EPA
No. 747-R-97-005

December 1997
                      LEAD-BASED PAINT ABATEMENT AND
                       REPAIR AND MAINTENANCE STUDY
                                 IN BALTIMORE:

                FINDINGS BASED ON TWO YEARS OF FOLLOW-UP
                                  Technical Branch
                         National Program Chemicals Division
                       Office of Pollution Prevention and Toxics
                  Office of Prevention, Pesticides, and Toxic Substances
                         U.S. Environmental Protection Agency
                                  401 M Street, SW
                               Washington, DC 20460
           Recycled/Recyclable $ Printed with Vegetable Based Inks on Recycled Paper (20%
                                    Postconsumer)

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EXECUTIVE SUMMARY

       In recent years, there has been growing interest in the use of
interim measures to temporarily control the problem of extensive
residential lead-based paint hazards in U.S. housing in a cost-
effective manner. Title X of the Housing and Community
Development Act
of 1992 (P.L. 102-550) defined interim controls as "a set of measures
designed to reduce temporarily human exposure or likely exposure to
lead-based paint hazards, including specialized cleaning, repairs,
maintenance, painting, temporary containment, ongoing monitoring
of lead-based paint hazards or potential hazards and the
establishment of management and resident education programs."
The 1995 Guidelines for the Evaluation and Control of Lead-Based Paint Hazards in
Housing issued by the U.S. Department of Housing and Urban
Development (HUD) provide detailed information on interim control
practices. However, little is known about the short-  and long-term
effectiveness of these approaches in terms of reducing lead in dust
and in children's blood.

       This report presents two years of follow-up of the Lead-Based
Paint  Abatement and Repair & Maintenance (R&M) Study in
Baltimore.  An earlier report presented results for the first year of
follow-up (EPA, 1997). The study was designed to characterize and
compare the short-term (two months to six months) and longer-term
(12 months to 24 months) effectiveness of three levels of interim
control interventions (R&M I-III) in structurally sound housing
where children were at risk of exposure to lead in settled house dust
and paint. At the time of this study, owners were not required to
reduce lead exposure in their rental properties prior to children
becoming poisoned. Thus,  study houses received R&M interventions
that they were not likely to have gotten otherwise. Funds for R&M
work  provided by the Maryland Department of Housing and
Community Development were capped at $1,650 for R&M I, $3,500
for R&M II, and $7,000 for R&M III.

       R&M I included wet scraping of peeling and flaking lead-based
paint  on interior surfaces; limited repainting of scraped surfaces; wet
cleaning with a trisodium phosphate (TSP) detergent and vacuuming
with a high efficiency particulate air (HEPA) vacuum to the extent
possible in an occupied house; the provision of an entryway mat and
information to occupants; and stabilization of lead-based paint on
exterior surfaces to the extent possible, given the budget cap. R&M
II included two key additional elements: use of sealants and paints to

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make floors smoother and more easily cleanable and in-place
window and door treatments to reduce abrasion of lead-painted
surfaces. R&M III added window replacement and encapsulation of
exterior window trim with aluminum coverings as the primary
window treatment, encapsulation of exterior door trim with
aluminum,  and the use of coverings (e.g., vinyl tile) on some floors
and stairs to make them smooth and more easily cleanable.
Additionally, all R&M households received cleaning kits for their
own cleaning efforts. During follow-up, families were informed by
letter of the results of dust lead and blood lead tests from each
campaign (Appendix A).

       For this reason, the study intervention was a combination of
R&M work and the provision of information to families on a
periodic basis. Further, as required by Maryland law, all blood lead
results were reported to the Maryland Childhood Blood Lead
Registry which in turn reported the results to the Baltimore City
Health Department for follow-up and case management.  Thus, this
study add to, but did not replace usual medical care.

       The study had two control groups: urban houses built after
1979, and presumably free of lead-based paint, and previously
abated houses which had received comprehensive abatement
between May 1988 and February 1991. For ethical reasons, the study
did not include a non-intervention control group of houses that
contained lead-based paint hazards.

       The study population consisted of Baltimore households with at
least one participating child  that occupied or moved into study
houses owned by collaborating rental property owners and a non-
profit housing organization.  All households were African-American
and reflected the demographic composition of neighborhoods where
collaborating owners managed their properties. At the outset, mean
ages of study children ranged from 25 to 34 months across groups,
and their geometric mean blood lead concentrations were 9 |ig/dL in
R&M I, 13 |ig/dL in R&M II, 14 |ig/dL in R&M III, and 12 |ig/dL in
the previously abated houses. Based on reported housing histories,
children in these four groups had spent most or all of their lives in
older low-income rental housing and thus had been at risk of
exposure to lead in dust and paint.  By contrast, most children in the
modern urban group had lived in the same house since birth, and all
of them had baseline blood lead concentrations less than or equal to
the CDC's  blood level of concern (10 |ig/dL). Their baseline
geometric  mean blood lead concentration was 3 |ig/dL, a value
similar to that estimated for  U.S. children in this age range (2.7
|ig/dL) but lower than the estimate for U.S.  non-Hispanic black
children 12 months to 60 months of age (4.3 |ig/dL) (CDC, 1997b).

       Study objectives related to enrollment, laboratory performance,

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data quality and data completeness were met.  The main findings
based on dust lead loadings and concentrations, dust loadings, and
children's blood lead concentrations from the five study groups
collected before and immediately after intervention, as well as
during the two-, six-, 12-, 18-, and 24-month post-intervention data
collection campaigns are summarized below.

Main Findings Related to Dust Lead Loadings and Concentrations
and Dust Loadings

       Median dust lead loadings and concentrations based on floor,
window sill and window well surfaces are displayed in Figure ES-1
and Table ES-1 to provide a sense of the overall magnitude of house
dust lead levels over time within and between groups.  Among R&M
groups, pre-intervention dust lead loadings tended to be highest in
vacant R&M III houses, lowest in occupied R&M I houses, and
intermediate in R&M II, which was a mix of vacant and occupied
houses.

      All three levels of R&M intervention were associated with
       statistically significant reductions in house dust lead loadings
       and total dust loadings that were sustained below pre-
       intervention levels during two years of follow-up. Dust lead
       concentrations were significantly reduced following
       intervention in the middle level (R&M II) and high level
       (R&M III) intervention houses, but not in the low level
       intervention houses (R&M I). Further, the three levels of R&M
       interventions did not reduce lead loadings, lead concentrations,
       and dust loadings to the same extent.
*
   Overall median values are summary measures based on combined
R&M cyclone dust data across floors, window sills, and window wells
within a house, weighted by surface area sampled. (Month O=Baseline;
PI=Immediately Post Intervention; Abated=Previously Abated between
5/1988 and 2/1991).

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      Figure ES-1: Overall Median Dust Lead Loading (PbD) by Group"
       100000
    0)
    3
    Q
    &
    0_
        10000
1000
                          	   R&M I	R&M II
                          	   Modern    	   Abated
                                                          R&M
           100
                0  PI  2
                                       12
                              Campaign (month)
18
24
      When interpreting Figures ES-1 to ES-4 some caveats should
be noted. First, the overall summary measure plotted in Figure ES-1
is not directly comparable to HUD interim clearance standards and
EPA clearance standard guidance for lead in house dust, both of
which are surface specific (floors: 100 |ig/ft2; window sills: 500 jig/ft
2;  window wells: 800 |ig/ft2) and based on wipe samples. The median
values in Figures ES-2 to ES-4 are also not directly comparable to
clearance standards for lead in house dust due to the sampling
method used. Data at immediately post-intervention (PI) and at two-
months post-intervention are relevant to the three R&M groups only.
The median values presented in Figures ES-1 to ES-4 are not
adjusted for season or other covariates or potential effect modifiers.

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  Table ES-1: Overall Median Dust Lead Loadings (//g/ft2), Lead Concentrations (//g/g)
and          Dust Loadings (mg/ft2) by Group for Selected Campaigns *
Measure
and Group
Lead Loading:
R&MI
R&MII
R&M III
Prev.
Modern
Lead Cone.:
R&MI
R&MII
R&M III
Prev.
Modern
Dust Loading:
R&MI
R&MII
R&M III
Prev.
Modern
Baseline

16,150
25,930
51,210
1,050
90

18,790
16,830
22,010
2,430
210

940
1,610
2,510
290
400
Post-
Intervent
ion

1,580
270
70
n/a
n/a

7,990
6,910
2,650
n/a
n/a

140
40
30
n/a
n/a
2
Months

3,760
1700
200
n/a
n/a

16,800
10,970
1,530
n/a
n/a

260
160
130
n/a
n/a
12
Months

3,300
1,020
160
370
60

16,150
5,600
1,080
3,010
310

250
220
140
220
140
24
Months

3,320
960
120
210
40

8,700
6,340
890
1,130
290

260
200
130
190
140
       Overall median values are summary measures based on combined
       R&M cyclone dust data across floors, window sills, and window
       wells within a house, weighted by surface area sampled.
n/a = not applicable

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Main Dust Findings (cont.)
       Immediately after intervention and during two-years of follow-
       up, dust lead loadings, lead concentrations and dust loadings
       were lowest in R&M III houses, intermediate in R&M II
       houses, and highest in R&M I houses (Figure ES-1; Table ES-
       1). For example, at 24 months, overall median lead loading
       estimates were 27 times higher in R&M I houses than in R&M
       III houses, and eight times higher in R&M I houses than in
       R&M II houses. Statistically significant differences were found
       between R&M groups on the two dust lead measures over time.
       Differences in lead loadings between R&M groups were
       primarily due to differences in lead concentrations and
       secondarily to differences in dust loadings.

       Surface-specific data for lead loadings and concentrations show
       that the differences between R&M groups after intervention
       were most pronounced for window wells and window sills as
       compared to floors (Figures ES-2 - ES-4; Tables ES-2 - ES-3).
       Moreover, across groups and time, window wells had the
       highest lead loadings, floors the lowest, and window sills were
       intermediate.

       Reaccumulation of dust and dust lead loadings in all three
       R&M groups was the greatest during the first two months after
       intervention, while there was relatively little reaccumulation
       between two months and 24 months post-intervention (Figures
       ES-l-ES-4).

       The modern urban control group had significantly lower dust
       lead loadings and concentrations across time than the other four
       groups (Figures ES-1 - ES-4, Tables ES-1 and ES-2). These
       houses, located in clusters of urban houses built after  1979,
       were expected to reflect the lowest residential and ambient lead
       levels in the urban environment. Low dust lead concentrations
       (overall medians <400 jig/g, equivalent to <0.04 percent) and
       drip-line soil lead concentrations (geometric means <70 |ig/g)
       support the assumption that these houses were free of lead-
       based paints. Dust lead levels in the previously abated control
       houses four years to  six years post-abatement were generally
       similar to those in R&M III houses at the end of the second
       year of follow-up (Figure ES-1).

       No evidence was found for selection bias when R&M study
       houses were compared to houses that were considered for study
       but later rejected, mainly due to lack of timely cooperation with
       the loan process, family moves and safety concerns.

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D)
3-

Q
.a
Q.
      Figure ES-2: Median Floor Dust Lead Loading by Group
    10000
     1000
100
          0 PI 2
                        R&M I    

                        Modern   
                              R&M II

                              Abated
  R&M
                              12
                       Campaign (month)
18
24

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  Figure ES-4: Median Window Well Dust Lead Loading by Group

  1000000
 0)
3

Q
&
0_
   100000
    10000
 1000
      100
                  	  R&M I	R&M II

                  	  Modern   	 Abated
                                              R&M
l../r
  /	
           0  PI  2
                               12

                        Campaign (month)
                                     18
24
   Figure ES-3: Median Window Sill Dust Lead Loading by Group

   100000
CM


O)
D
.a
0_
    10000
1000
                 	  R&M I	R&M II

                 	   Modern   	  Abated
                                              R&M
 100
          0  PI 2
                               12

                        Campaign (month)
                                     18
24

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Main Findings Related to Children's Blood Lead Concentrations

      Using all five study groups in the longitudinal data analysis, a
       statistically significant relationship was found between a
       composite measure of house dust lead in an entire house (both
       concentration and loading) and children's blood lead
       concentration, controlling for age and season.

      Children in the modern urban group had significantly lower
       blood lead concentrations than children in each of the other
       four groups (Table 22); their blood lead concentrations were
       <10 //g/dL, the Center for Disease Control's level of concern
       (Figure 17).

      Children with baseline blood lead concentrations > 15/dL in
       each of the three R&M groups and the previously abated group
       had statistically significant reductions in blood lead
       concentration during follow-up, after controlling for age,
       gender and season (Table 23).
Table ES-2:  Median Dust Lead Loadings (//g/ft2) by Surface Type and by R&M Group
         for Selected Campaigns
Surfac
e
Type
Floor


Window
Sill

Window
Well

Group
R&M
R&M
R&M
R&M
R&M
R&M
R&M
R&M
R&M
Pre-
Interven
tion
370
910
4,780
4,800
9,560
21,670
187,170
273,980
420,970
Post-
Intervent
ion
330
230
35
500
160
10
10,760
380
60
2
Months
110
120
150
740
260
60
24,250
7,150
370
12
Months
90
90
70
1,180
420
40
24,970
5,080
330
24
Months
90
70
60
510
330
40
21,530
3,590
280

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Table ES-3:  Median Dust Lead Concentrations (//g/g) by Surface Type and by R&M
              Group for Selected Campaigns
Surfac
e
Type
Floor


Window
Sill

Window
Well

Group
R&M
R&M
R&M
R&M
R&M
R&M
R&M
R&M
R&M
Pre-
Interven
tion
2,050
2,850
4,070
16,890
15,260
14,860
27,960
22,430
21,680
Post-
Intervent
ion
1,460
3,250
1,840
16,620
8,030
617
25,624
13,390
2,040
2
Months
770
1,200
850
8,740
6,600
1,020
32,190
12,750
1,560
12
Months
750
720
560
10,100
4,500
630
26,840
7,450
1,220
24
Months
740
700
600
9,940
3,260
830
23,330
8,970
1,250
Main Blood Lead Findings (conf).

      Overall, children in the three R&M groups with baseline blood
       lead concentrations <15 |ig/dL had a statistically significant
       reduction in blood lead concentration over time, when
       controlling for age, gender and season (e.g., the predicted blood
       lead concentration at 24 months was on average 20 percent
       lower than the baseline level).  However, no statistically
       significant differences in predicted blood lead concentration
       were found between and within individual  R&M groups during
       the two years of follow-up, controlling for age, gender and
       season (Table 22).  Cumulative body lead burden,
       neighborhood housing characteristics and age at start of study
       are discussed as factors that may have mediated children's
       blood lead responses to the R&M interventions and contributed
       to the differences in blood lead concentrations observed
       between children in the modern urban group and those in the
       other four groups.

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       Across groups, most children who reached the age of six
       months during follow-up had blood lead concentrations
       <10//g/dL, the CDC level of concern, despite increases in blood
       lead concentration over time (Figure 19). The small number
       (n=16) of such children precluded further data analysis,
       however they add to our understanding of the potential role of
       R&M interventions in the primary prevention of lead
       poisoning.
       It should be emphasized that the R&M interventions under
investigation are interim control or partial abatement approaches to
reducing lead-based paint hazards. As such, they are not expected to
be as long-lasting as lead-based paint abatement work. During the
first two years of follow-up, none of the interventions in individual
houses failed, that is, all or most of the dust samples showed lead
loadings at, or below, pre-intervention levels. Thus,  a major study
objective with important policy implications remains the
documentation of the longevity of the R&M interventions. Toward
this end, the study has been extended to five years of follow-up with
funding from HUD. Lastly, it is important to recognize that the
costs of the interventions in this study may not be generalizable to
other settings and time periods.

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