In the weeks after the Palisades and Eaton fires, the Dornsife Public Exchange team met in the Earth Sciences building, looking for a way they could help people affected by the fires. That’s when Josh West walked in. 

The professor of earth sciences and environmental studies had lost his own home to the fires and had been testing the soil in his neighborhood. He brought Public Exchange an idea: What if they could expand West’s project to provide free soil testing to all Angelenos affected by the fires? 

From that meeting, Contaminant Level Evaluation and Analysis for Neighborhoods, or CLEAN, was created to bring Los Angeles residents rapid-fire soil testing so they could know whether their homes, schools, parks or communities had harmful contaminants. 

“The CLEAN effort really came about from a group of faculty and students, and the group at Dornsife Public Exchange, all realizing in the aftermath of the fires, not only how tragic the fires themselves had been, but how challenging they were going to be for residents in L.A.,” West said.

Since starting in 2025, CLEAN has tested over 6,000 soil samples across L.A. at no cost to participating residents. And last month, they used the program to respond to the Boyle Heights warehouse fire, providing rapid soil testing to residents near the facility.

When CLEAN was founded, there was no government-led soil testing project available. That led West to come up with the idea for CLEAN so he could help families deal with long-term environmental consequences that, at the time, didn’t have an easy or cheap way to be identified. CLEAN’s main focus is lead testing due to the substance’s pervasiveness in L.A. County.

“The scale of these fires meant that government resources were really stretched thin,” West said. “The response from federal, state and local government authorities was never going to be up to the full task of assessing and getting people informed about what had happened.”

USC already had the equipment to test for lead, and Public Exchange, a program that puts USC research into service-based, real-world projects, realized it could use that equipment to quickly give residents soil contamination results.

Cat Odendahl, a fifth-year doctoral student studying ocean sciences, manages CLEAN’s lab. She first got involved in looking at the soil samples as a class project, but when it kicked off as a county-wide community service project, she was asked to take CLEAN on as one of her doctoral projects. 

“I was looking for some avenue to use the science that I’m really comfortable with to help the community in some way, and then we spun it from there … [and] hit the ground running, like, ‘Let’s create this community sampling scheme,’” Odendahl said.

Although CLEAN has primarily been focused on certain areas affected by fires, there are drop boxes across the county — all Angelenos are eligible to drop their soil for CLEAN to test.

Max Teirstein, CLEAN’s project manager, said all South Central residents should take advantage of CLEAN; even if they may not be worried about wildfire contamination, they can learn if there’s lead or any other harmful contaminants in their soil.

Some ways people have used the program, he said, are to know if it’s safe to plant fruits and vegetables in their yards, or if young kids may be ingesting toxic soil. 

Lead is a major contaminant in L.A. County that existed long before the fires made it more concentrated, West said.

A map of CLEAN drop box locations can be viewed online. Anyone who doesn’t have a drop box near them can bring their soil to the county office, which will direct those inquiries directly to CLEAN.

Since Eaton, CLEAN hasn’t stopped. The program recently responded to the Boyle Heights warehouse fire in June by focusing outreach efforts there, Teirstein said. 

Shortly after the fire went out, they collected their own samples and saw an uptick in samples submitted in their drop boxes in the area.

“Wherever there’s a fire in L.A., we want to be there and help provide our service to people in the area,” Teirstein said.

They’ve come a long way from when they started, Teirstein said.

“At first … we could barely keep up with the demand,” Teirstein said. “A year and a half in, [we’ve] received over 6000 samples, but probably about half of those came in the first month to six weeks.”

Teirstein said fire victims were in need of a cheap way to know if their yards were contaminated, and that’s where CLEAN stepped in.

The most meaningful part of the project for West is the overwhelmingly positive feedback he’s received from community members. He said CLEAN has helped remove an element of uncertainty from the rebuilding process. 

“In the months immediately after the fire, there was just so much information and guidance being thrown at them from lots of different sources, that it was really helpful to have a guide that could help them discern what information was relevant to them and what wasn’t,” West said. 

According to Odendahl, the CLEAN team even received notes in some of the samples they got, which they hung up. She said these serve as a good reminder of how CLEAN is helping the L.A. community through their work.

“This isn’t just dirt that we’re processing for no reason,” Odendahl said. “This is somebody’s soil, somebody’s house burned down, and they’re trying to rebuild.”

According to Odendahl, CLEAN is “community-driven,” meaning 100% of the samples they collect are sent in through the drop boxes across the county. The samples are collected from the drop boxes by the lab team about once a week and brought back to the lab, where they are cataloged by the lab workers.

After filtering out large rocks, the team dries a quarter-sized sample overnight and puts it through the analyzer. The analysis takes 15 seconds, and the team gets a reliable lead measurement. Results are available to view online within four to six weeks, according to their website. 

As the lab manager, Odendahl oversees a team of undergraduate students who work on the project. She said students who are interested in getting involved in CLEAN’s lab can visit the team’s booth at the career fair at the end of August, where they get a bulk of their applicants.

Outside of their lab on campus, CLEAN has volunteer opportunities for students who are interested in “getting [their] hands extra dirty,” according to Teirstein. 

Teirstein said the program now has the bandwidth to start gathering its own soil samples and is looking for student volunteers to help. 

Students interested in working in the lab or volunteering can email CLEAN to apply, according to Teirstein and Odendahl.

“If folks are interested in potentially getting involved in this kind of work, they should reach out to us,” West said. “We’re always eager to expand the group that’s working on this.”

CLEAN started as a wildfire response project, Teirstein said, but that’s not where it’s ending. 

Currently, the program has funding through 2027, but they don’t plan to stop there, according to Teirstein. 

Along with continuing to respond to fires, West said he sees the project as a long-term public health mission to increase awareness of L.A.’s high level of lead pollution.

“I would love to map the entirety of Los Angeles County with soil samples,” Odendahl said. “Let’s see how [the county] changed, and … help get people justice.”