Document O340kwYzkpyngkG807dz7y9me

Shell Oil Company IrrtarofTVc* Memorandum HAT 11, 1987 FROM:;' C. L..HARING, INDUSTRIAL HYGIENIST, S4IH, BSAE TO: B. X. REES, MANAGER, BUILDING SERVICES, INFORMATION CENTER SUBJECT: ASBESTOS MONITORING IN COOLING TOWER ENCLOSURE Per your request, monitoring for asbestos was conducted In the subject area on February 19 and March 4, 1987. Personal and area samples were collected during routine maintenance duties and simulation of the cooling tover cleaning procedure. In addition, a sample of residue from the tower sump was collected and analyzed for asbestos content. On February 4, the duties of the maintenance worker, Nathan Vallle, consisted -of four observation tours In the cooling tover enclosure. Each tour lasted approximately 30 minutes. ' -Vallle added chemicals to the cooling tover water and climbed to the top of the tover to check the fans once during the shift. The rest of the shift was spent on maintenance in the air handling rooms and cafeterlm. On March 4 a contract laborer, R. D. Teague (Karley Construction), simulated a cooling tover cleaning procedure. The procedure consisted of removing translte panels from one cell of the tover frame, laying them across sav horses and scrubbing them using a wet technique to remove dirt and water deposits. Thirty panels were Involved. Although not observed throughout the day, Teague claimed to have repeated the process 33 times. Each panel is approximately 3X8 feet. Teague wore a half-face piece dual cartridge respirator which, after the job was completed, was observed to be for organic vapors and not particulate aerosols. (Organic vapor cartridges are not effective against asbestos.) An inspection of the tover in December 1986 (memo from C. L. Earing to B. L. Rees, January 28, 1987) indicated that the translte panels appeared basically sound and vere not becoming friable. Little mechanical damage to the panels was noted. Monitoring results are tabulated below, Date -. - Name Sample Time (min) IZEi * -Aetlvity/Area 2/19/87 -m 425 430 Personal Atm Routine duties,' check fans Vast *md of cooling tower, S ft. from '.ground. CADS712805 ^ LAM 019418 Result <f/cc) <0.01 <0.01 ABS-000229 / Date Raae ' Sample Time (*iu) ?TPC Activlty/Area 430 Area Cooling tower stair on west and, 12 ft. froa ground. 425 . Area . _ Top of cooling tower Result (f/cc) <0.01 <0.01 3/4/87 360 Personal Cleaning panels froa cooling tower cell 357 Area East end of cooling tower during panel cleaning, 10 ft.froa work station. 355 Area South side of enclo- sure shout 20 ft. froa work station. <0.01 <0.01 <D.01 The residue collected in the cooling tower sump contained no detectable asbestos (<1.0Z). The personal and area sample results are nil belov the current OSHA standard, 0.2 f/ec (fibers/cubic centimeter) for an 8-hour time weighted average. This suggests that employees working in the area under routine conditions are not likely to be exposed to levels exceeding the OSHA standard. .However, It would be prudent on a precautionary basis for contract workers engaged in the tower cleaning activity to wear appro priate protective gear, including respiratory protection as specified by the OSHA standard. The residue fro* the tower sump will not require special handling since it contains less than 11 asbestos. Industrial Hygiene Services would like to conduct nonitoring during the cleaning operation if and when it begins. If. you have questions, please call ae at 241-2371 or Jerry Eansdell at .241-6532. CLB:BVR ec: J. 0. Kansdell/H. L. lusnetz ES&E-AS (2) CAD8712805 LAM 019419 ABS-000230