EPA interim final report on WTC background study, April 2003

NYC 9/11 Public Portal Document

buildings sampled were constructed roughly between 1892 and 1981.

EPA began the task of obtaining access to building common areas and residential units on June 14,2002 and continued through September 23,2002. As access agreements were signed and returned from volunteer participants, appointments were scheduled for sampling of the building. Sample collection activities were completed on September 25,2002.

3.3 Selection Criteria for Number of Buildings, Residences and Common Space Sampled The number of buildings, residences and common spaces samples were determined by what could practically be achieved to avoid impeding the project. There were no formal criteria established for selecting the number of buildings to be incorporated into the study or the number of residential dwellings and common spaces to be sampled within each building due to the difficulty in obtaining access and time constraints for conducting the Study.

The objective of the Study was to collect samples from at least three sites within each building: two or more residential units and one of the building common spaces. For the most part this objective was met, however in three instances only one common space and one apartment were sampled per building and in five buildings access was obtained to sample two residential units per building. Access could not be obtained to sample the common spaces of these five buildings.

3.4 Selection of Contaminants of Potential Concern Under the auspices of the EPA’s Interagency Indoor Air Task Force, a committee was formed to identify the COPCs and associated health-based benchmarks for the Indoor Air Residential Assistance - WTC Dust Cleanup Program. This committee drafted the "World Trade Center Indoor Air Assessment: Selecting Contaminants of Potential Concern and Setting Health-Based Benchmarks" report that was peer reviewed on October 21-22,2002. This report is currently being revised for finalization.

Among other purposes, this report identified the selection of contaminants for monitoring in the WTC Background Study and provided a measure of cleaning effectiveness by establishing health-based benchmarks and clean-up goals for indoor air and settled dust. As such, the COPCs identified for inclusion in the Study reflect those contaminants cited in the peer review draft of the aforementioned report.

The development of the COPC report began with an assessment of the indoor enviromnent by reviewing historical information on hazardous substances that have been associated with building fires and collapses. Many compounds, including combustion byproducts such as dioxins and PAHs were identified, along with building materials such as asbestos and fibrous glass. In addition, WORLD TRADE CENTER BACKGROUND STUDY 10

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