WTC environmental investigation report, Sep 2002

NYC 9/11 Public Portal Document

Final Technical Report of the Public Health Investigation Page 31 of 56 This section of the report will provide a more in-depth review of where the various materials were detected. In addition, the public health concerns potentially associated with these materials is also presented.

4. Discussion of Resuits

Settled surface dust samples obtained from lower Manhattan as part of this investigation contained materials consistent with debris from a building collapse. Both indoor and outdoor settled surface dust samples contained some amount of insulation material (asbestos, glass wool, and mineral wool), components of concrete (portlandite, calcite, and quartz), and components of other building materials (gypsum, mica, and halite). These materials were not present at the same levels in the four buildings above 59th Street sampled for comparison.

Asbestos levels in dust in the lower Manhattan area, ranging from <1% to 3.4%, were consistent with samples taken of outdoor material by EPA after the WTC collapse. SVF levels in the settled surface dust in lower Manhattan were higher than in the comparison areas above 59th Street, ranging from 1% to 72%. No data were available for SVF in lower Manhattan prior to this investigation. Analysis of archived dust samples collected after the WTC collapse by NIOSH, confirms the presence of SVF in bulk samples taken in lower Manhattan.

The minerals found in settled surface dust from residential buildings in lower Manhattan were consistent with minerals reported by the United States Geological Survey (USGS) for outdoor settled surface dust across lower Manhattan after the WTC collapse (9). Thirty-three dust, two concrete, and two steel insulation samples were analyzed by USGS, including two from an indoor area. Quartz, calcite, and gypsum were reported for all of these samples. Each of these was occasionally reported as a major constituent of the material, i.e., estimated at 20% or higher. Twenty-six of these samples contained mica, usually estimated as trace or less than 5% of the material. Portlandite was only noted in two samples at trace levels, including the one indoor sample analyzed.

1. Association of Asbestos and Synthetic Vitreous Fibers

Based upon the sampling results, it appears that SVF is likely to be found in settled surface dust whenever asbestos is detected in the settled surface dust. All of the six outdoor and five common areas that had asbestos in settled surface dust also had SVF in the settled surface dust (Table 9). Of the ten residences that contained asbestos in settled surface dust, a little more than half also contained SVF. However, this does not hold true in areas without asbestos, where the absence of asbestos does not indicate an absence of SVF. Of the eight outdoor areas without asbestos in the settled surface dust, three contained SVF. Similarly, SVF was found in approximately 25% of the common areas and in approximately 36% of the residences without asbestos in the dust. Although the presence of asbestos in the dust seems to correspond to SVF, the absence of asbestos does not predict or correspond to a presence or absence of SVF in settled surface

http://www.atsdr.cdc.gOv/asbestos/lowernianhattan/ResSamp_Sep2002_Text.html 07/18/2003 NYC-WTC_000178418