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DOW CHEMICAL U.S.A. 50983 o TEXAS DIVISION FREEPORT. TEXAS 775A1 ENVIRONMENTAL HEALTH REPORT AIRBORNE ASBESTOS SURVEY B-1040 FILE MO. BIO-309 o at f March 19, 1974 author H. N. Edwards ZZZEZCHECKED 3/ic/7<l Summary A survey for airborne asbestos was made in the B-1040 area. This is an operation that purifies crude asbestos. All analysis were below the levels required for the asbestos standard established by the Occupational Safety and Health Act, (OSHA). co CD CD cn o no Distribution H. R. Schewter B-1029 F. W. Spillers B-2224 * c L. Sercu - Cleveland G. Vaughn - Plaquemine * H. H. McClure B-1210 File (2) R. E. Flake B-101 H. H. Hoyle 1707 Bldg. Midland Cover sheet only * F. D. Axe - Pittsburg * C. E. Caldwell - OCD * R. R. Langner 607 Bldg. - Midland AN OPERATING UNIT OP THE DOW CHEMICAL COMPANY ST0014502 STOOI 4503 File No. B-10-309 -2- INTRODUCTION OSHA requires that occupational exposure to airborne asbestos dust be controlled so that no worker is exposed to more than 5.0 asbestos fibers per cubic centimeter of air based on a count of fibers greater than 5 micrometers in length. These are deter mined as a time-weighted average (TWA) exposure for an eight hour work day, and no peak concentrations of asbestos more than 10.0 fibers per cubic centimeter as determined by a minimum sampling time of 15 minutes. This survey evaluated the airborne asbestos during the purification process at B-1040. METHODOLOGY The operation procedure for mixing asbestos was observed and two stationary points were selected for monitoring, (Fig. 1). A third sample was taken by having the mixer wear a monitor during the mixing operation. Sample point two was an area on the plat form where the dry asbestos is stacked just before mixing. Sample point one is on the mixing tank. The mixer carried the bags from the crude asbestos area, placed them on a platform near sample point one. He then opened the bags and dumped them near sample point two. During the operation the test subject wore a ScottAcme respirator as a routine safety procedure. Airborne samples were then taken using the MSA portable pump (Mine Safety Appliance Co., Pittsburgh, Pa., Model 92814). The asbestos was collected by pulling air through a millipore filter. Flow rate for the pump was one liter per minute and the sample time was one hour. All analysis were done by Lee Martin B-1218. DISCUSSION Sample 1 shows 0.9 fibers per cubic centimeter and sample 2 has only 0.2. The personnel monitor showed 2.6 fibers per cubic centimeter. These measurements are all below OSHA's present requirements, but not below those that become effective July of 1976 which reduces the number of fibers per cubic centimeter from five to two. CONCLUSIONS Airborne asbestos measured during this survey was below the current Threshold Limit Values (TLV). ST0014503 File No. B-10-309 -3- RECOMMENDATIONS Even though the concentrations of asbestos measured were below the TLV, care should always be used in handling the material. Attached is a list of OSHA requirements that may be of help to you. STOOI450U ehs HNE/bbs 3-19-74 STOO14504