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Current Emergency Information

2025 Moss Landing Vistra Power Plant Fire

Webpage updated 09/03/2026 03:19 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

Battery Disconnection Process to Begin at Moss Landing Site to Reduce Risk of Reignition

Post Date:02/21/2025 3:43 PM

The disconnection process for the remaining lithium-ion batteries at the 300-MW Phase I Moss Landing Energy Storage Facility will begin on Saturday, February 22, 2025.

Vistra’s independent contractor will begin delinking the racks of lithium-ion batteries in the Moss 300 building where the January 16 fire and February 18 reignition occurred. Since the initial fire, Vistra has been working in consultation with U.S. EPA on developing procedures to isolate the batteries safely and efficiently since the damaged batteries pose a potential fire and health risk. The North County Fire Protection District will also review these plans.

Because not all the batteries were consumed in the fires, the remaining individual battery modules in the building must be disconnected and isolated from one another to mitigate the risk of thermal runaway and fire. Thermal runaway occurs when a battery begins to heat up uncontrollably. Given the damage at the facility, if thermal runaway occurs this chemical chain reaction could not be stopped, and energy stored inside the connected batteries could feed the reaction, which poses a significant risk of ignition and propagation into adjacent batteries.

The first phase of the delinking process includes approximately one third of the remaining individual battery modules. U.S. EPA and Vistra are taking all necessary precautions to prepare for and prevent an incident throughout the delinking process and estimate the first phase will be complete in approximately two weeks. The remaining batteries are in areas of the building that are not currently safe to enter, therefore, once the demolition of the damaged building near the remaining batteries is complete, the rest of the batteries will be delinked.

 

The North County Fire Protection District has been in communication with Vistra and U.S. EPA since the initial fire and will be the first responding agency should another flare-up occur. Vistra has also engaged a private fire brigade that is on site 24/7 to provide additional support. Air monitoring at the site is continuous, as Vistra has an air monitoring network with sensors in and around the facility. The Monterey Bay Air Resources District also maintains a fine particulate matter air sensor network in the Monterey Bay area.

 

U.S. EPA issued a Notice of Federal Response Action to Vistra, the responsible party. Vistra has been cooperating voluntarily to implement the response actions that U.S. EPA indicated are necessary. Thus far, U.S. EPA has tasked Vistra to develop additional health and safety plans for on-site actions, emergency response plans, and operations procedures to reduce the threat of releases on-site.

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Timeline of Environmental and Public Health Response 

More Information

Stay Informed

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.