Majority of Altadena Homes Still Contaminated with Lead and Asbestos After Cleanup, Local Group Finds

New testing shows widespread residual contamination in standing homes after the Eaton fire

More than half of the standing homes tested in and downwind of the Eaton fire remain contaminated with lead even after professional remediation, and roughly one in three remediated homes tested positive for asbestos, according to new results released by the grassroots group Eaton Fire Residents United (EFRU).

The findings come from post-remediation lab results for 50 homes within the Eaton burn and ash-affected area. The data provide the first broader evidence that the cleanup approaches promoted by some insurers and public health guidance have not consistently removed hazardous ash deposits from indoor surfaces.

Key findings

• Of 45 homes tested for lead, 43 showed measurable lead contamination.
• Windowsill samples: 9 of 18 homes exceeded the EPA level that typically triggers further remediation.
• Floor samples: 15 of 24 homes exceeded the EPA remediation level for lead on floors.
• Asbestos: Detected in 9 of 25 homes tested; average concentrations in those homes were substantially higher than the ad-hoc asbestos benchmark the EPA used after 9/11.

Health risks and implications

Long-term asbestos exposure increases the risk of mesothelioma and other cancers. Chronic lead exposure is especially harmful to children and can cause irreversible brain damage, developmental delays, and behavioral issues. Experts emphasize that no level of exposure to either contaminant is without risk.

"This is a community-wide problem," said Nicole Maccalla, who leads EFRU's data science work. "One pass is not establishing clearance based on the data that we have, which means it is not yet safe to return to your home."

How the study was done

EFRU compiled professional sampling and certified-lab results that homeowners hired and then shared with the group. The organization prioritized reports from industrial hygienists—professionals trained to detect environmental health hazards—then aggregated the results into a database to look for patterns across multiple properties.

EFRU noted important limitations: the sample size is modest and testing practices varied. Many assessments did not test for both lead and asbestos despite public-health advisories, and some asbestos tests used less-sensitive methods that can undercount contamination.

Calls to action

EFRU is urging the California Department of Insurance to require insurers to cover post-remediation testing and, when necessary, multiple rounds of cleanup. The group is also asking Governor Gavin Newsom to declare an official "ash zone" to recognize the wider health impacts of fire smoke and ash and to ease the burden on homeowners seeking coverage.

François Tissot, a Caltech geochemistry professor who has tested standing homes after the fire, said he expected professional remediation to lower lead levels much more than EFRU's results show. "To see that we are not even breaking 50% with professional remediation is rather alarming," he said.

Without a standardized, research-backed playbook for indoor remediation after wildfires, homeowners face a patchwork of insurance adjusters and contractors using inconsistent methods. EFRU hopes to work with researchers and officials to develop indoor cleanup guidance similar to existing playbooks for drinking water and soil.

Practical guidance for residents

• Request certified post-remediation testing from qualified industrial hygienists or accredited labs.
• If test results show contamination, insist on additional remediation and retesting until labs confirm clearance.
• Document all communications with insurers and remediation contractors; consider seeking advocacy support from local groups like EFRU.

Note: The report is based on a limited set of homes and testing methods varied. Still, the results raise significant concerns that warrant coordinated public response, broader testing, and improved remediation standards.

This story originally appeared in the Los Angeles Times.