Lead-contaminated soil tracked indoors can create hazardous levels of lead dust even in homes with no lead-based paint, according to a new study by Rutgers Environmental, Occupational and Health Sciences Institute researchers and community scientists in Trenton, New Jersey. The findings challenge a long-standing assumption that indoor lead exposure is primarily an old-house problem caused by deteriorating paint. Instead, the research shows that contaminated outdoor soil can become a significant indoor source of exposure, potentially putting children and families at risk regardless of when their homes were built.
The study focused on East Trenton, a neighborhood in the city’s North Ward that was added to the U.S. Environmental Protection Agency’s Superfund National Priorities List in 2025. Investigators linked the area’s soil contamination to lead released by 19th-century pottery manufacturing plants. Although those factories have been gone for generations, lead can persist in soil for decades because it does not break down naturally. Once present at the surface, it can be transferred to shoes, clothing, pets and household objects, allowing contaminated particles to move from yards and sidewalks into living spaces.
Researchers analyzed 242 samples of bare surface soil collected from 122 homes. The results were striking: 86 percent of the samples contained lead concentrations above the EPA’s residential soil hazard level of 200 parts per million. Nearly 94 percent exceeded screening levels associated with multiple possible exposure pathways. Surface soil is particularly important from a public-health perspective because it is the layer most accessible to children playing outdoors and the material most likely to become airborne or adhere to shoes before being carried inside.
“ This is especially concerning because all samples were collected from bare soil at the surface, which is the most likely to be accessed by children or tracked into homes,” said Sean Stratton, the study’s lead author and a recent Rutgers School of Public Health doctoral graduate. Children face heightened risks from lead because they frequently touch floors and dusty surfaces and may place their hands or objects in their mouths. Even relatively small amounts of lead can be harmful, particularly during early childhood, when the brain and nervous system are undergoing rapid development.
To determine whether outdoor contamination was entering homes, the team collected dust samples from floors, windowsills and window wells in 42 residences. Researchers also used X-ray fluorescence analyzers to assess lead-based paint levels in the homes. X-ray fluorescence is a non-destructive technique that identifies elements by measuring the characteristic radiation emitted when materials are exposed to X-rays. This allowed investigators to compare indoor dust contamination with the presence or absence of lead paint without removing large sections of painted surfaces.
In homes where researchers found no interior lead-based paint, 80 percent of floor-dust samples exceeded the applicable safety threshold. Crucially, the study found no significant difference in floor lead levels between homes with lead-based paint and those without it. That pattern supports the conclusion that contaminated soil was contributing to indoor lead dust independently of paint deterioration. The results also indicate that a home constructed after 1978—the year the federal government banned consumer uses of lead-based paint—cannot automatically be considered free of lead exposure risks.
“The thought was if there was lead in the dust, it’s coming from the paint on the walls and if a house was built after 1978 there was nothing to worry about, but that’s not always true,” said Brian Buckley, director of research with the Rutgers institute and a study author. The distinction matters because lead dust can be difficult to see and may accumulate in places that are routinely overlooked, including floor edges, window wells and entryways. Repeated tracking can gradually increase indoor concentrations, especially in homes without effective doormats, shoe-removal practices or frequent wet cleaning.
Lead exposure is associated with impaired brain development, learning difficulties, behavioral changes and damage to vital organs. There is no known safe level of lead exposure for children, and exposure can occur through inhalation or ingestion of contaminated dust and soil. The Rutgers researchers emphasize that their work was an observational study, meaning it measured contamination patterns rather than experimentally proving how every particle moved from a specific yard into a specific room. However, the combination of heavily contaminated surface soil, elevated indoor dust and similar floor-lead levels in homes with and without lead paint provides strong evidence that soil tracking is an important pathway.
The project was built around a partnership with the East Trenton Collaborative, a community organizing and development initiative. Residents were recruited and trained to collect soil samples, making local people active participants in the scientific process rather than simply subjects of an outside investigation. Shereyl Snider, the organization’s community organizer, was a co-author. The researchers said that earlier work with the Newark Water Coalition, in which community scientists distributed 500 water-testing kits, helped establish trust and demonstrated the value of resident-led environmental monitoring.
The findings arrive as communities across the United States continue to confront contamination left by historic industry, transportation and manufacturing. They suggest that lead-safety assessments should look beyond paint and include yards, entry points and indoor dust, particularly in neighborhoods with industrial histories. Rutgers researchers Adrienne Ettinger and Zorimar Rivera-Núñez also contributed to the study. Published in the Journal of Exposure Science & Environmental Epidemiology, the research underscores a simple but consequential message: a home may have no lead paint and still contain dangerous lead dust if contaminated soil is allowed to cross the threshold.
Subject of Research: Not applicable
Article Title: Lead soil contribution to dust loading in urban homes built before and after 1978, measured through a community academic partnership
Web References: Rutgers Environmental, Occupational and Health Sciences Institute: https://eohsi.rutgers.edu/ ; Rutgers School of Public Health: https://sph.rutgers.edu/ ; U.S. Environmental Protection Agency lead information: https://www.epa.gov/lead/learn-about-lead ; East Trenton Superfund site: https://cumulis.epa.gov/supercpad/SiteProfiles/index.cfm?fuseaction=second.cleanup&id=0203535
References: Journal of Exposure Science & Environmental Epidemiology, DOI: 10.1038/s41370-026-00949-5
Keywords: lead contamination, lead dust, soil pollution, indoor air quality, environmental health, children’s health, community science, Trenton, Superfund, lead-based paint, environmental exposure, public health
