Why do homeowners need to worry about lead contamination of their homes 30 years after lead-based paint was banned in the U.S.? In spite of decades of efforts to reduce exposure to lead, a significant number of houses in every city built before 1978 remain contaminated with lead. Weathering, chipping, scraping and sanding houses containing lead-based paint contaminates the surrounding soil. Exterior and interior lead-based paint contributes to lead-contaminated house dust. Since lead adsorbs strongly to soil particles, it can persist in soil for long periods. Children under six are at risk of developing a host of health impairments including intellectual deficits, diminished academic abilities, attention deficits, and behavioral problems.
In 1991, Centers for Disease Control (CDC) determined 10 micrograms per deciliter (μg/dL) to be the blood lead level (BLL) that should prompt public health action. Research conducted since 1991 strengthened the evidence that children’s physical and mental development can be affected at a BLL much lower than 10 μg /dL. In 2005, the American Academy of Pediatrics first recognized that BLLs below 10 μg/dL may impair cognitive functions in growing children, and no threshold for the toxic effects of lead could be identified. Since then, studies have consistently shown that lead can cause cognitive deficits and behavioral problems at BLLs below 5 μg/dL. In 2012, the Advisory Committee on Childhood Lead Poisoning Prevention of the CDC recognized that there is no safe level of lead exposure and adopted the use of a reference BLL of ≥ 5 μg/dL to trigger public health interventions.
The Flint water crisis, which made national headlines in 2015, raised public awareness of the problem of lead contamination of drinking water by lead pipes. However, soil lead contamination in older homes is believed to be an even larger public health hazard. Despite a continuous decline in BLL in children nationwide since the 1970s, a recent investigation by Reuters revealed that a number of neighborhoods all over the country do not reflect this improvement. Reuters reported that while most states report data on the percentage of children with elevated BLLs, this data is not broken down to the neighborhood level, to specifically identify the communities that are in need of intervention. Hence, Reuters conducted a detailed analysis, using BLL data at the neighborhood level, in census tracts or zip code areas from all 50 states. While census tracts are small county subdivisions with an average of 4,000 residents, zip codes have average populations of 7,500. Reuters identified 2,606 census tracts, and another 278 zip code areas with BLLs at least twice as high as those of Flint, where 5 percent of the children tested had high BLLs. This is twice the number of children nationwide with elevated BLLs. According to CDC data, only 2.5 percent of the children in U.S. tested BLLs higher than 5 μg/dL.
Why do we find a disproportionately large number of children poisoned with lead in certain neighborhoods? According to Reuters, these areas tend to be low-income neighborhoods, with a large number of older homes with crumbling paint and corroding lead pipes. Some of these neighborhoods are also contaminated by industrial pollution. Compounding the problem is a severe shortfall in testing for lead in children. In the 1990s, CDC recommended all U.S. children to be tested for lead. Now, CDC only requires testing “at risk” children. Citing the lack of funding, most state health agencies have been reducing the number of children tested. Currently, blood lead tests are required for all children in only 11 states and Washington, DC. Many states fall short on testing even “at risk” children. In addition to the severe shortfall in testing, there is also a lack of funding for lead abatement in older homes. Lead abatement involves a large expense, which most low-income families cannot afford. The estimated expense for lead abetment of an average home is between $10,000 and $30,000. Funding available through HUD is limited; many state health departments have also slashed funding for lead abatement. In addition, many buyers are not aware of the presence of lead when they buy or lease a home. Although homeowners are required to fill out a form to disclose any known information on lead-based paint before the sale or lease of a house built before 1978, they regularly circumvent this requirement by simply choosing not to test their homes for the presence of lead.