Feds will not test soil after LA fires cleanup. Experts warn more testing is needed.
The U.S. Army Corps of Engineers said it will not conduct soil sampling at private properties damaged by the Palisades and Eaton fires, raising concerns about the risks of lingering contaminants and how far hazardous ash has spread across Los Angeles County.
The aftermath of the widespread wildfires — which scorched over 37,000 acres and damaged or destroyed more than 16,000 structures — has prompted questions about the long-term health impacts of wildfire pollution as communities set their sights on rebuilding.
Recent research has shown that severe wildfires can cause chemical changes in soil, affecting water contamination, air quality, and plant growth. Federal and state agencies have previously tested soil after major wildfires to confirm that contamination levels are at the acceptable limit.
On Wednesday, the Army Corps said there will be no soil sampling for its private property removal program. The decision was first reported by The Los Angeles Times, which noted that soil sampling was not authorized for this disaster response.
"Phase 2" of cleanup and recovery efforts in wildfire zones began this week with crews removing remaining contaminated ash and debris, according to the Army Corps. As part of the debris removal step, crews will also extract concrete foundations and the top six inches of soil in fire-impacted areas.
"We're removing six inches of topsoil that's within the ash footprint," Army Corps Col. Eric Swenson said during a news conference. "We're confident we'll capture any of the surface hazards that landed on the soil."
Experts and health officials told USA TODAY Thursday that while the Army Corps’ decision is a practical and standard approach, further testing needs to be done to help communities understand potential risks and determine the scope of the problem.
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'Sensible to request confirmation soil testing after debris clean up'
In previous years, federal and state agencies have conducted confirmation soil sampling for large California fires, according to the Los Angeles County Department of Public Health. The technique is used to verify that soil remedial objectives are met and contaminants do not exceed state standards.
Sanjay Mohanty, an associate professor in the civil and environmental engineering department at UCLA, cited the 2018 Camp Fire that largely destroyed several communities in Northern California’s Butte County. He noted that the response for the Camp Fire had been different, in which crews measured the concentration of pollutants in the soil before and after cleanup operations.
"Measuring the concentration of pollutants will tell them what kind of cleanup goal they should have," Mohanty said. "After they clean up and do the remedial actions, they want to make sure that they actually achieve that. So that's why they do testing twice, at least in the last Camp Fire."
Mohanty called the Army Corps' decision to excavate six inches of soil a "very practical approach." He explained that most pollutants are trapped within the top six inches of soil and once those six inches are removed, it is believed that no residual pollutants will remain in the soil.
But more testing and data are still required to identify whether the risk of contaminants has been eliminated, Mohanty said, warning that soil contamination may remain in hilly areas and can also be carried by rain waters.
In response to the Army Corps’ decision, the Los Angeles County Department of Public Health said it has compiled other "post-fire air, soil, and water risk assessment activities conducted by various agencies and academic institutions." The department added that the assessment plan is updated weekly and results will be shared with the public on its website as they become available.
"Given the magnitude of the disaster, it is sensible to request confirmation soil testing after debris clean up, particularly given the amount of fire debris generated by both fires," the department said in a statement.
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Lead already detected in street dust
Los Angeles faces unprecedented environmental issues from the toxic fallout of the fires, including hazardous ash settling in backyards and playgrounds, USA TODAY previously reported.
Researchers from USC recently tested street dust in neighborhoods devastated by the Eaton Fire. Toxic heavy metals — such as lead — that may have spread across the region have been a concern, according to Sam Silva, an assistant professor of Earth Sciences, Civil and Environmental Engineering and Population and Public Health Sciences.
Thousands of buildings near the Eaton Fire were destroyed, and older buildings often contain lead-based paint, lead pipes, and lead-contaminated dust. Research has also indicated that lead can linger in the soil and air.
"What we found was fairly consistent with what a lot of scientists might think, which was that the lead itself did not travel extremely far across L.A.," Silva said. "But there were high concentrations of lead in the urban burn scar — the area of Altadena directly adjacent to homes that burned down."
Silva noted that lead exposure can cause serious health problems, such as neurotoxic effects.
"Lead in the soil doesn't go away after a week. It takes an enormously long amount of time for it to actually go away," Silva said. "Because of that, we have to remediate it through other mechanisms, and often this includes just removing that sort of top six inches of soil to get rid of the lead."
State and local officials tout recovery process speed
The Army Corps is leading cleanup and recovery efforts in coordination with state and local partners. State and local officials have called phase two of the operation a critical step in recovery efforts.
Though communities are far from rebuilding, Los Angeles County Board of Supervisors Chair Supervisor Kathryn Barger emphasized that the beginning of the debris removal process is a "milestone."
"It shows that we are working together on an accelerated timetable to restore our facilities and communities as swiftly and safely as possible," Barger said in a statement. "We need to keep this momentum going so that residents can tangibly see, hear, and feel rebuilding progress is underway."
California Gov. Gavin Newsom and Los Angeles Mayor Karen Bass have also signed executive orders to cut red tape and streamline recovery and rebuilding operations.
Thousands of residents have submitted Right of Entry forms, which allow the Army Corps to clear debris from private properties for free, KABC-TV reported earlier this week. Of those residents, only 315 people have opted out of the program.
Contributing: Megan Smith and Trevor Hughes, USA TODAY
This article originally appeared on USA TODAY: Los Angeles fires: Experts say more soil testing needed after cleanup