Archive · 31 Aug 2026
Abandoned California Well Raises Questions About Cancer Cluster
People in Ladera Ranch are worried because six children developed a rare cancer over 11 years.
Some adults and pets in the area have also reportedly had cancer.
Residents wonder whether pesticides, herbicides, a landfill, or an old oil well might be involved.
The well was sealed in 2002, before homes were built in the area.
A handwritten note on an official permit warned against building over it without more consideration.
Officials do not know exactly why the warning was written.
The state said the note might have been a clerical mistake.
Scientists have not found proof that the well caused the cancer cases.
They also say there is no known environmental or lifestyle cause for Ewing sarcoma.
Residents and researchers say the old warning should still be investigated.
Six Ladera Ranch children were diagnosed with rare Ewing sarcoma between 2013 and 2024.
Residents suspect pesticides, herbicides, a landfill, or the abandoned well may be linked to cancer cases.
A 2002 permit contained handwritten warnings not to build over the well without further consideration.
Officials said the notes may reflect a clerical error, while one supervisor could not recall why they were written.
Experts say there is no proof connecting the well to the cancers and no scientific consensus on what causes Ewing sarcoma.
- Who
- Six children in Ladera Ranch, local residents, state officials, and environmental-health researchers are involved in the discussion.
- What
- Residents are investigating whether an abandoned oil well or other environmental factors could be connected to a cluster of Ewing sarcoma cases.
- When
- The well was sealed on February 26, 2002; the six reported cancer cases occurred between 2013 and 2024.
- Where
- Ladera Ranch in Orange County, Southern California.
- Why
- Residents are concerned because multiple children, adults, and pets reportedly have cancer, while old permit notes warned against building over the well.
Residents and Investigators
Officials and Scientific Authorities
Possible cause of the cancer cases
Residents and Investigators
Residents suspect pesticides, herbicides, a landfill, or the abandoned well may be contributing to cancer among children, adults, and pets.
Officials and Scientific Authorities
The American Cancer Society says no known lifestyle-related or environmental causes have been identified, and there is no proof that the well caused the Ewing sarcoma cases.
Meaning of the handwritten warning
Residents and Investigators
Residents and environmental-health researchers say the warning should be examined to determine whether concerns about the well were resolved before construction.
Officials and Scientific Authorities
The Department of Conservation said the note could have been a clerical error, and a former supervisor could not recall why the warning was issued.
Whether the well may have posed a hazard
Residents and Investigators
Researchers say the concern could have involved the well’s condition, sealing method, sealing materials, or possible movement of gases or other substances.
Officials and Scientific Authorities
The available notes do not establish that the well was hazardous, and officials have not identified a confirmed connection to the cancer cases.
- Location
- Ladera Ranch, Orange County, California
- Cancer cases
- Six children diagnosed with Ewing sarcoma
- Case period
- 2013–2024
- Well status
- Abandoned and sealed on February 26, 2002
- Permit warning
- A handwritten note said the well should not be built over without further consideration.
- Possible explanations raised
- Pesticides, herbicides, a landfill, and the abandoned well
- Scientific evidence
- No proof currently connects the well to the cancer cases.
- Official explanation
- The California Department of Conservation said the notes could have been a clerical error.