Asbestos bulk sample analysis summary, 225 Liberty Street, 2001-2002

NYC 9/11 Public Portal Document

GPS Environmental Consultants, lnc.

A detailed description of each cleanup phase is located in appendix A.

4.0 HVAC Cleanup Activities

KASCO personnel performed the cleanup of the HVAC distribution system between the C levels and 22"d Floor. All KASCO personnel were given respirator fit tests and Pulmonary Function Tests prior to working at the site. Additionally, all personnel have been trained in environmental cleaning procedures. The procedures for cleaning are as follows:

HVAC Cleaning Procedures

(1) All supply registers and return air grills are removed and cleaned. (2) Prior to cleaning, the position of the balancing damper shall he marked. (3) All filtration devices are removed, inspected and replaced with new. (4) Access ports were installed to facilitate the cleaning process in accordance with SMACNA Standards (SMACNA Standards in Construction 1985). (5) All visible debris is removed from the supply duct system, return duct system, plenum filter compartment, blower fan and housing, and all other components in conformance with NADCA 1992-01 — National Standard, Mechanical Cleaning of Non-Porous Air Conveyance System Components. (6) Canvas flex duct to linear slot diffusers are removed and replaced. (7) Al] duct linings in the high pressure duct systems on the discharge side of the supply fans are coated to prevent shedding. The duct liner in the outdoor air intake duct system shall also be coated. (8) Register and grills shall be securely reinstalled and mechanical dampers returned to their original positions. (9) The system is checked to ensure functional operation in manner equivalent or exceeding operation prior to the cleaning process.

5.0 Project Monitoring, Air Sampling and Analysis

GPS Environmental personnel included NYS DOL certified project monitors and air sampling technicians who collected air samples and monitored the activities of all cleaning personnel to ensure compliance with state and city regulations. The project began on September 24, 2001 and is ongoing

GPS personnel collected background, work area preparation, during abatement and post abatement air samples in conjunction with the cleanup. Samples were analyzed using Phase Contrast Microscopy or Transmission Electron Microscopy. Wipe samples are also collected and analyzed prior to re-occupancy.

Merrill Lynch, World Financial Center, South Tower, 225 Liberty Street, New York, NY Page 4

NYC-WTC 000097300