Asbestos analysis results for 55 Broadway samples, 2002

NYC 9/11 Public Portal Document

DATA SUMMARY REPORT — 50 Broadway, New York, NY 10004

Ambient Group, Inc. performed a follow-up indoor environmental survey of 50 Broadway, New York, NY 10004. The survey was performed on May 1, 2002. The purpose of the survey was to determine levels of various air quality parameters, and to review the mechanical ventilation system operation and maintenance. The survey was conducted during normal business hours while the HVAC system units were in operation. Sampling was conducted on the 1st, 5th, 7th, 10th, 12th, 17th, 19th, 20th, 29th, and 33" floors in occupied areas near supply air diffusers. An outdoor air sample was also collected for comparison purposes. The samples were analyzed for airborne fibers, airborne asbestos, airborne metals and airborne mercury. The survey also included a visual inspection of the HVAC units on the floors listed above. The results of this survey indicate the following:

I. Indoor Air Quality Sampling

A. Airborne Asbestos (TEM) — Ten (10) indoor samples were collected in total. The sample locations were on the 33`x, 29th, 20th, 19th, 17", 12th, 10th, 7th, 5th and 1st floor. An outside air sample was also collected on the 7th Floor. All indoor sample locations were in occupied areas near supply air diffusers. Samples were collected for eight hours at 2 liters/minute and analyzed by Transmission Electron Microscope. All results were below Asbestos Hazard Emergency Response Act (AHERA) standard of 70 structures/mm2. Please refer to Table 1, insert and Appendix A for results and regulatory standards. Please refer to the floor plans in Appendix C and photographs in Appendix D for specific sample set-up and locations.

B. Airborne Fibers (PCM) — Ten (10) indoor samples were collected in total. The sample locations were on the 33'J, 29`h, 20th, 19th, 17th, 12th, 10th, 7th, 5th and 1st floor. An outside air sample was also collected on the 7th floor. All indoor sample locations were in occupied areas near supply air diffusers. Samples were collected for eight hours at 2 liters/minute and analyzed by Phase Contrast Microscope. All results were below Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.10 fibers/cc. Results were also below New York City re-occupancy standard of 0.01 fibers/cc. Please refer to Table 1, insert and Appendix A for results and regulatory standards. Please refer to the floor plans in Appendix C and photographs in Appendix D for specific sample set-up and locations.

Project: 220490 Page 1

NYC-WTC 000105539