When Mary Jean Brown and her colleagues at Harvard T.H. Chan School of Public Health analyzed five decades of national blood lead data, they found a public health triumph: children's lead exposure in the United States has declined sharply since the 1970s, thanks to federal policies that removed lead from gasoline and paint. Yet the national numbers mask a persistent and troubling reality that local data from seven states—Connecticut, Delaware, Illinois, Indiana, Massachusetts, Pennsylvania and South Dakota—makes undeniable: children of color and children from low-wealth families continue to face significantly higher lead exposures than their peers.
The problem matters urgently because no level of lead in children's blood is safe. Lead damages the developing brain, jeopardizing academic prospects and contributing to problems with learning, attention and behavior. The disparities, researchers found, stem largely from older, poorly maintained housing where lead paint remains a hazard, passed down across generations to the families least able to afford remediation.
Brown, former chief of lead poisoning prevention at the Centers for Disease Control and Prevention, put it plainly: "Lowering blood lead levels in children nationwide is one of public health's great success stories, but the national data don't tell the whole story. At the local level, too many children still face higher exposures." Her team's analysis, published in the American Journal of Public Health and conducted alongside scientists and health advocates from Project TENDR, reveals the critical gap between aggregate national progress and the reality for vulnerable communities.
The research identified not only old sources of harm but new ones: lead lurking in imported spices, traditional cosmetics, cultural cookware and folk medicines. These sources, researchers noted, disproportionately affect communities of color, further widening disparities in lead exposure across the country.
Aimin Chen, a co-author and professor at the University of Pennsylvania Medical School, emphasized the policy stakes: "Old and new sources of lead continue to put children of color and children from low-wealth families at greater risk of lead exposure that jeopardizes their academic prospects. Health care providers and policymakers need to understand that lead is still a serious issue for some children."
The research arrives at a precarious moment for public health surveillance. In October 2025, the Trump administration shut down the National Health and Nutrition Examination Survey (NHANES), the landmark health-monitoring program that has tracked Americans' health and chemical exposures since 1971. That decision means the most recent comprehensive national data—collected from 2021 to 2023—did not capture enough children to fully document disparities in elevated blood lead levels, leaving gaps precisely when understanding is most urgent.
Mark Mitchell, co-author and health director for the city of Hartford, Connecticut, called for restoration: "NHANES needs to be restored and expanded. We need more states to collect data by sociodemographic categories so we get a more accurate understanding of lead risks in our communities and more effectively address the needs of the highest-risk populations."
The authors recommend that governments at every level eliminate all remaining sources of lead, expand blood lead screening especially among minority and high-risk groups, and commit to analyzing and sharing data promptly so interventions can be swift and targeted. The national story of declining lead is real and worth celebrating. But closing the eyes to who still suffers most—and dismantling the tools to track progress—would be a step backward.