1

LOWER MANHATTAN TEST AND CLEAN PROGRAM 

Final Report 

November 2008 

Prepared by: 

United States Environmental Protection Agency, Region 2 

New York City Response and Recovery Operations 

290 Broadway 

New York, NY 10007-1866 
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ACKNOWLEDGEMENTS 

With technical assistance from staff members of: 

EMSL Analytical Inc. 

Northeast Analytical Inc. 

Shaw Environmental and Infrastructure Inc. 

Westat 

Weston Solutions Inc. 

WRS Infrastructure and Environment Inc. 
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Contents 

Acronyms and Abbreviations page 4 

Executive Summary page 5 

Section 1 Introduction page 7 

Section 2 Program Description page 14 

Section 3 Program Results page 20 

Section 4 Analyses of Lead Results page 23 

Section 5 Apartments or Buildings Tested in both 2002-2003 

and 2007-2008 page 31 

List of Figures page 34 

List of Tables page 35 

References page 36 
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Acronyms and Abbreviations 

A area of the site 

ATSDR Agency for Toxic Substances and Disease Registry

f/cc fibers/cubic centimeter 

COPC contaminants of potential concern

DOF Department of Finance 

EPIC Environmental Photographic Interpretation Center

FEMA Federal Emergency Management Agency 

HEPA high efficiency particulate air 

HPD Housing Preservation and Development Department 

HUD U.S. Department of Housing and Urban Development 

HVAC heating, ventilation and air conditioning

MMVF man made vitreous fiber 

NYCDEP New York City Department of Environmental Protection 

NYCDOF New York City Department of Finance

NSLAH National Survey of Lead and Allergens in Housing 

N total number of events 

ng/m2

 nanograms per square meter 

PAH polycyclic aromatic hydrocarbon 

PCMe phase contrast microscopy equivalent 

TEM transmission electron microscopy 

TEQ toxicity equivalent quotient 

UCL upper confidence limit

μg/ft2

 micrograms per square foot 

μg/m2

 micrograms per square meter 

USGS United States Geological Survey 

WTC World Trade Center 
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Executive Summary 

Introduction and Background

This report summarizes the results of the Lower Manhattan Test and Clean Program, a voluntary program,

offered to residents and building owners concerned about potential residual contamination in buildings

impacted by the collapse of the World Trade Center (WTC) towers. At the end of the World Trade Center

Expert Technical Review Panel process, EPA concluded that in the absence of a unique marker for WTC 

dust, the agency would be unable to detect a remaining pattern of contamination due to the collapse of the 

WTC. The widespread routine cleaning of indoor spaces and the fact that contaminants are found in every 

urban environment further confound any attempt to attribute contamination to the WTC collapse. The Test 

and Clean Program allowed residents and building owners to have the air and dust in their units tested for 

four contaminants associated with dust from the collapse of the World Trade Center, thus addressing 

concerns about the possibility of residual contamination in sampled areas. Therefore, the Lower Manhattan 

Test and Clean Program was not a random sampling program designed to allow EPA to make inferences 

about the lower Manhattan area. 

Overview of the Program

The voluntary Lower Manhattan Test and Clean Program covered the same area below Canal Street and 

west of Allen and Pike Streets that was targeted in EPA Region 2's 2002-2003 Indoor Air Residential 

Assistance Program. This program entirely encompasssed the geographic area where visible contamination

with WTC dust was confirmed by EPA’s Environmental Photographic Interpretation Center (EPIC). 

(Figure 1). 

Registration for the program occurred in January, February and March 2007. Two hundred seventy-three 

individual residents and a total of twenty-five residential and commercial buildings registered to 

participate. EPA offered a cleanup if a benchmark for any of the contaminants of potential concern was 

exceeded in any unit or building common area. EPA conducted surveys to determine whether exceedances 

were attributable to sources within or adjacent to the place of business or residence. EPA implemented this 

program utilizing FEMA Stafford Act funding. Sample results from this program were only designed to 

provide information about the levels of contaminants within the apartments or building common areas 

sampled. 

Program Results

One hundred and eighty-three (183) residential apartments and the common areas in 21 residential or 

commercial buildings were sampled. Some of the apartments and buildings that were registered were not

sampled because the owner or manager either decided not to participate or did not make or keep sampling 

appointments. Most of the samples had no detectable levels of contamination, with the exception of lead in 
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dust and total fibers in air. Eleven thousand one hundred and ninety-nine (11,199) air and dust samples 

were collected. Twenty-three (23) samples in 17 residential properties and 161 samples in the common 

areas of 16 buildings exceeded the benchmarks established for this program. Only lead in dust had a 

significant number of exceedances. One hundred and seventy-four (174) of the exceedances were lead in

dust, and the majority of these were associated with sources within the apartment or building. Ten (10) of 

the exceedances were asbestos (two in air and eight in dust). Four of the asbestos in dust exceedances were 

associated with existing sources within buildings. The remaining six exceedances (4 in dust – 2 in the 

basement air of a building) were not associated with existing sources within the buildings. A summary of 

the results is provided in Section 3 Table 3-1. 

A descriptive statistical analysis of the dust samples that contained lead was conducted. The descriptive 

statistical analyses describe the participating apartments and building common areas. Valid statistical 

inferences may not be made to any larger population of buildings because the participants are a selfselected group. When appropriate, comparisons were made with data from the National Survey of Lead 

and Allergens (NSLAH) conducted by the U.S. Department of Housing and Urban Development. EPA did 

not conduct a statistical analysis for dust samples with asbestos or the other substances because there were 

insufficient numbers of samples with detectable levels of asbestos (1% for both air and dust), MMVF (2% 

in dust) and PAH-TEQs (0% in dust). 

Some of the buildings and apartments participating in the Test and Clean Program had been either cleaned 

and tested or only tested in both the Indoor Air Residential Assistance and the Lower Manhattan Test and 

Clean programs. A summary of the results from both programs is provided in Section 3. The results are

provided for information only because the number of apartments and buildings involved is too small to 

draw definitive inferences. 
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Section 1 Introduction 

This report documents the final phase of the EPA response to the events of September 11, 2001. The 

Lower Manhattan Test and Clean Program offered participants a way to get information about potential 

residual contaminants from the collapse of the WTC present in their homes and buildings. 

Summary of Previous Sampling and Response Activities

EPA and many other agencies collected and analyzed environmental samples after the September 11, 2001 

attack on the WTC. Remote monitoring data was collected and analyzed by the United States Geological 

Survey (USGS, 2001), the Aerospace Corporation (2002), and EPA’s Environmental Photographic and 

Interpretation Center (US EPA, December 2005). The New York City Department of Environmental 

Protection (NYCDEP) conducted a building-by-building survey of the lower Manhattan buildings to 

determine the extent of external dust and debris contamination resulting from the collapse of the towers. 

The plume of dust from the collapse of the towers and subsequent fires were modeled by EPA (Gilliam, et 

al., 2005, Huber, et al., 2004). 

It is clear from these and other data, that the plumes from the collapse of the WTC and subsequent fires 

impacted the New York City metro area. The most heavily impacted area was approximately bounded on 

the north by Chambers Street and the Brooklyn Bridge approaches (Figure 1-1). This area was entirely 

contained within the area that was the subject of EPA Region 2's 2002-2003 Clean and Test Indoor Air 

Residential Assistance Program. 

Shortly after the 9/11 attack, concerns were raised about the impact of the attack on the indoor 

environment. The Ground Zero Task Force commissioned a survey of two residential buildings (Chatfield

& Kominsky, 2001). The buildings sampled were 45 Warren Street, four blocks north of Ground Zero 

(undamaged); and 250 South End Avenue, one block southwest of Ground Zero (damaged). The Warren 

Street building was considered to have been exposed to lower concentrations of dust than that at South End 

Avenue. The purpose of the survey was to assess the levels of polychlorinated biphenyls (PCBs), dioxins, 

furans, metals, and asbestos inside the buildings. Sampling was conducted on September 18, 2001. The

report concluded that concentrations of PCBs, dioxins, furans, and metals (excluding calcium) were 

generally low or below comparative background levels at both locations. Concentrations of asbestos found 

in dust samples and in the air inside the apartments were significantly elevated, and all of the indoor 

samples collected in the South End Avenue building exceeded ~0.05 S/cc PCMe. 

From November 4 through December 11, 2001, the New York City Department of Health and Mental 

Hygiene (NYCDOHMH) and the Agency for Toxic Substances and Disease Registry (ATSDR) collected 

environmental samples in and around 30 residential buildings in lower Manhattan, and comparison samples 
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Figure 1-1 Sampling Area and EPIC Confirmed Dust Zone 
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in four buildings above 59th Street (NYCDOHMH/ATSDR, 2002). The samples collected were analyzed 

for asbestos, synthetic vitreous fibers, mineral components of concrete (crystalline silica, calcite, and 

portlandite), and mineral components of building wallboard (gypsum, mica, and halite). Their 2002 report 

concluded that higher levels of asbestos, synthetic vitreous fibers (e.g., fiberglass), mineral components of 

concrete, and mineral components of building wallboard were found in settled surface dust in lower 

Manhattan residential areas when compared with comparison residential areas above 59th Street. 

NYCDOHMH and ATSDR recommended: 

1) Frequent cleaning with high efficiency particulate air (HEPA) vacuums and damp cloths/mops to 

reduce the potential for exposure; 

2) Additional monitoring of residential areas in lower Manhattan; 

3) An investigation to better define background levels specific to New York City for asbestos, 

synthetic vitreous fibers, mineral components of concrete, and mineral components of building 

wallboard; and, 

4) Residents in lower Manhattan who were concerned about potential WTC-related dust in their 

residences participate in EPA Region 2’s Indoor Air Residential Assistance Program. 

 

In February 2002, a multi-agency task force headed by EPA was formed to evaluate indoor environments 

for the presence of contaminants that might pose long-term health risks to residents. As part of this

evaluation, a task force subcommittee was established to identify contaminants of potential concern 

(COPC) that were likely to be associated with the WTC disaster and to establish health-based benchmarks 

for those contaminants during the planned (2002-2003) Indoor Residential Assistance Program in lower 

Manhattan. A systematic risk-based approach was used to select COPC. The goal was to identify those 

contaminants likely to be present within indoor environments at levels of health concern. The following 

chemicals were identified as COPC: dioxins, polycyclic aromatic hydrocarbons (PAH), lead, asbestos, 

fibrous glass, and crystalline silica. 

Risk-based benchmarks for these COPC were developed to be protective of long-term habitability of 

residential dwellings and were submitted for peer review (US EPA, 2003a). 

EPA also conducted a cleaning study to evaluate the performance of the cleaning methods recommended in

the NYCDOHMH and ATSDR report to ensure that the health-based benchmarks could be achieved by 

using them (US EPA, 2003c). EPA concluded the following: 

1) Observation of apparently WTC dust at that time was a good indicator that WTC contaminants 

were present, and the amount of such dust correlated with the level of contamination; 
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2) Concentrations of some contaminants in the WTC dust were elevated above health-based 

benchmarks; 

3) Use of a standard cleaning method of vacuuming and wet wiping significantly reduced levels of 

WTC-related contamination with each cleaning event and was successful in reducing 

concentrations to levels below health-based benchmarks (in some cases, 2 or 3 cleanings were 

necessary); 

4) Asbestos in air is a good indicator of whether additional cleaning is needed; and 

5) Standard HVAC cleaning methods reduced the concentrations of WTC contaminants in HVAC 

systems. 

Concurrently, EPA also conducted a “Background Study” to determine levels of selected contaminants in 

fourteen residential buildings (north of 77th Street in Manhattan) not directly impacted by the airborne dust 

plume that emanated from the WTC site (US EPA, 2003b). EPA sampled 25 residential units and nine 

common areas within the 14 buildings. The contaminants studied included: asbestos, lead, dioxins, 

polycyclic aromatic hydrocarbons (PAH), fibrous glass, crystalline silica, calcite, gypsum, and portlandite. 

The data collected from this study provided estimates of background concentrations for compounds that 

were identified as COPC related to the WTC collapse. The estimates were shown to be consistent with 

other background studies and historical data, where such comparison data were available. 

Beginning in 2002, residents of lower Manhattan, who lived below Canal Street, were provided a choice of 

services. Residents could choose to have their residences professionally cleaned, followed by confirmatory 

testing, or they could choose to have their homes tested. Owners and managers of residential buildings and 

boards of cooperatives and condominiums could also have their building's common areas cleaned and/or 

tested and the HVAC system evaluated and cleaned, as necessary. The common areas cleaned and/or 

tested included areas such as the building lobby, hallways, stairways, and elevator interiors. Certain other 

common areas, including laundry rooms, utility rooms, compactor rooms and elevator shafts, were cleaned 

and/or tested as needed. 

Between September 2002 and May 2003, residences were cleaned using standard cleanup methods: using 

HEPA-filtered vacuums and wet wiping all horizontal hard surfaces (i.e., floors, ceilings, ledges, trims, 

furnishings, appliances, equipment, etc.). Vertical and soft surfaces were HEPA vacuumed twice. 

Depending upon the size of the residence, from three to five air samples were collected and analyzed for 

asbestos by using transmission electron microscopy (TEM) and phase contrast microscopy (PCM). In a 

subset of the residences, pre and post-cleanup dust wipe samples were collected (e.g., from floors, walls, 

and furniture) and analyzed for dioxin, mercury, lead, and 21 other metals. A total of 4,167 apartments in 

454 buildings and 793 common areas in 144 buildings were sampled for asbestos in air. A total of 28,702 
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valid sample results were analyzed; 22,497 from residential units, and 6,205 from common areas within 

residential buildings (e.g., hallways, laundry rooms). 

The number of asbestos samples that exceeded the health-based benchmarks for airborne asbestos was very 

small, about 0.4% of the samples analyzed for asbestos. In those residences and common spaces where the 

benchmark was exceeded, the cleanup program was successful in achieving the health-based benchmark for

asbestos after the first cleaning approximately 99% of the time. Re-cleaning was offered when benchmarks 

were exceeded. An analysis of the location of asbestos exceedances did not demonstrate a spatial pattern of 

exceedances relative to WTC proximity. Apparent groups of asbestos exceedances could be explained by 

the location in the sampled buildings and the variability in the number of samples that were collected from 

each building. When EPA compared the frequency of detection from samples collected in the cleanup 

program with the frequency of detection for samples collected in the background study, we found that they 

were similar. There was a detection rate of 2% in lower Manhattan and 5% in upper Manhattan. The 

minimum concentrations from both areas were identical, while the maximum detected concentration in 

lower Manhattan was higher than the maximum detected concentration in upper Manhattan. Although the 

maximum detected concentrations were not similar between the two areas, the percentage of samples that

exceeded the health-based criteria was similar, with 0.5% in lower Manhattan and 0.0% (no exceedances)

in upper Manhattan. The mean values appear to be indistinguishable from background values. 

Wipe samples were collected from 263 apartments in 156 buildings. Approximately 14% of the precleanup samples exceeded the 25 μg/ft2

 U.S. Department of Housing and Urban Development screening 

level for lead. There were very few exceedances of the health-based screening values measured for any of 

the other 22 metals. The 627 μg/m2

 screening value for antimony was exceeded in two pre-cleanup 

samples (0.1% of all samples); the maximum measured value was 1,180 μg/m2. The 157 μg/m2 screening 

value for mercury was exceeded in five pre-cleanup samples (0.4% of all samples). Only eight of the 1,535 

(approximately 0.5%) of the combined samples (i.e., test only, and clean and test) exceeded the healthbased benchmark for residential dust dioxin loading of 2 ng/m2

. The percentage of apartments that 

exceeded the lead health-based benchmark was greater than the percentages of apartments that had 

exceedances for other metals, mercury and dioxin. The frequency of detection, the maximum detected 

concentration, and the percentage of samples that exceeded the risk-based criteria were higher in the dust 

cleanup program in lower Manhattan when compared with the results from the background study in upper 

Manhattan. The clearest relationship found was between lead concentrations and age of building, 

suggesting lead based paint as a cause for high lead measurements in lower Manhattan. Proximity to the 

WTC and floor of the building seemed to be, at best, weakly related to measured levels of lead. The level 

in lower Manhattan was consistent, however, with data from HUD on mixed age housing stock in the 

northeast United States. 
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World Trade Center Expert Technical Review Panel

In March 2004, EPA convened an expert technical review panel to provide individual guidance and 

assistance to the Agency in its use of available exposure and health surveillance databases and registries to 

characterize any remaining exposures and risks, identify unmet public health needs, and individually 

recommend steps to further minimize the risks associated with the aftermath of the WTC attack. 

The WTC Expert Technical Review Panel (WTC Panel) members met periodically in open meetings to 

interact with EPA and the public about plans to monitor for the presence of WTC dust in indoor 

environments and to individually suggest additional measures that could be undertaken by EPA and others 

to evaluate the dispersion of the plume and the geographic extent of environmental impact from the 

collapse of the WTC towers. 

The WTC Panel members were charged, in part, with reviewing data from post-cleaning verification 

sampling to be done by EPA in the residential areas included in EPA Region 2's 2002-2003 Indoor Air 

Residential Assistance Program to verify that recontamination had not occurred from central heating and 

air conditioning systems. With the assistance of Westat, a contractor in the field of statistics, EPA

developed a sampling plan to evaluate whether apartments previously cleaned in the Assistance Program 

had become recontaminated. The plan proposed by EPA was debated by the individual panel members, 

and most panel members thought that an alternate study to test for “contamination” rather than 

"recontamination" should be conducted. 

The WTC Panel members also were charged with assessing the use of asbestos as a surrogate in 

determining risk for other contaminants. Using a peer review contract, EPA solicited comment from other 

external experts on this issue, and these experts provided a report that was shared with the WTC Panel

members. These external experts generally supported the use of asbestos as a surrogate, but they 

encouraged the concurrent testing for lead. Some individual members of the WTC Panel, however, did not 

believe that asbestos was an appropriate surrogate in determining risk for other contaminants. 

Other areas not specified in the WTC Panel members’ charge were also addressed by individual panel 

members as part of the discussions relating to assessing WTC-related contamination. These discussions led 

EPA to the concept that a WTC signature exists in dust. Sampling to determine the presence of the WTC

signature, as well as the levels of contaminants of potential concern (COPC), would serve as the basis for 

determining the extent of WTC collapse contamination in indoor environments. The premise was that a 

signature could be developed for both the dust generated by the collapse and particulate matter generated 

by the fires which burned into December of 2001. Unfortunately, EPA was not able to establish with 

certainty a WTC signature. EPA prepared a Final Report on the World Trade Center Dust Screening 

Method Study, which summarized efforts to investigate the validity of the collapse plume signature 
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concept, was prepared by EPA and submitted for peer review. A peer review of this document concluded

that, “EPA has not made the case that its proposed analytical method can reliably discriminate background 

dust from dust contaminated with WTC residue,” and that “[t]he proposed method has not demonstrated the 

utility of slag wool as a successful signature constituent.” In consideration of these comments EPA 

announced in November 2005 its plan to move forward with a sampling plan that did not depend on a 

signature. Subsequent to the December 13, 2005 WTC Panel meeting, EPA further evaluated both the peer

review and panel comments. EPA also conducted additional work to assist in answering questions that 

arose while considering the comments and discussed this work with panel members Paul Lioy, Morton 

Lippmann, and Gregory Meeker. A response to the peer review comments, summaries of the additional 

work performed by EPA, and an expanded statistical analysis of the study’s data have since been 

completed. The overall variability observed in the inter-lab data and the demonstrated possibility of

observing high levels of slag wool at sites not affected by the WTC collapse raise significant questions 

concerning the ability to use slag wool measurements generated with the current method as a tool for 

screening a sampled location for the presence of WTC related contamination. 

Lower Manhattan Test and Clean Program

At the end of the WTC Panel process EPA concluded that in the absence of a unique marker for WTC dust,

the agency would be unable to detect a remaining pattern of contamination due to the collapse of the WTC. 

The widespread cleaning of indoor environments, many known to have been impacted by WTC dust, and 

the sources of contamination in the urban environment further confound any attempt to attribute 

contamination to the WTC collapse. The Test and Clean Program, offered in the absence of a marker for 

WTC dust, covered the areas south of Canal Street and west of Allen and Pike Streets, allowed residents 

and building owners to have the air and dust in their units tested for four contaminants that remained of 

concern and are associated with dust from the collapse of the World Trade Center. Where analysis of dust 

and air samples found elevated levels of any of four contaminants of concern – asbestos, man-made 

vitreous fibers such as fiberglass, lead, and polycyclic aromatic hydrocarbons – the services of a 

professional cleaning service were offered. The Agency opened a registration period in January 2007, 

began testing of interior spaces in June 2007, completed testing in June 2008, and completed cleaning in 

September 2008. 
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Section 2 Program Description 

Eligibility

Individuals who owned or rented their apartments and the owners, boards of cooperatives or condominiums 

and managers of residential or commercial buildings located in Manhattan south of Canal Street and west 

of Allen and Pike Streets were eligible to register. Buildings that were not cleaned after the collapse of the 

WTC, were currently uninhabited, and slated for demolition; and buildings constructed or reconstructed

after May 2002 (when the cleanup effort at the WTC site was completed) were not eligible. 

The registration period for the Test and Clean Program opened on January 16, 2007, and closed March 30, 

2007. Registrants had to return an access agreement by April 30, 2007. 

Public outreach to the community eligible for the program was extensive. Seven newspapers in Lower 

Manhattan circulated 584,000 copies of the advertisement for the Lower Manhattan Test and Clean 

program, and 8,000 flyers were distributed door-to-door for Lower Manhattan residents and buildings. The 

EPA attended community board meetings to answer questions about the Lower Manhattan Test and Clean 

program and met with residents in various large apartment buildings in the area. EPA implemented this 

effort utilizing FEMA funding that had been earmarked for this program. In total, 25 whole buildings and 

273 residential units registered and were eligible for the program. The program began in June 2007 and 

was complete with the last cleaning occurring in September 2008. 

All buildings and units tested had a number of characteristics recorded to allow examination of potential 

relationships between results and the characteristics of the units and common areas sampled. Building and 

unit characteristics that may be relevant are described below. A “unit” generally denotes a reasonably well 

defined section of a floor that will be different for each building and building type. For example, a unit 

within a building could be an apartment or a common area such as a corridor leading to multiple apartments 

or offices. 

Two sets of dust samples were taken within each unit: (1) three or more samples at locations where dustrelated exposures are likely to occur, such as on elevated horizontal surfaces (e.g., desk or table tops) and 

floors; and (2) three or more samples at locations where WTC dust may have accumulated but would not 

have frequently been cleaned, such as on top of cabinets. The first sets of samples are termed “accessible” 

samples, and the second sets are “infrequently accessed” samples. Samples from these two types of 

locations were taken by wipes and microvacs. These samples yielded results in load (weight or fibers per 

unit area) and were compared with the benchmarks described in the COPC section, Table 1. 

Wipe samples were analyzed for the COPC lead and polycyclic aromatic hydrocarbons (PAH), and 

microvac samples were analyzed for the COPC asbestos and man-made vitreous fibers (MMVF). Wipe and 
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microvac samples were taken in proximate locations so that for each location sampled within a unit, there 

were measurements of the four COPC. Indoor air samples were also collected in units and common areas 

at locations proximate to the locations where accessible dust samples were collected. Indoor air samples 

were analyzed for asbestos and for the presence of MMVF. 

The analytical results from both the air samples and the dust samples were used to determine whether or 

not a cleaning was offered to the occupant or owner of the unit being tested. Details on the criteria used to 

make these decisions are described in the section entitled “Decision Criteria for Activities Following

Sampling.” 

Specific building and space characteristics were gathered from the occupants of residences and building 

representatives in order to aid in understanding the results. The information gathered is listed in 

Attachment 1. 

Source attribution was a critical factor in determining whether to retest after cleaning. For example, if lead 

exceedances triggered a cleanup, a source survey was conducted. Where it was found that a potential 

source of the exceedance was within the building or adjacent to the building, no further cleaning or resampling to demonstrate clearance was offered. 

Contaminants of Potential Concern (COPC)

The COPC measured in this program were asbestos, MMVF, PAH and lead. Dust samples were obtained 

from both accessible (e.g., floors) and infrequently accessed (e.g., behind a bookshelf) areas. EPA’s 

preferred approach to establishing cleanup benchmarks is risk-based. PAH and lead are both toxic via 

ingestion. Risk-based benchmarks for lead and PAH in settled dust (accessible areas) were developed 

because the primary route of exposure for these two contaminants in the indoor environment is incidental 

ingestion associated with direct contact with settled dust. The risk-based benchmarks for PAH and lead in 

settled dust for accessible areas are listed in Table 2-1. 

Infrequently accessed areas were sampled to investigate the presence of contaminant reservoirs, or places 

where dust can accumulate and stay over long periods of time. The potential for direct exposure from 

infrequently accessed areas is low; thus benchmarks for these areas are not specifically risk-based. Rather, 

contaminant reservoirs pose the potential to contaminate accessible areas. Accordingly, the benchmarks for 

infrequently accessed areas were developed to minimize this potential. The infrequently accessed area 

benchmarks for the four COPC are also listed in Table 2-1. 

Asbestos and MMVF toxicity occurs primarily from inhalation exposure. Therefore, the risk from asbestos 

and MMVF exposure is best determined by measuring concentrations in air. The risk-based benchmarks for
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asbestos and MMVF in indoor air are listed in Table 2-1. Contaminant values are considered 

“exceedances” if they are greater than the respective benchmark, but not if they are equal to the benchmark.

Table 2-1 Cleanup Benchmarks 

Contaminant Dust Benchmark 

(accessible) 

Dust Benchmark 

(infrequently accessed) 

Air Benchmark 

Asbestos 5,000 s/cm2 50,000 s/cm2 .0009 s/cc 

Man-Made Vitreous 

Fibers 

5,000 f/cm2 50,000 f/cm2 .01 f/cc 

Lead 40 μg/ft2

 400 μg/ft2 NA 

PAH 150 μg/m2

 1,500 μg/m2 NA 

NA = Not Applicable 

Asbestos is made up of long, thin fibers and structures that are strong and heat-resistant. It has been used in

thousands of products (such as building materials and heat-resistant fabrics). Inhaled asbestos is associated 

with three major diseases: asbestosis, lung cancer, and mesothelioma. 

The risk-based clearance level for asbestos is 0.0009 structures per cubic centimeter (s/cc) in air. The level 

of risk associated with this benchmark is very low based on a person being exposed every day for 30 years. 

The asbestos benchmark for air is based on long structures(> 5 μ). 

The benchmarks for asbestos in settled dust are not risk-based because there is no scientific consensus on 

how to determine if these fibers will ever be inhaled. The dust benchmarks are based on all structures 

equal to or greater than 0.5 μ; it was based on a weight of evidence approach that considered 1) measured 

background values, 2) an experience standard developed by experts in the asbestos identification field, and 

3) benchmarks developed for other sites. The benchmark for asbestos in accessible areas is 5,000 structures 

per square centimeter (s/cm2) and 50,000 s/cm2 for infrequently accessed areas. The use of a benchmark 

for infrequently accessed areas is intended to minimize the potential for recontamination of accessible 

areas. 

Man-made vitreous fibers (MMVF) are a class of insulating materials used widely in residential and 

industrial settings; they are made primarily from glass, rock, slag or clay. The fibrous particles have long, 

thin geometry, like asbestos, and can irritate the respiratory tract. MMVF's can also be a skin irritant. 

Man-made vitreous fiber (MMVF) toxicity occurs primarily from inhalation exposure. The health-based 

clearance level for MMVF in air is 0.010 fibers per cubic centimeter (f/cc). The standards are intended to 
17

protect individuals from hazards associated with inhaling MMVF. The benchmark for MMVF in settled 

dust is not risk-based, and was developed with consideration given to both its toxicity and background

levels relative to asbestos. The benchmark for MMVF in accessible areas is 5,000 fibers per square 

centimeters (f/cm2

), and 50,000 f/cm2 for infrequently accessed areas. The use of a benchmark for 

infrequently accessed areas is intended to minimize the potential for recontamination of accessible areas. 

Lead is a toxic metal that was used for many years in products found in and around our homes. The 

primary source of lead exposure is deteriorating lead-based paint. Many homes built before 1978 contain 

lead-based paint. Soil can pick up lead from exterior paint, or may contain lead from vehicle emissions of 

leaded gasoline, even though it is no longer in use. Household dust may contain lead from deteriorating 

lead-based paint or from soil tracked into a home. Children six years old and under are most at risk,

because their nervous systems are not fully developed and they are prone to greater exposure as a result of 

mouthing activity. 

The risk-based benchmark for lead in settled dust is based on the federal Department of Housing and Urban 

Development standard of 40 micrograms per square foot (μg/ft2

) for accessible floor space and 400 μg/ft2

for infrequently accessed areas, such as window troughs. These standards are also used to clear indoor 

spaces after lead abatement work. Registrants were eligible for cleaning if the sampling results exceed 

these standards. The standards are intended to protect children from hazards associated with leadcontaining dust in the indoor environment. 

Polycyclic aromatic hydrocarbons (PAH) are a group of over 100 different chemicals that are formed 

during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or 

charbroiled meat. PAH are produced by many combustion sources and enter the air mostly as releases 

from burning coal, automobile exhaust, volcanoes and forest fires. In the indoor environment, PAH can

even be produced when you cook. The approximately 28,000 building fires that occur in NYC each year 

are also sources of PAH. Two PAH results are derived from testing; the individual PAH concentrations 

and the total PAH toxicity equivalent. The total PAH toxicity equivalent consists of nine individual PAH 

concentrations (1-Methylnaphthalene, 2,6-Dimethylnaphthalene, 2-Methylnaphthalene, Acenaphthene,, 

Acenaphthylene, Anthracene, Benzo[a]anthracene, Benzo[a]pyrene, Benzo[b]fluoranthene) converted to a 

standard unit of exposure, and then added together as a measure of the cumulative effect of the PAH. The 

value of the total PAH toxicity equivalent is then compared with the benchmark. 

The EPA health-based benchmark for PAH in accessible areas is 150 micrograms per square meter (μg/m2). 

The level of risk associated with this benchmark is very low based on the assumption of daily exposure

over 30 years. The benchmark for infrequently accessed areas is 1500 μg/m2. The benchmark for 

infrequently accessed areas is intended to minimize the potential for recontamination of accessible areas. 
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Sampling Methods

Air 

Sampling for asbestos and man-made vitreous fibers (MMVF) in air was performed by drawing a measured 

volume of air across a filter. The asbestos samples were analyzed using an electron microscope; the MMVF 

samples were analyzed using an optical microscope. In each case the filter was examined and the number

of fibers in a measured area counted. Problems can arise when too many dust particles were captured by the 

filter. The filter viewing area becomes obscured (i.e. overloaded) which interferes with the ability of the 

technicians examining the sample under the microscope to separate or identify individual fibers. Samples 

where this occurred or where the sample could not be analyzed for other reasons were listed as “Not 

Analyzed/Invalid.” 

Dust 

Dust samples for lead and PAH were collected by wiping a piece of soft paper over a surface, such as a

floor or wall. Dust samples for MMVF and asbestos were collected by a vacuuming technique referred to 

as microvac. 

Within individual units and building common areas, dust was collected from two types of areas, accessible 

and infrequently accessed. An accessible area is an area where people can be readily exposed to the dust, 

which include floors, tables and countertops. An infrequently accessed area is an area where people are not 

often exposed to the dust, which include the tops of bookshelves and under or behind refrigerators. 

Analytical Methods 

Air 

Asbestos 40 CFR Part 763 (Asbestos Hazard Emergency Response Act [AHERA]/PCMe) 

Fibers NIOSH 7400 (confirmed with Scanning Electron Microscope (SEM) if f/cc > .009) 

Dust 

Asbestos ASTM D 5755-03 

MMVF ASTM D 5755-03 (SEM) 

PAH EPA Method SW-846 8270D 

Metal Lead EPA Method SW-846 6010C 

Decision Criteria for Activities Following Sampling

The sampling results provided data that formed the basis for deciding whether to offer a cleaning of the 

unit, common area and the HVAC in the building being sampled, and whether to conduct any additional 

sampling within a unit or common areas of a building. Where COPC exceeded benchmarks, a cleanup was 

offered to the owner or occupants of those units or buildings. However, source attribution was a critical 

factor in determining whether to retest after cleaning and in discussions with the owner or occupant to 

determine whether an EPA cleanup would be useful and accepted. A source survey was conducted where 
19

exceedances were found. In those instances where peeling or flaking lead paint was noted, EPA suggested 

that the building management or apartment owners conduct remediations If the exceedance was due to a 

source within the building or adjacent to the building, no re-sampling after cleaning to demonstrate 

clearance was offered. 

The criteria used to decide whether to clean an apartment or common area was, as noted above, the 

occurrence of an exceedance of any individual benchmark. In deciding what, if any, additional cleaning 

should be offered in buildings, EPA used a statistical measure called the 95% Upper Confidence Limit 

based on the mean contaminant level for accessible areas, infrequently accessed areas, or air samples in 

common areas. A UCL is a measure of uncertainty commonly used in scientific studies that estimates 

uncertainty in a given set of data caused by sampling methods, measurement and other sources of 

variability. The 95% UCL defines a value that will be exceeded by the true mean approximately 5% of the 

time in repeated sampling. The 95% UCL is commonly employed in EPA hazardous site assessments to 

provide a conservative upper bound estimate on the average site-wide contaminant level. The UCL was 

used in the decision process as follows: If the 95% UCL for the estimated building mean in common areas 

exceeds the benchmark value for a COPC, then this was considered to provide support for the decision to 

offer to clean the whole building. Separate analyses were conducted for air samples, and accessible and 

infrequently accessed areas, and each was compared with its own benchmarks. EPA considered the source

of contamination, the HVAC configurations and the distribution of contaminant in determining what 

building components to clean. 
20

Section 3 Program Results 

One hundred and eighty-three (183) residential apartments and the common areas in twenty one residential 

or commercial buildings were sampled. Eleven thousand one hundred and ninety nine (11, 199) air and 

dust samples were collected, including duplicate samples collected for quality assurance purposes. Twenty 

three (23) samples in 17 residential properties and 161 samples in the common areas of sixteen buildings 

exceeded the benchmarks established for this program. A summary of the results is provided in Table 3-1. 

Only lead in dust had a significant number of exceedances, and the only exceedances found that resulted in 

a 95% UCL above benchmarks were for lead in dust. One hundred and seventy four of the exceedances 

were lead in dust. One hundred fifty two of the exceedances were in common areas of buildings. The 

majority of the lead exceedances were associated with sources within the apartment or building. 

Where there were exceedances of the benchmark, EPA contacted the resident or owner’s representative; 

verbally informed the individual of the exceedance and offered to perform a lead survey to determine 

whether there were sources of the contaminant of concern within the residence or building. After 

conducting a source survey, EPA provided a report to each resident or owner’s representative. The report 

contained the sampling results, source survey and information from NYCDOHMH and EPA describing 

how to deal with lead paint hazards, the primary source of lead contamination. EPA offered to clean all of 

the affected areas. In two buildings, building management decided to remediate deteriorated paint.. EPA 

contractors surveyed 15 apartments and 16 buildings. Lead paint was present in 13 apartments and 16 

buildings. 

Ten of the exceedances were asbestos (two in air and eight in dust). Nine of the exceedances were in 

common areas of buildings. ). Four of the asbestos in dust exceedances in two of the buildings were 

associated with existing sources within buildings. The remaining six exceedances (4 in dust – 2 in the 

basement air of a building) were not associated with existing sources within the buildings. A summary of 

the results is provided in Section 3 Table 3-1. 

Aside from lead in dust only total fibers in air were detected on a regular basis. All samples which 

approached the benchmark for MMVF in air were also analyzed by SEM. None of the samples analyzed 

by SEM had any MMVF fibers. This is consistent with the low incidence of detection of MMVF in dust. 

Only 58 of 3027 dust samples had detectable levels of MMVF. 

EPA cleaned 16 apartments, one apartment declined cleaning. EPA cleaned some or all common areas in 

14 buildings. As noted above building management decided to perform remediations in the other two 

buildings. In no instance was it considered necessary to clean HVAC systems. 
21

Table 3-1 Summary of Sampling Results 

Pollutant Matrix Area 

Property 

Type Samples 

NonDetects Detects Min Max Units NA/ 

Overloads Exceedances 

 

Asbestos Air Accessible Apartment 991 988 3 0.00034 0.0004 S/cc 0 0 

 Whole 

Building 

1103 992 11 0.00036 0.0043 S/cc 100 2 

 Dust Accessible Apartment 712 707 5 2590 18,100 S/cm2

0 1 

 Whole 

Building 

852 844 7 2470 61,800 S/cm2

1 2 

 Infrequently 

Accessed 

Apartment 790 782 8 2590 32,400 S/cm20 0 

 Whole 

Building 

685 662 23 2470 1,030,000 S/cm2

0 5 

MMVF PCM Air Accessible Apartment 991 3 988 0.0007 0.018 Fibers/cc 0 0 

 Whole 

Building 

1092 17 1060 0.0006 0.0087 Fibers/cc 15 0 

MMVF SEM Air Accessible Apartment 22 22 0 0.0001 0.0003 Fibers/cc 0 0 

 Whole 

Building 

0 Fibers/cc 

 Dust Accessible Apartment 706 699 7 15.9 254.4 f/cm2

0 0 

 Whole 

Building 

841 827 14 15.9 254.4 f/cm20 0 

 Infrequently 

Accessed 

Apartment 784 778 6 15.9 190.8 f/cm20 0 

 Whole 

Building 

674 643 31 15.9 508.8 f/cm20 0 

Lead Dust Accessible Apartment 712 159 552 0 507 μg/ft2

1 11 

 Whole 

Building 

841 100 741 0 21,100 μg/ft20 77 

 Infrequently 

Accessed 

Apartment 789 41 747 0 8820 μg/ft2

1 11 

 Whole 

Building 

674 7 667 0 102,000 μg/ft20 75 

PAH - TEQ Dust Accessible Apartment 706 705 0 69.3 69.3 μg/m21 0 

(Toxicity 

Equivalency) 

 Whole 

Building 

841 840 1 69.3 146 μg/m20 0 

 Infrequently 

Accessed 

Apartment 784 780 3 69.3 201 μg/m2

1 0 

 Whole 

Building 

674 664 9 69.3 2820 μg/m2

1 0 

Multiple analyses were performed on air and dust samples for asbestos and MMVF; therefore, the 

total number of results reported exceeds the total samples collected. The results above include those

from 985 duplicate samples collected for quality assurance purposes. 
22

Table 3-2 Summary of COPC Survey Results 

ID Property Square Feet EPA Cleaned COPC Survey Pos Neg Analyte(s)- Matrix 

Apt 1549 Yes Positive Result Lead-Dust 

Apt 864 Yes Positive Result Lead-Dust 

Apt 1165 Yes Positive Result Lead-Dust 

Apt 1450 Yes Positive Result Lead-Dust 

Apt 1387 Yes Positive Result Lead-Dust 

Apt 2013 Yes Positive Result Lead-Dust 

Apt 1737 Yes Positive Result Lead-Dust 

Apt 1508 Declined cleaning Not Applicable Lead-Dust

Apt 1317 Yes Positive Result Lead-Dust 

Apt 1008 Yes Positive Result Lead-Dust 

Apt 2025 Yes Positive Result Lead-Dust 

Apt 1072 Yes Positive Result Lead-Dust 

Apt 1250 Yes Positive Result Lead-Dust 

Apt 2000 Yes Negative Result Asbestos Dust 

Apt 1880 Yes Positive Result Lead-Dust 

Apt 934 Yes Negative Result Lead-Dust 

Apt 564 Yes Negative Result Lead-Dust 

Bldg 13500 Yes Positive Result Lead-Dust 

Bldg 21000 Yes Positive Result Lead-Dust 

Bldg 85000 Yes Positive Result Lead-Dust 

Bldg 18000 Yes Positive Result Lead-Dust 

Bldg 18000 Yes Positive Result Lead-Dust 

Bldg 70000 Yes Positive Result Lead-Dust 

Bldg 230000 Yes Both COPC Positive 

Result 

Asbestos-Lead-Dust 

Bldg 168000 Yes Positive Result Lead-Dust 

Bldg 200000 Declined cleaning Positive Result Lead-Dust 

Bldg 10480 Yes Positive Result Lead-Dust 

Bldg 12000 Yes Positive Result Lead-Dust 

Bldg 8000 Yes Positive Result Lead-Dust 

Bldg 120000 Yes Positive Result Lead-Dust 

Bldg 140000 Yes Both COPC Positive 

Results

Asbestos-Lead-Dust 

Bldg 450000 Yes Positive Lead 

Negative Asbestos 

Asbestos-Lead-Dust 

Asbestos -Air 

Bldg 125000 Declined cleaning Positive Result Lead-Dust 
23

Section 4 Analyses of Lead Results

Lead was the only COPC where there were a sufficient number of detectable sample results to conduct a 

statistical analysis. This section presents the analyses of the prevalence of dust lead exceedances. The 

analysis of lead results does not include duplicate samples collected for quality assurance purposes. . 

Table 4-1 presents the number of the participating properties by the following selected characteristics: 

 Use of the units (residential apartments vs. whole building common areas) 

 Year of construction of the units (after 1978, 1960-1977, 1940-1959, 1920-1939, and before 

1920). The self reported construction year data was checked against data in the NYC DOF 

and HPD databases provided by EPA. When there were discrepancies, the DOF and HPD 

data was considered more accurate and replaced the self-reported values. 

 Distance from WTC in feet (<1000, 1000-2000, 2000-3000, and 3000-4000) 

A higher percentage of whole building properties (76%) had dust with lead levels exceeding benchmarks 

than residential properties (8%). Apartments and whole buildings built before 1920 had the highest percent 

of properties with at least one measurement over the dust lead exceedance (49%). None of the buildings 

built between 1940 and 1977 had any measurements over the exceedance and only 3% of buildings built 

since 1978 did. A comparison of the present data with NSLAH is included in Table 4-1. The percentages 

are comparable, even though the NSLAH definition of a dust lead hazard is different from an exceedance. 

In NSLAH, a housing unit has a dust lead hazard if any of the dust lead measurements on floors is greater 

than or equal to 40 μg/ft2 or if any of the measurements on window sills is greater than or equal to 250 

μg/ft2. 

In Table 4-1, the percent of exceedances decreases slightly as the distance from WTC increases, up to 3000 

feet, then increases to 26%. This pattern is due to an uneven distribution of building ages in the different 

distance categories, especially the older age categories. Thirty-one percent (31%) of the 75 buildings 

within 1499 feet of the WTC were built before 1940; 26% of the 105 buildings between 1500 and 2999 feet 

of the WTC were built before 1940; and 68% of the 19 buildings more than 2999 feet from the WTC were 

built before 1940. A logistic regression of exceedances on building age and distance to WTC was 

conducted to confirm that this effect is due to building age. In this model, building age is a highly

significant predictor of exceedance with p< 0.0001 and odds ratio 1.05. Each year of age increases the 

probability of exceedance by 5%. Distance to WTC is not a significant predictor with p=0.53 and odds 

ratio 1.0. The probability of exceedance is unrelated to the distance from WTC. 
24

Table 4-1. Prevalence of dust lead exceedances in participating housing units by selected 

characteristics 

Characteristics 

All 

Properties 

(N) 

No. of 

properties 

with dust 

lead 

exceedance 

% of 

properties 

with dust 

lead 

exceedance 

NSLAH: 

% of housing 

units with 

dust lead 

hazards 

Total participating properties 204 31 15 

Use: 

Residential apartments 183 15 8 16 

Whole building 21 16 76 NA 

Construction year: 

>1978 97 3 3 2 

1960-1977 38 0 0 8 

1940-1959 5 0 0 18 

1920-1939 27 10 37 

before 1920 37 18 49 

41* 

Distance from WTC (ft): 

NA 

<1499 75 14 19 

1500-1999 41 5 12 

2000-2999 64 7 11 

≥3000 19 5 26 

Undefined 5 0 0 

Use by Distance from WTC (ft): 

Residential apartments 

<1500 64 6 9 

1500-1999 38 3 8 

2000-2999 60 3 5 

≥3000 16 3 19 

Undefined 5 0 0 

Whole building 

<1500 11 8 73 

≥1500 10 8 80 

* Refers to “Before 1939” 
25

Figure 4-2 presents the number of participating properties by Use, Construction Year, and Distance from 

WTC. The number of units in each category that exceeded are shown in red and marked above each bar. 

8 8

3

3

3

6

5

7

5

11

3

18

10

0

0

3

16

15

0

20

40

60

80

100

120

140

160

180

200

Residential apartments

Whole building

Construction year:

> 1978

1 96 0-19771 940-19591 920-1939

before 1 920

Distance from

WTC (ft):

< 1 000

1 000-15 001 500-20002000-3000

> 3000

Use by

Distance from

WTC (ft):

Residential apartments

< 15 00

1 500-19992000-2999

Whole building

< 15 00

Number of HU

Dust lead loading exceedance

Dust lead loading not over exceedance

Figure 4-2. Number of participating properties by Use, Construction Year, and Distance from WTC 

and number of dust lead exceedances 

Table 4-2 presents the prevalence of dust lead exceedances by sampling Matrix, Sub_location, and 

Area_surface for residential housing units. These variables are defined as following. 

There are two categories of sampling matrix, accessible and infrequently accessed. An accessible area is 

defined as an area where people are readily exposed to the dust such as floors, tables and countertops. An 

infrequently accessed area is defined as an area where people are not easily exposed to the dust such as the 

tops of bookshelves and under or behind refrigerators. 

Definitions of Sub_Location and Area_Surface are different for residential apartments and whole buildings. 

For residential housing units, Sub_Location categories include areas of the home such as entry, kitchen, 

living room, bedroom, and other rooms. Within residential housing units, the variable Area_Surface 

descriptions were sorted into two subcategories including floor (carpet, tile floor, doormat, hardwood floor, 
26

area rug), and surfaces other than floor (drape, top of cabinet, wall, wood, top of bookshelf, top of wall 

unit, shelf, top of large appliances, top of media center, etc). This separation of floors from surfaces other 

than floor was done because floors tend to accumulate dust both by deposition from the air and tracking 

from the outside and people are easily exposed to dust on this surface. 

Table 4-2. Prevalence of dust lead exceedance in residential housing units by Matrix, Sub_Location, 

and Area_Surface 

Characteristics 

All 

participating 

residential 

units (N) 

No. of units 

with dust lead 

exceedance 

% of units 

with dust lead 

exceedance 

NSLAH: 

% units with 

dust lead 

above HUD 

Rule (1) 

Matrix: 

Accessible 183 9 5 6 

Sub_Location 

Entry 90 2 2 

Kitchen 183 4 2 1 

Living room 157 1 1 1 

Bedroom 106 1 1 1 

Other rooms 55 1 2 2 

Area surface 

Floors 181 9 5 6 

Surfaces other than floors 183 0 0 

Matrix: 

Infrequently accessed 183 9 5 14 

Sub_Location 

Entry 13 1 8 

Kitchen 144 1 1 5 

Living room 173 4 2 5 

Bedroom 167 2 1 3 

Other rooms 64 2 3 3 

Area surface 

Floors 164 2 1 

Surfaces other than floors 179 8 5 14 

(1) HUD Lead Safe Housing Rule standards are 40 μg/ft2 on floors and 250 μg/ft2 on window sills. These 

locations are used here as approximations for “accessible” and “infrequently accessed” locations, 

respectively. 

In accessible areas, different rooms had similar percentages over the exceedance (1% for living rooms and 

bedrooms to 2% for entries, kitchens, and other rooms), while inaccessible areas in entries were more likely 

to have measurements over the exceedance (8%) compared to inaccessible areas in other rooms. For 
27

accessible areas, floors were more likely to be over the exceedance level (5% compared to 0% for surfaces 

other than floors). For infrequently accessed areas, surfaces other than floors were more likely to be over 

the exceedance (5% compared to 1% for floors). 

Also presented in Table 4-2 are the estimated national percentages of homes with dust lead levels above the 

HUD Lead Safe Housing Rule standards, 40 μg/ft2 on floors and 250 μg/ft2 on window sills, from NSLAH. 

These locations are used here as approximations for “accessible” and “infrequently accessed” locations, 

respectively. While the standards/exceedances and definitions of the surfaces do not match, they may be 

considered to be similar, allowing rough comparisons. 

For whole buildings, Sub_Location includes hallways at different floor, stairwells at different floor,

lobby/reception areas, and other areas. The variable Area_Surface was grouped into two categories, floors 

(floor, tile, carpet) and surfaces other than floor (bookshelf, wall, ceiling, top of bookshelf, behind large 

furniture, light fixture, metal behind liftgate, exit sign, etc.). Table 4-3 presents the prevalence of dust lead 

exceedances by sampling Matrix, Sub_location, and Area_Surface for whole buildings. A greater 

proportion of stairwells were over the exceedance level (58%) compared to hallways and lobbies (50% and 

46%, respectively), while other areas had a smaller proportion over the exceedance level (40%). For 

accessible areas, floors were more likely to be over the exceedance level (67%) compared to surfaces other 

than floors (24%); however, for infrequently accessed areas, floors were less likely to be over the 

exceedance level (14%, compared to 71% of other surfaces). 

 
28

Table 4-3 Prevalence of dust lead exceedance in whole building units by Matrix, Sub_Location, and 

Area_Surface 

Characteristics 

All 

participating 

whole 

buildings (N) 

No. of whole 

buildings with 

dust lead 

exceedance 

% of whole 

buildings with 

dust lead 

exceedance 

Matrix: 

Accessible 21 14 67 

Sub_Location 

Stairwells 12 7 58 

Hallways 14 7 50 

Lobbies 13 6 46 

Other areas 10 4 40 

Area surface 

Floors 21 14 67 

Surfaces other than floors 21 5 24 

Matrix: 

Infrequently accessed 21 15 71 

Sub_Location 

Stairwells 13 6 46 

Hallways 13 9 69 

Lobbies 13 3 23 

Other areas 10 5 50 

Area surface 

Floors 14 2 14 

Surfaces other than floors 21 15 71 

The relationship between prevalence of housing units with lead exceedances and the number of days since 

last cleaning was investigated. Six cleaning frequencies were tabulated; daily, every other day, weekly, 

every other week, monthly, and whenever. Corresponding days since last cleaning were derived as half of 

the frequency in general as: 0, 1, 4, 7, 15, and unspecified, respectively. Table 4-4a displays the number of 

exceedances by Matrix and days since last cleaning.

Unexpectedly, when more recent that cleaning was reported in general, the unit was more likely to have

dust lead loadings over the exceedances for both accessible and infrequently accessed areas. This result 

may be due to a similar confounding effect from building age that as was observed for the distance from 

WTC in Table 4-1. Dust lead samples were collected from accessible areas in 23 apartments and whole 
29

buildings reported by the owners/residents to have been cleaned daily. Nine of these 23 apartments and 

whole buildings had dust lead exceedances and all were built before 1940. However the relative 

percentages of old apartments and buildings (built before 1940) in other cleaning frequency categories are 

lower than this daily cleaning frequency group, which is in turn decreases the chance of having dust lead 

exceedances in these other categories. 

Table 4-4a. Prevalence of dust lead exceedances in participating properties by matrix and days since 

last cleaning 

Days since last cleaning 

All 

participating 

properties 

(N) 

No. of 

properties 

with dust lead 

exceedance 

% of 

properties 

with dust 

lead 

exceedance 

Accessible: 204 23 11 

0 23 9 39 

1 14 3 21 

4 86 4 5 

7 43 3 7 

15 21 1 5 

Unspecified 17 3 18 

Infrequently accessed: 204 24 12 

0 23 10 44 

1 14 1 7 

4 86 6 7 

7 43 4 9 

15 21 0 0 

Unspecified 17 3 18 

In addition, 120 of the participants reported that they had a professional cleaning after 9/11 and provided 

the date of the cleaning. This tabulation is presented as Table 4-4b. 

Date of professional cleaning does not seem to be related to the proportion of residential housing units with 

dust lead loadings over the exceedance levels for either accessible or infrequently accessed areas. 
30

Table 4-4b. Prevalence of dust lead exceedances in participating properties by matrix and date of 

professional cleaning 

Date of professional cleaning 

All 

participating 

properties 

(N) 

No. of 

properties 

with dust lead 

exceedance 

% of 

properties 

with dust 

lead 

exceedance 

Accessible: 204 23 11 

September-December 2001 28 3 11 

January-June 2002 15 1 7 

July-December 2002 8 0 0 

January 2003 and later 16 2 13 

Unknown 89 9 10 

No professional cleaning 48 8 17 

Infrequently accessed: 204 24 12 

September-December 2001 28 5 18 

January-June 2002 15 1 7 

July-December 2002 8 1 13 

January 2003 and later 16 2 13 

Unknown 89 7 8 

No professional cleaning 48 8 17 

 

The correlation between dust lead loading and lead based paint inspection were investigated at the unit 

level. However the small sample sizes (n=31) prevented this analysis from yielding meaningful results. 
31

Section 5 Apartments or Buildings Tested in both 2002-

2003 and 2007-2008 

Below is a summary of results for apartments or buildings that participated in both the 2002-2003 and 

2007-2008 EPA clean up programs. The tables only compare asbestos in air and lead in dust as they were 

the analytes common to both efforts. Neither effort was a random sampling program; thus the results 

cannot be used to make inferences about the area. However, the presence of lead exceedances and lack of 

asbestos exceedances in the 2007-2008 program are consistent with prevalence of lead in paint and the 

scarcity of asbestos in dust. 

Table 5-1 Lead in Apartments 2002-2003 compared to 2007-2008 

Note: Results from 2002-2003 program include pre- and post-cleaning sampling. 

Index 2002-

2003 # 

of 

Sample

s 

2002-

2003 # of 

Detects 

2002-

2003 # 

of 

Exceed

s 

2002-

2003 

Max 

Exceed

s 

2207-

2008 # 

of 

Sample

s 

2207-

2008 # 

of 

Detects 

2207-

2008 # 

of 

Exceeds 

2207-

2008 

Max 

Exceeds 

732 8 2 0 7 6 0

1358 8 8 0 7 7 0

1839 5 5 0 11 11 1 8820

4846 8 7 0 7 6 0

4871 8 8 0 7 7 1 91.4

4907 6 6 0 7 7 0

6094 7 7 0 7 6 0

6663 7 7 0 11 8 0

6822 7 7 0 11 10 0

7249 6 6 0 7 7 0
32

Table 5-2 Air Asbestos in Apartments 2002-2003 compared to 2007-2008 

Note: Results from 2002-2003 program include aggressive and modified aggressive air sampling 

procedures.

Index 2002-

2003 # 

of 

Samples 

2002-

2003 # 

of 

Detects 

2002-

2003 # of 

Overloads 

2002-

2003 # 

of 

Exceeds 

2002-

2003 

Max 

Exceeds 

2207-

2008 # 

of 

Samples 

2207-

2008 # 

of 

Detects 

2207-

2008 # 

of 

Exceeds

2207-

2008 

Max 

Exceeds 

62 3 5

9 6 6

61 3 5

73 5 3 6

76 5 5

25 5 5

52 3 5

8 9 6

20 5 6

26 5 6

1 5 6

5 5 1 6

14 5 5

53 6 5

18 5 6

66 5 5

59 5 5

12 5 5

37 5 5

32 10 5 5 0.0129 6

33 5 5

23 4 6

4 4 6

22 6 6

11 5 6

24 6 5

35 6 5

31 5 5

36 5 6

54 5 5

44 5 6

84 5 5

15 6 6

28 5 6

16 5 6

56 6 6

78 3 6

6 5 5

57 5 6

75 4 6
33

34 6 5

80 10 2 5

70 5 6

67 5 5

68 10 1 1 0.0028 5

55 3 5

46 5 5

81 5 5

45 5 5

71 5 5

83 5 5

21 6 6

17 5 5

7 5 3

19 5 5

2 6 5

60 6 5

Total 302 7 5 6 0.0157 307 0 0 0

Table 5-3 Asbestos in Building Common Areas 2002-2003 compared to 2007-2008 

Index 2002-

2003 # 

of 

Samples

2002-

2003 # 

of 

Detects 

2002-

2003 # of 

Overloads 

2002-

2003 # 

of 

Exceeds 

2002-

2003 

Max 

Exceeds 

2207-

2008 # 

of 

Samples 

2207-

2008 # 

of 

Detects 

2207-

2008 # of 

Overloads 

2207-

2008 # 

of 

Exceeds 

2207-

2008 

Max 

Exceeds 

3 75 84 4 

2 94 1 131 

1 28 2 94 1 

Total 197 2 1 0 0 309 1 4 0 0 
34

List of Figures 

Figure 1-1 Sampling Area and EPIC confirmed dust zone 

Figure 4-2 Number of participating properties by Use, Construction Year, and Distance from 

WTC and number of dust lead exceedances 
35

List of Tables 

Table 2-1 Clean up benchmarks 

Table 3-1 Summary of results 

Table 3-2 Summary of COPC results for Apartments or Buildings 

Table 4-1 Prevalence of dust lead exceedances in participating housing units by selected 

characteristics 

Table 4-2 Prevalence of dust lead exceedance in residential housing units by Matrix, 

Sub_Location, and Area_Surface 

Table 4-3 Prevalence of dust lead exceedance in whole building units by Matrix, 

Sub_Location, and Area_Surface 

Table 4-4a Prevalence of dust lead exceedances in units by matrix and days since last 

cleaning 

Table 4-4b Prevalence of dust lead exceedances in units by matrix and date of professional 

cleaning 

Table 5-1 Lead in Apartments 2002-2003 compared to 2007-2008 

Table 5-2 Asbestos in Apartments 2002-2003 compared to 2007-2008 

Table 5-3 Asbestos in Building Common Areas 2002-2003 compared to 2007-2008 
36

 References 

WTC Residential Dust Cleanup Program 

http://www.epa.gov/wtc/finalreport/

EPIC Report 

http://www.epa.gov/wtc/panel/pdfs/WTC5_WTC_Report_TextOnly_December_2005.pdf

http://www.epa.gov/wtc/panel/pdfs/WTC5_WTC_Report_FiguresOnly_Decmber_2005.pdf

COPC Report 

http://www.epa.gov/wtc/copc_study.htm

Sampling Plan 

http://www.epa.gov/wtc/panel/pdfs/lower-manhatten-indoor-test-and-clean-program-plandecember2006.pdf

Quality Assurance Project Plan 

http://www.epa.gov/wtc/testandclean/qappfor_test_and_clean.html
37

Attachment 1. Descriptive data collected for residences and buildings. 

ID 

Entry_ID_Number 

Last_Name 

First_Name 

Property_Street_Address 

Floor 

Other_space_descriptor 

Apt_No 

Property_or_Unit 

Contact_Comment 

Date_of_Inspection 

Inspector_Last_Name 

Inspector_First_Name 

Inspection_Comment 

Year_Built 

Building_type 

Use_of_Space 

Number_Rooms_Floors 

Square_Feet 

Prof_Cleaned_after_collapse 

Renovated_since_collapse 

No_Windows 

Type_of_Windows 

Condition_of_Windows 

No_Wall_Window_HVAC_Units 

No_Wall_Window_Units_replaced 

No_Wall_Window_Units_cleaned 

Carpet_Present 

Carpet_replaced_since_collapse 

Unit_Cleaning_Frequency 

Date_of_last_cleaning 

Descriptive_Comment 

Visible_WTC_dust_present 

Friable_asbestos_present 

Friable_asbestos_location 

Friable_asbestos_type 

Friable_asbestos_sq_ft 

Friable_MMVF_present 

Friable_MMVF_location 

Friable_MMVF_type 

Friable_MMVF_sq_ft 

Chalking_peeling_paint 

Chalking_peeling_paint_loc 

Chalking_peeling_paint_type 

Chalking_peeling_paint_sq_ft 

Part_or_comb_sources_unit 

Part_or_comb_unit_desc 

Part_or_comb_sources_bldg 

Part_or_comb_bldg_desc 

Source_Attribution_Comment 
38

Central_HVAC_system_present 

No_Central_HVAC_units_building 

No_Central_HVAC_ducts_unit 

Purpose_of_HVAC 

Central_HVAC_clean_replace 

Date_HVAC_cleaning 

Date_HVAC_replacement 

Central_HVAC_Comment