Addendum #2: Procedures for WTC dust in ventilation systems, 2002

NYC 9/11 Public Portal Document

ADDENDUM #2 World Trade Center Dust Cleaning Program Monitoring Contract Scope of Work

Evaluation Procedures to Determine the Presence of World Trade Center (WTC)-Related Dust and Debris in Residential Ventilation Systems in Lower Manhattan

1.0 SCOPE

The procedures contained in this document provide guidance for determining the presence of WTC-related dust in residential ventilation systems in Lower Manhattan. This document is solely concerned with determination of the presence of WTC-related dust in residential ventilation systems. Determining the exact nature of all hazardous air contaminants and contaminants other than airborne dust that may have been released during the WTC collapse and that may have potentially impacted ventilation systems operating at the time of the collapse is beyond the scope of this document.

This document provides general guidance to address the following with respect to residential ventilation systems impacted by WTC-related dust:

• Professional, health and Safety Requirements for Individuals performing the evaluations • Evaluation Procedures (Visual Assessment, Historical Assessment, and Sampling Procedures) • Post-Cleaning Visual Inspection Procedures

This document is limited in scope to evaluation of environmental conditions within the ventilation systems to determine whether they have been impacted by the WTC collapse. This document is not concerned with the following:

• Mechanical operation of the systems • Environmental conditions, contaminants, or other conditions within the systems that are not related to the WTC collapse • Recommendations and procedures that by their nature must be contaminant-specific

2.0 PURPOSE

The purpose of this document is to provide procedures for inspecting and evaluating residential ventilation systems in Lower Manhattan to determine if such systems have been impacted by airborne dust from the WTC collapse, and to provide guidelines for the qualifications of personnel accomplishing such inspection and evaluation.

WTC-related dust is generally considered to have common, consistent, and readily observable characteristics visually and tactilely differentiating it from common dust. WTC-related dust generally contains extremely fine particles similar in consistency to talcum powder, is light­ colored, contains pulverized concrete and/or gypsum wallboard, and may contain asbestos fibers.

Ventilation systems are reservoirs for environmental dust and dirt. Therefore, in some cases, it may not be possible to visually differentiate between WTC-related dust and environmental dust

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