Tracking The Toxic Fallout Of The LA Fires

An urban fire can release all kinds of chemicals. One year after fires hit Los Angeles, scientists are trying to understand the toxic fallout.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:14Ira Flatow?

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• 0:34Flora Lichtman?

  Hey, it's Flora Lichtman, and this is Science Friday. Today in the show, the toxic fallout of urban fires. This time last year, Los Angeles was on fire. More than 16,000 homes and buildings burned to the ground. Cars, batteries, solar panels, insulation, cleaning supplies, all up in flames, releasing toxic chemicals into giant smoke plumes that wafted across the city. A year later, scientists are trying to understand the fallout from this urban wildfire. What chemicals were left behind? How to remediate them? And what threats they pose to our health? My next two guests have been at the forefront of this research.

• 1:17Flora Lichtman?

  And for one of them, this work is personal. Dr. Francois Tissot is a geochemist at Caltech, and Dr. Yi Fengzhu studies air quality and its health effects at UCLA. Welcome to both to Science Friday.

• 1:29Speaker 03

  Thank you for having me.

• 1:31Speaker 04

  Thank you.

• 1:32Flora Lichtman?

  I want to get into the toxicology in a second. But Francois, let's start with your personal story. What happened in your neighborhood?

• 1:39Speaker 04

  Yes, well, our neighborhood was almost completely burnt down. Our streets, only the house that we used to live in and another one didn't burn. Everything around is just complete desolation. The house is so contaminated with heavy metals and asbestos, and it's completely unlivable and unsafe.

• 2:00Flora Lichtman?

  Hmm, I mean, obviously, this is so personal, but you also made it professional. Why?

• 2:07Speaker 04

  Well, we made it professional because we have the tools to make a difference and bring data that was missing. I guess the first thing I did when I saw that the fire was happening is I looked up if there was any paper that we're discussing. How much lead and heavy metals and contaminants will be transported and how far and how, what are the risks? I wanted to understand, but it turns out there is almost no literature on this kind of urban mega fires. There are new kind of threats. There is very little that is being known. And there was nothing for me to make an assessment of risk um from. So I told my group that if anyone in the group wanted to work on this, we should really do it. And the response was very positive from them.

• 2:50Speaker 04

  And we we got started immediately trying to answer very basic questions such as the lead that had been seen in the air. How far did it go? How much was released? How how much of a danger to human health is it?

• 3:06Flora Lichtman?

  What do you usually work on?

• 3:07Speaker 04

  Uh my training is in a field called cosmochemistry and geochemistry, which is the study of planetary formation and solar system evolution using meteorites and chemical tools. Um typically, we make very complex isotope measurements, very precise measurements. Concentration measurements are much simpler for us. They're usually the step one of anything we do. And except in this case for the fire, concentrations are all you need to know because you just wanna know if the element is present in what quantity so that you can assess how big of a risk it is.

• 3:45Flora Lichtman?

  Uh I mean, you must have felt desperate in some way to get these answers.

• 3:50Speaker 04

  I was really shocked to see that there had been no systematic studies until now because urban fires are not a complete novelty, but I I guess the the magnitude and the scale of the devastation that those mega fires um bring, this is novel. It has not been studied. And so.

• 4:11Speaker 04

  Well, I guess we were at the wrong place at the right time to make a difference.

• 4:16Flora Lichtman?

  Yifan, I know you have been collecting samples and testing the air for the last year. What have you found?

• 4:23Speaker 03

  Yeah, so we took three phases of measurements, right? We collected air samples during active fire period. And then went back again and take measurements when the fire was about halfway contained. And then, you know, went out again, another round to take air samples when the fire were completely put off. So when we take measurements, we collect samples inside and outside people's home, both indoors and outdoors. I think the big surprise to us is how much higher some of those chemicals were inside homes comparing to outside after the fires were over.

• 5:04Speaker 03

  So this is especially true in homes where no one was living at the time, right? So we, we know, you know, there's lots of indoor sources, cleaning products, cooking, smoking all can produce those releases inside people's home. But the fact that we're seeing those high levels inside homes that is unoccupied really tells us there's some source going on in those homes. So this is a really, you know, important public health message, basically, like, you know, saying that people really needs to be aware about potential exposure and risk when they considering returning homes, right?

• 5:39Flora Lichtman?

  When you say inside, was it air quality? Was it, you know, your sofa was loaded with these toxic chemicals? What do you mean?

• 5:46Speaker 03

  Yeah, that, that's a very good question. We actually did like two parallel projects where we're actually studying off-gassing from soft goods, household materials like carpets and clothing, stuffed animals, pillows. Those soft materials, they get soaked by the fire smoke during the active fire period. And then, you know, after the fire is over, they were kept inside people's home. And for security reasons or people just worry about, you know, outdoor air quality, oftentimes they just kept their home sealed. So those, those soaked materials, they will start to off-gassing, basically giving back those chemicals into the indoor space.

• 6:30Speaker 03

  Because the indoor space is now well-ventilated, so they just get accumulated inside people's home.

• 6:37Flora Lichtman?

  So like your rug or your couch absorbed all of these chemicals and then is just basically off gassing them?

• 6:45Speaker 03

  Exactly.

• 6:46Flora Lichtman?

  Francois, did you test your, did you sample inside your own home and what did you find?

• 6:51Speaker 04

  Yeah, my house was one of the first homes that we, that we sampled, of course. We found what we find in any home in the burn area. Elevated lead levels above the recommended safety limits from the EPA. We found very high levels of arsenic as well. Both of which are coming from the constructions that burned around our house. For different reasons, lead was in lead paint and in lead pipes. And the houses in Altadena were all very old, most of them were built before the 1950s. So before any ban on lead or asbestos.

• 7:33Speaker 04

  And the arsenic was used as a termite treatment for, until the 2000s. And so all the wood from all the houses around us was containing this arsenic and it released it when the house is burnt.

• 7:47Flora Lichtman?

  Are, are people having to pay for testing for these chemicals themselves?

• 7:52Speaker 04

  It is one of the main problems that the local community is facing. It's that insurance companies, they have a guidebook that they follow on what to do after a fire. But their guidebook is based on wildfires. And wildfires do not release arsenic or lead or any of those toxic elements because it's not in trees or the shrub or anything like this. So when, when I asked for testing in my house, because I had already tested and I already shown that there was lead and arsenic and all of these elements. Their response was, we typically don't do this testing, so we're not covering for that cost. And also, there is no reason there should be lead in your house. My response was, of course, well, I have already measured that there is lead.

• 8:37Speaker 04

  And they said, well, you're not a credited lab, so we will, we'll have to have a professional lab tests, test your house. And when I asked if they'd do it, they said, well, we, we don't do it in this instance. So then there was this catch 22 where- It is there, I showed it's there. But their guidebook does not say to do this testing unless there is a reason to think that there is lead, uh, which just me saying it was not enough for them.

• 9:04Flora Lichtman?

  Right, and they don't think that there's lead because there's no actual scientific research, there's not a lot of scientific research showing where you might find lead after an urban wildfire because it's a new kind of disaster.

• 9:15Speaker 04

  It's, it's, uh, and, and this is something the National Academy has said wildfires at the urban interface need to be studies, studied because we don't know the risk. And, but it has not come to, come to reality yet.

• 9:31Speaker 03

  Yeah, I mean, there's a like a wide range of, of contaminants, right? From organics to heavy metals, arsenic, there's also benzene, toluene, they're all like say have, uh, serious house effects and insurance company, they're, they're not obligated to test those, uh, chemicals at all because some of those, you know, they're not like have clear health standards, um, published by, or enforced by the government. So, so there are really limited testing going on in those, um, homes, so during this post of fire recovery period and, and we know, um, there, they have house effects when people exposed to them for a long time.

• 10:09Speaker 04

  This is also why we started this work because it is very needed for the next fire and there will be one such next fire because right now, one in three houses in the U S is in an environment that's called the WUI, the Wildland Urban Interface. This is where most of the expansion of the cities have happened and those are the places where very tightly packed houses interspaced with brush and other fuel can basically burn like Eltadinha did.

• 10:40Flora Lichtman?

  We have to take a break, but don't go away because when we come back, we're going to talk about where we go from here. Stay with us.

• 10:57Speaker 00

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• 12:07Flora Lichtman?

  Okay, we're back. Yvonne, can these toxic chemicals that we're talking about, you know, we're talking about asbestos and lead and benzene and others, can they be cleaned up from a house?

• 12:18Speaker 03

  Yeah, that's a big question. It's just like Frank mentioned, we realized that there were, you know, how little knowledge that is out there in the scientific community, let alone guidance and postfire remediation and all those uncertainties, I feel, especially for vulnerable communities, is really challenging. So, so there are some insights, like general guidance, I think we feel comfortable to give to homeowners and residents. Like, we know that, for example, on the air side, we know, like, increased ventilation in your indoor space could help, running a heap air purifiers, especially with charcoal filters could help reduce volatile organic compounds.

• 13:02Speaker 03

  Remove particles, we suspended from deposit dust. Um, you know, cleaning up your HVAC system is really important. Doing remediations, remove those um, smoke impacted uh, soft materials from the indoor spaces, all of those could help. Uh, but you know, we really don't have in enough data to give uh, concrete answers about which method is the most effective or cost effective at this point.

• 13:30Flora Lichtman?

  I mean, Francois, will you feel safe going back to your home?

• 13:34Speaker 04

  Uh, that's a very good question. Um, every expert that we have brought into our house, which has suffered extensive smoke damage and led and asbestos contamination, has said, you have basically two options. You can either demolition rebuild and that will remove the contaminant, of course. Or you can strip down the house to the studs and then rebuild from there. And the rationale for them is they do not know that they can clean the house by just cleaning the surfaces. The only way that they can envision cleaning is removing the contaminant, removing all the porous materials, including the walls. And anything that was inside the walls. And that goes back to your question of can we clean?

• 14:19Speaker 04

  And it's, it's an open question. When the amount of contamination is low, maybe a couple of times above the EPA limit. Yes, cleaning is possible. You can use wet wiping techniques and hepa vacuuming and remediation companies know how to deal with that level of contamination. What this particular fire has brought to light is that some houses have been contaminated to such an extent that we do not know if the cleaning techniques that we have are appropriate or efficient at all. And, and until research is done to answer this question, then the only, only approach is to remove the material itself.

• 14:59Flora Lichtman?

  I mean, Yifeng, how long will it take to know the health impacts from this fire?

• 15:04Speaker 03

  Yeah, so there's, you know, acute health effects. There's already studies being published like showing during the active fire period, the number of ER visit went up. Not only the number of ER visit went up, it's also the abnormal blood test from those ER visit went up like relative to the previous year of the same sort of January timeframe. So the acute health effects is already being, you know, showing up and documented. The long-term health effects from those wildfires is really a big gap, knowledge gap.

• 15:39Flora Lichtman?

  Has there been any federal support for tackling some of those unknowns?

• 15:45Speaker 03

  So I have an opinion that you just grasped and it's been pending for a month. So it's supposed to be a rapid, rapid grant mechanism, but clearly not so rapid. So the funding climate at the federal agency levels is definitely also not helpful in this setting.

• 16:06Speaker 04

  Yeah, I guess I can jump in here. The climate of funding is really making it difficult to go after those kind of questions. The only reason that we've been fortunate enough at Caltech to do it is because Caltech was supporting this research from a few days after the fire. They immediately said, whatever you guys need to do that can benefit the community, do it and we will find the money for it.

• 16:29Speaker 04

  This is what federal agencies should do. This is what those rapid proposals that Yifeng was referring to should be doing. Clearly, this is not the priority right now.

• 16:40Flora Lichtman?

  Francois, your usual research is on, you know, as you were saying, the solar system and how planets formed. What's it like to go from studying something, you know, wondrous and abstract to is my house going to poison me? Like, has it changed the way that you think about science or your own research?

• 16:59Speaker 04

  It's definitely a different exercise.

• 17:04Speaker 04

  There is a sense of responsibility that comes with it that I'm very aware of and I'm immensely proud of the work that my group has been doing trying to address such a difficult situation. If this data had existed before, it would have made everyone's life, myself included, so much easier. We wouldn't have to argue for months or years on end with insurance. We would It would just, yeah, it would just have made it easier to face an already extreme challenge.

• 17:38Speaker 04

  If we, and by we, I mean my group and other researchers, can bring answers that will prevent some further suffering in future fires, then it will be worth it.

• 17:52Flora Lichtman?

  Dr. Yi Fengzhu studies air quality and its health effects at UCLA, and Dr. Francois Tissot is a geochemist at Caltech. Thank you both for joining me today.

• 18:01Speaker 04

  Thank you so much for having us.

• 18:03Speaker 03

  Thank you.

• 18:05Flora Lichtman?

  This episode was produced by Rasha Ariedi, and y'all, Russia needs your help. I'm about to pivot, so that's your warning. We are working on a show about games and gamification, and we want to hear from you. Tell us about a time when a game changed your life. There's lots of different ways this could go. Maybe it's that first time you closed the ring on your Apple Watch and you turned into an exercise freak for life. Or maybe it was something more analog, like a game of Truth or Dare when you were a tween that you'll never, ever recover from. Tell us a story about how a game changed you, for better or worse. Please leave us a voicemail, 8774-CY-FRI. That's 8774-CY-FRI. Thanks for listening. Have a great weekend. I'm Floran Lichtman.