EPA 747-S-00-001
January 2000
LEAD EXPOSURE ASSOCIATED WITH
RENOVATION AND REMODELING ACTIVITIES
FINAL SUMMARY REPORT
Prepared by
BATTELLE
505 King Avenue
Columbus, Ohio 43201-2693
for
Technical Branch
National Program Chemicals Division
Office of Pollution Prevention and Toxics
U.S. ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
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This is a report of research performed for the United States Government
by Battelle. Because of the uncertainties inherent in experimental or research
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beyond any express obligations embodied in the governing written agreement
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TABLE OF CONTENTS
Page
1.0 INTRODUCTION 1
2.0 PHASE I: ENVIRONMENTAL FIELD SAMPLING STUDY 2
2.1 PHASE I: DESIGN 2
2.2 PHASE I: RESULTS 3
3.0 PHASE II: WORKER CHARACTERIZATION AND BLOOD-LEAD STUDY 4
3.1 PHASE II: DESIGN 4
3.2 PHASE II: RESULTS 4
4.0 PHASE III: WISCONSIN CHILDHOOD BLOOD-LEAD STUDY 5
4.1 PHASE III: DESIGN 5
4.2 PHASE III: RESULTS 5
5.0 PHASE IV: WORKER CHARACTERIZATION AND BLOOD-LEAD STUDY OF WORKERS
AND HOMEOWNERS PERFORMING R&R IN HISTORIC HOMES 6
5.1 PHASE IV: DESIGN 6
5.2 PHASE IV: RESULTS 7
6.0 CONCLUSIONS 8
7.0 REFERENCES 8
List of Tables
Table 1. Summary Measures of Worker Exposure to Airborne Lead (Phase I) 10
Table 2. Summary Measures of Potential Occupant Lead Exposures that Can Result
from Conducting Target and Generic R&R Activities (Phase I) 11
Table 3. Information for an Assessment of Worker Exposures Associated with Different
R&R Worker Groups (Phases II and IV) 13
Table 4. Predicted Changes in General Worker Blood-Lead Concentrations Associated
with 10 Days of Work in Pre-1950 Buildings (Phase II) 14
Table 5. Unconditional Odds Ratios from Logistic Regression with Single R&R Variables
(Phase III) 15
Table 6. Predicted Changes in High-Risk Worker Blood-Lead Concentrations (|Jg/dL)
Associated with 10 Days of Work in Pre-1940 Homes (Phase IV) 17
Table 7. Predicted Changes in Homeowner Blood-Lead Concentrations (|Jg/dL) Associated
With Changes in the Number of Hours Spent Performing a Target Activity in
Their Pre-1940 Home (Phase IV) 17
List of Figures
Figure 1. Hours of Activity That Would Result in an Estimated Geometric Mean 8-Hour
TWA of 50 |Jg/m3 (Phase I) 11
Figure 2. Estimated Distribution of Dust Lead in a 6' x 1' Region Extending from the
Activity Area for Various Activities (Phase I) 12
in
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TABLE OF CONTENTS (Continued)
Figure 3. Histogram of Blood-Lead Concentration (Semi-Logarithmic Scale) for Workers
in the WCBS (Phase II) 12
Figure 4. Histogram of Homeowner Blood-Lead Concentration (Semi-Logarithmic Scale)
(Phase IV) 16
Figure 5. Histogram of Blood-Lead Concentration (Semi-Logarithmic Scale) for Workers
Specializing in R&R of Historic/Old Homes (Phase IV) 16
IV
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1.0 INTRODUCTION
The phased elimination of lead additives from motor fuels during the 1970s and 1980s
and restrictions on the use of lead in paint and solder have resulted in large declines in
blood-lead levels over the past decade. Childhood lead poisoning, however, continues to be a
serious environmental health problem in the United States. Chief among the remaining sources
of public lead exposures is lead-based paint on the interior surfaces of older buildings, including
dwellings, public buildings, and commercial structures.
In 1978, maximum allowable content limits were placed on the use of lead in paint used
for toys, residences, and most furniture by the Consumer Product Safety Commission (CPSC).
Nevertheless, substantial quantities of lead-based paint, some of it covered with more than one
layer of newer paint or other wall covering, remain in the older building stock, particularly
dwellings and public buildings constructed before 1950. Lead-based paint that is chipping,
peeling, or otherwise deteriorating is widely recognized as a source of lead exposure for toddlers
and young children in older neighborhoods. Increasingly, environmental and public health
researchers have become concerned that disturbing intact lead-based paint or otherwise
mobilizing lead dust behind woodwork, window frames, in walls, etc., during renovation and
remodeling (R&R) of older buildings can expose construction workers and building occupants to
high lead levels.
To address this concern, Congress directed the U.S. Environmental Protection Agency
(EPA) as part of the 1992 Residential Lead-Based Paint Hazard Reduction Act (Title X of HR
5334) to conduct a study of lead exposure associated with R&R. Specifically, Title IV of the
Toxic Substances Control Act, Section 402 (c), paragraph (2), states:
"The Administrator shall conduct a study of the extent to which persons engaged in
various types of renovation and remodeling activities in target housing1, public buildings
constructed before 1978, and commercial buildings are exposed to lead in the conduct of
such activities or disturb lead and create a lead-based paint hazard on a regular or
occasional basis."
Accordingly, EPA undertook research to examine lead exposures for different categories of:
Persons— R&R workers, occupants of buildings where lead-based paint is
present and R&R activities are carried out, particularly children and other
potentially exposed persons (i.e., persons who renovate or remodel their own old
or historic houses ["do-it-yourselfers"]).
• Activities— R&R activities deemed to entail potential lead exposure (e.g., paint
removal, surface preparation, interior demolition). Eleven such target activities
were identified through consultation with other government agencies, lead
poisoning prevention experts, industry representatives, labor unions, and other
concerned groups.
1 "Target housing" is defined by the Act as housing constructed before 1978.
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The study had two objectives:
1. Determine the extent to which persons engaged in various types of R&R activities
are exposed to lead.
2. Determine the extent to which persons engaged in various types of R&R activities
disturb lead and create a lead-based paint hazard, on a regular or occasional basis,
to building occupants or other exposed individuals.
An optimal study design would involve measuring worker and occupant blood-lead
concentrations and environmental-lead levels before, during, and after R&R activities.
Unfortunately, this design was not feasible due to substantial ethical and legal reasons.
Therefore, the study was conducted in a series of four independent data collection efforts
(phases) undertaken from 1993 to 1998.
The first two data collection efforts were conducted to characterize the environmental
lead disturbance resulting from R&R activities (Phase I) and to focus on the effect of R&R
activity on worker blood-lead concentrations through a retrospective study (Phase II). After the
completion of these data collection efforts, additional studies (Phase III and Phase IV) were
completed to address two remaining, significant data gaps. Phase III was designed to move
beyond Phase I to assess the relationship between the incidence of R&R activity and elevated
blood-lead concentrations in children. Phase IV was designed to assess whether there exists a
subset of R&R workers or homeowners, performing R&R work in high-risk homes, that have an
increased risk of elevated blood-lead concentrations.
Although some design aspects were employed in multiple phases, each of these four
phases was a distinct data collection effort and all phases were conducted in different locations,
at different times, and with different sample populations. The next four chapters present the
specific study design and results for each phase of the R&R Study.
2.0 PHASE I: ENVIRONMENTAL FIELD SAMPLING STUDY
2.1 PHASE I: DESIGN
The first data collection effort of the R&R Study was the Environmental Field Sampling
Study (EFSS), which assessed the relative distribution of exposure to lead created by selected
R&R activities. The EFSS focused on monitoring six specific R&R activities rather than
specific worker groups. The activities included: removal of large structures (demolition),
window replacement, carpet removal, heating, ventilating, and air conditioning (HVAC) repair
or replacement, surface preparation, and repairs with small surface disruption. Exposures from
exterior siding, wallpaper removal, and exterior soil disruption were not evaluated because they
were considered of secondary importance by the study design team and the individuals consulted
in the information-gathering phase.
For each monitored R&R activity, buildings containing lead-based paint suitable for
typical application of the activity were selected. Environmental measurements of lead were
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taken before, during, and after conducting the target activity. The measurements taken in the
EFSS included:
Personal Air Samples. Measures of airborne lead concentrations at a fixed flow
rate within each worker's personal breathing zone were collected by taking air
samples through a cassette filter mounted to the worker's lapel. These samples
were used to provide a measure of the potential inhalation exposure for workers.
Room (Ambient) Air Samples. Ambient air samples were collected for selected
activities in areas adjacent to the activity. Adjacent areas were used to address
the levels at which occupants might be exposed to airborne lead in other parts of
the building while the activity was being conducted.
Settled Dust Samples. Settled dust samples were taken either from stainless
steel dustfall collectors or from selected areas such as floors, window sills,
window wells, and carpets. Samples were collected at varying distances from the
surfaces disturbed by the activity. Lead loadings from settled dust samples were
measured as indicators of the amount of lead disturbed by the activity and
available as a potential exposure to occupants.
The EFSS was supplemented by an extensive search for other sources of data that could
be used either to fulfill data requirements for a specific activity or to confirm results obtained in
the Environmental Study.
2.2 PHASE I: RESULTS
Airborne lead levels in a worker's breathing zone, representing an average exposure over
the duration that R&R activity was performed, were often very high during many R&R activities
(see Table 1). These levels averaged greater than 100 |_ig/m3 (micrograms of lead per
cubic meter of air) for paint removal, interior demolition, and sawing activities, and greater than
49 |-ig/m3 for interior surface preparation and disturbance of the central heating system ductwork.
Average levels were considerably lower (< 20 |_ig/m3) for drilling, carpet removal, window
replacement, and exterior surface preparation. These personal exposure measurements reflect
only the period of conducting the specific R&R activity and do not represent average exposures
over an 8-hour day for a worker. In addition, results were based on selected case studies and
small sample sizes. Nevertheless, a number of personal exposure measurements in the R&R
Study were high enough to imply that conducting the activity for even a short period of time,
with no exposure during the rest of the work day, would result in an 8-hour time-weighted-
average (TWA) above the OSHA personal exposure limit (PEL). For each activity, Figure 1
presents the minimum duration of activity that, on average, would be necessary to achieve an
8-hour TWA of 50 |-ig/m3, based on the limited personal exposure data collected in this study.
Occupant exposure to lead in buildings was assessed by analyzing samples of dust
deposited as a result of R&R activities. With the exception of carpet removal and drilling into
plaster, all monitored activities deposited considerable amounts of lead, well over the current
EPA guidance of 100 |_ig/ft2 for floors (see Table 2, Figure 2). Paint removal, demolition,
sawing, and disturbing central heating system ductwork were more likely to cause airborne lead
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to scatter and settle over a widespread area, while window replacement and drilling confined the
disturbed lead to a smaller area. Simple broom and shop-vacuum cleanup resulted in substantial
reduction in the total amount of lead available to occupants. However, as the distance from the
activity increased, the cleanup left more lead in the remaining dust. In addition, the average
amount of lead remaining after cleanup often stayed above EPA's current guidance on bare floor
dust levels (100
3.0 PHASE II: WORKER CHARACTERIZATION AND BLOOD-LEAD STUDY
3.1 PHASE II: DESIGN
The second data collection effort of the R&R Study was the Worker Characterization and
Blood-Lead Study (WCBS). The WCBS involved collecting questionnaire information and
blood-lead measurements from 585 R&R workers in two cities to (1) characterize blood-lead
concentrations in specific worker groups, (2) determine if specific worker groups or specific
R&R activities are associated with increases in blood-lead concentrations, and (3) collect
information to be used to develop worker profiles. The WCBS was intended to obtain
information independent from the Environmental Field Sampling Study that would provide a
direct measure of health effects on worker exposure to lead and to validate the results of the
Environmental Field Sampling Study. Target R&R activities examined in the WCBS included
removal of large structures (demolition), window replacement, carpet removal, HVAC repair or
replacement, and paint removal/surface preparation. Post-activity cleanup was also assessed.
3.2 PHASE II: RESULTS
The questionnaire employed in Phase II captured data on how often each worker
conducted specific target activities in any home, including pre-1950 homes, during the past
30 days. The questionnaire results indicated that the sampled workers spent an average of
17 days during the previous month on general renovation and remodeling. The workers spent an
average of 11 of these 17 days in pre-1950 homes. The questionnaire results also indicated that:
1. The R&R workers performed a wide variety of R&R activities, and spent
considerable time removing large structures, removing paint, and preparing
surfaces, activities with potential for creating high dust-lead exposure.
2. Ninety percent of the workers did not use a respirator.
3. Eighty-eight percent of the workers who performed cleanup activities did not use
cleanup methods recommended for use in a lead-contaminated environment, and
99 percent used dry sweeping.
4. Of workers who performed paint removal, 97 percent used dry methods.
5. Sixty-seven percent of the workers had not received any materials on lead
hazards, and 87 percent had received no lead exposure training.
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Blood samples were collected from 581 of the 585 workers. Worker blood-lead
concentrations were generally low: 9.1 percent were above 10 |-ig/dL, 1.2 percent were above
25 |-ig/dL, and only one worker had a blood-lead concentration greater than 40 |_ig/dL. The
geometric mean blood-lead concentration for all workers was 4.5 |_ig/dL (see Figure 3).
However, there were significant differences among the worker groups that differentiate the
groups with the high mean blood-lead concentrations from those with the low mean blood-lead
concentrations. Drywall workers (6.1 |-ig/dL), painters (5.9 |-ig/dL), and window installers
(5.8 |-ig/dL) had the highest blood-lead concentrations, and floor layers (2.8 |_ig/dL) had the
lowest (see Table 3).
The results of statistical models developed and fit to the data indicated that, with the
exception of carpet removal, there was a statistically significant positive relationship between
worker blood-lead concentration and short-term conduct (days in the last 30 days) in pre-1950
houses for each target activity. The relationships between worker blood-lead concentration and
mid-term (weeks in the last year) and long-term exposure (years in career) associated with target
activities were also generally positive. After adjusting for other variables potentially related to
lead exposure — such as education level, smoking status, or age of worker's home — the data
suggested that activities such as general R&R, cleanup, and paint removal would result in
significant increases in worker blood-lead concentrations. However, in either the adjusted or
unadjusted models the estimated increases, while statistically significant, were generally so small
as to be of little practical consequence (see Table 4).
4.0 PHASE III: WISCONSIN CHILDHOOD BLOOD-LEAD STUDY
4.1 PHASE III: DESIGN
The third data collection effort of the R&R Study was the Wisconsin Childhood
Blood-Lead Study (Wisconsin R&R). The Wisconsin R&R Study was designed as a
retrospective case-control study to examine the association between incidence of R&R activities
and elevated childhood blood-lead levels (EBLs). The Wisconsin Bureau of Public Health's
Blood-Lead Registry was used to identify children with elevated blood-lead concentrations
(cases) and children that did not have elevated blood-lead concentrations (controls). Children,
both cases and controls, were selected from the registry, and questionnaire information was
obtained from a guardian of each selected child. The questionnaire obtained information on: the
child's residence, duration of residence, R&R activities in the past 12 months, blood sampling,
household information, adult occupations and hobbies, and household income. Target R&R
activities examined in the study included interior and exterior painting, paint removal and
surface preparation, window repair, carpet removal, and wall repair.
4.2 PHASE III: RESULTS
Analyses of the questionnaire and blood information collected indicated that general
residential R&R is associated with an increased risk of elevated blood-lead levels in children.
Specifically, children living in a residence where R&R was conducted in the last 12 months were
1.3 times more likely to have elevated blood-lead levels than children who did not live in a
residence where R&R was conducted.
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Specific R&R activities were also found to be associated with an increase in the risk of
elevated blood-lead concentrations among child occupants. In particular, removing paint (using
open flame torches, heat guns, chemical paint removers, and/or wet scraping/sanding) and
preparing surfaces by sanding or scraping significantly increased the risk of an elevated
blood-lead level (see Table 5). For example, when paint removal using a heat gun was
performed at a residence, the odds of an elevated blood-lead concentration were highly
significant (4.6 times greater) than if the work was not performed. (The odds were over 4 times
greater when compared to the case when some other type of surface preparation was carried out
and to the case when the effects of other R&R factors were taken into account).
Several other factors were also found to increase the risk of an elevated blood-lead level
in children. These factors included: increasing the number of rooms in which surface
preparation was carried out for inside painting, having a relative or friend not in the household
perform the R&R, living in the home while R&R was being conducted, and performing R&R in
the kitchen (see Table 5).
The questionnaire responses were also used to characterize the exposure of residents to
R&R activities. At least one R&R activity such as inside painting, outside painting, carpet and
floor repair or replacement, or other repairs (e.g., window repair) were conducted in 67.2 percent
of the study residences in the previous 12 months. Some form of surface preparation was
involved in 42.3 percent of R&R activities. Most surface preparation involved hand scraping or
sanding. Heat guns were used for surface preparation 7 percent of the time, and chemical paint
removers were used 13.6 percent of the time.
5.0 PHASE IV: WORKER CHARACTERIZATION AND BLOOD-LEAD STUDY
OF WORKERS AND HOMEOWNERS PERFORMING R&R IN HISTORIC HOMES
5.1 PHASE IV: DESIGN
The final data collection effort of the R&R Study was the Worker Characterization and
Blood-Lead Study of Workers and Homeowners Performing R&R in Historic Homes
(WCBS-HH). This study was designed as a follow-on study to Phase II of the R&R Study (the
WCBS). Like the WCBS, it involved collecting questionnaire and blood-lead measurements
from professional R&R workers to (1) characterize blood-lead concentrations in specific worker
groups, (2) determine if specific worker groups or specific R&R activities are associated with
increases in blood-lead concentrations, and (3) collect information to be used to develop worker
profiles. However, the WCBS-HH also collected similar information from homeowners
performing R&R themselves. Another difference from the Phase II study was that in either case
(homeowners or workers), information was obtained from populations believed to be at a
high-risk for lead-exposure because they routinely disturb lead-based paint; the data collection
was targeted to workers and homeowners performing R&R in older homes that are likely to
contain lead-based paint. Target R&R activities examined in the WCBS-HH included removal
of large structures (demolition), window replacement, carpet removal, paint removal/surface
preparation, and post-activity cleanup.
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5.2 PHASE IV: RESULTS
In all, questionnaires were collected from 246 participants (163 workers and
83 homeowners). The Phase IV questionnaire collected information on how often each
participant performed general R&R as well as specific target activities in historic homes.
Workers in Phase IV spent, on average, 21 days performing general R&R in historic homes
during the last 30 days. Homeowners spent, on average, 14 days performing general R&R in
their own historic or pre-1940 home. The responses to the questionnaires also indicate that:
1. Workers spent more time performing R&R than did homeowners.
2. Both workers and homeowners spent time performing a variety of R&R activities.
In particular, a large amount of time was spent performing large structure removal
and paint removal/surface preparation.
3. Sixty-three percent of workers and 43 percent of homeowners had used, at some
time in their career, a dust mask or respirator. However, on average, respirators
were used among homeowners or workers for only about half of the time spent
performing R&R during the last 30 days.
4. The majority of workers had not been trained (76%) nor received educational
information (67%) on lead exposure due to R&R work. Similarly, 62 percent of
homeowners had not received information on lead.
5. Over 75 percent of workers and homeowners who performed surface preparation
reported using dry sanding/scraping to remove paint. About one-third of
homeowners and workers reported using chemical stripping or burning/torching/
heat gun methods to remove paint.
Blood samples were collected from 161 workers and 82 homeowners. Overall, the
geometric mean blood-lead concentrations were well below 10 |_ig/dL: 5.7 |_ig/dL for workers
and 4.5 |_ig/dL for homeowners. Approximately 20 percent of the study participants had
blood-lead concentrations above 10 |_ig/dL. Also, 2.9 percent had blood-lead concentrations
above 25 |-ig/dL, and three study participants had blood-lead levels above 40 |_ig/dL (see
Figures 4 and 5). The adjusted geometric mean blood-lead concentrations among the worker
groups ranged from 4.2 |_ig/dL for Laborers to 6.3 |_ig/dL for Painters but were not found to be
significantly different (see Table 3). However, the adjusted geometric mean blood-lead
concentrations for workers were significantly greater than those for homeowners. Further, the
geometric mean blood-lead concentrations among high-risk workers (Phase IV) were
significantly higher than the geometric mean blood-lead concentrations of general workers
(Phase II) (see Table 3).
The results of statistical models developed and fit to the data indicated that there was a
significant relationship between the conduct of certain R&R activities and blood-lead
concentrations. Specifically, based upon covariate adjusted models, the number of days a
worker spent performing general R&R, paint removal/surface preparation, and cleanup were
significantly related to increases in worker blood-lead concentrations (see Table 6). Similarly,
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the number of hours that homeowners spent performing general R&R and paint removal/surface
preparation was found to be significantly related to increases in blood-lead concentrations (see
Table 7). However, as in Phase II, the estimated increases for workers or homeowners were
small.
6.0 CONCLUSIONS
The results of this study indicate that R&R workers may be exposed to high levels of
environmental lead while conducting certain activities in certain environments. However, there
was little evidence of elevated blood-lead concentrations2 in a population of general R&R
workers who conduct a wide variety of activities. Phase II of the R&R Study included workers
in cities with documented lead problems who were conducting a significant amount of work in
older buildings. In this regard, the results were weighted toward highly exposed general R&R
workers. However, only one out of 581 participating workers had a blood-lead concentration
greater than 40 |_ig/dL. Only seven out of 581 participating workers had a blood-lead
concentration greater than 25 |_ig/dL. There was evidence (Phase IV) that R&R workers who
may be even more highly exposed (i.e., workers specializing in historic renovations) had higher
blood-lead concentrations than workers surveyed in Phase II. However, Phase IV found that
even among these high-risk workers, only three out of 161 had blood-lead concentrations above
40 |-ig/dL. Further, out of 82 homeowners who performed R&R while residing in their own
historic/pre-1940 home, none had blood-lead levels above 40 |_ig/dL and only four had
blood-lead concentrations above 25 |_ig/dL.
Because low blood-lead concentrations were observed among R&R workers, long-term
occupant exposure should be stressed when determining the need for worker training,
certification, or educational materials. In this study, occupant exposure was characterized by
measuring lead levels in environmental dust and through a retrospective survey. Results from
Phase I of the study indicate that there is a potential for disturbing significant amounts of lead
during R&R activities which could result in occupant exposure if appropriate cleanup and
contamination practices are not conducted. The results of Phase III indicate that children
residing in homes where R&R activities were conducted are more likely to have elevated
blood-lead concentrations3 than children residing in homes where R&R was not conducted.
7.0 REFERENCES
U.S. Environmental Protection Agency (1997a) "Lead Exposure Associated With Renovation
and Remodeling Activities: Summary Report." Office of Pollution Prevention and Toxics,
U.S. Environmental Protection Agency, EPA 747-R-96-005, May 1997.
Elevated blood-lead concentrations among workers are defined for this study as concentrations
above 40 1-ig/dL, the current Occupational Safety and Health Administration (OSHA) level at
which full medical surveillance of a worker is required.
Elevated blood-lead concentrations among children are defined as concentrations equal to or
greater than 10 [ig/dL.
8
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U.S. Environmental Protection Agency (1997b) "Lead Exposure Associated with Renovation
and Remodeling Activities: Environmental Field Sampling Study." Office of Pollution
Prevention and Toxics, U.S. Environmental Protection Agency, EPA 747-R-96-007, May 1997.
U.S. Environmental Protection Agency (1997c) "Lead Exposure Associated with Renovation
and Remodeling Activities: Worker Characterization and Blood-Lead Study." Office of
Pollution Prevention and Toxics, U.S. Environmental Protection Agency, EPA 747-R-96-006,
May 1997.
U.S. Environmental Protection Agency (1998a) "Lead Exposure Associated with Renovation
and Remodeling Activities: Phase III, Wisconsin Childhood Blood-Lead Study" Office of
Pollution Prevention and Toxics, U.S. Environmental Protection Agency, EPA 747-R-99-002,
March 1999.
U.S. Environmental Protection Agency (1998b) "Lead Exposure Associated with Renovation
and Remodeling Activities: Phase IV, Worker Characterization and Blood-Lead Study of R&R
Workers Who Specialize in Renovation of Old or Historic Homes." Office of Pollution
Prevention and Toxics, U.S. Environmental Protection Agency, EPA 747-R-99-001,
March 1999.
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Table 1. Summary Measures of Worker Exposure to Airborne Lead (Phase I)
Number of
Workers
Monitored
Estimated
Geometric
Mean
Exposure11'
(Mg/m3)
95%
Confidence
Interval for
Geometric
Mean
Estimated
Percentage of
Workers With
Exposures
Expected to
Exceed 5O
Mg/m3(1)
95%
Confidence
Interval for the
Estimated
Percentage of
Workers
R&R Target Activities
Carpet Removal
Window Replacement
Paint Removal'2' (Hand)
(Power)
Large Structure Removal
(Interior Demolition)
HVAC Work
Surface (Interior)
Preparation'3'
(Exterior)
14
8
6
3
20
4
31
38
7.54
7.48
254.00
571.00
108.00
49.60
58.20
4.33
(1.74, 32.6)
(1.13, 49.3)
(23.7, 2720)
(42.9, 7600)
(26.6 435)
(11.4, 216)
(2.27, 1490)
(0.408, 46.0)
14%
6.5%
94%
99%
83%
48%
52%
11%
(3%, 43%)
(0%, 50%)
(41%, 100%)
(48%, 100%)
(40%, 99%)
(10%, 90%)
(23%, 80%
(0%, 49%)
Generic R&R Tasks'4'
Drilling into Wood
Drilling into Plaster
Sawing into Wood
Sawing into Plaster
7
6
6
2
15.10
6.76
546.00
110.00
(4.57, 50.2)
(3.00, 15.3)
(366, 813)
(0, 2. 32x1 06)
18%
0%
99%
76%
(4%, 51%)
(0%, 21%)
(99%, 100%)
(15%, 99%)
(1) Exposures represent the average lead exposure over the period in which the activity was conducted.
(2) Consists of continuous dry sanding activities (using hand or power methods).
(3) Based on data from other sources. Surface preparation consisted of a wide variety of activities including
wet and dry scraping, feathering of edges, and wet and dry sanding to prepare a surface for repainting.
(4) It could not be determined from this study how much of the difference between wood and plaster
substrates was due to differences in paint lead loading versus differences in substrate.
10
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Activity or Task
Sanding (Power)
Sawing into Wood
Sanding (Hand)
Sawing into Plaster
Demolition
Surface Prep - Interior
HVAC Work
Drilling into Wood
Carpet Removal
Window Replacement
Drilling into Plaster
Surface Prep - Exterior
1 —
These activities would not result in an
estimated geometric mean 8-hour TWA
greater than 50 [jg/rn3 based on the
observed data.
— i 1 1 1 1 1 1 —
— i 1 1 1 1 1 1
Figure 1. Hours of Activity That Would Result in an Estimated Geometric Mean
8-Hour TWA of 50 Mg/m3 (Phase I)
Table 2. Summary Measures of Potential Occupant Lead Exposures that Can Result from
Conducting Target and Generic R&R Activities (Phase I)
Average Lead Loading (Mg/ft2) in Settled I
(Measured Post-Activity, Before Cleanu
Estimated Loading in a 6'x1 ' Region
Extending from the Activity
Estimated Loading
at 6 Feet from
Activity
Just
J)
Standard Unit of Activity
Target Activity
Carpet Removal
Window
Replacement
Paint Removal
HVAC Work
Large Structure
Removal (Interior
Demolition)
16.9
7,710.0
42,900.0
1,290.0
3,250.0
(i)
482
15,500
414
1,530
100ft2
1 window
no standard unit of
activity
1 room
1 room
Generic Activity
Drilling into Wood
Drilling into Plaster
Sawing into Wood
Sawing into Plaster
432.0
34.5
999.0
328.0
1.27
0.04
105.00
10.60
10 holes
10 holes
1 linear ft
1 linear ft
(1) No samples were collected at six feet from the activity.
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Note: Results are based on conducting a standard unit of activity (see Table 6).
Figure 2. Estimated Distribution of Dust Lead in a 6' x 1' Region Extending from the
Activity Area for Various Activities (Phase I)
18
Q>
O
Q>
CL
15-
12-
9-
6-
3-
0
0.5
1.0 2.0 4.0 8.0 16.0 32.0 64.0
Blood —lead Concentration (/xg/'dL)
Figure 3. Histogram of Blood-Lead Concentration (Semi-Logarithmic Scale) for
Workers in the WCBS (Phase II)
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Table 3. Information for an Assessment of Worker Exposures Associated with Different
R&R Worker Groups (Phases II and IV)
Study
WCBS
(Phase II)
WCBS-HH
(Phase IV)
Worker
Group
Union
Carpenters
Non-Union
Carpenters
Floor Layers
Laborers
Supervisors
Painters
Dry wall
Workers
Window
Replacement
Workers
Carpenters
Laborers
Painters
Other
Workers
Homeowners
That Perform
R&R
# Workers
Monitored
159
105
82
56
57
34
64
14
47
42
44
26
82
MEASURES OF WORKER EXPOSURES
Geometric Mean
Blood -Lead
Cone. (|Jg/dL)
4.5
4.8
2.8
4.1
4.1
5.9
6.1
5.8
6.1
4.2
6.3
5.0
4.4
95% Confidence
Interval on
Geometric Mean
(4.1, 5.0)
(4.3, 5.4)
(2.5, 3.2)
(3.5, 4.9)
(3.5, 4.8)
(4.8, 7.3)
(5.3, 7.1)
(4.3, 7.9)
(5.1, 7.4)
(3.5, 5.1)
(5.1, 7.7)
(3.9, 6.4)
(3.7, 5.2)
Percentage
That Used a
Respirator'1'
4
12
7
23
5
21
2
14
28
16
30
16
16
Percentage
That Received
Some Lead
Training
9
16
9
16
23
21
6
14
30
9
32
18
N/A
(1)
Does not include wearing dust masks.
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Table 4. Predicted Changes in General Worker Blood-Lead Concentrations Associated
with 10 Days of Work in Pre-1950 Buildings (Phase II)
Target Activity
Carpet Removal
Window
Replacement
Paint Removal
HVAC Work
Large Structure
Removal
Cleanup
General R&R
Based on Model Unadjusted for
Covariates
Level When Worker
Base « Conducts an Additional 10
Level Days per Month of Activity
4.4 -» 4.9
4.2 -» 5.1*
4.1 -»5.2*
4.4 -» 5.6*
4.2 -» 4.8*
4.1 -»4.7*
3.7 -» 4.4*
Based on Covariate Adjusted Model
Level When Worker Conducts
Base . an Additional 10 Days per
Level Month of Activity
4.5 -» 4.1
4.4 -» 4.8
4.3 -» 4.8*
4.4 -» 4.7
4.3 -» 4.7
4.3 -» 4.6*
3.9 -» 4.4*
Slope parameter estimate was significant at an alpha = 0.05 level.
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Table 5. Unconditional Odds Ratios from Logistic Regression with Single R&R Variables
(Phase III)
Variable a
Any R&R Work
Inside Painting
Window Repair or
Replacement
Inside or Outside Painting
Prepared Surface
Prepared Surface for Inside
Painting
Hand Sanding or Scraping
Power Sanding, Grinding,
Sandblasting
Open Flame Torch
Heat Gun
Washing, Wetscraping,
Water Blasting
Chemical Paint Removers
Higher Risk
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Lower Risk
No
No
No
No
No
No
No
No
No
No
No
No
P-Value
0.0220*
0.9267
0.4652
0.0116*
0.0038*
0.0645
0.1158
0.1035
0.01018*
< 0.0001*
0.0092*
0.0046*
Odds Ratio"
1.309
1.010
1.095
1.322
1.430
1.325
1.226
1.372
4.883
4.597
1.625
1.969
Confidence
Interval
(1.035,1.656)
(0.814,1.252)
(0.855,1.402)
(1.060,1.649)
(1.117,1.830)
(0.977,1.796)
(0.946,1.588)
(0.930,2.025)
(1.423,16.759)
(2.715,7.782)
(1.119,2.360)
(1.220,3.176)
Who Did the Work?
Head of the Household or
Spouse
Other in Household
Relative or Friend Not in
Household
Owner or Apartment Staff
Professional
Yes
No
Yes
Yes
Yes
No
Yes
No
No
No
0.1696
0.0355*
0.0015*
0.4787
0.1195
1.214
3.000
2.231
1.244
1.490
(0.915,1.611)
(1.055,8.531)
(1.344,3.705)
(0.672,2.305)
(0.893,2.486)
Lived in Home While R&R
Was Done
Number of Rooms
R&R Work in Kitchen
Yes
1 c
Yes
No
Oc
No
O.O1638*
0.0007*
0.0243*
1.365
1.119
1.569
(1.054,1.769)
(1.047,1.197)
(1.052,2.340)
Note: Shaded area (and asterisk) indicates statistically significant results
(a) If the answer to any of the following questions was "Yes", this indicator variable was set to 1.
(b) The odds ratio compare the odds of a child having elevated blood-lead concentrations when a particular R&R activity
occurred against the odds of a child having elevated blood-lead concentrations when the particular R&R activity did not
occur.
(c) "Number of Rooms" was included as an ordinal variable. The risk groups were chosen for illustration. More generally,
the odds ratio between n + k and n rooms is 1.119k.
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Table 6. Predicted Changes in High-Risk Worker Blood-Lead Concentrations (|Jg/dL)
Associated with 10 Days of Work in Pre-1940 Homes (Phase IV)
Target Activity
Large Structure
Removal
Paint Removal/
Prepare Surface
Window/ Door
Casement
Removal
Carpet Removal
Cleanup
General R&R(a)
Based on Model Unadjusted for Covariates
Level When Worker
Base Conducts an Additional 1 0
Level(a) -t Days per Month of Activity
5.6 -4 5.7
4.8 -4 5.5*
5.2 -4 6.1*
5.9 -4 5.3
4.5->5.3*
3.8->5.5*
Based on Covariate Adjusted Model
Level When Worker
Base Conducts an Additional 1 0
Level'3' ^ Days per Month of Activity
5.7 -4 5.7
4.7 -4 5.4*
5.3 -4 6.0
5.8 -4 5.4
4.4-»5.2*
4.0-»5.5*
(a) The Base Level for General R&R is 10 days, for all other activities the Base Level is zero days.
* Slope parameter estimate for days per month of activity was significant at the alpha = 0.05 level.
Table 7. Predicted Changes in Homeowner Blood-Lead Concentrations (|Jg/dL) Associated
With Changes in the Number of Hours Spent Performing a Target Activity in
Their Pre-1940 Home (Phase IV).
Target Activity
General R&R
Large Structure
Removal
Paint Removal/
Prepare Surface
Window/ Door
Casement Removal
Carpet Removal
Cleanup
Additional
Number of
Hours**
80
14
36
6
2
25
Based on Model Unadjusted for
Covariates
Level When
Homeowner Conducts
Base Additional Hours per
Level(a) -» Month of Activity
3.0 -» 4.5*
4.6 -44.5
3.4-» 4.5*
4.5 -44.5
4.5-»4.5
4.7 -44.5
Based on Covariate Adjusted Model
Level When
Homeowner Conducts
Base Additional Hours per
Level(a) •* Month of Activity
3.1 -44.5*
4.3-»4.4
3.5 -44.4*
4.3-»4.4
4.4-»4.4
4.2-»4.4
(a) The Base Level is zero hours for all comparisons.
* Slope parameter estimate for days per month of activity was significant at the alpha = 0.05 level.
** The number of hours is based upon the average number of hours homeowners spent performing the target activity in
their home during the last 30 days.
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