Post-Palisades Fire study: ocean clean, but lead lingers in soil Play

Beach users encountered toxic chemicals in the ocean immediately following the Palisades Fire in Malibu. But the good news: fire-related chemicals that washed into the ocean off Malibu and the Pacific Palisades have pretty much dissipated.

The bad news: lead is still being found in the dirt in some fire-damaged neighborhoods.

That’s according to a major study done by a consortium of universities led by USC. The Contaminant Level Evaluation and Analysis for Neighborhoods project, known as CLEAN, has just been released. It consolidated the work being done by a half dozen major universities all doing research into ground contamination after the January 2025 Palisades fire.

Researchers analyzed more than 6,000 soil samples collected from more than 3,000 locations, and more than 900 seawater samples.

The ocean is now clean. The land, not so much.

Lead was found in the soil at numerous sites, but researchers said it is impossible to determine if that was caused by the fire, or was preexisting from decades of lead-based paint and leaded gasoline used by cars and airplanes.

The report found no evidence of countywide post-fire contamination from other metals that generated concern after the fires, including arsenic, mercury and hexavalent chromium.

But lead levels varied dramatically, even from samples collected in close proximity to each other. One soil sample could contain as much as twice as much lead as another collected just a few feet away. Researchers said the findings underscore the importance of testing individual properties.

The CLEAN Waters team monitored Southern California beaches and coastal waters for 18 months. Their finding: nutrients, metals and hundreds of fire-related compounds increased in the weeks after the fires before returning to more typical levels within several months.

“The fires left a clear signal in the ocean, but it wasn’t a permanent one,” said USC Assistant Professor Noelle Held.

Researchers also released a home and yard guide to help residents reduce potential exposure to contaminants. The guide can be found at https://www.consortium-science.com/.