What is Known?
Air quality monitoring during the active fires showed elevated levels of lead in the air. Testing of firefighters found higher blood lead levels than their counterparts. Recent soil testing has revealed that a significant number of homes, including those outside the burn area, have lead levels that exceed existing screening thresholds.
What Did We Do?
In response to community concerns and questions about determining ‘safe’ levels of lead in soil after the L.A. fires, our team evaluated existing lead soil testing strategies and cleanup thresholds.
What Are We Recommending?
We recommend two critical reforms:
- Require post-clearance confirmatory soil testing after wildfire cleanup. This step has been standard practice for every major wildfire in California since 2007.
- Lower California’s residential Preliminary Remediation Goal (PRG) for lead in soil from 80 mg/kg to 55 mg/kg to reflect updated science and more health-protective standards.
Why Is This Change Needed?
Repeated testing after soil remediation has shown that over 20% of properties still have lead levels exceeding existing thresholds. Additionally, the current 80 mg/kg PRG:
- Does not adhere to the health-based toxicity benchmark set by California
- Is subject to high uncertainty due to several exposure factor values used in the calculations
- Does not accurately reflect our current understanding of the risks that lead poses to children
Is Everyone at High Risk?
A PRG of 55 mg/kg is a soil remediation level below which no further action is needed for full use of the site; levels above this should be remediated. These values are intentionally designed to protect children, who are more vulnerable to lead exposure due to their higher likelihood of coming into contact with soil. Adults, who typically have less exposure to soil, are at lower risk. Additionally, these exposure assumptions are based on bare, exposed soil; if there is ground cover or a layer of fresh topsoil, the risk of exposure will be lower.
IF YOU HAVE OTHER POTENTIAL SOURCES OF LEAD WHERE YOU LIVE, FOR EXAMPLE, LEAD-BASED PAINT, ADDITIONAL ANALYSIS IS REQUIRED
This PRG does not account for other potential sources of lead exposure within a residence. If additional sources are present, a site-specific risk assessment may be warranted, as noted by DTSC:
“Because the lead benchmark dose is an incremental change in blood lead, background exposures to lead, and media other than soil, or dust from the site, which may be impacted by lead, are not considered in the worksheet. If lead is present in media other than soil (e.g., water, air) or if the homegrown produce pathway is anticipated at the site, please contact the HERO toxicologist assigned to the site.“
What Can I Do?
In addition to remediating soil, the following individual actions can help reduce exposure to lead:
- Wash hands frequently, especially before eating.
- Remove shoes when entering your home.
- Clean your pets’ paws before they come indoors.
- Keep indoor surfaces clean.
- Damp-wipe dirty surfaces, especially playroom floors, carpets, and foam or rubber mats where children play.
- Use a vacuum with a HEPA filter.
- Increase indoor air filtration:
- Upgrade to MERV-13 filters in your central HVAC system, if possible.
- Use portable air cleaners with HEPA filters.
Read the full Perspective here: