Document GNQxDDodnYxDJVqnKKD95bNx

Ej D i o Vj 50983 ^. -o _ a -7V33/ DOW CHEMICAL U.S.A. TEXAS DIVISION FREEPORT, TEXAS 775A1 ENVIRONMENTAL HEALTH REPORT AIRBORNE ASBESTOS CELL MAINTENANCE AREA CHLORINE 5, BUILDING A-1324 file no. A13-93Q_____________ ,,ATP September 1, 1976 AUTHOR. H. N. Edwards CHECKED DATE ScJ: 2. Summary Airborne asbestos levels measured within the Chlorine 5, Cell Maintenance area are below the pre sczritscl 2.^-hlL'wS On me st occasions they were below the newly" proposed limits and with a little care for detail and better housekeeping these levels could be met. Even though these levels are low, there is still a potential for over exposure therefore, your present protective equipment program is still recommended along with improved housekeeping and regular .monitoring. to o o CD CO CO Distribution S. F. Edquist B-2401 R. E. Flake B101 W. H. Fletcher B101 G. D. Heiniger B-1226 Chuck Hill A-1324 A(2) RlLangner 1803 -Midland Marlene Swank 1803 Midland * F. D. Axe - Calif. * C. H. VanMetre-OCD * C. E. Halphen - Plaquemine R. D. Olson 433 -Midland John Martino - Licking River 0. F. Schumm B101 J. A. Van Westenberg A-606 File AN OPERATING UNIT OF THE DOW CHEMICAL COMPANY 408814 File A13-930 -2- September 1, 1976 INTRODUCTION The Occupational Safety and Health Act (OSHA) requires that occupational exposures to airborne asbestos be controlled sc that no worker is exposed to more than 2.0 asbestos fibers per cubic centimeter of air based on the count of fibers greater than 5 micrometers in length. These are determined by a timeweighted average (TWA) exposure for an eight hour workday, and no peak concentrations of asbestos more than 10.0 fibers per cubic centimeter as determined by a minimum sampling time of fifteen minutes. It has now been proposed to lower the limit to 0.5 fibers per cubic centimeter with a peak exposure of 5.0 fibers. This survey was conducted at the Chlorine 5, Cell Maintenance area over a period from December 20, 1975 - August 17, 1976. METHODOLOGY After discussion with supervision it was decided to see what effect a good cleaning would have on the background levels of airborne asbestos in the Cell Maintenance areas. Pre-wash down samples were taken on December 29, 1975 and December 30, 1975. The building was washed including the ceiling, walls and floor and sampling was repeated on March 16 and 17, 1376. The Cell Maintenance area was again sampled on August 16 and 17, 1976 to evaluate the overall levels and particularly around the vat area during drawing. The exposure level on the tow motor was also evaluated. Airborne samples were collected using a Bendix Permissible Air sampling pump (Bendix Corp., Baltimore, Md.). The fibers were collected by pulling air through a Millipore filter (AAWG6 03700) mounted in an open face Millipore disposable cassette. Flow rates for the pumps were calibrated at 1500 cubic centimeters per minute and sample times are shown in Tables I-V. Samples were analyzed by Lee Martin of Central Laboratories using the following technique: Four marked squares are cut from a filter about half way from the edge to the center. Thi| section is then placed on a drop of clearing solution'1' and placed on a microscope slide. The sample is covered with a cover slip and allowed to clear (about 15 minutes) . The sample count is made on a Reichert Zetopan Optical microscope using Normarski interference contrast at 500 magnification. Counts are made for particles greater than 5.0 microns and reported as fibers per filter square. 1 Clearing solution: 0.1 g/ml of clean Millipore filter pacer in 1:1 diethyloxalate: dimethylphthalate 408815 s T 0 0 0 3 lh 9 File A13-930 -3- September 1, 1976 RESULTS Table I shows the levels of airborne asbestos before and after the cleanup with no activity in the Maintenance area. Table II contains the results of airborne asbestos when activity is goin on in both AM and PM. It is worthy to note that four samples were above the proposed 0.5 TWA but none above the 5.0 peak. Table III shows results made near the drawing vat. Here again a number of samples were above the TWA but not the peak. Table IV are levels on dry cathodes, at the drying oven and on a tow motor. When the oven is opened some dry asbestos always seems to escape. Also, the tow motor seems to stir up asbestos as it moves about. Table V is a result of normal working for a 180 minute period. Again the mixing room (where dry asbestos is handled)is high as well as the area around the drying oven. DISCUSSION T^e vTs.si^ovTii of fhw T"'j clxd ^ ^ v* +* ^ m i Qwori +-Vio i of asbestos fibers. They were probably lowered more than these results show since the pre-cleaning time was a damp period (Table I) . When sampling with activity going on (Table II) the levels do increase, but with the exception of area 6 (which is near the mixing-vat and drying oven the- levels are below the 0.5 fibers. During this test period there was much loose asbestos in the mixing room and lots of dry asbestos on the floor around the vat area. These probably contribute to the high levels in area 7 also. The mixing vat area at times was very sloppy. During the operation the vat spilled over and the wet asbestos was all over the floor of the vat platform and the area below the platform. Most of this spill was cleaned up in the a.m. but by the p.m. there was still lots of loose and dry asbestos in the area. There was some dry asbestos in the area before the vat operation began. (Table III.) The results for the drying oven, dryed cathodes and the tow motor were as expected. The drying oven when opened releases for a few minutes, fibers into the atmosphere, but this level seems to decrease shortly after the cathode is removed. The area around the oven seems to be stirred by an air current that flows in that area. ST0003I 50 408816 File A13-930 -4- September 1, 1976 DISCUSSION (continued) The dry cathodes seem to produce some loose fibers even though they are bended. For how long these loose fibers are produced is not known, but the area measured on August 16, 1976 (Fig. 1 #15) contained three cathodes from the previous week. These same cathodes were still in place on August 17, 1976(Table IV). When the tow motor was not in operations it was monitored in the location shown in figure 1. During the work period it was used throughout the Maintenance area. When loose asbestos in on the floor this machine seems to grind and powder it even though it is bonded. This caused the fibrous particles to be spread throughout the Cell Maintenance area. Even with these levels which are below the TLV limits or peak exposure limits, precautions are taken. The employees wear an approved respirator when working in the mixing room, when open ing the drying oven and when working in the vat area. This is done because of the potential for overexposure. CONCLUSIONS There is a potential for overexposure while doing some tasks within the Chlorine 5 Cell Maintenance area, but employees are probably not being overexposed because proper protection is used. It may also be concluded that the cleanup does reduce the normal background levels. RECOMMENDATIONS 1. It~is recommended that a better housekeeping policy be used. When a spill occurs it should be properly cleaned up immediately. Loose asbestos or broken chunks should be picked up and properly disposed of before the forklift runs over them. 2. It is also recommended that the area be totally cleaned on a periodic basis; that is, ceilings, walls, equipment, etc. 3. Broken bags of asbestos should be picked up and sealed immediately. The mixing room should be kept free of loose asbestos when not in operation. 4. It is further recommended that your present program of personnel monitoring be continued and that all personnel in the Maintenance area be included. ST0003I5I EHS HNE/bbs 9-1-76 408817 TABLE I BACKGROUND ASBESTOS LEVELS CHLORINE 5 LOCATION FIG. 1 #2 3 4 5 6 FIG. 1 #2 3 4 5 6 FIG. 1 #2 3 4 5 6 FIG. 1 #2 3 4 5 6 DATE BEFORE CLEANING SAMPLE TIME 12-29-75 12-29-75 12-29-75 12-29-75 12-29-75 180 min. 180 min. 180 min. 180 min. 180 min. 12-30-75 12-30-75 12-30-75 12-30-75 12-30-75 240 min. 240 min. 240 min. 240 min. 240 min. AFTER CLEANING 3-16-76 180 min. 3-16-76 180 min. 3-16-76 180 min. 3-16-76 180 min. 3-16-76 180 min. 3-17-76 3-17-76 3-17-7 6 3-17-76 3-17-76 180 min. 180 min. 180 nun. 180 min. 180 min. FIBERS >5.0 MICROMETER/c C 0.10 0.11 0.08 0.46 0.38 0.23 0.18 0.22 0.52 0.59 0.006 0.002 0.008 0.007 0.100 0.008 0.008 0.008 0.009 0.180 U U U J I O c. Weather Outside December 29 ----- wet and cold December . 30------- dry and cold March 16------------- warm and dry March 17------------- cool and dry 408818 TABLE II ASBESTOS LEVELS CHLORINE 5 ACTIVITY ON FLOOR A.M. LOCATIONDATESAMPLE TIME #1 Aug. 16, 1976 30 min. 2 Aug. 16, 1976 30 min. 3 Aug. 16, 1976 30 min. 4 Aug. 16, 1976 30 min. 5 Aug. 16, 1976 30 min. 6 Aug. 16, 1976 30 min. 7 Aug. 16, 1976 30 min. 8 Aug. 16, 1976 30 min. FIBERS >5.0 MICROMETERS/C 0.019 0.220 0.310 0.280 0.260 0.760 0.800* 0.230 ACTIVITY ON FLOOR P.M. #1 Aug. 16, 1776 30 min. 2 Aug. 16, 1976 30 min. 3 Aug. 16, 1976 30 min. 4 Aug. 16, 1976 3 0 min. 5 Aug. 16, 1976 30 min. 6 Aug. 16, 1976 30 min. 7 Aug. 16, 1976 30 min. o Aug. xo, 1976 3 0 min. 0.031 0.028 0.202 0.288 0.350 0.820 0.710* 0.200 b I U U U JID J * No activity inside area Weather: August 16, 1976----------- dry and hot 408819 TABLE III ASBESTOS LEVELS NEAR VAT CHLORINE 5 BEFORE FILLING VAT LOCATIONDATESAMPLE TIME FIBERS > 5.0 MICROMETERS/CC #9 Aug. 16, 1976 30 min. 10 Aug. 16, 1976 30 min. 11 Aug. 16, 1976 30 min. 12 Aug. 16, 1976 30 min. 13 Aug.- 16, 1976 30 min. 0.620 0.418 0.135 0.096 0.212 DURING FILLING OF VAT #9 Aug. 16, 1976 30 min. 10 Aug. 16, 1976 30 min. 11 Aug. 16, 1976 30 min. 12 Aug. 16, 1976 30 min. 13 Aug. 16, 1976 30 min. 0.516 0.522 0.280 0.116 0.209 WHILE DRAWING VAT #1 #9 Aug. 16, 1976 30 min. 0.313 10 Aug. 16, 1976 30 min. 0.220 11 Aug. 16, 1976 30 min. * 12 Aug. 16, 1976 30 min. 0.386 13 Aug. 16, 1976 30 min. 0.089 #2 0.280 0.218 0.088 0.521 0.115 AFTER DRAWING VAT (P. M. ) #9 Aug. 16, 1976 30 min. 10 Aug. 16, 1976 30 min 11 Aug. 16, 1976 30 min. 12 Aug. 16, 1976 30 min. 13 Aug. 16, 1976 . 3 0 min. 0.716 1.120 0.515 0.318 0.302 u * Water sprayed on filter Icnnn i 408820 TABLE IV ASBESTOS LEVELS CHLORINE 5 LOCATION FIG. 1 #14 15 16 BEFORE ACTIVITY DATE SAMPLE TIME Aug. 16, 1976 Aug. 16, 1976 Aug. 16, 1976 30 min. 30 min. 30 min. DURING ACTIVITY 14 Aug. 16, 1976 15 Aug. 16, 1976 16 Aug. 16, 1976 30 min. 30 min. 30 min. FIBERS >5.0 uM/CC 0.802 0.316 0.228 * 2.101** 0.392 0.805 *' * Tow motor not moving ** Dry cathode removed *** Tow motor working ST0003I 55 408821 TABLE V ASBESTOS LEVELS CHLORINE 5 NORMAL WORKING LOCATIONDATESAMPLE TIMEFIBERS >5.0 uM/CC #1 Aug. 17, 1976 180 min. 2 Aug. 17, 1976 180 min. 3 Aug. 17, 1976 180 min. 4 Aug. 17, 1976 180 min. 5 Aug. 17, 1976 180 min. 6 Aug. 17, 1976 180 min. 7 Aug. 17, 1976 180 min. 8 Aug. 17, 1976 180 min. 14 Aug. 17, 1976 180 min. 15 Aug. 17, 1976 180 min. 0.029 0.016 0.332 0.201 0.350 0.412 0.520 0.181 0.885 0.289 Weather: August 17, 1976------- Hot and dry ST0003I 56 408822 MIXING ROOM ST0003 I 57 DRY CATHODES :3 TOW MOTOR c p FIGURE 1 408823