Archives that may still hold the record

Where a vat could still be named, and how you can help.

California never logged where its arsenic dipping vats stood. That single missing fact, the exact location of a vat on this land, is the one thing the public paper trail cannot yet close. The records that could still name one are most likely sitting in a small number of collections that have not been fully searched. Records requests have been drafted but not yet pulled.

If you work at, volunteer with, or simply have access to any of the collections below, you can help. A single ledger page, ranch map, veterinarian order, or vat-count entry could move this forward. Please reach out through the contact form. Every lead is checked, sourced, and credited, and nothing here assumes what those records will show.

• Sherman Library, Corona del Mar. O'Neill and Irvine Ranch business records, ledgers, and photo albums.
• UCI Special Collections, Irvine. Ranch collections and oral histories.
• Rancho Mission Viejo archive. The private corporate ranch records, 1900 to 1920.
• Orange County Archives, Santa Ana. County Veterinarian orders and Board of Supervisors minutes, 1907 to 1913.
• California State Archives, Sacramento. Department of Agriculture cattle-protection vat-count files.
• San Juan Capistrano Historical Society. Local ranch photographs and records.
• Camp Pendleton Historical Society. Santa Margarita ranch (O'Neill) holdings.
• Starr Ranch Sanctuary (Audubon), Bell Canyon. The one documented dip ground in the study area.
• The Huntington Library, San Marino. Historic ranch maps and aerials.
• USC and UCLA Special Collections. Historic Southern California ranch photography.

The drafted requests are public, so anyone can pick up a thread: research/archives/RECORDS_REQUESTS_2026-07.md. If you can add a collection, correct a holding, or share a document, it becomes part of the report, with credit. This is an independent research project; it asks only for records and makes no claim about what any of them will contain.