A Jan. 16 battery fire in Moss Landing has prompted health and environmental concerns. (Nik Altenberg — Santa Cruz Local file)
MOSS LANDING >> This week, scientists collected another round of soil samples in north Monterey County to determine whether January’s Moss Landing battery fire left lasting contamination.
Soil tainted with heavy metals like manganese and other contaminants associated with lithium battery fires can track into homes and cause serious health issues such as cancer and neurological problems, scientists have said.
County and state officials said tests so far haven’t pointed towards health risks, but a UC Santa Cruz scientist and some residents want more comprehensive tests to address health concerns.
Residents are “not getting the answers, and they feel like they’re being told there’s not a problem. But nobody can really demonstrate clearly that there’s not a problem,” said UCSC environmental toxicologist Don Smith.
In the wake of the Jan. 16 fire at a battery storage facility at the Moss Landing power plant, state legislators have proposed new rules for the location and design of battery storage facilities. The facilities are key to the state’s plan to transition from fossil fuels.
But there are no standards for environmental or human tests after such a fire, and no legislation in the works to create any.
Piecemeal testing after the fire
The blaze produced plumes of black smoke then smoldered for weeks and reignited in February. Firefighters said they could not douse the flames with water because of the batteries’ chemical composition.
Many agricultural fields and waterways surround Moss Landing, and some residents and scientists worried that ash carried in the wind may have contaminated the soil and water.
In late January, the California Department of Toxic Substances Control and Monterey County environmental health authorities tested soil at seven sites. The results didn’t indicate a threat to human health, said Marni Flagg, assistant director of Environmental Health for Monterey County. But, “I definitely wouldn’t sound a total all-clear,” she said.
If heavy metals or other contaminants have been deposited into soils, they could be continuously ingested or inhaled as dust is kicked up and tracked into homes, raising the risk of chronic exposure, Smith said.
A plan for soil samples collected this month includes 27 sites in Monterey County. (California Department of Toxic Substances Control)
This month, state regulators began overseeing more comprehensive tests of soil samples within 10 miles of the fire. Battery facility leaders at Vistra Corp. hired Terraphase Engineering Inc. to collect 27 soil samples across northern Monterey County, including in Las Lomas, Royal Oaks and Moss Landing.
Scientists from DTSC oversaw the sampling and collected their own samples at about half of the sites, a DTSC spokesperson said. The side-by-side sampling is intended to help the community trust that Terraphase accurately collects and analyzes samples, Flagg said.
DTSC and Terraphase plan to separately test their samples for heavy metals and other harmful chemicals such as dioxins. Although metals like manganese and cobalt are micronutrients, high levels can be toxic. Manganese can cause ADHD and developmental delays in children, and symptoms similar to Parkinson’s in older adults, Smith said.
Dioxins can lead to serious health conditions like cancer and fertility problems, according to the U.S. Environmental Protection Agency.
Results are expected on Monterey County’s website by the end of May. State and local officials will then decide if further testing is needed.
None of the sites for sampling are within Santa Cruz County. Following the fire, Santa Cruz County staff collected soil and plant samples at farms in south Santa Cruz County, and water samples at Drew Lake, Kelly Lake, Pinto Lake and Watsonville Slough.
The “metal levels detected in Santa Cruz County are significantly lower than samples collected in Monterey County closer to the Moss Landing site and do not suggest elevated public health risks or food safety concerns,” Santa Cruz County spokesperson Jason Hoppin wrote in a Feb. 21 statement. No further testing in the county is planned, he said.
Community concerns
The community group Never Again Moss Landing has conducted its own tests. Following a resident-led effort to collect scores of samples of outside surface dust, the group commissioned a more formal sampling effort for 16 sites in January, and again after a flareup in February. In some areas, heavy metals were detected both times, said Brian Roeder, co-founder of the group.
Signs that oppose a proposed lithium battery facility are scattered in and around Watsonville, including on Corralitos Road near Freedom Boulevard. (Nik Altenberg — Santa Cruz Local file)
A UC Davis laboratory is developing a proposal to analyze blood samples from livestock and pets near Royal Oaks, Roeder said. National environmental justice groups also have expressed interest in conducting their own tests, he added.
Many residents in the area have reported physical symptoms following the fire. Flagg said “there weren’t very many alarming results” from the samples collected by Never Again Moss Landing.
But Smith, the Santa Cruz environmental toxicologist, said the levels of manganese, cobalt and nickel in some samples “are sufficiently high to raise, in my opinion, cause for concern for adverse health effects,” he said. Vistra should pay for more comprehensive testing, he said, including indoor dust samples and residents’ blood, urine and hair.
A Vistra representative did not respond to requests for comment.
Without human samples, “it’s impossible to say whether the levels in their environment, even if they are elevated above background levels, are translating into an increased exposure that would put them at risk,” Smith said.
DTSC doesn’t plan to collect dust samples or require Vistra to do so because there aren’t standards for safe exposure levels in household dust, an agency spokesperson wrote. Monterey County public health has consulted with the California Department of Public Health, and has no plans for collecting human samples, a county spokesperson said.
One challenge in assessing soil and water samples is distinguishing possible recent contamination from pesticide residue or other pollution. Oil stored at the Moss Landing power plant before 1995 contaminated the soil and groundwater with petroleum and other chemicals, according to state records.
Advice for residents
UCSC environmental toxicologist Don Smith advised residents near Moss Landing to:
- Avoid tracking outdoor dust inside.
- Keep homes free of dust.
- Use a vacuum with a HEPA-certified filter.
- Consider wearing a mask while cleaning or dusting.
Marni Flagg, assistant director of Environmental Health for Monterey County, advised people near Moss Landing to resume normal outside activities like gardening, but “I wouldn’t necessarily recommend kicking up a lot of dust in those outside activities until we put everything to rest,” she said. Residents with lingering health effects should consult a doctor, she said.
However, samples of marsh soil from Elkhorn Slough collected before and after the fire show levels of some heavy metal nanoparticles hundreds or thousands of times higher, researchers from San José State University’s Moss Landing Marine Laboratories said. Smith said those results indicate that the battery fire caused the contamination.
State legislation
State legislation has been proposed to tighten regulations for the siting and design of battery power plants. But there are no laws or proposed legislation about how much testing must be done following a battery fire. State Sen. John Laird, D-Santa Cruz, said he has pushed DTSC to continue testing.
After the results from samples collected in January, the agency “didn’t feel the urgency in testing,” Laird said. “I was advocating for the fact that there’s community concern, there could be some changing circumstances. It’s very important to do regular testing until people feel like we’re out of the woods,” Laird said.
Cheri Garcia, who works across the street from the power plant, said some residents with concerns have felt sidelined. Garcia spoke at a March meeting of Never Again Moss Landing,
“People are really scared because they feel like no one is listening to them,” Garcia said. “This is real for us. We have real symptoms.”
Read more
- Lithium battery proposal near Watsonville faces hurdles — March 27, 2025
- Residents told to monitor smoke from Moss Landing fire — Jan. 17, 2025
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Jesse Kathan is a staff reporter for Santa Cruz Local through the California Local News Fellowship. They hold a master's degree in science communications from UC Santa Cruz.
