Why Post-Fire Soil Sampling Matters — And How to Do It Smartly

Dr. Bart Sokolow is President of Environmental Advisors, Inc., and writes about environmental issues, with an emphasis on resolving conflicts related to toxic and hazardous chemicals. In a VX News Op-Ed, Sokolow shares ten points to keep in mind for the post-fire soil sampling process, which includes reminders to check for car location, household and pool chemical storage, Asbestos, and more.

“Soil testing may sound technical—but it’s ultimately about your safety. Identifying potential contamination hotspots allows you to make informed, confident decisions about rebuilding, returning, or staying.”

In recent weeks, I’ve had thoughtful conversations with Dr. Stephen Baruch and Dr. Edward Faeder, both of whom bring deep insight into post-disaster recovery. One theme keeps surfacing: If your home was impacted by the recent fires, soil sampling should be on your radar.

The aftermath of a wildfire is chaotic and emotional. There’s so much to manage, and understandably, soil testing might not feel urgent. But here’s the reality: after the flames are gone, hidden hazards can remain—especially in the soil beneath your feet.

There’s been increasing scrutiny of the Army Corps of Engineers’ cleanup protocols—especially regarding their removal of the top 5–6 inches of soil on fire-damaged properties. Many homeowners have asked: Was it enough? Was it tested properly? In many cases, the answer is: probably not.

And that’s where post-remediation soil testing comes in. When done strategically, it isn’t just good science—it’s good sense. It can help you protect your health, your home, and your future.

Here’s a practical walk-through of where to look, what to document, and why it matters—whether your house was destroyed or is still standing.

1. Car Location and Battery Hazards

Where was your car parked during the fire? If it was burned or heavily damaged, especially if it was electric or hybrid, there may be lingering contamination from lithium-ion or lead-acid batteries. These can leach hazardous metals into the soil. Don’t touch the area—just document it for targeted sampling.

2. Medicine Cabinet Area

Was your medicine cabinet reduced to ash? Burned pharmaceuticals can create toxic byproducts. Pharmaceuticals can react and form harmful new chemicals when burned and may pose contamination risks transferred into the surrounding soil. Try to pinpoint where the medicine cabinet was and flag the area for testing.

3. Chemical Cleaners

Did you store bleach, Draino, hydrogen peroxide, or other household cleaners? When exposed to high heat, these chemicals can become toxic. Make note of these storage areas for targeted soil sampling.

4. Sprinkler Systems & PVC Pipes

PVC pipes, commonly used in lawn sprinkler systems, are made from polymerized vinyl chloride, a known human carcinogen. When PVC burns, it can release vinyl chloride, and form toxic chemicals, including dioxins, phosgene, hydrochloric acid, and carbon monoxide into the air and soil. Harmful levels can be present in untreated or unremoved soil.
Find and mark the locations of your anti-siphon valves and buried PVC sprinkler lines, often located near your home’s exterior.

5. Pool Chemical Storage

If you stored chlorine tablets or pool shock treatment on-site, they could also have left behind contamination when burned. Add those locations to your sampling checklist.

6. HVAC Systems and Air Ducts

Even if your home didn’t burn down, smoke infiltration is a real issue. Air ducts can trap particulate matter. Consider a professional HVAC cleaning and upgrade to HEPA or activated carbon filters to improve your indoor air quality.

7. Asbestos Warning Signs

Homes built before 1980 may contain asbestos in tiles, adhesives, and even window grout. Fire can release these fibers into the air and soil. Look for remnants of 9”x9”, 12”x12”, or 18”x18” tiles— These tiles — and the black mastic (glue) used underneath — can release asbestos fibers when burned. Asbestos can also be present in wall board and window grout. Be especially cautious in identifying and testing these areas or consult with a professional to identify potential asbestos hotspots…

8. Access Pathways

Think about your usual route into the house—what do you walk over and bring inside? Retrace this path and consider it a conduit for soil pollutants to enter your living space. This is often the same route that outdoor soil contaminants can travel indoors. Being aware of this pathway is a simple but important step toward minimizing the risk of tracking pollution into your living space.

9. Has the House Really Been Cleaned?

Attics. Furniture. High-touch surfaces. Even if the home looks clean, residue can persist in less obvious areas. These are all potential high-contact areas—and they may also be a source of long-term exposure risks. It’s important to consider where people may come into contact with surfaces or breathe in lingering contaminants. Simply being mindful of these areas is the first step, and it's worth discussing them with an exposure professional.

One more critical point: When we oversee cleanup protocols, we often recommend a follow-up inspection by a third party—someone who was not involved in the actual cleanup. Post-cleanup inspections by a third-party professional (not involved in the original cleanup) offer a second layer of certainty. This isn’t about paranoia—it’s about protecting your family. This independent verification ensures the work was done thoroughly and correctly. After all, this is your home. Confirming that it's truly clean isn’t just about peace of mind—it’s about protecting your health, and that of your family and visitors.

10. Don’t Forget the Yard

Whether it’s backyard barbecues or vegetable gardening, the soil you and your family come in contact with matters.. Do you dig in the soil, plant a garden, harvest vegetables, or pick flowers? These are all high-contact activities that may pose long-term exposure risks if the soil is contaminated. Such areas should be carefully considered—and tested, when appropriate—after consulting with an exposure professional.

Choosing the Right Help

We use the term “exposure professional” broadly. In our experience, Certified Industrial Hygienists (CIHs) bring the right mix of experience and credentials, but they’re not the only qualified experts. The key is working with someone who understands the long-term risks and how to interpret soil data meaningfully.

Final Thoughts

Soil testing may sound technical—but it’s ultimately about your safety. Identifying potential contamination hotspots allows you to make informed, confident decisions about rebuilding, returning, or staying.

Not sure where to start? Reach out to an environmental engineer or soil remediation expert. Even a short consultation can help you understand your next steps—and whether formal testing is necessary. While Certified Industrial Hygienists are a safe bet, use your judgement. And remember: identifying these hot spots now can help safeguard your health, your home, and your family for years to come.

Bart B. Sokolow, D.Env., P.E., President of Environmental Advisors, Inc., is a former UCLA Professor of Environmental Science & Engineering; he has advised various industries with respect to environmental matters for nearly 30 years. Dr. Sokolow also co-authored “How To Avoid Environmental Litigation - Second Edition” available on Amazon, Bart Sokolow's Environmental Risk Substack and the YouTube channel, The Environmental Minute -“Navigating the Environmental Risk in Real Estate.