LOS ANGELES — Seventeen months after the Palisades and Eaton wildfires consumed more than 16,000 structures across Los Angeles County in January 2025 — incinerating homes, vehicles, electronics, solar panels, and decades' worth of synthetic materials — families are returning to their properties and rebuilding. Many are doing so without ever being told whether the soil beneath their rebuilt foundations has been tested for the toxic heavy metals, carcinogens, and persistent chemical contaminants that wildfire research consistently shows are left behind when modern structures burn.

The reason is a decision that has now been documented in the Journal of Exposure Science & Environmental Epidemiology, challenged in letters from California state lawmakers, and reported by the Los Angeles Times and CalMatters: the U.S. Army Corps of Engineers and FEMA agreed to remove hazardous ash and up to six inches of topsoil from destroyed properties — but decided not to perform post-remediation confirmatory soil testing. That decision broke with precedent established during every major California wildfire cleanup dating back to the 2018 Camp Fire. And it has left an unknown number of the 13,500+ properties damaged or destroyed by the Palisades and Eaton fires with no verified confirmation that their land is actually safe for human habitation.

What Burns in a Modern House — And What It Leaves Behind

When a 21st-century home burns, it does not burn clean. Modern construction materials, furnishings, finishes, and consumer goods contain a chemical complexity that fire transforms into a toxic legacy. Lead vapor released from paint, electronics, and plumbing fixtures settles into soil and ash. Arsenic, used as a wood preservative in older structures, concentrates in burned debris. Benzene and polycyclic aromatic hydrocarbons (PAHs) — known carcinogens — are produced by the combustion of plastics, synthetic fabrics, and treated lumber. PFAS "forever chemicals" from non-stick cookware, stain-resistant upholstery, and firefighting foam persist indefinitely in soil and groundwater.

The Palisades and Eaton fires, driven by winds gusting above 70 miles per hour, dispersed ash and particulates across a massive geographic area — potentially contaminating properties miles from the fire perimeter. The fires burned not just homes but vehicles, garages filled with chemicals, solar panel arrays (which contain lead and cadmium), and commercial structures. Each category of material contributes its own suite of toxic combustion products.

Independent soil testing performed by the Los Angeles Times, after federal agencies declined to mandate testing, found lead levels in fire-affected soil that exceeded California's residential safety threshold of 80 parts per million (ppm) in multiple locations. Researchers publishing in the Journal of Exposure Science & Environmental Epidemiology have urged the state to reduce the residential screening threshold for lead from 80 ppm to 55 ppm based on new evidence — arguing that children can be harmed at soil lead concentrations below the current California standard.

The FEMA Decision: A Break from Decades of Precedent

"FEMA's refusal to test for toxins in the soil after wildfire cleanup in Los Angeles County is unacceptable," said California Assemblymember Laura Friedman. "Families deserve to know their homes are safe and free of dangerous chemicals. This is a break from decades of FEMA precedent — and it risks exposing entire communities to long-term health threats." The statement, reported by multiple California news outlets and CalMatters, reflects a growing coalition of state lawmakers, environmental health researchers, and affected residents who argue that the decision to skip post-remediation testing created a public health liability of unknown but potentially enormous scale.

The Army Corps's rationale — that removing six inches of topsoil is sufficient to eliminate hazardous pollution — conflicts with the evidence from previous California wildfire cleanups. After the 2018 Camp Fire, which destroyed the town of Paradise, post-removal soil testing found dangerous levels of contaminants remained in properties where topsoil had already been removed, requiring additional remediation. That experience informed the precedent of testing — a precedent explicitly abandoned for the Los Angeles fires.

Research published in the PMC-indexed wildfire study further explains why a six-inch removal cannot be considered a reliable remediation standard: wildfires create unpredictable contamination "hotspots" at varying soil depths, and ash and debris disturbed during cleanup operations can migrate contaminants deeper into the soil profile. Testing only the surface layer after removal does not capture contamination that may have already moved beyond the removal depth.

Who Is Most at Risk — and the Populations Being Left Behind

The demographics of the communities affected by the Palisades and Eaton fires add another dimension to the public health concern. Altadena, one of the hardest-hit communities in the Eaton Fire burn zone, is a historically Black middle-class neighborhood with deep roots in Los Angeles County. Pacific Palisades, destroyed by the Palisades Fire, is among the wealthiest communities in Los Angeles. The absence of soil testing affected both — suggesting this is not simply an environmental justice story about race and income, but a systemic failure that crosses demographic lines.

Children who play in contaminated soil are at the highest risk of lead exposure — through hand-to-mouth contact, through dust inhalation, through vegetable gardens planted in contaminated ground. Pregnant women are at risk of lead mobilization from their own bone stores if they ingest lead-contaminated dust or produce. The long-term consequences of lead exposure — cognitive impairment, behavioral problems, cardiovascular disease — are irreversible. There is no treatment that reverses lead-induced neurological damage in a developing child.

What LA Residents Returning to Fire-Affected Properties Must Do

Given the absence of federal confirmation that post-fire soil testing has been completed, LA County residents returning to or rebuilding on fire-affected properties should take these precautions:

• Request independent soil testing before beginning any construction, landscaping, or gardening. Multiple organizations in LA County are providing testing or connecting homeowners with testing resources, including the LA County Department of Public Health and academic research groups.

• Do not let children play directly in bare soil on or near fire-damaged properties until testing results confirm it is safe. This includes properties that survived the fire — wind-driven ash may have deposited contaminants on intact parcels far from the fire perimeter.

• Do not plant food gardens in fire-affected soil without testing. Lead and arsenic can be absorbed by root vegetables and leafy greens.

• For soil testing resources and guidance specific to the Palisades and Eaton fire zones, visit the LA County Department of Public Health Environmental Health site and CalMatters' wildfire soil testing resource guide.

Conclusion: Rebuilding on Untested Ground Is Not a Recovery — It Is a Risk Transfer

When federal agencies decide not to test soil after a wildfire cleanup, they are not eliminating the contamination risk. They are transferring it — from a traceable government responsibility to an invisible private burden borne by individual families who may not know the risk exists, cannot afford independent testing, or are simply trusting that if rebuilding is being permitted, the ground beneath must be safe. That trust is not warranted without the testing that would verify it.

The Los Angeles fires of January 2025 were among the most destructive in California history. The rebuilding effort is being described as the largest in the state's history. Allowing that rebuilding to proceed on soil that has not been adequately tested — in defiance of precedent established after every major previous California fire — is a public health gamble being played with the health of tens of thousands of residents. California lawmakers, public health researchers, and affected communities are right to demand better. They should not have to.

▌ RELATED ON MEDICALDAILY.COM

→ LA Wildfire Soil Contamination: What Independent Tests Are Finding

→ Lead in Fire Ash: The Hidden Hazard After Every Urban Wildfire

→ PFAS and Wildfire: Why "Forever Chemicals" Are Concentrating in Fire-Affected Soil

→ The Camp Fire Precedent: What Soil Testing After Paradise Taught Us