by Dave Gold, CIH CSP

President, Gold Health and Safety Consulting, Inc.

December 4, 2025

I’d like to share with you Gold Health and Safety Consulting’s experience from sampling over 375 homes since MLK day in January 2025, and what we have learned. We are using this knowledge to inform our recommendations for post-remediation testing. This may be more information than what some people wish to read, but we’ve got clients that have wanted to know everything in detail.  So here goes!

• As expected, we have seen lots of wildfire contamination in people’s homes (referred to as secondary wildfire contamination). The contamination has consisted largely of  two different things – particulate debris and smoke odor. There’s been a wide variety in the extent of the damage in homes, which has to do with how close the home is to where the fires were, and how tightly the windows and doors were sealed. We’ve seen homes with little to no discernable contamination, while some homes had the interior almost entirely covered with debris.
• In nearly all cases, testing the debris for evidence of combustion residue yielded positive results. This residue, known as char, are bits of burnt material. I pointed out in my February 2025 article on wildfire response that this alone would be the lynchpin of getting insurance coverage for remediation. Further lab analysis of the debris is expensive, and unnecessary to prove the house needs remediation. Also, a limited number of samples per home is fine – just enough samples to prove that the home was impacted is enough to get the job done.
• The debris in most cases absolutely contains heavy metals contamination – namely lead, although there may also be small amounts of other metals of concern.  The lead contamination seems to be largely limited to the heavier debris that fell around entry points to homes (doors, windows, attic vents, etc.). We found that the lead contamination did not spread much beyond areas where the heavier debris landed. Furthermore, as one would expect based on its physical properties (namely the fuming and boiling points), lead did not enter homes as a vapor, and soak into things such as mattresses, clothing, and soft toys. So, unless heavy debris fell on any of these types of items, they are not likely to contain lead. Houses with light impact mostly had little to no lead contamination. We saw some homes in areas such as the Palisades Highlands and the La Vina subdivision in Altadena, that had little combustion debris deposition and no lead contamination.
• We have consistently found arsenic with the heavier debris. This really wasn’t a surprise, as we experienced similar findings from testing we did after the 2018 Woolsey fire in Malibu. There are relatively high, naturally-occurring levels of arsenic present in soil throughout the Santa Monica mountains and nearby areas. Even California’s Department of Toxic Substances Control (DTSC) recognizes this. DTSC considers the threshold of 0.07 ppm for contamination, but they allow up to 7.0 ppm in the local area. I’m certain a good deal of the arsenic we found was due to topsoil getting blown around during the fires thanks to the 100 mph winds and heat.
• There are reports of other metals of concern appearing, such as barium, chromium, cobalt, and beryllium. We have occasionally seen low levels of these metals indoors, and in a few rare cases the levels were over what the DTSC considers to be contamination for soil. The DTSC permissible soil levels have been widely used as a guideline for indoor contamination, because there really aren’t other great standards in some cases.  Of these metals, I find beryllium the oddest to show up, as it is not a common metal to be used in construction or manufacturing.
• While people were scared about lithium contamination from electric car batteries, we have not seen much of it showing up in samples either indoors or outdoors. Lithium is not on the DTSC’s list of toxic heavy metals. It is not considered highly toxic, so even when present,  it does not appear to be much of a worry.
• On the asbestos front, we have not really found any homes significantly contaminated with asbestos.  We have only seen samples from two different homes come back with trace levels. This includes asbestos wipes by TEM (Transmission Electron Microscopy) analysis, the more sensitive of lab analysis methods. We initially used PLM (Polarized Light Microscopy) analysis on asbestos wipe samples, based on recommendations from two labs and Certified Asbestos Consultants. PLM is much less expensive and simpler to deal with than TEM samples. I still think PLM is a better choice than TEM, and we’ve seen similar results with both lab methods.  We have not had a single air sample detecting any airborne asbestos. This, in my opinion, is the most important test for asbestos, as it is an airborne hazard.
• In regard to Volatile Organic Compounds (VOCs), we have not seen anything of note. We have many years of experience with VOC sampling utilizing the EPA TO-15 method, which is the gold standard for VOC analysis. There are always some VOCs present in everyone’s home and also outdoor ambient air. With the fires, we took our first VOC samples (in the Palisades) about three weeks after the fires. We found nothing interesting, just the kinds of things you normally expect to see. In the entire time since, that’s been the story, both pre- and post-remediation. We did have one home in the Eaton area that had samples come back with some benzene, but the outdoor level was actually quite a bit higher, so the indoors was not the source of the benzene. None of these findings are really that surprising, because these chemicals readily evaporate at room temperature, hence the word volatile in their name. Even if they do get inside people’s homes, they are not going to be hanging around for a prolonged period, and certainly won’t be present in significant amounts months after the fires occurred.
• Polycyclic Aromatic Hydrocarbons (PAHs) have been another contaminant that has turned out to be not a worry. We have not detected them at all. In some cases, we directly sampled the debris piles and still got nothing. I would expect this to be more of an issue when a fire occurs inside a property, and not from exposure to wildfire smoke.
• Cyanide is something that has come up as an issue, primarily driven by a company that has been telling people that they have cyanide in their wallboard, and therefore it should all be ripped out. Even if cyanide was in drywall, it is not the same thing as being exposed to it through the air, which is the route of exposure of concern.  In fact, we have done testing for airborne cyanide in many homes and have consistently not detected anything, down to the microgram level. Hydrogen cyanide boils at 78 degrees F, so this is another chemical that is very unlikely to be present long after the fire. I suspect that some of the homes that had wallboard test positive for cyanide might have had some already there before the wildfires.

So that is it. And based on these findings, we’ve provided recommendations on what’s most important for post-remediation testing.  It’s a pragmatic guide to what you really need to do after remediation.  You can read more about it in my accompanying article here. 

If you have any further questions about your specific situation, or would like to discuss how we can help you with post-remediation testing, please reach out to us. We are here to help!