After Toxic Monterey Battery Fire, These Scientists Watch Over a Fragile Ecosystem

A fluffy otter pup floats alone on the surface of Elkhorn Slough, waiting for its mother to return from a dive. It squeals in agitation, then quiets as she surfaces, holding a fat innkeeper worm in each paw.

The worms “basically just look like a giant hotdog,” said Isabella Rose, a naturalist with the Elkhorn Slough Safari boat tour operator. “And the otters really like to eat them.”

The southern sea otter is one of 16 threatened and endangered species that make their home in the slough, a protected wetland in the center of the Monterey Bay coast. It’s right next to the site where, last month, a 100-foot plume of fire destroyed one of the biggest battery storage sites in the world.

The cause of the fire at the Vistra Energy Storage Facility is still unknown. And so are its consequences for the sensitive ecosystem.

Ivano Aiello, professor and chair at Moss Landing Marine Labs, has found nanoparticles of manganese, cobalt and nickel in the soil of Elkhorn Slough, in some locations at levels 1,000 times greater than before the fire.

“They weren’t there [before],” said Aiello, who has been monitoring the soil at the slough for over a decade. “It’s that simple. I’ve never measured those metals in such high concentrations.”

Aiello is now working with a team of scientists to check whether the heavy metals, found in the lithium-ion batteries that burned, are moving through the tidal ecosystem.

“Some of it might actually move through the soil as the water percolates,” he said, “and potentially enter the food web.”

The animals in Elkhorn Slough have so far shown no changes in behavior or numbers. But scientists are monitoring to see whether the metals, for example, could make their way into those fat innkeeper worms, which feed at the bottom of the slough. And from there, into the otters.

Professor Dustin Mulvaney of San José State University, who researches the environmental impacts of batteries, pointed out that the heavy metals might also affect the local Amah Mutsun tribe, who have restored oysters to Elkhorn Slough.

“One concern I would have is for the Amah Mutsun,” Mulvaney said, “if they’re going to be eating those Olympia oysters at some point.”

A group of Moss Landing residents is suing three energy companies — Vistra Corp., which runs the facility, PG&E, which draws power from it, and LG Energy Solution, which installed the batteries — saying they experienced dizziness, skin irritation and other health symptoms after the fire. They say the Texas-based Vistra should have taken better safety precautions in the energy storage facility, which is somewhat of an outlier in that it was built inside an old gas power plant and the type of battery it used is becoming less common.

Vistra declined a request for an interview but said in a statement that it’s monitoring the air and that no hazardous levels have been detected.

The California Public Utilities Commission is investigating the cause of the fire and has issued new proposed safety standards for battery storage facilities.

“Batteries and fires have been a known issue,” Mulvaney said. “Our regulation and our ability to think through the impacts of new technology are sometimes a little bit behind the technology itself.”

Aiello and other scientists are continuing to collect and analyze samples from Elkhorn Slough and release data as it becomes available.

”We need to learn as much as possible,” Aiello said. “It’s an opportunity for society to learn more about whether this type of technology is the way we want to go.”