Asbestos sampling summary, 250 South End Avenue, Nov 2001

NYC 9/11 Public Portal Document

Summa/ of .asbestos Swnpling Results l'age 3 of 4 Address: 250 South End Date sampled. November 14, 2001

ASBETOS DUST TEST RESULTS

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.

Asbestos was found in low levels in the courtyard outside the building. DOH and City Department of Environmental Protection (DEP) inspected the building after the sampling was conducted to determine if further action was warranted. Additional testing and an assessment of the debris in the garden troughs in the courtyard indicated that it needed to be cleaned by an asbestos abatement contractor. The building owner hired a contractor and the debris was abated in accordance with DEP asbestos abatement regulations. Low levels of asbestos were also found in the dust on a window sill of the building. The concentration of asbestos found in this sample did not warrant the use of an asbestos abatement contractor since it was less than 1%. No asbestos fibers were found in the dust samples collected from the floor in the common area or 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 will count 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 250 South End Avenue, November 14, 2001 rea Sampled Outside Outside* I Common Residence 1 Residence 2 IResidence 3** Sample Numbers SA-C-2 SA-C-2B /A-C-2 A-R1-2 VA-R2-2 /A-R3-2

sbestos fibers (%) <I% 1.3 % done 4one one I% etected etected Detected * The outdoor courtyard was resampled on December to confirm the presence of asbestos. ** This sample was settled dust from a living room window sill. The other interior dust samples were from the floor.

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.

NYC-WTC 000121067