DRAFT N CEA - W - 1395 DO NOT CITE OR QUOTE E PA/600/P-2/002A October 2002 External Review Draft http://www.epa.gov/ncea



# Exposure and Human Health Evaluation of Airborne Pollution from the World Trade Center Disaster

National Center for Environm ental Assessm ent Office of Research and Development U.S. Environm ental Protection Agency October, 2002DISCLAIMER

This docum ent is a draft. It has not been form ally released by the U.S. Environm ental

Protection Agency and should not at this stage be construed to represent Agency policy.

Mention of trade nam e s or comm e rcial products does not constitute endorsem e nt or

recom m e ndation for use.

DRAFT--DO NOT QUOTE OR CITE i October 2002

### Table of Contents

Page

Executive Sum m a ry

I. Overall Purpose and Scope of Assessm ent

II. Exposure Assessm ent and Risk Characterization Approach

III. Monitoring Data

IV. Evaluation IV.a. Particulate Matter IV.b. Metals IV.c. Polychlorinated Biphenyls IV.d. Dioxins IV.e. Asbestos IV.f. Volatile Organic Compounds

V. Comm e nt on the First Several Days After Septem ber 11

VI. D ata on Occupational and Indoor Exposures V1.a. Occupational Exposures V1.b. Indoor Exposures

VII. Overall Comm e nts and Future Studies

VIII. References

Appendix A. W o rld Trade Center Health Effect s Screening Criteria for Am bient Air Developed by EPA’s Region 2

Appendix B. Table of Monitoring Locations

DRAFT--DO NOT QUOTE OR CITE ii October 2002List of Tables

Table 1. Inhalation health risk screening benchm arks used in this assessm ent.

Table 2. Concentrations (m axim um and Sept-Oct average) of PM 2.5 and Com ponent Elem ents Measured at the EPA/ORD W o rld Trade Center Perim e ter Sites and at Four Other Sites in the Northeast U.S. (PM 2.5 concentrations in μg/m 3 ; all other com ponents in ng/m 3 ).

Table 3. Summ a ry of PCB m onitoring data between Septem ber, 2001, and April, 2002.

Table 4. Measured dioxin TEQ air concentrations at the W T C Building 5 m onitor, the Church & Dey m onitor, and the Park Row m onitor (all units = pg TEQ/m 3 ; NR = not reported; all TEQ calculated at ND = 1⁄2 DL except values in parenthesis, which are calculated at ND = 0).

Table 5. Hum a n exposure and health risk assessm ent assum p tions and results for dioxin TEQs.

Table 6. Locations and concentrations of asbestos exceeding the AHERA level of 70 S/m m 2

.

Table 7. VOC sam p ling locations outside of Ground Zero.

Table 8. Locations that showed exceedences of screening benchm arks for VOCs and restrictions to access.

Table 9. Acetone grab sam p le exceedences and 24-hour sam p le m onitoring summ a ry.

Table 10. Benzene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

Table 11. 1,3-Butadiene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

Table 12. Chlorom e thane grab sam p le exceedences m onitoring summ a ry

Table 13. Ethylbenzene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

Table 14. Toluene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

DRAFT--DO NOT QUOTE OR CITE iii October 2002List of Figures

Figure 1. Figure showing the shrinkages of the restricted zones in the vicinity of Ground Zero over tim e. For exam ple, the area below Canal Street was no longer prohibited after 9/14, and sim ilarly, the shaded area beneath Cham bers Street becam e available only after 9/27. [Figure extracted from m ap supplied by City of New York, Em ergency Mapping Center].

Figure 2. Particulate m a tter m onitoring sites, including ORD surface sites (A, C, K) on the W T C perim e ter, the ORD site at 290 Broadway, and NYSDEC sites located elsewhere.

Figure 3. Spread of dense dust/sm oke cloud over all of lower Manhattan and drifting to the E/SE imm e diately after the Septem ber 11, 2001, collapse of the W o rld Trade Center buildings.

Figure 4. W o rld Trade Center plum e from intense fires (>1000 °F) during days following Septem ber 11, 2001, with high concentrations of both newly form ed fine particles from

com bustion and reentrained coarse particles likely being transported upward by convection processes and being dispersed in the W T C plum e over varying NY City areas, depending on prevailing wind directions and speeds.

Figure 5. ORD-m odeled W T C plum e dispersion on Septem ber 11, 2001, at 12 noon. The values indicated by red num erals are hourly PM 2.5 concentrations (in μg/m 3 ) m easured at preexisting NJ and NY State-operated PM m onitori ng stations in northern New Jersey and New York City. Red, orange, and yellow shading repr esent m o st likely areas of plum e dispersion (red = estim ated dilution to 100 thto 500 thand dark blue = dilution to <one m illionth of pollutant concentration at W T C source).

Figure 6. Satellite photograph of the W T C plum e lofting from Ground Zero at 11:43 am EDT on Septem ber 12, 2001. Note the very concentrated vertical convection of dust/sm oke particles upwards and the flow in a well-defined plum e towards the S/SE. (Source: Mandatory Credit:

“ spacei m a ging.co m ”).

Figure 7. Increased hourly PM 2.5 concentrations m easured on Septem ber 12 and/or 13 at PS 64, PS 199, Maspeth Library, and PS 274 to the E/SE of W T C, reflecting dispersal of newly form ed f i ne particles f r om W T C f i res and/or f i ne particles reentrained f r om the settled dust f r om initial collapse of the W T C buildings. (PM 2.5 data provided courtesy of NYSDEC).

Figure 8. ORD-m odeled W T C plum e dispersion for Septem ber 13, 2001 at 9:00 am

. Note the increased hourly PM 2.5 concentrations depicted in red for PS 64 (166 μg/m 3 ) and PS 199 (100 μg/m 3 ) NYSDEC m onitoring stations, consistent withthe E/NE direction of the m odeled plum e dispersion and likely touchdown of the plum e at those and intervening sites but not at sites further E, SE, or to the N.

Figure 9. ORD-m odeled W T C plum e dispersion on Septem ber 14, 2001 at 12 noon, indicative of plum e flow m a inly out over New York Harbor.

DRAFT--DO NOT QUOTE OR CITE iv October 2002Figure 10. Satellite photograph of W T C plum e lofting from Ground Zero at 11:54 am EDT on Septem ber 15, 2001, and dispersion to the S/SW out over the New York Harbor. (Source: Mandatory Credit: “spaceim a ging.com ”).

Figure 11. Panel A (top) : Daily PM 2.5 concentrations m onitored by EPA/ORD at sites A, C, and K around Ground Zero perim e ter and at 290 Broa dway 6 blocks northeast of Ground Zero. Panel B (bottom) : PM 2.5 concentrations observed at several extended m onitoring network sites in lower Manhattan within 3 to 10 blocks of W T C Ground Zero.

Figure 12. ORD-m odeled W T C plum e dispersion on October 4, 2001 at 3:00-4:00 a.m

. Note the general regional elevation of hourly PM 2.5 levels (in μg/m 3 ) indicated by red num erals for

m onitoring sites scattered across both northern New Jersey and NYC areas, even outside

m odeled areas of likely greatest plum e intensity indicated by red shading.

Figure 13. Daily PM 2.5 concentrations recorded at NYSDEC PS 64 m onitoring site after Septem ber 11, 2001 (9/11/01 to 10/27/01) com p ar ed to historic record of 24-hr PM 2.5 values at the sam e site during prior 2 years (2/23/00 to 9/01/01). Note exceedence of 40 μg/m 3 AQI Level of Concern on Septem ber 13 and likely again on October 4; red portion of bar indicates 24-hr average if three high hourly values (> 100 μg/m 3 ) being evaluated f o r data quality are included in 24-hr average calculation.

Figure 14. ORD m easurem ent of PM 2.5 elem ental constituents Ca, Si, and K at Ground Zero perim e ter sites and 290 Broadway site.

Figure 15. ORD m easurem ents of PM 2..5 elem ental com position for S, Cl, and Br at Ground Zero perim e ter sites and 290 Broadway site.

Figure 16. ORD m easurem ents of PM 2.5 elem ental constituents Pb, Cu, and Zn at Ground Zero perim e ter sites and 290 Broadway site.

Figure 17. ORD m easurem ents of PM 2.5 elem ental constituents As, Pd, and Sb at Ground Zero perim e ter sites and 290 Broadway site.

Figure 18. ORD m easurem ents of PM 2.5 elem ental constituents Ni, Cd, and Cr at Ground Zero perim e ter sites and 290 Broadway site.

Figure 19. PM 2.5 concentrations recorded on roof top of DOE Facility at Varick St., approxim a tely 2.0 m iles N/NE of Ground Zero. Note single very high PM 2.5 excursion m a inly restricted to m o rning hours of October 3 (see in set figure for October 3), consistent with ORD

m easurem ents at location A on the W T C north perim e ter and Ground Zero plum e plot shown in Figure 2 for October 3.

Figure 20. Am bient air lead concentrations (μg/m 3 ) at sites within Ground Zero or in lower Manhattan locations in imm e diate vicinity of the W T C.

Figure 21. Location of PCB m onitoring stations.

DRAFT--DO NOT QUOTE OR CITE v October 2002Figure 22. Location of dioxin air m onitoring. The locations m a rked “N” are New York State Departm e nt of Environm ental Conservation ( NYSDEC) sam p lers m a intained by EPA Region 2 with analysis of the sam p les by Region 7 (Region 2/7), whereas all other sam p lers are

m a intained by EPA’s Environm ental Response Team (EPA ERT). See text for discussion of the differences in the two sets of data from these two air m onitoring team s.
Figure 23. Location of asbestos m onitoring stations in Lower Manhattan.

Figure 24. Location of asbestos m onitoring stations in Staten Island and nearby locations in New Jersey (note: sam p ling sites in the Staten Island Landf ill identif ied only by num ber).

Figure 25. North-South directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 26. East-W est directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a)

Figure 27. Northwest-Southeast directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 28. Northeast-Southwest directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 29. North-South directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 30. East-W est directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 31. Northwest-Southeast directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 32. Northeast-Southwest directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 33. Location of VOC m onitoring stations outside Ground Zero.

DRAFT--DO NOT QUOTE OR CITE vi October 2002List of Acronyms and Abbreviations

ACGIH A m e rican Conference of Gove rnm e ntal Industrial Hygienists ACM asbestos-containing m a terials ADD Average Daily Dose AHERA Asbestos Hazard Em ergency Response Act AIRS Aerom e tric Inf o rm ation Retrieval System AQI Air Quality Index As arsenic ATSDR A gency for Toxic Substances and Disease Registry Br brom ine Ca calcium cubic centim eters Cd cadm i um CDC C enters for Disease Control and Prevention Cl chlorine CO carbon m onoxide Cr chrom i um Cu copper DL detection lim it DOE Departm e nt of Energy EOHSI E nvironm ental and Occupational Health and Saf e ty Institute EPA E nvironm ental Protection Agency EPA ERT E nvironm ental Protection Agency Environm ental Response Team EPA-STSC Environm ental Protection Agency Superfund Toxics Support Center ESD E nvironm ental Services Division, of EPA’s Region 7 Office in Kansas City f f ibers of asbestos FDNY Fire Departm e nt of New York FEMA Federal Em ergency Managem e nt Agency GFF glass f i ber f ilter HEAS Hum a n Exposure and Atm o spheric Sciences Division, in EPA’s NERL IBB increm ent in body burden K potassium kg kilogram LADD lifeti m e average daily dose LOC l evel of concern LW lipid weight MCL M axim um Contam inant Level μg m i crogram μm m i crom eter MOE M argin of Exposure MRL M inim um Risk Level NAAQS National Am bient Air Quality Standard NCEA National Center for Environm ental Assessm ent, of EPA’s Office of Research and Developm ent

DRAFT--DO NOT QUOTE OR CITE vii October 2002 ccND Non-detect NERL National Exposure Research Lab of EPA’s Office of Research and Developm ent ng nanogram NHEERL N ational Health and Environm ental Exposure and Risk Laboratory, of EPA’s Office of Research and Developm ent NIEHS N ational Institute of Environm ental Health and Saf e ty NIOSH N ational Institute f o r Occupational Saf e ty and Health NO 2 nitrogen dioxide NOAEL no-observed-adverse-effect level NY New York NYC New York City NYCDEP N ew York City Departm e nt of Environm ental Protection NYCDOHMH N ew York City Departm e nt of Health and Mental Hygiene NYSDOH New York State Departm e nt of Health NYSDEC N ew York State Departm e nt of Environm ental Conservation ORD E PA’s Office of Research and Developm ent OSHA Occupational Safety and Health Adm i nistration PAH polycyclic arom atic hydrocarbons Pb lead PCB polychlorinated biphenyl com pounds PCM phase contrast light m i croscopy Pd palladium PEL P erm i ssible Exposure Lim i t pg picogram PM, PM 2.5 , PM 10 Particulate m a tter, and PM at less than 2.5 μm and less than 10 μm diam eter ppb part per billion ppm part per m illion PS public school PUF polyurethane foam plug for air m onitoring REL R ecomm e nded Exposure Levels RfC R eference Concentration S s ulfur, or structures of asbestos Sb antim ony SF cancer slope factor Si silica SO 2 sulfur dioxide SRIXE s ynchrotron radiation-induced X-ray em ission STEL Short Term Exposure Level STSC Superfund Technical Support Center TEF toxicity equivalency factor TEM transm ission electronic m i croscopy TEOM t apered elem ent oscillating m i crobalance TEQ toxic equivalent concentration TLV Threshold Lim it Value

DRAFT--DO NOT QUOTE OR CITE viii October 2002TW A tim e-weighted average UR unit risk, for estim ating cancer risk due to inhalation USGS United States Geological Survey VAPS v ersatile air pollutant sam p ler VOC Volatile organic com pound W T C W orld Trade Center XRF x -ray flourescent Zn zinc

DRAFT--DO NOT QUOTE OR CITE ix October 2002FOREWORD

The National Center for Environm ental Assessm ent (NCEA), a m a jor com ponent of the Office of Research and Developm ent (ORD), is EPA' s national resource center for hum an health and ecological risk assessm ent. NCEA conducts risk assessm ents, carries out research to im prove the state-of-the-science of risk assessm ent, and provides guidance and support to risk

assessors.
Following the collapse of the W o rld Trade Center towers on Septem ber 11, 2001, New York State and Federal agencies initiated num erous air m onitoring activities to better understand the ongoing im pact of em issions from the disaster. This report focuses on these air m easurem ent data, evaluating them in term s of what is typical for New York City or general urban background and interpreting it with regard to the potential for hum an health consequences. The report does not evaluate exposures possibly faced by rescue or clean-up workers and briefly discusses past and current indoor m onitoring efforts.

The analysis in this report supports three general findings: 1) Persons exposed to the extrem ely high levels of am bient particulate m a tter and its com ponents during the collapse of the W o rld Trade Center towers and for several hours afterwards were likely to be at risk for im m e diate acute (and possibly chronic) respir atory and other types (e.g., cardiovascular) of sym p tom s

. 2) The first m easurem ents of som e of the contam inants were on Septem ber 14, while other contam inants were not m easured until Septem ber 23. Available data suggest that the concentrations within and near Ground Zero were likely to be highest in the few days following Septem ber 11. Because there are only lim ited data on these critical few days, exposures and potential health im pacts cannot be evaluated with certainty for this tim e period. 3) Except for exposures on Septem ber 11 and possibly during th e next few days, persons in the surrounding

com m unity were unlikely to suffer short-term or long-term adverse health effects caused by exposure to elevations in am bient air concentrations of the contam inants evaluated in this report. These elevated concentrations were m easured m o stly within and near Ground Zero, and they lasted for one to three m onths after Septem ber 11. The m onitoring data indicate that air concentrations decreased to background levels that are characteristic of pre-Septem ber 11 levels in the New York City m e tropolitan area by around January or February of 2002.

Ultim ately, it will be dif f i cult to ascertain with certainty what ef f ects resulted when people were surrounded by initial clouds of dust, or were subsequently exposed to the elevated concentrations that are discussed in this report. Epidem iologic studies of the exposed populations that are being conducted by various agencies and institutions should provide a m o re scientifically robust evaluation for future evaluations of health effects.

George W

. Alapas Acting Director National Center for Environm ental Assessm ent

DRAFT--DO NOT QUOTE OR CITE x October 2002AUTHORS, CONTRIBUTORS, AND REVIEWERS

The National Center for Environm ental Assessm ent (NCEA), Office of Research and Developm ent, was responsible for preparing this docum ent. Matthew Lorber and Herm an Gibb, of NCEA, provided overall direction and coordination of the production effort.

AUTHORS

Executive Summ a ry

Section I. Overall Purpose and Scope of Assessm ent

Section II. Exposure Assessm ent and Risk Characterization Approach

Section III. Environm ental Monitoring

Section IV. Evaluation

IV.a. Particulate Matter

IV.b.1. Lead

IV.b.2. Chrom i um and Nickel

IV.c. P olychlorinated Biphenyls

IV.d. Dioxins

IV.e. A sbestos

IV.f. V olatile Organic Com pounds Herm an Gibb Matthew Lorber Linda Tuxen

H erm a n Gibb Matthew Lorber John Schaum

Matthew Lorber Herm an Gibb Nancy B. Beck

Herm an Gibb Matthew Lorber

L ester Grant Joseph Pinto

Lester Grant Joseph Pinto

Nancy B. Beck

D avid Cleverly

Matthew Lorber

M atthew Lorber Aparna Koppikar Paul Wh ite

Nancy B. Beck Matthew Lorber

V. Comm e nt on the First Several Days After Septem ber 11 Matthew Lorber

DRAFT--DO NOT QUOTE OR CITE xi October 2002VI. D ata on Indoor and Occupational Exposures Matthew Lorber John Schaum

VII. Comm e nts and Future Studies Herm an Gibb Matthew Lorber Nancy B. Beck

VIII. References

CONTRIBUTORS

The following individuals have also provided valuable support in the review and com m e nt of this docum ent, as well as supplying text and other m a terials for individual sections:

Stephen H. Gavett, NHEERL/ORD/US EPA Sven Rodenbeck, ATSDR Audrey Galizia, Region 2, US EPA Barbara Finazzo, Region 2, US EPA Mark Maddaloni, Region 2, US EPA Marcus Kantz, Region 2, US EPA Robert Kelly, Region 2, US EPA

REVIEWERS

Philip J. Landrigan, M.D., M.Sc. Ethel H. W i se Professor Comm unity Medicine Chairm an, Departm e nt of Comm unity and Preventive Medicine Mount Sinai School of Medicine One Gustave L. Levy Place Box 1057 New York, New York 10029-6574

Paul J. Lioy, Ph.D Associate Director Environm ental and Occupational Health Sciences Institute of New Jersey UMDNJ-Robert W ood Johnson Medical School, and Rutgers University 170 Frelinghuysen Road Piscataway, NJ 08854

George D. Thurston, Ph.D Associate Professor NYU School of Medicine National Institute of Environm ental Medicine 57 Old Forge Rd. Tuxedo, NY 10987

DRAFT--DO NOT QUOTE OR CITE xii October 2002

## Executive Summary

In the days following the Septem ber 11, 2001, terrorist attack on New York City’s W o rld Trade Center (W TC) towers, m a ny federal agencies, including the United States Environm ental Protection Agency (EPA), were called upon to bring their technical and scientific expertise to the national em ergency. EPA, other federal agenci es, and New York City and New York State public health and environm ental authorities initiated num erous air m onitoring activities to better understand the ongoing im pact of em issions from that disaster. These efforts generated an im m e nse am ount of data. Many EPA offices and program s quickly becam e involved with these activities, providing scientific, engineering, public health, and m a nagem e nt expertise to help cope with the after effects of the collapse of the W T C towers. EPA Region 2, which includes the New York City m e tropolitan area in New York and New Jersey, is the Agency’s lead of f i ce on these activities, including the im portant and com p licated task of com m unity outreach and

com m unication. As part of these activities, Re gion 2 requested that EPA’s Office of Research and Developm ent (ORD) conduct a hum an health evaluation of exposure to air pollutants resulting from the W T C disaster.

The evaluation in this report relies prim arily on the analyses of am bient air sam p les from

m onitors located at the perim e ter of the W T C Ground Zero and at various other sites in lower Manhattan and surrounding areas. It is an assessm ent of the inhalation exposure and potential hum an health risk incurred by the general population residing and working in the vicinity of the W T C. Num e rous other efforts have been conduc ted or are ongoing that address other aspects of exposure and potential risk associated with the collapse of the W T C towers, including:

1) Ground Zero worker exposures : This report reviews som e of the data collected by the Occupational Saf e ty and Health Adm i nistration (OSHA) and the National Institute of Occupational Safety and Health (NIOSH) that a ddress the exposures faced by firem a n and rescue workers, but does not explicitly evaluate these exposures.

2) Indoor exposures: Sim ilarly, this report reviews som e of the data collected on indoor air and dust, particularly a recently com p leted study by the New York City of Departm e nt of Health and Mental Hygiene (NYCDOHMH) and th e Agency for Toxic Substances and Disease Control (ATSDR). It also provides an overvie w of the ongoing efforts by EPA Region 2 to clean apartm ents and evaluate the quality of indoor air and dust. Future reports by EPA Region 2 will detail these ef f o rts and m onitoring results.

3) Epidem iology studies: Chapter 7 of this report provides an overview of the types of studies that are ongoing which will evaluate health im pacts experienced by workers and others known to be in the vicinity of W T C in the days and weeks following Septem ber 11, 2001. These studies are being conducted and sponsored by the National Institute of Environm ental Health Studies (NIEHS), and others.

The am bient air m onitoring activities described in this report were undertaken by federal, state and local agencies which have m a de their analytical results available to EPA for analysis. Most of the m onitors were placed following the disaster, with the intent of characterizing outdoor levels of W T C-generated air pollutants at locations surrounding the W T C site at

DRAFT--DO NOT QUOTE OR CITE 1 October 2002different distances. Som e m onitors for particulate m a tter (PM), operated by New York State, existed prior to the disaster.

This report focuses on: PM, metals (lead, chromium and nickel compounds)

, polychlorinated biphenyls (PCBs) , dioxin-like compounds, asbestos, and volatile organic compounds (VOCs)

. These substances are included because m onitoring indicated that they correlated with the disaster site in both tim e and space, and because they pose a potential concern for health im pacts. PM was generated by the collapse of the W T C buildings, the recovery and dem o lition operations, and the lingering f i re. Lead and asbestos were believed to be com ponents of the W T C building m a terials. PCBs were used as dielectric fluid in transform e rs and capacitors. Dioxin and VOCs are produced as a result of com bustion and volatilization f r om f

u els. The assessm ent is lim ited to an evaluation m a inly of the inhalation of airborne contam inants, although dust ingestion and derm al contact m a y also have led to exposures within and near Ground Zero.

Elevated concentrations of these contam inants were found within and near Ground Zero for a short period of tim e after Septem ber 11. “Elevated” is used in this discussion to denote concentrations of a contam inant that were significantly higher, by a factor of 10 or m o re and often by factors of 100 or 1000, com p ared to other m easurem ents of the contam inant taken in the W T C m onitoring program or com p ared to concentrations that are typically found in New York City or in general United States urban settings. Many of these elevated m easurem ents were identified as having occurred in “restricted zones,” that is, zones where access was lim ited to

em ergency m a nagem e nt and rescue personnel and to other credentialed people. In general, the

m onitoring data, even within Ground Zero, indicate that am bient air levels for all of these substances decreased to background ambient concentrations that are characteristic of preSeptem ber 11 levels in the New York City m e tropolitan area by around January or February of 2002.

The analysis in this report finds that:

! Persons exposed to the extremely high levels of ambient particulate matter and its components during the collapse of the World Trade Center towers and for several hours afterwards were at risk for immediate acute (and possibly chronic) respiratory and other types (e.g., cardiovascular) of symptoms.

! The first measurements of some of the contaminants were on September 14, while other contaminants were not measured until September 23. Available data suggests that the concentrations within and near Ground Zero were likely to be highest in the few days following September 11. Because there are only limited data on these critical few days, exposures and potential health impacts cannot be evaluated with certainty for this time period.

! Except for exposures on September 11 and possibly during the next few days, persons in the surrounding community were unlikely to suffer short-term or long-term adverse health effects caused by exposure to elevations in ambient air concentrations of the contaminants evaluated in this re port. These elevated concentrations were

DRAFT--DO NOT QUOTE OR CITE 2 October 2002measured mostly within and very near Ground Zero, and they lasted for 1 to 3 months after September 11.

Wh ile the conclusions reached in this report represent the current scientific understanding of the toxicity that these contam inants pose to people, com b ined with EPA’s evaluation of exposure to these contam inants based on available air m onitoring data, it cannot be stated with certainty what effects resulted when people were engulfed in the initial cloud of dust or were subsequently exposed to the elevated concentrations that were found. Epidem iologic studies of the exposed populations that are currently being conducted by various agencies and institutions should provide a m o re scientifically robust evaluation for future evaluations of health effects.

The risk evaluation approach taken in m o st instances was to com p are the m easured air levels at locations near Ground Zero to established health benchm arks for inhalation exposure and to typical urban background levels. OSHA Perm issible Exposure Levels (PELs), NIOSH Recom m e nded Exposure Levels (RELs), and Agency for Toxic Substances and Disease Registry (ATSDR) Minim u m Risk Levels (MRLs) were am ong the benchm arks included in this evaluation. W h ere available, benchm arks established to protect against acute and subchronic exposures were used. Benchm arks that are intended to protect against exposures lasting over one year or throughout a lifetim e, like the EPA Reference Concentration (RfC), were only used if other m o re appropriate benchm ark values were not available.

A sim p le com p arison of air m easurem ents to health benchm arks or to typical background levels can be thought of as a “screening” exercise; the purpose of the exercise is to identify possible problem s. If the m a jority of sam p les are m u ch less than a benchm ark, in m o st cases it would be appropriate to conclude that a health im pact is unlikely. Sim ilarly, if m o st air

m easurem ents are sim ilar to typical background levels, then it can be concluded that em issions from the W T C are not im pacting air or influenc ing exposure and health. On the other hand, if

m o st sam p les exceed a benchm ark, then it m a y be appropriate to consider the possibility that a health im pact m a y have occurred, or could occur, depending on the circum stances.
Efforts will continue at EPA to further characterize exposures and health im pacts that resulted from the collapse of the W T C Towers, and to build on the risk evaluation presented in this report. Som e additional future considerations could include: evaluating other contam inants that were m easured, evaluating the indoor envir onm ent in m o re depth, evaluating other pathways of exposure and other exposure m e dia such as derm al contact to contam inated dust, investigating the com b ined effects of exposure to m o re than one contam inant, conducting further toxicity testing with laboratory anim als, and consider ing results from ongoing epidem iological studies.

Summ a ries of the findings for each contam inant/class of contam inants are presented below:

Particulate Matter. People caught in the initial dust/smoke cloud that encompassed lower Manhattan after the collapse of the WTC buildings on September 11 were briefly exposed (4 - 8 hours) to quite high levels (in the milligrams per cubic meter, mg/m 3 , range) of airborne particulate matter (PM)

. Also, during the first several days after the disaster, PM levels in the air at the WTC perimeter exceeded EPA’s daily PM 2.5 NAAQS (65 μg/m 3 , 24-hr) ; and PM 2.5

DRAFT--DO NOT QUOTE OR CITE 3 October 20024 DRAFT--DO NOT QUOTE OR CITE October 2002 concentrations at some other nearby lower Manhattan sites exceeded EPA’s 40 micrograms per cubic meter (μg/m 3 ) 24-hour Air Quality Index (AQI) level of concern for susceptible subgroups. The high PM concentrations recorded very near WTC Ground Zero during late September and early October may imply increased chronic health risks for the most highly exposed individuals (e.g., persons spending extended periods of time within the WTC work zone without wearing protective respirators). By mid- to late October, PM values across lower Manhattan had largely returned to levels typical of New York City and other US urban areas, with only a few WTC or nearby sites occasionally approaching or exceeding the AQI level of concern.

Many individuals were exposed for a few hours to very high PM concentrations in the initial dust cloud that spread over lower Manhattan on September 11. Also, high levels of airborne particles were detected during the first several days after September 11 at a few already existing PM monitoring sites scattered across the New York City area. Hourly or daily fine particle (less than 2.5 μm in diameter, PM 2.5 ) values at some new sites set up by EPA or New York State exceeded 40 μg/m 3 (though the AQI applies only to the daily averages).

PM 2.5 measurements from newly established monitoring sites around the WTC perimeter varied widely, depending on wind dir ection. Daily average (24-hr) PM 2.5 concentrations on some days exceeded 200 μg/m 3 at one WTC perimeter site or another during late September and early October. However, PM 2.5 concentrations decreased rapidly with distance from the WTC, with few PM 2.5 values exceeding the 40 μg/m 3 AQI at monitoring locations ranging from 3 to 10 blocks away from the WTC. During the entire period following September 11, PM 2.5 values recorded at lower Manhattan sites away from the WTC perimeter were not markedly di fferent than during periods before or since, as the New York metropolitan area routinely experiences PM 2.5 values near and above the AQI.

Concentrations of various elements (e.g., calcium, sulfur, silicon, lead, and other metals) in WTC PM 2.5 particles also were enriched above typical background levels on an episodic basis at sites mainly on or near the WTC perimeter, including on some days extending into late October and into November.

The issue of alkalinity of WTC dust and its potential as a possible health concern for exposed individuals is raised by observations by the United States Geological Survey (USGS) and academic researchers of high pH (> 11.0) of aqueous solutions of settled WTC dust not leached by rainfall. After late September, indoor exposures to such dust probably warrant more concern than outdoor exposures for possible acute irritative effects or more chronic health effects, not only because of the basic nature of some constituent particles but also because of other unusual features, such as slender microscopic glass fibers with toxic materials attached to them or very fine particles composed of unusual combinations of silica coalesced with lead or other toxic materials.5 DRAFT--DO NOT QUOTE OR CITE October 2002 Metals

Lead. Persons caught in the initial WTC-related dust cloud experienced brief exposures to high levels of lead (Pb ) , based on analyses of deposited dust samples. In late September 2001, air lead concentrations at the WTC perimeter sites reached levels above 1.5 μg/m 3 on some days. However, the air lead levels averaged over 90 days (late September - late November) did not exceed the EPA National Ambient Air Quality Standard (NAAQS) of 1.5 μg/m 3 averaged over a 90-day period. After mid-October, air lead at all sites in lower Manhattan outside WTC Ground Zero dropped to levels more comparable with background concentrations typical of NYC and other northeastern United States urban areas. On the basis of ambient air and dust data, there is little indication of any substantial health risks being associated with lead exposures of the general population in lower Manhattan areas around the WTC site.

On several days in late September 2001, 24-hour Pb concentrations at the WTC Ground Zero perimeter sites exceeded 1.5 μg/m 3 . This level was again approached or exceeded at one or another WTC perimeter site dur ing early October (10/3 -10/5). However, airborne Pb rapidly decreased with distance from the WTC perimeter sites, with Pb concentrations on the same days when Pb levels were elevated at Ground Zero being substantially lower at several locations within 3-10 blocks from the WTC (i.e., mostly within the 0.11 to 0.63 μg/m 3 range of 24-hour Pb levels observed at some Manhattan and Brooklyn sites during the 1990's). After mid-October, 2001 Pb readings for all WTC perimeter sites and other lower Manhattan sites remained below 1.5 μg/m 3 , with few even exceeding 0.5 μg/m 3

. Lead concentrations in bulk dust samples taken close to the WTC within days after September 11 ranged up to 625 μg/g (ppm). This level is well below street dust Pb levels on or near heavily traveled roadways prior to phase-down of Pb in gasoline in the late 1970's, which often were well in excess of 1000 - 2000 ppm, and it compares well with the 500 - 1000 ppm street dust or soil lead levels found in northeastern or midwestern U.S. urban areas well into the 1990s.

In general, the observed ambient air lead levels did not appear to pose increased health risks for the general public. However, susceptible persons (especially any pregnant women) who may have experienced extended exposures to elevated Pb levels within WTC Ground Zero work areas while not wearing appropriate respiratory protective gear or who were exposed to indoor WTC-derived dusts with high Pb loadings could possibly be at increased risk for chronic health effects. Evaluation of blood lead levels and pertinent medical records for any pregnant women exposed at Ground Zero or in its immediate vicinity during late September/earlyOctober could provide useful further data by which to assess any such possible health risks associated with WTC-generated lead emissions.

Chromium. Samples evaluated for total chromium at Ground Zero and at sites surrounding Ground Zero never exceeded the OSHA PEL of 1 mg/m 3 or the ATSDR Intermediate Minimum Risk Level (MRL) for chromium VI particulates of 1.0 μg/m 3

. On the basis of the samples evaluated, exposures to chromium were not likely to cause any adverse health effects.6 DRAFT--DO NOT QUOTE OR CITE October 2002 All 21 Ground Zero air samples evaluated for total chromium were collected at Building 5 between September 23 and January 31. Additionally, approximately 512 air samples collected at sites surrounding Ground Zero were evaluated for chromium, including 86 samples collected at landfills and 16 samples from personal air monitors worn by New York City fire department personnel. No exceedences of the OSHA PEL or the ATSDR Intermediate MRL for chromiumVI particulates were detected. However, it was noted that concentrations in the range of 0.20 and 0.40 μg/m 3 were measured for about a month month after September 11, to then drop to more typical urban backgrounds less than 0.10 μg/m 3

Nickel. Nickel samples evaluated at Ground Zero and at sites surrounding Ground Zero never exceeded the OSHA PEL of 1 mg/m 3

. On the basis of samples evaluated, exposures to nickel were not likely to cause any adverse health effects.

All 21 Ground Zero air samples evaluated for nickel were collected at Building 5 between September 23 and January 31. Additionally, approximately 637 air samples collected at sites surrounding Ground Zero were evaluated for nickel, including 86 samples collected at landfills. No exceedences of the OSHA PEL were detected. Furthermore, and unlike chromium and other contaminants, all measurements from September 11 on at all sites were at background levels.

Polychlorinated Biphenyls. Of the several hundred polychlorinated biphenyl (PCB) air measurements available, only one sample was elevated above 100 nanograms total PCB per cubic meter (ng/m 3 ), at 153 ng total PCB/m 3 , and only three samples were above 50 ng total PCB/m 3 . This compares to typical urban background PCB concentrations in the range of 1 - 8 ng total PCB/m 3 . After a month, nearly all readings were in the range of typical urban PCB concentrations or were not detected. There were no exceedences of any short-term occupational health benchmark, including the NIOSH REL of 1*10 3 ng/m 3 or the OSHA PEL of 5*10 3 ng/m 3

. It is concluded that exposures were of minimal concern for cancer risk.

Several hundred PCB air measurements were obtained at a total of 12 locations in the vicinity of Ground Zero from September 16, 2001, through April 24, 2002. The highest PCB air concentration measured was 153 ng PCB/m 3 , and this occurred on October 2, 2001, at the Ground Zero site, WTC Building 5 SW. Typical urban air concentrations of PCBs are in the range of 1 - 8 ng/m 3 . The source of these elevated PCB air measurements is speculated to be the smoke emanating from the smoldering fires at Ground Zero. PCBs were entrained in the smoke as a consequence of PCB-containing materials in the WTC buildings. After November 3, 2001, all of the PCB monitoring sites showed results consistent with PCB levels in air that are typical of urban areas of the U.S. A simple screening exercise showed that an incremental lifetime cancer risk due to exposure to short-term elevation of PCBs would be in the range of 10 -8 or lower, which is judged to be of minimal concern. With respect to non-cancer effects, all PCB air measurements are several orders of magnitude below No Observed Effect Levels (NOELs) in experimental animal studies. In addition, levels of PCBs observed near or at the WTC site are below the NIOSH REL of 1*10 3 ng/m 3 (NIOSH, 2002), and several7 DRAFT--DO NOT QUOTE OR CITE October 2002 orders of magnitude below the OSHA PEL of 5*10 5 ng/m 3 . The NIOSH REL is an 8-hr time-weighted average air concentration. It is associated with long-term or repeated exposures, and is protective of effects on the liver and the reproductive system. The OSHA PEL is also an 8-hr time-weighted averag e air concentration. It is associated with long-term or repeated exposures and is protective of effects on the ski (dermatitis).

Dioxins. Monitoring data indicate that dioxin toxic equivalent (TEQ) levels in air near the WTC were up to three orders of magnitude higher (1000 times higher) than is typical for urban areas in the United States. Typical levels for urban areas are 0.1 to 0.2 picograms of TEQ per cubic meter (pg TEQ/m 3 ), while levels found in Ground Zero and near Ground Zero, starting September 23 (the date of the first sample taken) and continuing through late November ranged from 10 to over 150 pg TEQ/m 3 . Concentrations measured several blocks from Ground Zero were still elevated above typical urban background, but considerably lower than sites in or near ground zero, ranging from 1 to 10 pg TEQ/m 3 during this same time period. Everywhere these elevations dropped rapidly, and the data suggest that by December 2001, levels decreased to background levels. These levels need to be considered in the context of total exposure to dioxin, 95% of which is attributed to dietary intake in normal background settings. Therefore, although inhalation exposure to dioxin at these elevated air concentrations is significantly higher than typical inhalation exposure to dioxin, an individual’s overall exposure to dioxin may not be impacted significantly. An exposure and risk screening exercise was conducted with available monitoring data, and the results suggest that these elevations did not result in a significant elevation in cancer or non-cancer risk over the background risk for exposure to dioxin-like compounds.

The monitoring data indicate that, through late November, dioxin TEQ levels in air near the WTC were distinctly elevated compared with typical levels in urban air. An exposure and risk screening exercise based on these high concentrations suggest a temporary elevation in exposures for Ground Zero workers but very minimal impact for nearby residents and office workers. It is conc luded that these potential exposures during 2001 do not constitute a public health concern. Dietary intake of dioxins is much higher than inhalation intake, and thus, the ambient concentrations of dioxin within and near Ground Zero, although considerably elevated above t ypical urban air concentrations of dioxin, are not as significant as suggested by the orders of magnitude in elevation indicated above.

However, much of the data obtained from within and near the WTC site are of limited interpretive value due to high detection limits. When dioxin-like compounds were not detected in an air sample, the TEQ concentration was determined by assuming that each dioxin-like compound was present in the air at one-half the detection limit for that compound. This is typical for calculating dioxin TEQ concentrations, and for other contaminants as well. Because dioxin-like compound concentrations were considerably elevated in the ambient air from September through late November 2001 within and near Ground Zero, these concentrations were able to be measured, despite high detection limits. Concentrations ranged from 10 to 150 pg TEQ/m 3 during this time, which was between 100 and over 1500 times higher than typically found in urban air.8 DRAFT--DO NOT QUOTE OR CITE October 2002 The reported TEQ concentrations that were compromised due to high detection limits ranged in value from 0.5 to 5.0 pg TEQ/m 3 , which is about 5 to 50 times higher than normal urban background air concentrations. These measurements came from 9 specific air samplers which were located within Ground Zero (1 sampler) and near the WTC site (8 samplers). In general, the dioxin method’s detection limit is calculated by dividing the lowest mass of dioxin that the method can detect by the air that contained that amount, namely the air that flowed through the sampler. Thus, as more air is drawn through the sampler, the detection limit is lowered. These 9 air samplers operated for 8-hour periods, and drew in about 7 m 3 of air. They began operation on September 23, 2001.

Three other air samplers were operated for 72-hour periods, and drew in about 1000 m 3 of air. These monitors were located several blocks from the perimeter of Ground Zero, and began operation on October 12. Because much more air was drawn into these samplers, the detection limits obtained for the dioxin-like compounds were lower, and TEQ concentrations could be routinely quantified as levels less than 1.0 pg TEQ/m 3 . The first sampling events in October through November in these three monitors resulted in concentrations that were still elevated above typical background TEQ concentrations, at between 1 and 10 pg TEQ/m 3 . Starting at the beginning of December, 2001, and continuing through the termination of sampling in May of 2002, the measurements in these samplers decreased to levels that were mostly less than 0.10 pg TEQ/m 3 . More detail on these two sets of monitors (the 9 monitors sampling for 8 hours, and the 3 monitors sampling for 72 hours) is provided in Section IV.d below.

All the reported TEQ measurements from these 9 monitors for 2002, and the measurements from them in upwind conditions during 2001 (i.e., when the plume was moving in a direction opposite the monitors), were in this one-half detection limit range of 0.5 to 5.0 pg TEQ/m 3 . Thus, the ability to assess exposure during the early months of 2002, where there may have been elevations near Ground Zero as a result of cleanup activities, was compromised. Because the health risk from dioxin exposure is associated with accumulation of residues in body tissues, continued dioxin TEQ exposure within and near Ground Zero throughout 2002 could not be evaluated. The risk screening exercises conducted for dioxin were limited to the time period when the concentrations were highest and dioxin was detected. This issue is described in more detail in Section IV.d.

Asbestos: The large majority of outside air measurements of asbestos were below established benchmarks and within the range of typical background levels. However, and similar to other contaminants, the few exceedences that were measured occurred near September 11 in time and close in proximity to the WTC. Limited available evidence suggest the incursion of asbestos to the indoor environment. A small study which sampled the indoor environment of two apartments on September 18 showed very high indoor levels of asbestos. A larger and more systematic study which sampled in November and December of 2001 suggested that indoor levels of asbestos in dust were slightly higher near the WTC as compared to indoor levels in dust further away. Current efforts by the EPA focus on the measurement and clean-up of residential apartments near the WTC.9 DRAFT--DO NOT QUOTE OR CITE October 2002 A total of 12,676 ambient samples in lower Manhattan were measured by phase contrast light microscopy (PCM, used to identify structures greater than 5 μm in length), and 8,872 of these were also measured by transmission electronic microscopy (TEM; used to identify structures less than 0.5 μm in length). Only 23 samples were found to exceed the Asbestos Hazard Emergency Response Act (AHERA, which uses the TEM measurement technique) abatement standard of 70 structures per square millimeter (S/mm 2 ), and there were no exceedences of the OSHA PEL (which uses the PCM measurement technique) of 0.1 fiber per cubic centimeter (f/cc). Most of the exceedences of the AHERA standard occurred during September 2001 adjacent to Ground Zero in “restricted zones”. The highest concentrations of PCM-measured fibers in ambient air were recorded during the 30 days following September 11, 2001, at sites in the vicinity of the WTC. Concentrations during this time were in the range of 0.04 to 0.08 f/cc. There has been a steady decline in the asbestos levels through the first few months of 2002, to correspond to a steady background state of ND to <20 S/mm 2 as measured by TEM and in the range of 0.003 f/cc as measured by PCM, a level which is typical for urban background.

A slightly higher occurrence rate of AHERA exceedences occurred within the exclusion zone at the Staten Island Landfill; 51 out of 5,207 samples taken. Most of the exceedences occurred during October and November 2001, corresponding to the time that most of the debris was being unloaded. Only one sample in Queens was above 70 S/mm 2 , whereas no exceedences were observed in the other boroughs of NYC or in New Jersey.

The highest measurements of asbestos available for evaluation in this report were taken within two apartments sampled on September 18, 2001. One apartment was highly affected by the collapse of the WTC towers with completely shattered windows and dust piled throughout the apartment. The other was in a building that had little exterior damage, but had visible dust on surfaces within the building and in the apartment sampled. In the severely damaged apartment, five air measurements of asbestos ranged from 6277 to 10,620 S/mm 2 using the AHERA protocol. One sample taken just outside on a window ledge of this apartment measured 548 S/mm 2 . However, it is likely this high reading was influenced by the air quality on the inside of the apartment, which showed exceedingly high asbestos concentrations, and was likely not representative of outdoor concentrations. The six indoor samples in the less impacted apartment exceeded the 70 S/mm 2 AHERA standard at levels ranging from 141 to 379 S/mm 2 . A rooftop sample at this location was low at 6.5 S/mm 2

. A systematic study of residential apartments by the NYCDOHMH and the ATSDR showed very little impact to residential apartments compared with this September 18 study, but still a difference between apartments in lower Manhattan and comparison apartments. From November 4 through December 11, 2001, environmental samples were collected in and around 30 residential buildings in lower Manhattan. In addition, four buildings above 59th Street were sampled and used as a comparison area for this investigation. Importantly, asbestos was not detected above background levels in air samples in all apartments sampled (with background defined as 0.003 f/cc, a level which is typical for urban background). Bulk dust samples were collected both indoors and on10 DRAFT--DO NOT QUOTE OR CITE October 2002 outdoor surfaces and analyzed for the presence of asbestos by both PLM (polarized light microscopy) and TEM. Asbestos was detected in settled indoor dust in 10 of 57 (16%) lower Manhattan residential units sampled, with the positive samples showing a maximum of 1.5% asbestos in dust. By comparison, no asbestos was detectable in dust samples collected in the 5 comparison residences. In outdoor dust collected at lower Manhattan properties, asbestos was detected in 6 of 14 (43%) samples, with a maximum asbestos concentration in dust of 3.4%.

Volatile Organic Compounds

. The Ground Zero samples of volatile organic compounds (VOCs) were generally not taken in the breathing zone of workers and were not representative of the general air quality at the site. Most of the data were collected within plumes from fires and smoldering rubble to alert the Fire Department of New York (FDNY) and the contractors/union health/safety officers working at Ground Zero about conditions that posed immediate health concern to the workers and, as such, were more representative of emissions rather than exposures. For this reason, an analysis of Ground Zero worker exposures for VOCs was not conducted. However, eleven VOCs were evaluated at sites surrounding Ground Zero. No exceedences of screening benchmarks were seen for 1,4-dioxane, ethanol, styrene, tetrahydrofuran, and xylenes. Exceedences of screening benchmarks were seen for acetone, benzene, 1,3-butadiene, chloromethane, ethylbenzene, and toluene. Except for benzene, exceedences for these chemicals occurred in restricted zones. Also, the exceedences were all grab samples. Twenty-four hour samples of benzene, 1,3-butadiene, ethylbenzene, and toluene all were about three orders of magnitude (1000 times) lower than the grab samples, demonstrating the difference between 4-minute grab samples taken within plumes and day-long averages. The exceedences for benzene were more frequent, some were further from Ground Zero than the other VOCs, and the 24-hour samples were lower but within a factor of 10 of the grab sample exceedences. This suggests that elevated concentrations of benzene (above typical background by about a factor of 10) may have been sustained for a month or more after September 11.

On the basis of available monitoring data, it is concluded that the exceedences of the screening benchmarks in restricted zones for acetone, 1,3-butadiene, chloromethane, ethylbenzene, and toluene do not represent a public health risk to persons living or working at sites surrounding Ground Zero.

The data for benzene were not as definitive. Because the 24-hour samples were measured at levels that were closer in magnitude to the grab sample exceedences than the other VOCs, within a factor of 10, this would suggest that the grab sample concentrations were closer to sustained concentrations rather than short-term plume concentrations only. Also, these 24-hour concentrations were near the ATSDR Intermediate MRL of 0.004 ppm and higher than the historical average for New York City of about 0.0005 ppm. The data suggest that the possible exposures to benzene at levels that approach the MRL did not last longer than 45 days. Whether or not specific health effects occurred due to exposure to benzene is unknown, but given that the exceedences and elevations above typical background were near Ground Zero and mostly within restricted zones, the data suggests that the exposures to the general population were of minimal concern.11 DRAFT--DO NOT QUOTE OR CITE October 2002 Air Concentrations During the First Several Days After September 11: An event such as September 11 demonstrates that the greatest environmental impacts occur in the first 24 to 48 hours and in areas close to the site. Difficulties associated with site access and security, power supply sources, equipment availability and analytical capacity hindered efforts by EPA and the New York State Department of Environmental Conservation (NYSDEC) to put air monitors in place immediately after the attack. While dust samples were collected for analysis on September 11, the first air samples of some of the critical contaminants were not taken until September 14, such as asbestos, while other contaminants were not sampled until September 23, such as dioxin. Rapid initiation of monitoring will allow the measurement of air concentrations that can be very important for evaluation of inhalation exposures and potential short and long-term human health impacts. An examination of the concentrations measured during September show that the highest concentrations were the ones taken closest in time to September 11, closest in proximity to Ground Zero, and in the downwind direction. For example, five measurements of dioxin TEQs were over 100 pg TEQ/m 3 (all others were under 100 pg TEQ/m 3 ), and these were the first measurements in the three nearest downwind monitors: the first 3 measurements in the WTC Building 5 monitor on September 23 (160 pg TEQ/m 3 ), October 2 (170 pg TEQ/m 3 ), and October 4 (170 pg TEQ/m 3 ), the first measurement at the Church and Dey monitor on September 23 (130 pg TEQ/m 3 ), and the first measurement at the Liberty and Broadway monitor on September 23 (100 pg TEQ/m 3 ). While the highest dioxin measurements were found on September within and to the east of Ground Zero, three samplers to the west of Ground Zero showed background levels of dioxins on September 23. Similar trends were seen for other contaminants. It is reasonable to conclude that air concentrations within and very near Ground Zero would have been at least at these high levels and probably higher during the first several days after September 11. These areas were in restricted zones, which minimized overall exposures, and exposures were further minimized for individuals who used protective gear and clothing.

Occupational and Indoor Exposures : Extensive data sets are available from OSHA and NIOSH on occupational exposures on the Ground Zero site. Many of these samples were personal air monitors, and as such, are the most appropriate types of samples for evaluating inhalation exposures of workers. The contaminants evaluated in this report and many more are included in these data sets. The vast majority of samples in both data sets were below occupational standards including OSHA PELs a nd NIOSH RELs. The ATSDR has completed a study of residential apartments (NYCDOHMH/ATSDR, 2002). Testing occurred between November 4 and December 11, and included 57 apartments in lower Manhattan as well as 5 comparison apartments. In all tested apartments (lower Manhattan and comparison), airborne fibers were not detected above background levels in any of the indoor air samples. However, bulk dust samples showed asbestos in 16% of the apartments in Lower Manhattan, and none in the comparison apartments. Also, synthetic vitre ous fibers (SVF or fibrous glass) were found in both indoor and outdoor samples in Lower Manha ttan. Another study sampling indoor air and dust on September 18 in 2 locations very near Ground Zero found significantly high concentrations of asbestos in both air and dus t, but low, background, concentrations of dioxin, PCBs and metals.

## Exposure and Human Health Evaluation of Airborne Pollution from the World Trade Center Disaster

Section I. Overall Purpose and Scope of Assessment

The purpose of this docum ent is to provide a prelim inary assessm ent of the potential hum an health im pacts associated with exposures to em issions caused by the Septem ber 11, 2001, collapse of the W o rld Trade Center (W TC) towers. This assessm ent focuses on a disaster that has already occurred, and it becam e a challenge to evaluate the seriousness of health im pacts that

m a y have resulted (or m a y still result) from past exposures to contam inants. This situation presents problem s that are different from those faced in analyses to support the proactive establishm ent of environm ental standards, to determ ine em ission lim its from air sources, and in sim ilar regulatory venues where risk assessm ent procedures are used. In such circum stances, risk m a nagers can m a ke an active choice regarding the level of protection that is to be achieved and how uncertainties will be weighed in that process. In addressing exposures resulting from the W T C attack, those options are not available. Accordingly, this report attem p ts to take a practical, integrative approach to evaluating and conveying the potential im pacts and their seriousness from a public health perspective.

Six contam inants/contam inant classes were evaluated in this assessm ent. These included: particulate m a tter (PM), m e tals (lead, chrom i um , and nickel), polychlorinated biphenyls (PCBs), dioxins, volatile organic com pounds (VOCs; benzene and several others), and asbestos. Although hundreds of different substances have been m easured in various m e dia, these substances were selected for evaluation because m onitoring indicates that they correlate with the disaster site in both tim e and space, and because they pose a potential concern for health im pacts. PM was generated by the collapse of the W T C buildings, the recovery and dem o lition operations, and the lingering fire. Lead and asbestos were believed to be com ponents of the W T C building m a terials. PCBs were likely used as dielectric fluid in transform e rs and capacitors. Dioxin and VOCs are produced as a result of com bustion and volatilization f r om fuels. A screening of all substances was not possible in the tim e available. Instead, a judgem e nt

was m a de that the above listed chem icals m i ght pose the greatest health concerns. Other contam inants m a y be evaluated in later reports.

Potentially exposed populations could include anyone who lives or works in the vicinity of W T C, such as cleanup workers, office workers, m e rchants, or residents. Available data were not always sufficient to evaluate the potential im pacts to all populations from all contam inants. For exam ple, it was decided that m onitoring data for VOCs at Ground Zero could not be used to evaluate VOC exposure to Ground Zero workers. The reasons for this are twofold. First, m o st of the EPA data for VOCs at Ground Zero cam e from sim p le grab sam p les taken within plum es and within rubble piles. The principal purpose for this sam p ling strategy was to understand the

source em issions of VOCs from the W T C rubble and fires, and to alert the Fire Departm e nt of New York (FDNY) and the contractors/union h ealth/safety officers working at Ground Zero about conditions that posed im m e diate health concern to the workers. As such, these data were deem ed not appropriate for evaluating hum an exposure and potential health im pacts. Second, analyses of exposure of Ground Zero workers to VOCs were conducted by the Occupational

DRAFT--DO NOT QUOTE OR CITE 12 October 2002Saf e ty and Health Adm i nistration (OSHA) and the National Institute f o r Occupation Saf e ty and Health (NIOSH), who em ployed personal air m onito rs for their analysis. These m onitors are

m

u ch m o re appropriate for hum an exposure assessm ent. The OSHA data, as posted on their website (http://www.osha.gov), are sum m a rized in Section VI. The NIOSH data are also

sum m a rized there, with a reference provided for further inform ation (CDC, 2002).

On the other hand, an evaluation of Ground Zero worker exposure was conducted for dioxin-like com pounds. Unlike the case with VOCs, the dioxin m onitors were stationary highvolum e m onitors operating for 8-hour periods. High concentrations captured by these m onitors in the few m onths after Septem ber 11 are representative of air quality to which unprotected workers were potentially exposed (i.e, those not wearing respirators). Exposures to asbestos at the Staten Island Landfill were also evaluated using am bient air data. Although workers were not specifically identified as the exposed population, conservative assum p tions in an exposure and risk assessm ent suggest that even continuous exposure for the lim ited tim e period when asbestos at the Landfill m a y have been elevated would not have resulted in exposures that suggest a potential hum an health risk.

Exposures that were specific to the indoor environm ent were also not explicitly addressed in this assessm ent. Section VI describes com p leted and ongoing studies which have m easured levels of contam inants, m o stly asbestos, in indoor environm ents. A m a jor study com p leted by the Agency for Toxic Substances and Disease Registry (ATSDR) is sum m a rized in that section. Also, EPA Region 2 is currently conducting indoor m easurem ents during the clean-up of residences in lower Manhattan. Clearly, this will reduce future indoor exposures. It is expected that this EPA effort, and future com p ilations of all available indoor data, will allow for a m o re
com p lete evaluation of im pacts on residents and office workers to contam inants that were present as a result of the collapse of the W T C Towers.

This assessm ent focuses on the inhalation pathway. Exposure can potentially occur via inhalation, dust ingestion and derm al contact with contam inated dust on surfaces. Derm al contact and dust ingestion were not assessed due to a lack of appropriate data and reliable

m e thods. For residents, contacts with contam inated dust will occur m o stly indoors where people spend the m a jority of their tim e. The health assessm ent conducted in this study assum e d that

am bient air m easurem ents were representative of long- and short-term exposures. In som e cases, this could be m i sleading or inappropriate, partic ularly if indoor concentrations are higher than outdoor concentrations. It is em phasized that the evaluations in this docum ent focus on am bient, outdoor m easurem ents.
Because of the difficulties in setting up an effective m onitoring program in such circum stances, very little data for m o st chem icals were collected prior to Septem ber 18, 2001. As a result, exposures occurring on Septem ber 11 and during the week after are poorly characterized. It can reasonably be assum e d that the concentrations within and near Ground Zero would have been at least as high and m o re likely higher than the first m easurem ents taken near Septem ber 18. Section V reviews this hypothesis and dem onstrates that, for m a ny critical contam inants, the highest concentrations were the first ones taken. The individual contam inant

assessm ents address this lack of data in different ways. For dioxin, it was assum e d that the first concentrations m easured on Septem ber 23 were representative of the period between Septem ber

DRAFT--DO NOT QUOTE OR CITE 13 October 200211 and that first m easurem ent. For som e chem ical classes, like VOCs, an exposure and health evaluation for this tim e period cannot be conducted because the data do not exist. This could be critical for benzene, for exam ple, which could have been present at very high levels near Septem ber 11 due to volatilization f r om gasoline and aviation f u el. EPA-ORD researchers are working to use m odeling and available data and m e teorological inform ation to reconstruct probable exposures for som e contam inants such as PM. Som e prelim inary results of plum e dispersion are included in this report. Wh en this and other work on imm e diate post-Septem ber 11 issues has been com p leted, further health evaluations of this critical window m a y need to be conducted.

Sim ilarly, data regarding contam inant levels prior to Septem ber 11, or levels that m i ght be considered background and typical for New York City (NYC), do not exist for all com pounds because such m easurem ents have not been perform e d routinely in all urban areas. Wh ere inform ation specific to NYC is available, such data are discussed. Otherwise, general urban or general background concentrations are identified and used to place the post Septem ber 11

m onitoring results in perspective.

This assessm ent evaluates the potential for health im pacts from the exposures that have occurred from Septem ber through about April of 2002. Most m onitoring was discontinued in July of 2002, but data only through April was available at the tim e this evaluation was conducted. The air concentration data shows that, by April 2002, initially high levels decreased to background levels, with m o st reaching background by Decem ber 2001. However, the data collected between April and July, 2002, will be exam ined in the com i ng year to see if there were any elevations which could change the findings presented in this report.

As m o re data becom e available, further assessm ents m a y be conducted in order to evaluate m o re chem icals, m o re pathways, the indoor environm ent, the period between April and July, 2002, and other identified data gaps. Local and Regional needs, peer review and public

com m e nts on this assessm ent, and professional judgm ent will be used to determ ine the direction of future assessm ents.

DRAFT--DO NOT QUOTE OR CITE 14 October 2002

### Section II. Exposure Assessment and Risk Characteriz a tion Approach

Exposure assessm ents and risk characterizations for all contam inants focus on the inhalation pathway. For m o st chem icals, potential health risks are evaluated by com p aring the

m easured air levels at locations near Ground Zero to established benchm arks for inhalation exposure and to typical urban background levels. Occupational Safety and Health Adm i nistration (OSHA) Perm issible Exposure Lim its (PELs), National Institute for Occupational Safety and Health (NIOSH) R ecomm e nded Exposure Levels (RELs), and Agency for Toxic Substances and Disease Registry (ATSDR) Minim a l Risk Levels (MRLs) are am ong the benchm arks included in this evaluation. W h ere available, benchm arks established to protect against acute and subchronic exposures are used. Benchm arks that are intended to protect against exposures lasting m o re than one year or throughout a lifetim e, such as EPA’s Reference Concentrations (RfCs), were only used if other m o re appropriate benchm ark values were not available. Table 1 provides a summ a ry of the inhalation benchm arks used in this analysis.

EPA’s Region 2, in consultation with federal health agencies, also used benchm ark values to com p are with m easured air concentrations. These are described and listed in Appendix A, and are also cited on EPA’s W T C web site: http://www.epa.gov/wtc. Region 2 used existing standards where appropriate, and for other contam inants, developed unique standards specifically for the purpose of evaluating the air m easurem ent data from the W T C site. Som e of the existing standards which they used included occupational standards such as OSHA PELs, which were used for all site workers conducting response/dem o lition activities covered by OSHA, and environm ental standards such as National Am bient Air Quality Standards (NAAQS: e.g., for lead) and the Asbestos Hazard Em ergenc y Response Act (AHERA) level of concern for asbestos to evaluate m onitoring data from the site perim e ter and beyond where residents or nonW T C site workers m a y have been exposed. In cases where appropriate standards did not exist, the Region developed risk-based screening criteria. The risk assessm ent paradigm detailed in EPA’s “Hazard Evaluation Handbook: A Guide to Rem oval Actions” (HEH; EPA, 1997b) was

em ployed in the developm ent of these risk-based criteria. Screening levels that the Region developed reflect the m o st current toxicity criteria (Slope Factors and RfCs) on EPA’s IRIS database (http://www.epa.gov/iris). The Region developed benchm ark values for cancer and non-cancer effects. Details of the Region’s deri vation procedure are provided in Appendix A.

Som e of the benchm arks used by the Region were also used as benchm arks in this report, such as the AHERA standard, while others we re not. The unique benchm arks developed by Region 2 for evaluating W T C air m easurem ents were not used in this report. The Region needed to develop and utilize those benchm arks in order to provide daily data reports that were readily understandable. Only existing benchm arks were used in this report, and in som e cases, cancer or non-cancer screening exercises that went beyond a sim p le com p arison to a benchm ark were

em ployed (e.g., dioxin-like com pounds, see discussion below). Efforts are underway within EPA to develop benchm arks and sim ilar standards to evaluate the im pacts from a short-term inhalation exposure such as that experienced by som e individuals at the W T C site. One such effort entails the developm ent of Acute Exposure Guideline Levels. Final AEGLs are available for som e contam inants, such as vinyl chloride, m e thylene chloride, m e thyltrichlorosilane, and others, but finalized (or draft) AEGLs are not currently available for the contam inants evaluated in this report.

DRAFT--DO NOT QUOTE OR CITE 15 October 2002A sim p le com p arison of an air m easurem ent and a health benchm ark can be thought of as a “screening” exercise; the risk assessor is screening for possible problem s. If the m a jority of

sam p les are m u ch less than a benchm ark, then in m o st cases it would be appropriate to conclude that a health im pact is unlikely. On the other hand, if m o st sam p les exceed the benchm ark, then it m a y be appropriate to consider the possibility that a health im pact m a y have occurred, or could occur, depending on the circum stances.
For dioxin toxic equivalent (TEQ) exposures, the air m onitoring data are additionally used to conduct an assessm ent on cancer and noncancer risk. This involved defining the exposure scenario in greater detail, quantifying exposure within these scenarios for purposes of cancer risk estim ation, and m odeling the change in body burden over the exposure period for

non-cancer assessm ent. Sim p le cancer screening exercises are also conducted for PCBs and asbestos. Insufficient inform ation about the other chem icals precluded sim ilar m odeling. Wh ere the data allowed, the best possible screening approach appropriate to each chem ical class is used to evaluate potential health consequence from m easured air concentrations.

In order to characterize exposure and risks, it is necessary to characterize the duration of exposure. Imm e diately following the collapse of the W T C towers, the NYC Mayor’s Office of Em ergency Managem e nt restricted access to the W T C and surrounding sites. From Septem ber 11 through 14, this restricted zone included lower Manhattan south of 14 thStreet. Figure 1 shows the zones restricted after Septem ber 14. The areas in Figure 1 that are identified by a date show when those areas becam e accessible to the general public. Further details and additional

m aps can be found at, http://www.nyc.gov/htm l/oem /htm l/other/restricted_zones/frozen_zone_history_pdf_page.htm l

. Wh en a zone was restricted, all pedestrian and vehicular traffic was lim ited to em ergency

m a nagem e nt and rescue personnel and other credentialed people. Residents were not allowed to occupy hom es located in the restricted zones. Although som e people in certain areas m i ght have

com e and gone quickly (for exam ple, to collect pets), noone was living or spending a significant

am ount of tim e in these areas unless they were part of the rescue, recovery and cleanup operations. As of m i d-May, 2002, there were 15 residential buildings in the restricted zone.

As described below, the collapse of the W T C towers resulted in exceedences of screening benchm arks. However, m o st of these exceedences were in restricted zones and persons who live and routinely work in these areas were unlikely to have been exposed. Regardless of the level of contam ination that m a y be present, if there is no exposure there is no hum an health risk. In discussions below, the tim ing and location of all exceedences are identified, and it is noted whether the location was in a restricted zone at the tim e of exceedence. These restricted zones also influenced the developm ent of “exposure scenarios” that were used in som e of the contam inant-specific evaluations.

DRAFT--DO NOT QUOTE OR CITE 16 October 2002Table 1. Inhalation health risk screening benchm arks used in this assessm ent.

Agency Screening Benchmark D efinition

I. Short-Term Exposures

OSHA Perm issible Exposure Lim it (PEL) The m a xim um allowable exposure to a concentration of a substance in the air. PELs are set to protect workers and are based upon an 8-hr tim e-weighted average exposure. PELs are enforceable standards.

OSHA Short Term Exposure Lim it (STEL) A 15-m i nute tim e-weighted average that should not be exceeded at any tim e during a workday. STELs are enforceable standards.

ATSDR A cute inhalation Minim a l Risk Level (MRL) An acute MRL protects against exposures that m a y last 1 - 14 days. An MRL is defined as an am ount of chem ical that gets into the body (i.e., dose) below which health effects are not expected.

ATSDR I nterm e diate inhalation Minim a l Risk Level (MRL) An interm ediate MRL protects against exposures that

m a y last 15 - 364 days.

EPASTSC Provisional Subchronic Reference Concentration (RfC) The STSC subchronic RfC is the exposure level that is likely to protect hum ans from adverse health effects when exposed over a period not exceeding 10% of their lifetim e (usually assum e d to be 7 years). These values are only provisional guidance.

ACGIH T hreshold lim it value (TLV) A recom m e nded exposure lim it based on an 8-hour workday and a 40-hour work week.

NIOSH R ecomm e nded Exposure Level (REL) The m a xim um recom m e nded exposure lim it determ ined to protect workers.

EPA A sbestos Hazard Em ergency Response Act (AHERA) level of

concern This standard was developed to be applied to asbestos in schools. School children were not to be allowed back into an “abatem ent” area (an area where activities were undertaken to reduce air concentrations) until several consecutive readings were less than the AHERA standard.

DRAFT--DO NOT QUOTE OR CITE 17 October 2002Table 1 (cont’d).

Agency Screening Benchmark D efinition

EPA A ir Quality Index (AQI) The AQI provides reference points by which (a) to judge increasing levels of concern for potential health effects associated with acute exposures to air pollutants (e.g., particulate m a tter [ P M] ) f o r which short-term National Am bient Air Quality Standards (NAAQS) have been set and (b) to help guide the public and local governm e nt officials on actions to m i nim i ze unhealthy exposures.

EPA N ational Am bient Air Quality Standard (NAAQS) National air standards set by EPA (under the Clean Air Act) to protect against effects on public health and welfare of m a jor urban air pollutants, e.g., PM. Shortterm (24-hr) NAAQS for PM are m o re relevant here than are long-term (annual average) PM NAAQS.

II. Long-Term Exposures

EPA R eference Concentration (RFC) An estim ate of a daily exposure to the hum an population (including sensitive subgroups) that is likely to be without an appreciable risk of harm ful effects during a lif etim e.

EPA C ancer Slope Factor (SF) An upper-bound 95% confidence lim it on the increased cancer risk from a lifetim e exposure to an agent. The SF is used in conjunction with a dose term , such as the

am ount of a chem ical inhaled, to conservatively estim ate the potential f o r incurring cancer within a lif etim e as a result of that exposure.

EPA Unit Risk (UR) The UR factor is used to estim ate the upper-bound 95% confidence lim it on the increased cancer risk from a lifetim e of inhalation to a contam inant. It is derived starting with the SF f o r a contam inant and then

assum i ng a lifetim e of exposure (24 hr/day, 70 yrs). W h en using the UR, a concentration corresponding to a lifetim e average concentration should be used.

EPA M axim um Contam inant Level (MCL) The MCL is the highest level of a contam inant that is allowed in drinking water. It is an enforceable standard that is set considering health effects and assum i ng the best available treatm e nt technology, while taking cost into consideration.

DRAFT--DO NOT QUOTE OR CITE 18 October 2002Figure 1. Figure showing the shrinkages of the restricted zones in the vicinity of Ground Zero over tim e. For exam ple, the area below Canal Street was no longer prohibited after 9/14, and sim ilarly, the shaded area beneath Cham bers Street becam e available only after 9/27. [Figure extracted from m ap supplied by City of New York, Em ergency Mapping Center]

DRAFT--DO NOT QUOTE OR CITE 19 October 2002

### Section III. Environmental Monitoring

W ithin a m onth after the disaster, EPA’s Office of Environm ental Inform ation (OEI) began com p iling the m onitoring inform ation generated by various agencies and providing that inform ation directly to the public on the EPA web site: http://www.epa.gov/wtc. Environm ental

m onitoring data were m a de available on a daily basis. EPA also developed three “trend reports,” dated Novem b er 20, 2001; January 24, 2002; and May 1, 2002. Most of these data were m a de available to the EPA’s National Center for Envi ronm ental Assessm ent (NCEA) in an electronic form for purposes of this report. These three principal sources - the web site, the trend reports, and the electronic data base - represent com p ilations/interpretations of m u ch of the sam e data.

The sources of data that have been relied upon in the developm ent of this report are further described below.

• T he “EPA W T C m onitoring database” In the afterm ath of the W T C disaster,

m a ny organizations and agencies conducted sam p ling and m onitoring activities to assess environm ental im pacts. The New York City Departm e nt of Health and Mental Hygiene (NYCDOHMH) initially requested that these m onitoring organizations forward their results to them so they could be aggregated and m a de available for internal use by federal, state and local decision-m a kers. On Septem ber 25, 2001, NYC asked EPA to assist in the m a nagem e nt of these data by developing a database capable of tracking and reporting on the environm ental data. The Agency delivered on Septem ber 28, 2001, the EPA W T C MultiAgency Database that houses data from thirteen federal, state and private organizations (including EPA, the New Yo rk State Departm e nt of Environm ental Conservation (NYSDEC), and the New York City Departm e nt of Environm ental Protection (NYCDEP) who conducted environm ental m onitoring after the Septem ber 11 disaster. Roughly 95% of all data in the database are from either EPA or the NYSDEC. This database has been m a intained by EPA’s Office of Environm ental Inform ation and provided a clearinghouse and com p rehensive site for use by all governm e nt agencies responding to the disaster. The database was provided to the authors of this report in May of 2002, and at the tim e, was current as of m i d-April, 2002.

• E nvironm ental Data Trend Report W o rld Trade Center Disaster (EPA, 2002a)

. These reports have been developed by IT Corporation under contract to EPA’s Office of Solid W a ste and Em ergency Response. IT Corporation has com p leted reports dated Novem b er 20, 2001; January 24, 2002; and May 1, 2002. This latest trends report is current to April 24, 2002. These trend reports focus solely

on m onitoring data and are summ a ries prim arily of the data included in the EPA W T C m onitoring database.

• E PA web site. Most of the data in the EPA W T C m onitoring database have been

summ a rized for the general public on the EPA web site dedicated to inform ation on the W T C site (http://www.epa.gov/wtc).

DRAFT--DO NOT QUOTE OR CITE 20 October 2002• H istorical concentrations of m e tals, VOCs, PM, dioxin, PCBs, carbon m onoxide (CO), nitrogen dioxide (NO 2 ), and sulfur dioxide (SO 2 ) for the NYC area provided by EPA Region 2 and found otherwise in the open literature.

• A ir m onitoring datafor VOCs and PM that were not part of the EPA W T C

m onitoring data base were provided by the ORD National Exposure Research Laboratory (NERL) staff.

• R eports and data developed by non-EPA Agencies involved in sam p ling at the W T C site, who used the data for their individual purposes. These data sets are described when appropriate and include, for exam ple, the Occupational Safety and Health Adm i nistration (OSHA) Sam p ling Results Sum m a ry posted on their web site (http://www.osha.gov) on 8/15/02, the National Institute for Occupational Safety and Health (NIOSH) data base (CDC, 2002), and the Agency for Toxic Substances and Disease Registry (ATSDR) study of indoor residences (NYCDOHMH/ATSDR. 2002).

Appendix B shows a summ a ry of the m onitoring stations that provided air m onitoring data to the EPA W T C m onitoring database that is used in this assessm ent. Prior to the terrorist attack on Septem ber 11, air m onitoring stations for PM already existed at a num ber of locations in NYC, including lower Manhattan, upper Manhattan, Brooklyn/Queens, the Bronx, and Staten Island, as well as New Jersey. Following the disaster, EPA’s Environm ental Response Team set up m onitoring sites at various locations near the W T C. The strategy em ployed in positioning the various “alphabet” m onitoring sites was to place the m onitors at varying distances surrounding, but near, Ground Zero. These alphabet m onitoring sites are listed first in Appendix B. Pollutants that have been m easured at these locations include polycyclic arom atic hydrocarbons (PAHs), dioxins, asbestos, PCBs, m e tals, silica, and PM. The second m a jor set of m onitoring stations listed in Appendix B were established by NYSDEC. These sites have been designated by num bers to contrast with the alphabet sites. Generally, these sites were further from Ground Zero. Pollutants m onitored at these sites included particulates, VOCs, dioxins, asbestos, aldehydes, and particle size fractions. In addition, EPA’s National Exposure Research Laboratory (NERL) set up m onitoring at three of the alphabet sites (A,C, and K) and at site 16 where m onitoring generally for particulates (and m e tals), VOCs and particle size fractions was conducted. Finally, the New Jersey Departm e nt of Environm ental Protection assisted in the

m onitoring of asbestos at nearby locations in New Jersey

Laboratories contracted by EPA have conducted m o st of the pollutant analyses, but EPA laboratories have done som e of the analyses, including som e of the dioxin and particulate analyses. The EPA laboratories that have participated in this effort include NERL’s Hum a n Exposure and Atm o spheric Sciences Division (HEA S) in Research Triangle Park, NC, and the Region 7 Environm ental Services Division in Kansas City, KS.

Inform ation on the m onitoring procedures and the data includes several other details, such as dates of m onitoring, different m onitoring and analytical procedures, and other issues that are specific to the pollutants. These pollutant-specific issues are discussed in each of the pollutant sections. Also, each section includes a m ap showing only those sites where m onitoring

DRAFT--DO NOT QUOTE OR CITE 21 October 2002was conducted for the specific pollutant.

Meteorological stations were also established following the attack. Six stations were set up by the U.S. Departm e nt of Interior, and one station was set up by EPA. These m e teorological data, in conjunction with m onitoring data, are being used by EPA researchers to m odel and recreate the potential exposures that m i ght have occurred im m e diately after the collapse of the W T C buildings. Som e im portant prelim inary results of the m odeling efforts are presented in this report. The overall m odeling analysis, when com p lete, will be presented in f u ture EPA reports and assessm ents.

In addition to air sam p les, bulk dust, water, river sedim e nts, and drinking water sam p les were collected from sites associated with the W T C and surrounding areas to determ ine the degree to which the disaster m a y have caused contam ination of these m e dia. Sam p ling and analyses were conducted by various agencies, including but not lim ited to, EPA Region 2, the United States Geological Survey (USGS), NYSDE C, and the New York State Departm e nt of Health (NYSDOH). Between Septem ber 11, 2001, and January 14, 2002, m o re than 150,000

sam p ling results were reported for the W T C and other New York and New Jersey sites. Results were reported for over 500 substances (statistics from the second of three trend reports; the third is cited as EPA, 2002a).

Although the data generated since Septem ber 11 included results for air, bulk dust, water, river sedim e nts, and drinking water, the focus of this evaluation is on the air sam p ling, with

som e discussion of the bulk dust as it relates to asbestos and other contam inants. It should be noted that none of the drinking water sam p les were found to have concentrations that exceeded any of EPA’s Maxim u m Contam inant Levels (MCLs) for drinking water.

DRAFT--DO NOT QUOTE OR CITE 22 October 2002

### Section IV. Evaluation

A uniform approach to characterizing the im pacts of all pollutants is not possible because the available background data and screening benchm arks vary between com pounds. Sim ilarly, the relevance of these data for the circum stances of exposure following the W T C disaster also varies with the type of contam inant being evaluated. Wh en benchm arks are available for the circum stances at hand they provide a quantifiable approach for assessing the im pact of hum an exposure. Such benchm arks are used and described, as appropriate.

Background or pre-existing levels of environm ental contam inants provide an im portant reference point for describing the environm ental im pact of the destruction of the W T C. If the

m onitored levels for a pollutant after the disaster did not appreciably exceed values comm only found in New York or other urban settings, concerns about elevated health risks will be reduced. On the other hand, when contam inant levels are in excess of background, a careful evaluation of the potential health im pacts is warranted. Exceedence of background levels does not itself necessarily im ply that potential health risks exist. Also, for som e pollutants, background

m easurem ents m i ght at tim es show substantial levels and have associated health risks. Thus,

com p arisons with background levels need to be interpreted in light of the health risk data for the pollutants.

As discussed below, air concentrations and subsequent exposures after Septem ber 11 were generally elevated for each pollutant over a lim ited span of tim e. Measured concentrations for m o st air pollutants were reduced by the beginning of 2002. Many of the environm ental health criteria have been developed to address “chronic” exposures to contam inants that are present in the environm ent for years or decades. Exposure levels that exceed a chronic health reference level for a lim ited period would generally be less likely to result in adverse health effects. Wh ere available, this report has tried to use acute and sub-chronic screening standards. Wh en chronic screening standards are used, the relevance of the com p arison is discussed.

In this report, reference is m a de to OSHA health criteria for the protection of worker’s health. These criteria are valuable for the analysis of W T C data for several reasons. Criteria exist for m a ny com pounds, not all of which have established environm ental health criteria, and they address risks due to less than lifetim e exposures. However, there are lim itations in applying occupational criteria to evaluations of environm ental health risks. Occupational criteria serve to protect relatively healthy worker populations that would typically be less diverse than the general population (in term s of age and health status). Occupational criteria also apply for workday periods, with exposures ceasing during nonworking hours; environm ental exposures are typically m o re continuous. Finally, risk levels that have been accepted in occupational settings

m a y exceed those accepted for long-term environm ental exposures to the general population. For these reasons, EPA has not generally used occupational standards as a basis for environm ental health criteria.

It is im portant to reiterate that very lim ited data are available on the levels of exposure that occurred to individuals due to direct contact with the plum e of sm oke and dust generated by the W T C collapse on Septem ber 11. Such exposures would have been of lim ited duration, but levels of contam inants m a y have been significantly higher than those m easured in m onitoring

DRAFT--DO NOT QUOTE OR CITE 23 October 2002program s that have tracked exposures in New York since that tim e. This is an issue that warrants further exam ination. Also, the am bi ent m onitoring did not begin imm e diately on Septem ber 12. The earliest reported data are from asbestos m onitoring, which began on Septem ber 14. The dioxin m onitoring did not begin until Septem ber 23. It is highly likely that air concentrations within and near Ground Zero were highest during these first several days, but

m onitoring is unavailable to confirm that hypothesis. This issue is addressed in m o re detail in Section V, which observes that the highest concentrations were am ong the first ones m e asured. Many m onitoring program s and studies are currently under way to help us understand health outcom e s that have resulted from acute exposures on Septem ber 11 and the next several days. These studies are discussed in the final section of this report.

This report should be viewed as the first phase of an ongoing analysis, and the conclusions and findings cited below should not be considered the final EPA judgem e nt. At this point, the available data and analyses are still too prelim inary to support reliable quantitative predictions of potential hum an health risks. Although a com p lete quantitative evaluation of the health im pacts of the disaster m a y never be possible, f u ture EPA analyses will attem p t to develop m o re quantitative estim ates of risks and health impacts using additional exposurerelated data and possibly, the results of epidem iological studies that are currently underway. An overview of epidem iological studies that are underway is provided in Section VII.

Following are assessm ents on the individual pollutants.

IV.a. Particulate Matter Airborne particulate m a tter (PM) is a com p lex m i xture of inorganic and organic substances transported in air as solid particles or liquid droplets. PM in am bient (outdoor) air can typically be divided by size into two groups: fine particles (less than

- 2.5 μm diam eter) and larger, or coarse, particles (ranging from ~2.5 μm to 50 μm or m o re). Fine PM includes prim ary particles form ed by com bustion (including condensed m e tal and organic vapors), as well as secondary aerosols (form e d by gas-to-particle conversions). Coarse PM consists m a inly of earth crustal m a terials f o rm ed by natural erosion processes or by hum an activities such as driving on paved or unpaved roads, agriculture and m i ning operations, industry, and construction/dem o lition.

PM exposures and associated potential hum an health risks are addressed in this prelim inary analysis because the collapse of W T C buildings resulted in vast quantities of structural m a terials and building contents being crushed and pulverized into airborne particles in a wide range of sizes, including both fine and co arse particles. These particles, along with particles and gases em itted f r om burning jet f u el, aircraf tparts, and building debris, f o rm ed the im m e nse dust/sm oke cloud that rapidly spread across the NYC area and dispersed over hundreds of square m iles. Thus, PM air m onitoring was essential to help characterize potential health effects resulting from hum an exposure to the initial dust/sm oke cloud, particles produced by the ensuing f i res, and reentrained particles stirred up into the air during recovery activities and transport of debris away from the W T C site.

Airborne PM exposures are of concern for hum an health because they can be associated with a wide variety of adverse hum an health effects. Som e health im pacts could include

DRAFT--DO NOT QUOTE OR CITE 24 October 2002respiratory effects (such as lung inflam m a ti on and exacerbation of asthm a ) and cardiovascular effects (including exacerbation of preexisting chronic heart disease). As with exposures to other environm ental contam inants, potential health im pacts depend on PM concentrations and duration of exposure, as well as the size of the particles inhaled and m a ny other factors (including the age and health status of exposed individuals). Depending on age and health status, som e groups (such as infants and children, the elderly, and/orindividuals with preexisting cardiovascular or respiratory diseases) m a y be considered sensitive or susceptible populations to possible effects of PM exposure.

Particulate m a tter is one of six com m on, widespread air pollutants (the others are ozone, carbon m onoxide, nitrogen oxides, sulfur dioxide , and lead) for which EPA has set National Am bient Air Quality Standards (NAAQS). A NAAQS is an air quality standard, set under the Clean Air Act, that is designed to protect public health. In 1987, EPA set PM 10 NAAQS (150 μg/m 3 , 24-hour average, and 50 μg/m 3 , annual average, averaged over 3 years) to protect against health risks associated with inhalable particles (m ainly those < 10 μm diam eter) that can deposit in lower (thoracic) portions of the hum an respiratory tract. These health-related PM 10 particles include both fine particles < 2.5 μm diam eter (PM 2.5 ) and a subset of coarse particles larger than 2.5 μm but less than < 10 μm diam eter (PM 10-2.5 ). Af ter reviewing the scientif ic bases for PM NAAQS in 1996, EPA concluded that fine and coarse com ponents of PM 10 particles should be treated as separate classes of pollutants. Thus, EPA m oved in 1997 to set an annual PM 2.5 NAAQS (15 μg/m 3 , annual average, averaged over 3 years) to protect against both shortand long-term exposures and a supplem ental 24-hour average PM 2.5 NAAQS (set at 65 μg/m 3 ) to protect against unusually high peak levels to decrease health risks associated with fine particle exposures. The PM 10 NAAQS were retained to address risks related to coarse particles. As

m o re scientific evidence becom e s available, consideration m a y be given to setting PM standards for shorter averaging periods (< 24 hr).

Also, to provide real-tim e, day-to-day inform ation to State and local health officials and the public, EPA established an Air Quality Index (AQI) level of concern (LOC) f o r daily PM 2.5 am bient concentrations at 40 μg/m 3

. The AQI is m eant to provide reference points for judging levels of potential health concern and to guide actions by citizens or governm e nt officials to protect the health of the public, including susceptible groups. Thus, in order to m i nim i ze risk of potential health effects am ong highly susceptible individuals (e..g, the elderly over 65 yr old or individuals with preexisting chronic cardiovascul ar or respiratory disease), actions should be taken to reduce or avoid exposures of such persons to 24-hour PM 2.5 concentrations above 40 μg/m 3

.

IV.a.1. Air Quality Monitoring of Ambient Particulate Matter Mass/Composition At the tim e of the Septem ber 11, 2001, W T C attack, there were no m onitoring sites

m easuring am bient air PM 2.5 or PM 10 concentrations in the imm e diate vicinity of the W T C or surrounding neighborhoods in lower Manhattan, except for PM instrum e nts operating at the Canal Street Post Office about a half m ile north of the W T C. However, there were num erous New York State-operated PM sam p ling sites m onitoring am bient air PM concentrations at various other locations throughout the five boroughs of New York City (NYC), with m o st

m easuring PM 2.5 levels by Tapered Elem ent Oscillating Microbalance (TEOM) m onitors.

DRAFT--DO NOT QUOTE OR CITE 25 October 2002During the days following the Septem ber 11 events, substantial efforts were m a de to quickly augm ent existing PM m onitoring capabilities by the addition of PM sam p ling sites im m e diately around the W T C Ground Zero work zone and in surrounding lower Manhattan neighborhoods. Of particular note, staff from EPA’s National Exposure Research Laboratory (NERL) worked with EPA Region 2 colleagues to set up PM sam p lers at three surface sites triangulating the W T C Ground Zero work zone perim e ter, as shown in Figure 2 (lettered sites A, C, and K). Site A was located at Barclay and W

. Broadway just north of Ground Zero, Site C at Liberty and Trinity to the southeast of Ground Zero, and Site K at Albany and W e st to the southwest of Ground Zero. In addition to these surface sites, ORD PM sam p ling was initiated at the 16 thfloor level in EPA Region 2 facilities in the Federal Building at 290 Broadway about six or seven blocks northeast of the W T C. These sites are noted in Table 1 of Appendix B, as EPA Response Team Lettered Sites at Locations A, C, and K and Site #16 under EPA/ORD Num b ered Air Monitoring Stations. By Oc tober 2, the U.S. EPA Region 2 and EPA OAQPS, along with New York State Departm e nt of E nvironm ental Conservation (NYSDEC) personnel, set up PM instrum e nts at Cham bers Street, Park Row, and the Coast Guard Building at the Battery, which along with the existing m onitors at Canal St., surrounded Ground Zero a few blocks farther out than the ORD sites.

Measurem ents of am bient air PM 2.5 elem ental com position were m a de by ORD staff (Vette et al., 2002) at the three ORD surface sites (A, C, and K), using saturation sam p lers (SS), and on the 16 thfloor of the 290 Broadway Federal Building, using a m odified dichotom ous versatile air pollutant sam p ler (VAPS). The VAPS also collected PM 10-2.5 sam p les. Only the battery-powered saturation sam p lers could be operated within the W T C perim e ter because power outages precluded operation of conventional sam p lers, such as EPA Federal Reference Method (FRM) sam p lers in use at preexisting NY State-operated PM m onitoring sites. Although the SS has been shown (Hill, et al., 1999; also see http://www.airm etrics.com /products/studies/1.htm l ) to achieve accuracy within 6-10% com p ared to PM 2.5 FRM m easurem ents at concentrations typically found in am bient air, uncertainty in m easured PM 2.5 concentrations increase as am bient concentrations increase, especially above 100 μg/m 3 (24-h average). Indeed, even the FRM is subject to increasing uncertainties at high PM 2.5 levels. However, the general characterization of air quality used for EPA’s Air Quality Index (AQI) should be largely unaffected. The use of these sam p lers (SS) allowed f o r x-ray f l ourescent (XRF) analyses of the elem ental com position of

aerosol sam p lers. Such XRF analyses were perf orm e d on f ilters collected f r om Septem ber 21, 2001, to January 31, 2002. These sam p les were collected on an alm o st daily basis for sam p ling periods of about 22 hours per day. In addition to the VAPS sam p ler, high tim e-resolution

m easurem ents of light scattering by particles (which is related approxim a tely to the concentration of fine PM) and light extinction (which is related to the concentrations of black carbon and to com p lex organic com pounds such as PAHs) were also m a de. The m a in focus of discussion here with regard to EPA/ORD results is on f i ndings f r om f

ilter-derived PM m a ss and elem ental com position m easurem ents.

The ORD PM m onitoring sites triangulating the W T C Ground Zero perim e ter were placed so as to allow: (a) continuous tracking of PM 2.5 em issions from Ground Zero, useful for detecting any extraordinarily high-level PM 2.5 exposures to rescue/recovery workers and others operating within or imm e diately around Ground Zero; and (b) the determ ination of the physical/chem i cal com position of W T C-generated PM em issions from the sm oldering fires or

DRAFT--DO NOT QUOTE OR CITE 26 October 2002recovery operations, which could serve as a “W TC signature” for tracking the m ovem e nt of the W T C plum e and its potential im pacts on ground-level air quality in the NYC area. Along with the addition of several m o re New York State-operated PM sam p ling sites in lower Manhattan and elsewhere as part of an extended air m onitoring network set up by NYSDEC, the ORD 290 Broadway site helped to ensure reasonably good coverage (within feasibility constraints) of lower Manhattan neighborhoods surrounding the W T C Ground Zero work zone. In addition to the ORD m onitoring sites (A, C, K, and 290 Broadway), Figure 2 shows the location of New York State-operated PM 2.5 and PM 10 sam p ling sites.

This expanded m onitoring coverage greatly enhanced federal/state governm e nt capabilities f o r tracking trajectories of W T C-generated plum es, areas potentially af f ected by the plum es, and possible W T C-related PM exposures in the NYC area. For exam ple, notable PM increases at ORD Site A (on the W T C Ground Zero north perim e ter), coupled with PM elevations at the NYSDEC site at Cham bers St. and W e st St. about 5 blocks north of the W T C (labeled BMCC for Borough of Manhattan Com m unity College in Figure 2) and/or at the Canal St. Post Office would be indicative of a north erly trajectory of the W T C plum e and potential surface-level exposures of population groups in the vicinity of those m onitoring sites and interm ediate locations. Alternatively, m a rked increases PM levels at Site A, coupled with PM elevations at 290 Broadway and/or PS 64 (~ 2.5 km northeast of the W T C), would be consistent with a northeasterly W T C plum e trajectory. Also, any increases in PM levels at Site C, coupled with elevations at Park Row and/or preexis ting PM sites at PS 199, the Maspeth Library in Queens, or PS 274 in Brooklyn would be consiste nt with an easterly W T C plum e trajectory; whereas PM increases at ORD Sites C or K, al ong with PM elevations at Battery Park, would indicate a southerly plum e m ovem e nt. PM increases at m u ltiple ORD sites proxim a l to the W T C perim e ter and in several neighborhoods in various directions from the W T C could also conceivably occur under m e teorological conditi ons involving low wind speeds and therm a l stability conditions, producing low m i xing layer heights and a m o re well-defined W T C plum e traversing across lower Manhattan or other NYC areas. On the other hand, if PM concentrations at other sites across lower Manhattan or other areas in NYC tend to vary with each other (i.e., go up and down together) and are sim ilar in values, this would im ply that they are responding m o re to urban or regional background sources rather than to em issions from the W T C sites.

To aid in assessing the potential ef f ects of W T C-related air pollutants on air quality in NYC areas, ORD has also em barked on the m odeling of the dispersal of W T C Ground Zerogenerated plum es, based on prevailing m e teorological conditions (e.g., wind speed and direction). This includes: (a) initially, cla ssical Gaussian plum e m odeling, providing regionalscale hour-by-hour plots that roughly delineate the likely spread and direction of the W T C plum e, and (b) m o re recent initiation of detailed local-scale com putational fluid dynam i c

m odeling which is expected to provide im proved, detailed estim ation of the dispersal of

em issions from Ground Zero in the street canyons of lower Manhattan. Som e prelim inary results of the regional-scale plum e m odeling are discussed below and com p ared with PM m onitoring results for certain days of particular interest. It is im portant to note that the prelim inary results of the regional-scale m odeling prim arily allow the estim ation of the likely direction and width of the W T C plum e at particular tim es, but they do not alone enable one to conclude if or where the plum e m a y have touched down and resulted in surface-level increases in pollutant levels. They alone also do not allow one to conclude what th e PM concentrations would have been, only what

DRAFT--DO NOT QUOTE OR CITE 27 October 2002the estim ated dilution would have been relative to W T C Ground Zero concentrations. During periods when em issions from Ground Zero were low, any increases in concentrations within the plum e would also be low. Other inputs (e.g., evaluation of surface-level PM m e asurem ents at various sites and/or photos of the W T C plum e) ar e also needed to aid in characterizing likely occurrences of plum es affecting the surface and/or possible hum an exposures.
In addition to the above expanded EPA and New York State governm e nt PM m onitoring and m odeling efforts, num erous other investig ators (e.g., som e from other Federal governm e nt agencies, academ ia, and comm e rcial firm s or sponsored by nongovernm e ntal organizations) collected data aim e d at in estim ating likely PM exposures associated with the W T C attack and ensuing fires and recovery operations. Lim ited published reports from such studies are becom i ng available, and a few salient points from these reports are alluded to here. More thorough discussion of these and other reports that becom e available in the com i ng m onths will be included in any subsequent, fuller EPA/ORD evaluation.

One im portant set of newly available findi ngs are those reported by Lioy et al. (2002), based on work done cooperatively with EPA/ORD a nd also partly funded by NIEHS. Direct air

m easurem ents of the com position of W T C-gene rated airborne particles by EPA/ORD did not begin until Septem ber 21, 2001. Before that date, only bulk sam p les of settled dust were available for chem ical analyses. Lioy et al. (2002) m easured the m a ss of particles in several size ranges in the settled dust and analyzed their com position. Also, detailed chem ical analyses of fine fraction particles (< 2.5 μm diam eter) from settled W T C dust has recently been reported (McGee et al., 2002). Although the bulk sam p les do not provide direct data on am bient air PM concentrations, they do provide strong clues as to the likely com position of airborne PM in lower Manhattan and the size distribution of particles in the suspended dust imm e diately after the collapse of W T C buildings. Sm all am ounts of W T C-derived settled dust were also provided by New York University investigators f o r laborat ory toxicity testing by EPA scientists (EPA, 2002c; Gavett et al., 2002) in EPA/ORD’s National Health and Environm ental Effects Research Laboratory (NHEERL).

Also, in a cooperative U.S. Departm e nt of Energy (DOE)/University of California study,

m easurem ents of the size distribution of particles in 10 channels from 0.09 to 12 μm were m a de on the roof of the Federal Building on Varick Str eet, using the rotating drum im pactor developed at the University of California, Davis (Cahill et al., 2002). This Varick Street DOE site is about 2.0 km north of the W T C (see Figure 2). Sam p ling began October 2, 2001 and continued into Decem ber 2001. Elem ental analyses of sam p les collected approxim a tely every 3 hours were done by synchrotron radiation-induced X-ray em ission (SRIXE).

IV.a.2. Particulate Matter Air Monitoring/Modeling Results

1. Particulate Matter Mass Measurements and Plume Trajectory Plots The collapse of the W T C buildings and the associated f i res resulted in the initial dispersion of large quantities of various-size particles in the m a ssive dust/sm oke cloud that enveloped lower Manhattan. It is clear from Figures 3 and 4 (and other photographs) that the densest portion of the dust/sm oke cloud initially spread in all directions and im pacted m o st of lower Manhattan, especially below Cham bers Street. On the basis of the size classifications (by

DRAFT--DO NOT QUOTE OR CITE 28 October 2002gravim etric and aerodynam i c m e thods) of particles settled in dust collected Septem ber 16-17 at weather-protected sites just east of the W T C, Lioy et al. (2002) reported the largest m a ss concentrations in the settled dust to be due m o stly to particles > 53 μm diam eter (~ 51-64% of total m a ss) and 10-53 μm (~ 35-45% of total m a ss), followed by lesser percentages for 2.5-10 μm (0.3-0.4% of total m a ss), and < 2.5 μm (~ 0.9-1.3% of total m a ss) particles. Given the tendency of large coarse particles to settle out of the atm o sphere closer to their em ission source(s) than sm aller fine particles, it is likely that higher percentages of sm all coarse particles (> 2.5 but < 10 μm ) and fine particles (< 2.5 μm ) were m o re widely dispersed in the plum e of dust and sm oke that spread prim arily to the southeast over Brooklyn and to the south over New York Harbor during the first 18 to 24 hours after the collapse of the W T C buildings on Septem ber 11.

Figure 5 shows the results of initial plum e dispersion m odeling for Septem ber 11. The predom inant wind direction was to the south-southeast; and this direction continued well into the next day (Septem b er 12). As seen in Figure 5, the predom inant direction of the m odeled W T C plum e flow is to the southeast, based on wind directions and speeds indicated by black arrows in this figure. This is consistent with photo im ages, such as the one shown in Figure 6.

Although no direct m easurem ents of PM concentrations are available for nearby lower Manhattan areas during the collapse of the W T C, som e rough estim ates can nevertheless be

m a de of what concentrations m a y have been reached. The dust cloud was optically dense, as can be seen from the airborne im ages. Under such conditions, sunlight does not reach the surface, and visibilities are greatly restricted. Conditions such as these have been encountered in dust storm s and in the London sm og episodes of 1952 and 1962 (Elsom , 1992). During such conditions, PM concentrations could have been several m illigram s per cubic m e ter (m g/m 3 ), i.e., thousands of m i crogram s per cubic m e ter (μg/m 3 ).

Particles sm aller than 2.5 m i crom eters (fine particles) lim it visibility m u ch m o re effectively than larger (coarse) particles and under conditions usually found in the eastern United States, am bient air concentrations of fine particles are typically higher than those of coarse particles. As a result, under these conditions, visibility reductions are caused m a inly by fine particles. There are a num ber of sim p le f o rm ulas that relate visibility to the concentration of PM 2.5 , such as one from Stevens, et al. (1984):

0.5 (km

- m g /m 3 ) = Vis (km ) * C (m g/m 3 ) ( 1 )

where V is the visibility range (km ) and C is the concentration of PM 2.5 (m g/m 3 ). During the collapse of the W T C towers, visibilities were reduced to less than 100 m (about 1 city block) on

m a ny streets. If we assum e that visibility on streets in lower Manhattan af f e cted by the dust cloud (see Figure 3) was controlled by fine particles, then application of the above form ula indicates that PM 2.5 concentrations could have been about 5 m g /m 3 (5,000 μg/m 3 ). However, the collapse of the W o rld Trade Center towers m a inly produced coarse particles (Lioy et al., 2002), that, as m e ntioned above, are less effective than fine particles in controlling visibility. Thus, the values given above represent lower lim its on the abundance of total PM. It should also be noted that the above estim ate of visibility is based on the loss of contrast between light and dark objects. In m a ny streets, sunlight was blocked and, hence, total PM concentrations could have

DRAFT--DO NOT QUOTE OR CITE 29 October 2002been m u ch higher than the lower lim it given above, perhaps even approaching concentrations of condensed water vapor that are observed in dense fogs (i.e., thousands of μg/m 3 ).

Thus, individuals engulfed in the initial dust/sm oke cloud m a y have been exposed for several hours to concentrations of both fine and coarse inhalable particles anywhere in the range from m illigram s per cubic m e ter (> 1,000 μg/m 3 ) to perhaps hundreds of m illigram s per cubic

m e ter (> 100,000 μg/m 3 ). However, it does not appear that people outside the lower Manhattan area (except possibly very briefly for those on Governor’s Island or in Brooklyn Heights) experienced such extrem e PM exposures. This estim ation is based, for exam ple, on hourly PM 2.5 levels observed at several NYSDEC m onitoring sites (Figure 7) during Septem ber 11 to 13. Of m o st note, as seen in Figure 7, PM 2.5 concentrations at NYC sites generally rem a ined under 25 μg/m 3 during m o st of Septem ber 11 and 12. However, hourly PM 2.5 concentrations did increase to the 50-100 μg/m 3 range for a few hours on Septem ber 12 and 13 at PS 64, which is located about 2.5 km northeast of Ground Zero, and at PS 199, which is located in Queens several m iles east-northeast of Ground Zero. These PM 2.5 increases m o st likely reflected eastnortheast dispersal of not only windblown fine PM from settled dust but also probably of newly form ed fine PM generated by the intense fires (> 1000 °F) at W T C Ground Zero. This would be consistent with dispersal to the east-northeast of the W T C plum e, as indicated by the ORD

m odeled trajectory plotted for Septem ber 13 (shown in Figure 8). The increased hourly PM 2.5 levels at PS 64 and PS 199 (reaching 166 and 100 μg/m 3 at 9 a.m

. Septem ber 13) indicate that the W T C plum e likely briefly fum i gated the surface for a few hours at those and/or intervening locations during the m o rning of Septem ber 13.

Changes in wind direction later in the day on Septem ber 13 resulted in rotation of the W T C plum e back to a flow predom inantly to the south-southwest (m ainly over New York Harbor) through Septem ber 14 and 15, as indicated in Figures 9 and 10. Note the very low PM 2.5 hourly values (alm ost all < 6 μg/m 3 ) at NYSDEC m onitoring sites throughout the NYC area following rain associated with a frontal passage and, also, likely reflecting in part decreased vehicular traffic in the afterm ath of Septem ber 11 events.

During the next several days, ORD plum e di spersion m odeling indicates that the plum e rotated in such a m a nner as to result in transport in varying directions, including som e tim es to the north-northwest (over northern New Jersey and NYC areas), but there was little indication of the plum e fum i gating the surface, based on surface PM m easurem ents at preexisting PM

m onitoring sites. During the rest of Septem ber and on into October, 24-hour PM 2.5 values at preexisting NYSDEC m onitoring sites did not exceed the daily PM 2.5 NAAQS (65 μg/m 3 , 24-h). In fact, daily PM 2.5 values from m o st pre-existing fixed sites throughout the NYC area did not show m a rked elevations in com p arison to historical PM 2.5 levels f o r NYC areas, with the occurrence through m i d- to late October (from tim e to tim e or from site to site) of a few 24-hour PM 2.5 values approaching the 24-hour AQI LOC (40 μg/m 3 ) not being notably out of line with past frequency of such excursions in NYC.

Starting Septem ber 21, the EPA/ORD W T C perim e ter m onitoring sites at Sites A, C, and K (within 100-200 m e ters of Ground Zero) allowed tracking of W T C-related am bient PM

em issions in the imm e diate W T C vicinity. Th e ORD m onitoring data, shown in Figure 11 (top) showed widely varying PM concentrations across the W T C perim e ter sites from day to day, with

DRAFT--DO NOT QUOTE OR CITE 30 October 2002high hourly or daily PM 2.5 levels being seen at one or another perim e ter site downwind from Ground Zero on given days. As seen in Figure 11, exceedances of the 24-hour PM 2.5 NAAQS level (65 μg/m 3 ) occurred at som e Ground Zero perim e ter sites during late Septem ber and into October, but on only a few occasions thereafter. A general downward trend in daily PM concentrations, as well as a decreasing range of 24-hour variations, were seen for PM 2.5 concentrations at these W T C perim e ter sites from early October, 2001, onward. The range of 24-hour values am ong these ORD sites generally rem a ined below the AQI LOC of 40 μg/m 3 during Decem ber, 2001, and January, 2002 (as depicted by black bar in lower right of Figure 11 top panel). In contrast to the results seen f o r the ORD/W T C perim e ter sites, distinctly lower PM 2.5 concentrations were observed at the 290 Broadway site about six blocks northeast of Ground Zero. The 24-h PM 2.5 concentrations recorded there by VAPS sam p ling exceeded 65 μg/m 3 (daily PM 2.5 NAAQS level) only once, on October 4; and the 24-h AQI LOC (40 μg/m 3 ) for highly susceptible persons was approached or exceeded at the 290 Broadway site on only a few occasions (e.g., Sept. 27; Oct. 3, 4, 5; Oct 20; Nov. 15-16). These daily values often reflect high hourly values occurring overnight m a inly during early m o rning hours before 7 or 8

a.m

. The overall pattern of results from ORD perim e ter m onitoring stations near the W T C, coupled with distinctly lower PM 2.5 concentrations m onitored by ORD on the 16 thfloor at 290 Broadway (about 6 blocks northeast of the W T C) suggest occasional short-term increm ents in fine PM values at W T C Ground Zero and, at tim es, along the W T C fire plum e path (with areas im pacted shifting with prevailing winds).

For exam ple, when low wind speeds and m i xing layers associated with a high pressure system over New York City area occurred during October 3-5, generally increased region-wide PM 2.5 levels were observed across m u ch of northern New Jersey and New York City, with som e additional PM increm ents being superim posed at a few m onitoring sites within m odeled W T C plum e dispersion areas. During such weather c onditions, plum es tend to be m o re well-defined than if there were turbulence and are m o re identifiable for longer distances (see Stull 2000, for

exam ple). In particular, 24-hour PM 2.5 at W T C Site A (on north perim e ter of Ground Zero) reached 400 μg/m 3 on October 3-4, but 24-hour PM 2.5 values dropped off to 90 μg/m 3 at the 290 Broadway site several blocks northeast of W T C and to 53 μg/m 3 at PS 64 about 1.5 km further to the northeast of W T C Ground Zero and only reached 60 μg/m 3 at Site K (on southwest perim e ter of Ground Zero). This was consistent with prevailing winds (to the northeast) and the

m odeled plum e dispersion depicted in Figure 12 for October 4.

Daily average PM 2.5 data obtained at additional sites in lower Manhattan (Cham b ers St., Park Row, and the U.S. Coast Guard Station at Battery Park) are shown in the lower half of Figure 11. These sites are located from 3 to 10 blocks to the north, east, and south from the W T C (see Figure 2). It can readily be seen in Figure 11 that concentrations of PM 2.5 were m u ch lower than found at the W T C perim e ter, indicating a very rapid decline with distance from Ground Zero. PM 2.5 concentrations at these three sites can also be seen to go up and down together. Correlation coefficients between pairs of these sites are all > 0.9; and the concentrations are all very sim ilar, suggesting that these sites were responding m a inly to variations in urban and regional background sources rather than to W T C em issions. None of the daily PM 2.5 values exceeded the 65 μg/m 3 PM 2.5 24-hr NAAQS. Only a few daily PM 2.5 values, as seen in Figure 11 and listed in the W T C Environm ental Data Trend Report (EPA, 2002a) for the NYSDEC lower Manhattan sites to the north, east, and south of the W T C even approached

DRAFT--DO NOT QUOTE OR CITE 31 October 2002the 40 μg/m 3 AQI LOC value; m a ny of the 24-hour PM 2.5 levels for such sites were below 20 μg/m 3

. PM 10 values (not graphically depicted here) observed at the sam e NYSDEC lower Manhattan locations around the W T C were also consistently below the daily PM 2.5 NAAQS (150 μg/m 3 , 24-h) and showed a general decreasing trend from October 1 to Novem b er 30 and beyond, with 24-hour values decreasing from ~ 50-90 μg/m 3 at som e sites in early October to generally less than 50 μg/m 3 in Novem b er (except for ~114-135 μg/m 3 on October 25-26 for Park Row and 55-75 μg/m 3 on Novem b er 15-16, 2001 for all the sites).

Overall, then, the PM 2.5 data appear to support the following conclusions:

(1) Notable PM 2.5 elevations occurred in the im m e diate vicinity of the W o rld Trade Center Ground Zero during late Septem ber/early October, with concentrations at ORD W T C perim e ter sites on som e days exceeding the 24-hr PM 2.5 NAAQS. However, PM concentrations at the W T C perim e ter sites fell to typical background levels by late Novem b er/early Decem ber, 2001.

(2) Such high PM 2.5 elevations were not observed at other lower Manhattan m onitoring sites within 3 to 10 blocks of W T C Ground Zero. On only a few sporadic occasions did daily PM 2.5 concentrations approach or exceed the AQI LOC (40 μg/m 3 ) at one or two sites (e.g., 290 Broadway or PS 64) along the W T C plum e path in addition to elevations seen at W T C perim e ter sites. The frequency of such excursions were not out of line with historical frequency of PM 2.5 values approaching or exceeding 40 μg/m 3 either before the Sept. 11 W T C attack or since the W T C fires ended. See Figure 13, for exam ple, where post Septem ber 11 PM 2.5 24-h values for PS 64 are com p ared to historic levels seen at PS 64 during the previous two years.

(3) No notable elevations in PM 2.5 concentrations were seen at NYSDEC lower Manhattan sites located 3-10 blocks to the north, east, and south from the W T C, with no PM 2.5 values exceeding either the PM 2.5 daily NAAQS or the AQI LOC from the start-up of PM m onitoring on October 1 onward.

2. Measurements of Particle Composition Analyses of bulk sam p les of dust produced by the collapse of the W T C towers were perform e d by EOHSI at Rutgers University (Lioy et al., 2002). Two bulk dust sam p les were collected on Septem ber 16 and another on Septem ber 17. The sam p les were collected at weather-protected sites located less than 1 km to the east of the W T C. The particle sam p les were separated according to size by aerodynam i c and gravim etric m e thods. As noted earlier, results of the aerodynam i cally separated sam p les indicate that only a very sm all fraction (about 1%) of PM was in the PM 2.5 size range and less than 0.5% was in the PM 10-2.5 size range. The overwhelm ing fraction of the m a ss of PM was found in settled dust particles larger than 10 μm

. Most of the m a ss consisted of pulverized building and construction m a terials such as cem ent and glass fibers and office building m a terials such as cellulose. High concentrations of inorganic constituents such as silica, calcium , and sulfate com ponents of building m a terial and m e tals such as lead and zinc, were found. Also, total polycyclic arom atic hydrocarbons (PAHs), which are products of incom p lete com bustion, constituted m o re than 0.1% of the total m a ss of dust. The fraction of adsorbed PAHs in each size fraction is expected to be roughly related to the relative surface area in each size fraction. According to this criterion, sm aller particles would have contained proportionately greater concentra tions of PAHs than indicated by their relative

DRAFT--DO NOT QUOTE OR CITE 32 October 2002m a ss.
Lioy et al. (2002) provides com p lete descri ptions of num erous other specific com pounds that were found in dust particles that settled outdoors. They also noted that penetration of substantial quantities of W T C-derived dust into indoor office or residential spaces likely notably increased the potential for indoor exposures (via ingestion or by inhalation of re-entrained particles) to high levels of constituent elem ents and com pounds.

More detailed chem ical analyses have been perform e d on aerodynam i cally size-separated PM 2.5 derived from bulk dust sam p les collected on Septem ber 12 and 13 from several locations withing 0.5 m iles of Ground Zero (EPA, 2002c; McGee et al., 2002). These analyses showed that calcium sulfate (gypsum ) and calcium carbonate (calcite) were m a jor com ponents of the fine fraction, indicating that very finely crushed building m a terials were still dom inant com ponents even in this size range. Fine particles m o re easily penetrate into offices and residential spaces and thereby contribute to indoor exposures m o re readily than coarse particles.

Data for EPA/ORD m easurem ents of PM elem ental com position of fine particles (PM 2.5 ) for sam p les collected starting Septem ber 21 are gr aphically depicted in Figures 14 to 18. The elem ents are grouped in each figure roughly according to their relative abundance in the subject air sam p les, those in Figures 14 to 16 being am ong the m o st abundant and those in Figures 17 to 18 being distinctly less abundant. Most of the elem ents shown in the figures were well correlated (r > 0.85) with each other at individual sites, with several being m u ch m o re highly correlated (r > 0.95) with each other and with PM 2.5 throughout the sam p ling cam p aign. The very high correlations suggest a comm on source origin for these elem ents, that is, W T C fires. The com position of the em issions from Ground Zero com bustion sources changed with tim e as evidenced by initial peaks in several elem ents (e.g., calcium , potassium , sulfur, chlorine, brom ine, lead, copper, and zinc) during late Septem ber and early October (Figures 14 to 16), followed by later peaks in the concentration of chrom i um , arsenic and antim ony during m i d- or late Novem b er (Figures 17 and 18). The elem ents for which data are depicted in Figures 14 to 18 were selected f o r illustration f r om a larger set m easured by ORD, based on evident elevations of their concentrations over typical background levels at som e point during the sam p ling

cam paign.

Consistent with Lioy et al.’s finding of highl y enriched calcium in both fine and coarse f r actions of settled dust near the W T C, m a rkedly increased levels of calcium continued to be seen in airborne fine particles (Figure 14) at ORD’s Ground Zero perim e ter sites off and on throughout Septem ber and October and m u ch of Novem b er, decreasing to low background levels by late Novem b er. Elevated levels of calciumin the fine fraction are indicative of highly pulverized building m a terials (e.g., wallboard) from the W T C site. However, except for a few occasions (e.g., on October 6), airborne fine PM calcium levels were not m a rkedly elevated above background levels at the EPA 290 Broadway site a few blocks northeast of Ground Zero, whereas calcium in the PM 10-2.5 coarse fraction (not graphically depicted here) did show rather frequent elevations at the 290 Broadway site but decreased to low background levels by the end of Novem b er.
Fine PM silicon elevations were only evident brief l y during October 3-5 at Location A

DRAFT--DO NOT QUOTE OR CITE 33 October 2002and at the 290 Broadway site, in contrast with coarse (PM 10-2.5 ) silicon elevations (generally in the 1000-3000 ng/m 3 range) seen at 290 Broadway on a num ber of days well into late Novem b er. The coarse fraction calcium and silicon enri chm e nts m o st likely reflect (a) windblown re-entrainm e nt of calcium and silicon-contam inated dust rem a ining on rooftops or window ledges, for exam ple, after hazardous m a terial cleanup of W T C-derived dust in lower Manhattan during the two weeks after Septem ber 11, and/or (b) calcium and silicon particle re-entrainm e nt into am bient air associated with W T C recovery operations and transport of debris away from Ground Zero.

Data for concentrations of elem ental carbon and total organic com pounds in the aerosol phase based on analyses of paired f ilter sam p les are not yet available. However, ORD nephelom e ter results and the results of analyses of bulk dust com position m e ntioned below suggest that the W T C em issions contained substantial quantities of carbon produced by incom p lete com bustion. Surprisingly low total carbon levels (1.5 to 8.5%) were found in aerodynam i cally size-separated PM 2.5 sam p les from the bulk dust sam p les collected on Septem ber 12 and 13 (McGee et al., 2002). These results indicate that crushed building

m a terials were the dom inant sources of fine PM imm e diately after the collapse of the towers, whereas com bustion from ongoing fires was a relatively m o re im portant source of PM 2.5 in later

em issions from the W T C disaster site. Potassiumenrichm e nts were also especially notable for ORD Site A m easurem ents into early October (consistent with com bustion of organic m a terials such as wooden furniture, paper, etc.); but m u ch lower potassium concentrations occurred at 290 Broadway, and air levels of potassium at all ORD sites returned to very low background levels by late Novem b er.
Elevations of sulfur, chlorine, and brom ine (shown in Figure 15) were clearly evident at ORD Ground Zero perim e ter sites and som e tim es at 290 Broadway during late Septem ber and decreasingly so into October, again consistent with the notable enrichm e nts seen by Lioy et al. in W T C dust particles. The sulfur was likely in oxidized form , som e perhaps having been converted from prim ary em issions of SO 2 into secondary sulfate particles, consistent again with both reports of elevated sulfate levels in settled W T C dust particles (Lioy et al., 2002; McGee et al., 2002) or airborne particles (including very fine fraction particles) collected at the DOE Varick St. site on October 3 (Cahill et al., 2002). Also consistent with the Lioy et al. findings of chlorine and brom ine enrichm e nts in W T C settled dust are ORD m easurem ents of unusually elevated chlorine and brom ine at Ground Zero perim e ter sites. The W T C sources of these halides are not clear, but chlorine from burning plastics is not unlikely. The specific enrichm e nt in fine particles of chlorine (versus m o re typical sodium chloride present as coarse particles) and no notable sodium enrichm e nt rule out attribution of the chlorine levels sim p ly to airborne sea salt inf l uxes into the W T C f i re site.

As seen in Figures 16-18, lead and certain other m e tals (copper, zinc, antim ony, palladium , and cadm i um ) were notably elevated on som e days in late Septem ber and into early October at EPA/ORD Site A, as com p ared with concentrations at Sites C and K, but the concentrations of these m e tals had generally decreased to background levels by m i d-October. The late Septem ber/early October elevations at Site A on the W T C north perim e ter indicate that the W T C fires were likely a comm on source of em issions of these m e tals, because the winds

were m a inly from the southwest at this tim e. The detection of elevated levels of arsenic and

DRAFT--DO NOT QUOTE OR CITE 34 October 2002antim ony in m i d-Novem b er at ORD Site K on the southwest perim e ter of Ground Zero (but not at Sites A or C or at 290 Broadway to the nort h, northeast, or southeast of the W T C) suggests both a different source of W T C fire em issions and a likely clim atic shif t to winds f l owing m a inly from the north/northeast to the south/southwest. The chrom i um elevations seen around Novem b er 20, m a inly at Site C, suggest possibly yet another later shift in the com position of Ground Zero sources of W T C-generated airborne particle em issions. Hence, the “W TC signature” appears to have varied over tim e in term s of its specific elem ental com position.

In contrast to the above patterns of elem ent levels which indicate that they m a y have originated from the W T C fires, the gradually increasing concentrations of nickel up to a range sustained during Decem ber and January (after the W T C fires were out) seem to argue against any notable airborne fine-particle nickel em i ssions from the W T C fires subsequent to the collapse of the W T C buildings on Septem ber 11. Still, enrichm e nts in sam p les of settled dust from sites east of the W T C (Lioy et al., 2002) are likely indicative of nickel having been am ong the m e tals present in high concentrations of airborne particles in the initial dust/sm oke that enveloped lower Manhattan on Septem ber 11. This raises the possibility of (a) any rem a ining nickel-containing dust being re-entrained into outdoor air during later rescue/recovery operations and/or (b) continued elevations of nickel concentrations in W T C-derived indoor dust and re-entrained indoor air particles.

3. High Temporal Resolution Analyses The ORD PM 2.5 and associated elem ent m easurem ents discussed above were obtained

over sam p ling periods of close to 24 hours. Exam ination of additional data is necessary to determ ine m o re precisely the duration and nature of enhanced concentrations of PM constituents and to help understand possible public health im pacts of such excursions. For exam ple, of m u ch interest are PM elem ental com position data for the period October 3-5, when a high pressure system settled over New York during the early m o rning hours of October 3 and 4. Concentrations of sulfur were close to six tim es higher at the downwind ORD W T C site (Site A) than at the upwind site (Site K) on October 4. Concentrations of a num ber of other elem ents were also m u ch higher by large enrichm e nt factors at Site A as com p ared to Site K, as indicated by the enrichm e nt f actors (noted in parentheses) f o r the f o llowing elem ents: silicon (41X), chlorine (500X), potassium (47X), calcium (5 X), brom ine (350X), copper (130X), zinc (110X), palladium (> 100X), cadm i um (>100X), antim ony (>100X), and lead (66X). Overall, the above results are m o st consistent with brief, episodic increases from W T C Ground Zero during early

m o rning hours on October 3 and 4 leading to elevated concentrations of PM and its constituent elem ents at W T C perim e ter sites and one or another sites in lower Manhattan located downwind of the W T C on those days (i.e., to the north and/or northeast). These enhanced concentrations were superim posed on generally higher concentrations of PM and its constituents found upwind of the W T C on those days. The higher concentrations found at the upwind sites were associated with a high pressure system that settled over the New York Metropolitan Area during that period. In any case, the results suggest strongly that the W T C site was the dom inant source of these elem ents on October 3-4.

University of California, Davis m easurem en ts (Cahill et al., 2002) on the roof of the DOE building indicate a sharp increase in concentrations of PM 2.5 , m a inly in the size range between 0.34 to 0.56 μm on the m o rning of October 3, as shown in Figure 19. This very brief excursion

DRAFT--DO NOT QUOTE OR CITE 35 October 2002only lasted a few hours. Concentrations of sulfur and silicon at this tim e were notably elevated at the DOE site as com p ared to days imm e diatel y before and after. Also, ORD data collected by both the nephelom e ter and the aetholom eter sited on the Federal Building at 290 Broadway indicated substantial elevations of PM and light-absorbing com ponents within the space of a few hours early in the m o rning of October 4. Hourly PM 2.5 levels at PS 64 were also elevated (som e in excess of 100 μg/m 3 ) during or shortly after the sam e hours on October 4, suggesting brief surface fum i gation by the W T C plum e to the north-northeast of Ground Zero.

It has been suggested that the high concentrations of sulfur observed at the DOE building on Varick Street were related to transport from power plants either in the Northeast or in the Ohio Valley. During this early October period, there were m o st probably som e increases in the concentration of sulfur associated with regional scale transport of sulfates derived from distant

sources. However, the extrem ely high abundance of sulfur at Site A on the Ground Zero perim e ter observed by ORD and the ratio of sulfur observed at Site A com p ared with that observed at Site K suggests that Ground Zero was a large source of sulfur on October 3 and could have also contributed to sulfur readings at the DOE rooftop site.

The peak elevations of airborne f i ne PM silicon lim ited to October 3-4 at Site A and at 290 Broadway are notable, suggesting high tem p erature volatilization of silicon from glass and/or cem ent by intense W T C fires on those dates and transport of the W T C plum e in a north to northeasterly direction. This is consistent both with the plum e trajectory plotted in Figure 12 and the m a rked increases in silicon levels reported by Cahill et al. (2002) at the DOE Varick Street site, to the north-northeast of the W T C, including unusual m easured elevations of silicon in very fine (0.09-0.50 μm ) and, possibly, inferred ultrafine (< 0.01 μm ) PM size ranges (silicon otherwise typically being m a inly associated with coarse fraction particles > 2.5 μm ). There were also m a rked increases in ORD-observed concentrations of various m e tals on October 3-4, reinforcing the conclusion that the DOE Varick Street data for October 3 reflected em issions from intense Ground Zero fires. The very brief increase in PM 2.5 values and high levels of silicon at the DOE site on October 3 apparently did not occur again at that site, based on prelim inary EPA evaluation of the Cahill et al. raw data provided by DOE (Figure 19). Interestingly, Lioy et al. (2002) reported lead a nd other substances as being unusually congealed together with silicon in particles f r om the W T C settled dust, likely due to the vaporization of silicon, lead, and/or other m e tals by intense heat, followed by their condensation and coagulation into particles with unusual com position.

The above high-resolution m easurem ents suggest that W T C em issions in late Septem ber and early October varied greatly at tim es over 24-hour periods and that som e of the m o re notable

em issions probably occurred in discrete events which resulted in air pollutant elevations that lasted only a few hours (m ainly overnight during cooler early m o rning hours before tem p erature increases af ter sunrise). Such events were likely related to activities of rescue and recovery operations at the W T C, such as rem oval of large pieces of debris perhaps resulting in increased oxygen flow and brief flareups of fires within the W T C rubble pile. Further high tem poral resolution analyses, including m o re detailed local-scale W T C plum e plots, will be needed to better understand the specific lower Manhattan areas im pacted by short-term W T C em ission events and the im plications of these sporadic events for potential hum an exposures and health im pacts.

DRAFT--DO NOT QUOTE OR CITE 36 October 2002IV.a.3. Evaluation of Potential Particulate Matter Human Exposures and Health Impacts

Because no direct m easurem ents were obtained for airborne particle concentrations present in the dense dust/sm oke cloud that enveloped lower Manhattan for up to about 4 hours after the collapse of the W T C buildings on Septem ber 11, estim ates of likely exposures to airborne PM for individuals caught in the initial dust/sm oke cloud can only be deduced from indirect evidence and are subject to great uncertainty. Nevertheless, several tentative conclusions appear to be warranted on the basis of available inputs thus far.

First, it is likely that m a ny persons caught outdoors (or som e even indoors) in the initial dust/sm oke cloud were exposed for several hours to extrem ely high levels of airborne particles. This exposure probably included inhalation of PM concentrations in the m illigram s per cubic

m e ter range, well in excess of 1 to 2 m g /m 3 (1000-2000 μg/m 3 ), for both fine (PM < 2.5 μm diam eter) and coarse (PM > 2.5 μm ) inhalable particles. Although there were no m easurem ents available during this critical tim e period, an exam ination of available photographs in

com b ination with an em pirical relationship based on visibility suggests that concentrations could very easily have been this high and likely were even m u ch higher (e.g., possibly > 5 m g /m 3 ). Such a finding is also supported by analyses of bulk dust sam p les conducted by Lioy et al. (2002).

The coarse inhalable particles (PM > 2.5 μm ) likely included substantial quantities of particles in the PM 10-2.5 range, which are capable of reaching lower respiratory tract (thoracic) regions of the lung, even though such coarse particles m a de up less than 0.5% of the particles found in W T C-derived settled dust by Lioy et al. (2002). Individuals who inhaled such high concentrations of W T C dust particles, even for a few hours, would logically be expected to be at potential risk for imm e diate acute respiratory a nd other sym p tom s and/or, possibly, m o re chronic health im pacts associated with lung deposition of notable quantities of constituent PM m a terials (e.g., calcium , silicon, potassium , lead, other m e tals).

Persons exposed to the very high PM levels in the initial dust cloud and who continued to work at Ground Zero or returned to work there within a few days without wearing adequate protective respiratory gear m i ght be at especially increased risk for potential acute or chronic health effects, depending on the extent of any ensuing exposures to high PM levels on or imm e diately around the Ground Zero rubble pile. The latter could include additional exposures to coarse PM constituents (e.g., calcium or silicon) present in re-entrained dust particles from the initial W T C building collapse and/or exposures to newly form ed fine particle constituents (e.g.,

m e tals), as well as to organic constituents (e.g., PAHs present in both size ranges) em itted from the W T C f i res.
Evaluation of potential health im pacts associated with the above types of PM exposures should be further facilitated by disease registry efforts and retrospective epidem iologic analyses of physician/em ergency departm e nt visits and hospital adm i ssion records being sponsored by the Centers for Disease Control (CDC), the Agency for Toxic Substances and Disease Registry (ATSDR), the National Institute of Environm enta l Health Sciences (NIEHS), and other f e deral, state, and NYC agencies and that are now under way. Recent reports (Prezant et al., 2002)

DRAFT--DO NOT QUOTE OR CITE 37 October 2002indicate that large percentages of firem e n caught in the initial W T C dust cloud and others who worked at Ground Zero during the first 2 to 7 days post Septem ber 11 experienced respiratory (e.g., “W TC cough” and/or bronchial hyperactivity) or other sym p tom s that still continue to persist for som e individuals several m onths after cessation of exposures at W T C Ground Zero.

During the week following Septem ber 11, the plum e from initial high-intensity W T C fires appears to have been largely convected upwards and dispersed m a inly to the south-southeast or south-southwest without m u ch evident ground level contact, except perhaps for a few hours on the m o rnings of Septem ber 12 and 13, when it flowed to the east-southeast of the W T C. This resulted in briefly increased hourly PM 2.5 levels at sites in lower Manhattan (166 μg/m 3 at PS 64 on 9/13) and in Queens (100 μg/m 3 at PS 199 on 9/13). Probably few people were exposed around the PS 64 site, given the restrictions in e ffect on m o tor vehicular or pedestrian traffic below 14 thStreet until Septem ber 14, but som e m a y have been briefly exposed in the vicinity of the PS 199 site and/or at locations between the two sites. Although it is doubtful that the brief, several-hour PM 2.5 excursion on the m o rning of Septem ber 13 resulted in harm ful PM exposures, retrospective exam ination of physician and em ergency departm e nt visits and/or hospital records in the affected areas m a y help to verify this.

After Septem ber 21, EPA/ORD m onitoring indicated initially high levels of W T C-derived airborne particles (especially at certain Ground Zero perim e ter sites) during late Septem ber and early October, but occurrences of PM excursions decreased over tim e through late October and into Novem b er. The rate of decrease in concentrations was not uniform throughout the

m onitoring period; rather, there were episodes of high PM levels spaced between periods of

m

u ch lower concentrations. The frequency of the episodes was highest during the first m onth following the collapse of the W T C buildings and then declined afterwards. For exam ple, notable PM em ission episodes occurred during the first m onth of sam p ling, as shown in Figure 11. PM 2.5 concentrations varied over a wide range (som etim es exceeding the relevant AQI 40 μg/m 3 action level) during late Septem ber and early Octobe r at EPA/ORD W T C perim e ter Site A. The concentrations of a num ber of elem ents m easured at this site also showed large day-to-day variability, as shown in Figures 14-18. On a num ber of days in late Septem ber and early October, concentrations of several elem ents were m a ny tim es higher than the m o re typical background levels recorded for Decem ber-January, after the W T C fires had largely or entirely burned out.

On the basis of overall air quality results summ a rized above, it appears that 24-hour PM 10 and PM 2.5 values throughout m o st all of the NYC m e tropolitan area generally rem a ined at or returned rather quickly to historical background levels and W T C PM em issions posed no increased health risks beyond those due to usual PM levels for m o st areas of NYC. On the other hand, high PM 2.5 concentrations recorded on the perim e ter of Ground Zero during late Septem ber and early October m a y im ply increased health risks for the m o st highly exposed individuals (that is, persons who spent extended periods of tim e within the W T C Ground Zero work zone without wearing protective respirators). Specifically, acu te exposures to irritating m a terials present in either the PM 2.5 or coarse particle com ponents of PM 10 , especially during any high hourly peak excursions, m a y have contributed to acute or continuing respiratory sym p tom s reported by som e workers and/or residents in lower Manhattan areas in the imm e diate W T C vicinity. It is m u ch less likely that any m a rkedly increased health risks were posed by am bient air PM exposures

DRAFT--DO NOT QUOTE OR CITE 38 October 2002elsewhere in the lower Manhattan neighborhoods surrounding the W T C, although m o re thorough analysis and m odeling of potential PM exposures and correlation with health records is needed to evaluate this issue m o re f u lly.

It m a y be useful to place the above potential airborne PM exposures in perspective by

com p aring them to (a) exposures that occurred during som e past notable PM air pollution episodes and (b) m o re recent historical data recorded for New York City areas. As discussed in U.S. EPA (1982, 1986a) and Elsom (1992), a num ber of past severe air pollution episodes involved extended periods of exposure of urban populations to high concentrations of airborne PM and associated air pollutants such as SO 2 . In contrast to relatively brief periods (< 8 hours) of Septem ber 11 inhalation exposures on Septem ber 11, 2001 to concentrations in the range of, and m a ybe in excess of, 1000-2000 μg/m 3 of W T C-derived airborne coarse and fine PM, a

num ber of past air pollution episodes in U.S. cities (e.g., Donora, PA in 1948; NYC in 1953 and 1962/63) and internationally (e.g., Neuse Valley, Belgium
, 1930; London, UK in 1952, 1957, 1963) involved exposures to very high levels of PM that lasted for at least several days. Probably the m o st fam ous such episode occurred in London in Decem ber 1952, when m illions of Londoners were exposed to daily PM levels (m easured as British Sm oke, which included high percentages of fine particles) of 1000-4000 μg/m 3 (som etim es reaching hourly peaks of 6000 μg/m 3 or m o re) on 3 to 5 consecutive days in the presence of 1000-4000 μg/m 3 of SO 2 . In NYC, PM 2.5 values recorded on som e days at the Ground Zero perim e ter and occasionally elsewhere in lower Manhattan during late Septem ber and early October clearly exceeded the m o re usual background levels of fine PM seen in NYC since im plem entation of the PM NAAQS in the 1970s began to substantially reduce am bient PM concentrations in U.S. urban areas. For exam ple, som e ORD W T C perim e ter site 24-hour PM 2.5 m easurem ents of m o re than 100 μg/m 3 likely exceeded m o st - but not necessarily all - values recorded at the New York University Medical Center in an aerosol sam p ling study conducted in August 1976 (Lippm an, et al. 1979), as per the m ean value shown for PM 2.0 sam p les in Table 2. However, the 24-hour PM 2.5 concentrations (predom inantly below 30-40 μg/m 3 ) usually seen during m o st of the rest of October and into Novem b er at ORD W T C perim e ter sites were notably lower than the 1976 values; and the PM 2.5 levels reached by Decem ber and January generally com p are favorably with PM 2.5 values obtained at a m onitoring site at the Bronx Botanical Gardens during February-June 2000. This Bronx site can be considered to be a relatively “clean” urban background site largely free of the effects of strong local sources. Maxim u m PM 2.5 values ranged from 35.4 to 43.3 μg/m 3 from three inter-com pared collocated sam p lers at that Bronx site and average 24-hour PM 2.5 values ranged from 12.5 to 15.6 μg/m 3 , analogous to the m ean PM 2.5 concentrations shown in Table 2 for Boston and Philadelphia during February-June, 2000. Also, PM 10 values for lower Manhattan sites, which were m a inly in the range of 50-90 μg/m 3 during October and m o stly below 50 μg/m 3 in Novem b er, were not m a rkedly differe nt from historical values observed in NYC. For exam ple, the fourth highest and the m a xim u m 24-hour PM 10 values reported in the EPA Aerom e tric Inform ation Retrieval System (AIRS) database for the five NYC boroughs during 1996 to 2001 ranged from 40-89 μg/m 3 and from 51-121 μg/m 3 , respectively.

During Septem ber-October, 2001, concentrations of m a ny elem ents, including heavy

m e tals, at Ground Zero perim e ter sites were at tim es m u ch greater than those observed at several sites in the Northeast in February-June 2000. As part of a pilot study for EPA’s PM 2.5 speciation

DRAFT--DO NOT QUOTE OR CITE 39 October 2002network, concentrations of PM 2.5 and a num ber of key elem ents were m easured from February to June, 2000, in NYC (at the Bronx Botanical Gardens), Boston, and Philadelphia, at sites that were likely characteristic of urban backgrounds. As shown in Table 2, the average concentrations of PM 2.5 and the individual elem ents m easured at the three sites varied relatively little in contrast to those m easured near the W T C site. The highest m easurem ents of PM 2.5 and heavy m e tals are also shown in Table 2 for com p arison. During the first weeks after Septem ber 11, PM 2.5 levels and concentrations of several elem ents often were m a ny tim es higher than those obtained at the northeastern sites listed in Table 2. As also seen in Table 2, concentrations recorded at the New York University Medical Center in 1976 (Bernstein and Rahn, 1979) were higher than those at the other Northeastern sites, but they were still distinctly lower than the

m easurem ents m a de soon after Septem ber 11.

During Decem ber and January, the concentrations of m o st of the elem ents m e asured by ORD decreased to levels sim ilar to those m easured at the northeastern sites, suggesting that the W T C was no longer a significant source of these elem ents. However, it should be noted that even the m a rkedly elevated elem ent concentrations over typical background values noted m a inly in Septem ber and October did not exceed appli cable OSHA PEL (8-hour tim e-weighted average) values or other m o re broadly applicable health benchm ark values, suggesting a generally low health risk for those working at Ground Zero or others present in lower Manhattan neighborhoods around the W T C.

Alkalinity of the dust from the W T C disaster m a y have been a possible health concern for exposed individuals. Som e reported sym p tom s (eye, nose, and throat irritation; nose bleeds; cough) m a y have been due to exposure to unusually elevated quantities of certain crustal

m a terials derived from pulverized concrete, wa llboard, and other W T C structural com ponents present in airborne particles and settled dust in neighborhoods near the W T C. The United States Geological Survey (USGS, 2002). Lioy et al. (2002), and McGee et al. (2002) all reported testing aqueous solutions of W T C settled dust and f i nding an initially high alkalinity (generally

$ pH 10.0), which decreased to pH 8-9 for outdoor sam p les taken after rainfall (as reported by USGS). Because m u ch of the outdoor settled dust was rem oved by hazardous m a terial cleanup procedures or was washed away by rainfall duri ng late Septem ber, outdoor exposures to highly basic PM com ponents would seem to be of m u ch less potential health concern beyond late Septem ber when restricted zone shrinkages allowed m o re people and traffic in neighborhoods imm e diately surrounding the W T C work zone. However, USGS noted higher alkalinity for dusts

sam p led indoors, raising the possibility of greater risk of acute irritation sym p tom s being associated with indoor exposures to W T C dusts than with outdoor dusts leached by rainfall.

Lioy et al. (2002) m o re broadly highlighted indoor exposures to W T C-derived dust PM as posing potential increased health risks. Indivi duals visiting, residing, or working in buildings not adequately cleaned before reoccupation could have been subjected to repeated, long-duration exposure to m a ny of the com ponents from the original W T C collapse found by Lioy et al. in settled dust to the east of the W T C. Lioy et al. noted that long, narrow glass fibers in the W T C-derived dust had various potentially toxic m a terials attached to them and could contribute to acute short-term irritative effects and possibly to m o re chronic health risks.

Also of potential concern would be any extende d indoor air exposures to finely pulverized

DRAFT--DO NOT QUOTE OR CITE 40 October 2002building m a terials (e.g., calcium , silicon, iron, and sulfate) in PM particles, to PM of either fine or coarse size containing m a rked elevations of certain m e tals, or to fine PM containing usual

com b inations of silicon coagulated with m e tals or other toxic m a terials. Lioy et al. directed notable attention to indoor dust loadings of lead as posing potential chronic health risks. The possible contributions of certain other m e tals (e.g., nickel, chrom i um ) found in settled dusts or airborne PM to irritative sym p tom s also need further evaluation. The discussions below for lead, nickel, and chrom i um contain m o re inform ation on the possible bases for concern with these particular m e tals. The issue of potentially greater toxicity being associated with unusually increased quantities of very f i ne or ultraf ine particles present in airborne PM also needs to be evaluated further.

Som e newly available findings from the labor atory toxicity studies of W T C-derived dusts

m a y offer insights into potential health responses associated with exposures on Septem ber 11 to W T C-derived m a terials in the initial W T C building collapse dust cloud and later exposures to W T C-particles deposited indoors. ORD NHEERL scientists analyzed chem ical and toxicological properties of PM 2.5 derived from the collapsed W T C buildings (EPA, 2002c; McGee et al., 2002; Gavett et al., 2002). Deposited dust sam p les were collected from sites within a half-m ile of Ground Zero on Septem ber 11 and 12 and size-separated to collect the PM 2.5 fraction. Gavett et al. (2002) evaluated responses of young adult fem a le m i ce to bolus doses of W T C-derived PM 2.5 dusts adm i nistered by intratracheal instillation directly into the lungs and to 5-hour inhalation exposures to W T C PM 2.5 . On the basis of the overall pattern of results obtained, Gavett et al. observed both a sm all degree of pulm onary inflamm a tion in response to W T C dust, which was distinctly less com p ared with exposure to residual oil fly ash (ROFA), and som e notable increases in airway hyperresponsiveness to m e thacholine, a nonspecific bronchoconstricting agent, greater than that observed in m i ce exposed to ROFA or other PM sam p les. These effects m a y be interpreted as being consistent with reports of airway hyperresponsiveness and irritant responses in people exposed to high concentrations of W T Cderived dusts. Wh ereas the m ild pulm onary inflam m a tion in m i ce dim i nished from 1 to 3 days after exposure, the airway hyperresponsiveness appeared to persist longer.

These results suggest possible lim ited, short-term lung inflamm a tion effects from exposures to high concentrations of W T C dust (as m a y have occurred m a inly on Septem ber 11) or possible long-term airway hyperresponsiveness that m i ght portend m o re prolonged sensitivities and irritative sym p tom s for persons experiencing extended high-level exposures to W T C-derived dusts indoors. Gavett et al. (2002) estim ated the hum an exposure equivalent of the doses that led to these responses in m i ce, and calculated an 8-hour exposure at m oderate activity level to a concentration of 425 μg/m 3 using a m u ltiple-path particle deposition m odel (Ferijer et al., 1999). Individuals who are especially sensitive to inhalation of dusts, such as asthm a tics, m i ght experience these effects at lower concentrations over m o re prolonged periods of exposure. As m e ntioned previously, it is likely that persons caught in the initial dust/sm oke cloud could have been exposed to PM 2.5 concentrations in excess of 1000 μg/m 3

. However, a dose equivalent to a hum an exposure of 130 μg/m 3 over 8 hours caused no significant effects in the m i ce, suggesting that m o st healthy people would not be expected to respond to this

m oderately high exposure level with any adverse respiratory responses (EPA, 2002c; Gavett et al., 2002).

DRAFT--DO NOT QUOTE OR CITE 41 October 2002These studies did not address the effects of the coarse fraction of W T C PM on responses in

m i ce, which m a y be very im portant, considering the upper airways responses and ocular irritant effects that have been reported.

DRAFT--DO NOT QUOTE OR CITE 42 October 2002Table 2.Concentrations (maximumand Sept-Oct average) of PM2.5and Component Elements Measured at the EPA/ORDWorld Trade Center Perimeter Sites and at Four Other Sites in the Northeast U.S. (PM2.5concentrations in μg/m3; all othercomponents in ng/m3).WTC Max. (Site, Date)WTC Average Sept-Oct1NYU Med. Ctr.2Bronx, NY3Boston, MA3Phila,PA3ACKAug '76Feb-June '00Feb-June '00Feb-June '00PM2.5400 (A, 10/4)85345081.7412.510.714.7Na870 (A, 10/4)2731571695707217863Mg490 (K, 11/13)10167791034.8167.7Al670 (A, 10/20)198741131879.22518Si20000 (A, 10/4)9432243337592118S23000 (A, 10/3)479618082524682012009331500Cl45000 (A, 10/4)72475408451199.8687.7K5600 (A, 9/22)988147260194383860Ca4900 (A, 10/11)1304345749385057Cr34 (C, 11/19)543280.30.51.1Fe9400 (K, 12/12)17459049754009176103Co24 (A, 10/3)4bdlbdl3.20.40.4Ni50 (K, 12/11)1191118122.84.4Cu2800 (A, 9/22)43559922.82.24.5Zn10000 (A,10/4)1526164307224219.716As1100 (K, 11/14)9bdlbdl31.10.91Br5700 (A, 9/20)800821241332.52.53.4Pd900 (A, 10/4)13227Cd150 (A, 9/22 & 10/4)33997.71.71.71.8Sb350(A, 9/22)5021113.62.43.5Pb5500 (A, 9/22)7918316711704.23.45.61A time series of PM2.5measurements for Site A (as well as Sites C, K, and 290 Broadway) can be seen in Figure 11.Timeseries measurements for theDRAFT--DO NOT QUOTE OR CITE43October 2002elements in PM2.5fromthe samesites can be seen in Figures 14-18.Measurementsin these tables are the high measurements seen in these figures, and thedates of the measurements are shown in parenthesis.Nearly allelevated measurements were seen in Site A, and in late September, early October.bdl =below detection limit and n.a. = data not available.2NY Summer Aerosol Study, 1976.3Coutant et al., 2001.4PM2.00.9*PM2.5(estimated).DRAFT--DO NOT QUOTE OR CITE44October 2002ACKPS64•DOE•KeyforORDLettered SitesA= Barclay andWest BroadwayC= Liberty andTrinityK = Albany& West(as noted onfigure)Figure 2.Particulate matter monitoring sites, including ORD surface sites (A, C, K) on the WTC perimeter, the ORD site at 290Broadway, and NYSDEC sites located elsewhere..DRAFT--DO NOT QUOTE OR CITE45October 2002Figure 3. Spread of dense dust/sm oke cloud over all of lower Manhattan and drifting to the E/SE imm e diately after the Septem ber 11, 2001, collapse of the W o rld Trade Center buildings.

Figure 4. W o rld Trade Center (W TC) plum e from intense fires (>1000 °F) during days following Septem ber 11, 2001, with high concentrati ons of both newly form ed fine particles from com bustion and reentrained coarse particles likely being transported upward by convection processes and being dispersed in the W T C plum e over varying NY City areas, depending on prevailing wind directions and speeds.

DRAFT--DO NOT QUOTE OR CITE 46 October 2002Figure 5. ORD-m odeled W T C Plum e Dispersion on Septem ber 11, 2001 at 12 noon. The values indicated by red num erals are hourly PM 2.5 concentrations (in μg/m 3 ) m easured at pre-existing NJ and NY State-operated PM m onitoring stations in northern New Jersey and New York City. Red, orange, and yellow shading represent m o st likely areas of plum e dispersion (red = estim ated dilution to 100 thto 500 thand dark blue = dilution to < one m illionth of pollutant concentration at W T C source.

Figure 6. Satellite photograph of the W T C plum e lofting from Ground Zero at 11:43 a.m

. EDT on Septem ber 12, 2001. Note the very concentrated vertical convection of dust/sm oke particles upwards and the flow in a well-defined plum e towards the S/SE. ( Source: Mandatory credit:

“ s paceim a ging.com ”.)

DRAFT--DO NOT QUOTE OR CITE 47 October 2002Figure 7.Increased hourly PM2.5concentrations measured on September 12 and/or 13 at PS 64, PS 199, Maspeth Library, and PS274 to the E/SE of WTC, reflecting dispersal of newly formed fineparticles fromWTC fires and/or fine particles reentrained fromthesettled dust frominitial collapse ofWTC buildings.(PM2.5data provided courtesy of NYSDEC).DRAFT--DO NOT QUOTE OR CITE48October 2002Figure 8. ORD-m odeled W T C plum e dispersion for Septem ber 13, 2001 at 9:00 a.m

. Note the increased hourly PM 2.5 concentrations depicted in red for PS 64 (166 μg/m 3 ) and PS 199 (100 μg/m 3 ) NYSDEC m onitoring stations, consistent withthe E/NE direction of the m odeled plum e dispersion and likely touchdown of the plum e at those and intervening sites but not at sites further E, SE, or to the N.

Figure 9. ORD-m odeled W T C plum e dispersion on Septem ber 14, 2001 at 12 noon, indicative of plum e flow m a inly out over New York Harbor.

DRAFT--DO NOT QUOTE OR CITE 49 October 2002Figure 10. Satellite photograph of W T C plum e lofting from GZ at 11:54 a.m

. EDT on Sept. 15, 2001, and dispersing to the S/SW out over the New York Harbor. ( Source: Mandatory credit:

“ s paceim a ging.com ” .)

DRAFT--DO NOT QUOTE OR CITE 50 October 2002Figure 11. Panel A (top) : Daily PM 2.5 concentrations m onitored by EPA/ORD at sites A, C, and K around Ground Zero perim e ter and at 290 Broa dway 6 blocks northeast of Ground Zero. Panel B (bottom) : PM 2.5 concentrations observed at several extended m onitoring network sites in lower Manhattan within 3 to 10 blocks of W T C Ground Zero.

DRAFT--DO NOT QUOTE OR CITE 51 October 2002Figure 12. ORD-m odeled W T C plum e dispersion on October 4, 2001 at 3:00-4:00 a.m

. Note the general regional elevation of hourly PM 2.5 levels (in μg/m 3 ) indicated by red num erals for

m onitoring sites scattered across both northern New Jersey and NYC areas, even outside

m odeled areas of likely greatest plum e intensity indicated by red shading.

DRAFT--DO NOT QUOTE OR CITE 52 October 2002Figure 13. Daily PM 2.5 concentrations recorded at NYSDEC PS 64 m onitoring site after Septem ber 11, 2001 (9/11/01 to 10/27/01) com p ar ed to historic record of 24-hr PM 2.5 values at the sam e site during prior 2 years (2/23/00 to 9/01/01). Note exceedence of 40 μg/m 3 AQI Level of Concern on Septem ber 13 and likely again on October 4; red portion of bar indicates 24-hr average if three high hourly values (> 100 μg/m 3 ) being evaluated f o r data quality are included in 24-hr average calculation.

DRAFT--DO NOT QUOTE OR CITE 53 October 2002Fig ure 14. ORD m easure m ent of PM 2.5 ele m ental constituents Ca, Si, and K at Ground Zero peri m e ter sites and 290 Broadway site.

DRAFT--DO NOT QUOTE OR CITE 54 October 2002Figure 15. ORD m easurem ents of PM 2.5 elem ental com position for S, Cl, and Br at Ground Zero perim e ter sites and 290 Broadway site.

DRAFT--DO NOT QUOTE OR CITE 55 October 2002Figure 16. ORD m easurem ents of PM 2.5 elem ental constituents Pb, Cu, and Zn at Ground Zero perim e ter sites and 290 Broadway site.

DRAFT--DO NOT QUOTE OR CITE 56 October 2002Figure 17. ORD m easurem ents of PM 2.5 elem ental constituents As, Pd, and Sb at Ground Zero perim e ter sites and 290 Broadway site.

DRAFT--DO NOT QUOTE OR CITE 57 October 2002Figure 18. ORD m easurem ents of PM 2.5 elem ental constituents Ni, Cd, and Cr at Ground Zero perim e ter sites and 290 Broadway site.

DRAFT--DO NOT QUOTE OR CITE 58 October 2002Figure 19. PM 2.5 concentrations recorded on roof top of DOE Facility at Varick St., approxim a tely 2.0 m iles N/NE of Ground Zero. Note single very high PM 2.5 excursion m a inly restricted to m o rning hours of October 3 (see in set figure for October 3), consistent with ORD

m easurem ents at Location A on the W T C north perim e ter and ORD W T C plum e plot shown in Figure 12 for October 3.

DRAFT--DO NOT QUOTE OR CITE 59 October 2002IV.b. Metals

IV.b.1. Lead Lead, a silver-grayish sof tm e tal with a relatively low m e lting point, was still widely used in the 1960s and 1970s (when the W T C was built) in paint and for soldering indoor plum bing joints and electrical wiring system s. It was also used for soldering of com puter circuit boards and wiring in a variety of electrical appliances. These uses m a ke it likely that lead would be

am ong the toxic substances of concern at the W T C site. Lead could have been em itted as a

com bustion product of the ensuing fires or could have been present in reentrained particles stirred up into the air in the course of recovery activities and transport of debris away f r om the W T C site.

The potential public health concern due to lead exposure m o st relevant for consideration in relation to the W T C situation is lead intoxication associated with prolonged low-level lead exposures. As discussed in EPA (1986b), such exposure can result in subtle, often subclinical, health effects such as altered calcium m e tabolism and bone form ation/loss, slowed physical growth, and slowed nervous system developm ent of the fetus. Effects on the fetus m a y be due to exposure of the m o ther during pregnancy, therefore, wom e n of childbearing age have been identified as an im portant susceptible population. Other effects of lead intoxication m a y be slower postnatal growth and neurobehavorial deve lopm ent, IQ decrem ents and learning deficits, and other neuropsychological effects am ong young infants and children (another susceptible group).

In 1978, the EPA NAAQS for lead was set at 1.5 μg/m 3 (90-day average). This level was set to reduce the risk of occurrence of lead in toxication impacts associated with prolonged lowlevel exposures of susceptible groups. W ith the EPA phase-down of lead as an additive in gasoline during the past several decades and the current widespread use of unleaded gasoline in the U.S., am bient air lead concentrations have decreased dram atically. Before the start of the phase-down of lead in gasoline in the late 1970s, air lead levels as high as 2.0 μg/m 3 or m o re were often detected in U.S. urban areas such as NYC. Currently, 24-hour am bient air lead levels below 0.5 μg/m 3 are typical of NYC and other U.S. urban areas. NYSDEC Annual Air Quality Reports, for exam ple, indicate (a) arithm e tic m ean annual-average 24-hour airborne lead levels during 1994 - 1998 of 0.04 to 0.08 μg/m 3 for a Manhattan (Madison Ave.) curbside sam p ling site (m axim um daily value = 0.34 μg/m 3 ) and (b) arithm e tic m ean annual-average values ranging from 0.02 to 0.09 μg/m 3 for three Brooklyn/Staten Island sites (m axim um daily value = 0.63 μg/m 3 ) during 1992 - 1997.

Before the start of gasoline lead phase-out, lead concentrations in outdoor dust were reported (in studies assessed in EPA, 1986b) to range from 280 to 1500 μg/g (ppm ) in residential areas of NYC and Philadelphia and from 900 to 13,000 μg/g in street dust or near heavily traveled roadways in several northern U.S. urban areas (NYC; Philadelphia; W a shington, DC; Chicago; Detroit). Despite significant decreases in air lead concentrations, soil and street dust lead concentrations in excess of 500 - 1000 μg/g were still observed into the early 1990s in U.S. urban areas (e.g., Boston, Baltim ore, and Cincinnati, as described in EPA, 1996). This m a y reflect, in part, the residuum from earlier gasoline lead deposition from air or m o re current contam ination from deterioration of lead-based pa int from residential or other structures or from

DRAFT--DO NOT QUOTE OR CITE 60 October 2002industrial production or waste disposal activities.

The potential for very high short-term lead exposures existed during the initial spread of the dust/sm oke cloud from the initial W T C collapse; and the ensuing fires, recovery operations, and debris rem oval m a y have also posed som e lead exposure risks. Exam ination of air lead data from ORD W T C perim e ter sites (Figure 16) and for additional lower Manhattan sites (Figure 20) reveals that 24-hour lead concentrations within (e.g., at W T C Building 5 SW ) or at the W T C Ground Zero perim e ter (e.g., at Location A, Barclay and W

. Broadway; Location B, Church and Dey) approached or exceeded 1.5 μg/m 3 on several days in late Septem ber/early October (e.g., Septem ber 17, 23, 27 and October 4, 5). There appeared, however, to be rapid fallout (deposition) of the lead from air close to the W T C rather than the lead being transported over longer distances. This interpretation is based on the relatively uniform low air lead values (m ostly less than 0.5 μg/m 3 ) seen at the EPA ORD 290 Broadway m onitoring site (Figure 16) and at several other locations within a few blocks of the W T C (Figure 20). Consistent with the pattern seen in Figure 16 for EPA/ORD W T C perim e ter and 290 Broadway m onitoring sites, lead elevations at other lower Manhattan sites outside the W T C work zone generally returned to

m o re typical low background concentrations by m i d-October. After October 8, none of the air lead concentrations shown by the W T C Trends Report (EPA, 2002a) for any of the lower Manhattan m onitoring sites outside W T C Ground Zero approached or exceeded 1.5 μg/m 3 ; in fact, with very few exceptions, nearly all were below 0.5 μg/m 3 . Thus, prolonged lead concentrations averaged over 90 days during late Septem ber to late Novem b er, 2001, at W T C perim e ter or other nearby lower Manhattan sites did not exceed the EPA Lead NAAQS (i.e., 1.5 μg/m 3 , 90-day average). The overall pattern of data, coupled with restrictions of vehicular or pedestrian traffic in lower Manhattan areas close to Ground Zero until very late Septem ber/early October, m a ke it doubtful that persons outside the Ground Zero area were exposed sufficiently to airborne lead levels so as to experience any chronic health risks.

There m a y, however, exist som e basis for potential concern with regard to short-term (hours, days) highly elevated lead exposures of individuals working within the Ground Zero perim e ter without appropriate respiratory prot ection. The highest 24-hour lead level shown in Figure 20 was 5.4 μg/m 3 at W T C Building 5 on Septem ber 24. It is likely that com p arable or higher elevations in am bient air m a y have occurred within Ground Zero on som e days preceding the start of EPA m onitoring in late Septem ber. This possibility and the above-noted data showing air lead values approaching or exceeding 1.5 μg/m 3 on certain days during late Septem ber and into October at sites within the W T C work zone or at perim e ter sites very close to Ground Zero (within 100 - 200 m ) suggest that flare-ups of Ground Zero fires or lead

em issions associated with recovery and debris rem oval operations m i ght have posed risks for individuals within the W T C Ground Zero perim e ter. The potential risks would probably be of

m o st concern for pregnant wom e n or other wom e n of childbearing age if any were working within Ground Zero without wearing appropriate protective respirators for extended periods during the first 2 to 4 weeks after Septem ber 11. OSHA data ( http://osha.gov/nycdisaster/m ap.htm l ) do indicate that high air lead levels were detected on Septem ber 22 (69.3 μg/m 3 , averaged over 4.5 hr) and Septem ber 23 (18.1 μ g/m 3

, averaged over 3 hr) by area

m onitoring near W T C Building 5 well within the Ground Zero work zone. However, none of the OSHA personal sam p ling data reported for W T C recovery workers (e..g, ironworker, torchcutter/burner) exceeded the OSHA Lead PEL (50 μg/m 3 , 8-hr average) during late

DRAFT--DO NOT QUOTE OR CITE 61 October 2002Septem ber/m i d-October (although som e personal sam p ling results were reported that exceeded PEL levels on widely-scattered days from late October into early 2002 for the W T C 5 Building area at Ground Zero). Nor were there any notable blood lead elevations (m axim um values < 20 μg/dl) am ong m o re than 300 m a le fire fighters serving at W T C Ground Zero and sam p led by CDC in October 2001 (personal comm unication, P. Edelm a n). These data tend to suggest that, although it can not be entirely ruled out, it is unlikely that any pregnant or other wom e n of childbearing age working within the W T C Ground Zero perim e ter (e.g., am ong rescue/recovery personnel or assisting with dispensing of food, be verages or other aid to such personnel) would have experienced sufficient lead exposures to be at high risk for lead intoxication effects on them or any fetuses in-utero during or soon after W T C-related lead exposures.

It should also be noted that lim ited lead results available for analyses of bulk dust sam p les taken at locations close to the W T C did not appear to show any notably high lead concentrations. The values for bulk dust sam p les near the W T C noted in the W T C trends report ranged from 120 to 370 μg/g (ppm ) - the latter value for a sam p le taken at Park Place and W e st Broadway on Septem ber 16. These values are consistent with lead concentrations found by ORD in bulk dust near the W T C (m edian 142 ppm ) or those reported by cooperating academ ic investigators (Lioy et al., 2002) as ranging from 101 to 625 μg/g in bulk dust collected several blocks east of the W T C within days after Septem ber 11. They are also not exceptional in com p arison with the 500 - 1000 ppm street dust or residential soil lead concentrations often still found in U.S. urban areas in the 1990s, as earlier stated. However, as Lioy noted, indoor exposures to lead-contam inated W T C-derived dust that penetrated indoors could continue to pose risks to individuals re-occupying buildings not cleaned by effective decontam ination procedures.

On the basis of results evaluated to date, there is little indication of any substantial health risks being associated with lead exposures of the general population in lower Manhattan areas around the W T C site. However, evaluation of blood lead levels and pertinent m e dical records for any pregnant wom e n exposed at Ground Zero or in its im m e diate vicinity during Septem ber or early October could provide useful further data by which to assess any such possible health risks associated with W T C-generated lead em issions.

DRAFT--DO NOT QUOTE OR CITE 62 October 2002Figure 20. Am bient air lead concentrations (μg/m 3 ) at sites within Ground Zero or in lower Manhattan locations in imm e diate vicinity of the W T C.

Source: EPA Region 2

DRAFT--DO NOT QUOTE OR CITE 63 October 2002IV.b.2. Chromium and Nickel Chrom i um and nickel were chosen for evaluation in this assessm ent because both can be irritating and sensitizing. Chrom i um and nickel ar e used in the production of stainless steel and other m e tal alloys. Chrom i um , in the hexavalent form , Cr+6 , can dam a ge the nose and cause

cancer. Sim ilarly, workers who have breathed la rge am ounts of nickel have developed lung and nasal sinus cancers. Total chrom i um in urban air typically ranges from 0.01 to 0.03 μg/m 3 (ATSDR, 2000c), and nickel concentrations in urban air range from 0.001 to 0.328 μg/m 3 (ATSDR, 1997b).

To evaluate chrom i um and nickel, the OSHA PELs (chrom ium
, 1 m g /m 3 ; nickel, 1 m g /m 3 ) were used as a screening benchm ark (NIOSH, 2002). For chrom i um , the ATSDR interm ediate inhalation MRL for Cr +6 PM (1.0 μg/m 3 ) was also used (ATSDR, 2000c). For this evaluation, it

was assum e d that chrom i um would be released as solid PM, not as a m i st, in order to com p are

m easurem ents with the ATSDR MRL, which is specific to PM concentrations.

Data for evaluating chrom i um and nickel cam e m o stly from the EPA W T C m onitoring database. A total of 21 air sam p les, collected between Septem ber 23 and January 31 at Building 5, were evaluated for chrom i um and nickel at Ground Zero. None of the sam p les evaluated exceeded a screening benchm ark for either chrom i um or nickel, nor did any values detected by ORD m onitoring on the Ground Zero perim e ter (Figure 18) exceed any benchm ark values for chrom i um or nickel. On the basis of the results reported, chrom i um and nickel releases would not have been expected to cause any adverse health effects within Ground Zero.

Approxim a tely 512 m onitoring sam p les collected at sites surrounding Ground Zero were evaluated f o r chrom i um , including 86 sam p les taken at the Staten Island landf ill and 16 sam p les from personal air m onitors worn by NYC fire departm e nt personnel. Approxim a tely 637

m onitoring sam p les collected at sites surrounding Ground Zero were evaluated for nickel, including 86 sam p les taken at the Staten Island landf ill. Sam p les were collected between Septem ber 23 and January 31. None of the sam p les evaluated for either chrom i um or nickel exceeded a screening benchm ark. On the basis of the sam p les collected, chrom i um and nickel releases would not have been expected to cause any adverse health effects at sites surrounding Ground Zero.

Like m o st contam inants, however, elevations in chrom i um were seen in concentrations

m easured near Ground Zero, and near Septem ber 11 in tim e. At the Ground Zero m onitoring, W T C building 5, chrom i um was not detected in four sam p les from Septem ber 23 to October 8, but then it was detected at 0.24 and 0.38 μg/m 3 on October 11 and October 15. Further sam p ling at Ground Zero through February of 2002 showed m o stly non-detects (9 sam p les) and sam p les near typical background for chrom i um (4 sam p les between 0.02 and 0.07 μg/m 3 ), except for one higher reading at 0.22 μg/m 3 in January, 2002. Chrom i um sam p ling at all other sites around Ground Zero showed the sam e trend: elevati ons above typical urban background through about

m i d-October, with m easurem ents then dropping to typical urban background (with a spike in January, which m a y or m a y not be due to Ground Zero em issions) through the sam p ling in February of 2002.

Unlike chrom i um , nickel was not found elevated above background at any tim e or location

DRAFT--DO NOT QUOTE OR CITE 64 October 2002in sam p ling. Measurem ents were m o stly non-detects in within Ground Zero and in all locations

m easuring nickel, with sporadic m easurem ents all less 0.1 μg/m 3

.

DRAFT--DO NOT QUOTE OR CITE 65 October 2002IV.c. Polychlorinated Biphenyls (PCBs)

PCBs are a group of synthetic organic chem icals potentially com posed of 209 individual chlorinated biphenyl com pounds (known as congene rs). PCBs were m a nufactured as m i xtures of individual com pounds having 1 to 10 chlorine atom s on the m o lecule. Being relatively stable

com pounds, their high boiling points and resistance to breakdown by high tem p eratures m a de them useful in a broad array of industrial app lications. Furtherm ore, as PCBs do not conduct electric current, they were useful for com m e rcial purposes as insulating m a terial and electrical dielectric fluid in transform e rs and capacitors.

In 1971, Monsanto Corporation, the m a jor U.S. producer, voluntarily restricted the sales of PCBs to uses as dielectric fluids in “closed elect rical system s.” This restriction was prom pted by growing evidence of PCBs’ persistence in the environm ent, their tendency to bioaccum u late in anim al tissues, and their toxic effects, nam e ly as probable hum an carcinogens. Monsanto ceased PCB m a nufacture in m i d-1977 and shipped the la st inventory in October 1977 (Erickson, 1997). Regulations issued by EPA beginning in 1977, principally under the Toxic Substances Control Act (40 CFR 761), have strictly lim ited the production, im port, use, and disposal of PCBs.

Because the W T C was built in the early 1970s, it can be surm ised that PCBs m a y have been present or contained in transform e rs, capacitors, electrical insulating and cooling applications, fire-resistant coatings to buildi ng m a terials, and electrical fluorescent lighting fixtures. As a consequence of the collapse of the W T C towers, m a ny of these m a terials were pulverized, ruptured, or burned, which caused PCBs to be released into the surrounding environm ent. Additionally, PCBs were likely entrained within the sm oke plum e that em anated from the debris piles at Ground Zero. The prim ary focus of this section is to evaluate the potential hum an health risks that m a y be associated with inhalation exposure to the variable air concentrations of PCBs m easured in lower Manhattan in the afterm ath of the disaster.

IV.c.1. Air Monitoring for PCBs PCBs were m onitored at 12 different sites around Ground Zero and in other areas of lower Manhattan. Several hundred am bient air sam p les were collected between Septem ber 16, 2001, and April 24, 2002. One-day sam p les were taken using a high-volum e polyurethane foam (PUF) and glass f i ber f ilter (GFF) sam p ler. The GFF is used to collect and retain PCB- contam inated particles that m a y be present in the air, whereas the PUF m a terial is used to capture any gaseous form of PCBs. In this m onitoring program , only the sum of the PCB congeners present in air was quantified. Figure 21 displays the locations of the PCB air m onitoring stations in lower Manhattan.

The prim ary source of PCB m onitoring data used in this analysis was the publicly accessible inform ation posted on EPA’s W T C web site (http://www.epa.gov/wtc). This inform ation is current through April 24, 2002. Table 3 presents a sum m a ry of the am bient air

sam p ling results for PCBs in and near the W T C disaster site.

To put these m easurem ents into perspective, background levels of total PCBs in air at urban locations in the U.S. are typically in the range of 1 to 8 ng/m 3 (ATSDR, 2000a). Slightly elevated air concentrations were found up to 1 m onth after Septem ber 11 only at the Ground

DRAFT--DO NOT QUOTE OR CITE 66 October 2002Zero site, W T C Building 5 SW

. The highest one-day PCB air m easurem ent of 153 ng/m 3 occurred on October 2, 2001. This level is approxim a tely three-fold higher than the next two PCB levels observed at W T C Building 5 on Septem ber 16 and October 4: 55.9 and 58.6 ng/m 3

, respectively. By Novem b er 2, PCB levels at this site had further decreased to 18 ng/m 3

. Measurem ents from Novem b er 6, 2001 to April 24, 2002 showed that total PCB levels in air decreased to below the lim its of detection. Barclay and W e st Broadway registered the next highest one-day PCB air concentration at 77 ng/m 3 on October 4. This m onitor bordered a restricted zone, but could represent a concentration in an area just above the corner of Barclay and W e st Broadway that was unrestricted after Septem ber 19. This October 4 m easurem ent was about nine tim es greater than the m easurem ent taken October 2 at this site (8.3 ng/m 3 ), and approxim a tely ten tim es higher than typical ur ban background air. By Novem b er 2, PCB air levels had decreased to 9.7 ng/m 3

. Following Novem b er 2, total PCB was not detected at Barclay and W e st Broadway until February 19, 2002, at which tim e a concentration of approxim a tely 3 ng PCB/m 3 was detected. From February 24, 2002, through April 24, 2002, PCB levels dropped below the lim it of detection. Because the lim its of detection were within the range of typical urban air m easurem ents, it can be concluded that PCBs had dropped to and

rem a ined within this range of typical urban air concentrations after Novem b er 8.

To summ a rize, elevations above the typical background range of 1 - 8 ng/m 3 were only seen in the initial m onth after 9/11, and only within Ground Zero and the border sam p ling location of Barclay and W e st Broadway. All m onitoring sites to the west of Ground Zero showed no elevation above background PCB concentrations at any tim e in the m onth following the disaster. By Novem b er 8, PCB levels in air were within the range of expected urban background air at all m onitoring locations, including Ground Zero.

IV.c.3. Potential Human Health Consequences of Exposure to PCBs in Air Different approaches are used here to assess potential health effects of exposure to PCBs at or near the W T C site. First, EPA’s procedure for estim ating cancer risk is used. Then,

com p arison of air concentrations to benchm arks published by ATSDR, NIOSH, and OSHA are conducted.

EPA currently classifies PCBs as B2 carcinogens; a probable hum an carcinogen (IRIS, 2002). The basis for this classification stem s largely from long-term anim al studies supplem ented with hum an studies. A 1996 study found liver tum o rs in fem a le rats exposed to Aroclors1260, 1254, 1242, and 1016, and in m a le rats exposed to 1260. These m i xtures contain overlapping groups of congeners that, together, sp an the range of congeners m o st often found in environm ental m i xtures. Earlier studies found high, statistically significant incidences of liver tum o rs in rats ingesting Aroclor 1260 or Clophen A 60 (Kim brough et al., 1975; Norback and W e ltm an, 1985; Schaeffer et al., 1984). Mechanistic studies are beginning to identify several congeners that have dioxin-like activity and m a y prom ote tum o rs by different m odes of action.

PCBs are absorbed through ingestion, inhalation, and derm al exposure, after which they are transported sim ilarly through the circulatory system

. This pattern provides a reasonable basis for expecting sim ilar internal effects from different routes of environm ental exposure. Inform ation on relative absorption rates suggests that differences in toxicity across exposure routes are sm all. The hum an studies are being updated; currently available evidence is

DRAFT--DO NOT QUOTE OR CITE 67 October 2002inadequate, but suggestive of PCB carcinogenicity.

From the dose-response data derived from anim al studies, the EPA has calculated an upper bound cancer slope factor of 1*10 -4 [μg/m 3 ] -1 associated with continuous lifetim e inhalation exposure to PCBs. This slope factor pertains to exposure to total PCBs, which m a y or m a y not contain dioxin-like PCBs. For exposure to di oxin-like PCB congeners alone, the slope factor developed for dioxin-like com pounds should be applied (EPA, 2000a). This assessm ent does not consider exposure and risk from dioxin-like PCBs because these congeners were not m easured separately. The Toxic Equivalent (TEQ) concentrations discussed in the dioxin section below are specific to dioxin and furan congeners only.

A cancer risk from a less-than-lifetim e inhalation exposure to total PCBs is given as:

Risk = LAC * UR (2)

where LAC is the air concentration averaged over a lifetim e, calculated as: AC * [ED/LT], where AC is the average air concentration during the period of exposure (μg/m 3 ), ED is the exposure duration (days), LT is lifetim e (days), typically 70 years, and UR is the unit risk factor, expressed in units of 1/concentration.

In order to conduct a sim p le screening exercise to evaluate the cancer risk from inhalation of elevated levels of PCBs near the W T C site, a representative air concentration and a tim e during which exposure to that concentration occurred need to be determ ined. The areas in which PCB air concentrations were elevated were generally located within the “restricted zone”. Still, even if an individual were exposed to th e highest concentration found at 153 ng PCB/m 3 for a period of 1 m onth (and all the data suggests that elevations did not exist beyond 1 m onth), the lifetim e cancer risk would be estim ated at about 2*10 -8 (calculated as: [0.153 μg/m 3 ] * [30 days/ (70 years*365 d/yr)] * [1*10 -4 (μg/m 3 ) -1 ] ). EPA regulatory program s, such as the Superfund Program , typically consider individual increm ental cancer risk estim ates m a de in this m a nner (i.e., in the context of a scenario-based risk assessm ent) in the range of 10 -4 to 10 -6 to be of potential significance, depending on the circum stances. On this basis, an increm ental cancer risk estim ate in the range of 10 -8 is judged to be insignificant.

ATSDR has published a Toxicological Profile for PCBs (ATSDR, 2000a). This Toxicological Profile is a com p rehensive revi ew and summ a ry of existing health effects inform ation relevant to hum an exposures. From this review, it is concluded that all the m easured PCB levels in air in or around the W T C site were well below the levels of significant exposure to PCB m i xtures that were found not to cause adverse effects in experim e ntal anim als as a consequence of short-term inhalation exposure. These no-observed-adverse-effect-levels (NOAELs) in experim e ntal anim als ranged from 1.5 x 10 6 ng/m 3 for renal effects to 9 x10 3 ng/m 3 for hepatic effects. These NOAELs are one to six orders of m a gnitude higher than the highest PCB air levels m easured in Lower Manhattan.

Occupational exposure lim its provide an additional perspective by which to evaluate potential non-cancer health effects that m a y be associated with inhalation exposure to PCBs

m easured in the air at or near the W T C site. NIOSH publishes RELs and OSHA publishes PELs

DRAFT--DO NOT QUOTE OR CITE 68 October 2002for occupational exposures to chem ical contam inants. The NIOSH REL is 1 x 10 3 ng/m 3 as an 8- hr TW A air concentration (NIOSH, 2002). The REL is associated with long-term or repeated exposures and is protective of effects on the liver and the reproductive system

. All PCB air

m easurem ents at or near the W T C site have been below the NIOSH REL. The OSHA PEL is 5 x 10 5 ng/m 3 as an 8-hr TW A air concentration (NIOSH, 2002). The PEL is associated with longterm or repeated exposures and is protective of effects on the skin (derm a titis). All PCB air

m easurem ents at or near the W T C site have been below the OSHA PEL.

DRAFT--DO NOT QUOTE OR CITE 69 October 2002Table 3. Summ a ry of PCB m onitoring data between Septem ber, 2001, and April, 2002.

Location Sam p ling Date Concentration ng PCB/m 3 air Sam p ling Date Concentration ng PCB/m 3 air
Albany & Greenwich 9/16 - 10/4; 7 sam p les N D 11/02-12/11; 10 sam p les N D

10/8 9 .2 12/19/01 2.2
10/11 - 10/26; 4 sam p les N D 12/27 - 4/24; 29 sam p les ND

10/30/01 1.8
Albany & South End 9/16 - 4/24/; 53 sam p les N D

Barclay & W e st Broadway 9/16/01 & 9/23/01 ND 10/15 - 10/30; 4 sam p les N D

9/27 38.7 11/02

10/2 8 .3 11/8 - 2/14; 23 sam p les N D

10/4 77.0 2 /19 3 .2

10/8 N D 2 /21 - 4/24; 15 sam p les N D

10/11 25.0
Church & Dey 9 /16 7 .0 10/8 4 .5

9/23 4.0 10/11 2.2

9/27 5.0 10/15 - 10/26; 3 sam p les ND

10/2 17.9 11/02 3.3

10/4 13.3 11/8 - 4/24; 39 sam p les N D
Church & Vesey 11/15 - 11/27; 4 sam p les N D 12/11 1.4

12/4 1 .7 12/19 - 4/24; 30 sam p les N D

12/6 N D

EPA TAGA Lab 9 /11 - 4/24; 54 sam p les N D
Liberty & Trinity 9/16 8.1 9 /23 - 4/24; 52 sam p les N D
Liberty & Broadway 9/23 - 9/28; 3 sam p les N D 10/8 1 6

10/2 8 .2 10/11 - 10/26; 4 sam p les N D

10/4 N D

Rector & South End 9/16 - 4/11; 51 sam p les N D

DRAFT--DO NOT QUOTE OR CITE 70 October 2002Table 3. Sum m a ry of PCB m onitoring data between Septem ber, 2001, and April, 2002 (cont’d).

Location Sam p ling Date Concentration ng PCB/m 3 air Sam p ling Date Concentration ng PCB/m 3 air
Vesey & W e st 9/16 & 9/27 ND
Liberty & South End 9/23 - 5/28; 67 sam p les N D

W T C Building 5 SW 9/16 55.9 10/15 16.0

10/2 153.0 10/18 5.7

10/4 58.6 10/26 6.8

10/8 18.1 11/2 18.2

10/11 28.2 11/6 - 4/24; 38 sam p les N D

DRAFT--DO NOT QUOTE OR CITE 71 October 2002

### 7 10

9

8 6 5 12 4 3 2 11

1 KE Y

( 1 ) EPA Ta ga La b

( 2 ) B a rclay & W e st B r oadw a y
(3 ) C h u r ch &V e se y
(4 ) C h u r ch &D e y
(5 ) L i be r t y &T r in ity
( 6 ) L i bert y & B r oa dway

( 7 ) Li bert y & G reenwi c h

(8 ) R e c t o r &S o uth E n d

(9) A l ban y & So uth E n d

( 1 0) Li b ert y & Sou t h En d

(1 1 ) V e se y &W e st

(11 ) W T C B u ilding 5 SW

Figure 21. Location of PCB m onitoring stations.

DRAFT--DO NOT QUOTE OR CITE 72 October 2002IV.d. Dioxin

Dioxin-like com pounds (referred to also in discussions below sim p ly as “dioxins”) are form ed during com bustion, and it is expected that production of these com pounds would have resulted from the initial im pact and ensuing fires at the W T C. Dioxin-like com pounds m a y be form ed in other ways as well, such as in the chlorine bleaching process for paper products or in the m a nufacturing process for certain chlorinated organic chem icals. However, uncontrolled or im properly controlled com bustion appears to be the m a jor source of new em issions (EPA, 2000). A total of 30 com pounds are considered to be “d ioxin-like”: 7 polychlorinated dibenzo-p-dioxins (abbreviated dioxins), 10 polychlorinated dibenzof urans (furans), and 13 coplanar PCBs. These individual com pounds are called “congeners.” Measurem ents at the W T C included only the 17 polychlorinated dioxin and furan congeners, not th e PCB congeners (total PCBs were m easured, as discussed above). Because dioxin-like com pounds are present at m i nute quantities, concentrations in this section will be described in term s of picogram s per cubic m e ter (pg/m 3 ).

Concentrations of dioxin-like congeners are e xpressed on a toxic equivalent, or TEQ basis. A TEQ concentration is calculated as the sum of the toxically equivalent concentrations of each of the 17 congeners. A congener’s TEQ concentration is calculated as its concentration (C i ) tim es its toxicity equivalency factor, or TEF i . TEF values are equal to 1.0 or less, and relate the toxicity of 16 of the 17 congeners to the m o st toxic congener, 2,3,7,8-TCDD (the 17 thcongener naturally assigned a TEF of 1.0). An overall TEQ concentration is, therefore, E (TEF i *C i ). W h en a congener was not detected in the sam p le, a value of one-half the detection lim it was used for that congener in calculating the TEQ concentration. This is the traditional approach to calculating a TEQ concentration when som e of the congeners are not detected and others are; alternate approaches include assigning either 0 or the detection lim it to the congeners that are not detected.

The TEQ concentrations on the W T C web site we re developed using the “International” set of TEF values (I-TEF; EPA, 1989). In 1998, the W o rld Health Organization proposed a new set of TEF values (W HO-TEF; Van den Berg, 1998). The principal change relevant to quantifying the TEQ concentration of a m i xture com p rised of the 17 dioxin and furan congeners is that the TEF for the penta dioxin-like congener, 1,2,3,7,8-PCDD, has been increased from 0.5 to 1.0. The other change of less im pact to calculating the TEQ concentration is that the TEF values of the two octa congeners, OCDD and OCDF, were reduced from 0.001 to 0.0001. Since the penta congener occurs in m o st sam p les, the net effect of this change is to increase the TEQ concentration slightly, in the range of 5-10%, depending on the prevalence of 1,2,3,7,8-PCDD in the sam p le. For exam ple, on the sam p le taken from the W T C Building 5 m onitor on Septem ber 23, when the I-TEQ concentration was 161 pg TEQ/m 3 , the 1,2,3,7,8-PCDD concentration was 40.8 pg/m 3

. In the I-TEF schem e , this contributes 20.4 pg/m 3 , but in the W HO-TEF schem e , this would add 40.8 pg/m 3 to the final TEQ concentration. Therefore, the m easurem ent of 161 pg TEQ/m 3 would increase to 181 pg TEQ/m 3 when switching to the W HO-TEF schem e , an increase of about 12%. An exam ination of the data shows that other I-TEQ concentrations would also increase, som e by less than 5%.

This assessm ent uses the I-TEQ concentrations presented on the EPA W T C web site. Converting to W HO-TEQ concentrations would m a ke a sm all and insignificant change to the

DRAFT--DO NOT QUOTE OR CITE 73 October 2002calculations presented in this section, would not result in changing any of the principal findings, and would possibly be confusing to those who noti ce a difference in the concentrations described here com p ared to those posted on the EPA web site.

Som e of the m a jor health risks associated with dioxin exposure include, but are not lim ited to, cancer and noncancer effects, including reproductive, developm ental, and imm unologic effects. A com p lete discussion of the health effects of exposure to dioxin-like com pounds can be found in EPA’s draft Dioxin Reassessm ent Docum e nt (EPA, 2000). This W T C report draws on procedures outlined in that docum ent for conducting sim p le screening assessm ents relating to potential long-term cancer and noncancer effects from exposure to dioxin concentrations

m easured on and near the W T C site.

IV.d.1. Dioxin Air Monitoring Data Figure 22 shows the location of 16 air m onitoring sites at which dioxin m easurem ents have been taken. Four of the sites had very few sam p les, so the focus in this section is on the 12

sam p lers that had a significant num ber of sam p les. At all sites, high-volum e air sam p lers were used. Each sam p ler contained both a GFF and a PUF cartridge. The GFF is used to collect and retain particle-phase dioxins, whereas the PUF m a terial is used to capture gas-phase dioxins. The GFFs and PUFs were sent to laboratories for m easurem ent of the 17 dioxin-like congeners using EPA m e thod SW 8290.

Two different groups conducted the dioxin m on itoring. Nine of the 12 sites m easuring a significant num ber of dioxin sam p les were “lettered” sites m a naged by the EPA’s Environm ental Response Team (EPA ERT). These 9 sites sam p led for 8 hours per sam p ling event. On the other hand, 3 of the 12 sites were “num bered” sites were established by the New York State Departm e nt of Environm ental Conservation ( NYSDEC), and they m onitored for 72 hours per

sam p ling event. For dioxin sam p ling, these 3 NYSDEC sam p lers were m a naged by EPA’s Region 2 personnel, who sent the sam p les to EPA’s Region 7 laboratory for analysis. For this reason, these will be referred to as the Region 2/7 m onitors/sam ples.

The am ount of tim e the m onitor operates directly affects the am ount of air that went through the m onitors for dioxin collection: the Region 2/7 sam p ling captured dioxins contained in about 1000 m 3 of air (i.e., about this m u ch air was drawn into the sam p ler over 72 hours), whereas the EPA ERT sam p ling captured dioxins in about 7 m 3 air. The m a jority of the EPA ERT sam p les sim p ly did not contain enough m a ss of dioxins to be able to detect, m u ch less quantify, the dioxin-like congeners in the sam p le. Wh en the m e thod cannot detect the congener in the sam p le, a result of “nondetect” (ND) is reported, and the detection lim it (DL) is supplied. The m e thod’s detection lim it is calculated by dividing the lowest am ount of dioxin that it can detect (on the GFF and PUF) by the air that c ontained that am ount, nam e ly the air that flowed through the sam p ler. The greater the air flow, the greater the divisor for the unchanging detection am ount, and the lower the detection lim it. Except for the high concentrations

m easured within and near Ground Zero from Septem ber through late Novem b er, m o st of the

sam p les taken by the EPA ERT sam p lers contained m o stly non-detects. Therefore, TEQ concentrations ended up being calculated with all or m o st congeners set equal to a value of onehalf the detection lim it.

DRAFT--DO NOT QUOTE OR CITE 74 October 2002Calculating TEQ concentrations with m o st c ongeners assigned values of one-half detection lim it is not an issue when a suf f i cient quantity of air is drawn into the m onitor, and the inability to m easure the dioxin in the sam p le truly does signify a very low am ount of dioxin in the sam p le. For exam ple, congeners in the Region 2/7 sam p les could be quantified if they were present at concentrations higher than about 0.5 pg/m 3 because enough air was drawn into the m onitors leaving behind enough dioxin m o lecules on the m onitor’s filters. The congeners in the EPA ERT sam p les could not be quantified unless they were present at about 5-10 pg/m 3

. Wh en m o st of the congeners reported a non-detect in one of the Region 2/7 sam p les, the calculated TEQ concentration was in the range of 0.01 to 0.10 pg TEQ/m 3 , whereas when m o st of the congeners were reported as non-detect in the EPA ERT sam p les, the calculated concentration ranged from 0.5 to 5.0 pg TEQ/m 3

. As will be discussed below, typical urban air concentrations are in the range of 0.10 to 0.20 pg TEQ/m 3 , and these m easurem ents com e out of studies where, like the Region 2/7 sam p les, a suf f i ciently large quantity of air was drawn into the m onitors.

Assigning one-half detection lim it for non-detects is typical and appropriate for evaluating exposure to airborne contam inants, dioxins or otherwise. In som e circum stances, this practice can underestim ate the am ount of contam inant in the air - i.e., when the actual concentration is just below the detection lim it and above the half-detection lim it value. However, in this case, it is clear based on com p arison with the Region 2/7 sam p les and from other historical

m easurem ents around the United States, that the practice of assigning one-half detection lim it to non-detects in the EPA ERT sam p les resulted in an overestim ate of the TEQ concentration when

m o st of the congeners in the sam p le were non-detects.

For purposes of analysis in this section, a lim ited set of the dioxin data is used. Table 4 shows reported TEQ concentrations for the W T C Building 5 EPA ERT m onitor, the Church & Dey EPA ERT m onitor, and the Park Row Region 2/7 m onitor. These values were calculated at ND = 1⁄2 DL; in parenthesis for the two EPA ERT m onitors is the TEQ calculated at ND = 0. The W T C Building 5 m onitor had the highest concentrations, and the Church & Dey m onitor was in the predom inant downwind direction for m o st m onitoring events and had the second highest m easurem ents. The Park Row m onitor began operation on October 12 and had

num erous m easurem ents through March of 2002. Figure 22 shows the location of these three

m onitors. The following observations are based on the data in Table 4:

• T he W T C and Church & Dey m easurem ents from the first m easurem ent day of Septem ber 23 through Novem b er 21 show unam b iguous elevation, with concentrations ranging from about 10 to 170 pg TEQ/m 3

.

• I n this sam e tim e fram e and for these two sam p lers, the influence of having high detection lim its is seen in a few sam p les (W TC sam p le on 10/4: 176 pg TEQ/m 3 at ND = 1⁄2 DL versus 140 pg TEQ/m 3 at ND = 0; W T C sam p le on 10/11: 52.4 versus 9.6), but m o stly, the congeners were detected and quantified, and TEQs were sim ilar at ND = 0 and ND = 1⁄2 DL.

• T he 6 Park Row m easurem ents between October 12 and October 29 averaged 5.6 pg TEQ/m 3

. These m easurem ents are consistent with the m i d- to late-October

m easurem ents at Church & Dey, which is slightly off-site from Ground Zero, of

DRAFT--DO NOT QUOTE OR CITE 75 October 200210 to 20 pg TEQ/m 3

. Further, the Church & Dey m easurem ents of 10 - 20 pg TEQ/m 3 for m i d to late October are consistent with the W T C m easurem ents for that tim e period of 20 - 50 pg TEQ/m 3

. In other words, the highest m easurem ents are onsite (W TC); the next highest m easurem ents are slightly offsite (Church & Dey), and slightly lower concentrations are farther offsite (Park Row). This is strong evidence that em issions from the W T C site are the cause for elevated air concentrations within and near the W T C site.

• T he Park Row m easurem ents from Decem ber 2001 through the last reported

m easurem ents of March 18, 2002, are less than 0.11 pg TEQ/m 3 , and all the 2002

m easurem ents are less than or equal to 0.05 pg TEQ/m 3

. These values are consistent with those of the other two Region 2/7 sam p lers (see Figure 22). They are also consistent with typical urban concentrations of dioxin TEQs (see discussion after bullets), which leads one to believe that these concentrations

m i ght be representative of typical “background” New York conditions.

• T he Decem ber through April m easurem ents from the W T C Building 5 and Church & Dey m onitors are nearly all non-detects. The reported concentrations average about 1.4 pg TEQ/m 3 , but this is of lim ited interpretive value since the detection lim its were too high. The actual concentrations could be m o re like the concentrations of about 0.05 pg TEQ/m 3 found at the Park Row sam p ler, but it is not possible to conclude that since the data are not available.

Other m easurem ents m a de in the United States and around the world can be used to put these m easurem ents in perspective. As noted earlier, EPA’s draft Dioxin Reassessm ent

com p iled urban and rural air m onitoring studies and found average am bient concentrations of 0.12 pg TEQ/m 3 for urban and 0.017 pg TEQ/m 3 for rural settings. Higher concentrations have been identified in the literature, particularly near a known source of dioxin em issions. The highest TEQ concentration reported in the U.S. was > 1.0 pg/m 3 , downwind of an incinerator in Niagara Falls, NY. Concentrations in the plum e of a solid waste incinerator in Colum bus, OH, that was known to be em itting large am ounts of dioxins were about 0.25 pg TEQ/m 3

. In this case, the stack was very tall (about 80 m e ters) and air m easurem ents were taken about 2 kilom e ters away. Background air concentrations in Colum bus were m easured to be about 0.05 pg TEQ/m 3

. Air concentrations near an incinerator in Japan adjacent to a U.S. Naval Air Base were regularly m easured on the base for dioxin-like com pounds. Measurem ents at the nearest downwind m onitor, at about 200 m e ters, averaged 3.5 pg TEQ/m 3 for weekly sam p les over a 15-

m onth period. For five sam p lers (including the nearest downwind sam p ler) at various locations on the base up to 800 m e ters, the average air concentration was 1.6 pg TEQ/m 3

. An exam ination of the air concentration data on this base in conjunction with wind rose data, suggested that a background air concentration in this area was less than 0.5 pg TEQ/m 3 and that m easurem ents above that were due to the influence of the incinerator (W alker, et al., 2002). Other

m easurem ents in cities in Japan have been in the 0.3 to 0.7 pg TEQ/m 3 range, and these are the highest that have been reported as typical air concentrations worldwide.

DRAFT--DO NOT QUOTE OR CITE 76 October 2002Although none of these literature m easurem ents can be assum e d to represent New York levels, they provide som e basis f o r perspective. Certainly, no reports in the literature could be found on sim ilar circum stance where there is, what is essentially, an area source at ground level continually em itting dioxins near to where indivi duals are exposed. It would be reasonable to conclude that the concentrations to which individuals could potentially be exposed, in the range 10.0 to 170.0 pg TEQ/m 3 within and near the W T C site found through the latter part of Novem b er, are likely the highest am bient concentrations that have ever been reported.

IV.d.2. Potential Human Health Consequences of Exposure to Dioxins in Air The exposure of hum ans to dioxins is predom inantly through the food supply; about 95% of exposure is through consum ption of anim al food products. Inhalation exposure and absorption via the skin are generally m i nor pathways for the average U.S. citizen (i.e., the background population). EPA has estim ated that about 4% of the background hum an dose of dioxin is due to inhalation, based on an average urban level of 0.12 pg TEQ/m 3 and an inhalation rate of 13.3 m 3 /day. If the concentration of dioxin in the air is increased, the am ount of exposure due to inhalation would be increased, but the total am ount of dioxins contributed by the inhalation pathway m i ght still be sm all in com p arison to the contribution m a de by f ood ingestion.

In the W T C situation, elevated dioxin concentrations in the air can be expected to increase the proportion and extent of hum an exposure via i nhalation and possibly skin contact routes for those people residing or working close to the W T C location. The extent to which these elevated atm o spheric levels will translate into increased hum an doses depends on an individual’s pattern of exposure, considering, for exam ple, his or her location in relation to the W T C and downwind areas; the duration and tim e period of exposure such as workshift and return to residence patterns, m ovem e nt and activity patterns during the tim e of elevated atm o spheric levels; and whether respiratory protection devices were used. Dioxin-like com pounds exist substantially in the atm o sphere attached to particles, and these devices would rem ove a substantial portion of the dioxins through the rem oval of particulates; if these respirators contained a carbon filter, a substantial portion of the dioxins in vapor phase would also be rem oved.

This section will use the data shown in Table 4 to conduct cancer and non-cancer

assessm ents of an individual’s inhalation expos ure to dioxins. The procedures used are described in detail in the draft Dioxin Reassessm ent (EPA, 2000; available at, http://www.epa.gov/ncea/dioxin.htm ) , with further references supplied below as necessary.

1. Daily Inhalation Doses Cancer and non-cancer assessm ents entail the developm ent of a “dose” term , which in this case is the dose received via inhalation. Inhalation dose estim ates require assum p tions about the hourly rate of inhalation (m 3 /hr), the num ber of hours per day a person inhales at the site where he or she could be exposed (which could obviously be less than 24 hours if the individual does not live in the vicinity where air concentrations m easurem ents were taken), the tim e period during which this exposure occurs, and, of course, the air concentration to which the individual is exposed.

Daily inhalation exposure dose is given by:

DRAFT--DO NOT QUOTE OR CITE 77 October 2002DD = [IN * HRD * C * ABS]/[BW ] (3)

where DD is daily dose (pg TEQ/kg-day); IN is the inhalation rate (m 3 /hr), HRD is the hours/day of inhalation, C is the concentration (pg TEQ/m 3 ), ABS is the fraction of contam inant inhaled which is absorbed (unitless), and BW is the body weight (kg). The draft Dioxin Reassessm ent

assum e s an adult body weight of 70 kg and an absorption fraction of 0.8 for TEQ exposures, both from inhalation and food consum ption, and these assum p tions are used here. The average daily dose (ADD) is calculated sim p ly as the average of the daily doses over the period of exposure.

2. Exposure Scenarios The scenarios which were evaluated here include:

1) W T C worker: This individual was exposed 10 hours per day, 5 days per week, in the tim e period between Septem ber 12 and Novem b er 30, 2001. This tim e fram e roughly corresponds to the tim e when it seem ed clear that dioxin air levels were elevated according to the m onitoring data. Measurem ents from the W T C Building 5 m onitor represent the concentration to which this individual is exposed. A tim e-weighted average (TW A ) air concentration was derived for this period. The air concentration between Septem ber 12 and Septem ber 23 (the date of the first

m easurem ent at the W T C m onitor) is assum e d to be equal to the Septem ber 23 m easurem ent, and the concentration between Novem b er 8 (the last date in Novem b er for the W T C m onitor) and Novem b er 30 was sim ilarly assum e d to be equal to the m easurem ent on Novem b er 8. These seem to be reasonable assum p tions since the Septem ber 23 m easurem ent from the W T C

m onitor was the second highest found at 161 pg TEQ/m 3 , and the Novem b er 8 m easurem ent of 5 pg TEQ/m 3 reasonably reflects the downward trend of m easurem ents at the site. Between Septem ber 12 and Novem b er 30, a TW A air concentration was derived to represent the concentration to which the workers were exposed. A TW A concentration is not the sam e as the sim p le average of concentrations m easured. To derive the tim e-weighted concentration, concentrations were assigned to each day between Septem ber 12 and Novem b er 30. From one

m easurem ent to the next, air concentrations were assum e d to linearly rise or fall. For exam ple, if the concentration was m easured as 100 pg TEQ/m 3 on one day and 5 days later it was 50 pg TEQ/m 3 , the concentrations assigned to the intervening days were 90, 80, 70, and 60 pg TEQ/m 3

. The TW A concentration is then sim p ly the average of all the concentrations assigned to days when the worker was assum e d to be exposed. W ith these assum p tions, the average TEQ concentration during this tim e was calculated as 60.7 pg/m 3

. The rate of inhalation for a W T C worker was 1.3 m 3 /hr. This is equivalent to the rate for a “laborer” as quantified in EPA’s Exposure Factors Handbook (EPA, 1997).

2) Office worker: This individual is exposed 10 hours per day, 5 days per week, and the exposure began on Septem ber 19, corresponding to the tim e when individuals were allowed back into office buildings outside of the Ground Zero site itself but in areas initially “restricted” near Ground Zero. The office worker was assum e d to be exposed to air concentrations m easured by the Park Row m onitor. This sim p listically assum e s that the air concentrations within of f i ce buildings near Ground Zero were sim ilar to air concentrations outside of office buildings this close to Ground Zero. The period of exposure was Septem ber 19 to Novem b er 30, and the sam e strategy to derive TW A concentrations was used as for the W T C worker. The TEQ air

DRAFT--DO NOT QUOTE OR CITE 78 October 2002concentration from Septem ber 19 to October 12 was assum e d to be 8.4 pg/m 3 , the m easurem ent on October 12 at the Park Row m onitor, and the TW A concentration between Septem ber 19 and Novem b er 30 was 4.8 pg TEQ/m 3

. The rate of inhalation for an office worker was assum e d to be the average inhalation rate of 1.0 m 3 /hr, which is defined as “light activity” in EPA’s Exposure Factors Handbook (EPA, 1997).

3) Resident: This individual was exposed 24 hours per day, 7 days per week, and the exposure began on Septem ber 19 and ended on Novem b er 30. As with the office worker scenario, the

assum p tion here again was that individuals livi ng near Ground Zero, in the vicinity of the Park Row m onitor, were m o re exposed after Septem ber 19, when som e of the locations outside of Ground Zero opened up to workers and residents. The daily inhalation rate was 0.55 m 3 /hr, an average daily rate, activity unspecified, as developed in EPA’s Exposure Factors Handbook (EPA, 1997). As noted, the air m onitor used to characterize the air concentration was the Park Row m onitor, which was located in an area not restricted after Septem ber 19. The average TEQ concentration during this tim e was 4.8 pg/m 3 , as noted above.

3. Procedure for Cancer Risk Estimation These assum p tions and the resulting ADDs are shown in Table 5. Cancer risk were estim ated sim p ly as:

LADD = ADD * [ED/LT] (4a)

Risk = LADD * SF (4b)

where LADD is the lifetim e daily dose (pg TEQ/kg-day), Risk is the upper bound increm ental excess lifetim e cancer risk that results from the exposure described by LADD, ADD is the average daily dose during the period of exposure (pg TEQ/kg-day), ED is the exposure duration (days), and LT is lifetim e (days), typically 70 years, and SF is the upper bound cancer slope factor, expressed in inverse units to LADD, or [pg TEQ/kg-day] -1

. The SF of .000156 [pg/kgday] -1 was developed by EPA in 1984 for 2,3,7,8-TCDD exposures (EPA, 1984). It is applied to TEQ exposures in this cancer risk screening exercise. The draft Dioxin Reassessm ent (EPA, 2000) proposed an SF of 0.001 [pg/kg-day] -1 , which applies to dioxin TEQ exposures.

4. Procedure for Non-Cancer Risk Estimation For noncancer risk, a different approach was taken. The best indicator of exposure for persistent, bioaccum u lative, toxic substances such as dioxin is the concentration of the chem ical in the organ or tissue of concern. A com m on m e tric for dioxin exposure is the “body burden”, which is defined as the concentration of dioxins in the body, typically on a whole-weight basis. Body burden in this screening assessm ent is expressed on a lipid basis. It is assum e d that adultsare 25% lipid by weight, so that a lipid-based concentration can easily be converted to a wholeweight-based concentration by m u ltiplying by 0.25.

Dioxins build up and decline over prolonged periods of tim e, since the overall biological half-life (the tim e for half the chem ical to dissipate by either biological degradation or elim ination) of dioxins in the hum an body is approxim a tely 7 years. The use of the body burden as the m easure of dose has im plications for short-term exposures, such as those near the W T C

DRAFT--DO NOT QUOTE OR CITE 79 October 2002site, where elevated exposure rates lim ited to a period of days or m onths contributed to a pool of dioxin already accum u lated in the hum an body over a lifetim e. The current estim ated body burden of dioxin (including only the 17 dioxin and furan congeners, not the dioxin-like PCB congeners discussed above) in U.S. adults is approxim a tely 18 pg TEQ per gram of body lipid (18 ppt TEQ lipid). This average was derived from data on older as well as younger adults. Because exposures were known to be higher in the past, the body burdens of younger adults will be lower than those of older adults. Another f actor contributing to the variability seen in the entire population is dietary pattern; individuals whose diets are higher in anim al fat will have higher body burdens.

The effects of dioxin in hum ans range from biochem i cal changes at or near background levels to potentially adverse effects of increasing severity as body burdens increase above background levels. The “m argin of exposure”, MOE, can be defined as the ratio of body burden where effects are found divided by a body burden at a level of interest. The MOE for dioxin at current average body burdens (i.e., current average body burdens being the level of interest) is considerably less than that typically seen for environm ental contam inants of toxicological

concern. The potential contribution to health risks from specific dioxin sources or specific exposures, such as exposures from inhalation of air with elevated levels of dioxin, is best evaluated through calculating the increm ental contribution of this source to the body burden.

The draft Dioxin Reassessm ent has assum e d that a one-com partm e nt, first-order pharm acokinetic (PK) m odel can be used to estim ate the body burden that results from a specific intake regim e

. This sim p le PK m odel and its application to dioxin TEQs is also described in Lorber (2002). For an exposure of a finite tim e, the nonsteady-state form of this m odel to predict an increm ent in body burden (IBB) from a constant intake dose is given by:

IBB = [ADD/(k * LW )] * [1 - e -kt ] ( 5 )

where IBB is the increm ent of body burden on a lipid basis (pg/g, or ppt, lipid basis); ADD is the average daily dose (pg TEQ/day; not on a body weight basis), k is the first-order dissipation rate constant (1/day), LW is the weight of body lipids (g; equal to full body weight tim es 0.25, as described above), and t is the tim e of exposure (days). Use of Equation (5) with an average ADD over the period of exposure will provide an estim ate of body burden at the end of the exposure. This is the tim e when the increm ental body burden will be at its largest. In the scenarios of this assessm ent, different daily expos ures result from different air concentrations as well as differences in exposure - 5-day work week followed by 2 days of non-exposure for the office worker scenario. Equation (5) is applied on a daily tim e step using Excel® spreadsheet procedures for this sim p le screening exercise.

A value of 17,500 g for the lipid weight (calculated as: 70 kg * 0.25 lipid fraction * 1000 g/kg), and a k of 0.000267 day -1 ( = 0.098 yr -1 , corresponding to a 7.1 year half-life) will be used (Lorber, 2002). Results for this exercise include both an increm ental body burden estim ate, the IBB of Equation (5), calculated at the end of the exposure period, as well as a percent increase over background this represents. This percent increase is calculated as, [IBB/BK] * 100%. The BK is the background, which was assigned a value of 18 ppt TEQ lipid, as described above.

DRAFT--DO NOT QUOTE OR CITE 80 October 20025. Results and Discussion The exposure assum p tions, the cancer risk estim ates, and the increm ental body burdens, are shown in Table 5. Before comm e nting on these results, it is im portant that they be put into perspective for general U.S. population dioxin TEQ exposures. As noted above, the background body burden of dioxin TEQs in adults is 18 ppt lipid. The draft Dioxin Reassessm ent estim ates that the general adult population background TEQ exposure is 65 pg/day, or, expressed on a body-weight basis, 0.93 pg TEQ/kg-day. If this exposure is experienced over a lifetim e, then the resulting increm ental cancer risk from background TEQ exposure to the general adult population is equal to about 1.4*10 -4 (assum i ng the 1984 SF of 0.000156 [pg/kg-day] -1 ).

Table 5 shows that the TEQ ADD due only to inhalation during the period of exposure is 9 pg/kg-day for the W T C worker, 0.55 pg/kg-day for the office worker, and 0.73 pg/kg-day for the nearby resident. Although the W T C worker’s daily exposure is higher than that of the general U.S. population, it is experienced for only a sm all num ber of days. Therefore, when averaged over a lifetim e, the W T C worker dose calculates to an increm ental cancer risk that is 3*10 -6

, which is about 2 orders of m a gnitude lower (100 tim es lower) than the U.S. background cancer risk from dioxin-like com pounds (1.4*10 -4 as calculated above) . The office worker and resident experience increm ental lifetim e cancer risk at about 3*10 -7 , three orders of m a gnitude lower (1000 tim es lower) than background. EPA regulatory program s, such as the Superfund Program
, typically consider individual increm ental cancer risk estim ates m a de in this m a nner (i.e., in the context of a scenario-based risk assessm ent) in the range of 10 -4 to 10 -6 to be of potential significance, depending on the circum stances. Exposure to dioxin-like com pounds represents a unique circum stance, in that background exposures are already within this range and, in fact, at the upper end of this range. Therefore, although the upper bound increm ental cancer risk to the W T C worker is estim ated to be within the range of 10 -4 to 10 -6 , EPA judges these increm ental cancer risks to be of m i nim a l concern because they are 100 tim es and m o re lower than typical background exposures to dioxin-like com pounds.

For noncancer risk, an increm ent of body burden, IBB, approach has been used. Table 5 shows that the exposure of the W T C worker suggests that his or her body burden could rise up to 10% above current average background, but that the nearby office worker and the residents have a rise of only 1% or less. EPA judges these increm ental body burden increases to be of low significance, given the relatively high background exposures already experienced by the general population.

A key uncertainty rem a ins as to the inhalation exposures that could be experienced by W T C rescue or clean-up workers, or nearby resi dent and office workers, who were in the area during the tim e period from about Decem ber onward. As discussed earlier, m o st of the sam p les had non-detects, but after assum i ng that the concentrations in the air were one-half the detection lim it, all the m easurem ents in 2002 from the EPA ERT sam p lers, which included the W T C Building 5 m onitor, the Church & Dey m onitor and m a ny others, ranged from about 0.5 to 5.0 pg TEQ/m 3 , which is about 5 to 50 tim es higher than norm a l background air concentrations. The three Region 2/7 sam p lers, the Park Row, Cham bers St, and the Albany & W e st sam p lers, reported concentrations near 0.05 pg TEQ/m 3 from around Decem ber, 2001, through their last reported m easurem ents in March, 2002. These were further away or generally upwind from the W T C site, so it cannot be assum e d that they represent concentrations to which W T C workers and

DRAFT--DO NOT QUOTE OR CITE 81 October 2002others were exposed. Because the health risk from dioxin exposure is associated with

accum u lation of residues in body tissues, continued exposure throughout 2002 to dioxin, which was possibly elevated in the air, could not be evaluated. The risk screening exercises conducted for dioxin were lim ited to the tim e period when the concentrations were highest and dioxin was detected.

DRAFT--DO NOT QUOTE OR CITE 82 October 2002Table 4. Measured dioxin TEQ air concentrations at the W T C Building 5 m onitor, the Church & Dey m onitor, and the Park Row m onitor (all units = pg TEQ/m 3 ; NR = not reported; all TEQ calculated at ND = 1⁄2 DL except values in parenthesis, which are calculated at ND = 0).

Date WTC - Building 5 D ate C hurch & Dey D ate P ark Row

9/23 161.0 (161.0) 9/23 139.0 (139.0) 10/12 a 8.35

9/27 NR 9/27 50.0 (NR) 10/14 a 0.34

10/2 175.0 (170.0) 10/2 59.3 (57.2) 10/15 a 4.78

10/4 176.0 (140.0) 10/4 51.9 (50.6) 10/16 a 7.55

10/8 32.0 (28.7) 10/8 17.7 (15.5) 10/26 6.51

10/11 52.4 (9.6) 10/11 15.6 (11.8) 10/29 6.34

10/18 NR 10/18 9.6 (8.8) 11/1 3 .05

10/26 28.1 (24.9) 10/26 11.4 (10.2) 11/5 1 .54

11/2 26.8 (25.4) 11/2 16.1 (15.1) 11/8 0 .27

11/6 0 .3 (0) 11/6 0 .1 (0) 11/12 1.33

11/8 5 .6 (4.9) 11/8 7 .6 (7.1) 11/15 1.33

11/12 NR 11/12 1.3 (0.6) 11/19 2.50

11/15 b 5.4 (1.6) 11/15 3.4 (1.6) 11/22 1.30

11/21 b 4.1 (3.1) 11/21 10.0 (8.3) 11/26 0.80

No sam p les reported from 11/21 to 1/15 11/27 2.5 (NR) 11/29 0.16

12/4 0 .7 (NR) 12/3 0 .12
Jan 15 - April 24 n = 31 reported range: 0.4-5.5 average: 1.4 at ND = 1⁄2 DL and 0.0 at ND = 0. 12/6 0 .2 (NR) 12/6 0 .04

12/11 0.2 (NR) 12/10 0.05

12/19 0.6 (NR) 12/13 0.04

12/27 0.3 (NR) 12/24 0.04

Jan 3 - April 24 n = 29 reported range: 0.2 - 4.1 average: 1.4 at ND = 1⁄2 DL and 0.0 at ND = 0. 12/27 0.06

12/31 0.11

Jan - Feb n = 17 all sam p les reported < = 0.05

a These Park Row sam p les were 24-hour sam p les; all other Park Row sam p les were 72 hour sam p les.
b These two W o rld Trade Center sam p les were actually ta ken at the Church & Vesey sam p ler, which was som e tim es used in place of the W T C Building 5 sam p ler.

DRAFT--DO NOT QUOTE OR CITE 83 October 2002Table 5. Hum a n exposure and health risk assessm ent assum p tions and results for dioxin TEQs.

Description W TC worker Office W o rker Resident

I. Exposure Assum p tions and Results
Inhalation rate, m 3 /hr 1.3 1.0 0.55 Hours/day exposed 10 10 24 Days/week exposed 5 5 7

Air m onitoring data used W T C site Park Row P ark Row Period of exposure, dates/days Sep 12- Nov 30, 57 working days Sep 17 - Nov 30, 54 working days Sep 12 - Nov 30, 79 days

Average TEQ air concentration, pg/m 3 61 4.8 4.8

Body weight, kg 70 70 70 Absorption, fraction 0.8 0.8 0.8 ADD, pg TEQ/kg-day 9.0 0.55 0.73

II. Cancer Risk Estim ates Exposure Duration, yrs 0.16 0.15 0.22 LADD, pg TEQ/kg-day 2.0*10 -2 1.2*10 -3 2.1*10 -3

Cancer Risk 3.1*10 -6 1.9*10 -7 3.6*10 -7

Percent increase over 1.4*10 -4 background risk 2.2 % < 1 % < 1 %

III. Body Burden Increases as a Measure of Potential NonCancer Risk Dissipation rate, 1/day 0.000267 1 0.000267 1 0.000267 1
Change in body burden, pg TEQ/g lipid +1.86 +0.14 +0.20

Percent increase over 18.0 pg TEQ/kg lipid background 10 % < 1 % 1 %

1 This dissipation rate corresponds to a 7.1 year half-life in the body.

DRAFT--DO NOT QUOTE OR CITE 84 October 20022 1 3

4 6

7 8 5 10

12 N 11 N

9N K e y

1 = W T C Si t e 2 = Li be r t y & Tr i n i t y 3 = C hurch & D e y 4 = A l bany & Greenw i c h 5 = B a rcl ay & W e st B r oa dw ay 6 = Li bert y & Sout h E n d 7 = A l bany & Sout h End 8 = R e ct or & Sout h End 9 = A l bany & W e st S t 10 = E P A TAG A Lab 11 = C h ambe r s St 12 = Par k R o w N = NY SD EC s a m p l e r s

= sites with very few

s a m p le s

Figure 22. Location of dioxin air m onitoring. The locations m a rked “N” are New York State Departm e nt of Environm ental Conservation ( NYSDEC) sam p lers m a intained by EPA Region 2 with analysis of the sam p les by Region 7 (Region 2/7), whereas all other sam p lers are

m a intained by EPA’s Environm ental Response Team (EPA ERT). See text for discussion of the differences in the two sets of data from these two air m onitoring team s.

DRAFT--DO NOT QUOTE OR CITE 85 October 2002IV.e. Asbestos

Asbestos is a term used to describe a fam ily of hydrated m e tal silicate m i nerals. Asbestos exhibits som e special properties, such as high tensile strength, the ability to be woven, heat stability, and resistance to attack by acid and alkali. Thus, it was widely used f o r building fireproofing insulation and other purposes during the 1960s and early 1970s. At the peak of its dem a nd, about 3000 applications or types of products were listed for asbestos. In 1973, EPA prohibited the spraying of asbestos-containing m a terial on buildings and structures for fireproofing and insulation purposes. The use of asbestos has been sharply declining for m o re than two decades. Sprayed on asbestos was used to fireproof approxim a tely the lower half of one of the W T C towers, and m a y have been used in other places in the towers as well. One of the reasons that asbestos has been so useful is that it exists in long, thin fibers that can be sprayed, woven or m i xed. The extrem ely light and aerodynam i c asbestos fibers also lead to their ability to becom e and rem a in airborne. The f i brous nature also contributes to the health ef f e cts associated with asbestos exposure.

There are six m i nerals whose fibrous form s are characterized as asbestos and that are currently regulated. All the six m i nerals also occur in non-fibrous form s and these form s are not known to cause any health effects. The six re gulated asbestos fibers include one from the serpentine f a m ily of m i nerals: chrysotile, and f i ve f r om the am phibole f a m ily: f i brous reibeckite (crocidolite), fibrous grunerite (am o site), actinolite asbestos, anthophylite asbestos, and trem olite asbestos. Inhalation of these asbestos fibers has been linked to several adverse health effects including prim arily fibrosis of the lungs (asbes tosis), benign pleural plaques and thickening, lung cancer, and m e sotheliom a(a cancer of the thin m e m b rane that surrounds the lungs and other internal organs). It also m a y increase the risk of cancer at other sites, but the evidence is not strong. Over the years the evidence has accum u lated that longer thinner “asbestiform ” fibers are of m o re concern for hum an health. The widely accepted definition of the asbestiform fiber is a particle having a length to diam eter (aspect) ratio of $ 3:1 and a length of at least $ 5 μm . The evidence is overwhelm ing that both the m i neral content and the size and shape of the fiber affects the severity of the disease. The resp irable fibers are those with the diam eter of # 3 μm

. Fibers exceeding the diam eter of 3 μm are considered to be non-respirable.

Asbestosis, a chronic, degenerative lung disease, has been docum ented am ong asbestos workers from a wide variety of industries. The disease is generally expected to be associated only with the higher levels of exposure comm only found in workplace settings (Brown et al., 1994; Case and Dufresne, 1997). Several res earchers have found that asbestosis and lung cancer are associated with cum u lative exposure to asbestos. Benign pleural plaques and thickening also have been linked to higher cum u lative exposure to asbestos (Albin et al., 1996; de Klerk et al., 1993). Both asbestosis and benign pleural plaques result in reduced breathing capacity and m o rtality. In a review of the epidem iologic evidence for asbestosis exposureresponse relationship, the W o rld Health Organi zation Task Group on Environm ental Criteria for Chrysotile Asbestos (W HO, 1998) concluded that “asbestotic changes are comm on following prolonged exposures of 5 to 20 f/m L .” These prolonged exposures corresponded to cum u lative exposure of 50 to 200 f/m L for a 10-year exposure pe riod. They also concluded that “the risk at lower exposure levels is not known.”

DRAFT--DO NOT QUOTE OR CITE 86 October 2002The m a jority of evidence indicates that lung cancer and m e sotheliom aare the m o st im portant risks associated with exposure to low levels of asbestos over a long period of tim e. There is am ple evidence that all types of asbestos have been found to be associated with lung

cancer. Several investigators have reported lung cancer m o rtality in workers exposed to chrysotile, am osite, crocidolite, anthophyllite, trem olite, and to m u ltiple fiber types. The onset of exposure to tim e of occurrence of the diseas e is known as “latency period.” As with m o st carcinogens, asbestos-related cancers have a substantially long latency period. The latency period for lung cancer has been reported to be 10 to 40 years. Most researchers have found that occurrence of lung cancer depends on the cum u lative dose as well as other underlying lung cancer risk factors (U.S. EPA, 1986c; Peto et al., 1985). Sim ilarly, several investigators have found that all types of asbestos cause m e sotheliom aof either pleura or peritoneum in adults who had occupational exposure. This finding also pe rtains to individuals who had no occupational exposure but who lived with a parent, spouse, or sibling who was an asbestos worker and presum ably carried asbestos hom e on work clothes. Mesotheliom ahas a latency period of about 30 to 40 years. Lanphear and Buncher (1992) reviewed 1,105 m e sotheliom acases in workers occupationally exposed to asbestos. They reported that 99% had a latency period >15 years and calculated a m e dian latent period of 32 years. Further details on the toxicology and epidem iology of asbestos exposure can be found in the recent ATSDR Toxicological Profile for asbestos (ATSDR, 2001).

This next section reviews the air m onitoring data for asbestos and discusses how these data relate to hum an health benchm arks developed for asbestos. The following sections discuss the analytical m e thods for m easuring asbestos in air, the health risk benchm arks that m easured air concentrations will be com p ared to, the background concentration of asbestos that can be

com p ared to the m easured values, and then the actual air data.

IV.e.1. Analytical Methods for Asbestos Ambient Air Measurements The two analytical m e thods used in analyzing the W T C air sam p les for asbestos are phase contrast light m i croscopy (PCM) and transm i ssion electron m i croscopy (TEM). PCM, although cheaper, is unable to distinguish between asbest os and nonasbestos fibers. It counts all fibrous structures with a m i nim u m diam eter of 0.3 μm and has a m a gnification range of 100 - 400X. Fibrous structures are defined as particles exhi biting a length of > 5 μm and an aspect ratio of length to width of 3:1. PCM cannot resolve inte rnal structure or distinguish the m i neralogy. PCM results are reported on a m a ss-per-volum e basis, fiber per cubic centim eter (f/cc or f/cm 3 ) or, equivalently, fiber per m illiliter (f/m L). TEM, on the other hand, is m o re expensive, but it can count the fibrous structures with a diam eter of < 0.01 μm , and it can resolve internal structure and distinguish m i neralogy. It has a m a gnification range of 5,000 - 20,000X. TEM results m a y be reported as concentrations or, for com p arison with EPA AHERA standards (see below), as structures per square m illim eter (S/mm 2 ) of f

ilter in the am bient air m onitor used. Details about the m onitoring apparatus appropriate for m easurem ent of asbestos using the TEM

m e thod and the appropriate ways to count and interpret the electron m i croscopy results are supplied in EPA (1987) and NIOSH (1994). Details about the PCM m e thod for workplace

m easurem ents can be found in NIOSH (1994) and in OSHA (1994).

TEM data, expressed on a structures per f ilter unit area basis (as listed on the EPA web site), can be converted to a concentration in air in structures per cubic centim eter. This is

DRAFT--DO NOT QUOTE OR CITE 87 October 2002accom p lished by m u ltiplying the S/m m 2 term by a conversion factor defined as the area of the f ilter paper, m m 2 , divided by the volum e of air, liters or cubic centim eters, that is drawn into the air m onitor. The AHERA Final Rule establishing a 70 S/mm 2 standard for asbestos in schools (EPA, 1987; see next section for m o re details on this benchm ark), one of the standards used in this report to evaluate the W T C data, specifies that a volum e at least 1199 L (liters; 1.199*10 6 cc) m u st be drawn into a m onitor with a 25 mm f

ilter (this filter size corresponds to an effective area of 385 m m 2 ) or that a volum e of at least 2799 L (2.799*10 6 cc) m u st be drawn into a

m onitor with a 37 mm filter (effective area of 855 mm 2 ) when applying the standard. Therefore, the conversion factors for both filters, to convert S/mm 2 to S/cc, are 0.000321 m m 2 /cc for the 25

mm filter and 0.000305 m m 2 /cc for the 37 m m filter. As a reasonable approxim a tion, all results in S/mm 2 can be converted to a volum etric S/cc basis by m u ltiplying by 3*10 -4 [S/cc]/[S/mm 2 ],

assum i ng 1200 L or 2800 L is drawn through an appropr iate filter. Using this conversion factor, the AHERA standard of 70 S/m m 2 is equivalent to 0.021 S/cc.

However, the conversion to S/cc still does not put the data on an equal footing with PCM data expressed on a f/cc basis, because “fibers” are alm o st always different from “structures”. Structures are bundles of fibers and m a ny m o re “structures” can be identified by TEM than “fibers” by PCM because TEM can identify m u ch sm aller structures. Therefore, a TEM result f o r a given air sam p le (expressed on a volum e basis, S/cc) will generally be greater than a PCM result for that sam e air sam p le (expressed as f/cc). In general there is not a good correlation between PCM and TEM m easurem ents, and the ratios of the fiber counts seen with these two

m e thods will vary according to the types of asbestos involved and the nature of the exposure setting. As noted below in m a king som e rough com p arisons, ATSDR has assum e d a ratio of 60 of

volum etric TEM data to volum etric PCM data; that is, PCM data was m u ltiplied by 60 to convert the data to TEM units by ATSDR (ATSDR, 1999). The was done for the purpose of

com p aring different data from around the c ountry to m a ke observations about background asbestos concentrations.

As m u ch of the health effects data on asbestos are expressed in term s of PCM f/cc, a useful variant of the TEM technique is to include count s of structures that would be expected to be visible under PCM and m eet PCM criteria for c ounting as fibers. Specifically, structures

m eeting a m i nim u m diam eter of >0.3 μm with length >5 μm are counted as PCM equivalent (“PCME”) fibers.

IV.e.2. Risk Assessment Benchmarks fo r Evaluation of Asbestos Air Data The principal benchm ark used in this assessm ent for evaluation of asbestos in air data from the W T C site is the Asbestos Hazard Em ergency Response Action (AHERA) standard of 70 S/mm 2

. This standard is determ ined by TEM analysis. This standard is described in the Final Rule and Notice for Asbestos-Containing Mate rials in Schools (40 CFR Part 763, October 30, 1987; cited in this report as EPA, 1987), and that rule also provides details on the m onitoring apparatus and the structure counting procedure. This counting procedure includes discussions on the am ount of filter area to exam ine with different volum es of air, and also the requirem e nt to count fibers with an aspect ratio of > 5:1 (aspect ratio = length to width ratio) and a length > 0.5 μm

. Briefly, this count of 70 S/mm 2 is specific to a m i nim u m volum e of air requirem e nt (1 2 00 L if the filter size is 25 m m , and 2800 L if the filter size is 37 m m ) , and with this volum e, a reading

DRAFT--DO NOT QUOTE OR CITE 88 October 2002of 70 S/m m 2 was evaluated as being statistically distinguishable from the count that would com e from a blank filter. That background count is about one-fourth the standard, or 17.5 S/mm 2

. The AHERA rule specifies that children would be allowed back into a school that has been undergoing asbestos abatem ent (rem oval and/or encapsulation) if the TEM readings were consistently below the count of 70 S/m m 2

. This would be evidence that the concentration was sim ilar to background readings. Alternately, an abatem ent area could be deem ed suitable for occupation if sam p les taken within the area were statistically sim ilar to sam p les sim u ltaneously taken outdoors in an asbestos-free environm ent. Details of these procedures are provided in the Final Rule, as cited above.

It should be noted that this standard is not health based, but rather technology based. It is also noted that the technology has im proved since 1987, such that current filters often have m u ch less than 17.5 S/m m 2 , som e tim es close to 0 S/mm 2

. Therefore, 70 S/m m 2 would be m u ch higher than blanks and represents m o re than just a statistical elevation above background. above. Finally it is noted that while the AHERA standard was originally intended as an indoor ‘clearance’ standard, it is being used to evaluate outdoor exposures in this assessm ent.

The current OSHA PEL is also used in this assessm ent to evaluate air concentrations of asbestos m easured using the PCM m e thod. The PEL for occupational exposures to asbestos is 0.1 f/cc by PCM averaged over an 8-hour day (OSHA, 1994). This standard is relevant for the

com p arison of exposure of rescue and other workers at the W T C site with current workplace standards. EPA also collected air sam p les analyzed for fibers by the PCM m e thod that m a y be used for this purpose.

IV.e.3. Background Air Concentrations for Asbestos ATSDR’s Toxicological Profile for Asbe stos (ATSDR, 1999) provides a sum m a ry of background asbestos levels. Because the health effects data regarding inhalation exposure to asbestos are usually expressed in term s of PCM f/cc, ATSDR chose to convert am bient air data reported in units of ng/m 3 or TEM f/cc to units of PCM f/cc. ATSDR’s sum m a ry included these crude assum p tions: 1 PCM f/cc is equal to 60 TEM f/cc and also approxim a tely equivalent to a

m a ss concentration of 30,000 ng/m 3

. (Note, however, that there was not sufficient analysis available for this current report to suggest applying these factors to asbestos m easurem ent data f o r the W T C data.)

On this basis, the following summ a ries are excerpted from the profile (specific references supplied in ATSDR, 1999). It should be noted that these “background” data are derived from settings where no identified asbestos m a terials are present, as well as other settings, such as buildings containing asbestos m a terials where there m a y have been som e local releases.

• D ata from several studies indicate that in urban areas, m o st am bient air concentrations range from 3*10 -6 to 3*10 -4 PCM f/cc, but they m a y range up to 3*10 -3 PCM f/cc as a result of local sources. In another investigation, the m e dian concentration in U.S. cities has been estim ated to be 7*10 -5 PCM f/cc.

• A recent analysis of m onitoring data for asbestos in am bient air worldwide estim ated rural and urban levels at about 1*10 -5 TEM f/cc (2*10 -7 PCM f/cc) and 1*10 -4 TEM f/cc (2*10 -6

DRAFT--DO NOT QUOTE OR CITE 89 October 2002PCM f/cc), respectively.

• I n a review of indoor air m onitoring data from a variety of locations, arithm e tic m ean concentrations ranged from 3*10 -5 to 7*10 -3 PCM f/cc. Levels of asbestos in 94 public buildings that contained asbestos range d from ND to 0.2 TEM f/cc (ND to 3*10-3 PCM f/cc), with an arithm e tic m ean concentration of 0.006 TEM f/cc (10-4 PCM f/cc). Analysis of data based on air sam p les from 198 buildings with asbestos-containing m a terials (ACM) indicated m ean asbestos levels ranging from 4*10 -5 to 2.43*10 -3 TEM f/cc (7*10 -7 to 4*10 -5 PCM f/cc).

• A sbestos concentrations in 41 schools that contained asbestos ranged from ND to 0.1 TEM f/cc (ND to 2*10 -3 PCM f/cc), with an arithm e tic m ean of 0.03 TEM f/cc (5*10 -4 PCM f/cc). Another study reported average concentrati ons of airborne asbestos fibers > 5 μm in length of 8*10 -5 TEM f/cc and 2.2*10 -4 TEM f/cc in 43 non-school buildings and 73 school buildings, respectively (the 60:1 conversion factors would not apply to these data, since the TEM readings were already on fibers >5 μm in width, so they are likely to be m o re directly

com p arable to PCM results). In another study in 71 U.S. schools, the m ean, the 95 percentile, and the m a xim u m asbestos levels were 1.7*10 -4 , 1.4*10 -3 , and 2.3*10 -3 PCM f/cc, respectively.

• A study of 49 buildings in the United States reported m ean asbestos fiber levels of 9.9*10

-
4 PCM f/cc in buildings with no ACM, 5.9*10 -4 PCM f/cc in buildings with ACM in good condition, and 7.3*10 -4 PCM f/cc in buildings with dam a ged ACM.

In general, concentrations of asbestos in both indoor and outdoor settings and in both rural and urban settings appears to be less than, and by som e studies, som e tim es substantially less than, 3*10 -3 f/cc on a PCM volum etric basis.

IV.e.4. Asbestos Air Monitoring Data at the WTC Three sources of inform ation were used to evaluate the asbestos air m onitoring. One was the EPA W T C database itself. Downloads of this database occurred in May of 2002, and the data evaluated are current as of about m i d-April, 2002. The W T C database includes

m easurem ents by several federal, state, and local agencies. The second source of data was the Trends Report dated May 16, 2002 (EPA, 2002a). There have been three Trend Reports. Generally, these reports obtain all their data from the EPA W T C database and provide

sum m a ries and interpretative analyses. The third source of data is a study comm i ssioned by a “Ground Zero Elected Officials Task Force” to principally sam p le two apartm ents on Septem ber 18, 2001 (Chatfield and Kom i nsky, 2001). Wh ile the focus of that study was on the indoor environm ent (it is reviewed in m o re detail in Section V), two outdoor air sam p les were also taken.

The May Trends Report contains a summ a ry of the PCM and TEM data collected between Septem ber 12, 2001 (the date of the first reported sam p le), and April 13, 2002, in the lower Manhattan area in the vicinity of Ground Zero. Additional TEM data from the Staten Island Landf ill were obtained directly f r om the Region 2 W T C database. Figures 23 and 24 show the locations of f

i xed m onitors at the Lower Manhattan and Staten Island Landf ill areas,

DRAFT--DO NOT QUOTE OR CITE 90 October 2002respectively. A few m o re stations were set up in public schools (Manhattan - PS143, Queens - PS199, Brooklyn - PS274, Bronx - PS154, and Staten Island - PS44), and New Jersey (4 locations). There were over 600 sam p les taken in these public schools. Nearly all the sam p les were non-detected, with only one high reading of 93.3 S/m m 2 in PS199 in Queens on October 12, 2001, and 2 other low readings (< 20 S/mm 2 ). Over 100 sam p les were reported for the New Jersey locations through early Decem ber of 2001. Nearly all readings were non-detect with a few low m easurem ents (< 20 S/m m 2 ).

On the basis of these findings, there does not appear to be any significant concern for a health im pact at these Brooklyn, upper Manhattan, and New Jersey locations, and they are not discussed further.

The latest trends report (EPA, 2002a) sum m a rizes the results of 8,870 sam p les taken from lower Manhattan and m easured for TEM (locations in Figure 23). Sam p les taken during the tim e period between Septem ber 14 (the date of the first asbestos sam p le taken) and Septem ber 30 showed generally the highest concentrations. Table 6 lists the TEM m easurem ents above 70 S/m m 2 , and, as shown, m o re readings above this level were found for Septem ber (11 readings) than for any other m onth: October (2), Novem b er (1), Decem ber (1), January (1), February (2), March (3), and April (1).

The Trends Report also presents a directional analysis that supports this general observation in m o st cases. For this directional analysis, a subset of the sites was selected to represent the north, south, east, west, northeast, northwest, southeast, and southwest quadrants. Two-week m a xim u m s were then identified for eachof these sites. These two m a xim u m s were plotted on 3-d graphs for N-S, E-W
, NE-SW
, and NW -SE. These graphs are duplicated in Figures 25 - 28 for TEM. The N-S graph in Figure 25, for exam ple, shows that m o st of the

sam p lers had their highest 2-week m a xim u m s during the first 2-week period identified, Septem ber 16 to Septem ber 30. Som e sam p lers did have additional elevations later in tim e, such as Albany and Greenwich, which had a high reading of 204 S/m m 2 in Decem ber (from Figure 25 and also listed in Table 6).

The sam e general observation that early readings were the highest is seen in the NE-SW graph of Figure 28. These two graphs also do not exhibit a predom inant wind direction: high

m easurem ents of the sam e m a gnitude were found on both the N and S sides (Figure 25) and the NE and SW sides (Figure 28). Figures 26 and 27, on W

- E and NW -SE, do not show the sam e predom inant elevations in Septem ber; concentrations are m o stly level throughout tim e, with occasional elevated readings, such as a reading of 213 S/m m 3 in February, 2002, at Church & Dey (from Figure 26 and Table 6). It does appear that during 2002, m o st readings were at what appears to be background for the area, at nondetect or reported at less than 20 S/mm 2

.

A num ber of sam p les at the Staten Islands Landf ill recorded higher levels than the AHERA standard. This presum ably results from W T C debris being unloaded at this location, which causes the asbestos structures to becom e airborne. The W T C database listed 5207 m easurem ents in num erous Staten Islands Landf ill sites (see Figure 24), and 50 sam p les were identif ied as above 70 S/m m 2

. These are listed in Table 6. Unlike the air m onitors near Ground Zero, which showed the m o st elevations in Septem ber, the m o st elevations in the landf ills occurred f a irly

DRAFT--DO NOT QUOTE OR CITE 91 October 2002uniform ly in October and Novem b er. This was perhaps a tim e period of m o st rigorous unloading. Of the 50 readings above 70 S/mm 2 , 36 occurred during these two m onths. The highest level of 275.56 S/m m 2 was observed on Novem b er 5, 2001.

The Trends Report (EPA, 2002a) sum m a rizes the results of 12,674 am bient sam p les

m easured for PCM, of which 8870 were also m easured for TEM. Figures 29 - 32 show the directional analysis results for PCM. It is noted that all sam p les were less than 0.1 f/cc. The trend observed above for TEM, that m o st high readings were found in the early readings in Septem ber, holds as well for PCM. The range of these higher m easurem ents is about 0.04 to 0.08 f/cc, and only 7 m easurem ents in this range are seen in Figures 29 - 32. As noted above, PCM analyses identify the presence of fibers, including fibers of m a terials other than asbestos. By Decem ber, the m a xim u m 2-week readings were all at apparent background for the area. W ith a few isolated exceptions, levels ranging from non detect to about 0.003 f/cc had been observed from lower Manhattan sam p ling sites since February, 2002 (EPA, 2002a). This background is consistent with the background m easurem ents in other locations summ a rized above.

Chatfield and Kom i nsky (2001) describe the sam p ling of two apartm ents one week after Septem ber 11, on Septem ber 18. In addition to sam p ling of indoor air and dust (described in Section V), and som e outdoor dust, two sam p les of outdoor air were also sam p led. One was at a residential dwelling characterized as “high”, so nam e d due to the expectation that higher concentrations would be m easured within it. It was in an apartm ent building located on 250 South End Avenue, close to and southwest of Ground Zero. Apartm ent 10D, on the east side of this building and which had sustained window da m a ge, was selected for sam p ling. Heavy dust deposits were in the apartm ent. One air sam p le at this site was taken by positioning the sam p ler outside a sliding window. The concentration of chrysotile asbestos (S > 0.5 μm ) was 548 S/mm 2 , which is the highest outdoor air m easurem ent found. However, it is likely this high reading was inf l uenced by the air quality on the inside of the apartm ent, which showed exceedingly high asbestos concentrations (>10,000 S/m m 3 ; see the discussion on this study in Section VI. Data on Occupational and Indoor Exposures), and was likely not representative of outdoor concentrations. The “low” location was located four blocks north on 45 W a rren Street. The apartm ent building did not appear to sustain any external dam a ge. Apartm ents on the second and fifth floors were sam p led. A sam p le ta ken on the roof above the fifth floor apartm ent showed a reading of 6.5 S/m m 2 chrysotile asbestos.

IV.e.5. Human Health Evaluation of Asbestos Air Measurements Only 22 of 8870 TEM m easurem ents in lower Manhattan from EPA’s W T C data base exceeded the AHERA standard of 70 S/mm 2 , and one additional sam p le (of two taken) from an independent study exceeded the standard. The 12 exceedences, which occurred in Septem ber, were all at sites bordering Ground Zero: 250 South End Ave., Barclay & W e st Broadway, Albany & Greenwich, Liberty & South End, Vesey & W e st, and Albany & W e st. These sites were still in the restricted zone during Septem ber. The sam e general trend can be seen with the PCM data. Measurem ents near to or greater than 0.04 f/cc occurred m o stly in Septem ber (6 of 7

sam p les during Septem ber, with 1 high sam p le during the first two weeks in October) and at sites bordering Ground Zero: Broadway & Liberty, Rector & South End, Albany & W e st, W e st Broadway & Barclay, W a ll & Broadway, Albany & Greenwich, and Liberty & South End. It is

DRAFT--DO NOT QUOTE OR CITE 92 October 2002reasonable to conclude that general population exposures to am bient levels of asbestos were

m i nim a l and potential short- and long-term health im pacts were m i nim a l during the early weeks when a sm all percent of elevated m easurem ents of asbestos were reported.

The potential for exposure appeared to be som e what greater at the Staten Island Landfill. A total of 50 sam p les exceeded the AHERA standard of 70 S/m m 2 , with m o st exceedences occurring during October and Novem b er. The average of the 36 exceedences during October and Novem b er was 92.6 S/m m 2

. Exceedences in February through April of 2002 were likely due to the continued unloading of W T C debris. Assum i ng the crude TEM to PCM conversion factor of 1/60 used by ATSDR and the TEM surface area to volum e conversion factor of 3*10 -4 [f/ cc]/ [ S/ mm 2 ], then this converts to a PCM-equivalent concentration of 0.0005 f/cc. This is significantly lower than the OSHA PEL of 0.1 f/cc. It is reasonable to conclude that the exposure of workers to asbestos at the Staten Island Landfill was m i nim a l and potential shortand long-term health im pacts were m i nim a l during the unloading of debris at the site.

DRAFT--DO NOT QUOTE OR CITE 93 October 2002Table 6. Locations and concentrations of asbestos exceeding the AHERA level of 70 S/m m 2

.
Location Date Concentration Date Conc

I. Landfill Locations Location 01 Landfill Apr 27 125.98 Location 02 Landfill Mar 23 170.6 Location 05 Landfill Mar 14 78.74 Location 08 Landfill Nov 5 112 Location 09-A Landfill Oct. 8 71.11 Nov 5 71.11 Oct 25 128 Nov 11 120.0 Oct 25 128 Location 09-B Landfill Oct 18 96.24 Nov 5 71.11 Location 09-C Landfill Oct 17 97.78 Location 10-A Landfill Nov 7 80 Location 11 Landfill Oct 18 96.24 Feb 6 110.24 Nov 6 80 F eb 7 170.6 Nov 7 88.89 Feb 15 78.74 Nov 17 80 Feb 16 78.74 Location 12a Landfill Oct 8 88 N ov 12 80 Oct 16 124.44 Nov 13 72 Oct 18 96.24 Nov 20 71.11 Oct 20 80 Jan 11 166.23 Oct 31 115.56 Mar 21 157.48 Nov 5 275.56 Mar 23 125.98 Nov 11 195.56 Apr 20 104.99 Location 12b Landfill Oct 25 115.56 Nov 5 106.67 Location 13 Landfill Oct 15 80 Nov 13 97.78 Oct 25 88.89 Location 14 Landfill Oct 17 80 Dec 11 104.99 Oct 26 88.89 Dec 11 104.99 Nov 7 80 A pr 3 91.86 Location 15 Landfill (m ess tent) N ov 6 90 N ov 18 97.78 Location 16 Landfill (supply tent) O ct 20 72 Nov 9 80 II. Low er Manhattan Locations 250 South End Avenue a Sep 18 548 Location A - Barclay St & W e st Broadway Sep 15 128 Sep 15 160

Location B - Church St & Dey St Feb 11 213.33 Location C - Liberty St & Trinity St Feb 5 88 Location D - Albany St & Greenwich St Sep 27 97.78 Dec 27 204.44 Sep 30 88.88 Location E - Liberty St & South End Ave Sep 16 90 Sep 30 80

Location F - Vesey St & W e st St Sep 27 71.11

94 October 2002 DRAFT--DO NOT QUOTE OR CITETable 6 . Locations and concentrations of asbestos exceeding the AHERA level of 70 S/mm2 (cont’d).

Description Date Conc Date Conc Location K - Albany & W e st St Sep 22 80 Sep 27 177.78 Sep 23 88.89 Sep 30 71.11 Location L - North Side of Stuyvesant High Nov 28 124.44

Location V - Pier 6 Bus Sign Jan 14 72 W a sh Tent - W e st St. Between Murray & Vesey Mar 9 144 Mar 30 96 Mar 29 96 Apr 2 80 Site 2 - Cham bers Street Oct 9 104.99 Public School 199 in Queens Oct 12 93.33

a This sam p le was reported on in Chatfield and Kom i nsky (2001); all other data was from the EPA W T C data base. See text for m o re detail.

DRAFT--DO NOT QUOTE OR CITE 95 October 2002Figure 23. Location of asbestos m onitoring stations in Lower Manhattan.

DRAFT--DO NOT QUOTE OR CITE 96 October 2002Figure 24. Location of Asbestos m onitoring stations in Staten Island and nearby locations in New Jersey (note: sam p ling sites in the Staten Island Landf ill identif ied only by num ber).

DRAFT--DO NOT QUOTE OR CITE 97 October 2002Figure 25. North-South directional analysis for asbestos T E M w e e k l y ma x i mu ms ( t a k e n from EPA, 2002a).

Figure 26. East-W est directional analysis for asbestos TEM weekly

ma x i mu ms ( t a k e nfr o m EPA, 2002a)

DRAFT--DO NOT QUOTE OR CITE 98 October 2002Figure 27. NorthwestSoutheast directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 28. NortheastSouthwest directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

DRAFT--DO NOT QUOTE OR CITE 99 October 2002Figure 29. North-South directional analysis for asbestos TEM weekly

ma x i mu ms ( t a k e nfr o m EPA, 2002a).

Figure 30. East-W est directional analysis for asbestos TEM weekly

ma x i mu ms ( t a k e nfr o m EPA, 2002a)

DRAFT--DO NOT QUOTE OR CITE 100 October 2002Figure 31. Northwest-Southeast directional analysis for asbestos TEM weekly m a xim u m s (taken from EPA, 2002a).

Figure 32. NortheastSouthwest directional analysis for asbestos TEM weekly

m a xim u m s (taken from EPA, 2002a).

DRAFT--DO NOT QUOTE OR CITE 101 October 2002IV.f. Volatile Organic Compounds (VOCs)

VOCs are carbon com pounds that exist exclusively in the gaseous phase in the am bient environm ent and include benzene, toluene, chlorom e thane, ethylbenzene, acetone, and styrene. VOCs have been associated with a variety of h ealth effects, including im m unologic, hem a totoxic and neurologic effects; chrom o som a l dam a ge; and cancer. VOCs are produced as a result of

com bustion of products containing carbon, such as plastics, wood, paper, carpeting, gasoline, and jet fuel. Thus, they would have been produced as a result of the W T C disaster.

Analysis of all VOCs released at the W o rld Trade Center would require evaluating hundreds of different com pounds. The list was narrowed down by em ergency response personnel, representatives from EPA headqua rters, EPA Region 2, NYSDEC, and NYSDOH. In this assessm ent, data for 14 VOCs were exam ined and screened, including acetone, benzene, 1,3 butadiene, chlorom e thane, 1,4 dioxane, etha nol, ethylbenzene, freon-22, m e thyl styrene, propylene, styrene, tetrahydrofuran, toluene, a nd xylenes. These VOCs were chosen on the basis of frequency of detection, concentration, toxic ity, and carcinogenicity. Two of these 14 VOCs, freon-22 and m e thyl styrene, were not system a tically m easured outside of Ground Zero. Freon22 was m easured only at the W T C Chiller Plant and m e thyl styrene was only m e asured at Ground Zero. For this reason, freon-22 and m e thyl styrene are not evaluated in this report. Additionally, because no screening standards are available for propylene, a health assessm ent cannot be conducted for this chem ical. Therefore, a total of eleven VOCs were evaluated for this report.
To evaluate the VOC exposures, a variety of screening benchm arks were used, including OSHA PELS and STELS, ATSDR acute and interm ediate inhalation MRLs, and EPA Superfund Technical Support Center (STSC) provisional s ubchronic RfCs. If none of these benchm arks were available, the Am erican Conference of Governm e ntal Industrial Hygienists (ACGIH) Threshold Lim it Values (TLVs) for an 8-hour exposure and the NIOSH RELS were used. The goal of this assessm ent was to evaluate effects due to short-term exposure, thus screening tools that are based upon lifetim e exposures to a chem ical (i.e. EPA RfC values or ATSDR chronic MRLs) were not used.

IV.f.1. Evaluation of VOCs at Ground Z ero The m a jority of the EPA data collected for VOCs were within Ground Zero (North Tower Center, South Tower Center, and Austin Tobin Plaza) and nearby locations. For exam ple, for acetone, benzene, ethylbenzene, and 1,3 butadiene, m o re than 500 sam p les were taken in the restricted zone near and within Ground Zero, wh ere authorized personnel were directed to wear respirators. The m a jority of the m easurem ents taken were grab sam p les that were usually collected within a 4-m i nute period. Sam p les at North Tower Center and South Tower Center were taken in potential hot spot areas such as plum es, areas of fire and com bustion, and steam releases. The efforts at these two locations were subjective and were intended to capture potential worst case em issions. Sam p les at Austin Tobin Plaza were taken at a breathing zone height, but were still grab sam p les and were not purposively where workers were currently working, but where they m i ght work or where th ere was visible sm oke to contend with. Thus, collected sam p les at the three sites cannot be considered representative of the general air quality to which workers were exposed. Rather, the principal purpose of the EPA sam p ling at Ground

DRAFT--DO NOT QUOTE OR CITE 102 October 2002Zero was to provide results within four hours to alert the Fire Departm e nt of New York (FDNY) and the contractors/union health/safety officer s working at Ground Zero about conditions that posed im m e diate health concern to the workers. This sam p ling was specifically requested by the FDNY and was conducted on a daily basis until the rem oval activities were com p leted at Ground Zero (end of May 2002).

As would be expected given this intention, som e of the results (including data for benzene, 1,3-butadiene, and styrene) did show exceedences of OSHA lim its. A few sam p les clearly dem onstrated exceptionally high m easurem ents of VOCs produced as a result of the disaster. Som e sam p les were collected on top of, and at tim es, inside the actual debris pile, clearly dem onstrating subjective sam p le design. Because the VOC sam p ling at the site is not believed to be representative of actual exposures to personnel, it would not be appropriate, or valid, to use these VOC sam p ling data to analyze worker exposures.

OSHA collected approxim a tely 700 sam p les for organic com pounds, as described in Chapter VI. Most of these sam p les were taken using personal air m onitors, and the sam p les were taken over longer periods (one to eight hours) and are representative of a worker’s breathing zone exposure. As described in Ch apter VI, the OSHA data did not show routine exceedences of screening values (the OSHA standards). For that reason, W T C worker exposures will not be evaluated further. Instead, sam p ling data that were collected at sites surrounding the W T C site were used to evaluate potential health risks to persons who live or work in surrounding

areas.

IV.f.2. Evaluation of VOCs at Sites Surrounding Ground Z ero The EPA W T C m onitoring database and data from EPA-ORD m onitors were used to evaluate VOC exposures to persons who m a y live and work in areas surrounding the W T C site. Most of the data in the W T C m onitoring database are from EPA sam p ling, but data from other groups (e.g., NYSDEC, OENHP) are also included. Data from the W T C m onitoring database covered approxim a tely 27 locations and the EPA-ORD m onitors covered 5 locations.

A m ap of the VOC sam p ling locations outside of Ground Zero is shown in Figure 33. Table 7 lists the site nam e , street address, approxim a te dates of sam p ling and the approxim a te

num ber of sam p les that were taken. Because the num ber and dates of sam p ling varied depending on the VOC, the sam p le dates and num ber of sam p les taken shown in the table are for benzene m onitoring only. These num bers are, in general, representative of the dates and frequency of sam p ling of the other VOCs.

Exceedences of benchm ark standards were seen for 6 of the 11 VOC com pounds evaluated in this assessm ent, including acetone, benzene, 1,3-butadiene, chlorom e thane, ethylbenzene, and toluene. 1,4 Dioxane, ethanol, styrene, tetra hydrofuran, and xylenes showed no exceedences of screening benchm arks at any of the sam p ling sites and are therefore not considered to be contam inants of concern at sites surrounding Ground Zero. Table 8 lists the sites that showed exceedences of screening benchm arks, the dates of exceedence, and the location of the site in relation to the restricted zone. Tables 9-14 show the exceedences of these 6 VOC com pounds.

For 5 of these 6 VOC com pounds, data were also available for 24-hour sam p les taken by

DRAFT--DO NOT QUOTE OR CITE 103 October 2002EPA; 24-hour sam p les were not available for chlorom e thane. These 24-hour sam p le results are also provided in Tables 9, 10, 11, 13, and 14 to com p are with the exceedences (Table 12 is chlorom e thane).

Chem ical-by-chem ical summ a ries of the 6 VOCs that exceeded benchm arks are presented below.

Acetone: Most people are exposed to acetone through consum er product use, including nail polish rem over, particle board, and paint rem overs. Acetone exposure m a y also occur as a byproduct of exposure to isopropyl alcohol. The typical level of acetone in the air in cities in the United States is about 0.007 ppm (ATSDR, 1994). Acute exposure to acetone at levels above 100 ppm m a y cause irritation to the nose, throat, lungs, and eyes (ATSDR, 1994).

A total of 264 acetone m onitoring results were evaluated at sites surrounding Ground Zero. A sum m a ry of the screening benchm arks and exceedences is shown in Table 9. All three exceedences were seen at Greenwich and Liberty. Two of the exceedences were on Septem ber 28, where grab sam p les found concentrations of 29 ppm and 22 ppm

. On October 1, a concentration of 20 ppm was detected. The othe r 12 sam p les taken at Greenwich and Liberty did not show concentrations above 13 ppm , including the sam p les taken on Septem ber 26 and Septem ber 27, as well as October 2, October 3, and February 23.

The m onitoring data indicate that the acetone level was found to elevated above a typical background (0.007 ppm as noted above) in grab sam p les for 4 days only on the end of Septem ber and beginning of October just off the southernportion of Ground Zero. Because this would correspond to an acute exposure, the ATSDR acute MRL screening value of 26 ppm (ATSDR, 1994) is m o st appropriate. This value was only slightly exceeded in one sam p le on 1 day (29 ppm ). The Greenwich and Liberty sam p ler location was in the restricted zone at the tim e of the exceedence and it was unlikely that residents would be present in that area.

Twenty-four hour sam p les were taken on Septem ber 27 and for three days in Decem ber. As seen in Table 9, these locations bordered Ground Zero and the day-long concentration was nearly 4 orders of m a gnitude (10,000 tim es) lower than the grab sam p les, and well within the range of the cited typical background of 0.007 ppm

. This clearly dem onstrates that sam p ling within a “hot spot” can result in very high concentrations that are representative of only the few

m i nutes during which the grab sam p le is taken .

Benz ene: Benzene is widely used in the production of other chem icals. It is also found in crude oil, gasoline, and cigarette sm oke. Excluding occupational exposures, the m a jor sources of benzene exposure are tobacco sm oke, autom obile service stations, autom obile exhaust, and industrial em issions. Urban air concentrations of benzene can vary widely, depending on m obile source pollution. One large urban study (ATSDR, 1997a) detected a m e dian benzene level of 0.013 ppm

. Background concentrations reported by EPA Region 2 for benzene are 0.00051 ppm and 0.00053 ppm (annual averages of Brooklyn and Staten Island locations, respectively, over the period 1994 - 98; EPA, 2002b).

Breathing levels of benzene above 100 ppm can cause drowsiness, dizziness, and

DRAFT--DO NOT QUOTE OR CITE 104 October 2002unconsciousness. Long-term continued exposures to benzene will depress and m a y cause dam a ge to the blood-form ing system , as seen by a decrease in red and white blood cells, lym phocytes, platelets, and other blood constituents. However, after exposure has ended, red blood cell levels m a y return to norm a l. Benzene can also harm the im m une system and increase the chances of infection and cancer. Benzene is a known hum an carcinogen, causing leukem i a. Most of what is known about the acute and chronic effects of benzene com e s from anim al and hum an studies where decreases in bone m a rrow function have been m easured. The interm ediate MRL, 0.004 ppm , was derived from a study in m i ce, where changes in locom o tor activity were seen after exposure to 0.78 ppm benzene for 2 hours a day for 30 days. A 100-fold uncertainty factor was used to derive the interm ediate MRL (ATSDR, 1997a).

A total of 332 benzene m onitoring results were evaluated at sites surrounding Ground Zero. A summ a ry of the screening benchm arks and exceedences is shown in Table 10. According to sam p ling notes for other VOCs with the sam e sam p le num ber, all these sam p les were taken at ground level, and the October 1 m easurem ent was taken at ground level in a plum e. Nine m easurem ents taken at Greenwich and Liberty between Septem ber 16 and Septem ber 26, and on October 2 and October 3, were at levels below 0.02 ppm

. From these data, it appears that exceedences did not last m o re than 5 days. Furtherm ore, these exceedences all occurred within the restricted zone. At Liberty and Trinity, the exceedence detected was 11 ppm on Septem ber 26. According to sam p ling notes for other VOCs with the sam e sam p le num ber, this m easurem ent was taken at ground level in a plum e. Measurem ents taken on Septem ber 16, Septem ber 22, Septem ber 23, and on October 26 did not show exceedences.

From these data, it appears that the exceedence did not last longer than 32 days and throughout this period was in a restricted zone. Because previous sam p ling did not show exceedences, it is likely that the m easurem ent was taken deliberately in a plum e to represent a worst-case transient exposure.

For the 262 sam p les recorded in the W T C EPA database for sites surrounding Ground Zero, the m i nim a l detection lim it was 0.02 ppm , as com p ared to the ATSDR interm ediate MRL of 0.004 ppm (ATSDR, 1997a). This m eans that the analytical m e thod could not detect benzene contam ination levels below 0.02 ppm

. Therefore, one cannot evaluate whether or not the ATSDR interm ediate MRL was exceeded because the detection level for the sam p les was higher than the interm ediate MRL. Five sam p les exceeded the ATSDR acute MRL of 0.05 ppm (ATSDR, 1997a), and these are shown in Table 10. Four sam p les had values above 0.02 ppm but below the 0.05 ppm level. The rest of the sam p les in the EPA W T C database were reported to be 0.02 ppm

. These values are not reported above. Sam p le results reported to be below 0.05 ppm (257 sam p ling results) were not screened against the interm ediate MRL.

Results from the 70 EPA-ORD sam p les show that the OSHA PEL and STEL values for benzene were never exceeded. Since these EPA-ORD sam p les did have a lower detection than the sam p les reported on in the W T C EPA database, they could be com p ared against the ATSDR interm ediate MRL of 0.004 ppm

. It was found that the ATSDR acute and interm ediate MRL values were exceeded a total of 17 tim es at 4 different sam p ling sites. At W e st Broadway and Park Place, 10 sam p les were taken between Novem b er 9, 2001, and January 3, 2002. They showed benzene levels to be below the interm ediate MRL. Additionally, exceedences at W e st

DRAFT--DO NOT QUOTE OR CITE 105 October 2002Broadway and Park Place were not found on Oc tober 15, October 16, October 17, and October 22 (the highest value was only 0.002 ppm ). The range of sam p ling results (0.002 to 0.026 ppm ) shows the tem poral variability in the benzene levels. At 290 Broadway from Novem b er 26 through January 3, 10 sam p les were taken. They showed benzene levels to be below the interm ediate MRL. At Broadway and Liberty, the sam p le taken on October 17, the only sam p le taken after the exceedence on October 8, was below the interm ediate MRL at 0.0009 ppm

. At Albany and W e st, 16 sam p les were taken between October 22 and January 3. They showed the benzene levels to be below the interm ediate MRL.

Monitoring results from the EPA-ORD sam p ling suggest that benzene never exceeded screening benchm arks f o r m o re than 45 days. At all the sites there was great tem poral variability in the sam p les. The largest gap between an exceedence of the interm ediate MRL and a value below the MRL was only 11 days at W e st Broadway and Park Place. For 290 Broadway, Broadway and Liberty, and Albany and W e st, th e first sam p les below screening benchm arks were taken Novem b er 26, Septem ber 22, and Septem ber 23, respectively. If one assum e s that exposures began Septem ber 11, the worst case exceedences of the interm ediate MRL could not have lasted longer than 45, 8, and 18 days, respectively, at 290 Broadway, Broadway and Liberty, and Albany and W e st. Thus the worst-cas e, longest possible exposure, would have been 45 days at 290 Broadway.

On the basis of data summ a rized above, it is concluded that the exceedences m easured at Liberty and Trinity, Greenwich and Liberty, W

. Broadway and Park Place, Broadway and Liberty and Albany and W e st were not a public health risk to residents. These sites were in the restricted zone or on the border of the zone, and it is unlikely that residential exposures occurred for extended periods. The sam p les taken were grab sam p les (taken within a 4 m i nute period) and are not representative of the average exposures. Sam p les taken at Liberty and Trinity and Greenwich and Liberty were purposefully taken at ground level and/or in a plum e and are not representative of average breathing zone exposures. The tem poral variability of the other

sam p les, as shown by exceedences interm ixed between days that were below screening benchm arks, also leads to the conclusion that exceedences of the Interm ediate MRL were not sustained for extended periods of tim e. For exposures lasting less than 14 days, the acute MRL is a m o re appropriate health screening benchm ark, and this value was not exceeded at these sites.

At 290 Broadway, elevated m easurem ents were found as late as October 11 (see Table 10) and exposures could have occurred, as the m easurem ent was taken in a non-restricted zone. In a worst-case scenario, the longest possible exposure would have been 45 days at this site. At this site, m easurem ents were taken on a 16 thfloor balcony. W h ether or not the VOC sam p les collected at this site are representative of the breathing zone exposures will depend on the

m e teorology and air m i xing at the site. The highest benzene value m easured at this site was 0.007 ppm and the interm ediate MRL is 0.004 ppm (ATSDR, 1997a). Adverse effects would not be expected at 0.004 ppm , and it is unlikely that adverse effects would occur at 0.007 ppm

.
The 24-hour sam p les are m o stly lower than all the grab sam p le exceedences; only the finding of 0.005 ppm at Church and Dey on Septem ber 28 approached the grab sam p les listed as exceeding the ATSDR Interm ediate MRL of 0.004 ppm

. This Church and Dey location is on the edge of Ground Zero which was also restricted on Septem ber 28. In the northwest direction on

DRAFT--DO NOT QUOTE OR CITE 106 October 2002Septem ber 28, at the Vesey and W e st and the EPA Taga Bus locations showed a very low 24- hour concentration, 0.00081 at Vesey and W e st and ND at EPA Taga Bus. This dem onstrates that concentrations were likely higher in the general direction of plum e m ovem e nt, which on Septem ber 28 was likely in the east direction.

Of all the VOC data, the benzene data does suggest that sustained concentrations above the typical New York City background could have occurred for about a m onth after Septem ber 11 outside of Ground Zero. As noted above, the background concentration reported by EPA Region 2 for benzene is about 0.0005 ppm

. Four of the nine 24-hour m easurem ents taken on Septem ber 28 exceeded this background. The grab sam p le exceedences were substantially higher than this background, and there were several exceedences above the ATSDR Interm ediate MRL of 0.004 ppm

. Wh ether or not specific health effects occurred due to exposure to benzene is unknown, but given that the exceedences and elevations above typical background were near Ground Zero and m o stly within restricted zones, the data suggests that exposures to the general population were of m i nim a l concern.

1,3-Butadiene : 1,3-Butadiene is found in autom obile exhaust, wood sm oke, and cigarette

sm oke, and in the breakdown of other m a terials. 1,3-Butadiene is alm o st always found at low levels in urban air sam p les, but it breaks down very quickly. In sunny weather, the half-life of 1,3-butadiene is only 2 hours. The m e dian concentration of 1,3-butadiene in urban air has been estim ated at approxim a tely 0.0003 ppm (ATSDR, 1993).

A total of 304 1,3-butadiene m onitoring results were evaluated at sites surrounding Ground Zero. A summ a ry of the available screening benchm arks and exceedences is shown in Table 11. One exceedence of the 1.0 ppm PEL was detected in a ground-level plum e on October 1, at 1.5 ppm

. On days preceding and following October 1 the levels of 1,3-butadiene m easured at this location were below the screening benchm ark; in fact, 10 of the 12 sam p les taken at this location were at 0.002 ppm

.
All 24-hour sam p les were non-detects for 1,3-butadiene.

Chloromethane: Chlorom e thane is always present in the air at very low levels. Most of the naturally occurring chlorom e thane com e s from chem ical reactions that occur in the oceans or that occur when m a terials such as grass, wood, charcoal, and coal are burned. Reported urban levels of chlorom e thane have been between 0.00066 and 0.00096 ppm (ATSDR, 1998). The background concentration reported by EPA Region 2 for chlorom e thane is approxim a tely 0.00029 ppm (the annual average for a Staten Island location for the period 1995-1999; EPA, 2002b).

High-level exposures - above 100 ppm - to chlorom e thane can cause nervous system dam a ge and adversely affect the liver, kidney, and heart. Lower-level exposures - above 50 ppm

- have been shown to cause delayed growth, liver changes, and neurological effects in anim als. Data do not exist to determ ine health effects that would be seen with short-term , very low-level exposures. The EPA-STSC provisional subchroni c RfC, the screening benchm ark with the lowest acceptable exposure lim it, is based on a 2-year anim al study that showed neurological effects and liver and kidney dam a ge at 1000 ppm but not at 225 ppm (EPA, 1998).

DRAFT--DO NOT QUOTE OR CITE 107 October 2002A total of 257 chlorom e thane m onitoring results were evaluated at sites surrounding Ground Zero. A summ a ry of the available screening benchm arks and exceedences is shown in Table 12. As with all VOCs, all grab sam p le exceedences were taken in a restricted zone, and in the tim e f r am e f r om late Septem ber to early October. It is noted that all of the sam p les that showed exceedences at Greenwich and Liberty were taken at ground level and that the October 1

m easurem ent was taken at ground level in a plum e. Measurem ents taken at this site Septem ber 24 - 27 and on October 2 and 3 were all at levels below 0.02 ppm

. From these data, it appears that exceedences did not last m o re than 4 days. At Liberty and Trinity, the exceedence detected was 0.82 ppm on Septem ber 26, and it was noted that this m easurem ent was taken at ground level in a plum e. Measurem ents taken on Septem ber 22, Septem ber 23, and on October 26 did not show exceedences.

Ethylbenz e ne : E thylbenzene occurs naturally in petroleum and coal tar and can be released into the air from burning oil, gas, and coal The m e dian level of ethylbenzene in city and suburban air is about 0.00062 ppm (ATSDR, 1999).

Breathing high levels of ethylbenzene (above 100 ppm ) can cause dizziness, tightness in the chest, and eye and throat irritation. Short-term exposure of laboratory anim als to high concentrations of ethylbenzene in air m a y cause liver and kidney dam a ge, nervous system changes, and blood changes. No data exist to evaluate the short-term effects of low levels of ethylbenzene exposure in hum ans or anim als. The EPA-STSC provisional subchronic RfC for ethylbenzene is adopted directly from the EPA RfC for a lifetim e exposure. The EPA-STSC confidence level in this derivation is low. The EPA RfC is based on developm ental effects seen in fem a le rats that were exposed to ethylbenzene throughout their pregnancy. Adverse effects in this study were not seen at levels below 100 ppm (EPA, 1999a).

A total of 338 ethylbenzene m onitoring results were evaluated at sites surrounding Ground Zero. A summ a ry of the available screening benchm arks and exceedences is shown in Table 13. As with the other VOCs, exceedences occurred in the restricted zone in the latter part of Septem ber and early October. A value of 0.4 ppm ethylbenzene was detected at Liberty and Trinity and it was noted that this sam p le was taken in a ground-level plum e. Three sam p les obtained between Septem ber 16 and Septem ber 23 and a breathing zone sam p le taken on October 26 were all below 0.05 ppm

. The 24-hour ethylbenzene sam p les that were detected were three orders of m a gnitude (1000 tim es) lower than these grab sam p le exceedences; 10 out of 13 sam p les were non-detected. This dem onstrates again the difference between grab sam p les taken within a plum e and the 24- hour average concentration of the VOC.

Toluene : T oluene occurs naturally in crude oil and is added to gasoline. Toluene is also used in m a king paints, paint thinners, fingernail polish, lacquers, and adhesives. It can also be detected in cigarette sm oke. Urban concentrations of toluene have been estim ated to be around 0.003 ppm (ATSDR, 2000b). The background concentration reported by EPA Region 2 for toluene is approxim a tely 0.002 ppm (annual average for a Brooklyn location over the period 1994 - 1998).

DRAFT--DO NOT QUOTE OR CITE 108 October 2002High-level exposures to toluene (above 100 ppm ) m a y affect the nervous system and kidneys. Headaches, confusion, and sleepiness are also seen after high-level exposures. A shortterm exposure study (4 days) in hum an subjects showed eye and nose irritation and neurological effects at 100 ppm ; these effects were not seen at 40 ppm

. The EPA-STSC provisional subchronic RfC for toluene is adopted directly from the EPA RfC for a lifetim e exposure. The EPA-STSC confidence in this value is m e dium

. This value is derived from a study where workers were exposed to 88 ppm of toluene for 6 years. In this study, adverse neurological effects were seen in the workers (EPA, 1999b).

A total of 335 toluene m onitoring results were evaluated at sites surrounding Ground Zero. A sum m a ry of the available screening benchm arks and exceedences is shown in Table 14. The available benchm arks that were exceeded were the ATSDR acute MRL of 1 ppmand the EPASTSC provisional subchronic RfC of 0.25 ppm

. AtGreenwich and Liberty, m easurem ents taken on Septem ber 28 were collected in ground-level grab sam p les; on October 1, the sam p le was taken in a ground-level plum e. Measurem ents taken at this site on Septem ber 16 through Septem ber 27 and on Oct 2 and 3 were all at levels below 0.02 ppm

. From these data, it appears that exceedences did not last m o re than 4 days. At Liberty and Trinity, the Septem ber 26 sam p le was collected in a ground level plum e. Four sam p les obtained between Septem ber 16 and Septem ber 23 and a breathing zone sam p le taken October 26 were all below 0.05 ppm

.
The 24-hour toluene sam p les were three orders of m a gnitude (1000 tim es) lower than these grab sam p le exceedences. Sim ilar to ethylbenzene, 1,3-butadiene, and acetone, this difference in toluene concentrations between the grab sam p le exceedences and the 24-hour sam p les dem onstrates the difference between grab sam p les taken within a plum e and the long-term average concentration of the VOC.

Findings from VOC monitoring: As discussed above, m o st of the sam p les that showed exceedences were short duration grab sam p les that were taken in a plum e or at ground level, not in the breathing zone. In fact, the exceedences for benzene, ethylbenzene, chlorom e thane and toluene m easured at Liberty and Trinity on Septem ber 26, all cam e from the sam e collected grab

sam p le which was taken in a plum e. Sim ilarly, all the exceedences m easured at Greenwich and Liberty for acetone, 1,3-butadiene, benzene, chlorom e thane and toluene, cam e from the sam e 3 collected grab sam p les. Because these are 4-m i nute grab sam p les, it is not known how long the plum e lasted - from m i nutes to hours to days. These exceedences all occurred in late Septem ber and early October; available grab sam p le data before and after these exceedences are all lower in value. In addition to being grab sam p les, all exceedences occurred within restricted zones or just on the border of the restricted zones. Finally, all 24-hour sam p les of four of the VOCs ­ ethylbenzene, 1,3-butadiene, acetone, and toluene - were lower than the grab sam p les, by about a factor of 1000. On the basis of the available m onitoring data, it is concluded that the exceedences of the screening benchm arks in the restricted zone did not represent a public health risk to persons living or working at sites surrounding Ground Zero for at least these four VOCs.

The data f o r benzene was not as def i nitive. W h en com p ared with the other VOCs, the 24- hour benzene sam p les were m easured at levels that were closer in m a gnitude to the grab sam p le exceedences, within a factor of 10. This would suggest that the grab sam p le concentrations were

DRAFT--DO NOT QUOTE OR CITE 109 October 2002closer to sustained concentrations rather than short-term plum e concentrations only. Also, these 24-hour concentrations were near the ATSDR Interm ediate MRL of 0.004 ppm and higher than the historical average for New York City of about 0.0005 ppm

. The data suggests that the exposures to benzene at levels that approach the MRL were no longer than 45 days. W h ether or not specific health effects occurred due to exposure to benzene is unknown, but given that the exceedences and elevations above typical background were near Ground Zero and m o stly within restricted zones, the data suggests that exposures to the general population were of m i nim a l

concern.

DRAFT--DO NOT QUOTE OR CITE 110 October 2002Table 7. VOC sam p ling locations outside of Ground Zero.

ORD Site A W . Broadway & Park Place Sept 22- Jan 3 22

ORD Site B 290 Broadway Sept 25-Jan 3 14

ORD Site C B roadway & Liberty S ept 23-Oct 17 6

ORD Site C ’ Cedar & Trinity Nov 7-Nov 12 4

ORD Site K A lbany & W e st Sept 23-Jan 3 24 140 Broadway Sept 28 6

75 Park Place & Greenwich Sept 28 8 Albany & W a shington Sept 16 2 Church & Vessey F eb 13 2 Greenwich & Liberty S ept 16-Feb 23 15 Liberty & Trinity Sept 12-Sept 26 6 Liberty & W e st Sept 16-Oct 5 10

Loc A B arclay & W Broadway Sept 22-Sept 27 3

Loc B C hurch & Dey S ept 16-Oct 10 3

Loc C B roadway & Liberty S ept 27 1

Loc D A lbany & Greenwich Sept 27 1

Loc E L iberty & South End S ept 27 1

Loc F V essey & W e st Sept 16-Sept 27 2

Loc K A lbany & W e st Sept 23-Sept 25 2

Loc N P ier 25 (southside) Oct 13 1

Loc P A lbany & South End S ept 27 1 Number of Samples Taken Sampling Dates for Benz ene Street Location Site Name

DRAFT--DO NOT QUOTE OR CITE 111 October 2002Table 7. VOC Sam p ling Locations Outside of Ground Zero (cont’d).

Site Name Street Location Sampling Dates for Benz ene Number of Samples Taken

Loc R E PA TAGA Bus S ept 23-Jan 1 11

Loc S R ector Pl & South End S ept 27 1
Murray St & W Broadway Oct 12-Oct 14 3 Murray St betw W e st & N End N ov 5-Mar 31 134

Rockefeller Park Sept 18-Nov 7 37 Park Pl (225 Rector) S ept 28 6 Park Row & Spruce Oct 14 1

Site 1 (NYSDEC) Park Row O ct 12-Oct 13 2

Site 16 290 Broadway Sept 25 1

130 W e st (Verizon Building) Sept 29 1 South of Building 4 S ept 25 1

DRAFT--DO NOT QUOTE OR CITE 112 October 2002Table 8. Locations that showed exceedences of screening benchm arks for VOCs and restrictions to access.

Location Dates of Exceedence Restrictions to Access

West Broadw ay and Park Place Sept 22, Sept 25, Oct 3, Oct 9, Oct 19, Oct 20, Oct 21, Oct 24 in the restricted zone until Sept 27, was a border of the restricted zone until Oct 24

290 Broadw ay Sept 25, Sept 26, Sept 27, Oct 11 in the restricted zone until Sept 19

Broadw ay and Liberty Sept 23, Oct 8 i n the restricted zone until Jan 28

Albany and West Oct 1, Oct 20 was in the restricted zone until Oct 24, and becam e, and still is, a border of the restricted zone as of May 8
Liberty and Trinity Sept 26 was in the restricted zone until Feb 12, and becam e, and still is, a border of the restricted zone as of May 8

Greenw i ch and Liberty Sept 27, Sept 28, Oct 1 s till in the restricted zone as of May 8

DRAFT--DO NOT QUOTE OR CITE 113 October 2002Table 9. Acetone grab sam p le exceedences and 24-hour sam p le m onitoring summ a ry.

I. Grab Samples

Acetone Screening Benchmarks Exceedence concentration E xceedence Location and Date Restricted Zo n e OSHA PEL 1000 ppm 1 None

ATSDR Acute MRL 26 ppm 2 29 ppm Greenwich and Liberty Sept 28 Yes

ATSDR Interm ediate MRL 13 ppm 2 22 ppm 20 ppm Greenwich and Liberty Sept 28 Greenwich and Liberty Oct 1 Yes Yes

II. 24-Hour Samples

Location Concentration (ppm) D ate Albany and Greenwich 0.0064 Sep 27 Albany and South End 0.0066 Sep 27 Barclay and W e st Broadway 0.0071 Sep 27 Church & Dey 0.0078 Sep 27
EPA Taga Bus 0.012 0.0056 0.0040 0.0044 0.0048 Sep 27 Sep 27 Dec 3 Dec 10 Dec 17 Liberty and Broadway 0.0053 Sep 27 Liberty and South End 0.010 Sep 27

Rector and South End 0.0069 Sep 27 Vesey and W e st 0.0045 Sep 27

1 NIOSH (2002)

2 ATSDR (1994)

DRAFT--DO NOT QUOTE OR CITE 114 October 2002Table 10. Benzene grab sa m p le exceedences and 24-hour sa m p le m onitoring su m m a ry.

OSHA PEL 1 ppm 1 OSHA STEL 5 ppm 1 11 ppm 19 ppm 49 ppm 1.3 ppm Liberty and Trinity Sept 26 Greenwich and Liberty Sept 28 Greenwich and Liberty Sept 28 Greenwich and Liberty Oct 1 Yes Yes Yes Yes

ATSDR Acute MRL 0.05 ppm 2 0.1 ppm Greenwich and Liberty Sept 27

sam p les noted above also exceed the ATSDR acute MRL Yes

ATSDR Interm ediate MRL 0.004 ppm 2 0.011 ppm 0.024 ppm 0.026 ppm 0.007 ppm 0.012 ppm 0.008 ppm 0.016 ppm 0.008 ppm 0.005 ppm 0.007 ppm 0.0043 ppm 0.005 ppm 0.021 ppm 0.007 ppm 0.024 ppm 0.008 ppm 0.008 ppm W

. Broadway and Park Pl. Sept 22 W

. Broadway and Park Pl. Sept 25 W

. Broadway and Park Pl. Oct 3 W

. Broadway and Park Pl. Oct 9 W

. Broadway and Park Pl. Oct 19 W

. Broadway and Park Pl. Oct 20 W

. Broadway and Park Pl. Oct 21 W

. Broadway and Park Pl. Oct 24 290 Broadway Sept 25 290 Broadway, Sept 26 290 Broadway, Sept 27 290 Broadway Oct 11 Broadway and Liberty Sept 23 Broadway and Liberty Oct 8 Albany and W e st Sept 30 Albany and W e st Oct 1 Albany and W e st Oct 20 Yes Yes Border Border Border Border Border Border

No No No No Yes Yes Yes Yes Yes

II. 24-Hour Samples

Location Concentration (ppm) D ate Barclay and W e st Broadway 0.0025 Sep 27 Vesey and W e st 0.00081 Sep 27 Liberty and South End < 0.0007 Sep 27 Albany and South End < 0.0007 Sep 27

Rector and South End < 0.0007 Sep 27

DRAFT--DO NOT QUOTE OR CITE 115 October 2002 I. Grab Samples

E xceedence Location and Date Exceedence Concentration Benz ene Screening Benchmarks Restricted Zo n eTable 10. Benzene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry (cont’d).

II. 24-Hour Samples

Location Concentration (ppm) D ate Church and Dey 0.005 Sep 27 Liberty and Broadway 0.002 Sep 27 Albany and Greenwich <0.0007 Sep 27 EPA Taga Lab < 0.0007 <0.0007 <0.0007 0.0007 0.0007 Sep 27 Sep 27 Dec 3 Dec 10 Dec 17

1 NIOSH (2002)

2 ATSDR (1997)

DRAFT--DO NOT QUOTE OR CITE 116 October 2002Table 11. 1,3-Butadiene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

I. Grab Samples
1,3-Butadiene Screening Benchmarks Exceedence Concentration E xceedence Location and Date Restricted Zo n e

OSHA PEL 1 ppm 1 OSHA STEL 5 ppm 1 1.5 ppm Greenwich and Liberty Oct 1 Y es

II. 24-Hour Samples

Location Concentration (ppm) D ate Albany and Greenwich <0.0028 Sep 27 Albany and South End < 0.0027 Sep 27 Barclay and W e st Broadway <0.0027 Sep 27 Church & Dey < 0.0026 Sep 27
EPA Taga Bus < 0.0027 <0.0026 <0.0034 <0.0027 <0.0026 Sep 27 Sep 27 Dec 3 Dec 10 Dec 17 Liberty and Broadway <0.0027 Sep 27 Liberty and South End < 0.0027 Sep 27

Rector and South End < 0.0027 Sep 27 Vesey and W e st <0.0027 Sep 27

1 NIOSH (2002)

DRAFT--DO NOT QUOTE OR CITE 117 October 2002Table 12. Chlorom e thane grab sam p le exceedences m onitoring summ a ry.

EPA (1998) Chloromethane Screening Benchmarks Exceedence Concentration E xceedence Location and Date Restricted Zo n e

OSHA PEL 100 ppm 1 None

ATSDR Acute MRL 0.5 ppm 2 8.3 ppm 11 ppm 17 ppm 0.82 ppm Greenwich and Liberty Sept 28 Greenwich and Liberty Sept 28 Greenwich and Liberty Oct 1 Liberty and Trinity, Sept 26 Yes Yes Yes Yes

ATSDR Interm ediate MRL 0.2 ppm 2 sam e as above

EPA-STSC Provisional Subchronic RfC 0.14 ppm 3 sam e as above

1 NIOSH (2002)

2 ATSDR (1998)

3

DRAFT--DO NOT QUOTE OR CITE 118 October 2002Table 13. Ethylbenzene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

I. Grab Samples
Ethylbenz e ne Screening Benchmarks Exceedence Concentration Exceedence Location and Date Restricted Zo n e OSHA PEL 100 ppm 1 None

ATSDR Interm ediate MRL 1 ppm 2 4.0 ppm 4.7 ppm 1.7 ppm Liberty and Greenwich Sep 28 Liberty and Greenwich Sep 28 Liberty and Greenwich Oct 1 Yes

EPA-STSC Provisional Subchronic RfC 0.23 ppm 3 0.4 ppm sam e as above Liberty and Trinity Sept 26 Yes

II. 24-Hour Samples

Location Concentration (ppm) D ate Albany and Greenwich <0.0007 Sep 27 Albany and South End < 0.0007 Sep 27 Barclay and W e st Broadway 0.0011 Sep 27 Church & Dey 0.0022 Sep 27
EPA Taga Bus < 0.0007 <0.0007 <0.0009 <0.0007 <0.0007 Sep 27 Sep 27 Dec 3 Dec 10 Dec 17 Liberty and Broadway 0.001 Sep 27 Liberty and South End < 0.0007 Sep 27

Rector and South End < 0.0007 Sep 27 Vesey and W e st <0.0007 Sep 27

1 NIOSH (2002)

2 ATSDR (1999)

3 EPA (1999a)

DRAFT--DO NOT QUOTE OR CITE 119 October 2002Table 14. Toluene grab sam p le exceedences and 24-hour sam p le m onitoring sum m a ry.

I. Grab Samples

Toluene Screening Benchmarks Exceedence Concentration Exceedence Location and Date Restricted Zo n e OSHA PEL 200 ppm 1 None

ATSDR Acute MRL 1 ppm 2 7.5 ppm 9.0 ppm 3.7 ppm 1.8 ppm Greenwich and Liberty Sept 28 Greenwich and Liberty Sept 28 Greenwich and Liberty Oct 1 Liberty and Trinity Sept 26 Yes Yes Yes Yes

EPA-STSC Provisional Subchronic RfC 0.25 ppm 3 sam e as above

II. 24-Hour Samples

Location Concentration (ppm) D ate Albany and Greenwich 0.0014 Sep 27 Albany and South End 0.0019 Sep 27 Barclay and W e st Broadway 0.0020 Sep 27 Church & Dey 0.0033 Sep 27
EPA Taga Bus 0.0009 0.0007 0.0018 0.0017 0.0015 Sep 27 Sep 27 Dec 3 Dec 10 Dec 17 Liberty and Broadway 0.0019 Sep 27 Liberty and South End 0.0014 Sep 27

Rector and South End 0.001 Sep 27 Vesey and W e st 0.0015 Sep 27

1 NIOSH (2002)

2 ATSDR (2002b)

3 EPA (1999b)

DRAFT--DO NOT QUOTE OR CITE 120 October 200213 = Al b a ny & Sout h En d 14 = Lib e rt y & So uth En d 15 = V e ss ey & W e st 16 = 130 West (Verizon bldg) 17 = Murray St ( b etw e en We st & Nor t h End) 18 = R o ck ef e lle r P a rk 19 = EPA Taga Bus 20 = Barclay & W e st Broad w a y 21 = Pier 25 22 = Murray & W e st B r oad w a y 23 = 75 Park Place & Green w ich 24 = Ch ur ch & Ve s s e y 25 = Par k Ro w & Spruce 26 = Park Ro w 27 = 290 Broad w a y 28 = West Broad way a n d Park Place 13 = Al b a ny & Sout h En d 14 = Lib e rt y & So uth En d 15 = V e ss ey & W e st 16 = 130 West (Verizon bldg) 17 = Murray St ( b etw e en We st & Nor t h End) 18 = R o ck ef e lle r P a rk 19 = EPA Taga Bus 20 = Barclay & W e st Broad w a y 21 = Pier 25 22 = Murray & W e st B r oad w a y 23 = 75 Park Place & Green w ich 24 = Ch ur ch & Ve s s e y 25 = Par k Ro w & Spruce 26 = Park Ro w 27 = 290 Broad w a y 28 = West Broad way a n d Park Place 1

3 6 7 8 9

10 14

12 2 15 16

19

17 20

13

18

25 21

22 27

26

4 5 11 23

24 28 

### Key

1 = C h urch & Dey 2 = L i bert y & Trinit y 3 = B r oad w a y & L i bert y 4 = 1 40 Broad w a y 5 = C e d a r & T r in ity 6 = A l bany & Gre e n w ich 7 = A l bany & Wa shington 8 = A l bany & We st 9 = Gr ee n w i c h & Li ber t y 10 y & W e st 11 12 = Rect or & Sout h E n d = Libert = 225 Rector Place

Figure 33. Location of VOC m onitoring stations outside Ground Zero. 

### Key

1 = C h urch & Dey 2 = L i bert y & Trinit y 3 = B r oad w a y & L i bert y 4 = 1 40 Broad w a y 5 = C e d a r & T r in ity 6 = A l bany & Gre e n w ich 7 = A l bany & Wa shington 8 = A l bany & We st 9 = Gr ee n w i c h & Li ber t y 10 = Libert y & W e st 11 = 225 Rector Place 12 = Rect or & Sout h E n d

DRAFT--DO NOT QUOTE OR CITE 121 October 2002

### Section V. Comment on the First Several Days After September 11

An event such as Septem ber 11 dem onstrates that the greatest environm ental im pacts occur in the first 24 to 48 hours and in areas close to the site. Difficulties associated with site access and security, power supply sources, equipm ent availability and analytical capacity hindered efforts by EPA and the New York State Depart m e nt of Environm ental Conservation (NYSDEC) to put air m onitors in place im m e diately after the attack. Region 2 collected num erous sam p les of dust on Septem ber 11 and the next few days, and analyzed them for asbestos and lead. However, the first air sam p les of som e of the critical contam inants from Ground Zero and nearby were not taken until Septem ber 14, such as asbestos, while other contam inants were not sam p led until Septem ber 23, such as dioxin. Rapid initiation of m onitoring will allow the m easurem ent of air concentrations that can be very im portant for evaluation of inhalation exposures and potential short and long-term hum an health im pacts.
Therefore, very little data are available to quantify exposures which could have occurred in the hours and days following the collapse of the W T C towers on Septem ber 11. As discussed in all of the individual contam inant sections, the general trend was that air concentrations were elevated in the earliest sam p les, and that concentrations appeared to return to background within weeks to a few m onths. The section on particulate m a tter (PM) went further by speculating on what the air concentrations of PM m i ght have been in the initial plum e cloud that occurred on Septem ber 11, based on an em pirical relationship between visibility and PM concentration. The PM section also included discussions on th e findings published by Lioy et al. (2002), who

sam p led dust which had settled onto cars and other surfaces, and had been undisturbed when their sam p ling occurred a few days after Septem ber 11. The USGS has sim ilarly sam p led and reported on m easurem ents of contam inants in dust and debris (http://speclab.cr.usgs.gov/wtc/). Modeling studies within EPA to evaluate the m ovem e nt of plum es in the few days after Septem ber 11 are ongoing (prelim inary results are presented in the PM section), and these m a y shed light on exposures which could have occurred during these few critical days. Epidem iological studies m a y also elucidate in form ation on exposures during the first few days after Septem ber 11.

It seem s apparent that higher concentrations would have been found in the tim e fram e of about Septem ber 11 to Septem ber 18 com p ared to the concentrations that were found when

m onitors did get in place. The earliest am bient m onitoring data within Ground Zero and in the closest m onitors are the asbestos sam p ling results which were m easured first on Septem ber 14. Benzene and PCB m easurem ents were reported for Septem ber 16. Lead was reported starting on Septem ber 18, and PM 2.5 was reported first on Septem ber 21. The first m e asurem ents for dioxinlike com pounds were not available until Septem ber 23.

Table 15 lists the first m easurem ents on dioxin, asbestos, and lead in sam p lers within Ground Zero (the “W TC” sam p ler) and at locations bordering Ground Zero (e.g., Church & Dey). The data on that table supports the hypothesis that higher concentrations were likely to have been present within the first few days after Septem ber 11 as com p ared to when m onitoring did begin. As seen, generally the highest concentrations were the very first ones available or within the first week or two of sam p ling. It is also noted that for dioxin and lead, the m onitoring stations on South End Avenue (Liberty & Sout h End, Albany & South End, and Rector & South

DRAFT--DO NOT QUOTE OR CITE 122 October 2002End) were showing very low background m easurem ents on these first days of sam p ling at the

sam e tim e the sam p lers within the plum e - the W T C sam p ler and the Church & Dey sam p ler - were showing very high concentrations.

These data and sim ilar data for other contam inants underscore the im portance of being able to m onitor very early after such an event. It is also recognized that a m a jor uncertainty for the evaluations presented in this report is the lack of inform ation on exposures which could have occurred within that first critical week after Septem ber 11.

DRAFT--DO NOT QUOTE OR CITE 123 October 2002Table 14. Summ a ry of the first m easurem ents of dioxin TEQs, asbestos, and lead at locations within or very near Ground Zero.

Contaminant C oncentration; Location; Sampling Date Later Measurements and Other Comments

Dioxin TEQ, pg/m 3 160 W T C 9/23 170 W T C 10/2 170 W T C 10/4 All subsequent m easurem ents were less than 100 pg TEQ/m 3 through 5/28/02. Note: Upwind m onitors on South End (Liberty, Albany and Rector) all showed NDs on 9/23, indicating that elevations were tied to plum e.

130 Church/Dey 9/23 No further sam p les > 10 pg/m 3 ; sam p les through 5/17/02

100 Liberty/Broadway 9/23 No further sam p les > 10 pg/m3 ; sam p les through 10/26/01
Asbestos, S/mm 2 160 Barclay/W Broadway 9/14 ND Barclay/W Broadway 9/15 128 Barclay/W Broadway 9/15 All subsequent Barclay/W Broadway lower than 100 S/mm 2

.

80 Albany/W e st 9/22 89 Albany/W e st 9/23 178 Albany/W e st 9/27 71 Albany/W e st 9/30 Concentrations were less than 70 S/mm 2 on Sep. 17, 18, 20, and 21, but no m easurem ents above 70 after 9/30.

48 Liberty/S. End 9/14 90 Liberty/S. End 9/15 (dup) 53 Liberty/S. End 9/15 80 Liberty/S. End 9/30 There were m easurem ents between 9/15 and 9/30 that were less than 50 S/m m

2 , but no m easurem ents after 9/30 above 50 S/mm2

Asbestos a
, f/cc 0.1 Fulton/Church 9/13 0.078 Fulton/Church 9/26 0.059 Fulton/Church 9/28 All subsequent m easurem ents after 9/28 were under 0. 04 f/cc (through 8/03/02), but 6 sam p les between 9/15 and 9/19 were between 0.020 and 0.034, and sam p les on 10/1 and 10/3 were at 0.035 and 0.023, respectively.

0.035 Vesey b 9/16 0.024 Veseyb 9/17 Next sam p les on 10/6-10/9 were between 0.008 and 0.023;

no sam p les taken after 10/9.

0.035 Fulton c 9/15 0.030 Fulton c 9/16 One sam p le on 9/14 was below LOQ; no sam p les taken after 9/16.

0.020 Liberty/Church 9/14 0.021 Liberty/Church 9/18 One sam p le on 9/14 was below LOQ; no sam p les taken after 9/18.

Lead, μ g/m 3 4.3 Barclay/W

. Broadway 9/23 2.8 Barclay/W

. Broadway 9/27 One sam p le > 1.0 μ g/m 3 on 10/4, otherwise, all sam p les < 0.6 μ g/m 3 ; sam p les through 2/5/02

1.9 Church/Dey 9/18 1.7 Church/Dey 9/23 all other < 0.7 μ g/m 3 ; sam p les through 2/5/02.

5.4 W T C 9/23 next sam p le at W T C on 10/2 was 1.1, and one other 1.1 on 10/15, but otherwise all sam p les < 0.8 through 2/5/02. Sim ilar to dioxin, all South End sam p ling locations had very low findings in initial 9/23 sam p les.

a All of these sam p les taken by and reported by the NYCDEP.
b Actual location was described as, Vesey between Church and Broadway.

c Actual location was described as, Fulton between Church and Broadway.

DRAFT--DO NOT QUOTE OR CITE 124 October 2002

### Section VI. Data on Indoor and Occupational Exposures

This section provides a summ a ry of data that are available, or that are being generated, from Ground Zero sites where rescue, clean-up and other workers m a y have been present, and on the indoor air environm ent. The occupational exposure data are related directly only to the workers on Ground Zero who were potentially exposed to contam inants generated during the course of their work . The indoor exposure datarelate to residents in buildings off of Ground Zero whose exposure is from contam inated air that m a y have infiltrated their living or working spaces during or at som e point after the disaster. It is em phasized that this section does not provide any hum an health risk evaluations in the way that am bient air data were evaluated in Section IV, except when summ a rizing conclusions of the original authors of the data.

VI.a. Data From Ground Z ero Relating to Occupational Exposures The Occupational Saf e ty and Health Agency (OSHA) and the National Institute f o r Occupational Safety and Health (NIOSH) have generated data sets on air quality at Ground Zero. These data sets are summ a rized below. Further inform ation on the data and the evaluation of these data can be obtained through the web sites that are identified below.

As part of the evaluations contained in this report, exposures to PCBs and dioxin toxic equivalent (TEQ) concentrations that were m easured at Ground Zero were evaluated for on-site workers, which could include workers involve d in rescue and clean-up operations. That evaluation is summ a rized here, with reference to the m o re detailed evaluations in Sections IV.

VI.a.1. OSHA Data The OSHA data are posted on their Ground Zero m onitoring web-site, at http://www.osha.gov/nyc-disaster/sum m a ry.htm l

. Further inform ation on these data can be obtained from OSHA, with contacts provide d at, http://www.osha.gov. No interpretative analysis of the OSHA data, other than an id entification of exceedences of benchm arks, is provided on the web site or from other available sources.

A total of 1434 asbestos sam p les (excluding bulk and blank sam p les) were taken. From Septem ber 19-21, 177 sam p les were taken in the financial district. Since Septem ber 21,

sam p ling focused on the W T C site and those workers working in or imm e diately next to it. A total of 179 of the sam p les analyzed exceeded OSHA' s PEL of 0.1 f/cc. However, upon further analysis using discrim i nating counting m e thods and/or TEM analysis, the num ber of asbestos fibers found dropped dram atically to below detectable levels or well below 0.1 f/cc.

The web site also summ a rizes data taken on CO, total dust, respirable silica, several organic com pounds including PCBs, PAHs, di oxins, VOCs, and others, freon-22, hydrogen fluoride, phosgene, inorganic acids, oxides of n itrogen/sulfur, m e tals including lead, m e rcury, arsenic, and others, ionizing radiation, and noise

. The web site indicates very few exceedences of OSHA PELs or other relevant benchm arks.

The results for respirable silica suggested som e exposure. Of 1353 silica sam p les, 94 exceeded the PEL. The highest sam p le result was approxim a tely twenty-one tim es the OSHA lim it (jack hamm e ring concrete 16 feet below grade). The other elevated exposures were

DRAFT--DO NOT QUOTE OR CITE 125 October 2002approxim a tely one to fourteen tim es the OSHA lim it. These exposures occurred during: 1) pre-drilling /slurry wall 2) jack hamm e ring, 3) rubble rem oval and loading operations near the W i nter Garden; 4) during the breaking up of concrete in the pit; 5) while drilling the concrete slurry wall, 6) flagging operations in pit, and 7) while chipping concrete with power tools during dem o lition activities at 7 W T C' s parking garage. Most of the work areas where apparent overexposures to silica occurred were in the rubble pile/pit.

Sim ilar to other results, very few exceedences of organic com pounds were identified, including one exceedence for the benzene OSHA Allowable Lim it of 1 ppm , and 8 PAH exceedences of OSHA' s coal tar pitch volatile PEL of 0.2 m g /m 3

.

For m e tals, OSHA took a total of 1331 sam p les (excluding bulk and blank sam p les) to

m onitor worker exposures to dusts, fum e s, oxides, and other com pounds of m e tals such as antim ony, beryllium
, chrom i um , cobalt, copper, iron, lead, m a nganese, m e rcury, m o lybdenum
, nickel, vanadium , zinc, cadm i um , m a gnesium , and arsenic. Results from these sam p les were generally well below the applicable OSHA lim its. However, torch cutting and burning structural steel at the rubble pile resulted in instances of overexposures as follows: copper (17); iron oxide (28); lead (19); zinc oxide (1), antim ony (1); and cadm i um (3).

There were 236 sam p les collected for em ployee noise, and 20 sam p les exceeded the OSHA PEL of 90 dBA.

VI.a.2. NIOSH Data The NIOSH sam p ling occurred between Septem ber 18 and October 14, 2001. The focus was on search-and-rescue personnel, heavy equipm ent operators, and workers cutting m e tal beam s, but other occupations were also sam p led. A total of 1174 air sam p les were taken, including 804 for asbestos. The New York City Departm e nt of Health and Mental Hygiene (NCDOHMH) collected m o st of the asbestos sam p les, while NIOSH personnel collected all other sam p les. In addition to air sam p les, 33 sam p les of dust, debris, and other m a terials were taken. NIOSH has reported on results for asbestos , m e tals, respirable particulate, CO, hydrogen sulfide, inorganic acids, VOCs, elem ental carbon, Freon TM -22, and PAH (CDC, 2002).

The bulk sam p les m o stly showed asbestos concentrations at <1% (by m a ss); 3 of 29

sam p les had m a ss concentrations ranging from 1-3%. Analysis of air sam p les for asbestos by PCM revealed fibers in 358 of 804 sam p les (45%). Of 25 sam p les m easured by PCM which exceeded the 0.1 f/cc REL, 18 were m easured then by TEM, and all had asbestos concentrations less than 0.1 f/cc. Differential analysis by polarized light m i croscopy of these 25 air sam p les revealed that m o st nonasbestos fibers were fibrous glass, gypsum , and cellulose.

Air concentrations of total (36 sam p les) and respirable (18 sam p les) particles showed

m a xim u m concentrations of 2.3 and 0.3 m g /m 3 , respectively, which are below the corresponding RELs of 10 and 5 m g /m 3 f o r Portland cem ent. Respirable crystalline silica was not detected in any of the 18 sam p les m easured for it.

Two instantaneous peak CO m easurem ents exceeded the 1,200 ppm level (at 1239 and 1369 ppm ), the level NIOSH considers an im m e diate danger to life and health. One was from a

DRAFT--DO NOT QUOTE OR CITE 126 October 2002torch cutter and the other from a gasoline-powered saw operator. In 99 other sam p les, concentrations of CO ranged from 0.2 to 242.0 ppm

. This high value was from a 32 m i nute

sam p le, and it exceeded the NIOSH lim it of 200 ppm and would have exceeded the PEL of 50 ppm had it been sustained for 2 hours.

CDC (2002) contains descriptions of all other contam inants m easured. In general, nearly all sam p les were below relevant lim its. An “Editorial note” at the end of the article (CDC, 2002, p. 455) concludes that, “At the tim e of the NIOSH sam p ling, the am bient air did not appear to be contam inated with toxic substances from the building or their contents or with com bustion products to an extent that posed an occupational health hazard.”

V1.a.3. Occupational Exposure to PCBs and Dioxins These two classes of com pounds were m easured at Ground Zero (W TC Building 5

m onitor) and for several locations just off-site. It was judged that EPA’s 8-hour continuous air

m onitoring data on these two classes of com pounds was adequate to be evaluating worker exposures in Section IV. These evaluations are contained in Sections IV.c (PCBs) and IV.d (dioxins), and are summ a rized here.

For PCBs, the highest concentration m easured was 153 ng/m 3 , which was m easured at Ground Zero. All other m easurem ents were less than 100 ng/m 3 , with m o st at ND or within a typical urban range of 1-8 ng/m 3

. These are m u ch lower than the NIOSH REL at 1000 ng PCB/m 3 as an 8-hr tim e weighted average air concentration (NIOSH, 2002) and the OSHA PEL at 500,000 ng PCB/m 3 as an 8-hr tim e weighted average air concentration (NIOSH, 2002). Using EPA procedures for estim ating 95% upper bound cancer risk, an individual exposed to the highest concentration found at 153 ng PCB/m 3 for a period of one m onth is estim ated to have an

excess lifetim e cancer risk of about 2*10 -8

. EPA regulatory program s, such as the Superfund Program , typically consider individual increm ental cancer risk estim ates m a de in this m a nner (i.e., in the context of a scenario-based risk assessm ent) in the range of 10 -4 to 10 -6 to be of potential significance, depending on the circum stances. On this basis, an increm ental cancer risk estim ate in the range of 10 -8 is judged to be insignificant.

For dioxins, potential cancer and non-cancer risk were assessed using m e thods that are detailed in EPA’s Draft Dioxin Reassessm ent (EPA, 2000). First, a “scenario” is defined, which describes the pathways of exposures, contact rates with dioxin within these pathways, and the concentrations of dioxin in the exposure m e dia. The scenario for the Ground Zero worker was as follows: this individual is exposed 10 hours per day, 5 days per week, in the tim e period between Septem ber 12 until Novem b er 30, 2001. The pathway of exposure is via inhalation, and the rate of inhalation for a W T C worker is 1.3 m 3 /hr. Using data from the Ground Zero m onitor, the average concentration during this tim e was calculated as 60.7 pg TEQ/m 3

. Exposure during that tim e, expressed in term s of m a ss inhaled divided by body weight and tim e (pg TEQ/kg-day) is converted to a lifetim e dose, and when com b ined with the appropriate dioxin cancer slope, a 95% upper bound estim ate of cancer risk was estim ated as 3*10 -6 , which is about 2 orders of

m a gnitude lower (100 tim es lower) than current US background cancer risk to dioxin-like

com pounds. This background risk is prim arily due to ingestion of foods of anim al origin. For non-cancer risk, a newer approach based on calculation of an increm ental increase to background body burden was em ployed. The dose over the three m onth exposure period was used in a

DRAFT--DO NOT QUOTE OR CITE 127 October 2002sim p le m odel to predict body burden increase, and it was found that the exposure of the W T C workers suggests that their body burden could rise up to 10% above current average background. These cancer and non-cancer results resulting from dioxin exposure were evaluated as not significant risks over average background risks for this class of com pounds.

VI.b. D ata on Indoor Environments

EPA Region 2 is currently conducting extensive m onitoring and clean-ups of indoor residences. Much of the inform ation on this effort can be seen on the following website:www.epa.gov/wtc. Part of their effort is to also evaluate background conditions, so that

m easurem ents can be com p ared to this background. It is expected that this effort will provide data from which EPA can conduct further health risk assessm ents. Also, EPA’s Region 2 has been collecting data from various public and private m onitoring efforts, and have provided a tabular summ a ry of their prelim inary com p ilation for use in this report (table provided by M. Maddaloni, Region 2, to M. Lorber, EPA W a shington, August 18, 2002). The Agency for Toxic Substances and Disease Control (ATSDR) has conducted the only system atic study of the residential environm ent to date, and the results of their efforts are summ a rized below. Other

sum m a ries are provided below only for the system atic efforts that have been conducted or are underway.

VI.b.1. ATSDR Study on Apartments in Low er Manhattan The New York City Departm e nt of Hea lth and Mental Hygiene (NYCDOHMH) and ATSDR have released the Final Report of the Public Health Investigation to Assess Potential Exposures to Airborne and Settled Surface Dust in Residential Ares of Lower Manhattan (NYCDOHMH/ATSDR, 2002). From Novem b er 4 through Decem ber 11, 2001, environm ental

sam p les were collected in and around 30 residential buildings in lower Manhattan. In addition, four buildings above 59th Street were sam p led and used as a com p arison area for this investigation.

Bulk dust sam p les were collected both indoors and on outdoor surfaces and analyzed for the presence of asbestos by both the PLM (polar ized light m i croscopy) and TEM m e thods. PLM can distinguish between fiber types in a bulk sam p le by their unique appearance and color when viewed under different wavelengths of light. As bestos was detected in settled indoor dust in 10 out of 57 (18%) residential units sam p led, with the positive sam p les showing a m a xim u m of 1.5% asbestos in dust. By com p arison no asbestos was detectable in dust sam p les collected in the 5 com p arison residences. In outdoor dust collected at Lower Manhattan properties, asbestos was detected in 6 of 14 (43%) sam p les, with a m a xim u m asbestos concentration in dust of 3.4%.

Im portantly, airborne fibers were not det ected above background levels (stated as 0.003 f/cc -- fibers m eeting criteria for optical visibility) in any of the indoor air sam p les collected at the 57 residences in Lower Manhattan. Som e understanding of the protocol design is needed to interpret the air sam p ling data. All air f ilter sam p les were analyzed f i rst using PCM to determ ine if fibrous m a terials were present. If the PC M count (which does not distinguish fiber type) exceeded a 0.003 f/cc level identified as background (using the upper Manhattan m e asurem ents), then a TEM analysis for asbestos fibers was perform e d. Airborne asbestos fibers (m eeting equivalent criteria f o r optical visibility) were not detectable in any TEM analyses (generally <

DRAFT--DO NOT QUOTE OR CITE 128 October 2002.001 f/cc).

However, since only a m i nority of the sam p ling locations (6) had PCM counts above background, and hence were analyzed by TEM; results are not conclusive regarding the potential for low levels of airborne asbestos (i. e., atlevels < 0.003 f/cc -- fibers m eeting criteria for optical visibility). In this regard it should be noted that the specific residences that had detectable asbestos in indoor dust did not have elevated airborne PCM levels and TEM data were not collected for these residences. Note that when conditions allowed the residential sam p ling utilized an "aggressive" m e thodology involving the operation of the vacuum exhaust, used for settled dust sam p le collection, to stir the air. Additionally, evidence of elevated asbestos levels was not found in air sam p les collected in comm on areas of the apartm ent buildings or in adjoining outdoor areas.

The NYCDOHMH/ATSDR Final report also incl uded data on synthetic vitreous fibers (SVF or fibrous glass) concentrations in indoor and outdoor dust sam p les at the sam e residential locations. SVF (PLM analysis) was detected in a larger num ber of indoor dust sam p les (26 of 57 or 46%) and at higher concentrations (range 2-35%) than asbestos. In outdoor dust at these properties, SVF was detected in 11 of 14 (79%) of sam p les (concentration range 15 - 72%). As with asbestos, the study did not provide eviden ce of airborne SVF above background levels in indoor air sam p les collected at the residences in lower Manhattan. PCM m easurem ents will detect SVF, and in those locations where air sam p les had total PCM fibers exceeding background, Scanning Electron Microscopy (SEM) also reexam ined filters for SVF. W h ile such fibers were detectable in two sam p les, all sam p les were below 0.001 f/cc.

Air and settled surface dust sam p les were also analyzed for m i neral com ponents of concrete (quartz, calcite, and portlandite) and m i neral com ponent of building wallboard (gypsum , m i ca, and halite). The X-ray diffraction analysis (XRD) analysis for crystalline

m i nerals in air and settled surface dust is reported by NYCDOHMH/ATSDR as sem i quantitative (labeled with a “J”). Air sam p ling for m i nerals detected quartz and other building-related

m a terials in lower Manhattan. The other f o rm s of crystalline silica were not detected in any air

sam p les except f o r a one-tim e detection of cristobalite. The estim ated concentrations of these

m i nerals in air were low. In som e locations, m i neral com ponents of concrete (quartz [3-19 μg/m 3 J], calcite [ND-14 μg/m 3 J], and portlandite [ND-95 μg/m 3 J]) and m i neral com ponents of building wallboard (gypsum [4-15 μg/m 3 J] and m i ca [ND-43 μg/m 3 J]) were detected in air

sam p les at higher estim ated levels in lower Manhattan residential areas than in sam p les taken at

com p arison residential areas above 59th Street (quartz up to 6 μg/m 3 J, calcite up to 6 μg/m 3 J, portlandite up to 30 μg/m 3 J, gypsum up to 6 μg/m 3 J, and m i ca up to 17 μg/m 3 J). Quartz, calcite, portlandite and gypsum appear to m a ke up a higher percentage of dust in som e buildings in lower Manhattan when com p ared to settled surface dust sam p les from buildings above 59th Street. Quartz was detected up to an estim ated 31%J versus up to 2%J found in the com p arison areas above 59th Street. Neither cristobalite nor tridym ite was detected in any of the settled surface dust sam p les. Sim ilarly gypsum was found at a m a xim u m estim ated concentration of 30%J in settled surface dust, higher than the 4%J estim ated in the com p arison areas above 59th Street. Calcite and portlandite had m a xim u m c oncentrations of 21%J and 8%J respectively. At lower Manhattan locations sam p led, quartz was detected in 81% of comm on areas and 53% of residences. Gypsum was seen in 88% of com m on areas and 79% of residences. Minerals were

DRAFT--DO NOT QUOTE OR CITE 129 October 2002found in all lower Manhattan outdoor settled surface dust sam p les at estim ated values ranging as high as 27%J quartz, 19%J calcite, 5.5%J portlandite, and 27%J gypsum . No visible settled outdoor dust was available in the com p arison areas above 59th Street.

The NYCDOHMH/ATSDR investigators caution that the results of the NYCDOHMH/ATSDR investigation in Manhattan cannot be extrapolated to the lower Manhattan dwellings due to the lim ited num ber of units sam p led and lim ited ability to address different cleaning m e thods, distance from ground zero, or other confounding factors.

Som e of the key conclusions of the NYCDOHMH/ATSDR final report are:

· Exposure to significant am ounts of SVF, m i neral com ponents of concrete (quartz, calcite, and portlandite), and m i neral com ponents of building wallboard (gypsum ) m a y cause skin rashes, eye irritation, and upper respiratory irritation, all of which have been voiced as concerns by citizens and first responders. These irritant effects will subside once exposure to SVF, m i neral com ponents of concrete, and m i neral com ponents of building wallboard end. Som e people with pre-existing heart or lung disease (e.g., asthm a ) or a previous history of very high levels of exposures (occupational) to SVF,

m i neral com ponents of concrete, and m i neral com ponents m a y be m o re sensitive to the irritant effects of SVF, m i neral com ponents of concrete, and m i neral com ponents of building wallboard.

· Som e tim es m i neral com ponents of concrete (calcite and portlandite) and m i neral

com ponents of building wallboard (gypsum , m i ca, and halite) were detected in air

sam p les at higher estim ated levels in lower Manhattan residential areas than in sam p les taken at com p arison residential areas. These detected m i neral levels are orders of

m a gnitude below occupational standards. Although the occupational standards do not account for sensitive individuals or extended periods of exposure, they provide a

com p arison to an established health guidance value. The levels of m i nerals seen in airborne dust do not pose potential health hazards even for a continuous year of exposure at the highest levels detected.

· Som e settled surface dust could becom e airborne if disturbed. Therefore, people could potentially inhale the asbestos, SVF, m i neral com ponents of concrete (quartz, calcite, and portlandite), and m i neral com ponents of building wallboard (gypsum , m i ca, and halite) found in settled surface dust of som e lower Manhattan residences. Because the weight of dust present in the areas sam p led was not determ ined, it is not possible to determ ine whether any particular residence had an elevated dust loading. Appropriate continued frequent cleaning should m i nim i ze exposures.

· Several worst-case assum p tions were m a de in order to assess the potential long-term public health risks of airborne asbestos and quartz. Som e of the assum p tions were that no cleaning of indoor spaces has occurred or will occur, all fibers found in air were asbestos fibers, and the highest levels detected last fall in air represent long-term air levels. Using these worst-case assum p tions, prolonged exposure (decades) to airborne asbestos and quartz may increase the long-term , theoretical risk of people developing lung cancer and

DRAFT--DO NOT QUOTE OR CITE 130 October 2002other adverse lung health effects (m ore than 1 additional case in 10,000 people exposed). For individuals who conduct frequent cleaning of their residences, or participate in the EPA cleaning/sam p ling program (described below), it is unlikely that their exposure would resem b le these worst-case conditions. Residents who follow these cleaning

recomm e ndations would not be expected to have any significant increased risk of cancer or other long-term health effects due to asbestos or quartz.

Based upon the conclusions of their investigation, NYCDOHMH and ATSDR m a de the following recomm e ndations (NYCDOHMH/ATSDR, 2002):

· Because m o re asbestos, synthetic vitreous fibers (e.g., fiberglass), m i neral com ponents of concrete (quartz, calcite, and portlandite), and m i neral com ponents of building wallboard (gypsum , m i ca, and halite) were found in settled surface dust in lower Manhattan residential areas when com p ared to com p arison residential areas, the New York City Departm e nt of Health and Mental Hygiene and the Agency for Toxic Substances and Disease Registry are recom m e nding that people continue to conduct frequent cleaning with HEPA vacuum s and dam p cloths/m ops to reduce the potential for exposure.

· To ensure that the recomm e nded frequent cleaning is effective and to ensure that the health of the people of New York City is protected, the New York City Departm e nt of Health and Mental Hygiene and the Agency for Toxic Substances and Disease Registry

are recom m e nding additional m onitoring of residential areas in lower Manhattan. In addition, an investigation should be conducted to better define background levels specific to the city of New York for asbestos, synthetic vitreous fibers, m i neral com ponents of concrete (quartz, calcite, and portlandite), and m i neral com ponents of building wallboard (gypsum , m i ca, and halite).

· Lower Manhattan residents concerned about possible W o rld Trade Center-related dust in their residential areas can request cleaning and/or testing from the Environm ental Protection Agency as part of their current clean-up program (see next section).

VI.b.2. The Multi-Agency Task Force Efforts Led by US EPA EPA and its federal, state and city partners have begun to clean up residences im pacted by the collapse of the W o rld Trade Center. The clean-up covers residential units south and west of Canal, Allen and Pike Streets, river to ri ver. This effort is being coordinated by the

m

u lti-agency Task Force on Indoor Air in Lower Manhattan created by the EPA Adm i nistrator. Much of the inform ation on this clean up effort can be found on the web at http://www.epa.gov/wtc. The clean-up includes:

• upon request, the clean-up of residential units, using certified contractors, with followup testing for asbestos in the indoor air, or; testing-only of asbestos in the indoor air;

• r eim bursem e nt f o r HEPA (High Ef f i ciency Particulate Air) f ilter vacuum s;

• d istribution of health and cleanup inform ation;

DRAFT--DO NOT QUOTE OR CITE 131 October 2002• e stablishm ent of a W e b page (http://www.epa.gov/nyrdust2/dustcleanup/) and a toll-free hotline (1-877-796-5471 (TTY for the deaf and hard of hearing: 1-800-396-1018)) to take cleanup and testing requests;

• p rofessional cleanups of rem a ining unoccupied, uncleaned buildings;

• e valuation of effectiveness of dust cleanup techniques already used, and testing to establish what the pre-existing levels of contam inants were for Manhattan residences.

Three studies are underway to help develop this clean up plan:

Indoor Air Assessment: Selecting Contaminants of Potential Concern and Setting Health-Based Benchmarks - The Contam inants of Potential Con cern (COPC) Comm ittee of the W o rld Trade Center Indoor Air Task Force is preparing this report to select COPCs and set health-based benchm arks f o r levels in residences to assist the Pilot Cleaning Ef f ectiveness Initiative and inform the selection of contam inants in the Background Study (these latter two studies are addressed below). Six COPCs have been propos ed: lead, PAHs, dioxin, asbestos, fibrous glass and crystalline silica. For each COPC, benchm ark screening levels have been established for both indoor air and indoor surfaces, using a three tier approach:

• T ier I - Level above which, after elim ination of potential indoor sources (combustion byproducts, stored chem icals, etc.), aggressive clean-up action should be taken expeditiously along with follow-up sam p ling to confirm attainm e nt of Tier III level.

• T ier II - Range where diligent cleaning should continue, after elim ination of potential indoor sources (com bustion by-products, stored chem icals, etc.), with follow-up sam p ling to confirm attainm e nt of Tier III level.

• T ier III - Level below which the risk is negligible or consistent with the New York City background level found in the Background Study.

Pilot Cleaning Effectiveness Initiative - EPA is conducting a pilot program in an uncleaned/unoccupied building at 110 Liberty Str eet to determ ine the effectiveness of various cleaning m e thods for rem oving asbestos and other contam inants of potential concern from residential dwellings. EPA has com p leted sam p ling for contam inants in 110 Liberty Street, a still-unoccupied building close to the W T C site, in what is a com p rehensive test of the effectiveness of various cleanup techniques. Cleani ng procedures to be tested include those that

were recomm e nded following the collapse of the W T C as well as others that m a y have been used in cleaning residential units. Com p rehensive sam p ling has been or will be conducted before, during and after the pilot cleanup.

Background Study - Most if not all of the pollutants associated with the collapse of the W o rld Trade Center were present in New York City' s environm ent prior to Septem ber 11. To establish a baseline f o r the presence of these contam inants in af f ected residences, EPA will collect and analyze sam p les to look for som e of these pollutants in apartm ents in parts of Manhattan that were not im pacted. The Agency will use the data to determ ine pre-existing or "background" levels of these pollutants in interior spaces in New York City.

DRAFT--DO NOT QUOTE OR CITE 132 October 2002VI.b.3. Ground Z ero Elected Offici als Task Force Study of Apartments A “Ground Zero” Elected Officials Task Force convened within days of Septem ber 11 to evaluate the environm ental safety of apartm ents that housed an approxim a te population of 50,000 residents of lower Manhattan who lived within blocks of Ground Zero. A sm all-scale

m onitoring study of two residential buildings was conducted by contract (Chatfield and Kom i nsky, 2001). Surface wipe sam p les were taken from both exposure residential dwellings characterized as “high” and “low”. The “high” location, so nam e d due to the expectation that higher concentrations would be m easured, was in an apartm ent building located on South End Avenue, close to and southwest of Ground Zero. Apartm ent 10D, on the East side of this building and which had sustained window dam a ge, was selected for sam p ling. Heavy dust deposits were in the apartm ent and were sam p led for this study. The “low” location was located four blocks north on W a rren Street. The apar tm ent building did not appear to sustain any external dam a ge. Apartm ents on the 2 nd and 5 thfloor were sam p led. Dioxins, furans, and PCBs

were m easured in wipe and bulk dust sam p les. Inorganic m e tals including arsenic, cadm i um , m e rcury, lead, and several others, were m easured. Asbestos in air and dust was also m easured in all sites.

Concentrations of dioxin, PCBs and m e tals were generally within “background” levels for both the “high” and “low” exposure apartm ents. However, asbestos readings were elevated in both air and dust, particularly in the “high” apartm ent. Chrysolite asbestos fiber counts were obtained using TEM analysis and AHERA coun ting protocols (fibers > .5 μm ) and also by PCME (fibers >5 μm ). Looking at the TEM analysis using AHERA protocols for this summ a ry, 7 air sam p les in the “low” site showed 6 indoor exceedences of the 70 S/m m 2 AHERA standard at 316, 379, 279, 142, 141, and 162, with the last sam p le being a rooftop sam p le showing a reading of 6.5 S/m m 2

. All these sam p les were obtained at volum es very near the required 1200 liters. The “high” air sam p les were extrem ely elevated with asbestos, and m o st sam p lers were discontinued before 1200 liters due to high dust on the filter. Counting of structures greater than 0.5 μm was stopped after just one grid opening because of the large num ber of structures to count. The six m easurem ents equal 10,620; 7,832; 6,277; 6.285; 7,155; and 548 S/m m 2

. The last sam p le listed here was an exterior sam p le; it was taken from just outside a sliding window in the apartm ent.

Asbestos in indoor dust sam p les was sim ilarly very high. At the “low” apartm ent, dust was visible on all surfaces and wipe sam p les were taken with a wet non-woven cloth in accordance with ASTM D6480-99. At the “high” apartm ent, furniture and surfaces were coated with a thick coat of dust that could be swept up with a brush. A new toothbrush was used to collect sam p les in this apartm ent. At the low apartm ent, surface chrysotile concentrations up to 470,000 S/cm 2 were observed, of which up to 79,000 fibers/cm 2 were fibers and bundles longer than 5 μm

. In the high apartm ent, surface chrysotile concentrations of up to 990,000 S/cm 2 were observed, of which up to 46,000 were fibers and bundles longer than 5 μm

.
Outdoor dust sam p les and the percentage chrysotile by weight included: a sam p le collected on the roof of an autom obile parked on Church St on the North side of the W T C site - 0.67% chrysotile, on top of an apartm ent house on W a rren St - 1.05% chrysotile, and two

sam p les on the southwest side of the W T C site on South End Ave - 2.25% and 2.05% chrysotile.

DRAFT--DO NOT QUOTE OR CITE 133 October 2002VI.b.4. NewYork City Department of Environmental Protection Sampling of Indoor Dust and Air The New York City Departm e nt of Envir onm ental Protection (NYCDEP) has gathered indoor dust and air sam p ling data from num erous building owners/m anagers as part of their Asbestos Control Program

. Sam p ling procedures and analytical m e thods vary from building to building m a king data summ a ry dif f i cult. For settled dust, bulk sam p les were generally obtained and analyzed for percent asbestos content. Many buildings report pending results. Available data indicate non-detect or trace am ounts of asbestos in m o st locations. In general, asbestos concentrations were low especially when com p ared with occupational standards. Most sam p le analyzed by PCM (NIOSH 7400) were below 0.01 f/cc while m o st sam p les analyzed by TEM (AHERA) were below 70 S/mm 2

.

VI.b.5. NewYork City Board of Education Sampling of Schools At the request of the Board of Education (BOE), ATC Inc. conducted bulk dust/wipe and indoor air sam p ling during the tim e period Decem ber 2001 to March 2002 in the following W T C area schools: Stuyvesant HS (345 Cham bers St ), HS of Econom ics and Finance (100 Trinity Place), HS for Leadership and Public Service (90 Trinity Place), PS 150 (334 Greenwich St), PS 234 (292 Greenwich St), and PS/IS 189 (201 W a rren St). A lim ited am ount of asbestos bulk dust sam p les were obtained from these schools. No sam p les taken from inside the schools exceed 1% asbestos. One sam p le from PS/IS 189 taken from outside the building exceed 1% asbestos and one sam p le taken from debris on the roof of PS 234 exceeded 1% asbestos. W i pe sam p les were obtained and analyzed for a host of contam inants including lead, chrom i um , cyanide, PCBs, dioxin, silica and fibrous glass. W ith few exceptions, levels were below health-based guidelines/standards. Exceptions included: P S 150 had one lead sam p le from a window well that exceeded HUD guidelines; HS of Econom ics and Finance had m u ltiple lead wipes that exceeded HUD guidelines; Stuyvesant HS had lead sam p les from the 5 thand 6 thfloor that exceeded 40 μg/ft 2 on 02/06/02, but follow-up sam p ling the next day were below HUD guidelines.

All six schools were repeatedly sam p led (sam ples from Stuyvesant began on 9/21/01) for asbestos in air by AHERA TEM protocols. All sam p les were below the AHERA standard of 70 S/m m 2 with the following exceptions: HS for Leadership and Public Service - (2/23/02) 956 S/mm 2 found in the 2 nd floor auditorium ; (2/24/02) 2,379 S/m m 2 found in the basem e nt gym ; (2/26/02) 978 S/mm 2 found in the basem e nt gym

. Two follow-up sam p les taken from the gym on 2/28/02 were non detect.

All six schools were repeatedly sam p led for respirable particulates (PM 2.5 ). Most schools had m u ltiple days that exceeded the 24 hr standard for sensitive subpopulations (40 μg/m 3 ) but few exceeded the 24 hour standard of 65 μg/m 3

.

DRAFT--DO NOT QUOTE OR CITE 134 October 2002

### Section VII. Comments and Future Studies

Am bient concentrations of m onitored substances of concern have generally decreased to background concentrations in the afterm ath of the Septem ber 11 disaster. Most substances were at these backgrounds during 2002, although som e exceptions were noted. Concentrations of benzene and other VOCs at the North Tower site were considerably above typical urban background as recently as early January, and air concentrations of dioxin were considerably elevated above urban background at m onitors close to the W T C site through early Decem ber. The average daily benzene concentration at the North Tower was also above the OSHA PEL in early January. Concentrations of asbestos above the AHERA standard were detected in February and March.

Although the general trend of decreasing am bient concentrations for the m easured pollutants is reassuring, there are lim itations in the interpretation of the data. For exam ple, very little data are available for exposures in the few days to a week imm e diately after Septem ber 11, and there is very little inform ation on exposures inside residences or offices where people spend

m o st of their tim e. Sam p ling of air and dust within residences has been conducted by ATSDR, and the results of that study are provided. This study showed very little asbestos in the air in apartm ents near the W T C and in the com p arison apartm ents. However, a sm all num ber of apartm ents near the W T C had asbetsos detected in the dust sam p les while none were detected in the com p arison apartm ents. Air and dust within 2 apartm ents located near the W T C were

sam p led on Septem ber 18. Very low concentrations of dioxin, PCBs and m e tals were found. However, asbestos readings were elevated in both air and dust in both apartm ents. EPA is now conducting extensive indoor air m onitoring, and the results will be evaluated in future EPA reports.

Data do exist for reactive VOCs such as form aldehyde, acetaldehyde, or acrolein, all of which are irritants and m i ght have been produced by the fires at W T C, but to date, these data have not been evaluated. Although the press reported the fires to be out at the W T C site on Decem ber 20, there are reports that the fires flared up on occasion in January.

From interpretation of photographs taken during the hours following the collapse of the W T C Towers, it is speculated that som e people m a y have been exposed to the extrem ely high levels of am bient PM and its constituents were likely to be at risk f o r im m e diate acute respiratory and other sym p tom s

. Fine particles or m e tals such as chrom i um and nickel in the initial dust cloud could have been irritating or sensitized individuals to further response. The

cum u lative risk from so m a ny different exposures at high concentrations m a y well have produced effects that cannot be fully discer ned by exam ination of exposure to individual substances. The potential f o r m u ltiple chem ical sensitivities is of potential concern. Also, even though data m a y suggest that a substance is associated with a particular effect, a quantitative guidance value m a y not have been developed. Thus, sim p ly com p aring am bient concentrations against known health guidance values m a y overlook som e effects.

Further studies of potential health effects resulting from the W T C disaster are being conducted by a variety of agencies and institutions. These should help in evaluating som e of the

rem a ining uncertainties regarding exposure and hum an health im pacts resulting from the

DRAFT--DO NOT QUOTE OR CITE 135 October 2002collapse of the W T C buildings. Results from som e of these studies are not expected for several years, although som e results should be available earlier. Studies are being conducted to evaluate exposures and health effects in persons that were around Ground Zero on Septem ber 11 and throughout the rescue and cleanup operations. The studies will be extrem ely im portant in getting

a m o re com p lete picture of som e of the actual health effects that resulted from exposures. This is particularly im portant because we have very little data regarding what people were exposed to Septem ber 11 as they were leaving the W T C area surrounded by plum es of dust and burning debris.

To better understand actual exposures on Septem ber 11, researchers at EPA’s ORD laboratories, in cooperation with academ ic institutions, are working on projects that will use

com puter m odels to reconstruct the plum e of dust and debris. The goal is to m odel and predict the levels of contam inants that were present in the air im m e diately f o llowing the collapse of the W T C buildings. Prelim inary results from that m odeling have been presented in this report. Investigators are using m e teorological data and data available from m onitoring results later in Septem ber to estim ate exposures. W h en this research is com p lete, it will aid in addressing health effects.

Studies are also being conducted to help us better understand how exposure to contam inants m easured and collected in lower Manhattan throughout this period m a y cause adverse effects in laboratory tests and anim al m odels. As cited previously, ORD NHEERL scientists conducted several studies to exam ine the chem ical and toxicological properties of PM 2.5 derived from bulk settled W T C dust (EPA, 2002c; McGee et al., 2002). Com p arative respiratory toxicology studies showed that a high dose of W T C PM 2.5 caused m ild lung inflamm a tion and significant respiratory tract hyperresponsiveness in m i ce. Am bient concentrations which could cause com p arable doses and effects in people are high but conceivable (425 μg/m 3 over 8 hours) in the imm e diate afterm ath of the collapse of the towers (Gavett et al., 2002). Dust and air sam p les are also being evaluated by other researchers through funding from NYSDOH.

Most im portantly, m a ny local, state and federal agencies and academ ic institutions have already began or are planning studies that will m onitor the health status of various groups of people that were affected by the events of Septem ber 11. In total, EPA is aware of m o re that 120 studies on health effects in populations im pacted by the events of Septem ber 11. Although it is im possible to address them all, a few general categories are discussed below.

• H ealth status, including asthm a , am ong students is one of the m a ny health endpoints that will be evaluated at m a ny schools. Respiratory sym p tom s , including asthm a , will be studied in pre-school children and other child populations as well.

• L ongitudinal cohort studies on the im pacts on pregnant wom e n and birth outcom e s are also being conducted.

DRAFT--DO NOT QUOTE OR CITE 136 October 2002• C ohort studies looking at m u ltiple health endpoints are beginning to evaluate health effects in populations of workers involved in the rescue and cleanup effort s.

• S tudies are under way to investigate m a ny different m e ntal health outcom e s including post-traum a tic stress disorder, traum ato children, behavioral changes in adolescents, changes in therapy adherence in HIV/AIDs patients, im pacts in particular NYC m i nority populations, and im pacts in occupational groups involved in the cleanup and rescue efforts.

• While m onitoring air quality is com p lete at the W T C site, NYSDEC will continue its routine am bient air m onitoring at a num ber of nearby sites and at the sites around New York City, including a num ber of schools.

It is hoped that when they are com p leted, these studies will provide a m o re com p lete picture of actual health outcom e s. This current report can only evaluate exposures based upon available m onitoring data and results, and what these exposures could m ean to hum an health. Wh en the health studies are com p leted, it will be very usef ul f o r EPA to go back and reassess how well the evaluations in this report identif ied, or didn’t identify, a hum an health concern. This retrospective look will help EPA and other health agencies to do a better job assessing health risks and outcom e s in the f u ture. In the m eantim e, EPA will continue to address potential health risks as needed. EPA will provide a m o re thorough report, looking at additional contam inants and conducting further evaluations as needed.

DRAFT--DO NOT QUOTE OR CITE 137 October 2002

### Section VIII. References

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US EPA (1986c) Airborne asbestos health a ssessm ent update. United States Environm ental Protection Agency, Office of Health and E nvironm ental Assessm ent. EPA/600/8-84/003F.

US EPA. (1984) Risk Analysis of TCDD Contam inated Soil. U.S. Environm ental Protection Agency, Office of Health and Environm ental Assessm ent. EPA-600/8-84-031.

US EPA. (1982) Air quality criteria for particulat e m a tter and sulfur oxides. Research Triangle Park, NC: Office of Health and Environm en tal Assessm ent, Environm ental Criteria and Assessm ent Office; EPA report no. EPA-600/ 8-82-029aF-cF. 3v. Available from : NTIS, Springfield, VA; PB84-156777.

USGS. 2002. U. S. Geological Survey Open File Report OFR-01-0429. Environm ental Studies of the W o rld Trade Center area after the Septem ber 11, 2001 attack. Denver, CO: U. S. Geological Survey. Available: http://geology.cr.usgs.gov/pub/open-file-reports/ofr-01-0429/ [accessed 6 July 2002].

DRAFT--DO NOT QUOTE OR CITE 142 October 2002Van den Berg ML, Birnbaum L, Bosveld ATC, Brunstrom B, Cook P, Feeley M, Giesy JP, Hanberg A, Hasegawa R, Kennedy SW
, Kubiak T, Larsen JC, van Leeuwen FXR, Liem AKD, Nolt C, Peterson RE, Poellinger L, Safe S, Schrenk D, Tillitt D, Tysklind M, Younes M, W a rn F, Zacharewski T. Toxic Equivalency Factors (TEFs) for PCBs, PCDDs, PCDFs for Hum a ns and W ildlife. Environm ental Health Perspectives, 1998; 106: 775.

Vette, A.; Landis, M.; W illiam s , R.; W e bb, L.; Ellestad, T.; Vallero, D. (2002) Concentrations and com position of PM at Ground Zero and lower Manhattan after Septem ber 11, 2001. In preparation.

W a lker Y, Lorber M, W a ng V, Gillooly P. 2002. Im pacts of dioxin em issions from the Shinkapo Incinerator to the United States Naval Air Facility at Atsugi, Japan. Part 2: Air im pacts. Organohalogen Com pounds 56:481-484.

W HO 1998. Chrysotile asbestos: Environm ental Health Criteria. Geneva: Switzerland: W o rld Health Organization.

DRAFT--DO NOT QUOTE OR CITE 143 October 2002APPENDIX A - WORLD TRADE CENTER HEALTH EFFECTS SCREENING CRITERIA FOR AMBIENT AIR DEVELOPED BY EPA’S REGION 2

Provided by: M ark Maddaloni US EPA, Region 2

DRAFT--DO NOT QUOTE OR CITE A-1 October 2002World Trade Center Health Effects Screening Criteria for Ambient Air

Introduction

Extensive air quality m onitoring data have been collected at and around the W o rld Trade Center (W TC) site since 9/11/01. Table 1 (Screening Criteria) is intended to provide health protective screening values for data evaluation. Analysis has been perform e d on an extensive list of potentially W T C-related contam inants. Many of the chem icals screened have dem onstrated a consistently low (i.e., below detection lim its or trace am ounts) trend. Consequently, the list of contam inants in Table 1 represents those chem icals that, because of their intrinsic toxicity and frequency/m a gnitude-of -detection, pose the greatest potential hazard from exposure. This selection process (i.e., a toxicity/concentration analysis), although qualitative, reflects the contam inant-of-concern identification proce ss recom m e nded in the Risk Assessm ent Guidance for Superfund. Table 1 m a y be expanded as additional data analysis becom e s available. Two populations have been identified for assessm ent: response/dem o lition (i.e., W T C site) workers; and residents living in Lower Manhattan (e.g., Battery Park City, Tribeca and other residential locations close to Ground Zero). Included in the resident category are all other workers located in Lower Manhattan with the exception of W T C site workers.

Relevant Standards

The following paradigm has been em ployed to develop screening values. For each of the two identified receptor populations (i.e., site workers and residents), existing standards are utilized where appropriate. Occupational standards (i.e., OSHA PELs) are used for all site workers conducting response/dem o lition activities covered by OSHA. Monitoring data from dem o lition

areas are com p ared to OSHA PELs. (For exam ple, the OSHA PEL of 1 ppm for benzene is used to evaluate benzene air sam p les taken directly from within the plum e on the debris pile.) Environm ental standards (e.g., NAAQS, AHERA) are utilized to evaluate m onitoring data from the site perim e ter and beyond where residents or non-W T C site workers m a y be exposed. (For

exam ple, lead air m onitoring data from perim e ter stations outside of the imm e diate work zone are evaluated against the NAAQS of 1.5 μg/m 3 ).

Risk-Based Screening Criteria

In cases where appropriate standards do not exist, risk-based screening criteria have been developed for residential (including the non-W T C site workers) receptors. (In the absence of OSHA standards, it is beyond the scope of EPA’s m i ssion to develop “occupational” screening values.) The risk assessm ent paradigm detailed in EPA’s “Hazard Evaluation Handbook: A Guide to Rem oval Actions” (HEH) was em ployed f o r this initiative (except where otherwise noted in the Table 1 footnotes). Screening levels reflect the m o st current toxicity criteria (Slope Factors and RfCs) on EPA’s IRIS database.

For carcinogenic com pounds excess lifetim e cancer risk was set at E-04 (one-in-ten thousand). The residential exposure scenario in the HEH was m odified for carcinogens from the default of 30 years (upper-bound estim ate for residency in one dwelling) to 1 year (to reflect an upper bound estim ate for the length of tim e a resident m a y be potentially exposed to W T C-related

DRAFT--DO NOT QUOTE OR CITE A-2 October 2002contam inants). In cases where the screening value based on a noncancer endpoint is m o re stringent, screening values for both cancer and noncancer endpoints are presented. It is also noted that the default 30 year exposure duration (and the 1 year site-specific adjustm e nt) reflects an apportionm ent between child (20% of total exposure duration) and adult (80 % of total exposure duration) receptors. Because children have com p aratively greater (as a function of body weight) respiration rates than adults, the screening values presented in Table 1 are

m a rginally m o re stringent than values that would otherwise be derived by direct application of IRIS verified Unit Risk values.

For noncarcinogenic com pounds, the Hazard Quotient (chronic daily intake/RfC) was set at 10. A Hazard Quotient of 10 is em ployed in the HEH to account for the fact that chronic toxicity criteria (RfDs/RfCs) are being applied to sub-chr onic exposure scenarios that are not expected to exceed 6 m onths - 1 year in duration. Accordingly, a Hazard Quotient of 10 was utilized for non-carcinogens in Table 1 to reflect a sim ilar (i .e., upper bound of 1 year) exposure duration. It is noted that contam inants (both non-carcinogens and carcinogens, alike) can exhibit acute effects from short-term , high-dose exposures. Because the screening values in Table 1 are based on subchronic exposure (i.e., 1 year), acute effects from exposures that are below the screening levels would be unlikely. Additionally, a revi ew of California EPA’s (CAL-EPA) Acute Risk Levels dem onstrates that the screening criteria in Table 1 are categorically m o re stringent than the Cal-EPA’s analogous acute levels.

NOTE: Individual sam p ling results that exceed screening values should not be interpreted to represent the occurrence of an adverse health effect. Rather, such inform ation indicates the need for careful m onitoring and the assessm ent of longer-term data trends for evaluation against appropriate health criteria. That is, m o st of the screening levels have been developed to account for continuous one year average exposure durations. Because these screening levels assum e continuous exposure for an extended duration, the average of the m easured concentrations is

m o re appropriate for evaluating risk than an individual m easurem ent. Consequently,

m i scellaneous individual values above the screening level m a y not necessarily be indicative of potential for concern.

Table 1 World Trade Center Screening Criteria
Contaminant Site Worker (1) Resident (2)
Inorganics

Asbestos (3) .1 f/cc (PCM) 70 S/m m 2 (TEM)

Cadm ium 5 μg/m 3 .2 μg/m 3 (9) 3 μg/m 3 (5)

Chrom i um (4) 100 μg/m 3 .6 μg/m 3 (5)

Lead 50 μg/m 3 1.5 μg/m 3 (7)
Manganese 5 m g /m 3 .5 μg/m 3 (6)

DRAFT--DO NOT QUOTE OR CITE A-3 October 2002Contaminant Site Worker (1) Resident (2)

Sulfur Dioxide 5 ppm .14 ppm (7)

Particulates

Total 15,000 μg/m 3 NA Respirable 5,000 μg/m 3 NA

PM 2.5 NA 40 μg/m 3 (8) 65 μg/m 3 (7)

PM 10 NA 150 μg/m 3 (7,8)

Sem i volatiles Dioxin/Furans (TEQ) N A .162 ng/m 3 (5)

PCBs 1,000 μg/m 3 .73 μg/m 3 (6) 9 μg/m 3 (5)

PAHs (16) NA 6 μg/m 3 (5, 17)

Volatiles

Acetone 1,000 ppm 1.5 ppm (6)
Benzaldehyde NA 860 ppm

Benzene 1 ppm .02 ppm (9) .21 ppm (5)

Benzonitrile NA NA
1,3 Butadiene 1 ppm .01 ppm (5, 15)

Chlorom e thane 100 ppm .4 ppm (6) 2.6 ppm (5)
1,4 Dioxane 100 ppm .5 ppm (5)

Ethanol 1,000 ppm 45 ppm (10)
Ethylbenzene 100 ppm 2.5 ppm (6)

Freon 22 1,000 ppm (14) 140 ppm Propylene LEL (13) sim p le asphyxiant
Styrene 100 ppm 2.3 ppm (6)
alpha m e thylstyrene 100 ppm .1 ppm (6)

DRAFT--DO NOT QUOTE OR CITE A-4 October 2002Contaminant Site Worker (1) Resident (2)
Tetrahydrofuran 200 ppm .9 ppm (5)

Toluene 200 ppm 1.1 ppm (6)
Xylenes 100 ppm 1 ppm (11)

Reactive Gases Acetaldehyde 200 ppm .05 ppm (6) 1.3 ppm (5)

Form aldehyde .75 ppm .04 ppm (12) .35 ppm (5)

Acrolein .1 ppm .0001 ppm (6)

Units

f/cc = fibers (>5 μm length) per cubic centim eter of air S/m m 2 = structures (>.5 μm length) per square m illim eter of f

ilter paper ppm = parts per m illion in air μg/m 3 = m i crogram s of contam inant per cubic m e ter of air ng/m 3 = nanogram s of contam inant per cubic m e ter of air NA - Not Applicable

Footnotes:

1. “Site W o rkers” refers to all workers involved in the response/dem o lition of the W o rld Trade Center. Listed values are Occupational Safety and Health Adm i nistration (OSHA) Perm issible Exposure Lim its (PELs), Tim e W e ighted Averages (TW A ) unless otherwise noted.

2. “Residents” refers to people living in the vicinity of the W o rld Trade Center as well as all other potentially exposed workers not involved in the response/dem o lition

3. Resident screening value is based on Asbe stos Hazard Em ergency Response Act (AHERA)

m e thodology which uses transm ission electron m i croscopy (TEM), and because of its basis in “background” (vs a risk basis) includes all asbestos fibers greater than 0.5 m i crons in length. W o rker values are based on phase contrast m i croscopy (PCM, - which doesn’t distinguish asbestos from other fibers) or, for results above the PCM screening value, TEM to derive a PCM equivalence that includes all asbestos fibers greater than 5 m i crons in length.

4. Screening values for chrom i um were based on the m o st toxic form (hexavalent)

5. EPA - Hazard Evaluation Handbook (HEH) (car cinogen) > 1 year of continuous exposure equating to an excess lifetim e cancer risk of one-in ten thousand

DRAFT--DO NOT QUOTE OR CITE A-5 October 20026. EPA - HEH (noncarcinogen) > Hazard Quotient (HQ) = 10

7. National Am bient Air Quality Standard (NAAQS) - Lead is a 3 m onth average - PM 2.5 is a 24 hour average - Sulfur Dioxide is a 24 hour average prim ary standard

8. Air Quality Index (AQI)

9. Non cancer effects based on CAL-EPA toxicity studies

10. Am erican Conference of Governm e ntal Indus trial Hygienists (ACGIH) Threshold Lim i t Value (TLV)

11. Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation m i nim u m risk level (MRL) x 10

12. ATSDR acute MRL

13. Lower Explosive Lim it (2 - 11 %)

14. National Institute of Occupational Safety and Health (NIOSH)

15. Proposed Reference Concentration (RfC) - HEH (noncancer) > Hazard Quotient (HQ) = 10

16. Based on Benzo(a)pyrene toxicity equivalenc y factor toxicity equivalency factor (TEF)

17. EPA National Center for Environm ental A ssessm ent (NCEA) provisional inhalation Slope Factor (3.1 E 00 m g /kg/day -1 )

DRAFT--DO NOT QUOTE OR CITE A-6 October 2002APPENDIX B - TABLE OF MONITORING LOCATIONS

DRAFT--DO NOT QUOTE OR CITE B-1 October 2002Table 1.Overview of monitoring locations and responsible parties (see note at end of table for specific notes).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryI.EPA’s Environmental Response TeamLettered SitesLocation ABarclay St & WestBroadwayAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekParticulates, VOCs24 hr. sample daily; grab (VOC)EPA/ORDLocation BChurch St and Dey StAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekLocation CLiberty St and TrinityStAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekParticulates, VOCs24 hr. sample daily; grab (VOC)EPA/ORDLocation C1(note:station Cand C1are“alternate”stations; seefootnote 1)Broadway and LibertyStAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekParticulates24 hr. sample every 3rd dayEPA/ORDLocation DAlbany St &Greenwich StAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekLocation ELiberty St & South EndAveAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekDRAFT--DO NOT QUOTE OR CITEB-2October 2002B-3

DRAFT--DO NOT QUOTE OR CITE October 2002 Table 1. Overview of monitoring locations and responsible parties (cont’d).

Site Name Site Location Pollutants Measured Sampling Frequency Analytical Laboratory

I. EPA’s Environmental Response Team Lettered Sites (cont’d).

Location F Vesey St & West St Asbestos 2 - 12 hour samples daily Contract Dioxins (2)/PCBs, Metals 8 hour sample twice per week Location G Church & Duane St Asbestos 2 - 12 hour samples daily Contract Location H Chase Manhattan Plaza Asbestos 2 - 12 hour samples daily Contract Location I Broadway & Wall St Asbestos 2 - 12 hour samples daily Contract Location J Warren & West St Asbestos 2 - 12 hour samples daily Contract Location K Albany & West St Asbestos 2 - 12 hour samples daily Contract Particulates, VOCs 24 hr. sample daily; grab (VOC) ORD Metals, Silica 8 hour sample twice per week Contract Location L North Side of

Stuyvesant High Total particulates ~ 8 hours/day Onsite Dataram Asbestos 2 - 12 hour samples daily Contract Metals, Silica 8 hour sample twice per week Contract Location M Harrison St & West St Total particulates ~ 8 hours/day Onsite Dataram Asbestos 2 - 12 hour samples daily Contract Location N Pier 25, Southside Total particulates ~ 8 hours/day Onsite Dataram Asbestos 2 - 12 hour samples daily Contract Location P Albany St & South End

Ave Asbestos 2 - 12 hour samples daily Contract

Dioxins (2)/PCBs, PAHs Metals, Silica 8 hour sample twice per week

Location Q Barclay St & West St Asbestos 2 - 12 hour samples daily Contract Location R EPA Taga Bus Total particulates ~ 8 hours/day Onsite Dataram Dioxins (2)/PCBs, PAHs Metals, Silica 8 hour sample twice per week ContractTable 1.Overview of monitoring locations and responsible parties (cont’d).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryI.EPA’s Environmental Response TeamLettered Sites (cont’d).Location SRector Pl & South EndAveAsbestos2 - 12 hour samples dailyContractDioxins (2)/PCBs, PAHsMetals, Silica8 hour sample twice per weekLocation TPier 6 HeliportAsbestos2- 12 hour samples dailyContractLocation UPier 6, Exit 2Asbestos2- 12 hour samples dailyContractLocation VPier 6, Bus SignAsbestos2 - 12 hour samples dailyContractLocation WWash Tent, West Street& MurrayAsbestos2 - 12 hour samples dailyContractWTC-Building 5SWAKA, Location 3ADioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekContractWTC-Church &Vesey(alternatefor WTC; seefootnote 1)AKA, Location 3BDioxins (2)/PCBs, PAHs,Metals, Silica8 hour sample twice per weekContractS.I. LandfillSites17 Landfill Sites + 3offsite locationsAsbestos1 - 12 hour sample dailyContract5 Landfill SitesTotal particulates12 hour sample daily when temp.& humidity specs are met.Onsite Dataram2 Landfill Sites + 3Offsite LocationsMetals1 - 12 hour sample weeklyContractDRAFT--DO NOT QUOTE OR CITEB-4October 2002Table 1.Overview of monitoring locations and responsible parties (cont’d).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryII.Extended Monitoring Network- NYSDEC Numbered Air Monitoring Stations1Park Row & SpruceStreet, NY, NYAsbestos12 hour sample dailyContractDioxin (1)72 hour sample every 3 daysRegion 7VOC's24 hr. sample every 3rd dayORDAldehydes24 hr. sample every 3rd dayNYSDOHPM Speciation24 hr. sample every 3rd dayContractPM Sizingcontinuous-by NYSDECClimetPM10, PM2.5continuous- by NYSDECPM 2.5 TEOM/PM10 Filter2Chambers St.& WestSt.,NY, NYAsbestos12 hour sample dailyContractDioxin (1)72 hour sample every 3 daysRegion 7VOC's24 hr. sample every 3rd dayORDAldehydes24 hr. sample every 3rd dayNYSDOHPM Speciation24 hr. sample every 3rd dayContractPM Sizingcontinuous-by NYSDECClimetPM10,PM2.5,PMcontinuous- by NYSDECPM 2.5 TEOM/PM10 Filter3U.S. Coast Guard,1 South Street,NY, NY (Battery Pk)Asbestos12 hour sample dailyContractPM10, PM2.5continuous- by NYSDECPM 2.5 / PM10 FilterDRAFT--DO NOT QUOTE OR CITEB-5October 2002Table 1.Overview of monitoring locations and responsible parties (cont’d).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryII.Extended Monitoring Network- NYSDEC Numbered Air Monitoring Stations (cont’d)4Canal Street PostOffice, 350 CanalStreet, NY NYAsbestos12 hour sample dailyContractPM10, PM2.524 hour sample dailyby NYSDECPM 2.5 / PM10 Filter5PS 154, 333 East 35thStreet, Bronx, NY10454PM2.5continuous-by NYSDECPM 2.5 TEOMAsbestos12 hour sample dailyContract6IS 143, 511 West182nd StreetNY, NY 10033PM2.5continuous-by NYSDECPM 2.5 TEOMAsbestos12 hour sample dailyContract7PS 274, 800 BushwickAve, Brooklyn, NY11221PM2.5continuous-by NYSDECPM 2.5 TEOM /PM10 FilterAsbestos12 hour sample dailyContract8PS 44, 80 MapleParkway, Staten Island,NY 10303PM2.5continuous-by NYSDECPM 2.5 TEOMAsbestos12 hour sample dailyContract9PS 199, 39-20 48thAve, Long Island City,NY 11104PM2.5continuous-by NYSDECPM 2.5 TEOMAsbestos12 hour sample dailyContractDRAFT--DO NOT QUOTE OR CITEB-6October 2002Table 1.Overview of monitoring locations and responsible parties (cont’d).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryIII.Extended Monitoring Network- NJDEP Air Monitoring StationsNJ-ShellWest Avenue, Sewaren,NJAsbestos1 - 12 hour sample on Mon. andThurs.ContractNJ-CitgoTremly Point Road,Linden, NJAsbestos1 - 12 hour sample on Mon. andThurs.ContractNJ-FMCRoosevelt Blvd.,Cartaret, NJAsbestos1 - 12 hour sample on Mon. andThurs.ContractNJ-LibertyLiberty State Park, @WTC Disaster FamilyCenterAsbestos1 - 12 hour sample on Mon. andThurs.ContractIV.Extended Monitoring Network- EPA/ORD Numbered Air Monitoring Stations14Albany & West StNY, NYDioxin (1)72 hour sample every 3rd daysRegion 7PM Speciation24 hr. sample every 3rd dayContractPM Sizingcontinuous-by NYSDECClimetPM10, PM2.5continuous-by NYSDECPM 2.5 TEOM/PM10 FilterVOCs24 hr sample every 3rd dayORD1523 Wall Street, NY,NYPM10, PM2.5continuous-by NYSDECPM 2.5 TEOM/PM10 FilterAldehydes24 hr. sample every 3rd dayNYSDOHDRAFT--DO NOT QUOTE OR CITEB-7October 2002Table 1.Overview of monitoring locations and responsible parties (cont’d).Site NameSite LocationPollutants MeasuredSampling FrequencyAnalyticalLaboratoryIV.Extended Monitoring Network- EPA/ORDNumbered Air Monitoring Stations (cont’d)16290 BroadwayNY, NYPAHs & SVOCs12 & 23 hour samplesORDParticulatescontinuousORDNotes for Table.Column1: Site Name- Though not “lettered”, the WTC - Building 5 SWsite and the Staten Island Landfill Sites have been run by EPA’sEnvironmental Response Teamand are included here.- The New Jersey Department of Environmental Protection (NJDEP) site names were designated by NJDEP- Locations C (Liberty & Trinity) and C1 (Liberty and Broadway), and 3 (WTC Building 5) and 3A (Church & Vesey) were“alternate” pairs ofstations, meaning that sample dates alternated between the paired sites.- 290 Broadway was a sample site that measured several contaminants, but only on 1 date, October 10, 2001.Because therewas only one date of sampling, this site is not listed above.Column2: Site Location:Column3: Pollutants Measured:- Dioxin (1) = 72-hr samples collected by EPA Departmentof Environmental Science and Assessment (DESA) Region 2personnel and analyzed by Region 7.- Dioxin (2) = 8-hr samples collected by EPA Emergency and Remedial Response Division (ERRD) Region 2 personnel andanalyzed by a contract laboratory.Column4: Analytical Laboratories:- Contract = Laboratories contracted by EPA to conduct analysis.- ORD =Human Exposure and Atmospheric Sciences Division (HEAS) in the National Exposure Research Laboratory(NERL), in Research Triangle Park, North Carolina.- Region 7 = Regional Laboratory Branch, in the EnvironmentalServices Division (ESD) in Region 7, Kansas City, Kansas.DRAFT--DO NOT QUOTE OR CITEB-8October 2002