NYC-WTC_000208373

NYC 9/11 Public Portal Document

Summary ofAsbestos Sampling Results Page 3 of 3 Address: 130 Water Street Date sampled: November 30, 200J

ASBESTOS DUST TEST RESULTS In general, the dust and debris samples were examined by two different laboratory methods for asbestos fibers. Polarized Light Microscopy (PLM) and Transmission Electron Microscopy (TEM). PLM is used to define asbestos containing material in dust and debris. A material is considered to be asbestos containing material if it contains more than 1% asbestos using the PLM method. The PLM method only counts the larger asbestos fibers. Therefore, if results by PLM were not greater than 1% asbestos, the sample was then analyzed by the TEM method that does count the smaller fibers. However, TEM analysis is not used for regulatory purposes for dust samples.

No asbestos fibers were found in the dust samples from outside, the common area or in the two residences by the PLM laboratory method. Further analysis by the TEM method detected asbestos in the common area dust at levels of less than 1%. The TEM method did not detect any asbestos fibers in the dust from outside or the two residences.

Fibrous materials in dust found by PLM analysis: Polarized Light Microscopy identifies asbestos fibers by shape and optical characteristics. Other fibers such as fabric (synthetics), paper (cellulose) and fiberglass may be identified in the analysis. The laboratory analyst counts the fibers present to give an estimate of fiber content. PLM is used for regulatory purposes for dust samples.

Results of Polarized Light Microscopy (PLM) testing of dust at 130 Water St, Nov 30, 2001 |Area Sampled Outside Common Residence 1 [Residence 2 Sample Numbers SA-C-24 VA-C-24 VA-Rl-24 A-R2-24

Asbestos fibers (%) None Detected None Detected None Detected None Detected

Asbestos in dust as determined by TEM analysis: TEM analysis was conducted on all dust samples that showed asbestos content by PLM as less than 1%. TEM analysis is very specific, can detect smaller fibers of asbestos and is subject to less interference. This analysis was done to confirm the PLM findings of no asbestos found. However, TEM analysis is not used for regulatory purposes for dust samples.

Results of Transmission Electron Microscopy (TEM) testing of dust at 130 Water St, Nov. 30, 2001 Area Sampled utside Common Residence 1 Residence 2 Sample Numbers A-C-24 VA-C-24 VA-Rl-24 VA-R2-24

Asbestos fibers (%) [one Detected < 1.0% None Detected None Detected

CITY_21MC100_010212468

NYC-WTC_000208375