Scientists Trace Heavy Metals Spread by January’s Huge Battery Fire Near Monterey

After a thermal runaway set the world’s largest battery storage facility on fire last winter near Monterey, Ivano Aiello and his colleagues at San José State University had some detective work to do.

The fire, which broke out at the Vistra Energy Storage Facility in Moss Landing on Jan. 16, burned for days, producing a plume of black smoke that was visible for miles.

“There was obvious debris related to the fire pretty much all over the place, so it was evidence that something came out from the smoke plume,” said Aiello, a professor and chair at Moss Landing Marine Laboratories.

To understand exactly what the fire spread, Aiello and his colleagues began to investigate. Their results, published in the journal Scientific Reports, were released Monday.

When the fire broke out, they had already been collecting soil samples from nearby Elkhorn Slough, a sanctuary for endangered wildlife, so they had baseline data for comparison. After the fire, they tested for nickel, manganese and cobalt — the primary elements used in lithium-ion batteries.

Using a powerful electron microscope, they saw tiny beads of those metals in the soil. “That was pretty much a smoking gun,” Aiello said.

Concentrations of the metals were between 10 and 1,000 times greater than they had been before the fire.

They also found that the correlation of nickel to cobalt followed a strict 2:1 ratio — the same proportion used in manufacturing the batteries at the Vistra facility.

“Now we are using that fingerprint to trace how those metals are moving through the environment,” Aiello said.

Preliminary test results from another team of San José State scientists give some indication that the metals, which can be toxic above certain concentrations, have entered the food chain in the nearby estuary.

But the concern is not only for the local wildlife, which includes the southern sea otter, a threatened species still struggling back from the brink of extinction. Many agricultural fields are also close to the Moss Landing battery plant.

And, there’s another piece of detective work still to be done. Aiello and his colleagues calculated that the heavy metals they found in the soil amounted to less than 2% of the metals contained in the burned batteries.

“Where is the other 98%?” Aiello said. “Some of it might have gone straight to the ocean, but some of it might have traveled elsewhere because those particles are very, very tiny.”

Vistra Corporation, which operates the Moss Landing battery plant, said in a statement that a different study conducted in October showed heavy metals found in soil near the battery plant were mostly within approved levels, and not necessarily related to the fire.

“The safety of our employees, the environment, and the surrounding community remains our top priority,” said Jenny Lyon, a spokesperson for Vistra. “We will continue to work closely with local officials and community partners in the Moss Landing community.”

Aiello hopes that as electric energy becomes more common, his work will help create a different approach to how we go about setting up battery storage facilities: “Maybe we can think better when we locate some of those storage facilities, which have the potential to contaminate soils and also the food.”