E-mails 2002 M. Gilsenan

NYC 9/11 Public Portal Document

Final Report 125 Cedar Street, NYC, NY

EXECUTIVE SUMMARY

ATC Associates Inc. (ATC) provided project monitoring, air sampling and management services for the interior dust clean-up activities for the unoccupied building located at 125 Cedar Street, New York, New York. Actual field operations were held from September 12, 2002, with the collection of background wipe samples through November 1, 2002 with the completion of post testing. Background wipe samples for settled dust were analyzed in accordance with the project specifications and the individual analytes were as follows: Lead, Mercury, Poly Aromatic Hydrocarbons, and Dioxin. Clean-up activities within the unoccupied building was conducted in accordance with generally accepted industry practices, as well as the Project specification issued by the New York City Department of Environmental Protection

Action Environmental, a New York State Department of Labor (NYSDOL) licensed asbestos abatement contractor, performed the cleaning services. ATC performed project monitoring, air sampling and management services for the interior dust clean-up activities including; review of contractor worker certification, Contractor oversight, daily collection and analysis of ambient and clearance air sampling.

Prior to the start of cleaning activities, ATC inspected that each area was under negative air flow to ensure compliance with the project Scope of Work Procedures. Negative air flow entailed the installation of negative air units within the apartments, however, because typical cleaning activities included cleaning all surfaces, the apartment units could not be sealed, hence negative pressure wasn't achievable or monitored. As the clean-up project progressed, ATC continuously monitored the Contractor's work practices, generated daily site logs, and collected ambient air samples in areas surrounding the abatement work areas. All ambient air samples collected during this project were less than 70 structures per cubic centimeter as specified, well below acceptable levels established by federal regulations (AHERA).

Once the Contractor completed cleaning activities from within all areas, in accordance with project Scope of Work Procedures, ATC, NYCDEP and EPA visually inspected each work area to ensure the areas were decontaminated to a level of no visible debris. Following this successful final visual inspection, ATC performed final air and wipe clearance sampling in accordance with project Scope of Work Procedures. Air clearance sampling entailed collection of fiberglass air samples, analyzed via NIOSH method 7400 "B" counting rules, crystalline silica, analyzed via NIOSH 7500, as well as an EPA modified Transmission Electron Microscopy (TEM) AHERA standard referred to as PCMe. All TEM air samples were analyzed by ATC's New York City laboratory, with all sample results satisfying the accepted final air clearance criteria of less than or equal to 0.0009 f/cc PCMe.

Clearance wipe sampling was performed consistent with generally accepted industrial hygiene practices. There were inherent limitations created by operational and work practice variability, variations in contaminant concentrations, and sampling and analytical accuracy.

ATC Project No. 15.22906.0002 Page 2

NYC-WTC 000162622