Lead-contaminated soil tracked into homes can create hazardous levels of lead dust, even in residences without lead-based paint, according to researchers at the Rutgers Environmental, Occupational and Health Sciences Institute. The study, conducted with community scientists, suggests outdoor soil may be an overlooked source of indoor lead exposure.

Published in the Journal of Exposure Science & Environmental Epidemiology, the study focused on East Trenton, New Jersey. The U.S. Environmental Protection Agency added the neighbourhood to the Superfund National Priorities List in 2025 after identifying soil contaminated with lead associated with 19th-century pottery manufacturing.

Researchers found that 86% of 242 bare surface soil samples exceeded the EPA’s residential soil lead hazard level of 200 parts per million. In comparison, nearly 94% exceeded screening levels used when people may be exposed to lead from multiple sources. Lead author Sean Stratton said the findings were particularly concerning because surface soil can be easily accessed by children or tracked indoors.

The researchers also found elevated lead in household dust. Among homes without interior lead-based paint, 80% of floor dust samples exceeded the safety threshold. Interior floor lead levels did not differ significantly between homes with lead-based paint and those without it, suggesting that contaminated outdoor soil being carried indoors was a likely source.

Lead exposure is particularly dangerous for young children. According to the EPA, lead poisoning can affect brain development, damage vital organs and cause lasting behavioural and neurological problems. The findings highlight the importance of considering environmental sources of lead beyond deteriorating paint inside older homes.

Working with the East Trenton Collaborative, Rutgers researchers recruited and trained residents to collect soil samples from 122 homes. Researchers then used X-ray fluorescence analysers to identify lead-based paint and collected dust samples from floors, windowsills and window wells in 42 homes. The community-based approach provided researchers with access to residences while involving residents directly in investigating environmental risks in their neighbourhood.

Indoor lead exposure in the United States has historically been associated with deteriorating lead-based paint, which was commonly used in homes before the federal government banned consumer uses of lead paint in 1978. But the researchers said their findings challenge the assumption that newer homes, or homes without lead-based paint, are necessarily protected from indoor lead dust. Contaminated soil outside a residence can provide another pathway for exposure.

The East Trenton research builds on an earlier Rutgers partnership with the Newark Water Coalition, in which community scientists distributed 500 water-testing kits to investigate whether flushing taps could reduce lead exposure. That project found that flushing did not eliminate the risk. Researchers said the experience demonstrated the value of community-led data collection and helped establish trust for the East Trenton study, showing how residents can play an important role in identifying environmental health threats in their own communities.

More information: Sean Stratton et al, Lead soil contribution to dust loading in urban homes built before and after 1978, measured through a community academic partnership, Journal of Exposure Science & Environmental Epidemiology. DOI: 10.1038/s41370-026-00949-5

Journal information: Journal of Exposure Science & Environmental Epidemiology Provided by Rutgers University