Document QgJXYjorR3Q7MZgrpDX1q99V7

urrlbt UlM THE DOW CHEMICAL COMPANY t, LLCuMMl L1ITIH AMI 81NWT RISTRICTID c X a NBH2.12-28-1(1) FOR (SI OF DOW iMPlOYttS ONLY ACCT: 377 MIDLAND, M 1 C H 1 6AM Chemical Biology Research G. 5. Flores -^W-7 J OATI May 15, 1973 SlfllTU nUiIII 9080003 I EXPOSURES TO S^BROUS DUST DURING THE HANDLING OF ASBESTOS AND CaD CiN GLASS FROM INSULATION INFORMATIVE SUMMARY WITH CONCLUSIONS^ Measurements of fibrous dust levels were made during the installation of insulation from process equipment. During the s removal of asbestos insulation, exposures to asbestos fibers could exceed the maximum allowable concentration. Respiratory 1 protection is recommended when removing asbestos insulation and if feasible, wetting down the insulation is also recommended to minimize the dust levels. During the installation of fibrous glass insulation, the fiber concentrations were at safe levels. ST0000955 REVIEWED BY 0 EPA RTmENT C.R. I. MtMlaatf C R. I. Tmi CR.I. V'ttarn C R.I. !><tiR liSUEO TO ATTENTION OF DEPARTMENT 5aa4 ail 4 eaita ra C.R.I. Sit 814*. Mi4la4 scb ATTENTION OF Cr>rr Rasaareb 1 Oavtlaaaaat 544 Sitff. Industrial Hygiene Services: Plant Engineerings Plastics Maint. Services R. R. Langner, 607 Building R. W. Price, 824 Building R. J. Anderson, 761 Building row C-4W smarts uxa. *>w OOU 00484 ST00OO9S6 z. PROBLEM Industrial Hygiene was asked to evaluate the exposures of maintenance personnel to fibrous dust during the installation and removal of insulation from pipes and tanks. CONCLUSIONS 1. During the removal of asbestos insulation from an outdoor tank, breathing zone concentrations of asbestos fibers ranged from 2.0 to 6.7 fibers/ml. in this situation, with adequate ventilation available, the asbestos concentrations were within acceptable . levels. 2. Removal of asbestos insulation from equipment located indoors (or outdoors in confined areas) could easily result in asbestos levels exceeding the maximum allowable concentration of 10 fibers/ml. Respiratory protection is recommended for the men handling the asbestos insulation. If feasible, wetting down the insulation before removal is also recommended to help keep the dust levels to a minimum. 3. During the installation of fibrous glass insulation on an indoor tank, the levels of airborne glass fibers were relatively low ranging from 0.1 to 0.3 fibers/ml. Residual amounts of asbestos on the equipment and floor grating (from recently removed insulation) resulted in asbestos fiber concentrations ranging from 0.1 to 0.7 fibers/ml. DOW 00485 ST0000957 . 3 PRESENTATION OF DATA During the removal of asbestos insulation from an outdoor tank (339 Building), several breathing zone samples were collected to indicate the levels of exposure to asbestos fibers. The men were working at the top of the tank when the samples were taken. A relatively strong wind tended to carry any dust away from the men, though occasionally there was enough turbulence to create a dust cloud in the work area. Table 1 shows the result of four samples collected during the morning and afternoon. In this case, the asbestos fiber levels were within acceptable levels. However, without a strong wind or removing asbestos insulation indoors, the fiber concentrations would easily reach excessive levels. At 206 Building, several breathing zone samples of airborne dust were collected during the installation of glass fiber insulation. The samples were checked for asbestos fiber concentrations since asbestos insulation had recently been removed from the equipment. Some asbestos was evident on the equipment and also on the floor gratings at various levels in the building. The concentrations of glass fibers were also determined for comparitive purposes. Table 2 shews the results of the seven samples collected at several work sites in the building. The asbestos fiber concentrations in the work areas were within acceptable levels. The glass fiber concentrations were relatively low ranging from 0.1 to 0.3 fibers/ml. The air samples were collected on personal monitors mounted on the men's collar (37 mm diameter filter, 0.8 microm pore) at sample rates of about 2.0 liters/minute. The fiber concentrations were DOW 00486 ST0000958 4 determined by the Midland Division Microscopy Laboratory using the standard phase-contrast method for asbestos fiber analysis. OO^7 oOu STI&0959 TABLE 1 ASBESTOS FIBER CONCENTRATION DURING REMOVAL OF ASBESTOS INSULATION, TANK 6T4, 339 BUILDING SAMPLE I (Morning) 2 (Morning) 3 (Afternoon) 4 (Afternoon) AIR VOLUME SAMPLES (LITER) ASBESTOS CONCENTRATION FIBERS >5jx (FIBERS/ml) 40 2.25 32 3.75 18 1.99 14 6.71 OOU 0048S STOO 00960 TABLE 2 ASBESTOS AND GLASS FIBER CONCENTRATIONS DURING INSTALLATION OF GLASS FIBER INSULATION 206 BUILDING SAMPLE AIR VOLUME SAMPLES (l) FIBER CONCENTRATION . . (FIBERS/ml) ASBESTOS GLASS FIBERS 1 63.6 2 66.0 3 20.0 4 22.0 5 27.2 6 30,0 7 33.0 0.14 0.38 0.66 0.48 0.19 0.22 0.12 0 0.20 0.13 0.30 0.10 0.13 0.20 Sample I - man working below tank being insulated Samples 2*7 * men cutting glass fiber insulation and covering tank, (loose asbestos on tank and floor grating being kicked around) DOW 00489