Environmental assessment report, 100 Church Street, April 2002

NYC 9/11 Public Portal Document

Table 5b in Appendix A presents the results for lead wipe samples collected within boxes in the NYCLD space. According to ZAR’s cleaning contractor, Milro, all items such as files, papers, books, personal effects, etc. were cleaned in the fall of 2001. Therefore, these items were cleaned prior to placement in the boxes. All results were below the analytical detection limit.

Heating, Ventilation, Air Conditioning System

Fifty (50) lead wipe samples were collected and analyzed within the HVAC system serving the NYCLD and the Office of Mayor spaces. TRC collected the samples after ZAR’s initial duct cleaning contractor, G&G cleaned the HVAC. Samples were collected in the supply and return ductwork, air handling units serving the spaces, induction units and return air plenum. As can be seen from Tables 6a through 6f, twenty-seven (27) of the fifty (50) lead wipe samples collected in the HVAC system exceeded the HVAC post-cleaning target concentration of four hundred micrograms per square foot (400 ugTt").

In response to these results, ZAR retained the services of Branch, an abatement contractor who subcontracted the services of Cunningham and LAP, two National Air Duct Cleaning Association (NADCA) certified duct cleaning contractors. Together they re-cleaned and encapsulated the entire HVAC system serving the NYCLD space following NADCA cleaning protocols. The re­ cleaning of the HVAC system serving the NYCLD was successfully completed on March 20, 2002. TRC collected a second set of wipe samples after the re-cleaning. Results of post re­ cleaning lead wipe sampling are presented in Table 7b of Appendix A. Only one (1) sample associated with Fan No. 8 on the 2H‘ floor exceeded the post-cleaning target of less than 400 ug/ft^. The area was re-cleaned and re-sampled and found to be less than the analytical detection limit. Of the other forty five (45) samples taken, all were below the post cleaning target of 400 ug/ft^, and thirty were below the analytical detection limit.

Sampling Methodology Sampling and analysis for lead on surfaces was conducted utilizing specially manufactured sampling wipes. A known surface area (typically 1ft x 1ft) is wiped, and the wipe sample is submitted to the lab and analyzed.

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