The prevalence of lead-based paint hazards in U.S. housing. (Children's Health Articles).

In this study we estimated the number of homing units in the United States with lead-based paint and lead-based paint hazards. We included measurements of lead in intact and deteriorated paint, interior dust, and bare soil. A nationally representative, random sample of 831 housing units was evaluated in a survey between 1998 and 2000; the units and their occupants did not differ significantly from nationwide characteristics. Results indicate that 38 million housing units had lead-based paint, down from the 1990 estimate of 64 million. Twenty-four million had significant lead-based paint hazards. Of those with hazards, 1.2 million units housed low-income families (< $30,000/year) with children under 6 years of age. Although 17% of government-supported, low-income homing had hazards, 35% of all low-income homing had hazards. For households with incomes [greater than or equal to] $30,000/year, 19% had hazards. Fourteen percent of all houses had significantly deteriorated lead-based paint, and 16% and 7%, respectively, had dust lead and soil lead levels above current standards of the U.S. Department of Housing and Urban Development and the U.S. Environmental Protection Agency. The prevalence of lead-based paint and hazards increases with age of housing, but most painted surfaces, even in older homing, do not have lead-based paint. Between 2% and 25% of painted building components were coated with lead-based paint. Housing in the Northeast and Midwest had about twice the prevalence of hazards compared with housing in the South and West. The greatest risk occurs in older units with lead-based paint hazards that either will be or are currently occupied by families with children under 6 years of age and are low-income and/or are undergoing renovation or maintenance that disturbs lead-based paint. This study also confirms projections made in 2000 by the President's Task Force on Environmental Health Risks and Safety Risks to Children of the number of houses with lead-based paint hazards. Public- and private-sector resources should be directed to units posing the greatest risk if future lead poisoning is to be prevented. Key words: childhood lead poisoning, housing, housing survey, lead, lead-based paint, lead paint, lead poisoning prevention. Environ

Health Perspect 110:A599-A606 (2002). [Online 13 September 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110pA599-A606jacobs/abstract.html

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Lead is highly toxic, especially to young children. Excessive exposure causes reduced intelligence, impaired hearing, reduced stature, and many other adverse health effects (NAS 1993). The effects of lead toxicity have been well established, with clear evidence of harm found in children whose blood lead levels are above 10 [micro]g/dL and some evidence that harm may occur at lower levels (CDC 1991; Lanphear et al. 2000; NAS 1993; Schwartz 1994; U.S. EPA 1990). A large body of evidence shows that a common source of lead exposure for children today is lead-based paint hazards in older housing and the contaminated dust and soil it generates (Bornschein et al. 1987; Clark et al. 1991; Jacobs 1995; Lanphear et al. 1995, 1998; Lanphear and Roghmann 1997; McElvaine et al. 1992; Rabinowitz et al. 1985; Shannon and Graef 1992), although other sources can be significant. Poisoning from lead-based paint has affected millions of children since this problem was first recognized more than 100 years ago (Gibson 1904; Turner 1897).

Children are exposed to lead from paint through two major pathways: either directly by eating paint chips (McElvaine et al. 1992) or indirectly by ingesting lead-contaminated house dust or soil through normal hand-to-mouth contact (Bornschein et al. 1987; Duggan and Inskip 1985; Lanphear and Roghmann 1997). Recent studies indicate that dust lead is the strongest predictor of childhood blood lead levels (Duggan and Inskip 1985; Lanphear et al. 1998). Unless proper precautions are implemented, lead-based paint can contaminate dust or soil when it deteriorates or is disturbed during maintenance, repainting, remodeling, demolition, or paint removal (Lanphear and Rogmann 1997; Rabinowitz et al. 1985; Shannon and Graef 1992). Residences with deteriorated lead-based paint are more likely to have higher levels of lead in house dust and the surrounding soil (Jacobs 1995; U.S. EPA 1995; U.S. HUD 1990).

Although lead in new residential paint was banned in the United States in 1978 by the Consumer Product Safety Commission (U.S. CPSC 1977a, 1977b; U.S. HUD 1997), a previous study conducted by the U.S. Department of Housing and Urban Development (HUD) in 1990 showed that lead-based paint still remained in an estimated 64 million dwelling units (U.S. EPA 1995; U.S. HUD 1990).

Recent studies of residential lead hazard controls have evaluated strategies that combined measures to remove and/or repair deteriorated lead-based paint, along with other measures to reduce and prevent reaccumulation of lead in dust. These treatments resulted in substantial and sustained reductions in interior lead dust and children's blood lead levels (Farfel et al. 1994; Galke et al. 2001; U.S. EPA 1997).

This study is part of the National Survey of Lead and Allergens in Housing and provides recent estimates of lead contamination in U.S. housing. It is part of a study that examines not only lead contamination but also allergen and endotoxin levels in U.S. housing. The allergen and endotoxin survey methodology has been published separately (Vojta et al. 2002).

Methods

The target population for this study consisted of the national housing stock of permanently occupied, noninstitutional housing units, including multifamily buildings, single-family housing, and manufactured housing (mobile homes) in all 50 states and the District of Columbia. Vacant housing, group quarters (e.g., prisons, hospitals, dormitories), hotels, motels, and other short-term housing, military bases, and housing where children are not permitted to live (e.g., housing designated exclusively for the elderly and those with zero bedroom units) were excluded. With these excluded, the eligible national housing stock consisted of approximately 96 million housing units out of approximately 112 million units. A nationally representative, random sample of 1,984 housing units was drawn from 75 randomly selected primary sampling units (PSUs), from which 831 eligible units and their occupants were recruited and completed the survey. (A PSU is a county or a cluster of contiguous counties, such as a metropolitan statistical area.) Documentation on using the data, and the data files themselves, are available at the HUD lead web site (U.S. HUD 2001, 2002). A comparison of the units in the study with national distributions of housing characteristics and socioeconomic and demographic factors from the 1997 American Housing Survey for the United States (U.S. Census Bureau 1997) and the 1998 and 1999 Current Population Surveys (U.S. Census Bureau 1999) showed that the units in this study did not differ significantly from nationwide characteristics (Table 1). Although the percentage of households in the sample with incomes below $20,000 and above $60,000 are both slightly below national estimates, the percentage of households in poverty is very close to the national estimates. It is possible that households with very low incomes (where the risk of lead poisoning is greatest) and with very high incomes (where the risk is lowest) may have been slightly undersampled.

A stratified sample of four rooms within each unit was drawn according to the following priorities: child's bedroom, common living area within the unit, kitchen, and one other random room. If no child's bedroom was present, another bedroom was selected according to a standard protocol. Table 2 presents the type and location of dust and soil samples and paint measurements made in each room, from the building exterior, and in the yard. Soil samples were collected from children's play areas at 375 homing units in 40 of the original 75 PSUs, and general yard samples were collected in all 75 PSUs. The 40 PSUs were randomly selected from the original 75 PSUs. Play area and yard area soil lead hazards are both included in the estimates of lead-based paint hazards reported here (see definition of "lead-based paint hazard" below). Weights were developed for housing units, rooms, yards, and exterior play yard areas to be nationally representative.

A standardized questionnaire was administered to an adult resident in each unit to determine age and renovation history of the unit; occupants' age, race and ethnic group, occupation, hobbies, and smoking patterns; household cleaning schedules; type of housing; types of heating, ventilating, and air conditioning systems; types of flooring; presence of pets; presence of pests; occupant income; government housing support; and other information. The responses to the questions on household size and income were used to apply the 1996 U.S. Census Bureau poverty thresholds (U.S. Census Bureau 1996) to determine whether or not a household was in poverty. The Census Bureau poverty income thresholds vary with household size.

Single-surface dust wipe samples were collected from floors, interior windowsills, and window troughs in accordance with the method in American Standards for Testing Materials (ASTM) E1728-95(ASTM 1995b). Paint measurements were made in a nondestructive manner using portable X-ray fluorescence (XRF) lead-based paint analyzers, in accordance with HUD procedures and the applicable Performance Characteristic Sheet (U.S. HUD 1997). A single commercial-brand of XRF instrumentation was used to minimize analytical error. Building components were tested in accordance with a standard procedure (Table 3). Soil samples were collected from the following areas: main entry, foundation/drip line, mid-yard area, and play areas (identified by the presence of play equipment or report from the adult occupant); if present, bare soil was sampled preferentially. Soil sampling was conducted in accordance with the method in ASTM E1727-95 (ASTM 1995a) using a core sample of the top one-half inch of soil, which is most accessible to children. All samples were collected by certified lead-based paint inspectors and analyzed in laboratories recognized under the National Lead Laboratory Accreditation Program of the U.S. Environmental Protection Agency (U.S. EPA) and accredited by the American Industrial Hygiene Association Environmental Lead Laboratory Accreditation Program. Detailed quality control/quality assurance protocols, laboratory analytical techniques, data management procedures, and a discussion of other potential sources of error (e.g., nonresponse bias and random sampling) have been reported elsewhere (U.S. HUD 2001).

Fieldwork for this survey was conducted between 1998 and 2000, with most units sampled during the warmer months. Dust lead levels may be slightly higher in the warmer months, due to increased track-in or other factors. Data presented here are not controlled for seasonal effects.

In this article, the term "lead-based paint hazard" is defined in the same way as in U.S. HUD and U.S. EPA regulations (U.S. EPA 2001; U.S. HUD 1999) (Table 4). A "significant lead-based paint hazard" means the area of deteriorated lead-based paint is above the de minimis levels (Table 5, note a) specified in the HUD regulations (U.S. HUD 1999) and/or that interior floor or windowsill dust lead or soil lead in the yard or play area meets or exceeds the levels established by the U.S. EPA. "Lead-based paint" is a paint or coating with a lead content [greater than or equal to] 1 mg/[cm.sup.2] or 0.5% by weight (the same definition used in Title X of the 1992 Housing and Community Development Act, also known as the Residential Lead-Based Paint Hazard Reduction Act).

Results

Hazards. The results show that an estimated 25% of the nation's housing (equivalent to 24 million housing units) had significant lead-based paint hazards in the form of deteriorated paint, dust lead, or bare soil lead. The prevalence rates of significantly deteriorated lead-based paint and dust lead hazards were about the same--14% and 16%, respectively. Only 7% of houses had soil lead levels above current U.S. EPA/HUD standards (U.S. EPA 2001; U.S. HUD 1999) (Table 4).

The prevalence of lead-based paint hazards varies by region, housing unit age, household income, and other factors (Table 5). Of the units with significant lead-based paint hazards, an estimated 1.2 million units were occupied by low-income families (< $30,000/year) with children under 6 years of age. Among low-income households, 35% of the units had lead-based paint hazards, compared with 19% of units among households with middle and upper incomes ([greater than or equal to] $30,000/year). Seventeen percent of government-assisted, low-income housing had lead-based paint hazards, which is about the same as that for middle- and upper-income housing.

The prevalence of units with significant hazards varies with age of housing and region (Table 5), but less so with degree of urbanization. Housing built before 1960 had five to eight times the prevalence of hazards compared with units built between 1960 and 1978. Approximately 36% of the housing in the Northeast and Midwest had lead-based paint hazards, compared with about 16% of housing in the South and West. Surprisingly, units in large urban and small urban and rural areas had roughly the same prevalance of lead-based paint hazards (~27%).

Rental units also had a slightly higher prevalence of lead-based paint hazards compared with owner-occupied units (30% and 23%, respectively).

This study also examined for the first time the prevalence of lead-based paint hazards in housing built after lead paint was banned in 1978. Among housing built between 1978 and 1998, 3% (1,042,000 housing units) had significant lead-based paint hazards, but 7% (2,031,000 housing units) may have had lead-based paint. (More than half of the XRF measurements above 1.0 mg/[cm.sup.2] in these newer units were on painted tile or stone substrates and are therefore uncertain because the lead may be in the substrates themselves, not the paint.)

Interior dust lead hazards. An estimated 16% of all housing units nationwide (equivalent to 15.5 million units) had one or more lead dust hazards on either floors or windowsills (Table 4). The geometric mean dust lead level for floors, window sills, and window troughs was 1.1 [micro]g/[ft.sup.2], 9.4 [micro]g/[ft.sup.2] and 96.4 [micro]g/[ft.sup.2], respectively (Table 6). The arithmetic means (used for composite dust sampling) for these surfaces were 13.6 [micro]g/[ft.sup.2], 195 [micro]g/[ft.sup.2], and 1,991 [micro]g/[ft.sup.2], respectively. These can be compared with the current U.S. EPA/HUD dust lead hazard or clearance standards for these surfaces, which are 40 [micro]g/[ft.sup.2], 250 [micro]g/[ft.sup.2], and 400 [micro]g/[ft.sup.2], respectively (U.S. EPA 2001; U.S. HUD 1999).

Dust lead hazards are more likely to exist in homes with significantly deteriorated interior lead-based paint. Although only one-third of homes with interior lead-based paint in good condition had dust lead hazards, nearly two-thirds of the homes with deteriorated interior lead-based paint had dust lead hazards (Table 7). Based on our results, of the 24 million units with lead-based paint hazards, 2.7 million units with no lead-based paint on either the interior or exterior at the time of the survey have dust lead hazards. Of the 2.7 million housing units with dust lead hazards but no intact or deteriorated lead-based paint, approximately 270,000 units had soil lead hazards, and occupants in another 700,000 units reported having a lead hobby or an occupation potentially using lead, all of which can contribute to interior dust lead levels.

Bare soil lead hazards. An estimated 5% (~4.9 million) of homing units nationwide had play area soil lead levels [greater than or equal to] 400 ppm, the current U.S. EPA/HUD standard (U.S. EPA 2001; U.S. HUD 1999) (Table 8). Among all housing unit yard areas, 7% (~6.3 million) have bare soil lead levels [greater than or equal to] 1,200 ppm, the current U.S. EPA/HUD standard outside of play areas (U.S. EPA 2001; U.S. HUD 1999) (Table 9). Soil lead levels are also related to deteriorated exterior lead-based paint. Comparing units with and without deteriorated exterior lead-based paint, the percentage of units with bare soil lead levels [greater than or equal to] 1,200 ppm decreases from 24% to only 4%, respectively (Table 10).

Lead-based paint. Our results indicate that 38 million units have lead-based paint somewhere in the interior or on the exterior of the unit (Table 4). The influences of age, demographic, and socioeconomic factors on the presence of lead-based paint are similar to those presented in Table 5 for significant lead-based paint hazards. Although 40% of housing units had lead-based paint somewhere, most surfaces, even in older housing stock, did not have lead-based paint (Table 11). In post-1960 housing, only 0-2% of interior surfaces had lead-based paint, whereas 0-12% of exterior surfaces had lead-based paint. Even in older pre-1940 housing, only 7-22% of interior surfaces and 24-41% of exterior surfaces had lead-based paint. In almost all age categories for both interior and exterior surfaces, the building components with the highest prevalence of lead-based paint were windows and doors. These are friction and impact surfaces that can generate significant levels of lead dust and paint chips.

For all housing units, we estimate 7.5 billion [ft.sup.2] of interior lead-based paint and 29.2 billion [ft.sup.2] on exterior surfaces, roughly 2% and 22% of the total interior and exterior painted surfaces, respectively. On average, for each housing unit with lead-based paint, there are 259 [ft.sup.2] of lead-based paint on interior surfaces and 996 [ft.sup.2] on exterior surfaces (Table 12).

A comparison of the 1990 HUD survey (U.S. EPA 1995; U.S. HUD 1990) with this study shows that the number of units with lead-based paint fell from 64 million units in 1990 to 38 million in 2000 (Tables 4 and 13). Some possible reasons for this decline are discussed below.

Discussion

The results show that despite considerable progress, significant lead-based paint hazards remain prevalent, existing in 25% of all U.S. housing. The association between lead-based paint, lead-contaminated dust, and lead-contaminated soil is consistent with the 1990 HUD survey. Yet 2.7 million homes without lead-based paint had dust lead hazards at the time of the recent survey. However, the fact that lead-based paint was not found in these homes at the time of the survey does not necessarily mean it had never been present at some time in the past. Ongoing housing rehabilitation, maintenance, and repainting all tend to remove lead-based painted surfaces but may leave behind dust lead hazards. Also, some lead-contaminated dust may be from lead-contaminated soil tracked into homes. Although some dust lead may be due to aerosol deposition from ambient air, air lead levels in the United States have declined greatly with the phaseout of leaded gasoline. It is also possible that lead-contaminated dust can originate from lead-based paint in nearby dwellings that are undergoing rehabilitation, maintenance, or repainting. Additionally, some of the lead hobbies or occupations reported by occupants could produce a lead dust hazard. In any case, Table 7 shows that the vast majority of houses with dust lead hazards have lead-based paint on either the interior or exterior, and that houses with deteriorated lead-based paint are far more likely to have dust lead hazards. Further research is needed to identify other potential sources of dust lead hazards.

The apparent decrease in the number of units with lead-based paint over the past decade was greater than expected, declining from about 64 million (or 83%) of pre-1980 housing units to 38 million (or 40%) of all 96 million housing units in the sampling frame of this study, a decline of 26 million units. A number of factors that likely contributed to this apparent decline are discussed below.

Ongoing lead hazard control activities. The number of units undergoing lead hazard control likely increased over the past decade because of HUD's lead hazard control grants to local governments; other similar local, state, and federal lead hazard control programs; lead hazard control requirements in HUD's public housing program and federally assisted housing programs; promulgation and enforcement of the U.S. EPA/HUD lead-based paint disclosure regulation (U.S. HUD and U.S. EPA 1996); and increased public awareness of lead-based paint hazards, which likely resulted in privately funded lead hazard control activities. The effect of public education (carried out largely through federal, state, and local programs) in prompting lead hazard control efforts is difficult to quantify but may be much larger than is currently understood.

Demolition and renovation. Although demolition, remodeling, and renovation activities are known to increase exposures in the short run if lead-safe work practices are not used, they reduce both the number of units and the number of surfaces within units with lead-based paint over the long run. Over the past 5 years, standardized curricula and training courses have been developed to educate the work force on lead-safe work practices, and the U.S. EPA has promulgated a final rule regarding public education prior to certain renovation practices (U.S. EPA 1998). This educational effort should reduce the generation of lead-contaminated dust during renovation and maintenance.

It is widely assumed that the phaseout of lead in gasoline and lead in food canning are primarily responsible for most of the decline in population blood lead levels over the past several decades (along with regulation of lead in water and industrial emissions). But it is likely that housing rehabilitation, maintenance, and demolition also had a significant impact over the same time period. The President's Task Force on Environmental Health Risks and Safety Risks to Children (2000) used data from the American Housing Survey and other sources to estimate the size of this effect during the 1990s. Those data show that older units with lead-based paint are more likely to undergo rehabilitation or demolition than are newer houses. From 1989 to 1999, the number of pre-1940 units declined by 2.8% annually, the number of 1940-1959 units declined by 2.65% annually, and those from 1960-1974 declined by 2.1% annually. In short, from 1989 to 1999, the number of units with lead-based paint declined by a total of about 10 million units due to housing demolition and renovation alone (Appendix to the President's Task Force Report 2000). This same pattern likely occurred during earlier decades as well, contributing to the overall decline in population blood lead levels in ways not previously recognized.

Improvements in laboratory and XRF technology and quality control This study used an XRF model that is both more precise and more accurate than the instrument used in 1990 (U.S. HUD 1990). Over the past decade, Performance Characteristics Sheets defining acceptable tolerance limits for all commercially available instruments have been published (U.S. HUD 1997), which has spurred the introduction of a new generation of more precise and accurate lead-based paint analyzers, one of which was used in this study. In addition, all states now have certification (licensing) laws (or are covered by the U.S. EPA) for lead-based paint inspectors (U.S. EPA 1996); in 1990, only one state had such a law. All of this makes it less likely to misclassify a surface with lead-based paint in the more recent survey.

Larger sample size. The recent study sampled more units (831 vs. 284), more rooms within units (4-6 rooms vs. 2 rooms), and completed more measurements within rooms, compared to the 1990 survey (U.S. HUD 1990), making these estimates more precise and accurate. The larger number of measurements would be expected to increase the number of homes with lead-based paint, contrary to the findings above, if the number of units with lead-based paint in fact had remained the same. There may be other methodologic differences in the two surveys that could explain some of the observed decline, which will be explored in future papers.

Other key findings. Differences in the definition of what constitutes a lead-based paint hazard and the protocols to measure lead in dust and soil changed greatly between the two surveys, making a direct comparison of hazard prevalence problematic. The percentage of housing units with deteriorated lead-based paint actually increased slightly, from 19% in 1990 to 22% in the present study (Table 13). Although the difference did not reach statistical significance, such an increase could reflect continued aging of the housing stock and changes in the definition of paint deterioration used in the two studies. If the prevalence of deteriorated paint either increased or remained constant over the past decade, additional efforts are needed to maintain lead-based paint in a way that ensures that it does not deteriorate and present new hazards.

This study shows that most painted surfaces, even in older housing, are not coated with lead-based paint. Use of lead-safe work practices on surfaces with lead-based paint is essential in order to minimize dust, paint chips, and contaminated soil that may be generated during maintenance and housing rehabilitation activities, because only a small amount of lead-based paint is needed to produce very high dust lead levels. For example, if sanded and turned into contaminated dust that is spread across an average-size room, only 1 [ft.sup.2] of paint at a lead concentration of 1 mg/[cm.sup.2] (the federal standard) is needed to produce a settled dust lead level of 9,300 [micro]g/[ft.sup.2], several orders of magnitude above current dust lead standards (U.S. HUD 1995).

This study also suggests that rental properties are somewhat more likely to have lead-based paint hazards than are owner-occupied properties (30% vs. 23%, respectively), perhaps because of the increased turnover rates and lower maintenance levels that may be more common in rental units. Thus, efforts to increase homeownership may also serve to reduce the prevalence of childhood lead poisoning.

Although it has been widely assumed that large cities have a higher prevalence of lead-based paint hazards than do smaller ones, these data show that urban and rural areas both have roughly the same prevalence--about 26% (Table 5). These results suggest that greater attention may need to be given to rural housing, although large cities clearly have more units with lead-based paint hazards within relatively small geographic areas.

The percentage of building components coated with lead-based paint in housing built after the 1978 ban is 0-3% (Table 11). This suggests that the ban was not immediately effective in removing stocks of lead-based paint from retail and wholesale outlets. It also suggests that there may be continuing use of industrial or marine lead-based paint, which is still available, in housing. The fact that about half of the XRF readings indicating a lead concentration greater than 1 mg/[cm.sup.2] were taken on tiled surfaces means that the percentage of surfaces with lead-based paint in newer housing is between 1% and 2%. It is not known whether lead was actually present in the tile itself or in the glazing of the tile, or whether it was an instrumentation artifact. Furthermore, it is not known whether tile poses a significant source of lead exposure to children. Further analyses of the prospect of continuing contamination of U.S. housing through new application of lead-based paint and the nature and importance of lead in tile are both needed. Nevertheless, it is clear that lead-based paint hazards in housing built after 1978 are very rare.

Conclusion

This study shows that despite a large decline in the number of housing units with lead-based paint from 1990 to 2000, there are still millions remaining with hazards. Resources should be directed to those most likely to cause childhood lead poisoning: older housing units with lead-based paint hazards that are occupied by (or likely to be occupied by) children under 6 years of age and are low-income and/or are undergoing certain housing rehabilitation or maintenance that disturbs surfaces coated with lead-based paint. Hazard controls should focus on deteriorated lead-based paint, windows, doors, dust, and bare soil in play areas. Window replacement also has other important benefits, such as energy conservation.

This study confirms a prediction released by the President's Task Force in February 2000. That forecast indicated that based on trends in demolition, housing rehabilitation, lead hazard control, and other factors, the number of units with lead-based paint hazards in 1999 could be expected to be 24 million. This study found that the actual number is 24 [+ or -] 2.7 million units, making the task force estimate well within the confidence interval of this survey. The task force report indicated that private and public expenditures for the incremental cost of lead hazard control totaling approximately $230 million per year for 10 years would be needed to virtually eliminate childhood lead-based paint poisoning and realize a net benefit of $890 million per year for 10 years from avoided childhood lead-poisoning cases. This cost analysis factors in ongoing housing rehabilitation, maintenance, and lead hazard control, as well as regulation of federally assisted low-income housing. Further efforts are needed to improve maintenance standards by incorporating lead-safe work practices into routine housing operations, especially in low-income housing.

Further efforts are also needed to educate maintenance and housing rehabilitation workers, property owners, parents, and others to help ensure that lead-based paint remaining in millions of houses does not become hazardous and pose future risks to millions of children born into or occupying such houses in the coming decades.

Table 1. Comparisons of the National Lead-Based Paint Survey
population with the American Housing Survey (AHS) and the Current
Population Survey (CPS).
                                                National Lead-Based
                                                   Paint Survey
                               No. estimated       estimates
Housing unit characteristic    (thousands)     Percent    95% Cl (b)
                                              estimated
                                                 (a)

Total housing units (d)           95,688        100
Construction year
  1978-1998                       29,774         31         30-32
  1960-1977                       27,874         29         28-30
  1940-1959                       20,564         21         20-23
  Before 1940                     17,476         18         17-20
Region
  Northeast                       19,290         20         19-22
  Midwest                         22,083         23         22-24
  South                           35,474         37         36-39
  West                            18,841         20         18-21
Urbanization
  MSA [greater than
  or equal to] 2
  million population              26,814         28         24-32
  MSA < 2 million
  population                      45,753         48         43-53
  Non-MSA                         23,121         24         19-30
One or more children under
age 18                            36,994         39         38-39
  Refusal/don't know (e)             290
Housing unit type
  Single family                   82,651         86         84-89
  Multifamily                     13,037         14         11-16
Tenure
  Owner occupied                  66,232         69         65-73
  Renter occupied                 29,074         30         27-34
  Refusal/don't know (e)             381
Household income ($30,000)
  < $30,000/year                  33,830         35         30-41
  [greater than or
   equal to] $30,000/year         56,111         59         54-63
  Refusal/don't know (e)           5,747
Household income ($20,000)
  $0-19,999/year                  19,359         20         17-24
  $20,000-39,999/year             25,855         27         23-31
  $40,000-59,999/year             19,316         20         16-25
  [greater than or
  equal to] $60,000/year          22,890         24         20-28
  Refusal/don't know (e)           8,268
Poverty
  In poverty                      13,221         14         11-16
  Not in poverty                  76,336         80         77-82
  Refusal/don't know (e)           6,130          6
Race
  White                           77,005         80         78-83
  African American                10,365         11          9-13
  Other (f)                        6,571          7           5-8
  Refusal/don't know (e)           1,746          2
Ethnicity
  Hispanic/Latino                  7,434          8           6-10
  Not Hispanic/Latino             87,008         91          88-93
  Refusal/don't know (e)           1,246          1

                                                            CPS (1998-
                                               AHS (1997)    99) (c)
Housing unit characteristic    Housing units     (%) (c)       (%)
                                 in sample

Total housing units (d)           831
Construction year
  1978-1998                       220             30
  1960-1977                       267             30
  1940-1959                       186             20
  Before 1940                     158             20
Region
  Northeast                       155             20
  Midwest                         196             24
  South                           277             35
  West                            203             21
Urbanization
  MSA [greater than
  or equal to] 2
  million population              276                              30
  MSA < 2 million
  population                      417                              47
  Non-MSA                         138                              23
One or more children under
age 18                            398
  Refusal/don't know (e)            3             37
Housing unit type
  Single family                   705             88
  Multifamily                     126             12
Tenure
  Owner occupied                  539                              67
  Renter occupied                 289                              33
  Refusal/don't know (e)            3
Household income ($30,000)
  < $30,000/year                  309                              40
  [greater than or
   equal to] $30,000/year         482                              60
  Refusal/don't know (e)           40
Household income ($20,000)
  $0-19,999/year                  189                              26
  $20,000-39,999/year             228                              27
  $40,000-59,999/year             152                              19
  [greater than or
  equal to] $60,000/year          203                              28
  Refusal/don't know (e)           59
Poverty
  In poverty                      137                              15
  Not in poverty                  651                              85
  Refusal/don't know (e)           43
Race
  White                           622             83
  African American                116             12
  Other (f)                        77              6
  Refusal/don't know (e)           16
Ethnicity
  Hispanic/Latino                  86              9
  Not Hispanic/Latino             736             91
  Refusal/don't know (e)            9

(a) All percentages are calculated with total housing units (95,688,000)
as the denominator; percentages may not total 100% due to rounding,
(b) Cl = 95% confidence interval for the estimated number or percentage,
(c) CPS data were taken from the 1998 CPS for household income and
poverty measures and from the 1999 CPS for urbanization and tenure
measures. (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.

Table 2. Location and type of sample collected.

Rooms and                 Yard/play
sample type                 areas     Walls   Ceilings   Windows   Doors

Kitchen
  Lead dust                                                 X
  Paint                                 X        X          X        X
Living room/family room
  Lead dust                                                 X
  Paint                                 X        X          X        X
Bedroom(s)
  Lead dust                                                 X
  Paint                                 X        X          X        X
Other random room(s)
  Lead dust                                                 X
  Paint                                 X        X          X        X
Major entrance
  Lead dust
Interior common area
(multifamily only)
  Lead dust
Exterior
  Paint                                 X                   X        X
  Soil                        X

Rooms and                 Other
sample type               trim    Floors

Kitchen
  Lead dust                         X
  Paint                    X        X
Living room/family room
  Lead dust                         X
  Paint                    X        X
Bedroom(s)
  Lead dust                         X
  Paint                    X        X
Other random room(s)
  Lead dust                         X
  Paint                    X        X
Major entrance
  Lead dust                         X
Interior common area
(multifamily only)
  Lead dust                         X
Exterior
  Paint                    X
  Soil

Table 3. Paint testing locations.

Interior paint testing per room   Exterior paint testing

Wall--all four major walls        Siding--all four walls
Ceiling                           Trim--two miscellaneous, one
Door and related trim               random wall
  (if present)                    Window and related trim--one
                                    random wall
Window and related-trim
  (if present)                    Door of major entrance to building
Baseboard                         Porch and railing
Floor                             Surfaces with deteriorated paint
Surfaces with deteriorated paint or friction areas

Table 4. Type of lead-based paint hazar

                                  No. housing             Percent
                                    units             housing units (a)
                                (thousands) (a)
Type of hazard                Estimate  95% Cl (a)    Estimate   95% Cl

Significantly deteriorated
  lead-based paint           13,634   10,928-16,341     14       11-17
Interior lead-contaminated
  dust                       15,468   12,982-17,954     16       14-19
Lead-contaminated soil        6,460     3,122-9,799      7        3-10
Any significant lead-based
  paint hazard               24,026   21,306-26,746     25       22-28
Any lead-based paint         37,897   34,521-41,272     40       36-43

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

Table 5. Prevalence of significant lead-based paint hazards
in housing units (number and percent) (a)

                                               No. housing
                                            units (thousands)
Characteristics                       All       Units     95% Cl (b)
                                    housing      with
                                    units (b)   hazards

Total occupied housing units         95,688     24,026    21,306-26,746
Region
  Northeast                          19,290      7,679     5,748-9,611
  Midwest                            22,083      7,250     6,402-8,097
  South                              35,474      6,191     4,964-7,419
  West                               18,841      2,906     1,856-3,956
Construction year
  1978-1998                          29,774      1,042       169-1,915
  1960-1977                          27,874      2,340     1,445-3,235
  1940-1959                          20,564      8,826     6,720-10,933
Before 1940                          17,476     11,818    10,045-13,591
One or more children <6 years old
  All housing units                  16,402      4,155     2,948-5,363
  Units built 1978-1998               5,847      <58 (d)       --
  Units built 1960-1977               5,098
  Units built 1940-1959               3,055      1,732     1,088-2,375
  Units built before 1940             2,401      1,955     1,190-2,720
Urbanization
  MSA [greater or equal to]
  2 million population               26,814      6,793     4,978-8,609
  MSA < 2 mill ion population        45,753     10,232     8,171-12,293
  Non-MSA                            23,121      7,001     3,848-10,153
Housing unit type
  Single family                      82,651     21,584    18,974-24,194
  Multifamily                        13,037      2,442     1,208-3,676
Occupant status
  Owner occupied                     62,232     15,305    13,191-17,419
  Renter occupied                    29,074      8,721     6,583-10,859
  Refusal/don't know (f)                381
Household income
  < $30,000/year                     33,830     12,007     9,336-14,679
  [greater than or equal to]
  $30,000/year                       56,111     10,464     8,250-12,678
  Refusal/don't know (f)              5,747
One or more children <6 years old
  All income categories              16,402      4,155     2,948-5,363
  <$30,000/year                       4,791      1,201       600-1,801
  [greater than or equal to]
  $30,000/year                       11,236      2,860     1,763-3,957
  Refusal/don't know (f)                375
Government support
  Government support                  4,809        805       275-1,335
  No government support              86,070     22,198    19,252-25,144
  Refusal/don't know (f)              4,809
Poverty
  In poverty                         13,221      4,976     3,458-6,494
  Not in poverty                     76,336     16,576    13,598-19,555
  Refusal/don't know (f)              6,130
Race
  White                              77,005     19,089    16,475-21,703
  African American                   10,365      2,969     1,807-4,131
  Other (g)                           6,571      1,496       672-2,321
  Refusal/don't know (f)              1,746
Ethnicity
  Hispanic/Latino                     7,434      2,399     1,235-3,564
  Not Hispanic/Latino                87,008     21,196    18,674-23,719
  Refusal/don't know (f)              1,246

                                          Percent
                                       housing units (c)    No. housing
Characteristics                     Units with   95% Cl      units in
                                     hazards                  sample


Total occupied housing units             25       22-28          831
Region
  Northeast                              40       30-50          155
  Midwest                                33       29-37          196
  South                                  17       14-21          277
  West                                   15       10-21          203
Construction year
  1978-1998                               3         1-6          220
  1960-1977                               8        6-12          267
  1940-1959                              43       32-51          186
Before 1940                              68       56-75          158
One or more children <6 years old
  All housing units                      25       18-33          184
  Units built 1978-1998                  <1 (d)      --           56
  Units built 1960-1977                   9        0-18           61
  Units built 1940-1959                  57       36-78           40
  Units built before 1940                81      50-113 (e)       27
Urbanization
  MSA [greater or equal to]
  2 million population                  25        19-32          276
  MSA < 2 mill ion population           22        18-27          417
  Non-MSA                               30        17-44          138
Housing unit type
  Single family                         26        23-29          705
  Multifamily                           19         9-28          126
Occupant status
  Owner occupied                        23        20-26          539
  Renter occupied                       30        23-37          289
  Refusal/don't know (f)                                           3
Household income
  < $30,000/year                        35        28-43          309
  [greater than or equal to]
  $30,000/year                          19        15-23          482
  Refusal/don't know (f)                             40
One or more children <6 years old
  All income categories                 25        18-33          184
  <$30,000/year                         25        13-38           61
  [greater than or equal to]
  $30,000/year                          25        16-35          117
  Refusal/don't know (f)                                           6
Government support
  Government support                    17         6-28           54
  No government support                 26        22-29          733
  Refusal/don't know (f)                                          44
Poverty
  In poverty                            38        26-49          137
  Not in poverty                        22        18-26          651
  Refusal/don't know (f)                                          43
Race
  White                                 25        21-28          622
  African American                      29        17-40          116
  Other (g)                             23        10-35           77
  Refusal/don't know (f)                                          16
Ethnicity
  Hispanic/Latino                       32        17-48           86
  Not Hispanic/Latino                   24        21-27          736
  Refusal/don't know (f)                                           9

(a) Significant lead-based paint hazard means a lead-based paint hazard
above de minimis levels as defined in U.S. EPA and U.S. HUD regulations
(U.S. EPA 2001; U.S. HUD 1999). The de minimis levels for paint
deterioration are [less than or equal to]20 [ft.sup.]2 (exterior) or
[less than or equal to] 20 [ft.sup.2] (interior) of lead-based paint
on large surface area components (walls, doors), or damage to [less
than or equal to] 10% of the total surface area of interior small
surface area component types (windowsills, baseboards, trim), ball
percentages are calculated with total housing units (95,688,000) as
the denominator; percentages may not total 100% due to rounding;
Cl = 95% confidence interval for the estimated number or percentage.
(c) All percentages are calculated with the "All housing units" column
in each row used as the denominator. (d) No 1978-1998 housing units
with one or more children < 6 years old in this sample have lead-based
paint hazards. (e) Upper 95%Cl value > 100% reflects uncertainty in
number of housing units in first data column. (f) Refusals and "don't
know" responses by survey respondents, (g)"Other" race includes Asian,
American Indian or Alaskan Native, Native Hawaiian or other Pacific
Islander, and more than one race.

Table 6. Dust lead loadings on floors and windows.

Statistic           Floors ([micro]g/   Windowsills   Window troughs
                       [ft.sup.2])      ([micro]g/      ([micro]g/
                                        [ft.sup.2])     [ft.sup.2])

Arithmetic mean           13.6             194.9          1,990.9
Arithmetic SD            483.5           1,682.7         12,086.5
Geometric mean             1.1               9.4             96.4
Geometric SDa              3.8               9.3             14.4
25th percentile          0.375               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
HUD/EPA standards           40               250               NA
No. samples              3,894             2,302          1,607

NA, not applicable. For this table, zero and negative values were set
to 0.375.
(a) The geometric standard deviation is computed as exp(s), where s is
the arithmetic standard deviation of the natural Iogarithms of the
loadings (e.g., Gilbert 1987).

Table 7. Association between dust lead hazards and presence and
condition of interior lead-based paint (all housing unit ages,
thousands of units).

                                  No lead-based
                                paint on interior      No interior
                                   or exterior      lead-based paint (a)
Characteristic                    No.   Percent       No.    Percent

No interior dust lead hazard
  Estimate (b)                  55,105    95        62,752     94
  Lower 95% Cl (c)              51,893    90        60,141     90
  Upper 95% Cl                  58,318   100        65,363     98
Interior dust lead hazards
  Estimate (b)                   2,686     5         4,068      6
  Lower 95% Cl                   1,372     2         2,584      4
  Upper 95% Cl                   4,001     7         5,552      8
Total housing units             57,791   100        66,820    100

                                  Interior         Significantly
                                  lead-based        deteriorated
                                paint in good        interior
                                  condition       lead-based paint
Characteristic                    No.    Percent     No. Percent

No interior dust lead hazard
  Estimate (b)                  15,244      67      2,389   39
  Lower 95% Cl (c)              12,633      56      1,565   26
  Upper 95% Cl                  17,855      78      3,213   53
Interior dust lead hazards
  Estimate (b)                   7,508      33      3,727   61
  Lower 95% Cl                   6,024      26      2,505   41
  Upper 95% Cl                   8,992      40      4,949   81
Total housing units             22,752     100      6,116  100

(a) Includes houses with only exterior lead-based paint, (b) Estimate is
either the number of permanently occupied, noninstitutional housing
units in which children are permitted to live, or the percentage of
total housing units, (c) Cl, 95% confidence interval for the estimated
number or percentage.

Table 8. Distribution of bare soil lead concentrations in children's
play areas.
                           No. housing  units        Percent housing
Bare play area              (thousands) (a)             units (b)
soil lead levels (ppm)    Estimate   95% Cl (a)      Estimate   95% Cl

[greater than or
  equal to] 0              76,404    69,826-82,982      80      73-87
[greater than or
  equal to] 20             49,019    42,946-55,092      51      45-58
[greater than or
  equal to] 50             28,878    25,828-31,929      30      27-33
[greater than or
  equal to] 200            10,849     7,899-13,800      11       8-14
[greater than or
  equal to] 400 (c)         4,856     2,096-7,616        5       2-8
[greater than or
  equal to] 1,200           2,493       458-4,529        3       1-5
[greater than or
  equal to] 1,600           2,078        92-4,063        2       0-4
[greater than or
  equal to]> 2,000          1,777         0-3,871        2       0-4
[greater than or
  equal to] 5,000             380         0-1,231        0       0-1
No play area               12,368     6,659-18,077      13       7-19
Missing (d)                 6,916     1,862-11,969       7       2-13
Total                      95,688                      100

Bare play area             Housing
soil lead levels (ppm)    units (n)

[greater than or
  equal to] 0               294
[greater than or
  equal to] 20              209
[greater than or
  equal to] 50              127
[greater than or
  equal to] 200             101
[greater than or
  equal to] 400 (c)          84
[greater than or
  equal to] 1,200            82
[greater than or
  equal to] 1,600            80
[greater than or
  equal to]> 2,000           77
[greater than or
  equal to] 5,000             1
No play area                 53
Missing (d)                  23
Total                       375

(a) All percentages are calculated with total housing units
(95,688,000) as the denominator; percentages may not total 100% due to
rounding. (b) All percentages are calculated with total housing units
(95,688,000) as the denominator. (c) U.S. EPA standard for play areas.
(d) Missing means that soil was present but no lead value is available
(usually due to inaccessibility or respondent refusal).

Table 10. Association between bare soil lead concentration and housing
units with or without deteriorated exterior lead-based paint.
                                           Without significantly
                       Without any lead-   deteriorated exterior
Bare soil lead           based paint       lead-based paint (a,b)
concentration (ppm)    Percent   95% Cl    Percent   95% Cl (a)
[greater than
  or equal to] 0         83      78-88       83         77-88
[greater than
  or equal to] 20        49      41-56       56         48-63
[greater than
  or equal to] 50        28      20-36       38         30-47
[greater than
  or equal to] 200        5       1-9        13          9-17
[greater than
  or equal to] 400        3       0-5         8          5-11
[greater than
  or equal to] 1,200      1       0-3         4          2-7
[greater than
  or equal to] 1,600      1       0-3         2          1-4
[greater than
  or equal to] 2,000      1       0-2         2          0-4
[greater than
  or equal to] 5,000      0       0-0         1          0-2
Missing (c)               0       0-0        30          0-0
No bare soil             14      10-19       15         11-20
No soil (d)               3       0-6         2          0-4
Total                   100                 100

                       With significantly
                       deteriorated exterior
Bare soil lead         lead-based paint (a,b)
concentration (ppm)    Percent   95% Cl
[greater than
  or equal to] 0         73      55-92
[greater than
  or equal to] 20        73      54-92
[greater than
  or equal to] 50        67      51-83
[greater than
  or equal to] 200       39      19-58
[greater than
  or equal to] 400       30      11-49
[greater than
  or equal to] 1,200     24       7-41
[greater than
  or equal to] 1,600     17       4-30
[greater than
  or equal to] 2,000     13       2-24
[greater than
  or equal to] 5,000      8       0-17
Missing (c)               1       0-5
No bare soil             22       3-41
No soil (d)               4       0-9
Total                   100

(a) All percentages are calculated with total housing units (95,688)
as the denominator; percentages may not total 100% due to rounding.
(b) Percentages are calculated with the number of housing units without
any lead-based paint, and with and without deteriorated lead-based
paint, 57,791,000, 11,473,000 and 84,215,000, respectively, as the
denominators. (c) "Missing" means that soil was present but no lead
value is available (usually due to inaccessibility or respondent
refusal). (d) "No soil" means that there was no soil on the property
to sample.

Table 11. Building components coated with lead-based paint by year of
construction (%).
                    All    1978-   1960-   1940-   Before
Component type     years   1998    1977    1959     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
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

Table 12. Surface area of lead-based paint.
                     National total surface area
                         of lead-based paint
                                                   Avg surface area
                     Square feet    Paint on       per housing unit
Component             (billions)   component (%)     ([ft.sup.2])
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

Avg, average.

Table 13. Comparison of the prevalence of lead-based paint (a) to that
in the 1990 HUD survey (housing units built before 1980).
                                              1990 HUD national
Location and condition    1990 HUD survey        survey (c)
of lead-based paint       No. (c)   Percent   No. (c)   Percent

Housing units built
  before 1980             77,177      100     68,756      100
Units with lead-
  based paint             64,059       83     34,195       50
Interior lead-based
  paint                   48,986       63     26,184       38
Exterior lead-based
 paint                    56,495       73     27,373       40
Units with deteriorated
  lead-based paint (a)    14,354       19     14,962       22
Interior deteriorated
  lead-based paint         5,596        7      7,281       11
Exterior deteriorated
  lead-based paint         9,657       13     11,784       17

(a) "Deteriorated lead-based paint is as defined in U.S. HUD (1995).
(b) All the data in this table are restricted to housing built
before 1980. (c) Thousands of housing units.

We thank the members of the hundreds of households who participated in this study and generously provided their time and access to their homes. We also thank the field interviewers and lead-based paint inspectors who collected the data and environmental samples.

This work was funded by the U.S. Department of Housing and Urban Development (HUD Contract C-OPC-21356) and the National Institute of Environmental Health Sciences (NIEHS). The survey plan was reviewed and approved by the institutional review boards of Westat and of the NIEHS.

Address correspondence to D.E. Jacobs, Office of Healthy Homes and Lead Hazard Control, U.S. Department of Housing and Urban Development, P-3202, 451 Seventh St. SW, Washington, DC 20410 USA. Telephone: [phone]. Fax: [phone]. E-mail: [e-mail]

Received 28 August 2001; accepted 5 March 2002.

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--. 2001. National Survey of Lead and Allergens in Housing. Final Draft Report, Vol II: Design and Methodology, Rev 6.0. Washington, DC:U.S. Department of Housing and Urban Development. Available: www.hud.gov/offices/lead [accessed 16 August 2002].

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Vojta PJ, Friedman W, Marker D, Clickner RP, Rogers JW, Viet SM, et al. 2002. First national survey of lead and allergens in housing: survey design and methods for the allergen and endotoxin components. Environ Health Perspect 110:527-532.

David E. Jacobs, (1) Robert P. Clickner, (2) Joey Y. Zhou, (1) Susan M. Viet, (2) David A. Marker, (2) John W. Rogers, (2) Darryl C. Zeldin, (3) Pamela Broene, (2) and Warren Friedman (1)

(1) U.S. Department of Housing and Urban Development, Office of Healthy Homes and Lead Hazard Control, Washington, DC, USA; (2) Westat, Rockville, Maryland, USA; (3) Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA