The Brief

Last January, fires were raging across Los Angeles, smothering some 20 million people across the region in toxic smoke and ash.

L.A. residents worried that the air was toxic, the soil contaminated, and the water poisoned. Questions swirled about the health risks created by the burns — and there were few answers at hand from city, state or federal leaders.

Scientists from Los Angeles and around the country quickly scrambled into action as fires burned through the Pacific Palisades and Altadena. The priority, says UCLA physician and disaster researcher David Eisenman, was keeping people safe in the short term. But the fires also presented a moment to learn crucial missing information about the health effects of wildfires to help those affected and to better protect people's health from the inevitable next ones.

"This won't be the last wildfire that Los Angeles sees," says Eisenman. "Part of the community recovery process is to learn from what we experienced."

Researchers fanned out across the city to collect what data and samples they could. Doctors started thinking of ways to collect patient data to better understand the immediate and long-term health impact. They soon joined together to form a consortium that tied together 10 research institutions, developing a phalanx of research studies to explore some of the most pressing questions brought up by affected community members.

Some questions were simple but frustratingly hard to find answers to, like: What was in the smoke? Other questions, like those exploring the long-term health impacts, will take years to untangle. But answers are beginning to emerge.

Extra-dangerous smoke

Wildfire smoke is dangerous under any conditions. Exposure to high smoke levels is linked to respiratory problems such as asthma and COPD, cardiovascular issues and even dementia.

But from the first moment the Palisades and Eaton fires took hold last January, UCLA air pollution expert Yifang Zhu knew they were different. Because it wasn't just trees and plants burning: There was plastic from people's houses, and car batteries and asbestos tiles — a "toxic soup" of air pollutants, she says.

What was in that soup, and how dangerous it might be to human health — that wasn't clear. Official air quality monitors in downtown Los Angeles, miles away from the heart of the fires in Altadena and Pacific Palisades, recorded high levels of lead and arsenic in the air during the burns. Researchers from Caltech and the Georgia Institute of Technology later measured lead concentrations in air samples both near and far from the fires. Lead levels, they found, were elevated, even miles away, signaling that smoke and ash from the burns spread the dangerous heavy metal widely.

But many scientists suspected the smoke and ash spread other toxic particles and gases widely, too — chemicals that standard EPA and state monitors didn't test.

"We need to test more than just what the EPA calls for. And the EPA has limited resources," says Kari Nadeau, an environmental health scientist at Harvard University and one of the leads for the new research consortium. "But as academics, we can test for hundreds of things all at once, which helps the community. Because what you don't know, you don't know, but it can still hurt you."

Before the fires, Zhu and her team had been getting ready to sample the air at Aliso Canyon, where a natural gas leak in 2015 had caused major health problems for nearby residents. When the fires broke out, the team pivoted, taking their sampling equipment as close to the fires as they could.

That opportunity was special. Researchers are rarely ready to deploy at a moment's notice to capture samples during disasters such as the LA fires. The special circumstances let Zhu's team "set the stage about what's going on during this active fire burning all week," Zhu says.

Dust and ash from the Palisades and Eaton fires spread across the Los Angeles region.

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Zhu's team set up air filters to capture the ash, and they captured air samples inside and outside homes in the Palisades and Eaton fire regions. In the air samples, they looked for more than 20 different volatile organic compounds — gases, many of which harm human health, and are likely to be produced by the fires. And while the fires were still burning, they measured high levels of benzene, a carcinogen, at their outdoor sites.

Lingering risks

The high benzene levels dissipated after the burning stopped, Zhu found. But other dangerous gases actually increased later on, especially indoors. A few health-harming gases, including toluene and carbon tetrachloride, became more concentrated inside people's homes a few weeks after the fire.

The message was clear. "The fire impact doesn't really disappear with the active flame," Zhu says. Homes themselves can absorb dangerous gases in the drywall, furniture and other soft materials, releasing them for days and weeks after the smoke has dissipated. People need to know that their homes might be contaminated long after the fire is out, she says.

That wasn't the only lingering risk. Another research team started to look for a contaminant called hexavalent chromium, which can cause cancer, sometimes known as the "Erin Brockovich" contaminant, made famous by the movie of the same name. It can be produced when fires burn through certain types of soil or rock, as well as during industrial processes like welding. It's not often searched for after wildfires, but the researchers found it lingering in the air around cleanup sites long after the fires were out.

"It's actually one of those things that … makes you pay attention differently," says Joe Allen, an exposure scientist at Harvard University, who has been conducting ongoing research on building safety after the fires. And the contaminant was found in tiny particles so small that they can penetrate deep into people's lungs, bodies, and even directly to their brains.

"We've seen hexavalent chromium in soils after fires. I don't think anybody expected to see it in air. I don't think anybody expected to see it exclusively in the nanoparticle size range," Allen says.

Ash also contaminated people's homes, as well as soil and water across the region. The water impacts seemed to clear quickly, though longer-term effects are still being tracked. But levels of lead and other heavy metals inside people's homes and in the soil around them often remained high, even after cleanup was supposedly done.

"That is an ongoing question," says Allen. "Do we have enough funds to remediate all these properties, or are we just putting some people back into properties that are not properly cleared?"

Zhu was impressed by how much she and others learned about the dangerous smoke and ash. But she also worries they probably only scratched the surface. "We are only detecting things that our method allows us to detect. So even though we learn a lot from that, you know, I wonder what we missed," she says.

What does this all mean for people's health?

Scientists have known that in the short term, wildfire smoke exposure leads to more respiratory issues, such as asthma and COPD; increases the risk of developing dementia; and affects people's immune responses. But the full array of impacts, and the long-term costs of exposure, are still muddy.

"We know a lot about the health effects of wildfire smoke," says Allen. But "we don't know all that much about urban wildfire smoke. We certainly don't know what happens when you expose a population of 20 million people in the greater Los Angeles area to smoke like this, enriched in these toxic metals and other pollutants. "

The research is beginning to uncover some of the health impacts.

Cheng and colleagues collected data from the emergency room at Cedars-Sinai, one of the busiest in the region, and particularly close to the Palisades fire. In the 90 days following the fires, they saw a 24% increase in respiratory issues — and a 47% jump in heart attacks.

It was "very striking," she says. "This actually surpassed heart attack rates during January of all prior years, even during the worst years of COVID."

Homes and businesses in parts of Los Angeles were reduced to rubble and ash.

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Abnormal blood tests also spiked, increasing by more than 100% over previous levels. That included unexpected blood sugar readings, signs of a disrupted immune system, and changes to people's metabolic profiles — signals, Cheng says, of bodywide stresses that could be precursors to many different health problems down the line.

"For a very large number of people who lived through these January wildfires, the wildfire exposures led to some kind of a biochemical or metabolic stress in the body that likely affected not just one, but many organ systems," she says.

The team is now tracking some of those patients, trying to understand what health issues their unusual bloodwork might have signaled coming.

The ER data is likely just skimming the surface, says Eisenman. Longer-term health problems, from heart issues to mental health stresses, are likely to linger or develop in the coming years.

Ongoing research will explore the different health outcomes for people who experienced different levels of smoke and toxin exposure. A UCLA-led study has enrolled over 4,000 people from across the city to follow their health changes long-term. Another study will focus on the specific health outcomes for those who stayed behind at their homes to fight the fires, giving them extraordinarily high smoke doses. The LA Fire Health study consortium is also tracking the long-term health impacts on firefighters and first responders.

Much of the emerging research is being supported by private philanthropy, says Eisenman. The wildfires happened just before the Trump administration began its campaign to tighten budgets for many of the science agencies that have historically funded post-disaster research, like the National Science Foundation.

"That gap was really filled in by the research community, who did ongoing and extensive and really thoughtful testing of air, of water, of soil, of debris for toxins, and really rapidly communicated those results back to the community," he says. But how to financially support the long-term future of some key studies, he says, is still uncertain, because many major federal research funding resources — like NSF and the National Institute of Health — have shifted priorities under the Trump administration.

How to protect yourself and your family

The biggest questions for the ongoing research, many of the researchers say, are about how best to protect yourself from similar fires in the future.

Allen says there are some clear lessons. Overall, the less smoke one inhales, the better. So while outside, he says it's crucial to wear an N95 mask, or even a respirator that can protect you from the fire's gases.

Indoors, keeping clean air is crucial, says Zhu. Using air filters, ideally HEPA-rated, can lower indoor pollution significantly. Carbon filters are particularly effective at removing the gases, Allen says. People can also install HEPA filters in a car's air-handling system to keep the air clean while they drive.

"You want to control what you can control," says Allen. So inside your space, clean up dust and ash thoroughly. Filter the air. And consider a low-cost air monitor to keep track of the air quality inside.

For people most impacted by the fires, Allen stresses that adequate cleanup of soil and buildings is critical. "It was a bit of the Wild West out there" after the fires, he says. A lack of standardized testing protocols and a hodgepodge of policies from different insurers "really harmed the survivor community."

That lack of guidance left many unsure whether their homes were safe to live in again, and many others were forced to go back to homes that were demonstrably still unsafe.

"We need more coordinated recommendations and rules to help people know whether their homes are safe," Allen says.

It will take years to get a full picture of the health impacts of the LA fires, many of the researchers say. But it's critical to learn from the tragedy, says Nadeau, the Harvard environmental health scientist — to "be able to say, OK, in the future, here's what to do to protect your children or protect your elderly community against stroke," or lung cancer, or the myriad other risks from the wildfires that will, inevitably, come again.

Reporting for this story was supported by the Nova Institute for Health.

Copyright 2026 NPR

A news helicopter crashed in a Los Angeles neighborhood on Tuesday and burst into flames, killing at least three people near the scene of where an SUV had slammed into a city bus, officials said.

The helicopter crashed around 7 p.m. near a one-story commercial building in the neighborhood of Chatsworth in the San Fernando Valley, as news crews were covering the bus crash that left at least two people dead and six others injured, according the Los Angeles Fire Department.

An NBC4 Los Angeles anchor at the station confirmed during a live broadcast that its chopper went down just before 7 p.m.

At least one person killed in the helicopter crash was outside in the parking lot next to the commercial building, Capt. Branden Silverman, a spokesperson for the Los Angeles Fire Department, said during a news conference. It was unclear if the other two who were killed were on the ground or inside the aircraft.

The scene of a deadly helicopter crash in Chatsworth broadcast be CBSLA.

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One person was taken to the hospital, but their condition was not immediately clear.

“We’re trying to determine how many patients were inside the helicopter,” said Silverman, who described the helicopter as “pretty well destroyed” and adding that officials would be sorting through the rubble to see how many victims were on board.

At least four cars and two storage containers on the ground burned after the helicopter caught fire, which was quickly put out, according to officials. More than 50 firefighters responded to the helicopter crash, according to the fire department.null

Police and LA Metro investigate the scene of a crash between an SUV and a LA Metro Bus that left three people dead on Tuesday in Chatsworth.

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About two hours before the crash, an SUV slammed into the middle of a city bus, killing at least two people and injuring six others. Photos and videos online showed half of the SUV lodged into the side of an MTA bus.

The helicopter crashed about a mile and a half from the bus crash.

The National Transportation Safety Board and the Federal Aviation Administration said it will be investigating the cause of the helicopter crash.

This is a developing story.

The Los Angeles region’s lead homelessness agency is effectively forfeiting the federal administrative roles it has held for decades, including applying for millions of dollars in funding for the region and leading the annual homeless count, the agency announced Tuesday.

The decision comes as the Los Angeles Homeless Services Authority faces mounting criticism from both the Trump administration and local leaders who accuse the agency of mismanaging homeless services.

It reverses a monthslong legal battle LAHSA had been waging with the federal government to continue in these duties.

The city of Los Angeles, L.A. County and other entities and organizations are now applying to take them over.

At a county meeting Tuesday, Supervisor Lindsey Horvath called it “a fundamental change that reflects the significant performance, contracting and financial concerns that have plagued LAHSA for too long.”

“ Officials avoiding accountability will no longer have LAHSA to hide behind, and the county and city must be accountable to each other and to our entire Los Angeles region,” Horvath continued.

LAHSA's decision

In June, the U.S. Department of Housing and Urban Development suspended LAHSA from conducting its federal duties, including applying for or receiving grants, putting $241 million in anticipated funding and LAHSA’s future in limbo.

LAHSA sued.

U.S. District Judge David O. Carter paused LAHSA’s suspension on Aug. 13, but also instructed a regional planning body known as the L.A. Continuum of Care Board to solicit applications from other entities to replace LAHSA in those key roles.

The Continuum of Care Board opened its application process online last week, inviting qualified organizations to take on one or more of LAHSA’s current administrative roles.

LAHSA’s governing commission voted unanimously Tuesday to not apply, effectively forfeiting the federal roles that comprise most of its remaining responsibilities.

The city of L.A. and L.A. County are both applying, according to LAHSA.

“With both the City and County preparing their own applications, competing against our founding partners would only fracture regional collaboration during an already complex time,” the LAHSA Commission and the agency's leadership said in a statement.

“This decision reflects the shared judgment of LAHSA’s Commission and executive leadership,” the statement continued.

Federal roles

LAHSA will forfeit the following federal homelessness roles:

1. Coordinating and submitting annual federal homeless assistance funding applications to HUD on behalf of the entire L.A. region — about $240 million in the coming year.

2. Planning, executing and reporting the region’s annual point-in-time homeless count.

3. Operating and administering a HUD-mandated database that tracks who's being served and whether they're moving into housing.

4. Managing and operating a HUD-mandated system to match unhoused people to available housing and services based on need.

How we got here

After Carter paused LAHSA’s suspension, the federal housing agency appealed the decision to the Ninth Circuit Court of Appeals. Last week, the appeals court issued a temporary stay on Carter's order.

LAHSA said that ruling created more uncertainty about whether the agency was eligible to apply for the federal roles it has held for the past three decades.

“Stepping aside now supports alignment with the direction the City and County are heading with their applications, and focuses public resources where they belong: on the people who depend on the rehousing system every day,” the LAHSA statement said.

LAHSA is a joint powers authority between the city and county, created three decades ago to manage the region’s response to homelessness.

City and county officials are collectively responsible for LAHSA, which has administered federal, state, county and city homelessness funding across the region.

Citing LAHSA’s management problems, L.A. County pulled more than $300 million annual homelessness funding from the agency starting this year, choosing instead to administer the funds through a new county homelessness department.

The city of L.A. is considering a similar move away from LAHSA. Mayor Karen Bass and her election rival Councilmember Nithya Raman both say the city needs its own independent homeless system.

In the current budget year, 73% of LAHSA’s nearly $500 million budget comes from the city of L.A., 20% from the federal government and 4% from L.A. County.

What’s next? 

LAHSA said it will continue to fulfill its ongoing federal responsibilities “until those duties transition to a new entity or entities.”

The agency has agreements with the city of L.A. to manage programs and contracts through June 30, 2027.

The county’s Department of Homeless Services and Housing is applying to take over all four of LAHSA’s federal responsibilities, according to county officials. The city of L.A. is currently applying for at least two of those roles, putting the city and county in competition with each other.

“Moving forward, another entity will be leading the [Continuum of Care], which I believe should be the county, given our ability to most effectively administer contracts for our region,” Horvath said Tuesday.

Other organizations have also expressed interest. Better Angels, a homelessness nonprofit led by former L.A. mayoral candidate Adam Miller, contacted the court seeking to apply.

Applicants looking to take over LAHSA’s federal roles have until Sept. 25 to submit applications, but had to communicate their intent to apply by Sept. 15.

The applicants selected by L.A.’s regional Continuum of Care Board will have to be reviewed by HUD and the federal court.

The Los Angeles Unified School District’s falling enrollment and budget challenges are fueling conversations planned for later this year about potential school closures and consolidation.

“Our goal is not simply to have fewer schools; our goal is to have stronger schools, schools that are better resourced, schools that offer more programs for our students,” Superintendent Andrés Chait said during a school board meeting Tuesday. The superintendent shared a similar message in a video sent to families Monday.

LAUSD is spending more money than it brings in and has relied on reserves to fill the gap in recent years. In Tuesday’s meeting, district leaders presented an updated snapshot of LAUSD’s finances that shows steeper enrollment declines and lower state revenue and reserves than projected early this summer.

“That deficit spending is only possible while we have reserves and the very significant challenge that we’re facing as a district is that those reserves are being depleted very quickly,” said Saman Bravo-Karimi, the district's chief financial officer. “They’re eventually going to go negative and we can’t have negative balances as a school district.”

How is enrollment changing? 

Almost 4% fewer students are attending LAUSD schools this academic year compared to last year, according to preliminary data — nearly a percentage point lower than expected.

Bravo-Karimi said that each 1% drop in enrollment is a loss of about $20 million a year for the next three years because California funds schools based on how many students show up to class each day.

Fewer students have attended LAUSD schools over the last two decades, in part because of falling birth rates and the region’s high cost of living, but those declines were steeper than anticipated in recent years.

Board member Kelly Gonez said the schools in East San Fernando Valley communities targeted by federal agents have double the enrollment declines of other campuses.

“That increase in enrollment decline last school year was not a coincidence,” Gonez said. “Something changed … that is the presence of a federal administration that is attacking our immigrant communities.”

How is LAUSD approaching school closures?

The district pulled a scheduled vote Monday night on a $960,000 contract with a school closure consultant.

The district planned to work with Alvarez and Marsal to develop a framework for possible school closures, mergers or reconfigurations.

The firm’s priorities, as described on their website, include “maximizing investment value in education” and reshaping how institutions operate.

Alvarez and Marsal are also associated with several controversial decisions, including closing more than a dozen campuses during an overhaul of St. Louis schools in 2003 and faltering when contracted to restructure New York City schools' bus routes in 2007.

Several members of the public and a leader in the district’s teachers union spoke out against the contract and any similar future consultants.

“It’s hard for us to seriously work with this district to fight for more state funding when you squander limited funds you have on contracts with vultures and privatizers like the Alvarez company,” said Julie Van Winkle, United Teachers Los Angeles vice president.

Chait said the decision to remove the contract from consideration was in response to messages from school, community and district stakeholders over the weekend.

“One of the core leadership principles that I’ve always really tried to live by is to listen to folks, especially when they disagree,” Chait said.

Chait said the district needs external support to convene community meetings and compile and analyze data.

“This is arguably the most complex, the most difficult endeavor we will ever take on,” Chait said of school consolidations. “It will reset the footprint of our district for years to come.”

Chait said the district will begin holding community conversations related to school closures in the next few weeks and will share more details during a Sept. 22 meeting.

How did LAUSD’s budget become so strained?

The district’s current $20.6 billion budget projects a $2 billion deficit.

LAUSD approved raises for teachers, principals and support staff earlier this year at the cost of an additional $1 billion this school year. LAUSD, like other districts in the state, also faces increased costs for employee health care, settlements for decades-old sexual assault claims and services for students with disabilities,

L.A. County education officials approved the district’s most recent budget Tuesday on the condition that LAUSD provide additional information about how it is implementing cuts this school year.

However, L.A. County Superintendent Debra Duardo also called out the district's “unsustainable” use of reserves.

“The district’s fiscal status necessitates continued monitoring for both immediate and future corrective actions,” Duardo wrote in a letter to district leadership, referencing the July appointment of a fiscal expert to advise the district.

LAUSD’s board has approved a series of plans to reduce spending and increase revenue. For example, the district eliminated hundreds of jobs, primarily in its administrative offices, earlier this year.

The district’s most recent fiscal stabilization plan includes furlough days for all employees, the elimination of thousands of jobs and cuts to programs that help high-needs schools pay for counselors, tutors and other student supports.

Most of these cuts aren’t scheduled to go into effect until the 2027-28 and 2028-29 school years.

The leader of a congressional panel warned Tuesday he would use “every tool” to get Los Angeles Mayor Karen Bass to testify after she skipped a hearing that put L.A.’s homeless services system in the hot seat.

It came as multiple audits, reviews and court rulings have found L.A. has failed to ensure proper tracking of large-scale spending on homeless services — particularly through the joint city-county L.A. Homeless Services Authority, known as LAHSA. Much of the money is federal dollars authorized by Congress.

Bass had declined to testify at Tuesday’s hearing, saying she was unavailable and that it would be a “politically motivated” attack. Her public schedule showed she planned to attend a groundbreaking of a shopping and community center in the Pacific Palisades two hours after the hearing was set to start.

Rep. Tim Burchett, the Tennessee Republican who chairs the House Oversight Committee's DOGE subcommittee, said she won't get off that easily.

Bass "seems intent on evading accountability, but she knows we will not let her off the hook," Burchett said at the hearing. He added that he and the Oversight Committee’s chair would "use every tool at our disposal to secure her appearance if she does not cooperate.”

House committees and subcommittees can issue subpoenas to compel witnesses to testify or provide documents.

Just before the hearing got underway, Bass called it "the latest attack on Los Angeles by the Trump Administration and his allies in Congress.”

"I don't run LAHSA," she said, adding that she was the first mayor to sit on its board and that street homelessness has dropped since she took office. The latest official count for the city showed a 8% year to year jump in street homelessness.

Bass stepped off LAHSA’s governing commission last week, after LAist reported she had missed most of its meetings since she appointed herself to it in 2023. The mayor cited “time and all” as her reason for stepping down. She continues to appoint — and has the power to remove — half the commission’s members, including its current chair.

What happened at the hearing

Much of the hour-and-a-half hearing focused on Republican members’ criticism that Democrat-led cities distribute drug paraphernalia and don’t require unhoused people with addictions to get treatment as a condition of living in publicly funded housing.

Some proposals raised Tuesday would change how money reaches Los Angeles.

Burchett said he will introduce the Recovery First Housing Act, to require federally funded housing to offer substance abuse treatment. He has also introduced a bill restricting federal housing dollars to only support U.S. citizens.

LA's fights on a national stage

Burchett noted LAHSA’s audit committee chair, Justin Szlasa — who was proactive in rooting out wasteful spending — was demoted by Stephanie Graves, a Bass appointee who has declined to give her reason for doing so. The move was first reported by LAist.

Burchett also made claims that don’t hold up. He said 50,000 people are homeless in the city with "another 75,000" in the surrounding county. The latest official count found a total of 73,000 unhoused people across L.A. County — a figure that includes the city.

Burchett also said, “ LAHSA recently doled out funds to an L.A.-area nonprofit whose CEO had just been indicted for fraud.” LAist recently investigated LAHSA’s awarding of funds to that nonprofit, Abundant Blessings, and found no indication that LAHSA awarded it any funds after the fraud indictment. However, the review did find that long before the indictment, LAHSA kept awarding millions in contracts to the group even after it was flagged internally as high-risk for failing to do its job.

Burchett, however, was correct in saying “a court-ordered independent assessment of LAHSA's finances found alarming financial control weaknesses that leave the door open to rampant fraud.”