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Executive Summary of EPA 747-R-99-002
for the report
Lead Exposure Associate with
Renovation and Remodeling Activities: Phase III,
Wisconsin Childhood Blood-Lead Study,
March 1999 (EPA 747-R-99-002)
Lead poisoning is considered a serious threat to health in the United States. Since the use of lead in gasoline has been phased out, exposure to lead is now primarily from lead-based paint, particularly for children and construction workers. Federal programs undertaken to mitigate exposure to lead-based paint have focused on deteriorated paint and methods of abatement. As a result, the potential for exposure of workers and building occupants to lead resulting from renovation and remodeling (R&R) conducted with no abatement intent has not been evaluated.
To address this potential, the United States Congress directed the U.S. Environmental Protection Agency (EPA) to
. Determine the extent to which persons engaged in various types of residential R&R activities are exposed to lead
. 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.
To meet these objectives, the EPA launched a series of studies in 1993 collectively known as the R&R study. The first of these studies was the Environmental Field Sampling Study (EFSS or Phase I). In this study, lead levels in settled dust and in breathing zone air resulting from a variety of R&R activities (window replacement, sanding, paint preparation, demolition, cutting painted wood, etc.) were measured. These lead measurements were assumed to indicate the potential for lead exposure to construction workers and to building occupants as a result of R&R activities.
The second study, the Worker Characterization and Blood-Lead Study (WCBS or Phase II), examined the relationship between the blood-lead concentrations of construction workers and their R&R activities, work habits, medical histories, hobbies, etc.
In general, the results of Phases I and II indicated that, for some R&R activities, airborne lead levels within workers' breathing zones often exceeded the Occupational Safety and Health Administration's permissible exposure limit, but the blood-lead concentrations of workers that regularly engage in these activities were not likely to be elevated (?10 µg/dL). The implications for building occupants (especially children), however, were not as clear. The potential for exposure to occupants was characterized in the EFSS (Phase I) by measuring lead levels in dust that was generated by various R&R activities. The results of Phase I indicated that most R&R activities have a potential to disturb substantial amounts of lead and that occupants could be exposed to lead if appropriate containment and cleanup precautions are not employed. However, much uncertainty remained concerning the extent to which this potential for lead exposure translated to an actual internal dose for occupants (especially children).
Because children represent the population that is most likely to be sensitive to lead exposure from R&R activities, it became imperative that the EPA acquire additional data to assess the impact of residential R&R on children. Therefore, a third study, the Wisconsin Childhood Blood-Lead Study was conducted to determine the impact of residential R&R on the blood-lead concentrations of children occupying the residences.
The Wisconsin Childhood Blood-Lead Study (Phase III) was a retrospective case-control study designed to systematically examine the association between R&R activities and elevated blood-lead (EBL) levels (?10 ?g/dL) among children. The primary objective of the study was to compare the incidence of R&R activities in the residences of children with EBLs to R&R activities in the residences of children without EBLs. Another objective of the study was to determine if specific R&R activities were more prevalent in households with an EBL child than in households with a non-EBL child. The study targeted children under the age of six who were included in the Wisconsin Bureau of Public Health's blood-lead registry. These children resided in communities other than Milwaukee and Racine and were screened between March 1996 and December 1996.
To meet these objectives, telephone interviews were conducted with the parents or guardians of 3,654 children under the age of six about R&R activities in their residences. Responses during the telephone interview, as well as the child's blood-lead concentration as recorded in the Wisconsin Bureau of Public Health's blood-lead registry, were used to assess whether R&R, in general, increases a child's risk of having an elevated blood-lead concentration. The telephone questionnaire and blood-lead information were also used to determine if specific R&R activities were associated with an increased risk of an elevated blood-lead concentration.
The questionnaire was designed to determine whether R&R activities such as inside painting, outside painting, carpet and floor repair or replacement, and other repairs (such as window repair) were conducted in the residences of the children in the study. Although it is difficult to generalize the information beyond the study population, the frequency of general and specific R&R activities in residences populated by young children is a valuable product of this study. While the main objective of this study was to investigate the relationship between incidences of R&R activities and EBL children, a dose-response type relationship, this information is most useful when the degree of exposure is also known. In this case, if a slight increase in risk due to childhood lead exposure as a result of R&R activity is detected, the implications are best considered in light of the numbers of children likely to be exposed.
Analysis of the exposure data related to these activities revealed that at least one R&R activity had been conducted in 67.2 percent of the residences in the previous 12 months. Inside painting occurred in 50 percent of residences and outside painting, carpet and floor repair or replacement, or other repairs occurred in 20 percent. Some form of surface preparation was involved in 42.3 percent of R&R activities. Approximately 65 percent of the outside painting involved surface preparation, compared to 15 percent to 30 percent for each of the other types of activities. Most surface preparation involved hand scraping or sanding. Heat guns were used 7 percent of the time, and chemical paint removers were used 13.6 percent of the time. Surface preparation for painting was usually performed by the owner of the residence, the building superintendent, or apartment staff, while preparation for carpet and floor repair or replacement or other repairs was usually performed by paid professional contractors.
Univariate and multivariate logistic regression models developed from the questionnaire and blood-lead data collected for this study were used to
1. Determine if the incidence of R&R in residences was associated with an increased risk of an EBL (?10 ?g/dL).
2. Determine if specific R&R activities were associated with an increased risk of a child having an EBL.
The study demonstrated that residential R&R is associated with an increased risk of an EBL in children. The study also demonstrated that specific R&R activities are associated with an increase in the risk of an EBL in children. In particular, painting inside or outside, removing paint (using open flame torch, using heat guns, using chemical paint removers, and wet scraping\sanding), preparing surfaces by sanding or scraping, and living in a home when R&R work was done significantly increased the risk of EBLs. An EBL was more likely when a relative or friend not living in the household did the R&R work. In addition, the more rooms involved in the total R&R project, the more likely a child was to have an EBL. Any type of R&R work in the kitchen increased the odds of an EBL.
Overall, these results agree with those from earlier phases of the R&R Study - R&R activities that disturb lead-based paint increase the risk of exposure to occupants. For example, children living in a residence while R&R was conducted were 1.3 times more likely to have EBLs than children who did not live in a residence while R&R was conducted.
Further, the study has identified specific R&R activities and other conditions (such as age and type of residence) that are associated with increased risk to children as a result of lead exposure. This information can be used to develop regulations that focus on particular R&R activities (e.g., using a heat gun to remove paint), groups of persons (e.g., a household member other than the head of household or spouse) who perform the activities, and the other conditions (e.g., adult exposure, age of child) that significantly increase the risk to children. The results of this study concerning activities associated with increased risk (e.g., using a heat gun to remove paint) also can be combined with the worker profile results from Phase II to perform an overall assessment of the worker groups or situations where interventions are needed to reduce exposure from R&R.