Law Department notice on WTC document preservation, Oct 2001

NYC 9/11 Public Portal Document

actions are necessaiy to prevent uncleaned sub-parts of the HVAC system from re-contaminating the system. When cleaning individual rooms, each air supply or return register should be sealed to prevent re-entrainment of toxicants into the HVAC system.

According to EPA officials, as of July 2003, 143 buildings had been cleaned, including 28 HVAC systems.

Non-Aggressive Sampling Does Not Provide Assurance Residents Will Not be Exposed to Potentially Harmful Levels of Asbestos

The non-aggressive sampling option available to residents does not provide assurances that residents will not be exposed to potentially harmful levels of asbestos. AHERA protocols for building clearance after abatement require aggressive sampling to re-entrain (stir) settled dust before air samples are taken. The modified aggressive option available to residents may not re-suspend asbestos particles clinging to surfaces within the residence.

Comprehensive Health Protection Would Also Include Workspaces

EPA, FEMA, and New York City implemented a cleaning and testing program for residences but not workspaces. Some have complained about this limitation, noting that a program of comprehensive health protection would address indoor contamination in workspaces. The EPA Region 2 Assistant Administrator for WTC Recovery Operations told us that EPA had discussed this issue with OSHA, and that workers or employers could contact OSHA if they had concerns about possible asbestos contamination in their work places. Further, EPA indicated that OSHA was prepared to address any workplace issues brought to its attention.

Cleanup Boundary Not Scientifically Developed

The northern boundary of the cleanup area (Canal Street), coincides with the initial exclusion zone developed on September 11. However, this boundary was not based on systematic and representative sampling to determine the likely outer boundary of WTC contamination. Several indoor sampling efforts were conducted after September 11, but none were designed to determine the geographic extent of WTC dust contamination. Consequently, it has not been determined whether buildings north of Canal Street or east of Lower Manhattan, in Brooklyn, were contaminated.

EPA officials told us that the Canal Street boundary represented a conservative one based on visual inspection of how far dust and debris from the collapse traveled aKwell as^their interpretation of various data, including images obtained by overhead flights. We also discussed the path of the dust and smoke plume with an Office of Research and Development researcher. He told us that his modeling demonstration as well as satellite images taken by the U.S. Geological Survey

52 Report No. 2003-P-00012

NYC-WTC_000145407