn-'rrKpr; 2-> cate -LLit-A/j . Summory A, survey was conducted Lo evaluate employee exposures to asbestos fibers during a plant shut down at Magnesium til, B-oOO, on November 28, 1978. All potential employee exposures were well within the permissible exr-osure limit. Monitoring should be repeated during the next plant shut-down. Employees should be informed of the results of this survey, and the informing documented. 09Znnn i s Di Jl^Suiicn J. E. Grau 8-815 A.. L. McDowell B-101 Toler R-815 L. W. Rair.py 1803 Midland R. R. Langncr 1603 Midland Marlene Suank 1803 Midland D. .1. Roberts 2020 Midland * F. 0. Axe - Pittsburg * C. E. Halphen - Plaquemine * R. J, McCormick - Strongsville * Neil Murray - Sarnia * R. 1). Olson 607 Midland * S. A. Goodu - OCD AM OPCrjATIMQ UNIT OP THE DOW CHEMICAL COMPANV File 3S-1/02 r C January 26, 1979 INTROnrr.TTON At the request of supervision, a survey was conducted at Magnesium III, B-SOO, on November 23, 1978, Co evaluate, employee exposures to asbestos fibers during a planned plant shut uuwn far electrical repairs. PROCESS DESCRIPTION At Map.oesium ITT, molten magnesium -_s produced electrolyttea Ily from mag nesium chloride in n hath of mixed snlrn. By-products of the process are chlorine, hydrogen chloride (both arc. removed by a vacuum system), magnesium oxide, water vapor, and cell sludge- Magnesium chloride Is fed to the calls via an automated conveyor syscem, and other salts are manually poured from bags into the cells. Vanadium pentoxide, an additive which increases cell efficiency, is added to the cells in sealed plastic bags. Molten magnesium is pumped from wells at the front of the cells inco a crucible in che base ment, which is then transferred to che casting plant. Asbestos paper has two major uses at Magnesium III. It is used in small quantities (generally one piece at a time) when cells are being patched by che Running Repair Operators. A piece of asbestos paper is corn to cover the hole being patched while the employee takes a short break to cool off. The purpose of the paper is to keep the metal around the hole from freezing, and to keep the cell sealed to Insure that suction on che cell can be maintained. In general,a given Running Repair Operator patches cells about every two weeks. Once or twice a year, the plant is shut down(usually two buildings at h time) for major electrical repairs. On these occasions, several employees tear pieces of asbesLos paper to cover the metal wells and plug ihe feed and suction pipes. It cakes 3-9 employees abouc an hour to cover the ceils in two buildings (approximately 60 cells), and from 1/2-1 hour to remove and dispose of the paper after repairs are completed. The plant shutdown clearly represents the highest potential employee exposures to asbestos fibers, and is the procedure which was monitored in this study. METHODOLOGY Personucl samples were collected during both handling procedures (covering cells and paper removal) to determine employee exposures to asbestos fibers. The samples were collected by drawing a measured, volume of air (approximately 1.5 liters per minute) at employee breathing zone height through aerosol filters (Kllliporn MAWG 937AO) with jendix Micronair IT sampling pumps. The pumps were calibrated before and after use with a calibrated brocks rotameter. Fibers were counted using optical microscopy by Central Laboratory, B-1225. ST0003261 Kile t>8- L70? ( c January 26, '079 EVALUATION CRITERIA Permissible exposure limits (?3L's) are concentrations ot airborne substances to which nearly all employees may be repeatedly exposed through out a working lifetime without adverse effect. Moot POL's arc tineveighted average concentrations for 3 to 12-hour work days ar.d iG-hour work weeks. Permissible exposure limits do not represent tine lines between safe and dangerous exposures; they are based or. industrial experience and experimental human and animal toxicological studies, and are intended toe use as guides tor plant design and for evaluating employee exposures. The permissible exposure limit for asbestos fibers is two fibers per cubic centimeter of air (2 fibers/cc), as an eight-heur time-weighted average. An asbestos fiber is defined as a particle greater than or ecual to five microns in length. Ten fibers/cc are allowed as a ceiling concentration for periods up to 15 minutes.provided the exposure for the entire 3-12 hour work day does r.oc exceed 2 fibers/cc, and there are r.o more than four excursions per day, which arc separated by at least tn hour. DISCUSSION The results of the personnel monitoring for asbestos fibers are shown in Table 1. All potential employee exposures (nose-mouth respirators uece worn during the entire procedure) to asbestos during the handling procedures were well within the permissible exposure limit of two fibers per cubic centimeter of air. The highest potential exposure was about 2Q of the allowed level; however, all others were 5Z or less. C0KCLL'STC1!S_AXD RECOMMEKDATIOHS Employees at Magnesium III are not being overexposed to asbestos fibers. The highest potential exposures occur during plant shut downs once or twice a year, and are well within the permissible exposure lirniL. It is recommended that nonircring be repeated during-the next plane shut down to further substantiate the results of this survey. Monitoring for asbestes fibers during cell patching procedures is nut necessary at this time. It is also recommended that e:ap_oyees be informed of the results of this survey, the consequences of overexposure to asbestos fibers, methods of control, and the care and use of respiratory protective equipment. This Informing process should be documented. 292S0001S . EHS EPli/lihs 1-26-79 File 33-':70: c TABLE I ASBESTOS MONITORING RESULTS SAMPLE NO. B3-1702-1 2 j 4 5 6 -7 3 9 10 EMPLOYEE Mi\S TER K0 140319 133302 134916 135541 140319 135541 135541 140319 1411S0 141298 DATE 11-23-78 11-23-73 11-23-73 11-23-78 11-28-73 11-26-78 riMEGlIX.) 45 50 -- 25 -- 17 A S RESIGN CO-VC F.NTRATTOM (FI3ERS/CC) 0.065 0.07 3 pump stopped 0.34 pump stopped n.08f) 11-23-78 11-28-78 11-2S-78 11-28-78 36 61 48 34 0.040 0.044 0.099 0.0C7 Permissible exposure limit ( fibers/cc air)* 2 * 8 hour time-weighted average Samples 1-6 represent cell covering procedures; 7-10 were collected during paper removal snd disposal. ST0003263 f COKSEOUEKCES OF OVEREXPOSUF.E COHPOUvlD: Asbestos EXPOSURE LIMIT: 2 >5fibers/ml , microns in length ODOR: NONE EYES: Contact with the dust can cause irritation SIMILAR TO THAT CAUSED BY SIMILAR FOREIGN BODIES. INGESTION: Some evidence indicates that swallowed asbestos may increase chances of stomachCANCER. DUST INHALATION: j Short Term: Inhalation of high concentrations of the dust may cause moderate DISCOMFORT. INHALATION OF MODERATELY HIGH CONCENTRATIONS 'MAY CAUSE NO DISCOMFORT. Long Term: Inhalation of the asbestos fibers in conjunction with smoking has been SHOWN TO INCREASE CHANCES OF LUNG CANCER BY ABCUT 90 TIMES THAT OF A PERSON WHO NEITHER SMOKES NOR WORKS WITH ASBESTOS. CAN ALSO CAUSE A SERIOUS LUNG DISEASE CALLED ASBESTOSOS. Can also cause cancer of the LINING, COWOTS: Proper respirator is required when working with asbestos. 00032614