Soil Toxicity
“Are my soils toxic?” “Can I rebuild?” “Will my home be safe?”
Here’s what you need to know according to the scientists leading the research.
*This information has been checked for accuracy by Dr. Sanjay Mohanty, UCLA, lead researcher at Cap.LA. Consult with a licensed professional about your specific situation.
The basics
When a home burns, materials like car batteries, lead paint, major machinery, and appliances create a noxious cloud of dangerous substances. Unfortunately, once the tractors are gone, many of those chemicals can persist in soils.
Unless you arranged private debris removal, there’s a chance your land still holds contaminants that could affect your family’s health and the value of your property.
What are
the toxins?
Post-megafire contaminants can include lead, arsenic, asbestos, hexavalent chromium, Polycyclic Aromatic Hydrocarbons (PAHs), Volatile Organic Compounds (VOCs), and other worrying substances.
What Are The Dangers?
Here is a rundown of the risks of some of the main contaminants that can be present after wildfires.
Note: Some of these substances are naturally occurring or were already present in soils, pre-fire. What to keep an eye on are when levels exceed safety thresholds, and the duration of exposure needed for dangerous effects to occur.
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Lead, especially, is dangerous for kids and pets - it can be tracked in on shoes, licked off paws, or spread through dust.
Can damage the brain: trouble with learning, thinking, and memory, especially in young children, as their brains are still developing.
Can weaken blood production → possible anemia (less oxygen in the body).
Can cause digestive and nervous system issues: upset stomach, weakness, tremors.
Builds up over time - small exposures can accumulate and cause harm because the body doesn’t get rid of lead quickly.
Source: National Library of Medicine
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Skin problems: patches, discoloration, hard or thick areas.
Increased risk of cancers (skin, lung, bladder) with long-term exposure.
Harm to organs: liver, kidneys, and heart can be damaged over time.
In children, slow growth or developmental delays may occur if exposed early or for a long period.
Source: World Health Organization and National Library of Medicine
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If fibers are breathed in, they can lodge in the lungs permanently. Over years, this can lead to lung scarring (asbestosis), difficulty breathing.
Causes cancers like mesothelioma (lining of the lungs or chest cavity), which is very serious.
Pets are also at risk — dogs, cats (and other animals) can develop mesothelioma when exposed to asbestos fibers.
Source: CDC, Agency for Toxic Substances and Disease Registry, and Animal Health Foundation
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Recognized as a strong carcinogen when inhaled: increases risk of lung cancer.
Can cause skin irritation, ulcers, and respiratory allergic reactions if one comes into contact via air or dust.
Source: Cal OEHHA, National Library of Medicine, OSHA, National Institute of Environmental Health Sciences, US EPA
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Many PAHs are carcinogenic or suspected carcinogens (linked to cancers).
Can cause respiratory problems: inflammation of airways, worse asthma or coughing.
May harm unborn babies / cause low birth weight when pregnant people are exposed.
Source: National Library of Medicine, Agency for Toxic Substances and Disease Registry
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Short-term effects: irritation of eyes, nose, throat; headaches; dizziness; nausea.
Long-term: some VOCs damage the liver, kidneys, or the central nervous system. Some are possibly or definitely cancerous.
Pets are also sensitive: breathing problems, behavioral changes could result from high exposure.
Source: American Lung Association
How Contamination
Can Affect
Property Value
By law, you must disclose past fire damage and known contamination when selling a property in California. When an area has gone through as widely publicized a disaster as ours, buyers, lenders, and insurers will already know that the area was affected and can ask for proof that your soil is clean. If you can’t provide it, you may face lower offers, delays, or outright refusals.
Note: By this same token, be aware that if your property tests positive for contaminants, you are required to disclose that in the event of a sale. If you have not properly remediated, it could affect your property value or ability to sell.
What You
Should Do
After the LA fires, the Army Corps of Engineers only removed six inches of soil beneath (and 3 feet around) structures larger than 120 square feet. It’s important to confirm the safety of the rest of your lot.
Testing is the only way to know your land is truly safe for you, your family, and anyone who may live there in the future.
1. Check your debris removal paperwork
If you used a private debris removal contractor, look for a lab report showing results for CAM17 heavy metals (and ideally PAHs). If there is no lab report, you likely did not receive clearance testing. The Army Corps of Engineers debris removal program did not perform any soil testing in Los Angeles.
2. Arrange professional testing
Hire a certified lab to come on-site and collect samples. Experts recommend that you don’t rely solely on self-submitted samples if at all possible. Recommended testing includes:
CAM17 heavy metals
Lithium
Cr6 (Hexavalent Chromium)
PAHs (Polycyclic Aromatic Hydrocarbons), if available
Ask the lab to include chain-of-custody documentation with your results.
TIP 1:
If you are part of a lawsuit (like against SCE), ask your attorney if they are planning to perform soil tests and/or if they will cover the cost under your case costs. You will have to pay for this out of any settlement you receive, but it can save you some up-front costs.
Many residents have also had success getting reduced costs by bundling testing services with neighbors. Ask the lab if they’d be open to that!
TIP 2:
If you are unable to access professional testing, you can self-submit samples to USC’s free CLEAN program, but a few things to note:
Because these tests involve only up to 2 composite samples, a negative result from this program should not be taken as an indication of a fully safe lot.
To obtain a remediation plan, a professional test will be necessary.
A self-submitted test will not suffice for legal claims for damages, so if you plan to claim the cost of testing or remediation, a professional test with chain-of-custody will be required.
What are
“exceedances”
If the level of contamination and duration of exposure are the big factors here, the baseline metric for concern is what levels of contamination the California EPA and DTSC say are potentially harmful.
Those agencies set a threshold for what level of contamination is normal and safe for humans to live with, vs when we need to be worried. An “exceedance” means the levels are higher than is considered safe for humans.
If Your Soil
shows exceedances
Hire a Certified Industrial Hygienist or Residential Soil Specialist
They will prepare a remediation plan and make recommendations on how to proceed.
Perform Remediation
Your Hygienist or Specialist may recommend scraping and replacing soil, bioremediation, or other methods, depending on the extent of your contamination. They should also be able to point you to an Environmental Remediation Contractor to perform the cleanup.
Don’t just
cover it
Experts strongly advise against “capping” toxic soil. Heat and digging can bring contaminants back to the surface.
How Much Does
Remediation
Cost?
Remediation costs vary depending on the size of your lot and the level of contamination. Some survivors have been able to include remediation expenses in lawsuits, and some attorneys may arrange and pay for testing upfront. Neighbors may also be able to negotiate group rates with labs.
What Your
Neighbors Do
Matters… A Lot.
If your neighbors don’t remediate toxic soil, contaminants can spread onto your property through:
Rainwater runoff – Water flows downhill, carrying fine, contaminated particles with it.
Wind - Dry, dusty soil can blow across property lines.
Shared landscaping or drainage - Especially if you have adjoining yards, irrigation, or a natural slope.
This is why:
A single property testing clean doesn’t guarantee it will stay that way long-term if neighboring lots are still toxic.
Buyers or insurers might raise red flags if adjacent lots didn’t test or remediate, especially in fire-damaged zones.
Want to reach
your neighbors?
Bottom line
Having your soils professionally tested is an important step for your health, your rebuild, and your property value. Save your results and request a clearance letter - it will serve you now and in the future.
Some Labs
That Perform Testing
in LA County
MACS Lab Inc - (833) 522-6227
LATesting - (800) 303-0047
Torrent Laboratory, Inc - (408) 263-5258
Find LA City’s list of Environmental Consultants here.
*PostFire does not endorse or receive a listing fee from any of these labs. Hire and proceed at your own discretion.