Soil in properties downwind from the Eaton fire burn zone did indeed have soil containing lead levels above health-based screening thresholds, Los Angeles County Public Health officials said late Friday, Sept. 12, in the agency’s final findings on the matter.
The findings confirmed reports from April, when preliminary testing showed elevated percentages of lead levels in soil samples taken from sites with still-standing homes downwind from the Eaton fire area that were a notch above public health thresholds.
The results prompted public health experts to urge caution. And while the message was tempered with the need for more study, it sparked similar testing in the Pasadena Unified School District.
That testing, too, detected elevated levels of lead, arsenic, chromium, Polycyclic aromatic hydrocarbons (PAHs) and dioxins/furans among 18 PUSD sites that had at least one area of elevated levels of harmful substances.
Friday’s results came from representative soil sample testing in and around the Eaton and Palisades fire areas.
Roux Associates, Inc., which conducted the samples for the county, was searching substances such as heavy metals, polyaromatic hydrocarbons (PAHs), and dioxins/furans.
Public Health officials said that the final findings also confirmed “localized chemical impacts to soil above health-based screening thresholds are present in the Palisades fire area, but there is no evidence of widespread contamination from fire-related chemicals.”
“Those with concerns about their specific property may want to test their soil and/or consult an environmental professional about evaluating their property,” Public Health said in a release announcing the findings. “In all areas with ongoing fire debris, residents are reminded to take precautions to not inhale, ingest, or come into contact with ash, soot, and/or fire debris by using appropriate personal protective equipment.”
Officials noted that it was not clear if the contamination in the soil was fully because of the Eaton fire.
“There are many potential sources of lead in soil in the Los Angeles area (and) additional assessments may help understand how much of the lead found in the samples came from the 2025 wildfires versus other sources,” Public Health officials said.
The testing was in an area known as the Eaton Fire Region, consisting of 70 sampling grids, with 23 of those grids containing intact homes (i.e., Minor/Affected Parcels, No Damage Parcels, Outside Fire Boundary Parcels), according to Public Health.
Of the 23 grids for parcels with intact homes, 10 had average grid concentrations greater than the California Department of Toxic Substances Control’s (DTSC) residential soil screening level thresholds of 80 milligrams per kilogram (mg/kg).
“That was consistent with reports of elevated lead in air samples collected in the days immediately following the fire,” officials said.
Officials said the source of that lead is “reasonably expected” to come from the burning of homes with lead-based paint. Such paint coatings were common before 1979, a fact echoed by USC’s Lusk Center for Real Estate, which reported that more than 70% of the houses within the Eaton Fire Region were built before 1979.
Officials said the average grid concentration found in the testing within the 10 grids that exceeded the residential screening level ranged from 80.2 mg/kg to 167 mg/kg, officials said.
Authorities noted that destroyed sites cleared by the Army Corps of Engineers in both Palisades and the Altadena area showed “significant reduction in the potential health risk where soil removal occurred.” But the results did show that the parcels could still have areas where the concentration of chemicals in soil exceed residential screening levels.
“Some of these observed soil impacts may be unrelated to fire-related smoke and ash,” authorities said. “Soil handling and management during rebuilding should consider how best to manage surface soils to prevent exposure to impacted soils during construction as well as in final landscaping design/installation.”