After the Flames: Understanding Combustible Byproducts and CBP Testing

The flames are out, the smell fades, and the walls look “clean” again but what if the real danger is still there? We talk through the hidden side of smoke damage: combustible byproducts left behind after a fire, including soot, ash, and char, and why those fine particles can pose serious indoor air quality and health risks when they settle across a property.

We walk you through CBP testing in plain language, including why a simple wipe test can reveal what the naked eye misses, how lab analysis separates soot vs ash vs char, and what a rough “normal background” threshold can look like when you are trying to understand results. Along the way, we share some of the strangest fire aftermath clues, like web-like residue from burned plastics that gets mistaken for spider webs, and why different fuel sources such as protein fires, plastics, and wood can change the contamination profile. 

We also get practical about what happens next: how smoke can migrate through HVAC systems and shared building spaces, why a “not affected” room or suite may still test positive, and how this data can guide decisions on cleaning, encapsulating, retexturing, replacing materials, or tossing items like certain electronics. We close with the real-world reasons testing timelines vary, from insurance adjusters to fire investigations, and why post fire environmental testing helps you stop guessing and start documenting. Subscribe, share this with a property owner who needs it, and leave a review with your biggest question about smoke residue and remediation.

To learn more about DCG Environmental visit:
https://www.DCGEnvironmental.com
DCG Environmental 
Serving Property Owners in Dallas, Houston, and Austin 
972-876-0008 

Transcript

Welcome And What We Test

SPEAKER_00 0:04

Welcome to the Environmental Testing Show because what you can't speak to Add of Fector Help. Hosted by Shelly Hyde, CEO of DCG Environmental. This episode explores the hidden environmental hazards of impact homes and commercial spaces. From molding expected to other unseen residents, serving property owners throughout Dallas Houston and Austin. DCG Environmental believes finding the problem is the first step to making everyone safe.

SPEAKER_02 0:41

When a fire occurs, the damage you see is only part of the story. The real risks often hide in the residue left behind, and knowing how to test for them can protect both property and health.

What Combustible Byproducts Are

SPEAKER_02 0:52

Welcome. I'm Julie Schwenzer, co-host and producer with Shelly Hines, the CEO of DCG Environmental. Shelly, it's great to chat with you and learn from you. So this is a topic many property owners might not even know exists until they're dealing with a fire. Could you please explain what combustible byproducts actually are?

SPEAKER_01 1:14

Yeah, the combustible byproducts are the residues left after a fire happens. So we specifically test for soot, ash, and char. And these are the ones that we're finding are carcinogenic. So they cause health problems when left in big enough quantities. People breathe it in.

Strange Fire Clues You Miss

SPEAKER_01 1:34

Fire is fascinating. Like as devastating as it is, it's really I don't want to say awesome because it just sounds wrong to say, but it's really interesting to see what happens after a fire. How ceiling fans melt and just hang downward, how a wall can be completely black, but if you take the picture off the wall behind the picture, it is solid white or whatever color was behind it. It's really unique in the way that it burns different materials. We've actually seen what we would think would be spider webs, but they're not. It's actually polymers and plastics that have been burnt and then leave like spider web-looking webs, and a lot of times it's mistaken for spider webs. So there's a lot to learn about fire. We love uh doing the testing sometimes, sometimes you can't see it, right? Soot is very fine and it clings to everything. And so what appears by the naked eye is clean, sometimes is not. And that's where this kind of testing comes in to help identify how far the fire went or how far the byproducts of the fire went. So it matters and depends upon what burnt. Protein fires, so a lot of times when we see kitchen fires and meats are burning, those are some of the more dangerous ones, ironically. Um, obviously, if plastics burn, that puts a lot of chemicals into the air. Wood burning is one of the most normal fires, obviously, because that's what we use in fireplaces, but uh the soot, ash, and char that it can leave behind if it's not enclosed in a fireplace or not, you know, where the smoke goes up the smokestack. This is why you have to get your fireplace cleaned, uh, usually recommended once a year, so that all those soots get cleaned out of the pipe that goes up the up and out of the house to carry all those smoke debris

How Wipe Testing Works

SPEAKER_01 3:27

out. Um, but the the testing is pretty easy. It's uh it's considered a wipe test. You can do air and you can do a tape lift. Um, the one that we're that we see the most success with is a wipe because it actually captures the particles. So then it goes to a lab and then it's um put underneath a microscope, and then they identify how much is soot, how much is ash, and how much is char. Char is the bigger pieces, um kind of like charred wood. If you'd see uh rafters burnt after a fire, they look very um like bark-like, if you will, but all black, of course, because of the fire. And then soot, I mean char is the things that'll float in the air. So if you've ever been to a bonfire and see the little pieces floating in the air, that's more like what uh so uh uh ash is. And then soot is the fine, fine particles. Those are the things that you can't see, but if you wipe the table, your fingers come up black.

What Results Mean And Thresholds

SPEAKER_01 4:23

So um there's still a lot of studies, there's not a lot of regulation yet in environmental industries to say how much is too much. Usually what we see or what has been determined as a normal practice is if it's less than 3% when the results come back, that could be caused by a candle in the house, it could be caused by environmental um exhaust from cars, something burning outside. When you've had a fire, um, let's say there's a fire in the kitchen, uh, we can test each room to see if that smoke had traveled all the way back to the master bedroom or whatever room happens to be the farthest away from where the fire started. Same thing in a commercial building. We had one instance where it was a strip

Proving Smoke Spread In Buildings

SPEAKER_01 5:12

mall, and I think there was four or five units, so they are all in a row. The unit on the end is the one that had the fire, and the adjuster was trying to say that this one was not affected because he couldn't see anything. But what they didn't know is there was an open plenum at the top that went across all four, and so the smoke had gone from the far end up into the plenum, and then as your HVAC system pushes it back down into the area, it pulls air from that plenum. So that unit was affected, but we were only able to prove it by doing the CVP testing, the combustible byproduct testing. So a lot of times it can really help identify what was affected, what needs to be cleaned, what needs to be thrown away. Some electronics can't be saved, some of those have to be thrown away. So it just depends on what burnt, how long it's burnt, um, how it was put out, because a lot of the chemicals that are in fire retardants also have to be cleaned up. So there's a lot to it with a fire, and it's really, really interesting to see depending upon what burns.

Why There Are No Standards Yet

SPEAKER_02 6:13

And what are some things that first-time property owners may need to understand about byproducts and the CBP testing? And is there a big difference between residential and commercial?

SPEAKER_01 6:27

No difference between residential and commercial. It's not regulated in our industry yet. Um there are some classes that we can take. There are some IICRC methods on how to clean up after a fire, but there are no standards yet on how much is too much. No rules or regulations yet. Nothing determining how much is too much that affects somebody or how much would cause you cancer, how much would not. Um, and it's kind of fairly newer in the industry as far as uh determining you know, when do we gut the place or when do we just clean it? And that would depend on what burnt there are. Like how did the smoke migrate throughout the house? Did it get into the HVAC system? Was the HVAC system running? Did it continue to run after the fire to where it distributes the smoke throughout the house? Um, did it happen in the garage? We see a lot of garage fires, uh, golf carts. Uh I had a beautifully new restored car catch on fire. I was heartbroken. Yeah, that is just gotten a restored. It was, I can't remember the type of car, but I just remember going, wow, that's rare, and it probably was beautiful. Um there's residues that are left, right? So there's dry carbons, um, melted synthetics, uh sometimes conductive

Cleanup Options For Different Materials

SPEAKER_01 7:49

or uh uh corrosive residues can be possible depending upon what burn. So there's a lot of different types of cleaning methods that are usually regulated by IICRC. I won't say regulated, but it's that's that's what the remediation companies go by. Those are the rules on how to clean up things like this. So sometimes they don't know that it's there or that it went that far because if it's just soot, it's hard to see sometimes. Um we do a lot of testing in the HVAC system. How do we get that out of there? Can we get it out of there? Does it need to be replaced? Um, walls usually can be cleaned and then repainted or encapsulated first and then painted. So there's different products, different materials that depend upon how much is there, would depend on how it's cleaned or remediated back to pre-status before it was burnt. They do a lot of um HEPA and vacuum cleaning and using chemical sponges, and that gets a lot of the residue. Um, sometimes they have to use a degreasing or an odor counteragent wash. Um they can do sometimes, like a ceiling needs to be scraped and retextured. You can't get all the soot out of those if you have a um a popcorn ceiling, if you will. There's a lot of nooks and crannies in there that you can't get the stuff out, so sometimes they'll scrape off that texture and then retexture and repaint. So it just depends on what was burnt and how damaged it was. We see a lot of kitchen cabinets, if it's uh melanine cabinets, usually the water from the fire department just melts those. It doesn't melt it, but it it soaks up a lot of water. And um, if it's a good wood solid cabinet, then sometimes those can be refinished and re-re-cleaned. So it just depends on what the material is, what it was made of, and how it was affected. So it's it's there's no one-stop shop. You don't just come in and say, This is what we do for everything. It's very um pointed towards what burnt, what was in the air, and how did it get dispersed.

When Testing Can Actually Happen

SPEAKER_02 9:45

How soon after a fire occurs do you and your team get in there?

SPEAKER_01 9:49

That depends on um a lot of factors. It can depend on how long does it take to the adjuster, to insurance adjuster to come out and um deem that it needs to be tested. Uh it could be depends on the fire department if it's uh being investigated. You know, what caused the fire? How did it start? Especially in commercial buildings, a lot of times, you know, was it arson? Was it an accident? Was it electrical? Um residents, the same way. Sometimes if they're not sure how it started, you can't get into the home until that's been deemed because we can we can um contaminate the investigation. So there I don't have a good answer for that. It could be weeks, it could be months. It just depends on how fast all the rest of the process goes. A lot of times, you know, the fire department's called first to put out the fire, and then remediation companies are contacted to come clean up, but in that process, you have to wait on the adjuster to approve everything. Like they may come give an estimate, they may they may argue. Um, no, you don't need to go that far. And then sometimes we're called in to prove that it did go that far, or that it did go out throughout the house, or how far did it go throughout the house? So sometimes it's an automatic, so it just depends on your insurance company, what kind of coverage you have, and what remediation company you're working with. Some remediation companies just go in and clean and no big deal, and everybody's on the same page and it all gets cleaned. And then sometimes it's like, hey, we're not sure, you know, we really need to figure out how far this goes. So again, it's case by case basis, depending upon what burnt and how long it burned and how long it took them to put it out.

SPEAKER_02 11:22

Well, Shelly, thank you so much for breaking this down. Um, this topic can feel overwhelming for property owners, and you broke it down clearly as usual. So thank you.

SPEAKER_01 11:31

You're welcome.

Final Takeaways And How To Book

SPEAKER_00 11:36

Thanks for listening to the Environmental Testing Show. If you're concerned about mold, asbestos, or other environmental hazards, peace of mind starts with proper testing. Call 972-876-0008 or visit dcenvironmental.com to schedule a convenient appointment. Because when it comes to your environment, guessing it's the safety plan.