Document g2DeNOvJ1pBG6xJq8kw19bBKa

(conoco) Interoffice Communication to J. A. De Bernardi From P. L. Fetzer Date December 18, 1979 Subject Deregulation of Area No. 5 - EDC Tank Tops The data developed by Jay Zimmer during the summer indicated that all tanks except T-453 could be deregulated based on the 8-hour test data. However, since employee exposure occurred within a 15-minute time period, the exposure data for this time period was developed. The earlier data summarized below showed that all tank tops except T-453 and T-402 were below the 5.0 ppm VCM 15-minute maximum exposure value. ppm VCM T-402 5.39 T-405 1.20 T-460 2.81 T-450 0.28 T-451 4714" T-452 3.99 T-453 22.8 Tanks T-402 and T-453 were retested following mechanical check-out and completion of any required maintenance work. Six 15-minute testings of each tank were completed. The average.value of the composite testings is 1.2 ppm and 0.52 ppm respectively for tanks T-402 and T-453. Personnel exposure data for the Pumper-Loaders Offsites whose duties require them to be atop of the EDC tanks are tabulated beTow. The high values are not attributed to helping the pumper-loader on the loading rack. Two exposures occurred on the shift where the pumper-loaders are atop the EDC tanks but one was attributed to general high area levels and the second to loading a light ends tank car. 0.0-0.5 21 0.5-1.0 2 ppm VCM 1.0-2.0 1 2.0-3.0 0 3.0-4.0 0 4.0-5.0 2 The original basis for the regulated area was due to the vinyl in the vent gas being omitted atop each tank. Now all EDC tanks are vented into a vent system that is connected to the incinerator reducing exposure atop the EDC tanks. Those maintenance problems which were corrected atop T-453 directly led to the reduction of the recent 15-minute test data. Based on the recent test data, the EDC tanks T-402 and T-453 should be dere gulated. All other tanks should be deregulated on the basis of the earlier data. Paul L. Fetzer PLF:lad CC: GLF, WVH, HDG DTH 000013963