NYC 9/11 Public Portal Document
(
October 26, 2001, Protocol for
Ambient and Indoor Sampling for Public Health Evaluations of
Residential Areas Near World Trade Center, New York, New York
I. Introduction
Prior to November 4, 2001, this sampling protocol was developed to assess potential exposures
to airborne and settled surface dust that entered residential areas following the collapse of the
World Trade Center (WTC) buildings. The collapse of the WTC buildings resulted in a large
number of residents being evacuated from their homes. Since the collapse, some residents have
not re-occupied their apartments/homes near the WTC. Many of these residents have either
visited to assess damage or to clean. Many have re-occupied their homes, and it is anticipated
that more residents will soon be moving back. To date, environmental sampling efforts have
focused on rescue/recovery areas (occupational); some sampling of commercial buildings to
ensure office worker safety; and ambient (outdoor) air sampling for asbestos in a number of
residential/commercial areas. Additional sampling is needed to assess possible WTC-related
contaminants in residential areas-both indoors and outside.
Surface dust and debris containing asbestos have been found in lower Manhattan. Asbestos has
been detected in personal air samples of rescue and recovery workers. In addition, low levels of
asbestos have been detected in air samples collected at the WTC perimeter. Crystalline silica
quartz has been detected in some of the 30 settled dust samples collected by the Centers for
Disease Control and Prevention’s National Institute of Occupational Safety and Health (NIOSH).
Although most samples contained less than 5%, some samples contained from 15-20%
crystalline silica quartz. Of the twelve personal air samples from the work site that have been
analyzed for respirable crystalline silica, no detectable levels were found.
Dust, bulk, and air samples (mostly on or near the work site), as well as surface runoff water,
river sediment, and river water have been analyzed for other contaminants, including metals,
volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), dioxins and
polychlorinated biphenyls (PCBs). The low levels of these contaminants that have been found
do not indicate an immediate need to conduct widespread environmental testing for them.
Materials in airborne dust that may be of more immediate health concem-especially to residents
who are returning to lower Manhattan-are those that can cause eye, nose, and throat irritation.
Materials that can be inhaled or respired from airborne dust may cause respiratory irritation and
exacerbation of pre-existing problems such as asthma, emphysema, and cardiopulmonary
disease. Analysis of WTC-related residential surface and airborne dust, both indoors and
outdoors, is to 1) respond to public concerns, 2) determine if residents are being exposed to
concentrations of materials that may be of public health concern; 3) determine whether areas
already cleaned (inside and outside environments) contain materials that may be of public health
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