NYC-WTC_000164840

NYC 9/11 Public Portal Document

Indoor Air Assessment: Choosing Contaminants of Potential Concern And Setting Health-Based Benchmarks

DRAFT: 13 May 02 Introduction

Since September 11, 2001, the outdoor environment around the World Trade Center (WTC) site and nearby areas has been extensively monitored by a group of federal, state, and local agencies'. The agencies have taken samples of the air, dust, water, river sediments and drinking water and analyzed them for the presence of pollutants that might pose a health risk to response workers at the WTC site, office workers, and local residents. While some people may have experienced acute irritant and respiratory effects from the collapse of the towers and associated fires, extended monitoring of the ambient air over the past eight months indicates that contaminant concentrations pose a minimal risk of long-term health effects. As the cleanup of the WTC site is coming to an end, the agencies are directing attention to monitoring the indoor environment for the presence of pollutants that might pose long-term health risks to local residents.

The investigation of indoor air began with historical information on hazardous substances that have been found in past building fires and collapses. The list was reduced to those contaminants that might be found around the WTC site, because of what was known about the towers and an analysis of ambient air monitoring data that measured the frequency, concentration, and intrinsic toxicity of an extensive list of chemicals. The resulting group of contaminants are called “contaminants of potential concern” or COPCs in this report.

Selecting the Contaminants of Potential Concern (COPCs)

The list of hazardous substances that historically have been found after building fires and collapses is shown below, categorized according to whether they might be found around the WTC site or not [Wallace, 1990].

Substances Associated with WTC & Substances At Background Levels Found in Significant Concentrations or Consistently Below...... Asbestos Benzene Fibrous Glass PCBs Refractory Ceramic Fibers Chromium Silica Cadmium & Manganese Dioxin Mercury PAHs Particulate Matter Lead

' Agencies include the U.S. Environmental Protection Agency (EPA), Agency for Toxics and Disease Registry (ATSDR), New York State Department of Health (NYSDOH), New York City Department of Health (NYCDOH), Occupational Safety and Health Administration (OSHA), New York State Department of Environmental Conservation (NYSDEC) and New York City Department of Environmental Protection (NYCDEP).

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