Lead levels are still too high inside and outside the Exide cleanup zone, study finds

New research is backing up what many residents in the Vernon area have already feared: the Exide cleanup is missing a lot of lead.

UC Irvine researchers found excessive lead in the area 11 years after the battery plant closed, as well as evidence that the remediation area may need to be expanded.

Lead is a toxic metal that can cause short- and long-term health effects, including neurological and reproductive changes. Exposure is especially dangerous for children and pregnant people.

A brief history of the Exide cleanup

Exide Technologies operated the 15-acre smelting facility in Vernon between 1922 and 2015. It processed 11 million auto batteries a year, releasing an estimated 3,500 tons of lead into the surrounding communities of Maywood, East Los Angeles, Commerce, Bell and Huntington Park.

After the federal government shuttered the plant over hazardous waste violations, California declared it an environmental disaster. It has since spent more than $750 million so far cleaning up the site and residential homes. The remediation zone was set at a 1.7-mile radius around the facility.

As of March 27, over 6,000 properties have been cleaned, according to the state’s Department of Toxic Substances Control, which oversees the effort.

Residents have complained for years about issues with the process and its thoroughness. Even though homes were deemed clean, investigations have found excessive lead on the grounds. Contractors have also reportedly violated state standards for soil removal and environmental regulations with toxic dust spread.

Key findings

Jill Johnston, an associate professor of environmental and occupational health at UC Irvine and lead author, said this is the  first peer-reviewed study looking at the problem and how it extends beyond the remediation zone.

Between October 2021 and September 2024, the researchers worked with East Yard Communities for Environmental Justice to collect more than 1,000 soil samples from 373 residential properties.

This figure shows the approximate locations of residential soil samples collected for the study.

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Courtesy Get The Lead Out Study

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More than two thirds of samples from remediated homes still had over 80 ppm of lead, the state’s threshold for use, with 19% of those samples reaching over 200 ppm.

The study also looked at neighborhoods outside the state’s defined cleanup area. Nearly 90% of those sampled homes were beyond acceptable levels. Seven in 10 homes had at least one sample above 200 ppm, according to the findings.

The study suggests two things for remediated homes — either contaminated soil wasn’t fully removed, and/or it was recontaminated by historically present lead, like that in paint or freeway exhaust particles.

“ We don’t think that if you adequately remove the soil from the home, that we should be seeing this much recontamination just from lead paint that’s on the exterior of the house,” Johnston said.

Another author on the study, East Yard’s mark! Lopez, an  Eastside community organizer, said the research helps affected residents, many of whom are predominantly Latino, fight against  environmental racism.

“ We’re bringing the personal narrative, the collective experience, peer review data to the table," he said. "It’s an extra layer of credibility to be able to really push the agency to do right, to push the state to do right by our communities.”

LAist has reached out to the California Department of Toxic Substances Control for comment, but did not hear back in time for publication. We’ll update this story once it’s received.

The L.A. County Department of Public Health, which participates on the Exide Technical Advisory Committee (a public forum for residents and agencies to communicate about the cleanup), said in a statement the study matters from a public health perspective.

“The findings underscore the importance of continued evaluation of cleanup effectiveness, consideration of post-remediation testing and ongoing efforts to reduce exposure,” the department added.

Calling for change

The study makes multiple policy change suggestions — some of which have already been implemented, such as third-party monitoring of cleanup crews.

East Yard Communities for Environmental Justice is calling for expanded remediation beyond the 1.7-mile boundary. They also want a commitment to resampling every cleaned up home, and if needed, correcting lead problems. He wants those results to be shared with communities in a timely manner.

As of 2025, Johnston said all new homes are getting cleaned and are getting retested. For homes cleaned prior to that, a sample of homes are being rechecked.