Air sampling summary report, 400 Chambers Street, 2002

NYC 9/11 Public Portal Document

YATC ASSOCIATES I N C. Project Memorandum

Subject: Tribeca Park 400 Chambers Street Re: Ambient Air Sampling r `

To: Peter Hoyle Related Management From: Fred Burkhardt Date: November 23, 2001

On November 19, 2001, ATC collected one ambient air sample in the apartment listed below as well as one sample in five common hallways 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. Apartments sampled are identified in the following table.

Floor Apartments Floor Apartments Floor Apartments PH 20 9 28 19 Hallway 8 Hallway 27 18 7 26 17 N 6 25 16 5 24 15 4 23 Hallway 14 Hallway 3 Hallway 22 12 1 21 10 outside + 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 project.

Based upon analytical sample results for all samples recording levels 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. If you have any questions or require additional explaination of the information presented please do not hesitate to call me at 212-353-8280.

Thank You.

NYC-WTC 000102805