Newly resurfaced notes from the developer behind an affluent California community have renewed scrutiny over what may be driving an unusual cluster of rare childhood cancer cases in the area.
Ladera Ranch, a well-heeled master-planned community of roughly 25,000 residents east of Laguna Beach, has recorded at least six confirmed cases of Ewing sarcoma from 2013 through 2024.
Ewing sarcoma is an exceptionally rare and painful cancer diagnosed in only about 200 people in the US each year. It most often strikes children and teenagers, developing in bone or soft tissue, and if it is not detected early, the survival rate is about 30 percent.
For years, parents in Ladera Ranch who have lost children to the disease have searched for answers, trying to understand why such a rare cancer appears to have surfaced so often in their community.
Residents have pointed to several possible explanations, including extensive pesticide use in the area and the presence of a nearby landfill. But handwritten notes found in the archives of Ladera Ranch’s development company, DMB Development, have prompted fresh concern.
The notes, believed to have been written in the early 2000s while Ladera Ranch was being built, state: “This well is not to be built over without further considerations.”
In 2002, DMB Development re-sealed two abandoned oil wells so they would comply with modern safety standards. The warning was handwritten on a Department of Conservation permit and also appears in typed form in the final well-abandonment report.
The wells had no record of producing oil or gas, and there is currently no evidence linking them in any way to the Ewing sarcoma cases reported in Ladera Ranch.
In Ladera Beach, California, there have been an unusually high number of cases of Ewing sarcoma, an incredibly rare form of cancer, between 2013 and 2024
Handwritten notes in the files of Ladera Beach’s developer have raised fresh questions about the cause of the rare cancer cases
Lily Dalton, a resident of Ladera Ranch, died aged 23 from Ewing sarcoma. She is one of at least six people to have contracted the extremely rare form of cancer in the community since 2013
The Department of Conservation told the Los Angeles Times that the note’s presence in the final report may have been a ‘clerical error.’
However, one of the handwritten notes also said ‘put on final letter.’ The Department of Conservation did not comment on that message when the Times asked about it.
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The notes do not explain why construction should potentially be avoided on top of the wells, and it is unclear whether there was any ‘further consideration.’
The presence of the notes in DMB Development’s files raises more questions than answers for Ladera Ranch residents who have been demanding investigations into potential causes for Ewing sarcoma cases in their community.
Bonnie Regan, whose son Ryan died aged 36 in October 2025 from Ewing sarcoma, told the LA Times: ‘There’s something wrong here. I had never even heard of this kind of cancer before.’
Brian Dalton, who lost his 23-year-old daughter Lily to the disease in January, told the California Post he suspects pesticides caused her cancer but said he wants a broader investigation.
‘When something this unusual happens, families deserve answers,’ Dalton told the outlet.
‘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,’ he added.
Lily is pictured partway through her cancer treatment. Her father demanded an investigation into Ladera Ranch’s environment after she died
Brody Matteson (center back) died from Ewing Sarcoma at the age of 17 in March. His father said he wants to find out what caused his son to fall ill
Dustin Matteson, whose 17-year-old son Brody died from Ewing sarcoma in March, told the Times: ‘It feels like where we live, and with the high number of cases, it’s a place where you should be able to find out what caused it.’
Despite the lack of any tangible connection between the sealed wells or other theories about the cause of Ewing sarcoma cases in Ladera Ranch, experts say that grieving families are right to be asking questions, though they have also cautioned against jumping to conclusions.
Karen Lincoln, director of the Center for Environmental Health Disparities Research at UC Irvine, told the California Post: ‘We don’t know that the well is causing harm.
‘But residents are telling us they are concerned about a potential environmental health risk. They deserve a serious, transparent response.’
Dr Janet Yoon, a pediatric hematologist-oncologist at City of Hope who specializes in Ewing sarcoma, told the LA Times that it would be ‘incredibly challenging’ to prove a link between the cases in Ladera Ranch.
But she did say that the number of cases in the community appeared unusually high and said: ‘There definitely is cause for concern for members of this community.’
