NYC-WTC_000208376

NYC 9/11 Public Portal Document

Overall, when elevated air levels of fibers were found in lower Manhattan (in six areas) the additional analysis showed that the elevations were more likely due to cellulose, textiles, and other fibers rather than asbestos or fibrous glass. Upper respiratory tract irritation due to inhaled fibers has been reported in instances when fiber concentrations were far greater than any of the amounts found in the results of this investigation.

Table 2a Fibers in Air for 366 Broadway and the upper Manhattan Comparison Area (fibers per cubic centimeter of air)

366 Broadway* Comparison Area* Fibers in Air Common Outdoor Residence Residence Common Outdoor Residences Area #1 #2 Area Total Fibers <0.001 <0.001 <0.001 0.001 0.002 ■ 0.001 0.003 (PCM) Asbestos NA NA NA NA NA NA NA (TEM) SVF (SEM) NA NA NA NA 0.00004 0.00004 0.00009 *Results are maximum values found in location PCM = phase contrast microscopy TEM = transmission electron microscopy SEM = scanning electron microscopy NA = not analyzed SVF = synthetic vitreous fibers

Fibers in Settled Dust

Table 2b describes the sampling results for fibers in settled dust at your building. Low levels of asbestos were found in some settled dust samples in Lower Manhattan, primarily below Chambers Street. Polarized light microscopy (PLM), a method that can distinguish between fiber types, was used to determine the presence of synthetic vitreous fibers (SVF) and asbestos. If the presence of asbestos was found at levels of less than 1%, a more sensitive method (TEM methodology) was used to determine the presence of asbestos. Occasionally it was not possible to analyze the material by TEM methodology (e.g. not enough material present). The presence of SVF (primarily fiberglass) was identified in many of the samples collected in lower Manhattan. No SVF or asbestos was detected in the settled dust in comparison areas.

Although the airborne levels of asbestos and SVF did not present a health concern (see Conclusions/Recommendations), the presence of these materials in the settled dust in some locations indicates the need for continued frequent cleaning with HEPA vacuums and damp cloths/mops to reduce the potential for exposure.

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