A string of rare childhood cancer cases in this California suburb has the community on edge
By Julia Vargas Jones, CNN
(CNN) — On January 10, 2026, Lilly Dalton wrote her last Instagram post.
“I can’t believe I’m making this post, but today I entered hospice care.”
The 23-year-old from California who spent her childhood as an overachiever, graduating valedictorian and going on to earn a degree in history, was supposed to be beginning her career.
Instead, she had endured aggressive cancer treatment for a year and a half, and now, her liver was failing.
“Doctors aren’t sure how much longer I have left but I’m finding the little joys in every single one of my days,” she wrote under a picture of herself smiling, brown locks gone, in front of the Hollywood sign.
Lilly had gone to the emergency room with stomach pain just three days after graduating from university in 2024. She was initially sent home with a gastritis diagnosis but returned the next day, and after some scans, doctors found a tumor on her liver, her father said.
It would be at least three months before she would be given a more complete, earth-shattering diagnosis: Desmoplastic small round cell tumor that shares a genetic feature with Ewing sarcoma.
The family was told it was an extremely rare cancer.
Lilly did multiple rounds of what her father, Brian Dalton, described as “Red Devil chemo,” known for its red color and intense side effects, along with two types of radiation and major surgery.
Despite it all, she always had a smile on her face. “All the nurses loved her there. She was like a celebrity,” Brian said. “She was always the best dressed. Her pajamas game was the best.”
“My biggest regret is that I always thought she was going to make it,” the father said.
Lilly died on January 25, leaving her father to grieve her loss while shouldering a mission to spread awareness about the cancer that took his daughter’s life.
So, months later, when Brian heard that multiple children had been diagnosed with Ewing sarcoma in Ladera Ranch, a neighboring Orange County community where he says Lilly spent much of her childhood and teen years in, it set off alarm bells.
“There’s absolutely no way that this is a coincidence,” Brian thought.
A troubling question haunts a small suburb
Ewing sarcoma is so rare that only about 200 children and teens are diagnosed with it in the United States each year, accounting for 1% of all childhood cancers, according to the American Cancer Society. It typically starts in the bones or surrounding soft tissue, most commonly among adolescents and young adults.
Though little is known about the cancer, it was becoming more familiar in Ladera Ranch this spring, and anxiety has been building for months.
Families in the suburb had been comparing notes and counting Ewing sarcoma cases connected to their community through Facebook groups and word of mouth. Residents tallied seven cases between 2007 and 2024, including at least one per year starting in 2021, according to resident group Ladera Health Watch. CNN could not independently verify those numbers due to privacy laws.
A troubling question began to take hold in Ladera Ranch: How could so many children connected to the same place develop such a rare cancer?
Ladera Ranch prides itself as an ideal place to raise a family. It was built around a particular vision of childhood: soccer games after school, bicycles left on sidewalks and long afternoons spent in neighborhood parks.
Playing fields and gathering spaces thread through the tidy neighborhoods of the master-planned community, home to around 26,000 people, with pristine roads winding through tree-lined cul-de-sacs.
The same spaces have become the focus of residents’ questions.
Those questions nag at Dustin Matteson, whose 16-year-old son, Brody, was the kind of teenager who seemed to live on playing fields in Ladera Ranch. He spent his childhood cycling through football, rugby, baseball, basketball and soccer, piling up season after season of youth sports.
On the football field, Brody was known as a tough kid. His father, a towering former football player himself, said he discovered just how tough his son was during a brutal 19-month battle with Ewing sarcoma.
Even as cancer spread through his body, Brody kept making plans for the future, worried more about others than himself. “He said, ‘I’m happy it was me and not my brother and sister,’” Dustin recalled, covering his face.
“I always say that football doesn’t build character. It reveals it,” he said. “Brody’s fight with cancer, I really feel the same way. It showed the underlying person that he was.”
Brody died in March at 17. For some residents, his death marked the moment the community’s grief turned into a demand for answers.
Though his family had moved to another state, Brian Dalton flew back in July to join the Mattesons and other parents of children with the rare cancer to call for answers at a Ladera Ranch town hall meeting attended by government representatives, public health authorities and homeowners’ associations.
“I don’t want another father standing where I stand today,” Brian told the room. “Please don’t let Lilly’s story end with her. Let it become the reason we demanded answers.”
As anxiety punctured the tranquility of the suburb, questions bubbled up on everything from the community’s water and pesticide use to abandoned oil wells underneath.
Soon, the questions expanded beyond town halls and Facebook groups, prompting a response from public health agencies, environmental regulators and elected officials.
In July, First Assistant US Attorney Bilal Essayli asked the Environmental Protection Agency to determine whether environmental factors could be contributing to the “unusual cluster of pediatric cancers” in Ladera Ranch and whether any laws had been violated.
It’s not known whether any environmental factors can cause Ewing sarcoma and determining that will take years of sustained research, experts say.
The California Department of Public Health’s cancer registry is now trying to answer a first question: Is there really an unusual number of cancer cases in Ladera Ranch?
Results of the state’s review are expected this fall but the agency cautions that even if it does find the pattern unusual, that review alone cannot determine whether there was an environmental cause for the cancers. For now, the state said it has not identified any “immediate environmental hazards” in the area.
California’s current review of Ladera Ranch follows a 2024 assessment that found no unusual cancer pattern at the county level, though state officials said the available data was limited and did not focus specifically on Ladera Ranch.
“It’s fair for the residents to be concerned that the place that they’re having their kids roll around on and play sports on, and spend most of their life living on, needs to be safe and healthy,” said Orange County Supervisor Katrina Foley, who urged state health officials to expedite their review.
Pesticides and herbicides come under scrutiny
In one of Ladera’s parks this month Brody’s father watched as volunteer researchers fanned out across the grass with shovels and latex gloves. They were collecting soil and water samples into carefully labeled sterile plastic cups, searching for anything unusual lurking there.
Dustin said he hopes the efforts lead to answers.
But even before conclusions can be drawn, Ladera Ranch residents say they had pressured local institutions to begin taking precautionary steps. The community homeowners’ association and the Capistrano Unified School District both paused the use of certain pesticides and herbicides at high-use areas while reviews were underway.
“If there is even a possibility that environmental exposures, including pesticides or any other factor, could be contributing, then those possibilities deserve a thorough, transparent, independent investigation,” Brian said.
The community is part of a national shift toward skepticism of chemicals, pesticides and other environmental exposures. Part of that approach includes not waiting for proof before reducing potential harmful exposures.
The California Department of Public Health makes explicit it is not yet known whether pesticides or other chemicals created an exposure risk in Ladera Ranch.
But because pesticide was a top concern raised by residents, the state officials said their assessment is looking specifically at cancer types linked to pesticide exposure “and asks whether those cancers occur more often in Ladera Ranch than expected.”
The search for answers converged with another local fight already underway.
Months before the cancer diagnoses became a public issue, Creek Team OC, a small grassroots organization, was already campaigning against herbicide spraying in local waterways, arguing chemicals were harming creek ecosystems. After public outcry, Orange County paused herbicide spraying in flood channels countywide while officials evaluate the safest procedures for removing vegetation.
On a sunny August afternoon, the group’s founder, Brent Linas, stood in front of the San Juan Creek, 5 miles from Ladera Ranch, pointing out the lack of plants near the channel.
“There was so much herbicide coming down from this poison creek that nothing could ever grow in here, and no one ever really questioned it,” Linas said. CNN could not independently verify the claims.
It wasn’t until he started calling out local leaders by name on his Instagram account and aggressively demanding answers that real progress was made, Linas said.
When Megan Matteson, whose son Brody had recently died, attended one of the Creek Team’s meetings looking for answers, she brought her notebook of painstaking research on who had what kind of cancer in her community. The group was eager to help.
Pesticides became one of several possible explanations the community felt was worth investigating – and one that quickly gained traction in Ladera Ranch conversations, social media posts, and local meetings.
The community’s homeowner’s association, the Ladera Ranch Maintenance Corporation, told CNN in a statement it became aware of increased resident concern in May and paused certain synthetic landscape maintenance products. At a September 9 meeting, the board approved further reducing synthetic pesticide use across their landscapes and expanded the areas maintained without routine synthetic pesticides.
What’s in a cluster?
Before scientists can determine whether pesticides, drinking water or any other environmental factor may have played a role, experts say they first have to answer a more basic question: Is there actually an unusual number of cancer cases compared to Ladera Ranch’s population size?
The California Department of Public Health told CNN “fewer than 11 cases” of Ewing sarcoma were identified in Ladera Ranch between 1999 and 2023 but said it could not release a more specific count because of confidentiality rules.
“The problem is these cancers are so rare that a community that size really wouldn’t expect to see a case every year, or every several years,” said Joseph Leo Wiemels, director of the PhD Program in Epidemiology at the University of Southern California.
Seven or eight cases of Ewings in a 10-year, or slightly longer period, may sound like a small number, but “it’s more than you would expect based on the community of that size,” he added.
Wiemels is hoping to work on an additional analysis across the whole state to ultimately help assess whether there is anything unusual happening in Ladera Ranch.
But even if researchers determine that cancer rates are unusually high, Wiemels cautions there may never be a definitive explanation.
Residents have been contacting him for months hoping for answers, he said, but proving a particular environmental exposure caused a rare cancer can be extraordinarily difficult.
Wiemels is also skeptical about hastily drawing connections to pesticides.
“I wouldn’t put the blame on pesticides just because it hasn’t shown up as a strong risk factor in other studies on Ewings sarcoma” he said. “If it was a strong risk factor, we would probably see it in other communities that have similar… kind of residential use pesticides.”
Evidence connecting environmental chemicals of any kind to Ewing sarcoma is “very thin,” Wiemels said. Coincidence also remains a possible explanation for an apparent cluster. “It is important to understand that even if pesticide exposure doubled or tripled the incidence of Ewing sarcoma, that is not likely to result in a cluster.”
The epidemiologist pointed to a study of a cluster of childhood leukemia cases in Fallon, Nevada, which suggested a possible infectious link but found no definitive cause for what was behind the unusual pattern – despite millions of dollars investigating the event.
“In general, for cancer, my automatic thought is: ‘What’s in the air that they’re breathing, what’s in the water that they’re drinking, and what’s in the food that they’re eating?’” said Megan Latshaw, professor in Environmental Health and Engineering at the Johns Hopkins Bloomberg School of Public Health.
“Who lives within a certain mile radius of where the wind blows from air toxic emissions? What’s in the toys our kids are playing with, what’s in the building materials in our houses?” she continued. The questions can become maddening, she admits.
But cancer rarely has a single cause. Exposure to a carcinogen can act as a “1-2 punch” for someone who already carries a genetic vulnerability, Latshaw said.
“Cancer takes time,” she said. “A single DNA mutation … you might not even notice that there’s anything going on for years.”
That complexity makes it difficult to isolate any one factor.
While the gene changes that lead to Ewing tumors are known, it’s still not clear what causes these changes.
Unlike with many cancers among adults, which are linked to risk factors like obesity or smoking, there aren’t many known risk factors for most childhood cancers in general.
Still, uncertainty does not necessarily mean inaction. Latshaw said public health officials often rely on the precautionary principle, reducing potential exposures when feasible even before definitive evidence of harm exists.
“It can’t hurt, right?” she said. “Pesticides are toxic. That is why they are invented – to break down some sort of cellular function in a living organism. So, reducing our use of pesticides can be a really good thing, whether or not it was causing an unusual pattern of cancer.”
A community investigates itself
As the community’s questions expanded, a group began pushing for records on anything that may potentially be a cause of cancer in their community, according to Jackie French, one of the organizers of Ladera Health Watch.
They started digging into questions about pesticides and landscaping practices and raised concerns about an abandoned oil well beneath a sidewalk they worried may not have been properly resealed.
The group sent a letter to state officials to evaluate the well’s integrity, and the California Geologic Energy Management Division performed an inspection on August 31, finding no leaks or emissions, a state conservation department spokesperson told CNN.
Residents’ questions about the suburb’s water quality also drew a response from the local utility.
The Santa Margarita Water District, which provides water to Ladera Ranch, said it understands residents’ concerns but noted that more than 30,000 tests are conducted annually and drinking water “meets or surpasses all state and federal regulations.” The utility said it is not aware of any links between drinking water and cancer concerns.
French said residents felt they could not afford to wait indefinitely for official investigations to play out. Parents were already wondering who might be diagnosed next.
“That really hit me,” French said. “We can’t wait. We can’t wait another year for a government agency to come in and try to figure out what’s going on. We have to do it ourselves.”
One of the people who answered that call was Jennifer Piazza, a public health researcher at Cal State Fullerton who also lives in Ladera Ranch.
Concerned for her neighbors and her own family, Piazza assembled a multidisciplinary team of researchers that included chemists, geographers, public health experts, air- and water-pollution specialists and cancer epidemiologists, reflecting the wide range of questions residents were trying to answer.
She was at the park last week as researchers gathered soil and water samples from the suburb to analyze for heavy metals, including lead, arsenic, chromium and pesticide compounds.
The goal, Piazza said, is not to prove a particular theory but to determine whether anything unusual is present.
Two agencies, the Department of Pesticide Regulation and the Orange County Agricultural Commissioner, are also reviewing local pesticide use for any possible violations.
‘It’s a black box’
Early in their efforts, the Ladera Health Watch sought records showing what pesticides had been sprayed, where they had been applied and in what quantities, but many of those details were difficult to obtain before the cases made headlines, French said.
And the work still continues to try to obtain information on pesticide usage amounts, she added.
The group discovered early just how much responsibility for the community’s parks, landscaping and common areas rested with private organizations.
Ladera’s parks and playing fields may feel like public spaces but are controlled by a private homeowners’ association. Ladera Ranch Maintenance Corporation is governed by community representatives and a non-voting general manager.
“It’s a black box,” she said of the system residents encountered while trying to gather information.
The association told CNN that in addition to pausing use of certain synthetic herbicides and plant growth regulators after hearing concerns, the association created a resident advisory committee to review alternatives to routine synthetic pesticide use and remains in contact with county and state officials.
A pilot program – which French said she helped set in motion through external grants – is also looking at organic options for pest and weed control.
Orange County Supervisor Foley said, by default, the government doesn’t have access to records related to pesticide purchases, training materials and other internal documents for communities like Ladera Ranch, and that can be an obstacle.
“There’s an accountability issue as it relates to private HOAs and private contractors because, unlike with public agencies, we don’t have access to their contracts,” Foley said.
“The only way to have access to that is through the investigation process,” Foley said.
Foley said county officials cannot simply ban pesticide use in privately managed communities, since much of the authority to regulate pesticides rests with the state, while investigations into possible violations are handled through separate regulatory processes.
That meant there was no single office, agency or organization capable of addressing residents’ concerns, but a patchwork of agencies where responsibility is fragmented.
For the Daltons and Mattesons, who watched optimism slip into grief after their children endured brutal battles against cancer, the fight now is about getting more information.
“When your child has a rare cancer like that, you don’t feel like you’re just fighting the cancer, you feel like you’re fighting a lack of information about the cancer,” Brian said.
It’s about more than pesticides, water or any single explanation, Brody’s father said.
“We believe that if we can come to figure out what’s causing it, we can address it and move on,” he said.
This month, Brody’s parents and siblings set out to mark his birthday. They got matching tattoos like he had planned to get if he had survived the cancer.
It was their way of honoring the boy who always thought of others first.
As Brian fights to spread awareness about Ewing sarcoma, he said Lilly left him with the request to let everybody know that she didn’t lose her fight with cancer. “It was a draw, because it died with her,” he said.
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