NYC-WTC_000195194

NYC 9/11 Public Portal Document

secondary numeric criteria. Cleaning continued in the residential units and commercial spaces until primary clearance criteria were achieved. Some areas required three cleaning events.

This report provides information on the type of cleaning and sampling methods that were used, the results of the analytical analyses performed, and the conclusions that were made based on the information collected.

w 1.2 Identification of Contaminants of Potential Concern (COPC)

Under the auspices of the Interagency Indoor Air Task Force working group, a committee was formed to identify contaminants of potential concern (COPC) and associated health-based clearance criteria for the lower Manhattan clean-up program. Among other purposes, this initiative was intended to inform the selection of contaminants to monitor in the WTC Residential Confirmation Cleaning Study and Background Study and to provide a measure of cleaning effectiveness by establishing health-based clean-up goals for indoor air and settled dust. A draft of the COPC/Benchmarks Report prepared by EPA was peer reviewed on October 21-22, 2002. The final report is currently being completed. As such, the COPC identified for inclusion in the study reflect those contaminants cited in the peer review draft of the COPC/Benchmarks Report .*

The development of the COPC report began with an assessment of the indoor environment 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 PAH were identified, along with building materials such as asbestos and fibrous glass. Ambient air, indoor air, and indoor/outdoor bulk dust monitoring data were also reviewed. Data sources included EPA's ambient air and bulk dust/debris monitoring program (www.epa.gov/wtc), OSHA's air/dust monitoring data, and the NYCDOHMH/ATSDR indoor air pilot program. A concerted effort was also made to identify and review additional sources of WTC-related data from other governmental agencies (e.g., U.S. Geological Survey, NYC Department of Education) academic institutions, environmental organizations, and the private sector.

A semi-quantitative screening process was performed on the collected sampling data referenced above. Based on frequency of detection, concentration, and inherent toxicity, contaminants that exceeded health-based screening levels for ambient air were identified. Dioxin and PAH were added to the COPC list by this process. In addition, building constituents with carcinogenic effects (asbestos) or irritant effects (fibrous glass, alpha-quartz) that were consistently and significantly found in bulk debris and indoor dust samples were identified as COPC.’ Finally, lead was included based on a comparison of sampling data with existing regulatory standards. w Collectively, the resulting group of contaminants (asbestos, lead, dioxin, PAH, fibrous glass and alpha-quartz) are called "contaminants of potential concern" or COPC in this report. w w w ^U.S. Environmental Protection Agency. (September, 2002). World Trade Center Indoor Air Assessment: Selecting Contaminants of Concern and Setting Health-Based Benchmarks. A draft report. Peer review has been completed; final publication pending. Customarily referred to as the COPC/Benchmarks Report.

^NYCDOHMH, 2002. 5

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