Fire at the world's largest battery plant in California forces evacuations

"There's very little, if any, of a plume emitting from that building," Mendoza said. Crews are not engaging with the fire and are waiting for it to burn out, he said. No injuries have been reported.

But the fallout from the fire at the battery storage facility about 80 miles (130 kilometers) south of San Francisco was just beginning.

"This is more than a fire, this a wake-up call for the industry. If we're going to be moving ahead with sustainable energy, we need to have a safe battery system in place," said Monterey County Supervisor Glenn Church at a briefing on Friday morning.

Battery storage is considered crucial for feeding clean electricity onto the grid when the sun is not shining or the wind is not blowing, and it has been used in significant amounts only in the last couple of years. But the batteries are nearly all lithium, which has a tendency toward "thermal runaway," meaning it can catch fire and burn very hot, releasing toxic gases.

The blaze did not spread beyond the facility, according to Monterey County spokesperson Nicholas Pasculli. As of late Thursday, some local residents were at a temporary evacuation center and the rest had gone to friends or family, Pasculli said. The evacuation orders remained in place as of Friday and residents were advised to close their windows and turn off their air conditioning.

"There's no way to sugar coat it. This is a disaster," Monterey County Supervisor Glenn Church told KSBW-TV.

Brad Watson, Vistra's senior director of community affairs, said the Environmental Protection Agency is testing air quality at the facility and the company has hired an air consultant to check for pollution in nearby communities. Vista will share the results when they are available, Watson said.

Kelsey Scanlon, director of Monterey County's Department of Emergency Management, told reporters that the release of hydrogen fluoride into the atmosphere from the blaze was a cause for concern.

The Centers for Disease Control and Prevention says hydrogen fluoride gas can irritate the eyes, mouth, throat, lungs and nose, and that too much exposure to the gas can be deadly.

Residents expressed concerns about the fire's impact on air quality during an emergency meeting of the Monterey County Board of Supervisors earlier Friday.

"It doesn't appear that the fire department had the appropriate fire retardants to minimize this fire and have to resort to actually letting it burn, exposing all of the residents, including Watsonville in Santa Cruz County, and this is extremely disturbing," resident Silvia Morales said.

Monterey County Sheriff Tina Nieto said none of the air quality monitoring systems had so far detected any hazardous gasses in the air. She said the county was awaiting the arrival of a more advanced monitoring system Friday afternoon before lifting the evacuation order.

Watson said two "overheating events" happened at the battery plant in 2021 and 2022 because the batteries got wet. A third incident happened in 2022 in the neighboring Elkhorn battery plant that is owned by PG&E, he said.

Lithium batteries make the power grid more stable and reduce the need for energy to be generated from fossil fuels, which release planet-warming gases. California was an early adopter of battery storage and leads the nation with more than 11 gigawatt-hours online.

Experts say lithium batteries are a safe technology that are essential for lowering carbon emissions and making grids more reliable. But they are a significant fire risk if they are damaged or overheat.

"We are not convinced that this incident could materially shift the national trend of growing grid scale battery deployment," said Timothy Fox, managing director of ClearView Energy Partners, a non-partisan energy research firm.

It was unclear what caused this latest fire. Vistra said in a statement that after it was detected, everyone at the site was evacuated safely. After the fire is out, an investigation will begin.

"Our top priority is the safety of the community and our personnel, and Vistra deeply appreciates the continued assistance of our local emergency responders," Jenny Lyon, a spokesperson for Vistra, said in a statement.

Jodie Lutkenhaus, professor of chemical engineering at Texas A&M University, said there is a need to find safer batteries that can be used on the grid.

Some improvements, such as more fire prevention measures, can be made to reduce fire risks with lithium batteries, Lutkenhaus said, "but the only way to really address the problem is to use a safer technology." Water-based and redox flow batteries are being developed by scientists but have not yet scaled commercially.