Investigators Find Arcing on an Out-of-Service Edison Tower Caused the Eaton Fire

The Eaton fire, which killed 19 people and destroyed or damaged more than 9,000 homes and businesses in the Altadena area in January 2025, was caused by electrical arcing on an out-of-service Southern California Edison transmission tower, according to investigative reports released by the Los Angeles County Fire Department on August 4, 2026. The investigation was conducted jointly with CAL FIRE over 18 months, with retained electrical and metallurgical experts. The reports found that the fire originated in dry vegetation below SCE transmission towers on a spur ridge above Eaton Wash.

"While the cause has been determined, our focus remains on assisting our residents to rebuild their homes and livelihoods, and ensuring lessons learned drive meaningful and impactful change in memory of the 19 lives lost," said Fire Chief Anthony C. Marrone. The county said the reports were redacted because the Los Angeles County District Attorney's Office is conducting an ongoing review of the evidence. The Eaton fire started on the evening of January 7, 2025, during an extreme Santa Ana wind event.

Under California's doctrine of inverse condemnation, a utility can be held liable for property damage caused by its equipment even if it was not negligent. In response, California created a wildfire fund in 2019, financed by utility shareholders and customers, to pay eligible claims above a threshold and protect utilities from insolvency. The cause finding is a key step in determining SCE's liability, though it does not by itself settle questions of negligence or the prudence review that determines how much SCE must reimburse the fund.

The finding that the fire started on idle equipment raises questions about utility practices for decommissioning and maintaining unused lines. Wildfire risk in California and across the western United States has grown with hotter temperatures, longer dry seasons and the expansion of homes into fire-prone areas. For energy markets, wildfire risk affects utility credit ratings, cost of capital and the ability to finance grid investment needed for growing demand, including from data centers and electrification.