NYC-WTC_000199612

NYC 9/11 Public Portal Document

Summary of Asbestos Sampling Results Page 2 of A Address: 250 South End Date sampled: November J A, 200J

Results of Phase Contrast Microscopy (PCM) testing of 250 South End Avenue, November 14, 2001 Area Sampled Outside Common Residence 1 Residence 2

■ample Numbers A-Rl-2 A-0-2 A-C-2 A-R2-2

Concentration of Fibers in Air 0.003 0.005 <0.001 0.002 at this location (fZcc)* Concentration of Fibers in Air <0.001 to 0.001 <0.001 to 0.002 <0.001 to 0.003 <0.001 to 0.003 at background locations (f/cc) NYC Re-occupancy 0.01 0.01 0.01 0.01 Standard (f/cc)** * fZcc is fibers in each cubic centimeter (cc) of air. This is calculated from the number of fibers seen on the air filter and the volume of air pulled through the filter measured in cubic centimeters. ** New York City Department of Environmental Protection asbestos clearance criteria for post-abatement work (Rules of the City' of New York, Title 15, Chapter 1)

Asbestos in air as determined by TEM analysis: TEM analysis is very specific and can distinguish between asbestos and non-asbestos fibers, such as textiles, fiberglass, or cellulose. This analysis determines if the fibers seen in the PCM analysis are asbestos, or if they are some other material. TEM analysis was conducted on all air samples that showed more than 0.003 {/cc in the air by PCM analysis. No asbestos fibers were found in the TEM analysis of the air samples in your building where PCM levels exceeded 0.003 Ecc.^

Results of Transmission Electron Microscopy (TEM) testing of 250 South End Avenue, November 14, 2001 Area Sampled Common

Sample Numbers A-C-2 Concentration of Asbestos Fibers in Air at this location <0.001 (f/cc)* ___________________________________ Concentration of All Fibers in Air at background locations < 0.001 to 0.003 (fee)_________________________________________ NYC Re-occupancy Standard (f/cc) ** 0.01 * f/cc is fibers in each cubic centimeter (cc) of air. This is calculated from the number of fibers seen on the air filter and the volume of air pulled through the filter measured in cubic centimeters. ** New York City Department of Environmental Protection asbestos clearance criteria for post-abatement work (Rules of the City' of New York, Title 15, Chapter 1)

The TEM method employed here, NIOSH 7402, counts fibers of the same size as those detected by PCM analysis. Fibers reported here are greater than or equal to 5 microns in length and 0.25 microns in width.

CITY_21MC100_003034787

NYC-WTC_000199613