RESIDENTS AND LAWMAKERS were expecting to get some answers Tuesday at the Monterey County Board of Supervisors meeting about the consequences of a lithium-ion fueled Battery Energy Storage System fire that ripped through a Moss Landing facility in January 2025, but they left with only questions.
Questions were left unanswered about why scientists hired by the company, Vistra Corp., failed to investigate hundreds of large, black chunks of sediment that were seen deposited in the surrounding area in the days after the fire. Or why the company waited until May to start analyzing impacts, four months after the fire.
Questions remained about why the state’s Department of Toxic Substances Control decided to test soil samples up to 6 inches deep for health impacts, instead of focusing on surface samples, where concentrations of chemical residue might be higher.
And questions were repeated about what, exactly, the immediate impacts were of the fire on the environment and human and animal health.
Scientists with the state Department of Toxic Substances Control were tasked with presenting their own data on human health impacts and a draft report on the environmental impacts was conducted by a consultant firm hired by Vistra, Terraphase Engineering Inc.
But they struggled to answer questions from members of the Board of Supervisors following their presentation, during which they said there would be no long-term impact on the environment, no chronic impact on human health, and no lasting impact on animal life.
Their evaluations contrasted with the findings of a group of scientists based at Moss Landing Marine Laboratories that goes by the acronym EMBER, which stands for Estuary Monitoring of Battery Emissions and Residues.
In its own study, EMBER found higher levels of carcinogenic metals than Vistra’s consultant, Terraphase. EMBER tested more sites, collected samples sooner after the fire, and tested more surface-level concentrations than Terraphase, according to EMBER.
The Monterey County Board of Supervisors is seeking to craft a local ordinance that would potentially prevent a similar fire in the future and dictate terms of cleanup and impact monitoring if one did occur. The findings of the impacts on health and the environment are key to informing that effort.
EMBER scientists did not draw definitive conclusions about the health and ecological impacts of the fire, but blasted the confidence of the findings of Vistra’s consultant and Department of Toxic Substances Control.
Conflicting findings, testing methods questioned
The Department of Toxic Substances Control findings were presented in two parts, one done by a toxicologist with the department, Weiying Jiang, who oversaw a team that collected and analyzed environmental samples to evaluate impacts on human health.
The other part covered ecological impacts on the environment and animal life that was conducted in a report by Terraphase. The state’s role in that report was to review and approve the consultant’s report.
But because it was released in its draft form only three weeks ago and could still be modified, Department of Toxic Substances Control toxicologist Michael Garland said he could not fully evaluate the Terraphase report’s conclusions.
It was that Terraphase report that noted the consultant company had not investigated the large black clumps that had been detected in Hester Marsh, something Supervisor Glenn Church later called “surprising.”
Their origin and composition remains unknown,” Garland said.
He said Terraphase scientists tasked with analyzing environmental impacts had not noticed them on subsequent visits, leading them to believe they had dissolved in rain. He noted they were never tested in a laboratory.
EMBER questioned the Department of Toxic Substances Control’s methods and the time period examined, which EMBER said ignored the days immediately after the fire, and failed to address the need for ongoing monitoring.
The department’s reviews focused on three main components from the batteries: dioxins and furans, metals, and Polycyclic Aromatic Hydrocarbons, which are known as PAHs and sometimes called “forever chemicals” for their inability to break down.
Jiang said the department’s health review had found higher than usual levels of lithium, nickel and manganese in the area around the storage facility, and had detected cobalt and manganese at levels exceeding the safety threshold for children.
But he said those levels were only dangerous if someone stood in the same place for 24 hours and that subsequent tests had not replicated the findings.
The Department of Toxic Substances Control team evaluated air, surface water, soil and pore water, which is the water in sediment. The state team took 108 samples at 27 locations. For soil, the team used samples up to 6 inches deep, which Jiang said was appropriate to test for long term “chronic health risks.”
But Church would later ask, without an answer, why the team had dug so deep, as that would presumably give different results than more immediate impacts from shallower samples.
EMBER’s group found much more elevated levels of cobalt, manganese and nickel in soil samples 1-5 mm deep, one of the group’s scientists, Kerstin Wasson said.
“So, taking a few deep cores are not well suited to detecting a thin, patchy layer of battery metals on the soil surface,” Wasson told the Board of Supervisors. “And the cores collected that you just heard about that were taken in September by Terraphase were taken far too late to detect this fallout layer.”
She said the study of impacts was nowhere near its conclusion and said bioaccumulation in plants and animal species can take time. She urged continued monitoring of ecological impacts, including those on plants, mollusks, crustaceans and fish.
“Claims of the absence of ecological impacts are premature at best and misleading at worst,” Wasson said.
Frustration, distrust deepen
Ed Mitchell, a local resident and member of the citizens’ advocacy group Never Again Moss Landing, told the Board the group had no faith in Vistra’s or the state monitors’ efforts to find out what the real impacts were.
“A measurement is only as good as the method used,” he said. “Plus, if you don’t want to find something, and you don’t look for it, you won’t find it.”
He said the ignition, the thermal runaway that caused the batteries to catch fire, and the composition of the fire itself still had not been adequately evaluated.
“They aren’t seeking answers, they’re seeking an exit strategy,” he said.
Angry and frustrated residents reiterated during public comments how they and their neighbors suffered respiratory problems, bloody noses, and generational terror that had caused older residents to move and an exasperated mother left wondering what the impacts to her baby were.
Church, who represents Moss Landing on the county Board of Supervisors, recalled a constituent who had gone to the emergency room twice in the weeks after the fire. He said he was “shocked” by the lack of answers, including information on immediate impacts, rather than chronic or long-term ones, the methodology used, and the difference in the findings between EMBER and the company’s consultant.
Supervisor Wendy Root Askew said it was “frustrating we can’t get the answers we’re looking for.”
Supervisor Kate Daniels called on the company to fund continuing monitoring of the impacts in a working group that would include EMBER and inquired how the Board of Supervisors could potentially compel Vistra to do so if it declined.