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Current Emergency Information

2025 Moss Landing Vistra Power Plant Fire

Webpage updated 08/11/2026 05:19 PM

Update: Characterization and Screening-Level Risk Evaluation Report Available

Commonly referred to as the Preliminary Environmental Assessment (PEA) Equivalent Report

Prepared by Terraphase Engineering, dated June 22, 2026

State agency partners reviewed the preliminary report and presented their initial findings to the County of Monterey Board of Supervisors on March 17, 2026. Terraphase then prepared the revised report dated June 22, 2026. The County does not expect further revisions.

Report Conclusions

Terraphase concluded that:

  • Chemicals measured in the sampled off-site soil, sediment, and surface water do not indicate lasting conditions expected to pose an unacceptable risk to people or ecological receptors.
  • For purposes of the risk evaluation, Terraphase used conservative, health-protective assumptions and treated measured chemical concentrations as if they were related to the fire.
  • Some nickel concentrations in sediment exceeded ecological screening levels in Hester Marsh and the Mosquito Abatement Observation Area. Terraphase attributed these results to natural variability and marsh conditions rather than lasting fire-related impacts.
  • No further human-health or ecological-risk evaluation, off-site investigation, or response action is warranted at this time for the sampled locations and environmental media.

These conclusions do not apply to conditions within the power plant property, groundwater, unsampled areas, or broader watershed conditions that may be addressed through separate regulatory work.

The report also reviewed air-monitoring and air-sampling data collected by U.S. EPA and CTEH. Terraphase stated that the limited number, generally low magnitude, and short duration of metals-in-air detections above screening levels did not indicate sustained exposure at levels of health concern.

Questions about the report or Terraphase’s conclusions may be submitted to EHB for referral to Terraphase: EHInfo@countyofmonterey.gov

State Agency Review of Report

The following agencies reviewed both the preliminary and revised reports:

Questions about each agency’s comments may be directed to:

U.S. EPA did not participate in the review because its oversight role is focused on on-site battery-removal activities. The County directed the off-site community sampling, and the participating CalEPA agencies reviewed the reports.

What happens next?

Publishing the revised report and state agency comments completes the County’s planned Community Sampling Plan and PEA-equivalent review process.

Completion of this County-directed process does not end other investigations or regulatory work. Separate work may continue regarding:

  • Groundwater;
  • Broader watershed or Elkhorn Slough conditions; and
  • Follow-up recommended or required by state agencies.

Separate work continues within the power plant property

Vistra’s battery removal and the related demolition, treatment, and preparation of batteries for recycling or disposal remain under U.S. Environmental Protection Agency oversight. Information and updates are available through the U.S. EPA Moss Landing Vistra Battery Fire response webpage:  https://www.epa.gov/ca/moss-landing-vistra-battery-fire

Latest News

Update on Toxicologist Data Review and Next Steps

Post Date:07/08/2025 11:21 PM

The County of Monterey pursued a Human Health Risk Assessment (HHRA) related to the Moss Landing battery fire following direction from the Board of Supervisor’s on May 20, 2025.

Early input from these experts indicated that before an HHRA could be meaningfully completed, the first step was to perform a comprehensive review of the existing environmental data for completeness and quality. As a result, the County revised the project scope to focus on this data evaluation phase.

On June 25, 2025, the County received the data evaluation report from Cornerstone Earth Group outlining the results of this review, finding the data is not yet complete to support an HHRA and providing recommendations.

Cornerstone Earth Group, Data Review for Moss Landing Vistra Battery Fire, dated June 25, 2025 

The recommendations make clear that data used for a Human Health Risk Assessment (HHRA) needs a thorough technical analysis, as it should be a complete, high-quality dataset. The Environmental Health Bureau is now taking steps to strengthen and organize the data:

  • Conducting a full quality assurance review of all data included in the County’s public dashboard
  • Incorporating recommendations provided by the toxicologist to improve data organization and completeness
  • Implementing a policy that all new data will be reviewed and quality checked before being added to the dashboard

 

These efforts aim to ensure the county has a full database of reliable information should an HHRA be pursued in the future.

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Timeline of Environmental and Public Health Response 



More Information


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To receive ongoing updates, residents are encouraged to register for alerts at Register | Portal Registration or visit Emergency | County of Monterey, CA. To check your zone, please visit Genasys Protect.


US EPA - Moss Landing Vistra Battery Fire Response


See Yellow Smoke?


Yellowish or brownish smoke can occur during turbine start-ups at the facility. When turbines start, emissions are temporarily higher than during steady operation—similar to starting a car engine. This is a normal, permitted part of facility operations. More information is available here


Concerns or Complaints?


You can submit a report to the Monterey County Health Department's Environmental Health Bureau online at http://www.mtyhd.org/mosslanding-concern-form or by leaving a voice message at 831-755-4505.