Post-fire soil hazards: recommendations for updated soil testing protocols and clearance thresholds

Area of Science:

• Environmental Health
• Toxicology
• Urban Planning

Background:

• Urban wildfires in Los Angeles elevate soil lead exposure risks, particularly for children.
• Existing post-wildfire soil remediation protocols may not adequately safeguard public health in affected communities.

Purpose of the Study:

• To assess the effectiveness of current soil remediation practices following urban wildfires in Los Angeles.
• To propose policy recommendations aimed at mitigating lead exposure risks.

Main Methods:

• Review of California's wildfire debris removal protocols, soil testing procedures, and lead exposure health benchmarks.
• Analysis of recent post-fire soil testing data and the scientific basis for California's Preliminary Remediation Goal (PRG) for lead.

Main Results:

• Over 20% of properties exceed lead thresholds even after remediation, indicating protocol inadequacy.
• California's current residential soil lead PRG of 80 mg/kg is not health-protective, lacking adherence to toxicity benchmarks and current scientific understanding of child lead exposure risks.

Conclusions:

• Critical gaps exist in post-wildfire remediation, leaving Los Angeles residents, especially children, vulnerable to lead exposure.
• Policy reforms, including mandatory confirmatory soil testing and a reduced PRG to 55 mg/kg, are essential for enhanced environmental health protection.
• Implementing these measures offers a safer future for communities impacted by escalating urban wildfire threats.