National Survey of Lead and Allergens in Housing

Volume I:  Analysis of Lead Hazards

FINAL REPORT

Revision 7.1

October 31, 2002

Prepared for:

Office of Healthy Homes and Lead Hazard Control

U.S. Department of Housing and Urban Development

451 7th Street, N.W.

Washington, D.C.  20410

Project Officers:

Warren Friedman, Ph.D., CIH

Joey Zhou, Ph.D.

Prepared by:

Westat, Inc.

1650 Research Boulevard

Rockville, MD  20850

Robert P. Clickner, Ph.D.

David Marker, Ph.D.

Susan M. Viet, Ph.D., CIH

John Rogers

Pamela Broene

This work was conducted under HUD Contract Number C-OPC-21356.

Table of Contents

Chapter	Page

EXECUTIVE SUMMARY		ES-1

1.	INTRODUCTION 	1-1

	1.1	Background	1-1

	1.2	Survey Objectives	1-3

		1.2.1	Technical Note on the Survey Weights	1-4

	1.3	Report Organization	1-4

2.	SURVEYED HOUSING POPULATION	2-1

3.	LEAD-BASED PAINT (LBP) HAZARDS IN HOUSING	3-1

	3.1	Definition of Significant Lead-Based Paint (LBP) Hazards	3-1

	3.2	Prevalence of Significant Lead-Based Paint Hazards in Housing	3-2

	3.3	Prevalence of Lead-Related Occupations or Hobbies	3-11

4.	LEAD-BASED PAINT (LBP) IN HOUSING	4-1

	4.1	Prevalence of Lead-Based Paint 	4-1

	4.2	Prevalence of Deteriorated Lead-Based Paint 	4-8

	4.3	Paint Lead Loadings in Housing	4-10

4.4	Comparison of Prevalence of Lead-Based Paint (LBP)

			to the 1990 LBP Survey	4-14

	4.5	Amount of Lead-Based Paint in Housing	4-17

5.	DUST LEAD IN HOUSING	5-1

	5.1	Prevalence of Dust Lead in Housing	5-1

	5.2	Dust Lead Loadings in Housing	5-3

	5.3	Association between Interior Dust Lead Hazards and Interior LBP
Condition	5-19

6.	RESIDENTIAL SOIL LEAD	6-1

	6.1	Prevalence of Residential Soil Lead Over All Sampled Locations	6-1

	6.2	Association Between Soil Lead and Exterior Paint Condition	6-6

	6.3	Prevalence of Bare Soil Lead in Children’s Play Areas	6-8

	6.4	Prevalence of Bare Soil Lead in the Rest of the Yard	6-11

	6.5	Comparison of Prevalence of Soil Lead to the 1990 LBP Survey	6-13

7.	QUALITY OF THE NATIONAL SURVEY DATA	7-1

	7.1	Statistical Concepts and Terminology	7-1

	7.2	Potential for Nonresponse Bias	7-2

		7.2.1	Analysis of Completion and Response Rates	7-2

7.2.2	Comparison of  “Hard to-Recruit” Versus

	“Easy-to-Recruit” HUs	7-7

		7.2.3	Completion Rates in the Play Area Subsample	7-8

	7.3	Quality of Field Data Collection and Analysis	7-10

				7.3.1	Field Data Collection	7-10

				7.3.2	Laboratory Quality Control Samples	7-13

				7.3.3	Laboratory Selection Quality Assurance	7-14

	7.4	Paint Testing Quality Assurance	7-14

List of Appendices

Appendix A	SELECTED ADDITIONAL TABLES AND FIGURES	A-1

APPENDIX B	COMPARISON OF PROTOCOLS FOR THE HUD 1990 SURVEY

				OF LEAD-BASED PAINT (LBP) AND THE HUD NATIONAL

				SURVEY OF LEAD AND ALLERGIES IN HOUSING	B-1

APPENDIX C	Correcting for Classification Bias Due to Measurement

				Error	C-1

APPENDIX D	CALCULATION OF SOIL RELATED ESTIMATES	D-1

List of Tables

Table ES.1	Summary Estimates of Prevalence of Lead-Based Paint and
Lead-Based

		Paint Hazards	ES-2

Table ES.2	Type of Lead-Based Paint Hazard	ES-3

Table 2.1	Characteristics of the Survey Population, with Comparisons to
the American

		Housing Survey (AHS) and the Current Population Survey (CPS)	2-4

Table 3.1	Prevalence of Housing Units with Significant Lead-Based Paint
(LBP) Hazards,

		by Selected Characteristics	3-5

Table 3.2	Prevalence of Significant Lead-Based Paint (LBP) Hazards by
Location in

		the Building	3-8

Table 3.3	Prevalence of Significant Lead-Based Paint (LBP) Hazards in
Housing Units

		with a Child Under 6 years of Age by Type of Hazard	3-9

Table 3.4	Prevalence of Significant Lead-Based Paint (LBP) Hazards in
Housing Units by

		Type of Hazard and HU Age	3-10

Table 3.5	Prevalence of Housing Units with Selected Lead-Related
Characteristics	3-12

Table 3.6	Prevalence of Selected Lead-Related Characteristics in Homes
with Significant

	Interior LBP Hazards	3-12

Table 4.1	Prevalence of Lead-Based Paint (LBP) by Selected Housing Unit
(HU)

		Characteristics	4-4

Table 4.2	Prevalence of Lead-Based Paint (LBP) by Location in the
Building	4-7

Table 4.3	Prevalence of Deteriorated and Significantly Deteriorated
Lead-Based Paint

		(LBP) by Location in the Building	4-8

Table 4.4	Distribution of Housing Units (HUs) with Deteriorated and
Significantly

		Deteriorated Lead-Based Paint (LBP) by Construction Year	4-9

Table 4.5	Distribution of Paint Lead Loading by Location in the Building
4-11

Table 4.6	Distribution of Paint Lead Loading by Location in the Building
and

		Construction Year	4-12

Table 4.7	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by

		Interior Component Types	4-13

Table 4.8	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by

		Exterior Component Types	4-13

Table 4.9	Percentage of Components with Lead-Based Paint by Component
Type

		And HU Age	4-14

Table 4.10	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by Room

		Type	4-14

Table 4.11	Comparison of the Prevalence of Lead-Based Paint to the 1990
LBP Survey	4-15

Table 4.12	Amount of LBP by Painted Component	4-18

Table 5.1	Prevalence of Housing Units with a Dust Lead Hazard Somewhere
in the Home	5-2

Table 5.2	Distribution of Maximum Dust Lead Loadings in Housing Units by
Surface	5-5

Table 5.3	Distribution of Average Dust Lead Loadings in Housing Units by
Surface	5-7

Table 5.4	Distribution of Dust Lead Loading by Room and Surfaces	5-9

Table 5.5a	Maximum Floor Dust Lead Loading by Year of Construction	5-11

Table 5.5b	Maximum Window Sill Dust Lead Loading by Year of Construction
5-12

Table 5.5c	Maximum Window Trough Dust Lead Loading by Year of
Construction	5-13

Table 5.6a	Maximum Floor Dust Lead Loadings by Household Income	5-14

Table 5.6b	Maximum Window Sill Lead Dust Loadings by Household Income
5-15

Table 5.6c	Maximum Window Trough Lead Dust Loadings by Household Income
5-19

Table 5.7	Estimated Empirical Distribution Parameters of Dust Lead
Loadings by

		Surface Types	5-19

Table 5.8	Association Between Dust Lead Hazards and Presence and
Condition of

		Interior Lead-Based Paint	5-20

Table 5.9	Association Between Floor Dust Lead Loadings and Presence of
Interior

		Lead-Based Paint	5-21

Table 5.10	Association Between Window Sill Dust Lead Loadings and
Presence of Interior

		Lead-Based Paint	5-22

Table 6.1	Distribution of Maximum Bare Soil Sample Lead Concentrations
(All Sampled

		Locations)	6-3

Table 6.2	Distribution of Maximum Bare Soil Sample Lead Concentrations
(All Sampled

		Locations)	6-4

Table 6.3	Estimated Empirical Distribution Parameters of Soil Lead
Concentrations by

		Sample Site	6-6

Table 6.4	Association Between Bare Soil Lead Concentration and Presence
of

		Significantly Deteriorated Exterior LBP, All Sampled Locations	6-7

Table 6.5	Distribution of Maximum Soil Lead Concentrations in
Children’s Play Areas	6-9

Table 6.6	Distribution of Maximum Soil Lead Concentration in
Children’s Play Areas,

		by Construction Year	6-10

Table 6.7	Association Between Bare Soil Lead Concentration and Presence
of

		Significantly Deteriorated Exterior LBP, in Children’s Play Areas
6-11

Table 6.8	Distribution of Maximum Bare Soil Lead Concentrations in the

		Rest of the Yard	6-12

Table 6.9	Distribution of Maximum Bare Soil Lead Concentrations in the
Rest of the

		Yard, by Construction Year	6-13

Table 6.10	Comparison of the Prevalence of Lead-Contaminated Bare Soil
in the

		National Survey and the 1990 LBP Survey	6-14

Table 7.1	Completion Rates by 1990 Census Block Group Characteristics
7-6

Table 7.2	Mean Percents for Completed and Noncompleted Housing Units by
1990

		Census Block Group Characteristics	7-7

Table 7.3	Comparison of “Easy-to-Recruit” Respondents Versus
“Hard-to-Recruit”

		Respondents by Reported Housing Characteristics	7-8

Table 7.4	Completions in Play Area Subsample	7-10

List of Figures

Figure 3.1	Prevalence of Housing Units (HUs) with Significant LBP
Hazards	3-4

Figure 4.1	Prevalence of Lead-Based Paint by Selected Housing Unit
Characteristics	4-2

Figure 4.2	Prevalence of HUs with LBP by Construction Year & Presence of
Children < 6	4-3

Figure 4.3	Prevalence of Lead-Based Paint by Location in the Building
4-7

Figure 4.4	Presence and Condition of LBP by Construction Year	4-10

Figure 5.1	Dust Lead Hazards by Construction Year	5-2

Figure 5.2	Dust Lead Hazards by Household Income	5-3

Figure 5.3	Distribution of Maximum Floor Dust Lead Loadings	5-4

Figure 5.4	Distribution of Maximum Window Sill Dust Lead Loadings	5-4

Figure 5.5	Association Between Dust Lead Loading on Floors and Window
Sills	5-10

Figure 5.6	Box Plots for Dust Lead Loadings by Room	5-17

Figure 5.7	Box Plots for Dust Lead Loadings by Surface	5-18

Figure 5.8	Association Between Dust Lead Hazards and Condition of
Interior

		Lead-Based Paint	5-20

Figure 6.1	Distribution of Maximum Bare Soil Lead Concentrations	6-2

Figure 6.2	Box Plots for Lead in Soil Samples by Sample Site	6-5

Figure 6.3	Association Between Lead in Bare Soil and Significantly
Deteriorated Exterior

		Lead-Based Paint	6-8

Figure 6.4	Distribution of Maximum Bare Play Area Soil Lead
Concentrations	6-9

EXECUTIVE SUMMARY

The National Survey of Lead and Allergens in Housing (NSLAH) was
conducted under the sponsorship of the Department of Housing and Urban
Development (HUD) and the National Institute of Environmental Health
Sciences (NIEHS) to assess children's potential household exposure to
lead and allergens.  The NSLAH measured the levels of lead in dust,
soil, and paint, the prevalence of hazardous levels of lead, and levels
and patterns of various indoor allergens in dust in homes.  Volume I
includes the findings for lead hazards, and describes lead levels in
dust, soil, and paint in the nation’s housing by age, type,
geographical location, and exposed populations.  This Executive Summary
refers to the standards of HUD’s “Lead Safe Housing Rule” (24 CFR
35 Subparts B-R) on Federally-owned and -assisted housing with
thresholds from the EPA "Rule: Identification of Dangerous Levels of
Lead" (40 CFR Part 745).

Results: Extent of Lead-Based Paint and Lead-Based Paint Hazards in
Housing

An estimated 38 million homes (40 percent of all homes) in the United
States have lead-based paint somewhere in the building.  Of these, 20
million homes have lead-based paint present on both interior and
exterior surfaces, 9 million homes have lead-based paint only on the
interior, and another 9 million homes have lead-based paint only on the
exterior.

Although a large number of homes have lead-based paint, most of them
have relatively small surface areas of it.  The average home with
lead-based paint has an estimated 259 square feet of interior lead-based
paint and 996 square feet of exterior lead-based paint.  For comparison,
a room 10 feet by 12 feet with an 8 foot ceiling has a wall area of 352
square feet.

An estimated 24 million (26 percent) homes have significant lead-based
paint hazards somewhere in the building or on the premises; this is
consistent with earlier HUD estimates of 24 million homes.  Based on the
HUD Lead Safe Housing Rule, a home is said here to have a significant
lead-based paint hazard if one or more of the following conditions
exists:  lead-based paint with deterioration larger than de minimis
levels specified in the Lead Safe Housing Rule, dust lead loadings at or
above specified thresholds on floors or window sills; bare soil in
children’s play areas above specified thresholds; or more than 9
square feet of bare soil in the rest of the yard with lead
concentrations at or above specified thresholds.

Of the 16.4 million homes with one or more children under age 6, an
estimated 4.2 million (25 percent) have significant lead-based paint
hazards.  Of all 4.8 million homes with household incomes under $30,000
and one or more children under age 6, an estimated 1.2 million (25
percent) have significant lead-based paint hazards.  Thus, one in four
homes with young children among the residents have significant
lead-based paint hazards.  Table ES.1 summarizes these basic estimates
of the prevalence of lead-based paint and significant lead-based paint
hazards.

Table ES.1	Summary Estimates of Prevalence of Lead-Based Paint and
Lead-Based Paint Hazards

Housing Unit Characteristica

Number of Housing Units (millions)	Number of Housing Units with
Lead-Based Paint

(millions)	Number of Housing Units with Significant Lead-Based Paint
hazards

(millions)

Total housing units	95.7	37.9	24.0

One or more children under age 6	16.4	5.3	4.2

One or more children under age 6, less than $30,000/year household
income	4.8	1.4	1.2

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

Of the 24 million homes with significant lead-based paint hazards, an
estimated 15 million have interior dust lead hazards, 14 million have
deteriorated lead-based paint at or above de minimis levels and 6
million have soil lead hazards, as displayed in Table ES.2.

Table ES.2	Type of Lead-Based Paint Hazard

Type of Hazard	Number of Housing Units

(millions)	Percentage of Housing Unitsa

	Estimate	95% CIb	Estimate	95% CI

Significantly Deteriorated lead-based paint	13.63	10.9 – 16.3	14	11-17

Interior lead-contaminated dust	15.47	13.0 – 18.0	16	14-19

Lead-contaminated soil	6.46	3.1 – 9.8	7	3-10

Any lead-based paint hazard	24.03	21.3 – 26.7	25	22-28

a	All percentages are calculated with total housing units (95,688,000)
as the denominator; percentages may not total 100% due to rounding.

b	95% CI = 95 percent confidence interval.

Dust lead levels above the Lead Safe Housing Rule’s standards are
associated with the presence of interior lead-based paint.  An estimated
29 million homes have some interior lead-based paint, of which 39
percent have dust lead levels above the Lead Safe Housing Rule’s
standards.  In contrast, only 6 percent of the 67 million homes without
interior lead-based paint have dust levels above the Lead Safe Housing
Rule’s standards.

Soil lead levels above the Lead Safe Housing Rule’s standards are
associated with the presence of deteriorated exterior lead-based paint.
Homes with deteriorated exterior lead-based paint above de minimis
levels are six times more likely to have soil lead hazards than are
homes free of such deteriorated lead-based paint.

This most recent HUD survey shows that the number of housing units with
lead-based paint has declined from 64 million in 1990 to 38 million ten
years later.  On the other hand, the prevalence of homes with
deteriorating lead-based paint increased slightly, from 19% to 22%.

Survey Design and Methodology

The principal lead-related purpose of the NSLAH was to develop a
scientific description of the existing lead levels in paint, dust, and
soil in the nation’s housing. Additional objectives were to obtain
data to:  (1) estimate the number and percent of homes with dust and
soil lead levels above selected thresholds;  (2) identify sources of
lead in dust in housing, e.g., paint and soil;  (3) permit future
analyses of lead hazard control strategies and costs, e.g., quantities
of deteriorated painted surfaces; and (4) permit future analyses for
regulation, policy, and guidance that minimize regulatory and program
implementation burden.

The target population included approximately 96 million homes, of the
112 million total homes in the nation, including single- and
multi-family buildings and manufactured housing units, e.g., mobile
homes and trailers.  Homes built in all age categories were included.
Vacant housing, group quarters, and hotels and motels were excluded for
reasons of difficulties gaining cooperation.  Housing where children
were not permitted to live, e.g., elderly care facilities, were excluded
because the primary interest was in children’s exposure to lead.
Thus, 16 million units out of 112 million total units were excluded from
this survey.

The main field survey was conducted in 1998-1999, with an augmentation
of the soil sampling in 2000 to include additional play area samples.  A
nationally-representative sample of 1,984 homes was drawn from 75
clusters (each a metropolitan statistical area (MSA) or a group of
counties that have a minimum population of 15,000) called primary
sampling units (PSUs). A total of 831 eligible homes were recruited and
completed the survey.

Four rooms were randomly selected for environmental sample collection
and testing from each of four room types:  kitchen, common living areas,
bedrooms (preferably those occupied by children), and other rooms.  In
each of these four rooms floor, window sill, and window trough dust
samples were collected, painted surfaces were measured for lead content,
and the condition of painted surfaces was assessed.  Outside the
building, soil samples were taken and exterior painted surfaces were
tested.  A floor dust sample was collected in the interior common area
of multi-family buildings.

Measurements of lead in paint were made by State- or EPA-certified
lead-based paint inspectors using an XRF analyzer and a protocol based
on HUD's 1997 Guidelines’ inspection procedure.  The instrument model
used does not require making substrate corrections, nor have an
inconclusive range, both of which involve destructive sampling of
painted surfaces.  One XRF reading was made per painted component in
each room, approximately in the center of a randomly selected quadrant
of the total building component surface area.

Single wipe dust samples were collected by the technique described in
ASTM E 1728-95. Floor dust samples were collected in the center of the
largest open floor area in the room.  The floor samples in the major
entrance and interior common area were collected approximately six
inches away from the center of the doorway.  One-square-foot templates
were used for floor samples.  Window sill and trough samples were
collected from a random, openable window in each selected room.  The
entire area was wiped for window sill and trough samples (up to two
square feet).  All dust samples were analyzed by flame atomic absorption
spectrophotometry, using the Environmental Protection Agency’s
(EPA’s) SW-846 method 3050 digestion method and the American
Industrial Hygiene Association’s Environmental Lead Laboratory
Accreditation Program (ELLAP) proficiency testing procedures.  The
laboratory that performed the analysis was NLLAP – recognized for dust
lead analyses.

Soil sampling was conducted in accordance with core sampling procedures
described in ASTM E 1727-95.  Only the top one-half inch of each soil
core, i.e., that portion most accessible to children, was included in
the sample.  Where necessary, grass or leaf covering was gently removed
before taking the core.  Soil samples were taken outside the building at
the major entrance, and along the dripline and mid-yard area of two
sides of the building.  Soil samples were collected from children’s
play areas in a subsample of 375 homes.  Soil samples were analyzed by
inductively-coupled plasma atomic emission spectroscopy, using the
SW-846 digestion method and the ELLAP proficiency testing procedures.
The laboratory that performed the analysis was NLLAP – recognized for
dust lead analyses.

1.  INTRODUCTION

The National Survey of Lead and Allergens in Housing (NSLAH) was
conducted under the sponsorship of the Department of Housing and Urban
Development (HUD) and the National Institute of Environmental Health
Sciences (NIEHS) to assess children's potential household exposure to
lead and allergens, i.e., to estimate the levels of lead in dust, soil,
and paint, the prevalence of hazardous levels of lead, and levels and
patterns of various indoor allergens (allergy-inducing substances) in
dust in homes.  Combining the goals of HUD and NIEHS into a single
survey saved significant public funds, reduced the survey response
burden on the public, and substantially reduced the time required to
obtain the data needed by both agencies for their ongoing primary and
secondary prevention activities.

This report, Volume I, includes the findings for lead hazards, and
describes lead levels in dust, soil, and paint in the nation’s housing
by age, type, geographical location, and exposed populations.  In
addition, the report estimates the number and percent of homes with dust
and soil lead levels above selected thresholds, especially thresholds in
HUD’s Lead Safe Housing Rule (24 CFR Part 35 Subparts B-R,
Requirements for Notification, Evaluation and Reduction of Lead-Based
Paint Hazards in Federally Owned Residential Property and Housing
Receiving Federal Assistance, effective September 15, 2000), and EPA's
Final Rule: Identification of Dangerous Levels of Lead (40 CFR 745),
effective March 6, 2001.

1.1	Background

Lead is a toxin that affects the central nervous system and is
particularly damaging to the developing nervous system of young children
and fetuses.  High blood lead levels can result in convulsions, mental
retardation, and even death. Research has shown that even low lead
levels can have serious health consequences.  These include reduced
intelligence and short-term memory, slower reaction times, poorer
hand-eye coordination, reduced height, hearing problems, and numerous
behavioral problems.

Although there are many sources of lead in the environment, including
drinking water, food, emissions from gasoline combustion, and industrial
emissions, it is clear that lead-based paint (LBP) plays a major role in
high blood lead levels among children today.  Research indicates that
dust and soil are the most significant pathways for children's lead
exposure, and that LBP is the major important source of household dust
lead.,

The fundamental purpose of the Residential Lead-Based Paint Hazard
Reduction Act of 1992, which is Title X of the Housing and Community
Development Act of 1992 (P.L. 102-550) is prevention, i.e., to find and
mitigate LBP hazards in homes before children are poisoned.  In Sections
1051 and 1052(10), Congress required HUD to conduct research on risk
reduction strategies from household-based lead exposure, and to assess
the effectiveness of lead hazard evaluation activities, respectively.
The NSLAH was undertaken to provide current information needed for
regulatory and policy decisions and for assessment of the effectiveness
of lead hazard reduction strategies, e.g., lead information disclosure
during housing sale or lease transactions and certification of LBP
professionals.

In 1989-1990, HUD sponsored a national survey of LBP in housing
(referred to as the 1990 LBP Survey).  The primary objective of that
survey was to estimate the prevalence of LBP in housing - not to address
the presence of lead-based hazards in the housing.  Since 1990, there
have been advances in the understanding of the sources and pathways of
lead transport and exposure, advances in the protocols for collecting
samples of paint and dust for lead contamination, and improvements in
the understanding of the susceptibility of children to the effects of
lead exposure in the intervening years.  For example, it is now
understood that lead-contaminated house dust from LBP is most often the
primary lead hazard for children.,,  Also, HUD now recommends, and HUD
and EPA require in their regulations, the use of dust wipe sampling as
opposed to the vacuum sampling employed in the 1990 LBP Survey.  In
addition, the 1990 survey data are dated because the housing stock has
continued to evolve as older houses are renovated, repaired, and/or
demolished.  Thus, it may not serve as an appropriate estimate for
evaluation of current LBP hazard reduction strategies.  Finally, the
1990 LBP Survey excluded certain housing categories such as manufactured
housing, and housing built after 1979 (i.e., after the Consumer Product
Safety Commission’s ban on lead-containing residential paint went into
effect).

The NSLAH has updated HUD's 1990 LBP Survey and will enable an
assessment of progress in making the U.S. housing stock lead-safe.
Further, it provides current baseline information needed for regulatory
and policy decisions and for assessment of the effectiveness of lead
hazard reduction strategies currently under development.

1.2	Survey Objectives

HUD’s principal lead-related purpose for the NSLAH was to develop a
scientific description of the existing lead levels in dust, soil, and
paint in the Nation’s housing.  In addition, the survey of lead
hazards in homes collected data to:

Estimate the number and percent of homes with dust and soil lead levels
above selected thresholds.

Identify likely sources of lead in dust in housing, e.g., paint and
soil.

Permit future analyses of lead hazard control strategies and costs,
e.g., quantities of deteriorated painted surfaces.

Permit future analyses for regulation, policy, and guidance that
minimize regulatory and program implementation burden.

In order to meet the survey objectives, a nationally-representative
sample of 1,984 housing units (HUs) was drawn from 75 clusters called
primary sampling units (PSUs).  A general three-stage sample design was
utilized to accomplish these goals as efficiently as possible.  A total
of 831 eligible HUs were recruited into the survey.  In each recruited
HU, samples of dust and soil were collected and painted surfaces were
tested.  (See Volume II: Design and Methodology for details on design
and data collection protocols.)

1.2.1	Technical Note on the Survey Weights and Estimation Procedure

Paint lead measurements, dust samples, and general area soil samples
were collected from all 831 homes in the sample.  In contrast, data on
the presence of children’s play areas and play area soil samples were
collected from a nationally representative statistical subsample of 375
homes in the sample.  Consequently, two sets of survey sampling weights
have been developed:  one for the full sample of 831 surveyed homes; and
one for the subsample of 375 homes with play area soil lead data.  The
construction of these weights is described in Volume II.  Both sets of
weights are unbiased; they will both produce unbiased national estimates
to characterize the target population of all 95.7 million occupied
housing units in the U.S. where children are permitted to live.
However, the play area subsample, being smaller, produces wider
confidence intervals than the full sample.  To minimize the impact of
this fact and produce the most efficient possible estimates, the
following procedure was adopted.  Data from all 831 homes were used to
estimate paint, dust, and non-play-area soil lead hazards; then data
from the 375 home subsample were used to estimate the added number of
homes with only play area soil lead hazards.  Further details on this
estimation procedure are provided in Appendix D.

1.3	Report Organization

The report for the NSLAH consists of two volumes:  Volume I presents the
major lead hazard findings.  Volume II presents the survey design and
methodology.

There are seven chapters in Volume I, including this introduction.
Descriptions of each chapter are as follows:

Chapter 2 describes the population surveyed and compares the survey
population to Current Population Survey (CPS) and American Housing
Survey (AHS) populations.

Chapter 3 presents the estimates of the prevalence of significant LBP
hazards in housing, based on the findings presented in Chapters 4, 5,
and 6 for paint, dust, and soil, respectively.  The association between
lead in each of the matrices (paint, dust, soil) is presented, as well
as the prevalence of lead-related occupations and hobbies among housing
residents.

Chapter 4 presents the estimates of the prevalence and amount of LBP
and deteriorated LBP in housing, including paint lead loadings in
housing. Relevant estimates are compared with the findings of the 1990
LBP Survey.

Chapter 5 presents the estimates of the prevalence of lead-contaminated
dust in housing, including the dust lead loadings and the association
between interior dust lead and LBP condition.  Relevant estimates are
compared with the findings of the 1990 LBP Survey.

Chapter 6 presents the estimates of the prevalence of residential soil
lead, including soil lead concentrations and the association between
soil lead and exterior LBP condition.  Relevant estimates are compared
with the findings of the 1990 LBP Survey.

Chapter 7 examines the quality of the data and the resulting quality of
projected national estimates.  The chapter addresses nonresponse rates
and provides a summary of field data collection quality control
activities.  Classification bias due to measurement error is discussed
in Appendix C.

2.  Surveyed housing population

The National Survey of Lead and Allergens in Housing (NSLAH) population
included the national housing stock of permanently-occupied,
noninstitutional housing units (HUs), including multi-family buildings
and manufactured HUs, i.e., mobile homes and trailers.  Homes built in
all age categories in all 50 states and the District of Columbia were
included.  Homes built before 1978 were included to update and expand
upon the findings of the 1990 LBP Survey.  Homes built in 1978 or after
were included to verify the assumption that newer homes have minimal
lead hazards, based on the 1978 ban of lead-based paint (LBP) for
residential use.  Vacant housing, group quarters, hotels and motels,
military bases, and short-term housing were excluded because of
difficulties gaining cooperation and are consistent with exclusions
under the Lead Safe Housing Rule.  Housing where children were not
permitted to live, e.g., elderly care facilities, were excluded because
the primary interest of the survey was in children’s exposure to lead
and allergens.  However, a home was not excluded simply because a child
was not currently residing in the home at the time of the survey.  With
these exclusions, the eligible national housing stock consisted of
approximately 96 million housing units.

A nationally-representative sample of 1,984 HUs was drawn from 75
clusters called primary sampling units (PSUs).  A total of 831 eligible
HUs were recruited and completed the survey.  Table 2.1 presents the
national estimates for selected characteristics of the survey
population, including geographic region, year of construction, degree of
urbanization, presence of children under age 6 and age 18, tenure,
income, poverty, government support, race, and ethnicity.  All estimates
presented are weighted national estimates as discussed in Volume II.
Chapter 7 and Appendix C of this volume presents an extensive discussion
of the potential effect of nonresponse bias.

One important measure of the representativeness of the NSLAH is to
examine how the distributions of the housing characteristics,
socioeconomic and demographic factors compare to national distributions.
 National distributions were obtained from the 1997 American Housing
Survey (AHS) and the 1998 and 1999 Current Population Surveys (CPS).
The weighted percent distribution of the NSLAH sample by race,
ethnicity, income, presence of a child under 18, Census region, year of
construction, single family vs. multi-family, metropolitan status, and
tenure (owned vs. rented) were compared with that of the available AHS
and CPS data.

The 95 percent confidence intervals for the NSLAH sample estimate were
found to contain the AHS or CPS estimate for most of the available
statistics.  Slight differences in estimates were observed as follows:

The 1997 AHS estimate of 35 percent of all homes being in the South is
slightly lower than the survey estimate of 36 percent to 39 percent of
all homes being in the South.

The 1997 AHS estimate of 37 percent of all homes having children under
age 18 is slightly lower than the survey estimate of 38 percent to 39
percent of all homes.

The 1998 CPS estimate of 26 percent of all household incomes falling in
the $0-19,999 range is slightly higher than the survey estimate of 17
percent to 24 percent of all households in this income range.

The 1998 CPS estimate of 85 percent of all households not in poverty is
slightly higher than the survey estimate of 77 percent to 83 percent of
all households not in poverty.

A few items should be noted which affect the comparability of the
estimates and may explain the above observed differences.  The first is
that the target population for the National Survey excludes housing that
excludes children, whereas the AHS and CPS estimates include such
housing.  Second, the cut-offs used for defining urbanization were not
exactly the same for the NSLAH and the CPS.  The NSLAH used a cut-off of
2,100,000 while the CPS used 2,500,000.  Third, for the income and
poverty comparisons, the CPS uses the family size and income to
determine poverty status, whereas the NSLAH has used household size and
income.  The NSLAH estimates of any particular income class are also
deflated due to the 9 percent of respondents whose income level is
unknown.  Similarly, there are 6 percent of respondents whose poverty
status is unknown.  Fourth, race and ethnicity are based on the youngest
household member for the NSLAH, while the AHS bases these data on the
first householder identified over the age of 18. Fifth, the most recent
AHS available is for 1995 and 1997, thus the AHS data are slightly out
of date as compared to the NSLAH. Finally, there is a small amount of
sampling error in both the AHS and CPS estimates, and in the standard
error estimates for all three surveys.  The standard error for both AHS
estimates (percent of homes in the south, percent of homes with children
under age 18) is approximately 0.25%.  The difference between the NSLAH
and AHS estimates is still statistically significant for both variables.
 CPS standard errors are of a comparable magnitude to those for the AHS
(similar sample sizes and designs) and also do not affect the
statistical significance of the results.

Table 2.1	Characteristics of the National Survey Population, with
Comparisons to the American Housing Survey (AHS) and the Current
Population Survey (CPS)

HU Characteristic	National Survey Estimates	HUs in sample	AHS

(1997)	CPS

(1998-99)c

	Estimate (000)	Estimate (%)a	Lower 95% CIb (%)	Upper 95% CI (%)

	Total Housing Unitsd	95,688	100%

	831

Region:

	Northeast	19,290	20%	19%	22%	155	20%

	Midwest	22,083	23%	22%	24%	196	24%

	South	35,474	37%	36%	39%	277	35%

	West	18,841	20%	18%	21%	203	21%

	Construction year:

	1978-1998	29,774	31%	30%	32%	220	30%

	1960-1977	27,874	29%	28%	30%	267	30%

	1940-1959	20,564	21%	20%	23%	186	20%

	Before 1940	17,476	18%	17%	20%	158	20%

	Region by Construction year:

	Northeast	19,290	20%	19%	22%	155	20%

	1978-1998	4,358	5%	3%	6%	30	3%

	1960-1977	3,754	4%	3%	5%	30	5%

	1940-1959	4,261	5%	4%	5%	36	4%

	Before 1940	6,917	7%	6%	8%	59	7%

	Midwest	22,083	23%	22%	24%	196	24%

	1978-1998	4,801	5%	4%	6%	41	6%

	1960-1977	6,283	7%	6%	7%	55	7%

	1940-1959	5,899	6%	5%	7%	47	5%

	Before 1940	5,101	5%	5%	6%	53	6%

	South	35,474	37%	36%	39%	277	35%

	1978-1998	14,447	15%	14%	17%	95	14%

	1960-1977	11,261	12%	11%	12%	96	12%

	1940-1959	6,320	7%	6%	7%	57	6%

	Before 1940	3,445	4%	3%	4%	29	4%

	West	18,841	20%	17%	21%	203	21%

	1978-1998	6,169	6%	5%	8%	54	8%

	1960-1977	6,536	7%	6%	7%	85	7%

	1940-1959	4,124	4%	3%	6%	47	4%

	Before 1940	2,013	2%	1%	3%	17	2%

	Urbanization:

	1999

MSA equal to or above

  2 million population	26,814	28%	24%	32%	276

30%

MSA below 2 million

  Population	45,753	48%	43%	53%	417

47%

Non-MSA	23,121	24%	19%	30%	138

23%

Table 2.1	Characteristics of the Survey Population, with Comparisons to
the American Housing Survey (AHS) and the Current Population Survey
(CPS) (continued)

HU Characteristic	National Survey Estimates	HUs in sample	AHS

(1997)	CPS

(1998-99)3

	Estimate (000)	Estimate (%)	Lower 95% CI (%)	Upper95% CI (%)

	One or more children under age 6:	16,402	17%	15%	19%	184	17%

	Refusal/Don’t Knowe	352

5

One or more children under age 18:	36,994	39%	38%	39%	398	37%

	Refusal/Don’t Know	290

3

Housing Unit Type:

	Single family	82,651	86%	84%	89%	705	88%

	Multi-family	13,037	14%	11%	16%	126	12%

	Tenure:

	1999

Owner-occupied	66,232	69%	65%	73%	539

67%

Renter-occupied	29,074	30%	27%	34%	289

33%

Refusal/Don’t Know	381

3

Household Income

  ($30,000):

	1998

Less than $30,000/year	33,830	35%	30%	41%	309

40%

Equal to or more than

  $30,000/year	56,111	59%	54%	63%	482

60%

Refusal/Don’t Know	5,747

40

Household Income

  ($20,000):

	1998

$0-19,999/year	19,359	20%	17%	24%	189

26%

$20-39,999/year	25,855	27%	23%	31%	228

27%

$40-59,999/year	19,316	20%	16%	25%	152

19%

Equal to or more than

  $60,000/year	22,890	24%	20%	28%	203

28%

Refusal/Don’t Know	8,268

59

Government Support:

	Government support	4,809	5%	3%	7%	54

No Government support	86,070	90%	88%	92%	733

Refusal/Don’t Know	4,809	5%

	44

Poverty:

	1998

In poverty	13,221	14%	11%	16%	137

15%

Not in poverty	76,336	80%	77%	82%	651

85%

Refusal/Don’t Know	6,130	6%

	43

Table 2.1	Characteristics of the Survey Population, with Comparisons to
the American Housing Survey (AHS) and the Current Population Survey
(CPS) (continued)

HU Characteristic	National Survey Estimates	HUs in sample	AHS

(1997)	CPS

(1998-99)3

	Estimate (000)	Estimate (%)	Lower 95% CI (%)	Upper95% CI (%)

	Poverty by Urbanization:

	MSA equal to or above 2 million population	26,814	28%	24%	32%	276

In poverty	2,962	3%	2%	4%	35

Not in poverty	22,005	23%	19%	27%	226

Refusal/Don’t Know	1,847	2%

	15

MSA below 2 million population	45,753	48%	43%	53%	417

In poverty	6,996	7%	5%	9%	75

Not in poverty	35,786	37%	34%	41%	323

Refusal/Don’t Know	2,971	3%

	19

Non-MSA	23,121	24%	19%	30%	138

In poverty	3,264	3%	2%	5%	27

Not in poverty	18,544	19%	14%	25%	102

Refusal/Don’t Know	1,313	1%

	9

Race:

	White	77,005	80%	78%	83%	622	83%

	African American	10,365	11%	9%	13%	116	12%

	Otherf	6,571	7%	5%	8%	77	6%

	Refusal/Don’t Know	1,746	2%

	16

Ethnicity:

	Hispanic/Latino	7,434	8%	6%	10%	86	9%

	Not Hispanic/Latino	87,008	91%	88%	93%	736	91%

	Refusal/Don’t Know	1,246	1%

	9

a	All percentages are calculated with total housing units (95,688) as
the denominator.  Percentages may not total 100% due to rounding.

b	CI = 95% confidence interval for the estimated number or percent.

c	Current Population Survey (CPS) data was taken from either 1998 or
1999 CPS, as indicated by the boldface year at the top of each section
of the column.

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	Refusals and “don’t know” responses by survey respondents.

f	“Other” race includes Asian, American Indian or Alaskan Native,
Native Hawaiian or other Pacific Islander, and more than one race.

3.  LEAD-BASED PAINT (LBP) HAZARDS IN HOUSING

Chapter 3 presents the estimates of the prevalence of lead-based paint
(LBP) hazards in housing, based on the findings presented in Chapters 4,
5, and 6.  The associations between lead in each of the matrices (paint,
dust, soil) are presented.  In addition, the prevalence of lead-related
behaviors, occupations, and hobbies among housing residents is
presented.  No comparison is made with the dust lead findings of the
1990 LBP Survey because the concept of hazard from the earlier survey is
not comparable to the definitions in use today.  The effect of
measurement error on the estimates is discussed in Appendix C.

3.1	Definition of Significant Lead-Based Paint (LBP) Hazards

Under Title X, a LBP hazard is defined as “any condition that causes
exposure to lead from lead-contaminated dust; bare, lead contaminated
soil; LBP that is deteriorated; or LBP present on accessible surfaces,
friction surfaces, or impact surfaces.”  Because the data collection
protocol of the NSLAH was not designed as a conventional risk assessment
due to the statistical and operational considerations discussed below,
this report defines significant lead-based paint (LBP) hazards based on
the HUD Lead Safe Housing Rule (24 CFR 35.1320) and EPA Lead Hazards
Identification Rule (40 CFR 745.65).  If any of the following situations
exist at any location in a home, a significant LBP hazard exists in the
home under this definition:

Deteriorated LBP - LBP with deterioration larger than the de minimis
levels per Section 35.1350(d) of the Lead Safe Housing rule -
deterioration of more than 20 square feet (exterior) or 2 square feet
(interior) of LBP on large surface area components (walls, doors), or
damage to more than 10% of the total surface area of interior small
surface area components (window sills, baseboards, trim).  LBP is
defined as any paint or other surface coating (e.g., varnish, lacquer,
or wallpaper over paint) that contains lead equal to or greater than 1.0
mg/cm2); or

Lead-contaminated dust - Dust on floors with greater than or equal to 40
µg/ft2 lead, dust on window sills with greater than or equal to 250
µg/ft2 lead; or

Lead-contaminated bare soil – More than 9 square feet of bare soil
with a lead concentration greater than or equal to 1,200 ppm, or 400 ppm
for bare soil in an area frequented by a child under the age of 6 years.

It is important to note the distinctions between the significant LBP
hazards defined here, and the LBP hazards as defined in the EPA Lead
Hazards Identification Rule, which does not specify de minimis levels
for deteriorated LBP and non-play area bare soils.  In addition, the
significant LBP hazards for dust and soil as used in this report,
although applying the same numerical thresholds of the EPA Lead Hazards
Identification Rule, are based on the maximum dust lead and soil lead
measurements, while the EPA thresholds are based on the average dust
lead and soil lead measurements.

The NSLAH used a statistically-based sampling strategy in order to
obtain statistically valid national estimates. The NSLAH took fewer
measurements in a home than a full risk assessment because of the
statistically-based strategy of maximizing the number of housing units
tested (to yield the most representative national prevalence estimates
with the resources available), and HUD's intention to minimize the
burden on occupants of the housing units being tested. The subset of
rooms and components within each home was randomly selected and
evaluated in the NSLAH so that all work - including allergen sampling -
could be completed in a 2-to-3 hour period in each home. For the same
reasons, the survey did not assess chewable surfaces, friction surfaces,
or impact surfaces as required for conventional risk assessments. In
summary, the statistical nature, operational constraints, and objectives
of the NSLAH  required  defining significant LBP hazards in the manner
shown above.

Under this definition, a home is described as having significant LBP
hazards somewhere in the home if any significant LBP hazard exists at
any location in the home. All tables and figures on housing units with
significant LBP hazards in this report use this definition.

3.2	Prevalence of Significant Lead-Based Paint Hazards in Housing

An estimated 24 million ((3 million) or 25 percent ((3%) of housing
units in the United States have significant LBP hazards. Figure 3.1
presents the number of housing units with significant lead-based paint
hazards by selected characteristics, including the presence of a
resident child under six years of age, housing unit age, measures of
household income, race, and ethnicity.  Table 3.1 presents the number
and percentage of housing units with significant lead-based paint
hazards by a much wider range of housing unit and household
characteristics.

Homes in Northeastern and Midwestern states are more likely to have
significant LBP hazards than homes in Southern or Western states.  An
estimated 40 percent ((10%) of homes in the Northeast have significant
LBP hazards, while the estimates are 17 percent ((4%) and 15 ((6%)
percent for homes in the South and West, respectively.  Older homes are
more likely to have significant LBP hazards than newer homes.  An
estimated 8 percent ((4%) of homes built between 1960 and 1977 have
significant LBP hazards, but the percentage increases to 43 percent
((10%) for homes built between 1940 and 1959, and to 68 percent ((11%)
for homes built before 1940.  A similar pattern of results was found for
homes with children under age 6 categorized by age of construction.

Figure 3.1	 Prevalence of Housing Units (HUs) with Significant LBP
Hazards

 Table 3.1	Prevalence of Housing Units with Significant Lead-Based
Paint (LBP) Hazards, by

Selected Characteristics

HUD Lead Safe Housing Rule:  Significant LBP Hazardsa

Characteristic	All HUs

(000)b	No. of HUs with Significant LBP Hazards (000)	Percent of HUs with
Significant LBP Hazards (%)c	HUs in Sample

Estimate	Lower

95% CId	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Total Occupied HUs 	95,688	24,026	21,307	26,746	25%	22%	28%	831

Region:

Northeast	19,290	7,679	5,748	9,611	40%	30%	50%	155

Midwest	22,083	7,250	6,402	8,097	33%	29%	37%	196

South	35,474	6,191	4,964	7,419	17%	14%	21%	277

West	18,841	2,906	1,856	3,956	15%	10%	21%	203

Construction Year:

1978-1998	29,774	1,042	169	1,915	3%	1%	6%	220

1960-1977	27,874	2,340	1,445	3,235	8%	5%	12%	267

1940-1959	20,564	8,826	6,720	10,933	43%	33%	53%	186

Before 1940	17,476	11,818	10,045	13,591	68%	57%	78%	158

Region by Construction Year:

Northeast

HUs built 1978-1998	4,358	76	0	225	2%	0%	5%	30

HUs built 1960-1977	3,794	1,478	348	2,609	39%	9%	69%	31

HUs built 1940-1959	4,221	3,089	2,179	3,999	73%	52%	95%	35

HUs built before 1940	6,917	5,957	5,187	6,728	86%	75%	97%	59

Midwest

HUs built 1978-1998	4,801	533	0	1,134	11%	0%	24%	41

HUs built 1960-1977	6,283	1,771	872	2,670	28%	14%	42%	55

HUs built 1940-1959	5,899	4,785	4,011	5,559	81%	68%	94%	47

HUs built before 1940	5,101	4,658	3,888	5,429	91%	76%	100%	53

South

HUs built 1978-1998	14,447	1,197	0	2,436	8%	0%	17%	95

HUs built 1960-1977	11,261	1,914	1,216	2,612	17%	11%	23%	96

HUs built 1940-1959	6,320	3,431	2,329	4,532	54%	37%	72%	57

HUs built before 1940	3,445	3,065	2,676	3,453	89%	78%	100%	29

West

HUs built 1978-1998	6,169	225	0	473	4%	0%	8%	54

HUs built 1960-1977	6,536	1,414	816	2,011	22%	12%	31%	85

HUs built 1940-1959	4,124	2,866	1,715	4,017	69%	42%	97%	47

HUs built before 1940	2,013	1,437	376	2,498	71%	19%	100%	17

Urbanization

MSA >= 2 million population	26,814	6,793	4,978	8,609	25%	19%	32%	276

MSA =< 2 million population	45,753	10,232	8,171	12,293	22%	18%	27%	417

Non-MSA	23,121	7,001	3,848	10,153	30%	17%	44%	138

Table 3.1	Prevalence of Housing Units with Significant Lead-Based Paint
(LBP) Hazards, by Selected Characteristics  (continued)

HUD Lead Safe Housing Rule:  Significant LBP Hazards1

Characteristic	All HUs

(000)2	No. of HUs with Significant LBP Hazards (000)	Percent of HUs with
Significant LBP Hazards (%)3	HUs in Sample

Estimate	Lower

95% CI4	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	One or More Children Under Age 6:

All HU ages	16,402	4,155	2,948	5,363	25%	18%	33%	184

HUs built 1978-1998	5,847	<58g	-	-	<1g	-	-	56

HUs built 1960-1977	5,098	469	0	940	9%	0%	18%	61

HUs built 1940-1959	3,055	1,732	1,088	2,375	57%	36%	78%	40

HUs built before 1940	2,401	1,955	1,190	2,720	81%	50%	113%h	27

Housing Unit Type:

Single family	82,651	21,584	18,974	24,194	26%	23%	29%	705

Multi-family	13,037	2,442	1,208	3,676	19%	9%	28%	126

Tenure:

Owner-occupied	66,232	15,305	13,191	17,419	23%	20%	26%	539

Renter-occupied	29,074	8,721	6,583	10,859	30%	23%	37%	289

Refusal/Don’t Knowe	381

	3

Household Income:

Less than $30,000/year	33,830	12,007	9,336	14,679	35%	28%	43%	309

Equal to or more than

  $30,000/year	56,111	10,464	8,250	12,678	19%	15%	23%	482

Refusal/Don’t Know	5,747

	40

One or More Children Under Age 6:

All Income Categories	16,402	4,155	2,948	5,363	25%	18%	33%	184

Less than $30,000/year	4,791	1,201	600	1,801	25%	13%	38%	61

Equal to or more than

  $30,000/year	11,236	2,860	1,763	3,957	25%	16%	35%	117

Refusal/Don’t Know	375

	6

Government Support:

Government support	4,809	805	275	1,335	17%	6%	28%	54

No government support	86,070	22,198	19,252	25,144	26%	22%	29%	733

Refusal/Don’t Know	4,809

	44

Poverty:

In Poverty	13,221	4,976	3,458	6,494	38%	26%	49%	137

Not in Poverty	76,336	16,576	13,598	19,555	22%	18%	26%	651

Refusal/Don’t Know	6,130

	43

Poverty by Urbanization:

MSA equal or above 2

  Million population

In poverty	2,962	1,205	735	1,674	41%	25%	57%	35

Not in poverty	22,005	7,758	5,957	9,559	35%	27%	43%	226

MSA below 2 million

  Population

In poverty	6,996	3,795	2,248	5,341	54%	32%	76%	75

Not in poverty	35,786	12,455	9,722	15,188	35%	27%	42%	323

Table 3.1	Prevalence of Housing Units with Significant Lead-Based Paint
(LBP) Hazards, by Selected Characteristics  (continued)

HUD Lead Safe Housing Rule:  Significant LBP Hazards1

Characteristic	All HUs

(000)2	No. of HUs with Significant LBP Hazards (000)	Percent of HUs with
Significant LBP Hazards (%)3	HUs in Sample

Estimate	Lower

95% CI4	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Non-MSA

In poverty	3,264	1,362	310	2,414	42%	9%	74%	27

Not in poverty	18,544	8,684	5,071	12,297	47%	27%	66%	102

Refusal/Don’t Know if in

  Poverty	6,131

	43

Race:

White	77,005	19,089	16,475	21,703	25%	21%	28%	622

African American	10,365	2,969	1,807	4,131	29%	17%	40%	116

Otherf	6,571	1,496	672	2,321	23%	10%	35%	77

Refusal/Don’t Know	1,746

	16

Ethnicity:

Hispanic/Latino	7,434	2,399	1,235	3,564	32%	17%	48%	86

Not Hispanic/Latino	87,008	21,196	18,674	23,719	24%	21%	27%	736

Refusal/Don’t Know	1,246

	9

a Significant LBP hazard as defined in text and HUD Lead Safe Housing
Rule.

b “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

c All percentages are calculated with the “All HUs” column in each
row used as the denominator.

d CI = 95% confidence interval for the estimated number or percent.

e Refusals and “don’t know” responses by survey respondents.

f “Other” race includes Asian, American Indian or Alaskan Native,
Native Hawaiian or other Pacific Islander, and more than one race.

g No 1978-1988 housing units with one or more children < 6 years old in
this sample have lead-based paint hazards.

h Upper 95% CI value > 100% reflects uncertainty in number of housing
units in first data column.

More homes with lower income occupants have significant LBP hazards than
homes where occupants have higher incomes.  An estimated 35 percent
((8%) of households with less than $30,000/year income have significant
LBP hazards, compared with 19 percent ((4%) of households in the
$30,000/year or above income level.

Government-supplied housing may have fewer lead-based paint hazards than
housing without Government support.  An estimated 17 percent of
Government-supported housing had significant lead-based paint hazards,
compared to 26 percent of housing without Government support.

Table 3.2 presents the number of homes with significant LBP hazards by
location in the building–either interior or exterior, or both.

Table 3.2	Prevalence of Significant Lead-Based Paint (LBP) Hazards by
Location in the Building

HUD Lead Safe Housing Rule:  Significant LBP Hazards

LBP Hazard Location	Number of HUsa (000)	Percent of HUsb	HUs in Sample

	Estimate	Lower

95% CIc	Upper

95% CI	Percent	Lower

95% CI	Upper

95% CI

	Interior only	8,823	6,439	11,207	9%	7%	12%	63

Both Interior and Exterior	8,869	6,634	11,104	9%	7%	12%	99

Exterior only	6,334	4,741	7,928	7%	5%	8%	48

Anywhere	24,026	21,307	26,746	25%	22%	28%	210

No Significant LBP Hazard	71,661	68,498	74,825	75%	72%	78%	621

Total HUs	95,688

	100%

	831

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b All percentages are calculated with total housing units (95,688) as
the denominator.  Percentages may not total 100% due to rounding.

c CI = 95% confidence interval for the estimated number or percent.

Table 3.3 presents data for the presence of significant LBP hazards in
homes by type of hazard, for all homes in the National Survey’s target
population and for homes with one or more children under the age of 6
years.  The percentages for each “All HUs” row of Table 3.3 show the
percent of all HUs with the component of significant LBP hazard, while
the percentages in each “HUs w/Child Under 6” row of Table 3.3 show
the percent of all HUs with a child under age 6 with that component of
significant LBP hazard.

Table 3.4 breaks out the data in Table 3.3 for all HU’s by
construction year.  All three components of significant lead-based paint
hazards show the same pattern of substantially greater prevalence of
hazards among older housing units, especially pre-1940 homes.  For all
housing unit ages, soil lead hazards have the lowest prevalence.

Table 3.3	Prevalence of Significant Lead-Based Paint (LBP) Hazards in
Housing Units with a Child Under 6 Years of Age by Type of Hazard

HUD Lead Safe Housing Rule: Significant LBP Hazards

Type of Hazard	Number of HUsa (000)	Percent of HUsb (%)

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

Significantly Deteriorated Lead Based Paint

All HUs	13,634	10,928	16,341	14%	11%	17%

HUs w/ Child Under 6	2,519	1,715	3,324	15%	10%	20%

Interior Lead Dust

All HUs	15,468	12,982	17,954	16%	14%	19%

HUs w/ Child Under 6	2,634	1,587	3,681	16%	10%	22%

Lead Contaminated Soil

All HUs	6,460	3,122	9,799	7%	3%	10%

HUs w/ Child Under 6	1,511	0	3,108	9%	0%	19%

Any LBP Hazard

All HUs	24,026	21,306	26,746	25%	22%	28%

HUs w/ Child Under 6	4,155	2,948	5,363	25%	18%	33%

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b Percentages are calculated with total housing units (95,688) or with
housing units with a child under age 6 (16,402) as the denominator, as
applicable.

c CI = 95% confidence interval for the estimated number or percent.

Table 3.4 	Prevalence of Significant Lead-Based Paint (LBP) Hazards in
Housing Units by Type of Hazard and Housing Unit Age

HUD Lead Safe Housing Rule: Significant LBP Hazards

Type of Hazard	Number of HUsa (000)	Percent of HUsb (%)

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

Significantly Deteriorated Lead Based Paint

Built 1978-1998	83	0	240	0%	0%	1%

Built 1960-1977	610	91	1,128	2%	0%	4%

Built 1940-1959	5,190	3,367	7,013	25%	16%	34%

Built Before 1940	7,752	6,029	9,475	44%	34%	54%

Interior Lead Dust

Built 1978-1998	959	98	1,821	3%	0%	6%

Built 1960-1977	1,943	1,173	2,714	7%	4%	10%

Built 1940-1959	4,665	3,181	6,150	23%	15%	30%

Built Before 1940	7,735	5,982	9,489	44%	34%	54%

Lead Contaminated Soil

Built 1978-1998	0	0	0	0%	0%	0%

Built 1960-1977	130	0	263	0%	0%	1%

Built 1940-1959	2,562	0	3,830	12%	0%	19%

Built Before 1940	3,867	254	4,741	22%	1%	27%

Any LBP Hazard

Built 1978-1998	1,042	169	1,914	3%	1%	6%

Built 1960-1977	2,340	1,445	3,235	8%	5%	12%

Built 1940-1959	8,826	6,364	10,932	43%	31%	53%

Built Before 1940	11,818	9,688	13,591	68%	55%	78%

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b Percentages are calculated with housing units built in that time
period as the denominator.

c CI = 95% confidence interval for the estimated number or percent.

3.3	Prevalence of Lead-Related Occupations or Hobbies

Table 3.5 presents the number and percent of all U.S. households in
which at least one occupant engages in a lead-related occupation or
hobby.  Data for home cleanliness and clutter categories are also
presented.  Table 3.6 presents the same data for homes with significant
LBP hazards.  As described below, all of these estimates are likely to
overstate the number of households that may have contributions to lead
in dust from these behaviors.

An estimated 24 percent ((3%) of households report that at least one
occupant engages in a listed lead-related occupation, e.g., construction
or renovation work, lead industry work, automotive repair or radiator
work, or firing range work.  This may be elevated above the actual
estimate of people who may bring lead home due to the fact that many
people in the construction business only work with new construction or
in projects which that do not involve disturbing LBP, dust-lead hazards
or soi6l-lead hazards.  Similarly, a person working in a lead-related
industry may have an administrative position and have no lead exposure
at all.

An estimated 41 percent ((5%) report that at least one occupant engages
in a potentially lead-related hobby at home, e.g., making bullets or
sinkers, furniture or home renovation, stained glass, pottery, or making
jewelry.  Among homes with significant LBP hazards, 31 percent ((8%)
report that at least one occupant engages in a potentially lead-related
hobby.  These may be high estimates of the number of homes where lead
dust is actually generated since some of these people may generally or
always use lead-free materials in their hobbies.

Home cleanliness has been associated with lead dust levels.  About half
of all homes were found to be clean (59%) and organized (43%), using the
criteria in this survey.  Homes with significant LBP hazards in their
interiors were generally somewhat less clean and organized; the
percentage of clean homes is 36%, 23% lower than the general population,
and the percentage of organized homes is 28%, 15% lower than the general
population.

Table 3.5	Prevalence of Housing Units with Selected Lead-Related
Characteristics

Lead Related Behavior	Number of HUs (000)a	Percent of HUs (%)b	HUs in
Sample

	Estimatec	Lower

95% CId	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Lead Related Occupation	22,673	19,732	25,615	24%	21%	27%	203

Lead Related Hobby	39,281	35,020	43,543	41%	36%	46%	347

Cleanliness

	House Appears Clean	56,058	51,887	60,228	59%	54%	63%	462

Some Evidence of Cleaning	25,347	21,417	29,277	26%	22%	31%	237

No Evidence of Cleaning	9,646	7,577	11,714	10%	8%	12%	86

Clutter

	Clutter Organized	41,158	37,650	44,666	43%	40%	46%	347

Average Amount of Clutter	38,601	35,663	41,539	40%	37%	43%	336

No Organization	11,045	8,859	13,231	12%	9%	14%	100

Total HUs	95,688

831

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b All percentages are calculated with total housing units (95,688) as
the denominator.  Percentages may not total 100% due to rounding.

c Estimates are based on the full weighted sample.

d CI = 95% confidence interval for the estimated number or percent.

Table 3.6	Prevalence of Selected Lead-Related Characteristics in Homes
with Significant Interior LBP Hazards

Lead Related Behavior	Number of HUs (000)a	Percent of HUs (%)b	HUs in
Sample

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Lead Related Occupation	4,990	3,195	6,785	28%	18%	38%	45

Lead Related Hobby	5,485	4,043	6,926	31%	23%	39%	57

Cleanliness

	House Appears Clean	6,360	4,030	8,691	36%	23%	49%	60

Some Evidence of Cleaning	6,757	5,221	8,294	38%	30%	47%	63

No Evidence of Cleaning	3,258	1,646	4,870	18%	9%	28%	28

Clutter

	Clutter Organized	5,041	3,052	7,029	28%	17%	40%	44

Average Amount of Clutter	7,899	6,386	9,412	45%	36%	53%	77

No Organization	3,436	1,911	4,961	19%	11%	28%	30

Total HUs	17,692

162

a “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b All percentages are calculated with total housing units with
significant interior LBP hazard (18,827) as the denominator.
Percentages may not total 100% due to rounding.

c CI = 95% confidence interval for the estimated number or percent.

4.  LEAD-BASED PAINT (LBP) IN HOUSING

Chapter 4 presents estimates of the prevalence, location, and amount of
lead-based paint (LBP) and deteriorated LBP in housing, including paint
lead loadings in housing.  Relevant estimates are compared with the
findings of the 1990 LBP Survey.

Under the HUD Lead Safe Housing Rule (24 CFR 35 Subparts B-R), LBP is
defined as any paint or other surface coating (e.g., varnish, lacquer,
or wall-paper over paint) that contains lead equal to or greater than
1.0 mg/cm2.  The estimates for deteriorated LBP and significantly
deteriorated LBP are presented in Section 4.2.  Under the Lead Safe
Housing Rule, LBP is considered to be deteriorated if there is any
deterioration.  It is considered to be significantly deteriorated if the
deterioration exceeds the de minimis thresholds given in the definition
of a significant LBP hazard presented in Chapter 3.

4.1	Prevalence of Lead-Based Paint

An estimated 38 million ((3 million) or 40 percent ((4%) of housing
units (HUs) in the United States have LBP on either the interior or
exterior painted surfaces, or both.  Figures 4.1 and 4.2 present the
percentage of housing units with LBP by selected characteristics,
including presence of children under age 6, geographic region, housing
unit type, tenure, race, and year of construction.  Table 4.1 presents
the number and percentage of housing units with LBP by a much wider
range of housing unit and household characteristics.

The data suggest that homes in northeastern and midwestern states are
more likely to have LBP than homes in southern or western states.  An
estimated 55 percent and 53 percent of homes in the Northeast and
Midwest have LBP, while the estimates are 27 percent and 32 percent for
homes in the South and West, respectively.  This finding can be
explained by the fact that the housing stock in the Northeast and
Midwest is older.

Figure 4.1	Prevalence of LBP by Selected Housing Unit Characteristics

Figure 4.2	Prevalence of HUs with LBP by Construction Year & Presence of
Children <6

As expected, older homes are more likely to have LBP than newer homes.
An estimated 24 percent (+6%) of homes built between 1960 and 1977 have
LBP, but the percentage increases to 69 percent (+9%) for homes built
between 1940 and 1959, and to 87 percent (+5%) for homes built before
1940.  Table 4.1 indicates that 5 to 8 percent of homes built after 1977
have LBP.  This estimate is likely to be somewhat high, for two reasons.
 First, housing unit age is based on the residents’ reports.  Some
residents, especially renters, may have reported their homes as being
newer than they actually are. There were a few homes in the survey in
which an examination of all of the data collected from a home presented
a picture that suggested that the home may be older than reported by the
respondent.  Even so, in no case was the respondent’s reported age
overridden in the analyses.  Second, most of the homes in the sample
built after 1977 that had LBP had only one or two components measured
with LBP.  In approximately one-third of these homes, the substrate of
the one painted component in the home may have interfered with the
reading (these included painted metal, ceramic, or stone substrates
which may contain lead, but paint was not scraped to measure bare
substrate for this purpose).

Table 4.1	Prevalence of Lead-Based Paint (LBP) by Selected Housing Unit
(HU)

Characteristics

HU Characteristic	All HUs

(000)	Number of HUs with LBP (000)	Percent of HUs with LBP (%)a	HUs in
Sample

Estimate	Lower

95% CIb	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Total Housing Unitsc	95,688	37,897	34,521	41,272	40%	36%	43%	831

Region:

Northeast	19,290	10,600	8,306	12,895	55%	46%	64%	155

Midwest	22,083	11,748	10,546	12,950	53%	48%	59%	196

South	35,474	9,607	7,762	11,451	27%	22%	32%	277

West	18,841	5,942	4,747	7,137	32%	25%	38%	203

Construction Year:

1989-1998	10,378	514	-	1,444	5%	0%	14%	61

1978-1988	19,397	1,517	549	2,485	8%	3%	13%	159

1960-1977	27,874	6,577	4,875	8,280	24%	18%	30%	267

1940-1959	20,564	14,171	12,203	16,139	69%	60%	77%	186

Before 1940	17,476	15,117	13,532	16,702	87%	82%	91%	158

Region by Construction Year:

Northeast

HUs built 1978-1998	4,358	76	0	225	2%	0%	5%	30

HUs built 1960-1977	3,794	1,478	348	2,609	39%	9%	69%	31

HUs built 1940-1959	4,221	3,089	2,179	3,999	73%	52%	95%	35

HUs built before 1940	6,917	5,957	5,187	6,728	86%	75%	97%	59

Midwest

HUs built 1978-1998	4,801	533	0	1,134	11%	0%	24%	41

HUs built 1960-1977	6,283	1,771	872	2,670	28%	14%	42%	55

HUs built 1940-1959	5,899	4,785	4,011	5,559	81%	68%	94%	47

HUs built before 1940	5,101	4,658	3,888	5,429	91%	76%	100%	53

South

HUs built 1978-1998	14,447	1,197	0	2,436	8%	0%	17%	95

HUs built 1960-1977	11,261	1,914	1,216	2,612	17%	11%	23%	96

HUs built 1940-1959	6,320	3,431	2,329	4,532	54%	37%	72%	57

HUs built before 1940	3,445	3,065	2,676	3,453	89%	78%	100%	29

West

HUs built 1978-1998	6,169	225	0	473	4%	0%	8%	54

HUs built 1960-1977	6,536	1,414	816	2,011	22%	12%	31%	85

HUs built 1940-1959	4,124	2,866	1,715	4,017	69%	42%	97%	47

HUs built before 1940	2,013	1,437	376	2,498	71%	19%	100%	17

Urbanization:

MSA equal or above 2

  million population	26,814	9,681	7,550	11,812	36%	30%	42%	276

MSA below 2 million

  Population	45,753	17,390	14,026	20,754	38%	32%	44%	417

Non-MSA	23,121	10,826	7,458	14,193	47%	35%	59%	138

Table 4.1	Prevalence of Lead-Based Paint (LBP) by Selected Housing Unit
(HU)

Characteristics (continued)

HU Characteristic	All HUs

(000)	Number of HUs with LBP (000)	Percent of HUs with LBP (%)a	HUs in
Sample

Estimate	Lower

95% CIb	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	One or More Children Under Age 6:

All HU Ages	16,402	5,328	4,048	6,609 	32%	26%	39%	184

HUs built 1978-1998	5,847	202 	0	436 	3%	0%	7%	56

HUs built 1960-1977	5,098 	876 	416 	1,337 	17%	8%	26%	61

HUs built 1940-1959	3,055 	1,997 	1,341 	2,654 	65%	44%	87%	40

HUs built before 1940	2,401 	2,253 	1,426 	3,079 	94%	59%	100%	27

Housing Unit Type:

Single family	82,651	34,081	30,874	37,289	41%	37%	45%	705

Multi-family	13,037	3,815	2,470	5,160	29%	20%	39%	126

Tenure:

Owner-occupied	66,232	25,172	22,400	27,943	38%	35%	41%	539

Renter-occupied	29,074	12,409	9,538	15,281	43%	35%	50%	289

Refusal/Don’t Knowd	381

	3

Household Income:

Less than $30,000/year	33,830	15,007	11,604	18,411	44%	37%	52%	309

Equal to or more than

  $30,000/year	56,111	20,815	17,745	23,885	37%	32%	42%	482

Refusal/Don’t Know	5,747

	40

One or More Children Under Age 6:

All Income Categories	16,402	5,328	4,048	6,609	32%	26%	39%	184

	Less than $30,000/year	4,791	1,375	784	1,965	29%	16%	41%	61

	Equal to or more than

	  $30,000/year	11,236	3,820	2,579	5,061	34%	23%	45%	117

	Refusal/Don’t Know	375

	6

Government Support:

Government support	4,809	1,741	678	2,805	36%	16%	56%	54

No government support	86,070	33,871	30,681	37,062	39%	36%	43%	733

Refusal/Don’t Know	4,809

	44

Poverty by Urbanization:

MSA equal or above 2

  Million population

In poverty	2,962	1,205	735	1,674	41%	25%	57%	35

Not in poverty	22,005	7,758	5,957	9,559	35%	27%	43%	226

MSA below 2 million

  Population

In poverty	6,996	3,795	2,248	5,341	54%	32%	76%	75

Not in poverty	35,786	12,455	9,722	15,188	35%	27%	42%	323

Non-MSA

In poverty	3,264	1,362	310	2,414	42%	9%	74%	27

Not in poverty	18,544	8,684	5,071	12,297	47%	27%	66%	102

Refusal/Don’t Know if in

  Poverty	6,131

	43

Table 4.1	Prevalence of Lead-Based Paint (LBP) by Selected Housing Unit
(HU)

Characteristics (continued)

HU Characteristic	All HUs

(000)	Number of HUs with LBP (000)	Percent of HUs with LBP (%)a	HUs in
Sample

Estimate	Lower

95% CIb	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Race:

White	77,005	30945	28,037	33853	40%	37%	44%	622

African American	10,365	4,228	2,767	5,689	41%	30%	52%	116

Othere	6,571	1,913	1,015	2,811	29%	17%	41%	77

Unknown	1,746

	16

Ethnicity:

Hispanic/Latino	7,434	3,329	2,044	4,614	45%	31%	59%	86

Not Hispanic/Latino	87,008	33,830	30,436	37,223	39%	35%	42%	736

Refusal/Don’t Know	1,246

	9

a All percentages are calculated with the “all HUs” on the left most
column of each row as the denominator.

b CI = 95% confidence interval for the estimated number or percent.

c “Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

d Refusals and “don’t know” responses by survey respondents.

e “Other” race includes Asian, American Indian or Alaskan Native,
Native Hawaiian or other Pacific Islander, and more than one race.

An estimated 5.3 million ((1.3 million) or 32 percent (( 6%) of homes
with children under the age of 6 years have lead-based paint, although
children are eligible to live in all of the estimated 38 million homes
with lead-based paint.  Homes with children under age 6 showed the same
relationship between HU age and the presence of LBP as do all homes.

The differences among LBP prevalence by urbanization, single family
versus multi-family housing, occupant status, household income, race,
ethnicity, and poverty crossed with urbanization do not appear to be
significant in that the confidence intervals overlap.  Likewise, there
were no differences in LBP prevalence when one or more children under
age 6 was crossed by construction year.

Figure 4.3 and Table 4.2 present the number of homes with LBP by
location in the building – either interior or exterior, or both.
About one-half of homes with lead-based paint have it on both interior
and exterior surfaces (21% of all homes, or 53% of homes with LBP
anywhere in the building).

Table 4.2	Prevalence of Lead-Based Paint (LBP) by Location in the
Building

LBP Location	Number of HUsa with LBP (000)	Percent of HUs with LBP (%)b
HUs in Sample

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

	Interior Only	8,609	6,102	11,116	9%	6%	12%	77

Both Interior and Exterior	20,260	17,961	22,558	21%	19%	24%	181

Exterior Only	9,028	6,535 	11,521	9%	7%	12%	80

Subtotal – LBP anywhere

  in Building	37,897	34,521	41,272	40%	36%	43%	338

No LBP in Building	57,791 	54,624	60,959	60%	57%	64%	493

Total HUs	95,688

	100%

	831

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	All percentages are calculated with total housing units (95,688) as
the denominator.  Percentages may not total 100% due to rounding.

c	CI = 95% confidence interval for the estimated number or percent.

Figure 4.3	Prevalence of Lead Based Paint (LBP) by Location in the
Building

4.2	Prevalence of Deteriorated Lead-Based Paint

Although there are many homes with LBP, the condition of the paint is
important in determining whether a hazard exists.  Except during
renovations, maintenance, or other activities that could disturb it,
intact lead-based paint is believed to pose little immediate risk to
occupants.  However, significantly deteriorated lead-based paint may
present an immediate danger to occupants, especially to young children.
Table 4.3 presents the number and percentage of HUs with deteriorated
LBP and significantly deteriorated LBP by location in the building -
either interior or exterior, or both.

Table 4.3	Prevalence of Deteriorated and Significantly Deteriorated
Lead-Based Paint (LBP) by Location in the Building

Deteriorated LBP

Location	Number of HUsa with Deteriorated LBP (000)	Percentb of HUs with
Deteriorated LBP(%)	HUs in Sample

	Estimate	Lower 95% CIc	Upper 95% CI	Estimate	Lower 95% CI	Upper 95% CI

	Interior Only	4,180	2,851	5,509	4%	3%	6%	39

Both Interior and Exterior	6,236	4,661	7,811	7%	5%	8%	62

Exterior Only	7,009	4,922	9,097	7%	5%	10%	61

Total with Deteriorated LBP	17,425	14,816	19,735	18%	15%	21%	162

No Deteriorated LBP	78,263	75,953	80,572	82%	79%	84%	669

TOTAL	95,688

	100%

	831

Significantly Deteriorated LBP

Location	Number of HUsa with Significant Deteriorated LBP (000)	Percentb
of HUs with Significant Deteriorated LBP(%)	HUs in Sample

	Estimate	Lower 95% CIc	Upper 95% CI	Estimate	Lower 95% CI	Upper 95% CI

	Interior Only	2,629	1,692	3,566	3%	2%	4%	28

Both Interior and Exterior	3,487	2,132	4,842	4%	2%	5%	34

Exterior Only	7,518	5,357	9,679	8%	6%	10%	65

Total with Significantly Deteriorated LBP	13,634	10,928	16,341	14%	11%
17%	127

No Significantly Deteriorated LBP	82,053	79,347	84,760	86%	83%	89%	704

TOTAL	95,688

	100%

	831

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	Percentages are calculated with total housing units (95,688) as the
denominator.  Percentages may not total 100% due to rounding.

c	CI = 95% confidence interval for the estimated number or percent.

An estimated 17 million ((2 million) or 18 percent ((3%) of housing
units in the United States have deteriorated LBP.  The deteriorated LBP
is only on the exterior for approximately 40 percent of the homes with
deteriorated LBP.  An estimated 14 million ((3 million) or 14 percent
((3%) of housing units in the United States have significantly
deteriorated LBP.  Roughly 55 percent of these homes have significant
deterioration only on exterior surfaces.  Twenty percent of these homes
have the significantly deteriorated LBP only on interior surfaces.

Table 4.4 presents the number and percentage of housing units with
deteriorated and significantly deteriorated LBP by construction year.
The data suggest that older homes are more likely to have deteriorated
LBP than newer homes.  Only 3% of homes built between 1960 and 1977 have
deteriorated LBP, but the percentage increases to 32% for homes built
between 1940 and 1959, and to 56% for homes built before 1940.  Only 2%
of homes built between 1960 and 1977 have significantly deteriorated
LBP, but the percentage increases to 25% for homes built between 1940
and 1959, and to 44% for homes built before 1940.

Table 4.4	Distribution of Housing Units (HUs) with Deteriorated and
Significantly Deteriorated Lead-Based Paint (LBP) by Construction Year

Deteriorated LBP

Construction Year	Total HUs (000)b	Number of HUs with

Deteriorated LBP (000)	Percent of HUs with

Deteriorated LBP (%)a

Estimate	Lower 95% CIc	Upper 95% CI	Estimate	Lower 95% CI	Upper 95% CI

1978-1998	29,774	139	0	330	0%	0%	1%

1960-1977	27,874	910	235	1,586	3%	1%	6%

1940-1959	20,564	6,510	4,603	8,418	32%	22%	41%

Before 1940	17,476	9,866	8,111	11,620	56%	46%	66%

Total HUs	95,688	17,425	15,222	19,628	18%	16%	21%

Significantly Deteriorated LBP

Construction Year	Total HUs (000)b	No. of HUs with Significantly
Deteriorated LBP (000)	Percent of HUs with Significantly Deteriorated
LBP (%)a

Estimate	Lower 95% CIc	Upper 95% CI	Estimate	Lower 95% CI	Upper 95% CI

1978-1998	29,774	83	0	238	0%	0%	1%

1960-1977	27,874	610	97	1,122	2%	0%	4%

1940-1959	20,564	5,190	3,387	6,993	25%	16%	34%

Before 1940	17,476	7,752	6,048	9,456	44%	35%	54%

Total HUs	95,688	13,635	9,893	16,582	14%	10%	17%

a	Percentages may not total 100% due to rounding.

b	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

c	CI = 95% confidence interval for the estimated number or percent.

Figure 4.4 is a bar chart that summarizes the above survey data on
deteriorated and significantly deteriorated LBP by construction year.
It graphically displays the downward trends in the prevalence of LBP in
homes and of damaged LBP in homes.

Figure 4.4.  Presence and Condition of LBP by Construction Year

4.3	Paint Lead Loadings in Housing

Table 4.5 presents the distribution of the highest lead paint loading by
location in the building for selected thresholds: 0.3, 0.6, 0.8, 1.0,
1.3, 4.0, and 10.0 mg/cm2.  By definition, paint with less than 1.0
mg/cm2 is not LBP; thus, the first four categories represent paint that
is considered not to be LBP.  The majority of the surfaces did not
contain lead-based paint: in 70 percent of HUs the highest interior
readings, and in 69 percent of HUs the highest exterior readings, were
below 1.0 mg/cm2. Fourteen percent of HUs had at least one paint sample
with 10 mg/cm2 or more of lead-based paint.

Table 4.5	Distribution of Paint Lead Loading by Location in the Building

Maximum Paint	Interior (% HUs)a	Exterior (% HUs)	Anywhere (% HUs)

Lead Loading in HUc	Estimate	Lower

95% CIb	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

GT 0 mg/cm2 	100%	100%	100%	100%

	100%

GE 0.3 mg/cm2	51%	47%	55%	42%	39%	46%	62%	58%	67%

GE 0.6 mg/cm2	37%	34%	39%	35%	32%	38%	47%	44%	50%

GE 0.8 mg/cm2	31%	29%	34%	32%	29%	36%	42%	39%	45%

GE 1.0 mg/cm2	30%	27%	33%	31%	27%	34%	40%	36%	43%

GE 1.3 mg/cm2	26%	24%	29%	29%	26%	33%	36%	33%	40%

GE 4.0 mg/cm2	17%	14%	20%	18%	15%	22%	24%	20%	27%

GE 10.0 mg/cm2	9%	7%	12%	10%	8%	13%	14%	11%	17%

TOTAL HUs	100%

	100%

	100%

a	All percentages are calculated with total housing units (95,688) as
the denominator.  “Housing units” include permanently occupied,
noninstitutional housing units in which children are permitted to live.

b	CI = 95% confidence interval for the estimated number or percent.

c	GT equals “greater than.”  GE equals “greater than or equal
to.”

Table 4.6 presents the distribution of paint lead loadings by location
in the building and construction year for the selected thresholds.  This
clearly demonstrates the effectiveness of the reduction from 1940 to
1980 in the amount of lead added to commercial residential paint.  An
estimated 87 percent of housing reported as built before 1940 had at
least one paint lead measurement somewhere in the house at 1.0 mg/cm2,
or above.  This decreased to 24 percent of housing reported as built
between 1960 and 1977, and to 7 percent of housing reported as built
since 1978.  The same pattern holds for very high lead levels, with 55
percent of pre-1940 homes having some lead above 10 mg/cm2 but only 1
percent for post-1977 housing.

Table 4.6	Distribution of Paint Lead Loading by Location in the
Building and Construction Year

Percent of HUs with LBPa,b

Largest Paint Lead Loading in the Housing Unit	Year of Construction

	1978-1998	1960-1977	1940-1959	Before 1940	Subtotal

Interior

GT 0 mg/cm2 	100%	100%	100%	100%	100%

GE 0.3 mg/cm2	23%	39%	77%	91%	51%

GE 0.6 mg/cm2	9%	21%	59%	83%	37%

GE 0.8 mg/cm2	6%	16%	48%	80%	31%

GE 1.0 mg/cm2	4%	16%	46%	79%	30%

GE 1.3 mg/cm2	3%	12%	41%	72%	26%

GE 4.0 mg/cm2	1%	6%	19%	60%	17%

GE 10.0 mg/cm2	1%	2%	7%	38%	9%

Exterior

GT 0 mg/cm2 	100%	100%	100%	100%	100%

GE 0.3 mg/cm2	11%	31%	69%	81%	42%

GE 0.6 mg/cm2	7%	18%	64%	76%	35%

GE 0.8 mg/cm2	4%	16%	61%	73%	32%

GE 1.0 mg/cm2	3%	13%	59%	72%	31%

GE 1.3 mg/cm2	3%	11%	56%	71%	29%

GE 4.0 mg/cm2	0%	6%	28%	56%	18%

GE 10.0 mg/cm2	0%	2%	10%	41%	10%

Anywhere in Building

GT 0 mg/cm2 	100%	100%	100%	100%	100%

GE 0.3 mg/cm2	30%	57%	89%	95%	62%

GE 0.6 mg/cm2	15%	31%	80%	89%	47%

GE 0.8 mg/cm2	10%	26%	70%	88%	42%

GE 1.0 mg/cm2	7%	24%	69%	87%	40%

GE 1.3 mg/cm2	5%	18%	65%	84%	36%

GE 4.0 mg/cm2	1%	10%	34%	73%	24%

GE 10.0 mg/cm2	1%	3%	14%	55%	14%

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	GT equals “greater than.”  GE equals “greater than or equal
to.”

Tables 4.7 and 4.8 present selected parameters of the distributions of
paint lead loadings by interior and exterior component types.  Tables
4.7 and 4.8 do not include the geometric means and standard deviations
because of the large number of zero XRF readings.  All of the
distributions in Tables 4.7 and 4.8 are right-skewed and cannot be
fitted by normal distributions.  A better model would be the lognormal
distribution.  Appendix C presents a discussion of fitting models to
these data.

Table 4.7	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by Interior Component Types

	Walls, Floors, Ceilings	Windows	Doors	Trim	Other

	mg/cm2	mg/cm2	mg/cm2	mg/cm2	mg/cm2

Arithmetic Mean	0.2	0.9	0.5	0.5	0.4

Arithmetic Standard Deviation	1.5	3.4	2.5	2.3	2.6

25th Percentile	0.0	0.0	0.0	0.0	0.0

Median	0.0	0.0	0.0	0.0	0.0

75th  Percentile	0.0	0.1	0.0	0.0	0.0

90th Percentile	0.1	1.3	0.4	0.2	0.2

95th Percentile	0.3	6.0	1.9	1.4	0.5

Number of Readings	14,876	5,513	4,596	2,578	2,686

Table 4.8	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by Exterior Component Types

	Walls	Windows	Doors	Trim	Porch	Other

	mg/cm2	mg/cm2	mg/cm2	mg/cm2	mg/cm2	mg/cm2

Arithmetic Mean	0.9	2.5	1.2	1.1	1.1	1.6

Arithmetic Standard Deviation	3.4	6.2	4.4	4.5	3.9	5.1

25th Percentile	0.0	0.0	0.0	0.0	0.0	0.0

Median	0.0	0.0	0.0	0.0	0.0	0.0

75th  Percentile	0.1	1.7	0.1	0.1	0.1	0.3

90th Percentile	1.9	7.7	2.4	1.8	2.2	3.3

95th Percentile	4.8	15.3	7.4	5.4	7.8	10.7

Number of Readings	2,008	781	1,398	446	698	250

Table 4.9 summarizes the data on LBP by component type from a different
perspective; it presents the percentage of components with LBP by
component type and housing unit age.  Table 4.9 shows the expected
trends and differences:  exterior components are more likely to be
leaded than interior components; interior walls are least likely to have
LBP; and older homes have more LBP than newer homes.

Table 4.9	Percentage of Components with Lead-Based Paint by Component
Type and HU Age

Component Type	Year of Construction

	All Years	1978-1998	1960-1977	1940-1959	Before 1940

Interior	Walls, Floors Ceilings	2%	0%	1%	2%	7%

	Windows	9%	1%	2%	6%	21%

	Doors	7%	0%	1%	7%	22%

	Trim	5%	0%	2%	4%	15%

	Other	4%	0%	1%	2%	12%

	All Components	30%	4%	16%	46%	79%

Exterior	Walls	14%	0%	9%	18%	34%

	Windows	25%	0%	12%	30%	41%

	Doors	15%	2%	5%	29%	33%

	Trim	11%	3%	8%	16%	24%

	Porch	15%	1%	7%	25%	28%

	Other	18%	0%	8%	37%	37%

	All Components	31%	3%	13%	59%	72%

Table 4.10 presents selected parameters of the distributions of paint
lead loading by interior rooms and for all exterior surfaces. Paint lead
loadings are higher on exterior surfaces than on interior surfaces.
Differences between average paint lead loadings in interior rooms are
small compared to differences between component types within rooms (see
Table 4.7).

Table 4.10	Estimated Empirical Distribution Parameters of Paint Lead
Loadings by Room Type

	Kitchen	Living Room	Bed Room	Other Room	Exterior

	mg/cm2	mg/cm2	mg/cm2	mg/cm2	mg/cm2

Arithmetic Mean	0.5	0.4	0.4	0.4	1.3

Arithmetic Standard Deviation	2.3	2.3	2.3	2.3	4.4

25th Percentile	0	0	0	0	0

Median	0	0	0	0	0

75th  Percentile	0.1	0	0	0	0.2

90th Percentile	0.4	0.2	0.2	0.2	2.7

95th Percentile	1.7	0.8	1	0.8	7.8

Number of Readings	7127	7375	8053	7387	5581

4.4	Comparison of Prevalence of Lead-Based Paint (LBP) to the 1990 LBP
Survey

Table 4.11 compares the prevalence of LBP and deteriorated LBP found in
the NSLAH (restricted to pre-1980 construction) with the prevalence
found in the 1990 LBP Survey, which was similarly restricted.  The NSLAH
shows fewer total homes built before 1980.  This is partly due to the
fact that housing where children could not live was excluded from the
current survey.  There has also been a loss of homes built before 1980
due to demolition.

Table 4.11	Comparison of the Prevalence of Lead-Based Paint1 to the 1990
LBP Survey

	1990 LBP Survey	Current NSLAH

(Pre-1980 HUs)

	Number

(000)	Percent

(%)	Number

(000)	Percent

(%)

Total HUs Built Before 1980	77,177	100%	68,756	100%

	HUs with LBP	64,059	83%	34,195	50%

	Interior LBP	48,986	63%	26,184	38%

	Exterior LBP	56,495	73%	27,373	40%

HUs with Deteriorated LBPa	14,354	19%	14,962	22%

	Interior Deteriorated LBP	5,596	7%	7,281	11%

	Exterior Deteriorated LBP	9,657	13%	11,784	17%

a	Deteriorated LBP is defined in the 1995 HUD Guidelines (Guidelines for
the Evaluation and Control of Lead-Based Paint Hazards in Housing, HUD
1539-LBP, Washington, D.C.) for the NSLAH, and as 5 square feet or more
of deteriorated LBP for the 1990 survey.

A lower percentage of pre-1980 homes were found with LBP during the
current NSLAH (50% versus 83% found in 1990).  This was not unexpected
because there has been renovation, remodeling, demolition, and paint
removal activities in the intervening years.

The number of homes with LBP was expected to decrease between 1990 and
1999, primarily due to demolition, renovation and remodeling of older
homes.  For homes built around the same time, the percentage of homes
with LBP was also expected to decrease between 1990 and 1999, primarily
due to renovation and remodeling of older homes.  However, the
difference between the 1990 and 1999 survey estimates of the number and
percentage of homes with LBP is greater than might be expected from
these sources.  Factors that might explain the differences include:

Demolition.  Demolition of older homes reduces the number of homes with
LBP over time.

Renovation, Remodeling, and Remediation.  Removal of surfaces with LBP
during renovation and remodeling reduces both the number and percentage
of homes with LBP.  Covering (encapsulating) surfaces with LBP reduces
the quantity of lead directly accessible to occupants and reduces the
XRF reading on the surface.  The lower XRF readings result in fewer
homes classified as having LBP.  Although additional coats of paint are
expected to reduce XRF readings, the effect of painting is expected to
be small.

XRF Models.  XRF measurements from the 1999 survey are more precise than
those from the 1990 survey.  The less precise XRF instrument used in the
1990 survey was more likely to misclassify a surface as having LBP and
thus increases the estimated number of surfaces with LBP.

XRF Calibration Procedures.  The calibration of the XRF instrument used
for the 1990 survey was checked at paint loadings of 0.6 and 3.0 mg lead
per sq.cm.  The 1990 XRF readings were recalibrated based on these
checks.  The calibration of the XRF instrument used for the 1999 survey
was checked at paint loadings of 0.0 and 1.0 mg lead per sq.cm.  The
difference in the calibration procedures and the assumptions required
for the re-calibration of the 1990 XRF readings have an unknown effect
of the estimated number of homes with LBP.

Sample Design.  The two surveys used slightly different criteria and
sampling methods for selecting the sampled homes.  The primary
difference being that the 1999 survey excluded homes where children were
excluded, some of which may have been included in the 1990 survey.

Within-home Data Collection Procedures.  The two surveys had different
criteria and procedures for within-home data collection.  The 1999
survey collected measurements in more rooms within the sampled homes
than the 1990 survey (4 to 6 rooms vs. 2 rooms).  Within the sampled
rooms the 1999 survey also collected more measurements.  The larger
number of measurements in the 1999 survey would tend to increase the
number of homes classified as having LBP, other factors being equal,
contrary to the observed decrease.

Approximately the same percentage of pre-1980 homes with LBP had
deteriorated LBP in both surveys (22% versus 19% found in 1990).  The
slight increase in the percentage of homes with deteriorated LBP was
expected, because these homes are now nine years older.  In addition,
the definitions of deteriorated LBP were different for the two studies.
In the 1990 LBP Survey, deteriorated interior LBP was defined as more
than 5 square feet of deteriorated interior lead-based paint, with a
similar definition for exterior lead-based paint.  Table 4.11 defines
deteriorated LBP for the NSLAH according to the 1995 Guidelines
(Guidelines for the Evaluation and Control of Lead-Based Paint Hazards
in Housing).  For these reasons, Table 4.11 does not attempt to present
comparisons with respect to significantly deteriorated LBP; the concepts
of deterioration above de minimis levels were different in 1990 and
1999.

4.5	Area of Lead-Based Paint in Housing

Table 4.12 presents estimates of the areas of surfaces with LBP by
architectural component type.  An estimated 7.4 billion square feet of
painted interior surfaces are covered with LBP.  This represents 2
percent of the area of painted interior surfaces in all homes.  Although
2 percent of paint on walls, floors, and ceilings is lead-based, the
area of these LBP-coated components accounts for 67 percent of all
interior surfaces with LBP. Conversely, paint on window and door system
components is more likely to contain LBP, but the total surface area of
LBP on these components is only 21 percent of the area of all interior
painted surfaces.

An estimated 29.2 billion square feet of painted exterior surfaces are
covered with LBP.  This represents 22 percent of the area of painted
exterior surfaces in all homes.  Wall siding accounts for most (67%) of
the surface area of LBP.

Although a large number of homes have LBP, most of them have relatively
small areas of LBP.  The average home with LBP has 259 square feet of
interior LBP and 996 square feet of exterior LBP.

Table 4.12	Area of LBP by Painted Component

Component	National Total Amount of LBP	Average Amount LBP Per Housing
Unit with LBP

	Millions of sq. ft.	Percent of All Paint on Component	(square feet)

INTERIOR:

	Wall, Floor, Ceiling	4,993	2%	173

Window	687	9%	24

Door	911	6%	32

Trim	499	5%	17

Cabinets, Chimney, Beams	388	2%	13

TOTAL	7,448	2%	259

EXTERIOR:

	Wall	26,706	18%	912

Window	365	28%	12

Door	446	14%	15

Trim	556	12%	19

Porch	1,086	21%	37

TOTAL	29,159	22%	996

5.  DUST LEAD IN HOUSING

Chapter 5 presents estimates of the prevalence of lead-contaminated dust
in housing, including the dust lead loadings and the association between
interior dust lead and exterior LBP condition.  No comparison is made
with the dust lead findings of the 1990 LBP Survey because the vacuum
technique employed in the earlier study is not comparable to the wipe
technique used in the NSLAH.

5.1	Prevalence of Dust Lead in Housing

Table 5.1 presents the prevalence of all homes and homes with one or
more children under 6 years of age with a dust lead hazard somewhere in
the home, as defined by the HUD Lead Safe Housing Rule (24 CFR 35
Subparts B-R).  The HUD Lead Safe Housing Rule defines a dust lead
hazard as greater than or equal to 40 µg/ft2 lead on floors or 250
µg/ft2 lead on window sills.  There is no longer a hazard level defined
for dust lead on window troughs.  The earlier HUD 1995 Guidelines
considered lead in dust to be a hazard when dust on floors had greater
than 100 µg/ft2 lead, dust on window sills had greater than 500 µg/ft2
lead, or dust on window troughs had greater than 800 µg/ft2 lead.  As
discussed in Section 3.1 a housing unit is considered to have a dust
lead hazard if a dust lead hazard exists at any of the sampled locations
in the housing unit.  In contrast, the EPA Lead Hazards Identification
Rule considers a housing unit to have a dust lead hazard if the average
of the samples exceeds the relevant

Using the HUD Lead Safe Housing Rule definition of dust lead hazard, an
estimated 16 percent (+2%) of all homes have a dust lead hazard
somewhere in the home, and 3 percent (+1%) of all homes have both a
child under 6 years of age and a dust lead hazard.

Figures 5.1 and 5.2 present the percentage of homes with dust lead
hazards by surface – floor and window sill – and by housing unit age
and household income.  The expected gradient with housing unit age is
seen in Figure 5.1.  Both figures show that window sills have the
greater prevalence of dust lead hazards.

Table 5.1	Prevalence of Housing Units with a Dust Lead Hazard Somewhere
in the Home

HU Categorya	Number of HUs (000)	Percent of HUs(%)b

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

HUs with Lead Dust Hazard 	15,468	12,982	17,954	16%	14%	19%

HUs with Children Under 6 Years and Lead Dust Hazard 	2,634	1,586	3,682
16%	11%	20%

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	All percentages are calculated with total housing units (95,688) or
HUs with resident children under age 6 (16,402) as the denominator.

c	CI = 95% confidence interval for the estimated number or percent.

Figure 5.1	Dust Lead Hazards by Construction Year

Figure 5.2	Dust Lead Hazards by Household Income

5.2	Dust Lead Loadings in Housing

Figures 5.3 and 5.4 present the distribution of maximum (within housing
unit) dust lead loadings on floors and window as histograms. Tables 5.2
and 5.3 present information on maximum and average dust loadings,
respectively, by surface.

Table 5.2 presents the distribution of maximum dust lead loadings by
surface (floor, window sill, and window trough) for all U.S. homes in
the target population, for selected threshold values.  As with Table
5.1, the estimates are based on the maximum dust lead loading in the
home for the particular surface.

Only an estimated 6 percent of all homes have maximum floor dust lead
loadings above the HUD Lead Safe Housing Rule standard of 40 µg/ft2.
More homes have a window sill lead dust hazard than have a floor dust
hazard.  An estimated 14 percent of all homes have sill dust lead
loadings above the HUD Lead Safe Housing Rule standard hazard of 250
µg/ft2.

Figure 5.3		Distribution of Maximum Floor Dust Lead Loadings

Figure 5.4		Distribution of Maximum Window Sill Dust Loadings

Table 5.2	Distribution of Maximum Dust Lead Loadings in Housing Units by
Surface

Maximum Dust Lead Loading in HU (µg/sq ft)	Number of HUs (000)a	Percent
of HUs (%)b

	Estimate	Lower

95% CId	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

Floors:c

LT LODe	38,369	34,302	42,436	40%	36%	44%

GE LOD	57,196	53,147	61,244	60%	56%	64%

GE 5	28,200	24,920	31,481	30%	26%	33%

GE 10	15,964	13,141	18,787	17%	14%	20%

GE 20	8,989	6,871	11,108	9%	7%	12%

GE 40	5,495	3,770	7,220	6%	4%	8%

GE 100 	2,426	1,470	3,382	3%	2%	4%

Missingf	123

	0%

Window Sills:

LT LOD	9,602	7,326	11,879	10%	8%	13%

GE LOD	82,134	78,850	85,418	86%	83%	88%

GE 125	20,338	17,590	23,085	21%	19%	24%

GE 250	13,439	11,516	15,362	14%	12%	16%

GE 500 	9,042	7,136	10,949	10%	8%	12%

No sill present in HUg	2,221	848	3,594	2%	1%	4%

Missingf	1,731

	2%

Window Troughs:

LT LOD	374	0	799	0%	0%	1%

GE LOD	72,638	67,107	78,169	76%	70%	82%

GE 800	21,210	16,489	25,931	22%	17%	27%

No trough present in HU	7,318	5,176	9,459	8%	5%	10%

Missingf	15,358

	16%

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	All percentages are calculated with total housing units (95,688) as
the denominator.

c	Floors include both carpeted and uncarpeted floors.

d	CI = 95% confidence interval for the estimated number or percent.

e	LT equals “less than.”  GE equals “greater than or equal to.”
LOD equals “limit of detection.”

f 	Missing means that the floor, sill, or trough was present, but that
no lead value is available (either the sample was not collected, e.g.,
due to inaccessibility or respondent refusal, or the laboratory did not
submit a value).

g 	No sill/trough present” means that there was no sill or trough in
the HU, e.g., windows were flush with the wall, or awning windows were
installed.

Table 5.3 presents the distribution of average dust lead loadings by
surface (floor, window sill, and window trough) for all U.S. homes in
the target population, for selected threshold values.  The average dust
loading for each surface was determined by simply adding floor, window
sill, or window trough dust loadings for each room sampled in each HU
and dividing by the number of rooms sampled (unweighted average).

The same trends are observed in Table 5.3 for average dust lead loadings
as for the distribution of maximum dust lead loadings in Table 5.2.
However, Table 5.3 shows that fewer homes have carpeted floor dust lead
hazards than uncarpeted floor dust hazards (i.e., carpeted floors have
lower dust lead loadings – as indicated by the results of the wipe
sampling employed in the survey).  In fact, the regression modeling
suggested that lead loadings on carpeted surfaces were approximately 25
percent lower than smooth and cleanable surfaces and 75 percent lower
than uncarpeted surfaces that were not smooth and cleanable (see Figure
C.7)

Table 5.3	Distribution of Average Dust Lead Loadings in Housing Units
by Surface

Average Dust Lead Loading

in HU (µg/sq ft)	Number of HUs (000)a	Percent of HUs (%)b

	Estimate	Lower

95% CIc	Upper

95% CI	Estimate	Lower

95% CI	Upper

95% CI

Floors (Uncarpeted):

LT LODd	51,252	47,180	55,323	54%	49%	58%

GE LOD	40,529	36,366	44,693	42%	38%	47%

GE 5	17,291	13,855	20,727	18%	14%	22%

GE 10	8,512	6,348	10,676	9%	7%	11%

GE 20	4,843	3,263	6,423	5%	3%	7%

GE 40	2,449	1,414	3,484	3%	2%	4%

GE 100 	966	239	1,694	1%	0%	2%

No Uncarpeted	3,907

	4%

Floors (Carpeted):

LT LODd	66,628	63,563	69,694	70%	67%	73%

GE LOD	21,356	18,700	24,012	22%	20%	25%

GE 5	5,806	4,073	7,540	6%	4%	8%

GE 10	2,374	1,488	3,261	3%	2%	3%

GE 20	1,368	674	2,061	1%	1%	2%

GE 40	298	0	634	0%	0%	1%

GE 100 	59	0	190	0%	0%	0%

No Carpeted	7,704

	8%

Window Sills:

LT LOD	12,800	10,201	15,399	13%	11%	16%

GE LOD	78,936	75,462	82,410	83%	80%	85%

GE 125	13,875	11,717	16,033	15%	12%	17%

GE 250	8,287	6,636	9,938	9%	7%	10%

GE 500 	4,900	3,611	6,190	5%	4%	7%

No sill present in HUe	2,221	848	3,594	2%	1%	4%

Missingf	1,731

	2%

Window Troughs:

LT LOD	663	52	1,274	1%	0%	1%

GE LOD	72,349	66,714	77,985	76%	70%	81%

GE 800	16,395	12,827	19,964	17%	13%	21%

No trough present in HU	7,318	5,176	9,459	8%	5%	10%

Missing	15,358

	16%

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	All percentages are calculated with total housing units (95,688) as
the denominator.

c	CI = 95% confidence interval for the estimated number or percent.

d	LT equals “less than.”  GT equals “greater than.” LOD equals
“limit of detection.”

e	“No sill/trough present” means that there was no sill or trough in
the HU, e.g., windows were flush with the wall, or awning windows were
installed.

f	Missing means that the floor, sill, or trough was present, but that no
lead value is available (either the sample was not collected, e.g., due
to inaccessibility or respondent refusal, or the laboratory did not
submit a value).

Table 5.4 presents the distribution of dust lead loadings by room type
and surface for selected threshold values.  The vast majority of floors
had undetectable levels of dust lead.  About 1 percent of rooms had dust
lead levels above the HUD Lead Safe Housing Rule standard for floors.
Five percent of rooms had dust lead levels above the HUD Lead Safe
Housing Rule standard for window sills.

Figure 5.5 presents a scatter plot of the window sill dust lead loadings
against the floor dust lead loadings.  Each point in Figure 5.5
represents the floor and window dust lead loadings from the same room in
the same housing unit.  The figure shows evidence of a moderate positive
correlation between the dust lead loadings on these two neighboring
surfaces.

Table 5.4	Distribution of Dust Lead Loading by Room and Surfaces

Dust Lead 	Kitchens	Living Rooms	Bedrooms	Other Rooms

Loading

(µg/sq ft)a	Number of Rooms (000)b	Percent of Rooms (%)c	Number of
Rooms (000)	Percent of Rooms (%)	Number of Rooms (000)	Percent of Rooms
(%)	Number of Rooms (000)	Percent of Rooms (%)

Floorsd

LT LODe	63,244	66%	98,433	78%	170,153	78%	231,924	73%

GE LOD	31,633	33%	26,732	21%	45,915	21%	84,438	27%

GE 5	14,062	15%	9,863	8%	19,340	9%	34,291	11%

GE 10	5,568	6%	4,287	3%	10,612	5%	18,933	6%

GE 20	2,571	3%	1,824	1%	4,175	2%	10,626	3%

GE 40	712	1%	880	1%	1,593	1%	7,477	2%

GE 100 	335	0%	170	0%	1,354	1%	785	0%

Missingf	488	1%	1,737	1%	1,002	1%	2,594	1%

Total Rooms	95,365	100%	126,902	100%	217,069	100%	318,956	100%

Window Sills

LT LOD	23,001	24%	29,378	23%	38,394	18%	44,841	14%

GE LOD	50,393	53%	72,154	57%	140,748	65%	141,008	44%

GE 125	7,037	7%	10,937	9%	20,393	9%	23,472	7%

GE 250	4,329	5%	6,731	5%	11,075	5%	17,156	5%

GE 500 	2,455	3%	4,386	4%	6,661	3%	10,096	3%

Missing	3,870	4%	5,462	4%	17,993	8%	16,321	5%

No Sills	18,102	19%	19,907	16%	19,934	9%	116,785	37%

Total Rooms	95,365	100%	126,902	100%	217,069	100%	318,956	100%

Window Troughs

LT LOD	3,293	4%	4,125	3%	5,211	2%	6,657	2%

GE LOD	49,962	52%	64,827	51%	122,752	57%	119,236	37%

GE 800	9,249	10%	12,795	10%	23,268	11%	21,487	7%

Missing	16,542	17%	27,537	22%	57,738	27%	58,044	18%

No Trough	25,568	27%	30,413	24%	31,368	15%	135,019	42%

Total Rooms	95,365	100%	126,902	100%	217,069	100%	318,956	100%

a	In this table, maximum loading is not applicable as only one dust
sample was collected from each surface in each room.

v	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

c	All percentages are calculated with total rooms of that type as the
denominator.

d	Floors include both carpeted and uncarpeted floors.

e	LT equals “less than.”  GE equals “greater than or equal to.”
LOD equals “limit of detection.”

f	Missing means that the floor, sill, or trough was present, but that no
lead value is available (either the sample was not collected, e.g., due
to inaccessibility or respondent refusal, or the laboratory did not
submit a value).

Figure 5.5	Association Between Dust Lead Loading on Floors and Window
Sills

Tables 5.5a through 5.5c present the distributions of floor, window
sill, and window trough dust lead loadings, respectively, by selected
thresholds and by year of construction.  It is evident that older homes
have considerably more dust lead than newer homes.  The percentage of
homes over the HUD Rule standard of 40 µg/ft2 for floor dust (Table
5.5a) increases from less than 1 percent for post-1977 homes to 16
percent for pre-1940 homes.  The percentage of homes over the sill dust
standard (Table 5.5b) steadily increases from 4 percent for post-1977
homes to 14 percent for 1940-1959 homes to 40 percent for pre-1940
homes.

Table 5.5a	Maximum Floor Dust Lead Loading by Year of Construction

Maximum Floor Dust	Year of Construction

Lead Loading(µg/sq ft)a	1978-1998	1960-1977	1940-1959	Before 1940

	Number (000)	Percent

(%)b	Number (000)	Percent

(%)	Number (000)	Percent

(%)	Number (000)	Percent

(%)

LT LODc	Number HUsd	17,487	59%	13,006	47%	5,667	28%	2,208	13%

	Lower 95% CIe	15,646	53%	10,272	38%	4,076	20%	782	4%

	Upper 95% CI	19,329	65%	15,740	56%	7,257	35%	3,635	21%

GE LOD	Number HUs	12,241	41%	14,868	53%	14,820	72%	15,268	87%

	Lower 95% CI	10,419	35%	12,454	44%	12,770	65%	13,008	79%

	Upper 95% CI	14,064	47%	17,281	62%	16,869	80%	17,527	96%

GE 5	Number HUs	3,233	11%	4,968	18%	8,753	43%	11,245	64%

	Lower 95% CI	2,285	8%	3,567	13%	7,060	35%	9,635	55%

	Upper 95% CI	4,181	14%	6,370	23%	10,446	50%	12,855	73%

GE 10	Number HUs	1,153	4%	2,488	9%	4,938	24%	7,386	42%

	Lower 95% CI	370	1%	1,607	6%	3,447	17%	5,802	33%

	Upper 95% CI	1,935	7%	3,369	12%	6,428	31%	8,970	52%

GE 20	Number HUs	97	0%	1,112	4%	2,784	14%	4,996	29%

	Lower 95% CI	0	0%	516	2%	1,283	6%	3,759	22%

	Upper 95% CI	267	1%	1,708	6%	4,286	21%	6,234	35%

GE 40	Number HUs	97	0%	588	2%	1,967	10%	2,843	16%

	Lower 95% CI	0	0%	216	1%	718	4%	1,989	11%

	Upper 95% CI	267	1%	961	4%	3,215	16%	3,698	21%

GE 100	Number HUs	97	0%	280	1%	935	5%	1,114	6%

	Lower 95% CI	0	0%	0	0%	121	1%	587	3%

	Upper 95% CI	267	1%	640	2%	1,750	9%	1,642	9%

Missing	Number HUs	0	0%	0	0%	77	0%	0	0%

a	Floors include both carpeted and uncarpeted floors.

b	All percentages are calculated with total housing units (95,688) as
the denominator.

c	LT equals “less than.”  GE equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

Table 5.5b	Maximum Window Sill Dust Lead Loading by Year of
Construction

Maximum Floor Dust	Year of Construction

Lead Loading(µg/sq ft)a	1978-1998	1960-1977	1940-1959	Before 1940

	Number (000)	Percent

(%)b	Number (000)	Percent

(%)	Number (000)	Percent

(%)	Number (000)	Percent

(%)

LT LODc	Number HUsd	6,196	21%	1,924	7%	1,074	5%	408	2%

	Lower 95% CIe	4,270	14%	826	3%	277	1%	0	0%

	Upper 95% CI	8,122	27%	3,021	11%	1,871	9%	835	5%

GE LOD	Number HUs	21,823	73%	24,729	89%	18,779	91%	16,803	96%

	Lower 95% CI	19,833	68%	22,996	84%	16,956	87%	15,103	93%

	Upper 95% CI	23,814	79%	26,462	94%	20,602	96%	18,503	99%

GE 125	Number HUs	1,806	6%	4,097	15%	5,407	26%	9,028	52%

	Lower 95% CI	578	2%	2,444	9%	3,954	19%	7,196	42%

	Upper 95% CI	3,033	10%	5,749	21%	6,860	33%	10,861	61%

GE 250	Number HUs	1,029	4%	1,755	6%	3,712	18%	6,943	40%

	Lower 95% CI	139	1%	1,086	4%	2,556	12%	5,476	31%

	Upper 95% CI	1,919	7%	2,424	9%	4,867	24%	8,410	48%

GE 500	Number HUs	447	2%	747	3%	2,869	14%	4,980	29%

	Lower 95% CI	0	0%	274	1%	1,779	9%	3,712	21%

	Upper 95% CI	1,024	3%	1,219	4%	3,959	19%	6,247	36%

Missing	Number HUs	299	1%	851	3%	361	2%	220	1%

No sills	Number HUs	1,456	5%	371	1%	349	2%	45	0%

	Lower 95% CI	456	2%	0	0%	0	0%	0	0%

	Upper 95% CI	2,456	8%	762	3%	730	4%	143	1%

a	Missing means that the sill was present, but that no lead value is
available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).  “No sill present” means that there was no sill in the HU,
e.g., windows were flush with the wall, or awning windows were
installed.

b	All percentages are calculated with total housing units (95,688) as
the denominator.

c	LT equals “less than.”  GT equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

Table 5.5c	Maximum Window Trough Dust Lead Loading by Year of
Construction

Maximum Window Trough

Dust Lead Loading (µg/sq ft)a	Year of Construction

	1978-1998	1960-1977	1940-1959	Before 1940

	Number (000)	Percent

(%)b	Number (000)	Percent

(%)	Number (000)	Percent

(%)	Number (000)	Percent

(%)

LT LODc	Number HUsd	280	1%	94	0%	0	0%	0	0%

	Lower 95% CIe	0	0%	0	0%	0	0%	0	0%

	Upper 95% CI	681	2%	235	1%	0	0%	0	0%

GE LOD	Number HUs	20,969	70%	20,319	73%	16,406	80%	14,943	86%

	Lower 95% CI	17,718	60%	17,730	64%	14,638	73%	13,192	80%

	Upper 95% CI	24,221	81%	22,909	82%	18,174	86%	16,694	91%

GE 800	Number HUs	2,252	8%	3,788	14%	6,286	31%	8,883	51%

	Lower 95% CI	1,032	4%	2,504	9%	4,500	21%	7,084	41%

	Upper 95% CI	3,473	12%	5,072	18%	8,073	40%	10,683	61%

Missing	Number HUs	4,184	14%	5,885	21%	2,966	14%	2,322	13%

No troughs	Number HUs	4,341	15%	1,576	6%	1,191	6%	210	1%

	Lower 95% CI	2,380	8%	732	3%	368	2%	0	0%

	Upper 95% CI	6,301	21%	2,419	9%	2,014	10%	451	3%

a	Missing means that the trough was present, but that no lead value is
available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).  “No trough present” means that there was no trough in the
HU, e.g., windows were flush with the wall, or awning windows were
installed.

b	All percentages are calculated with total housing units of that age as
the denominator.

c	LT equals “less than.”  GT equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live

e	CI = 95% confidence interval for the estimated number or percent.

Tables 5.6a through 5.6c present floor, window sill, and window trough
dust loading distributions by household income level.  There are some
significant differences shown in the table.  A greater percent of homes
in the higher income level have lower lead dust loadings.  For example,
47 percent of higher income homes have lead dust loadings on floors
below the limit of detection, while only 29 percent of homes in the
lower income level have loadings below the limit of detection.  Only 1
percent of homes in the higher household income level exceed 100 (g/ft2
floor dust lead loading, while 5 percent of lower income level homes
exceed this loading.  Similar trends are observed for window sill and
trough dust loadings.

Although the data have not been presented, there were no apparent
differences between urbanization categories and dust lead loadings.

Table 5.6a	Maximum Floor Dust Lead Loadings by Household Income

g/sq ft)a	Household Income

	Less than $30,000/year	Equal to or above $30,000/year

	Number (000)	Percent (%)b	Number (000)	Percent (%)

LT LODc	Number HUsd	9,747	29%	26,508	47%

	Lower 95% CIe	6,944	23%	22,360	42%

	Upper 95% CI	12,550	35%	30,657	53%

GE LOD	Number HUs	24,038	71%	29,525	53%

	Lower 95% CI	19,932	65%	26,065	47%

	Upper 95% CI	28,143	77%	32,985	58%

GE 5	Number HUs	13,364	40%	13,215	24%

	Lower 95% CI	10,562	32%	10,859	20%

	Upper 95% CI	16,166	47%	15,571	27%

GE 10	Number HUs	8,276	25%	6,792	12%

	Lower 95% CI	6,219	19%	5,052	9%

	Upper 95% CI	10,332	30%	8,532	15%

GE 20	Number HUs	4,282	13%	4,135	7%

	Lower 95% CI	3,117	9%	2,782	5%

	Upper 95% CI	5,447	17%	5,488	10%

GE 40	Number HUs	2,819	8%	2,170	4%

	Lower 95% CI	1,710	5%	924	2%

	Upper 95% CI	3,927	12%	3,415	6%

GE 100	Number HUs	1,637	5%	435	1%

	Lower 95% CI	728	2%	57	0%

	Upper 95% CI	2,546	8%	813	1%

Missing	Number HUs	46	0%	77	0%

a	Missing means that the sill or trough was present, but that no lead
value is available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).

b	All percentages are calculated with total housing units in that income
class as the denominator.

c	LT equals “less than.”  GT equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

g/sq ft)a	Household Income

	Less than $30,000/year	Equal to or Above $30,000/year

	Number (000)	Percentb	Number (000)	Percent

LT LODc	Number HUsd	1,448	4%	7,111	13%

	Lower 95% CIe	376	1%	5,291	9%

	Upper 95% CI	2,520	7%	8,931	16%

GE LOD	Number HUs	29,948	89%	47,597	85%

	Lower 95% CI	24,656	84%	42,665	81%

	Upper 95% CI	35,241	93%	52,528	89%

GE 125	Number HUs	10,322	31%	8,865	16%

	Lower 95% CI	7,909	26%	6,896	13%

	Upper 95% CI	12,735	36%	10,835	19%

GE 250	Number HUs	7,671	23%	4,772	9%

	Lower 95% CI	5,776	18%	3,611	7%

	Upper 95% CI	9,565	28%	5,933	11%

GE 500	Number HUs	4,395	13%	3,893	7%

	Lower 95% CI	2,943	9%	2,773	5%

	Upper 95% CI	5,846	17%	5,014	9%

Missing	Number HUs	1,137	3%	594	1%

No sills	Number HUs	1,297	4%	809	1%

	Lower 95% CI	250	1%	151	0%

	Upper 95% CI	2,345	7%	1,466	3%

a	Missing means that the sill or trough was present, but that no lead
value is available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).  “No sill/trough present” means that there was no sill or
trough in the HU, e.g., windows were flush with the wall, or awning
windows were installed.

b	All percentages are calculated with total housing units in that income
class as the denominator.

c	LT equals “less than.”  GT equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

Table 5.6c	Maximum Window Trough Lead Dust Loadings by Household Income

g/sq ft)a	Household Income

	Less than $30,000/year	Equal to or Above $30,000/year

	Number (000)	Percentb	Number (000)	Percent

LT LODc	Number HUsd	59	0%	315	1%

	Lower 95% CIe	0	0%	0	0%

	Upper 95% CI	180 	1%	723	1%

LT 800	Number HUs	25,985	77%	42,253	75%

	Lower 95% CI	21,486	70%	37,300	69%

	Upper 95% CI	30,485	84%	47,205	81%

GE 800	Number HUs	9,449	28%	10,623	19%

	Lower 95% CI	6,742	20%	8,067	15%

	Upper 95% CI	12,156	36%	13,179	23%

Missing	Number HUs	5,624	17%	8,788	16%

No troughs	Number of HUs	2,162	6%	4,755	9%

	Lower 95% CI	869	3%	3,009	5%

	Upper 95% CI	3,456	10%	6,501	12%

a	Missing means that the sill or trough was present, but that no lead
value is available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).  “No sill/trough present” means that there was no sill or
trough in the HU, e.g., windows were flush with the wall, or awning
windows were installed.

b	All percentages are calculated with total housing units in that income
class as the denominator.

c	LT equals “less than.  “GE equals “greater than or equal to.”
LOD equals “limit of detection.”

d	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

Figure 5.6 shows the distribution of the dust lead loadings by room
type: kitchen, common living area, bedroom, and other room.    For these
four room types, both floor dust and window dust have been combined.
Dust loadings for the main entrance are also shown in the figure, but
these are only floor loadings since no data were collected from main
entrance windows.  Figure 5.7 shows the distribution of the dust lead
measurements by surface and carpet.  In both figures, the distributions
are extremely right-skewed.  Except for troughs, none of the boxes
extend above 40 µg/ft2, which means that the 75th percentile is less
than 40 µg/ft2.  However, there are dust lead loadings well above
10,000 µg/ft2.  On troughs, they extend above 100,000 µg/ft2.

Table 5.7 presents selected parameters of the distributions of dust lead
loadings by surface types, corresponding to the boxplots in Figure 5.7.
Table 5.7 also presents geometric means and standard deviations.  The
distributions in Table 5.7 are all right-skewed, so that they are not
normally distributed.  A better model would be the lognormal
distribution.  Appendix C includes a discussion of distributional models
for these data.

Figure 5.6	Box Plots for Dust Lead Loadings by Room

a	The first four plots include floor and window loadings.  Main entrance
only includes floors since no data were collected from main entrance
windows.

b 	The box in the box plot represents the middle 50 percent of the data;
the bottom of the box gives the 25th percentile; the top of the box
gives the 75th percentile, and the horizontal line inside the box gives
the median or 50th percentile.  The vertical lines extending from the
top and bottom of the box reach to the largest and smallest
observations, respectively, except for outliers.

Figure 5.7	Box Plots for Dust Lead Loadings by Surface

a 	The box in the box plot represents the middle 50 percent of the data;
the bottom of the box gives the 25th percentile; the top of the box
gives the 75th percentile, and the horizontal line inside the box gives
the median or 50th percentile.  The vertical lines extending from the
top and bottom of the box reach to the largest and smallest
observations, respectively, except for outliers.

Table 5.7	Estimated Empirical Distribution Parameters of Dust Lead
Loadings by Surface Types

	Floors	Window Sills	Window Troughs

	(g/ft2	(g/ft2	(g/ft2

Arithmetic Mean	13.6	194.9	1,990.9

Arithmetic Standard Deviation	483.5	1682.7	12,086.5

Geometric Mean 	1.1	9.4	96.4

Geometric Standard Deviationa	3.8	9.3	14.4

25th Percentile	.375	2.0	18.0

Median	0.9	8.3	89.1

75th  Percentile	2.0	37.13	462.0

90th Percentile	6.0	172.8	2,824.2

95th Percentile	13.2	524.9	6,974.6

Number of Samples	3,894	2,302	1,607

a	The geometric standard deviation is computed as exp(s), where s is the
arithmetic standard deviation of the natural logarithms of the loadings
(see, e.g., Gilbert, R. O. (1987) Statistical Methods for Environmental
Pollution Monitoring, Van Nostrand Reinhold Company New York).

b	For this table, values below 0.375 were set equal to 0.375, which is
¼ of the limit of detection.

5.3	Association between Interior Dust Lead Hazards and Interior LBP
Condition

Figure 5.8 presents the prevalence of interior dust lead hazards in
relation to the condition of the interior LBP.  Table 5.8 presents
further details on these estimates.  Dust lead hazards are more likely
to exist in homes with deteriorated LBP.  An estimated 61 percent (+20%)
of homes with significantly deteriorated LBP have lead dust hazards,
while only 33 percent (+7%) of homes with LBP in good condition have
lead dust hazards.  Only 6 percent (+2%) of homes with no interior LBP
have lead dust hazards.  Although it appears from the data that the
presence of LBP, especially significantly deteriorated LBP, contributes
to higher dust lead hazard, there are additional sources of lead in the
environment to account for dust lead in homes with no lead-based paint.

Table 5.8 also allows one to compare the relative risks (95 percent
confidence intervals on that risk are not shown in the table) of
interior lead dust hazards associated with different paint conditions.
The presence of significantly deteriorated LBP makes a house 1.8 (+0.5)
times as likely to have an interior lead dust hazard compared to a house
where the LBP is in good condition, and 10.0 (+1.9) times as likely as a
house without LBP.  Even a house with LBP in good condition is 5.4
(+0.8) times as likely to have interior lead dust hazards as one without
any LBP.

Paint

Table 5.8	Association Between Dust Lead Hazards and Presence and
Condition of Interior Lead-Based Paint

Interior Dust Lead Hazards	No LBP on Interior or Exterior	No Interior
LBP	Interior LBP in Good Condition	Significantly Deteriorated Interior
LBP

	Number (000)	Percent

(%)	Number (000)	Percent

(%)	Number (000)	Percent

(%)	Number (000)	Percent

(%)

None Present	Estimatea	55,105	95%	62,752	94%	15,244	67%	2,389	39%

	Lower 95% CIb	51,893	90%	60,141	90%	12,633	56%	1,565	26%

	Upper 95% CI	58,318	100%	65,363	98%	17,855	78%	3,213	53%

Some Present	Estimate	2,686	5%	4,068	6%	7,508	33%	3,727	61%

	Lower 95% CI	1,372	2%	2,584	4%	6,024	26%	2,505	41%

	Upper 95% CI	4,001	7%	5,552	8%	8,992	40%	4,949	81%

Total HUs

57,791	100%	66,820	100%	22,752	100%	6,116	100%

a	Estimate is either the number of permanently occupied,
noninstitutional housing units (000) in which children are permitted to
live, or the percentage of total housing units.

b	CI = 95% confidence interval for the estimated number or percent.

Tables 5.9 and 5.10 present data on the association between floor and
sill dust lead loadings and the presence of interior lead-based paint.
Both tables show a positive relationship between the presence of
interior lead-based paint and dust lead levels.  Housing units with some
interior LBP are twice as likely to have floor dust, and three times as
likely to have window sill dust, above hazardous levels compared to
housing units without LBP.

Table 5.9	Association Between Floor Dust Lead Loadings and Presence of
Interior Lead-Based Paint

Maximum Floor Dust Lead

Loading (g/sq ft)a	Interior Lead Based Paint

	None Present	Some Present

	Number (000)	Percent (%)b	Number (000)	Percent (%)

LT LODc	Number HUsd	32,873	34%	5,496	6%

	Lower 95% CIe	29,475	31%	3,529	4%

	Upper 95% CI	36,270	38%	7,463	8%

GE LOD	Number HUs	33,824	35%	23,372	24%

	Lower 95% CI	30,086	31%	19,997	21%

	Upper 95% CI	37,561	39%	26,748	28%

GE 5	Number HUs	12,242	13%	15,958	17%

	Lower 95% CI	9,835	10%	13,372	14%

	Upper 95% CI	14,650	15%	18,544	19%

GE 10	Number HUs	6,003	6%	9,961	10%

	Lower 95% CI	4,238	4%	7,615	8%

	Upper 95% CI	7,768	8%	12,307	13%

GE 20	Number HUs	2,493	3%	6,496	7%

	Lower 95% CI	1,606	2%	4,661	5%

	Upper 95% CI	3,381	4%	8,331	9%

GE 40	Number HUs	1,666	2%	3,830	4%

	Lower 95% CI	993	1%	2,378	3%

	Upper 95% CI	2,338	3%	5,281	6%

GE 100	Number HUs	1,122	1%	1,304	1%

	Lower 95% CI	419	0%	654	1%

	Upper 95% CI	1,825	2%	1,954	2%

Missing	Number HUs	123

	a	Missing means that the sill or trough was present, but that no lead
value is available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).

b	All percentages are calculated with total housing units as the
denominator.

c	LT equals "less than." GE equals "greater than or equal to." LOD
equals "limit of detection."

d	"Housing units" include permanently occupied, noninstitutional housing
units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

Table 5.10	Association Between Window Sill Dust Lead Loadings and
Presence of Interior Lead-Based Paint

Maximum Window Sill  Dust Lead

Loading (g/sq ft)a	Interior Lead Based Paint

	None Present	Some Present

	Number (000)	Percent (%)b	Number (000)	Percent (%)

LT LODc	Number HUsd	8,728	9%	874	1%

	Lower 95% CIe	6,544	7%	187	0%

	Upper 95% CI	10,912	12%	1,562	2%

GE LOD	Number HUs	54,454	57%	27,680	29%

	Lower 95% CI	51,195	54%	24,515	26%

	Upper 95% CI	57,713	60%	30,845	32%

GE 125	Number HUs	6,553	7%	13,785	14%

	Lower 95% CI	5,043	5%	11,177	12%

	Upper 95% CI	8,063	8%	16,393	17%

GE 250	Number HUs	3,434	4%	10,005	11%

	Lower 95% CI	2,193	2%	8,096	9%

	Upper 95% CI	4,675	5%	11,914	13%

GE 500	Number HUs	1,498	2%	7,544	8%

	Lower 95% CI	651	1%	5,770	6%

	Upper 95% CI	2,346	3%	9,318	10%

No sill present in HUa	Number HUs	2,043	0%	178	0%

Missing	Number HUs	1,595

136

	a	Missing means that the sill was present, but that no lead value is
available (either the sample was not collected, e.g., due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).

b	All percentages are calculated with total housing units as the
denominator.

c	LT equals "less than." GE equals "greater than or equal to." LOD
equals "limit of detection."

d	"Housing units" include permanently occupied, noninstitutional housing
units in which children are permitted to live.

e	CI = 95% confidence interval for the estimated number or percent.

6.  RESIDENTIAL SOIL LEAD

Chapter 6 presents estimates of the prevalence of soil lead by lead
concentration, and the association between soil lead concentration and
exterior lead-based paint condition.  Relevant estimates are compared
with the findings of the 1990 LBP Survey.  The prevalence of soil lead
hazards in housing is presented in Chapter 3.  Since soil lead hazards
include lead in soil in children’s play areas, most estimates in this
Chapter are based on the subsample of 375 homes with data on the
presence or absence of children’s play areas in the yards and on the
extent of soil lead hazards in children’s play areas.  A few tables in
this chapter are independent of the presence or absence of
lead-contaminated soil in children’s play areas; such tables are
therefore based on the full sample and have a footnote indicating that
the basis is the full sample.

6.1	Prevalence of Residential Soil Lead Over All Sampled Locations

A composite soil sample was collected at each of five sites on the
property of each dwelling unit: 1) near the most commonly used entrance,
2) the dripline and 3) the mid-yard line of the wall with the main
entrance, and 4) the dripline and 5) mid-yard line of a second,
randomly-selected wall.  The main entrance sample was a composite sample
of two cores from the main entrance area.  The dripline and mid-yard
samples on each wall were composite samples from three locations along
the length of the sample site.  In addition, soil samples were collected
from children’s play areas for a subsample of homes.  At each of these
homes, up to four samples were collected from children’s play
equipment, when present; otherwise, one sample was collected from an
area of the yard identified as being where children play.  The tables in
this section and in Section 6.2 are based on the lead concentration data
from all of these soil samples, referenced as “all sampled
locations.”  Section 6.3 then presents data on soil lead
concentrations in children’s play areas, while Section 6.4 presents
corresponding data for the “rest of the yard,” i.e., areas not
identified as children’s play areas.

Figure 6.1 and Table 6.1 present the distribution of maximum bare soil
lead concentrations.  Figure 6.1 presents a histogram of the
distribution, while Table 6.1 presents the number and percentage of HUs
by selected soil lead concentration thresholds:  0, 20, 50, 200, 400,
1,200, 1,600, 2,000, and 5,000 ppm.  Figure 6.1 and Table 6.1 include
bare soil from all sampled locations, both play areas and all other
locations.  An estimated 58 percent ((8%) of homes have soil lead levels
above the limit of detection.  An estimated 10 percent ((4%) of homes
have soil lead levels above 400 ppm, and 7% ((4%) have soil lead levels
above 1,200 ppm.  Only 3 percent of homes were found to have soil lead
above 2,000 ppm. The maximum soil values for each HU have been used in
Table 6.1.  The effect of using the average soil lead for each HU would
drive the distribution towards the lower thresholds, i.e. more homes
have lower average soil lead concentrations.

Care is to be exercised in comparing the tables in this Chapter with
Table 3.3, which tabulate the prevalence of soil lead hazards.  The
tables in this chapter present the distribution of residential soil lead
concentrations at selected locations, while soil lead hazards are
defined in terms of soil lead concentrations in two types of locations.
Specifically, a housing unit is defined to have a soil lead hazard if
soil lead concentrations exceed 400 ppm in play areas or exceed 1,200
ppm in the rest of the yard.  Thus, the tables in this section do not
directly compare with Table 3.3.

Figure 6.1	Distribution of Maximum Bare Soil Lead Concentrations

Table 6.1	Distribution of Maximum Bare Soil Sample Lead Concentrations
(All Sampled Locations)

Bare Soil Lead	Number of HUs (000)a	Percent of HUs (%)b

Estimate	Lower

95% CIc	Upper

95% CI

Estimate	Lower

95% CI	Upper

95% CI

GEd0 ppm	77,888	72,054	83,722	81%	75%	88%

GE 20 ppm	55,114	47,348	62,881	58%	50%	66%

GE 50 ppm	40,023	31,365	48,680	42%	33%	51%

GE 200 ppm	15,299	11,626	18,971	16%	12%	20%

GE 400 ppm	9,996	6,398	13,594	10%	7%	14%

GE 1,200 ppm	6,271	2,733	9,809	7%	3%	10%

GE 1,600 ppm	3,900	1,670	6,131	4%	2%	6%

GE 2,000 ppm	3,124	827	5,420	3%	1%	6%

GE 5,000 ppm	1,580	0	3,309	2%	0%	4%

No Bare Soil	15,413	9,789	21,037	16%	10%	22%

No Soil	2,242	330	4,154	2%	0%	4%

Missinge	145	0	527	0%	0%	1%

a	“Housing units” include permanently occupied, noninstitutional
housing units in which children are permitted to live.

b	All percentages are calculated with total housing units (95,688) as
the denominator.

c	CI = 95% confidence interval for the estimated number or percent.

d	GE equals “greater than or equal to.”

e	“Missing” means that soil was present, but that no lead value is
available (either the sample was not collected, e.g. due to
inaccessibility or respondent refusal, or the laboratory did not submit
a value).  “No soil” means that there was no soil on the property to
sample.

Table 6.2 presents the number and percentage of housing units by
construction year for selected soil lead concentration thresholds for
bare soil only, again for all sampling locations. As seen above for all