DOH/DEP asbestos fact sheet draft, 105 Duane Street

NYC 9111 Public Portal Document

CVYATC ASSOCIATES INC. Ambient Air Sampling

To: Related Management Company Subject: Summary of Ambient Air Sampling to Date Re: Tribeca Tower From: Fred Burkhardt Date: December 11, 2001

The following is a brief summary of the observations, real-time monitoring, and ambient air sampling performed at Tribeca Tower to date. Apartment Visual Inspection ATC visually inspected 406 units for accumulated dust and/or debris consistent with material that from ATC's experience emanated from the collapse of the World Trade Center Buildings. Thirty-four units were inaccessible or the occupants refused access and were not inspected. Of the 406 units inspected, ATC did not observe any dust and/or debris accumulations that in ATC's opinion was consistent with widespread deposition of material that emanated from the collapse of the World Trade Center Buildings. However, ATC observed adjacent to open windows in four units, limited dust accumulations (no debris) although inconsistent with material that emanated from the collapse of the World Trade Center Buildings present nonetheless.

Asbestos Air Sampling via TEM ATC collected a total of 60 common area and 149 residential unit samples to ascertain the presence or absence of airborne asbestos. All samples were collected and analyzed in accordance with the AHERA Transmission Electron Microscopy (TEM) method as set forth at 40 CFR Part 763, Subpart E, Appendix A which provides resolution down to 0.5µ. structure size. Of the total 209 samples collected, a single asbestos structure was detectable on only two samples. In the absence of a specific ambient air standard, ATC has selected as a criteria for acceptable ambient air sample sets, the AHERA re-occupancy requirement following an asbestos abatement action of an average of less than 70 asbestos structures per square millimeter (<70 s/mm2) per sample set. This criteria has been selected because the AHERA requirement is the most stringent reoccupancy requirement available, and has been designed to be protective of children following an asbestos abatement project. Based upon analytical sample results for all samples recording levels well below the AHERA clearance requirement, it is ATC's opinion that the ambient air samples collected throughout the building are representative of the ambient conditions at the time of testing and that the areas tested meet an acceptable criterion for re-occupancy

NYC-WTC 000125922