Current Emergency Information
2025 Moss Landing Vistra Power Plant Fire
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:
- California Department of Toxic Substances Control, or DTSC
- California Office of Environmental Health Hazard Assessment, or OEHHA
- Central Coast Regional Water Quality Control Board Attachment A
Questions about each agency’s comments may be directed to:
- DTSC: Yang Dong, Project Manager Yang.Dong@dtsc.ca.gov
- OEHHA: Amanda Palumbo, Staff Toxicologist amanda.palumbo@oehha.ca.gov
- Central Coast Water Board: Greg Bishop, Supervising Engineering Geologist greg.bishop@waterboards.ca.gov
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
Public Update: Environmental Assessment Report for Moss Landing Power Plant Site Completed
The County-directed environmental review of off-site community sampling is now complete. The Monterey County Environmental Health Bureau has compiled the available testing data, technical reports, and state agency comments for public review.
Available Online:
- Written comments from:
What the Report Says
- Terraphase concluded that sampled off-site soil, sediment, and surface water did not show conditions expected to pose an unacceptable long-term human-health risk.
- State agency comments did not challenge that long-term human-health conclusion, but identified other technical issues, differing interpretations, and remaining data gaps.
- Terraphase did not recommend additional investigation, remediation, or other response action for the specific sampled locations and environmental media.
- These conclusions are limited to the sampled locations and environmental media evaluated in the report.
What Remains
- This report completes the County’s off-site community sampling and review effort.
- Questions remain about exposure during or immediately after the fire, broader watershed movement, long-term biological effects, and future monitoring.
- Separate Central Coast Water Board orders address groundwater, aerial deposition, watershed transport, and related pathways.
- Any further work will occur through separate regulatory, research, or policy processes. The report’s data may help inform those efforts.
Understanding the County’s Role
The EHB acted as an independent coordinator to ensure a transparent public process. Please note the following boundaries regarding our authority:
- Coordination: We organized off-site community testing and brought state agency partners together.
- No Independent Review: We did not author the report, independently verify the technical data, or officially adopt the conclusions.
- Future Actions: Any future environmental cleanup, water monitoring, or regulatory decisions will be handled directly by the state agencies holding legal authority over these matters.
Have Questions?
If you have questions about the report's data, testing methods, or conclusions, please contact the reviewing state agencies or email the County directly at EHinfo@countyofmonterey.gov.
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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.
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