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

The Trump administration sent shockwaves through the U.S. mental health and drug addiction system late Tuesday, sending hundreds of termination letters, effective immediately, for federal grants supporting health services.

Three sources said they believe total cuts to nonprofit groups, many providing street-level care to people experiencing addiction, homelessness and mental illness, could reach roughly $2 billion. NPR wasn't able to independently confirm the scale of the grant cancellation. The U.S. Substance Abuse and Mental Health Services Administration (SAMSHA) didn't respond to a request for clarification.

"We are definitely looking at severe loss of front-line capacity," said Andrew Kessler, head of Slingshot Solutions, a consultancy firm that works with mental health and addiction groups nationwide. "[Programs] may have to shut their doors tomorrow."

Kessler said he has reviewed numerous grant termination letters from "Salt Lake City to El Paso to Detroit, all over the country."

Ryan Hampton, the founder of Mobilize Recovery, a national advocacy nonprofit for people in and seeking recovery, told NPR his group lost roughly $500k "overnight."

"Waking up to nearly $2 billion in grant cancellations means front-line providers are forced to cease overdose prevention, naloxone distribution, and peer recovery services immediately, leaving our communities defenseless against a raging crisis," Hampton said. "This cruelty will be measured in lives lost, as recovery centers shutter and the safety net we built is slashed overnight. We are witnessing the dismantling of our recovery infrastructure in real-time, and the administration will have blood on its hands for every preventable death that follows."

Copies of the letter sent to two different organizations and reviewed by NPR signal that SAMHSA officials no longer believe the defunded programs align with the Trump administration's priorities.

The letter points to efforts to reshape the national health system in part by restructuring SAMHSA's grant program, which "includes terminating some of its … awards."

According to the letter, grants are terminated as of yesterday, Jan.13, adding that "costs resulting from financial obligations incurred after termination are not allowable."

The National Association of County Behavioral Health and Developmental Disability Directors sent a letter to members saying it believes "over 2,000 grants [nationwide] with a total of more than $2 billion" are affected. The group said it's still working to understand the "full scope" of the cuts.

This move comes on top of deep Medicaid cuts, passed last year by the Republican-controlled Congress, which affect numerous mental health and addiction care providers.

Kessler told NPR he's hearing alarm from care providers nationwide that the safety net for people experiencing an addiction or mental health crisis could unravel.

"In the short term, there's going to be severe damage. We're going to have to scramble," he said.

Regina LaBelle, a Georgetown University professor who served as acting head of the Office of National Drug Control Policy during the Biden administration, said the SAMHSA grants pay for life saving services.

"From first responders to drug courts, continued federal funding quite literally save lives," LaBelle said. "The overdose epidemic has been declared a public health emergency and overdose deaths are decreasing. This is no time to pull critical funding."

Requests for comment from SAMHSA and the Department of Health and Human Services were not immediately returned.

This is a developing story.

Copyright 2026 NPR

When the head of the nation’s largest publicly operated health plan worries about the looming federal cuts to Medicaid, it’s not just her job. It’s personal.

Martha Santana-Chin, the daughter of Mexican immigrants, grew up on Medi-Cal, California’s version of Medicaid, the government-run health care program for people with low incomes and disabilities. Today, she is CEO of L.A. Care, which runs by far the biggest Medi-Cal health plan with more than 2.2 million enrollees, exceeding the Medicaid and Children’s Health Insurance Program enrollments in 41 states.

“If it weren’t for safety nets like the Medi-Cal program, I think, many people would be stuck in poverty without an ability to get out,” she said. “For me personally, not having to worry about health care allowed me to really focus on what I needed to focus on, which was my education.”

As she begins her second year steering L.A. Care, Santana-Chin is grappling with federal and state spending cuts that complicate her task of providing health care to the poor and medically vulnerable enrollees in Medicaid. The insurer also provides Affordable Care Act marketplace plans through Covered California.

Santana-Chin warns that the GOP’s One Big Beautiful Bill Act, enacted last year and also known as HR 1, could result in 650,000 enrollees falling off L.A. Care’s Medi-Cal rolls by the end of 2028. This will strain the plan’s finances as revenues decline. The insurer had revenues of $11.7 billion in the last fiscal year.

HR 1 is expected to cut more than $900 billion from Medicaid over the next 10 years — including $30 billion or more in California, according to the Department of Health Care Services, which runs Medi-Cal.

Like other states facing big deficits, California has reduced its Medicaid spending through such steps as freezing new enrollments for immigrants without legal status and reintroducing an asset limit. And that’s before the state reckons with the spending cuts that likely will be required by the withdrawal of so many federal dollars under HR 1.

Santana-Chin oversaw Medi-Cal and Medicare operations for the for-profit insurer Health Net before taking the helm of L.A. Care in January 2025, nearly three years after state regulators fined L.A. Care $55 million over violations they said compromised the health and safety of its members. L.A. Care paid $27 million in penalties to the state and agreed to contribute $28 million to community health projects.

In a wide-ranging interview, Santana-Chin talked to KFF Health News senior correspondent Bernard J. Wolfson about the financial headwinds facing L.A. Care and why she believes health care shouldn’t be restricted based on a person’s immigration status. This interview has been edited for length and clarity.

Q: You grew up on Medicaid. How has that shaped your views now that you run one of the largest Medicaid plans in the country?

What really motivates me is knowing that many of the people that we’re serving are just like my family. They’ve struggled and have had to have their own children translate things that were very difficult to translate. I remember doing that for my own mother. You know, basic human dignity requires that you have access to health care.

Martha Santana - Chin, CEO of L.A. Care, is the daughter of Mexican immigrants and was a beneficiary of Medi - Cal throughout her childhood. Because of that experience, she says, the concerns of L.A. Care members resonate with her on a personal level.

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Q: Has anything you’ve dealt with at Health Net or L.A. Care reminded you of your childhood experiences in Medi-Cal?

Back then they didn’t cover transportation, and we didn’t have a vehicle. Today, one of the issues we’ll hear from our members is the need to make sure we have trustworthy transportation that shows up on time, where the drivers treat them with respect. Had I had that, had my mother had that, life would have been much easier.

Q: What do you think the impact of HR 1 will be?

It’s going to devastate the delivery system. The state obviously isn’t going to be able to make up for the shortfalls in federal funding, and over the course of the next several years, funding is going to be less and less, and the people we cover are going to decrease significantly. We are expecting between now and the end of 2028 that we’re going to see 650,000 people drop off the rolls. That’s just L.A. Care.

Q: That’s over a quarter of your Medi-Cal enrollment.

Yes, it’s very, very significant. The reductions in payment and the rise in uncompensated care are really going to impact our delivery system. As the delivery system gets destabilized and hospitals and other health care providers are forced to close services or reduce the number of sites they have, it’s going to impact access. And it’s not only going to impact those that lose coverage.

Q: How will L.A. Care respond?

Obviously, we’re going to see a significant drop in revenue. We’re very focused on making sure that we are operating as efficiently as we can operate. And we are looking at creative ways to use technology to empower our people to do higher-level work. Mostly supporting our call center agents with smarter technology that helps them answer questions and resolve problems more quickly. Some of it is automating processes on the claims payment side.

Q: What do you have to say to congressional Republicans who passed HR 1?

We are at a point of inflection in the health care delivery system. And we have to recognize that some of the components of HR 1 will have long-term unintended consequences — maybe they were intended; I’ve got to believe that some of these things are not. There’s probably a need to reconsider some of the things that were passed.

Q: Such as?

Work requirements are an example of something that many people did believe was the right thing to do to be good stewards of the health care dollar. It is very complex and is going to cause people to lose coverage that actually do qualify. It’s unfortunate, and that would be something that I would urge folks to reconsider.

Q: What impact do you expect from California’s decision to freeze Medi-Cal enrollment for immigrants without legal status?

It doesn’t matter what immigration status you are. If you are a human being and you need health care, you’re going to try to access health care wherever you can. That’s going to put a strain on the delivery system if you’re uninsured.

Q: What has L.A. Care done to address the state’s concerns in 2022 that it delayed authorizing care and addressing patient grievances?

There has been quite a bit of investment in the L.A. Care infrastructure over the last several years — our IT platforms, our data. There’s also quite a bit of investment in adding new capacity, adding bandwidth to many of the teams, more folks to help support the work.

Q: How have federal immigration raids in L.A. affected L.A. Care members and the broader community?

It absolutely has had a chilling effect. Families are afraid to come in. They’re not taking their children to get vaccinated. I’ve had numerous providers in emergency departments say that they have experienced a drop in the volume of individuals coming in. One of our case managers was really distraught because there was an individual that decided to forgo serious lifesaving treatment because of fear.