Environmental assessment report, 100 Church Street, April 2002

NYC 9/11 Public Portal Document

Fibers - NIOSH Sampling and Analytical Method 7400. Results were compared to the OSHA PEL for asbestos fibers of 0.1 fibers per cubic centimeter of air.

Ethanolamine - NIOSH Sampling and Analytical Method 2007. Results were compared to the OSHA PEL for Ethanolamine of 3 parts per million.

Representative sampling was conducted on each floor within the NYCLD space.

Because there is reason to believe that the fibers generated by the WTC collapse were small fibers, TEM analysis of air samples for asbestos was the analytical method used in this assessment to determine whether asbestos was present in the air. TEM is the state of the art analytical technique with the greatest analytical sensitivity to identify small asbestos fibers that can be missed by other analytical techniques, including Phase Contrast Microscopy (PCM).

Biological sampling was conducted in the cellar and subcellar areas. These areas were the only areas impacted by water intrusion as a result of power failure. Results of this sampling are presented in Appendix C and under separate cover in the March 8, 2002 report entitled “Microbiological Investigation of Subcellar and Cellar at 100 Church Street.”

Air sampling for fibers and ethanolamine (the active ingredient in the carpet mastic release agent) was conducted during carpet removal activities. Sampling was conducted to determine if carpet removal control procedures were effective in controlling potential exposures below United States Occupational Safety and Health Administration (OSHA) permissible exposure limits (PEL). Due to the quantity of data, the results of this sampling are presented under separate cover in the April 2, 2002 report entitled “Environmental Monitoring for Carpet Removal at 100 Church Street.” Any results for fiber air sampling by PCM that exceeded the OSHA PEL or New York City Department of Environmental (NYCDEP) clearance air standards for personal and area samples, respectively, were further analyzed by TEM to determine if the fibers present were asbestos.

All analytical work was performed by independent laboratories certified by the NYSDOH under ELAP.

3.6 Outside Air Quality Data

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