The Brief

After the Eaton Fire, many homes remained standing but were coated with the ashes of structures that burned. Post-fire testing showed these surviving homes contained lead, asbestos and other heavy materials that pose a risk to human health.

On Thursday, a group of residents released results from a new round of testing in dozens of homes. The findings show contaminants remain present in many homes, even after professional cleaning.

Francois Tissot, a CalTech geochemistry professor who was not involved in the effort, said the results are concerning.

“I personally was expecting that the values post-remediation in most houses would look really good,” Tissot said.

Instead, 63% of tested homes had lead on their floors at levels far above EPA screening thresholds.

It’s a result Tissot called “worrying.”

Digging through the data

The results came from 50 homes in the Altadena area. The data was compiled by Eaton Fire Residents United, a group formed after January’s historically destructive fire. Ten of those homes had been included in the group’s previous release of pre-remediation testing data.

Most of the homes (78%) in the latest round of testing had been cleaned by a professional remediation company. The other 22% were do-it-yourself jobs performed according to public health recommendations.

The testing was performed by various licensed industrial hygienist testing companies, and it was paid for either by insurance providers or out-of-pocket by homeowners. Only about half the homes were tested for asbestos.

The lack of consistency across testing is one of the limitations inherent in figuring out ongoing health risks, said Nicole Maccalla, the resident group’s data science director.

“There is a need for standards in this industry,” Maccalla said.

About one-third of the cleaned homes (36%) that were checked for asbestos tested positive. Not every home was tested for the presence of heavy metals. But among six homes that were, all returned positive results for chromium, barium, copper and zinc.

Dawn Fanning, the resident group’s managing director, said regulators should take these results seriously because asbestos has been linked with lung cancer, lead has been linked with neurological problems (especially in children and pregnant women), and heavy metals can cause kidney and liver damage, among other health issues.

“We don't want to alarm people, but we don't want them to live in unsafe homes,” Fanning said. “This is why we're asking elected officials to roll up their sleeves, get involved and do what needs to be done to make sure that every home is safe.”

Is normal cleaning enough?

Organizers from the group said they want elected officials to ensure homes are tested and fully clear of contaminants before residents are told to return. They said until full clearance is achieved, insurance companies should be required to extend relocation benefits for displaced residents.

Tissot, the Caltech scientist, said more data is needed to fully understand the health risks present in cleaned homes. For example, he said children living in the area should be given blood tests for lead.

Tissot said his own lab plans to test remediated homes for the presence of harmful substances, independent of the Eaton Fire Residents United project. He said it’s possible that cleaning standards that are sufficient in rural areas may not be enough to fully clean homes where thousands of structures burned.

“Most of those protocols are established based on wildfires which do not contain a very high amount of heavy metals to begin with,” he said. “But maybe the cleaning protocols are insufficient for urban fires.”

Eaton Fire Residents United leaders, who have been navigating their own path toward cleaning their homes, recommend that concerned homeowners run HEPA air filters and leave shoes outside.

Those precautions are a start, but they say it’ll take advocacy — and pushing insurance companies to cover post-remediation testing — for homeowners to feel confident about re-entering a healthy home.

Scientists have now gotten closer to understanding how gene mutations may lead some people to develop profound autism.

The clues, they say, lie in the murky space between genes and disease — where key proteins come together and interact.

A team of researchers from UC San Francisco mapped more than a thousand interactions between many proteins that come from certain autism risk genes. This molecular atlas, published in the journal Science, could point researchers toward new and promising treatments.

"It's an unprecedented resource for the field," says Dr. Daniel Geschwind, a professor of human genetics, neurology, and psychiatry at UCLA who was not involved with the study. "A lot of people interested in understanding autism and drug development are going to be using this."

For families affected by profound autism, it offers hope for eventual drug therapies. "This is the kind of scientific advance we have been waiting for and praying for," says Alison Singer, president of the nonprofit Autism Science Foundation, who has a daughter with severe cognitive impairment. "There's still a lot of work ahead, [but] this paper makes the path from genetic discovery to treatment much clearer."

The work builds on progress made in recent years to identify single genes that harbor mutations found in a subset of individuals with profound autism.

Getting past the "wall"

People with profound autism often live with severe intellectual disability and require around-the-clock care. They're nonverbal or minimally verbal, and often have serious medical conditions like epilepsy.

Pinning down the biology behind profound autism has always been a complicated endeavor — while both genes and environmental factors play a role, those factors can vary widely from person to person.

In the past decade or so, some genetics researchers have had remarkable success in identifying high-impact genetic differences in a subset of people with profound autism.

"They've discovered several hundred genes and corresponding mutations that are prevalent in [these] individuals," says Nevan Krogan, director of the Quantitative Biosciences Institute at UC San Francisco.

"But they kind of hit a wall," he added — because scientists haven't been able to turn those gene discoveries into many promising drugs and treatments.

"There was this huge missing piece," says Dr. Matthew State, a clinical psychiatrist and geneticist at UCSF: The genes serve as blueprints for making proteins that drive brain development, but researchers lacked visibility into how those proteins do the work.

State has been a pioneer in identifying high-risk genes, and the mutations in those genes, that are associated with profound autism. Krogan has been at the forefront of using new technology to look into protein interactions.

More than a decade ago, the two researchers were introduced by their mutual boss, the chancellor at UCSF, who encouraged them to collaborate. "[State] had the genes and the mutations. I had the technologies to look at the corresponding proteins," Krogan says.

They focused on filling a knowledge gap. "What we've been missing is the mechanistic understanding of how these mutations [on the genes] are seemingly resulting in autism," Krogan says. "In order to understand that, you need to go to the proteins."

Proteins are the complex molecules that come together to build the body, based on instructions encoded in the genes. "What makes an eye cell an eye cell, and a muscle a muscle, are the proteins and how they work together," State says. "They are the machinery of life."

In this case, the researchers wanted to find the molecular machinery of profound autism — to understand which proteins came from those high-risk autism genes, and how those proteins worked together.

The research was slow at first, but more recent advances in technology — including artificial intelligence — have sped things up.

To start, the researchers went on a "fishing expedition" for protein interactions. They chose 100 proteins from these high-risk autism genes, injected them into lab-grown cells, and then pulled them out, along with the additional proteins that attached to them.

Then, they used an AI system called AlphaFold, developed by Google DeepMind, to help determine which proteins in the clumps were directly touching. "Where AI is playing an important role is being predictive about who's talking to who," says Krogan. "Sometimes they take years to figure out. Now, we can get these insights in an hour." While imperfect, the system has worked well enough to save significant time and money, Krogan says.

Then, they wanted to see what happened to the proteins when the genes got tweaked. They introduced mutations that appear in patients with profound autism, and assessed what changed. "We broke the proteins in the way that they're broken in autism," says State. "That allows us ultimately to answer the question of, when they're going wrong in autism, how are they going wrong?"

They conducted this research in frogs and in organoids, which are lab-grown tissues that model the human brain. In one example, the mutations weakened the connection between two proteins related to which genes turn on and off in a cell. Then, one went rogue, turning on other genes that led to neurodevelopmental defects in organoids.

Molecular convergence

There are hundreds of rare, high-risk autism genes, acting in more than a thousand different ways.

But in mapping more than 1,800 protein interactions, the researchers found that many of them moved along shared biological pathways — particularly those related to early brain development, such as how synapses get constructed, and which neurons develop and when.

The convergence found in this study aligns with other recent publications, adding to an emerging understanding in the field, says Dr. Geschwind of UCLA.

"If we look at multiple mutations and they converge on the same process, that's strong evidence that you're dealing with the things that you want to treat," State says.

Identifying this more limited set of protein complexes that likely contribute to the development of profound autism could change the approach to treatments, says Singer with the Autism Science Foundation. "We've been working gene-by-gene to correct mutations," she says.

And if future drugs could target these shared protein pathways, she adds, "we may not need that separate therapeutic strategy for every autism gene."

Setting sights on new drug-development targets

It takes years to go from a biological discovery like this to an approved drug that treats humans. The findings would need to be translated into drug candidates, then tested for safety and effectiveness.

"It takes time and a lot of persistence and focus," State says. "This [paper] is unlikely to lead to therapies tomorrow — but it lays an important foundation for them."

Most human drugs are made to target proteins, Geschwind at UCLA says, so the newly published map of protein interactions offers an accessible entry point for pharmaceutical development.

And researchers hope to combine recent technological advances in ways that accelerate that progress even more. "When you put together the ability to borrow from successes in other fields [such as cancer treatments], and the development of AI, we're at an inflection point that will hopefully shorten the time cycle," State says.

Last week, Krogan's Quantitative Biosciences Institute received a $46 million grant from the Aligning Research to Impact Autism initiative, funded by philanthropist and Google co-founder Sergey Brin. The researchers are already working on next steps.

Copyright 2026 NPR

As Gov. Gavin Newsom weighs whether to require data centers to disclose how much water they use, OpenAI CEO Sam Altman says concerns over AI’s water use don’t hold “up to any scrutiny.”

On the Sources Podcast with Alex Heath released Tuesday, Altman said that it takes 38,000 ChatGPT queries to use as much water as producing a single almond in California.

“If you look at a modern very large data center, it uses the equivalent amount of water as an office building in terms of, you know, people like running the sinks and the toilets and whatever,” Altman told Heath.

The problem, experts say, is that it’s impossible to verify those numbers given what’s public about the secretive industry.

“The information we have is so limited,” said Shaolei Ren, a professor of electrical and computer engineering at UC Riverside.

Far too many factors affect how much water data centers use to boil it down to any one convenient statistic, Ren said, rattling off a handful of variables: the data center’s location, the temperature outside, the type of cooling system, the length of the prompt, the reasoning required, the output. All affect how much water the data center uses.

“This is the whole reason that these bills need the governor’s signature,” said Michael Kiparsky, director of the Wheeler Water Institute at the UC Berkeley Center for Law, Energy, & the Environment. “There’s no published data — certainly not for California — and what is public seems all over the place.”

Over the past two weeks, California lawmakers passed two bills by Assemblymember Diane Papan aimed at increasing transparency; both now await Newsom’s signature.

One would require operators to report their water sources and usage when seeking business permits. The other would block local governments from approving new data centers unless developers disclose their water plans. They’d also have to pay for any water upgrades needed to connect to the local supply.

It’s the San Mateo Democrat’s second attempt at more transparency around data center water use. Newsom vetoed her bill last year, saying he was “reluctant to impose rigid reporting requirements … without understanding the full impact on businesses and the consumers of their technology.”

The heavy-hitting tech industry and business groups again opposed the bills. But now, as data center fights erupt across the state and local governments ban the facilities outright amid a wider bipartisan backlash, the question of how much water data centers really use is gaining urgency.

“If we know what an almond uses, maybe we can figure out what a data center uses?” said Alex Biering, director of policy advocacy who specializes in water issues for the California Farm Bureau Federation.

What the data actually shows

Regardless of whether it takes thousands of queries to match the water needed to produce a single almond in California (a number that varies substantially over time and space, according to a 2019 study), the Congressional Research Service says data centers are using more water than they used to. 

One study reported the facilities directly used about 17 billion gallons in 2023, up from 5.6 billion gallons in 2014. Another report found that hyperscale data centers could use 150 billion gallons of water from 2025 to 2030 — which is as much water as 4.6 million households use in the U.S. in a year.

Annual water use isn’t the whole story, Ren cautioned. The hottest days, when data centers require the most cooling, can substantially increase peak water demand, according to Ren’s research, which is under review by a scientific journal and available online as a preprint.

“For community water systems, the peak capacity is more important because they need to be designed and built to accommodate the peak demand at all times, similar to our power grid,” Ren said.

Ren’s team found that data center cooling systems could call for 697 to 1.45 billion more gallons of peak water capacity per day. It’s comparable to New York City’s average daily supply, the study says. And unlike irrigation water typically used for farms, water for data centers is often treated, potable water from public water systems, the team reported.

That’s a problem, because water systems across the country — and certainly in California — are “aging, fragmented, and/or financially constrained, thus lacking sufficient available capacity to meet the additional peak water demands of large data centers.”

The researchers pointed to examples in Georgia and Virginia where water suppliers worried they “just don’t have the water” to accommodate peak demand from the data centers drawing from their systems simultaneously.

Ren said water use could drop by as much as 50% if data centers opt for less water-intensive cooling systems, like dry cooling, but there are tradeoffs — such as increased energy needs.

And that, too, requires water.

With a little more than two months to go until the general election, the two mayoral candidates running to lead the city of Los Angeles fielded questions about the environment at a Thursday night forum hosted by LAist.

Incumbent Karen Bass and her challenger, L.A. City Councilmember Nithya Raman, each answered questions separately about how they would approach many environmental challenges facing the city, including emergency preparedness, water resiliency and transportation policy.

These and other environmental and climate issues are top of mind for many Angelenos during a summer marked by extreme heat, humidity and the Lineage warehouse fire in Boyle Heights that affected surrounding neighborhoods for months. Communities are also still rebuilding from last year’s destructive Eaton and Palisades fires.

The forum, held at Los Angeles Trade Technical-College, was organized by the L.A. League of Conservation Voters, SCOPE-LA, Sierra Club, Clean and Healthy California, Neighborhood Council Sustainability Alliance and Communities for a Better Environment, and was moderated by LAist climate and environment Reporter Erin Stone.

Here are three takeaways from the event:

Differing visions of LA

Bass, who was elected mayor in 2022, painted a picture of an L.A. that’s made significant progress on environmental issues during that time, while Raman said the city has stalled under Bass’ leadership.

Bass referenced her work transitioning the city off of coal-generated energy and expanding the city’s electric bus fleets and clean-energy jobs. She said she wants to build on that momentum, particularly with a focus on helping communities impacted by environmental and industrial pollution.

She pointed to many communities of color that bear the brunt of industrial pollution, including in South L.A. neighborhoods dotted with oil wells and residents who live in close proximity to the Lineage warehouse in Boyle Heights.

“Where we need to go now in the future is focusing on environmental justice, focusing on the communities that are disproportionately impacted by greenhouse gases and by the environment,” she said.

Raman also talked about a need to focus on environmental justice, but she said environmental programs are underfunded and understaffed, and that she would invest more in them if she becomes mayor.

She said Bass’ administration has not prioritized environmental climate issues enough, and that there should be a more aggressive policy around them.

“Too much of that work remains unfinished,” she said. “Our transition to clean energy has slowed. Efforts to build a resilient water supply, close neighborhood drilling sites, make our streets safer, all of these have slowed over the last four years.”

Raman specifically called out Bass for her proposal to cut funding for the Climate Emergency Mobilization Office as the city faced a billion-dollar budget shortfall last year.

Bass defended the proposal, arguing the program had not developed a climate action plan as directed and needed to be revamped.

The office has shrunk under Bass’ leadership, and she removed the city’s chief heat officer and quietly appointed a new one earlier this year.

Emergency response failures

Both Bass and Raman said L.A. has room for improvement when it comes to preparing for fires, earthquakes and other disasters.

Raman criticized the city’s response to last year’s Palisades Fire, saying there was no clear leadership to guide the community through the recovery effort. She pointed to Bass' appointment of Steve Soboroff to head the recovery. He left the post after his three-month term and was not replaced.

 ”What we saw in the Palisades, I think, was an example of what shouldn't happen,” Raman said. “ A lot of residents in the Palisades have been feeling like they don't know who to reach out to, who is the person that they need to connect with in order to make sure that recovery really happens.”

But she defended her administration’s response, and said confusion over city and state land made it more difficult.

 ”Part of the brush was the city, part of the brush was the state. There was a reluctance to go into state territory because our folks were told they couldn't do that,” Bass said. “As far as I'm concerned, that's not gonna happen again.”

Bass said the biggest impediments to the recovery process — and to people moving back into their homes — are insurance companies and banks. She called for legislative reforms to the insurance process.

Raman also criticized the response to the Lineage warehouse fire in Boyle Heights this summer, calling out Bass directly for sharing misleading information about air quality.

Bass said she relied on inaccurate information from public health and air quality management officials.

Both candidates said there’s a need for stronger enforcement and higher fines that could be levied against corporations like Lineage, the warehouse owner, and better planning for emergencies around industrial buildings.

Shared goals

Although the candidates leaned into their differences, the reality is that they align on many climate and environmental policies.

Unhoused Angelenos are especially at risk from extreme heat, and Bass said the city needs to provide more places for them to cool off.

“My plan, priority one, is to get people off the streets,” Bass said, adding that during heat emergencies that needs to include providing emergency shelters and other ways to cool off.

Raman talked about similar solutions.

“ Responding to people who are experiencing homelessness to ensure that they're actually able to get indoors and off the streets, so that they're not dying from exposure to heat, because that is a very, very high risk that people who are experiencing homelessness face,” she said.

They had other shared goals.

Both said incentives and rebates that keep down the cost of utility bills need to be more accessible, especially in low-income communities.

Both called for more severe penalties for owners of industrial sites like the Boyle Heights warehouse.

And they both said they want to grow the city’s electric vehicle fleet, and decrease car use by building more public transit ridership and expanding biking infrastructure.