Fiberglass and mineral air sampling results, Building 1, Oct 2001

NYC 9/11 Public Portal Document

I r DRAFT Settled Dust Sample Collection and Analyses:

Settled dust samples were collected from indoor floors by using a specialized vacuum cleaner. The outdoor samples were collected by scraping visibly-settled material into a container. XRD was used to analyze the crystalline mineral content of each sample. Results are reported as percent (%) of the specific mineral per weight of the dust sample.

Crystalline silica, calcite, port/lime, and gypsum were found in your building at levels above those found in the comparison areas. These materials are common components of building and road construction materials.

Please refer to the previous part of this report (flyer) for the limitations of this data, the possible symptoms of exposure, and recommendations on how to reduce your potential for exposure.

Explanation of Table 2: Fibers found in Air and Settled Dust in Your Building and the Comparison Areas

Air Sample Collection and Analyses: Air samples were collected for up to an eight-hour period using vacuum pumps to draw air past a filter that was suspended at the height of a person’s breathing level. All air samples were analyzed for total fibers using Phase Contrast Microscopy or PCM. If levels of total fibers were higher than those found in the comparison areas (0.003 fibers per cubic centimeter of air, or f/cc), the sample was re-analyzed using both Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). TEM analysis can distinguish asbestos from other fibers; SEM can distinguish fibrous glass from other fibers.

For an explanation of the asbestos results, please refer to the letter you received from us earlier this year that contained an enclosure titled: “Summary of Asbestos Sampling Results.” PCM results in one indoor location were higher than those found in the comparison area samples. Therefore, this sample was re-analyzed using TEM and SEM. Results of TEM showed asbestos less than 0.001 f/cc; results of SEM showed fibrous glass at 0.00016 f/cc. These levels are below those found in comparison area samples.

Settled Dust Sample Collection and Analyses: Settled dust samples were collected indoors and outdoors in the same manner described previously. At the laboratory, samples were analyzed for asbestos and fibrous glass fibers using Polarized Light Microscopy (PLM). PLM can distinguish asbestos from other fibers like asbestos by the appearance and the distinguishing color given off by each different type of fiber.

For an explanation of the asbestos results, please refer to the letter you received from us earlier this year that contained an enclosure titled: “Summary of Asbestos Sampling Results.” Indoor settled dust levels of 20% fibrous glass were found; none was detected in the comparison homes. Surface dust outside your building contained 22% fibrous

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