The full picture
What we know. What we don't.
We are asking reasonable questions and requesting reasonable changes, not making claims we can't support. This page lays out, as plainly as we can, the difference between what has been documented and what remains genuinely unknown.
What we know
- Self-reported Ewing sarcoma diagnoses in Ladera Ranch children across 2007, 2013, 2017, 2021, 2022, 2023, and 2024
- Additional self-reported cancer cases among Ladera Ranch residents and pets
- Regular pesticide, herbicide, and rodenticide applications in common areas, documented in LARMAC notices
- CUSD records show the product Cheetah Pro (glufosinate-ammonium) was applied at several Ladera Ranch school sites in 2026
- A California Cancer Registry analysis was formally requested in May 2026; results are pending
- On July 8, 2026, LARMAC agreed to form a resident advisory committee on Integrated Pest Management
What we don't know
- Whether cancer rates in Ladera Ranch exceed state baselines
- What caused any individual case, including the ones reported here
- Whether any environmental factor (pesticides, herbicides, rodenticides, water, or something else) is involved
- Whether the number or timing of cases reported here is statistically unusual for a community this size
No cancer cluster has been officially determined in Ladera Ranch. Formal cancer cluster findings are rare, even in communities that pursue them for years, per CDC/ATSDR guidelines.
Common questions
Is there a cancer cluster in Ladera Ranch?
No cancer cluster has been officially determined in Ladera Ranch. Formal cancer cluster findings are rare, even in communities that pursue them for years, per CDC/ATSDR guidelines.
What caused the cancer cases reported in Ladera Ranch?
We do not know. Ladera Health Watch has not identified a cause for any individual case, and no formal cause has been determined.
Does pesticide or herbicide use cause Ewing sarcoma?
There is no known environmental cause of Ewing sarcoma, according to the American Cancer Society. Ladera Health Watch is not claiming that pesticides, herbicides, or any other product or practice has caused any cancer. Environmental records are simply a practical place to start asking questions.
Are cancer rates in Ladera Ranch higher than the rest of California?
We do not yet have confirmation that cancer rates in Ladera Ranch exceed California's state baseline. Ladera Health Watch has requested a formal analysis from the California Cancer Registry to help answer this question.
Timeline of the effort
May 2026
Requested a formal analysis from the California Cancer Registry
Result: pending. We will publish whatever the registry finds.
May–June 2026
Filed public records requests with LARMAC and CUSD
Requesting pesticide, herbicide, and rodenticide application records for common areas and school sites.
July 8, 2026
Raised these questions at the LARMAC board meeting
A constructive conversation with the board, who are resident volunteers like us.
Ongoing
Resident advisory committee on Integrated Pest Management is forming
See News & Updates for how to get involved as it stands up.
A note on environmental cause
There is no known environmental cause of Ewing sarcoma, according to the American Cancer Society. Several experts have told us this is worth looking into, and that environmental records, especially water and pesticide/herbicide use, are the practical place to start. That's why our records requests focus there. It is not a claim that any product or practice has caused any cancer.
Reading pesticide notices
LARMAC posts notices before applying pesticides, herbicides, and rodenticides in common areas. Here's a plain-language guide to what those notices say, so residents can read them with confidence. This isn't a claim that any specific product is dangerous.
Product
The brand name and usually the active ingredient. Look up either one; see below.
Location
Which common area or landscaping zone the application covers.
Date
The application date, and often a posting date in advance of it.
Many notices mention a "restricted entry interval" (REI): standard, required label language stating how long to wait after an application before re-entering the treated area without protective equipment. It's routine on pesticide labels generally, not something specific to Ladera Ranch or to any one incident.
- Official notices: LARMAC posts its IPM (Integrated Pest Management) and spray notices at laderalife.com ↗.(TODO: confirm this is the current path.)
- Product labels and safety data sheets: search the product name plus "safety data sheet" (SDS, or older, "MSDS") for the manufacturer's own label, ingredients, and handling guidance.
Community Map
We're building a map showing aggregated, anonymized case counts, never individual homes or identifiable cases. An aggregate map is coming soon.