Document 6byXmvKxZ22kzo7njq5GNgKz3

PLAINTIFF'S EXHIBIT INDUSTRIAL HYGIENE REPORT TEXAS OPERATIONS DOW CHEMICAL USA. AN OPERATING UNIT OF THE DOW CHEMICAL COMPANY RLE NUMBER: DATE ISSUED: PLANT CODE: 824-3083A "June 28, "195 MM2. TITLE: EVALUATION OF SHORT-TERN EXPOSURE TO ASBESTOS DURING INSULATION REMOVAL, B-5400 BLOCK Coverers' and Apprentice Coverers' potential exposure to asbestos fibers during insulation removal was evaluated in November, 1987. The Coverer's potential calculated 8-hour time-weighted average exposure of 0.23 fibers/cc was marginally above the acceptable limit. The Apprentice Coverer's potential calculated exposure of 0.19 fibers/cc was slightly below the 0.2 fibers/cc level. An area sample was taken downwind at the outer perimeter of the regulated area. The concentration of asbestos was 0.19 fibers/cc. During the removal operation, the wind speed was approximately 20 to 25 MPH. The weather conditions and the inability to keep the Insulation wet is believed to be the major cause for the high levels detected. To minimize employee exposures to asbestos, the procedures outlined in the "Texas Operations Asbestos Handbook", should be followed at all times. Coverers and Apprentice Coverers should be informed of the results of this survey. The informing should be documented in writing. The original copy of the documentation should be sent to Industrial Hygiene Services, B-101. Distribution: C. K. Browdy, M.D., B-101 D. E. Cragar, B-101 G. W. Engdahl, 1803, Midland G. G. Hinojosa, B-108 *J. E. LeBeau, 1803, Midland *L. W. Rampy, 1803, Midland M. G. Swank, 1803, Midland M. L. Town, B-2403 go -H O O cn po o Insulation Shop, B-106 Cover Sheet Only RESTRICTED FOR USE WITHIN THE DOW CHEMICAL COMPANY ONLY IHS File 824-3083A Page 1 INTRODUCTION EVALUATION OF SHORT-TERM EXPOSURE TO ASBESTOS DURING INSULATION REMOVAL, B-5400 BLOCK Asbestos monitoring was done during the removal of asbestos insulation on a valve and pipe in the B-5400 block. The work was done by Coverers from the B-106 Insulation Shop. The monitoring was done to assure that the use of approved job procedures would result in acceptable airborne asbestos concentration. CONCLUSIONS AND RECOMMENDATIONS Based on the limited monitoring data, the Coverer calculated 8-hour time-weighted average (TWA) exposure of 0.23 fibers/cc was marginally above the 0. 2.fibers/cc acceptable limit. This was a potential exposure because the employee was wearing the proper protective equipment. The Apprentice Coverer, although doing the same job, calculated TWA exposure of 0.186 fibers/cc was slightly below the acceptable guideline. The removal job was done on a day when the wind speed was approximately 20 to 25 MPH. A wind barrier was used, although it appeared not be very effective. An area sample was taken downwind of the job at the outer perimeter of the regulated area. The asbestos concentration was found to be 0.188 fibers/cc during monitoring. ST00I52II Based on the employees calculated potential time-weighted average exposure to asbestos fibers, the following measures shouTd be taken: 1. The removal of asbestos insulation under extreme weather condition (etc., high wind speed) should be postponed, unless adequate wind barriers can be constructed. 2. The insulation must be kept wet continuously during removal to minimize the release of airborne fibers. 3. All Coverers should be informed of the results of this survey and the informing documented. RESULTS AND DISCUSSIONS Table I shows the monitoring results for a short-term job done on 11-6-87 at B-5400 block. The highest concentration of asbestos found was 3.73 fibers/cc for a 30 minute job. This calculated to an 8-hour time-weighted average exposure of 0.23 fibers/cc. Table II shows an area sample taken downwind at the outer perimeter of the regulated area. The concentration was found to be 0.19 fibers/cc. The weather conditions and improper wetting procedures are believed to be the major contributing factors of the high levels found during the job. IHS File B24-3083A Page 2 EVALUATION OF SHORT-TERM EXPOSURE TO ASBESTOS DURING INSULATION REMOVAL, B-S400 BLOCK METHODOLOGY Asbestos samples were collected using calibrated Gilian HFS 513A and 113A air sampling pumps. A known volume of air was pulled through 25 mm cellulose ester membrane filters, 0.8 urn pore size. Samples were collected at a flow rate of approximately 2 liters per minute. The samples were counted by McKee Environmental Health Services using NIOSH Method 7400. EVALUATION CRITERIA The evaluation exposure level was based on the following criterion: OSHA PEL Asbestos 0.2 fiber/cc The OSHA Permissible Exposure Limits (PEL) is the time-weighted average concentration for a normal 8-hour workday, 40 hour work week, to which nearly all workers may be repeatedly exposed without adverse health effects. STOOI 52 12 IHS File B24-3083A TABLE I SUMMARY OF INDIVIDUAL POTENTIAL SHORT-TERM EXPOSURES TO ASBESTOS INSULATION DURING REMOVAL Job Classification Coverer Apprentice Coverer Master Sample Number Number Date Sampling Concentration TlmefMlnl Flbers/cc 135817 A-ISB-1 11-6-87 30 3.73 8-Hour TWA 0.23 142947 A-ISB-2 11-6-87 30 2.98 8-Hour TWA 0.186 Industrial Hygiene Guide 8-Hour TWA 0.2 STOOI52I3 IHS File B24-3083A TABLE II AREA SAMPLE POTENTIAL SHORT-TERM EXPOSURES TO ASBESTOS INSULATION 0URIN6 REMOVAL Sample Number A-ISB-3 Sample Description Area sample taken downwind at the outer perimeter of the regulated area. Date 11-6-87 Sampl1ng Concentrat1on TlmefMinl FI hers/cc 38 0.188 CO o o cn PO