Environmental assessment report, 100 Church Street, April 2002

NYC 9/11 Public Portal Document

dioxins. No PCBs were detected in any of the samples. Asbestos, lead and dioxins were detected in samples collected. As a result of these findings, carpets, computers, faxes, printers and copiers were replaced, air induction units were repainted and the NYCLD space and HVAC system were extensively re-cleaned. Subsequent to completion of these activities, TRC re-tested surfaces in the HVAC system. All samples were found to be less than applicable target post-cleaning standards. TRC is in the process of re-testing surfaces in the NYCLD space. All results received to date were found to be less than the applicable target post-cleaning standards.

• Based upon the sampling conducted to date and the evaluation of the data compared to applicable standards, guidelines and human health risk assessment protocols, TRC has determined that re-occupancy of the NYCLD space at 100 Church Street is recommended.

7.0 RECOMMENDATIONS Subsequent to re-occupancy, TRC recommends the following:

• Conduct on-going air monitoring within the NYCLD space on a routine basis. The intent of this on-going air monitoring is to confirm that the air quality within the NYCLD space is maintained and that changing conditions associated with the construction activities at the WTC do not adversely impact the NYCLD air quality. This program will continue until site activities which have the potential to generate emissions or concern cease or until analysis of data shows that continuance of the program is no longer necessary. On the same basis, the program may be modified to decrease the frequency of sampling events or target list, should data from the ongoing monitoring activities support such modification. The on-going air monitoring program will include air sampling for asbestos (TEM), total respirable dust, metals, carbon dioxide, carbon monoxide, temperature and humidity. During each sampling event, three interior sample locations will be selected for monitoring. Sample locations within the building will vary with each sampling event so that each floor will be sampled. Sample locations on a floor will vary between sampling events to provide a representation of the various functional areas (i.e. offices, cubicle spaces, interior spaces, etc.). The overall program will be reviewed monthly to determine if modification of the program is appropriate.

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