The fires in Los Angeles destroyed 14,000 structures, and the EPA cleanup is now underway with 75% of the hazardous material being cleared in the last three weeks. Many are left wondering if it is safe to rebuild after such devastation and destructive chemicals seeped into the soil of 13,595 residential properties and 305 commercial properties that were impacted.

Science Behind Lithium-Ion
A major component of the cleanup is the removal of lithium-ion batteries and the dangers that they can impose. According to ClemsonNews, one factor is a 20% increase in the battery's temperature causes some unwanted chemical reactions that lead to the release of excessive heat. The excess heat then increases battery temperature and speeds up reactions which can cause the battery to burst and release gases in an event called thermal runaway which then can cause gas release, violent combustion, and explosion.

 
Further, after a large fire burned at a battery plant in Monterey County, California, in January, scientists at San Jose State University discovered that there are heightened levels of unusually high concentrations of heavy-metal nanoparticles in the soil at Elkhorn Slough Reserve. The heavy metals included nickel, manganese, and cobalt. This raises concern regarding soil safety.

"We don't know the long-term effects of all this exposure, and we haven't seen this on this large of a scale and this many electric vehicles," Los Angeles City Fire Capt. Adam VanGerpen told KNBC. "This is an unprecedented amount of electric vehicles with lithium-ion batteries in there."

With that in mind, this fire is different than any previous event as according to CalMatters, 25.7% of all new cars in the state were electric vehicles. Further, they are a major source of lithium-ion and there has been a significant number of these types of batteries caught in the fires.

Alluvial Soil Lab Soil Scientist and Consultant Jake Pinkus told LASN that the recent wildfires in L.A. have had devastating consequences but that depending on the materials burned and the movement of contaminants, soils may be affected by heavy metals, volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs). This means that the pollutants pose safety risks and can disrupt plant growth due to altered pH or nutrient imbalances.

Helpful Tips
The University of California Agriculture and Natural Resources says that contaminants detected post-fire in a soil test don't determine what the soil was like before the fire. Yet, Pinkus says that complete soil removal may be the most effective remediation strategy but alternative methods like phytoextraction - a form of phytoremediation that uses plants to absorb and store heavy metals - can also be considered. He went on to say that certain plant species like Indian Mustard (Brassica juncea), Sunflower (Helianthus annuus), Brake Fern (Pteris vittata), Willow (Salix species), and Sedum (Sedum alfredii) are known for their ability to extract contaminants from the soil.

According to Natalie Levy, Ph.D., Soil Health & Organic Materials Management Advisor at University of California, Agriculture and Natural Resources Cooperative Extension, fire damage can have an impact on the microbiology, chemistry, the properties, and structures of the soil.

Dr. Levy said that there are a diverse number of ways to look at remediation including compost, organics, and soil removal but that health is the number one priority.