Environmental assessment report, 100 Church Street, April 2002

NYC 9/11 Public Portal Document

Post Re-cleaning Sampling TRC collected a second set of samples after NYCLD’s office space and the HVAC system were re-cleaned. These results are presented in Table 3. Table 3a presents the post-cleaning microvacuum samples collected in the NYCLD office area. Table 3b presents the post-cleaning microvacuum samples collected in the HVAC system.

All post-cleaning HVAC samples were found to be below the target post-cleaning individual sample and target geometric mean concentrations. Thirty-four (34) of forty-five (45) samples were found to be less than the analytical detection limit.

TRC is collecting at least three (3) microvacuum samples for asbestos per floor in the office space as re-cleaning is completed. TRC anticipates that re-cleaning of all five floors will be completed by the week of April 15, 2002 and anticipates that sample collection will be completed shortly thereafter. The results received to date are presented in Table 3 a.

Sampling methodology. Sampling and analysis of dust for asbestos was conducted utilizing microvacuum techniques to collect a sample for transmission electron microscopic (TEM) analysis to determine the number of asbestos structures in the dust collected per a measured surface area. This protocol utilizes a flexible tygon tube attached to the end of a sample filter cassette to microvacuum dust using a sampling pump. Microvacuumed dust is collected on the filter, cassette and tubing, which is then recovered for TEM analysis.

4.4.2 PCB Sampling and Results Eighteen (18) PCB wipe samples were collected and analyzed within the NYCLD space and HVAC system. The results are presented in Table 4 of Appendix A. All samples were below the analytical detection limit (less than 2.0 micrograms per 100 square centimeters). This means that the laboratory equipment and test method employed were unable to detect any PCBs in any of the wipe samples.

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