The Eaton Fire Hit Caltech Scientists Close to Home. Now, They’re Studying the Toxic Aftermath

As a geochemistry professor at Caltech in Pasadena, Francois Tissot normally spends his time studying rocks formed at the beginning of the universe. But ever since wildfires tore through Los Angeles in January, burning thousands of homes, the Big Bang has taken a back seat in the professor’s life.

Tissot, an Altadena resident, has dedicated much of his lab’s resources to studying the toxic aftermath of the Eaton fire. He’s spent the last few months testing the ash that blanketed surviving homes for harmful contaminants like lead, cadmium, and arsenic.

“We have all the equipment. We have all the expertise. We’re right there,” Tissot said. “If we didn’t do it, it would be criminal.”

A team of graduate students, led by Tissot, has visited the homes of over 50 people who volunteered to have their properties tested. The scientists swab surfaces with wet wipes and bring samples back to the lab for analysis. All the work is done in an ultra-clean room to ensure accuracy. It even requires a uniform: lab coat, hairnet and Crocs.

Dust from each sample gets dissolved in a vial and sucked up through a machine called a mass spectrometer, which spits out data on a spreadsheet. The results are a wake-up call.

“The answer is there’s a lot of lead everywhere,” Tissot said.

Inside more than half of the homes tested, lead was detected at levels over the limits set by the Environmental Protection Agency. One home even had 30 times the limit. According to the Centers for Disease Control, there’s no safe level of lead exposure for children, and even small amounts can directly hinder children’s brain development.

The results from Caltech’s study are personally disturbing for Tissot—his own home was one of the first tested by the lab. It survived the fire, while the rest of his block was leveled. Since January, Francois has thrown himself into this project and is treating his house like any other testing site.

“Being in the house without having to do anything is so depressing,” Tissot said. “This project gives a sense of purpose.”

Contamination close to home

Tissot and his family have lived in faculty housing near campus since they evacuated during the Eaton fire in January. Outside his house in Altadena, Christmas lights are still up, and there’s a rotting box of subscription produce on the doorstep. It was eerily quiet as we drove down his empty street in March.

“It’s like two parallel worlds,” Tissots said, taking in the sight of his mid-century home. “I can remember exactly how it used to look and everything. Every time I visit, it’s like overprinting a nice memory with an image of devastation.”

At first glance, the house seemed okay, but closer inspection revealed the extent of the damage. What used to be astroturf is now a bubbly black puddle of plastic. The walls of the house cracked, plastic window frames melted, and the roof got so hot it dripped molten tar into the attic.

“So clearly the house has sustained a very intense thermal event. It went through hell,” Tissot said.

To add insult to injury, the place has been looted. But that’s actually the least of Tissot’s problems because, based on the tests conducted in his lab, the house is chemically compromised. Every room contains lead that is over the EPA limit. His youngest daughter’s room is especially bad.

“There is no cleaning her stuffed animals. There is no getting her clothes back,” Tissot said. “That room is completely contaminated.”

On top of the lead testing project and his usual geochemistry research, Francois is spending almost every day on the phone with his home insurance, struggling to get professional remediation services and follow-up lead testing covered. He’s been told that once cleaning is complete, it means the house is clean—no follow-up testing necessary.

“As a scientist, that’s not sufficient,” Tissot said. “I’m not going to put my kids back in a house that they haven’t demonstrated is fully clean.”

Despite the ongoing frustration with his insurance, Tissot is committed to staying in Altadena, the place he’s called home for the last six years. He was drawn to the area because it reminded him of the French countryside where he grew up.

“You get bobcats and coyotes. There’s something very primal to being connected to nature that way, which I greatly enjoy,” he said.

If his home isn’t proven to be lead-free, Tissot said he is willing to demolish and rebuild.

The results are in

The map of homes tested by Caltech is a collection of red, orange, and yellow squares, representing homes with elevated levels of lead, and green squares, with minimal levels of the element.

Stephanie Chan’s house in Glendale — a 20-minute drive from the burn scar in Altadena — is an orange square. She has a four-year-old daughter and isn’t thrilled by the results, which indicated high levels of lead are present all over the house.

“I’m more worried because I thought everything was okay,” Chan said. “But there hasn’t been any kind of guidance.”

Tissot met up with Chan to talk through the best course of action. According to the professor, because the extent of lead detected inside is less than in some other houses — and, under the EPA limit — Chan may be able to clean surfaces with a wet wipe rather than pay for professional remediation.

But, Tissot admits, administering this kind of advice is outside of his expertise. So, he’s sharing his testing with Pasadena and L.A. County Departments of Public Health so they can issue official recommendations for addressing this invisible chemical danger.

In response to Caltech’s results, a spokesperson for the City of Pasadena shared a statement:

“These independent data collection efforts offer important pieces of the puzzle, valuable to the overall assessment of environmental conditions in Pasadena and throughout the region. We are tracking these studies closely and issuing relevant public health guidance when needed.”

They linked to a guide on “Returning Home After a Fire” and recommend that homeowners consult a remediation professional to determine individualized guidance. The L.A. County Department of Public Health directs residents to their own post-wildfire safety guide.

Altadena residents are mapping a “Toxic Soup”

Scientists aren’t the only ones keeping tabs on lead in the community. A coalition of Altadena residents called Eaton Fire Residents United (EFRU) has published their own map visualizing the results of commercially conducted contaminant tests, some paid for by people’s insurance.

Altadena resident and data scientist Nicole Maccalla developed the map. She’s collaborating with Tissot to incorporate Caltech’s data and highlight the common theme between their findings.

“The story is there is widespread contamination, and it goes well beyond the burn zone, way further than just Pasadena,” Maccalla said. “I don’t think the public knows that.”

Every day, new residents are emailing EFRU to share their own testing results for the map. That’s keeping Maccalla busy, on top of dealing with her own house in Altadena, which is currently unliveable, a situation shared by many members of the group.

“I’m behind on everything in life right now,” Maccalla said. “We’re all juggling multiple things, plus trying to take care of our displaced families.”

She’s proud of the community engagement represented by the project but is disappointed in what she feels is a lack of government response.

“This is not our day job,” Maccalla said. “I think it’s ridiculous that it’s not the public health department or the county or the state or insurance companies sharing information.”

Maccalla would like to see public health officials going door-to-door to ensure everyone is safe from toxic chemicals, including lead as well as other hazards, like asbestos. According to Maccalla, elders and non-English speakers are particularly vulnerable.

“Not everybody even knows you need to clean or what cleaning entails. We won’t know if cleaning works unless we test,” Maccalla said. “Why is this on individual residents? Why are we going to let our community sit under a toxic soup?”

The EFRU map is set to be updated on a weekly basis as more results come in.

Caltech received over 400 requests from volunteers hoping to have their properties tested by the school. Tissot is still fielding regular emails from people asking for his help. While the Caltech study is at capacity, other universities, including USC, are also collecting contamination samples. The L.A. County Department of Public Health is publishing the results from these institutions’ efforts.

At some point, Tissot’s team plans to retest the same 50 homes included in his study – once debris removal is complete – to track the extent of contamination over time. He’s prepared to spend the next several years studying and publicizing the results, no matter how uncomfortable they may be.

“Science is forcing yourself to always reevaluate what you think you know,” Tissot said. “I hope the data that we produce will be looked at very closely by the city, the state, and the appropriate response will be built from that.”