When fire broke out at the world’s largest battery energy storage facility in January 2025, its thick smoke blanketed surrounding wetlands, farms and nearby communities on the central California coast.

Highways closed, residents evacuated and firefighters could do little but watch as debris and ash rained down. People living in the area reported headaches and respiratory problems, and some pets and livestock fell ill.

Two days later, officials announced that the air quality met federal safety standards. But the initial all-clear decision missed something important – heavy metal fallout on the ground.

When battery energy storage facilities burn, the makeup of the chemical fallout can be a mystery for surrounding communities. Yet, these batteries often contain metals that are toxic to humans and wildlife.

The smoke plume from the fire in Vistra’s battery energy storage facility at Moss Landing released not just hazardous gases such as hydrogen fluoride but also soot and charred fragments of burned batteries that landed for miles around.

I am a marine geologist who has been tracking soil changes in marshes adjacent to the Vistra facility for over a decade as part of a wetland-restoration project. In a new study published in the journal Scientific Reports, my colleagues and I were able to show through detailed before-and-after samples........

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