EPA interim final report on WTC background study, April 2003

NYC 9/11 Public Portal Document

World Trade Center Indoor Air Assessment: Selecting Contaminants of Potential Concern And Setting Health-Based Benchmarks

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 fi-om the collapse of the towers and associated fires, extended monitoring of the ambient air at and beyond the perimeter of the WTC site over the past year indicates that contaminant concentrations pose a low risk of long-term health effects. During this same time period, limited investigation of the indoor environment in residential dwellings has occurred [NYCDOH, 2002; Chatfield & Kominsky, 2001]. As the cleanup of the WTC site is coming to an end, governmental health and environmental agencies are directing resources to evaluate the indoor environment for the presence of pollutants that might pose long-term health risks to local residents. Selecting Contaminants of Potential Concern (COPCs) and setting health-based benchmarks will assist the Pilot Cleaning Effectiveness Initiative^ and inform the selection of contaminants in the Background Study’.

Selecting the Contaminants of Potential Concern (COPCs)

The assessment of the indoor environment began with a review of historical information on hazardous substances that have been associated with building fires and collapses [Wallace, 1990]. Many compounds, including combustion by-products such as dioxins and polycyclic aromatic hydrocarbons (PAHs) were identified for further investigation, along with building materials such as asbestos and fibrous glass. In addition, ambient air, indoor air, and indoor/outdoor bulk dust monitoring data were reviewed. Data sources included EPA’s ambient air and bulk dust/debris monitoring program (www.epa.gov/wtc), OSHA’s air/dust monitoring

' 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 Enviromnental Protection (NYCDEP).

’EPA is conducting a pilot program in an uncleaned/unoccupied building at 110 Liberty Street to determine the effectiveness of various cleaning methods for removing asbestos and other contaminants of potential concern from residential dwellings.

’Most if not all of the pollutants associated with the collapse of the World Trade Center were present in New York City's enviroiunent prior to September 11. To establish a baseline for the presence of these contaminants in affected residences, EPA will collect and analyze samples to look for some of these pollutants in apartments in parts of Manhattan that were not impacted. The Agency will use the data to determine pre-existing or "background" levels of these pollutants in interior spaces in New York City.

NYC-WTC_000145962