EPA and Vistra near agreement to remove burned Moss Landing battery modules; county says sampling and risk analysis will continue

Federal and private agencies are moving toward a legally binding order to remove burned lithium-ion battery modules and structural debris from the July 16, 2025, fire at Vistra Energy's Moss Landing 300 MWh battery facility, Monterey County officials said during a July 8 board briefing.

The U.S. Environmental Protection Agency (EPA) and Vistra have been negotiating an administrative settlement agreement and order on consent (ASAOC) under federal CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act) authorities that will require Vistra and its subsidiaries to perform and pay for the battery-debris removal. The county expects that the ASAOC will be executed in the coming weeks; EPA and contractor VISTA (Vistra's response contractor) have been finalizing plans, procedures and contracts for module removal, off-site transport and disposal.

Scope and sorting protocol: County presenters said the ML300 building contained 98 racks and nearly 100,000 battery modules with a total palletized battery weight of about 19.6 million pounds (19,572,168 pounds). Vistra and EPA have developed a five-category sorting approach to classify removed modules by damage level and water or heat exposure:

- Type 1 (estimated ~35% of inventory): modules with no apparent functional damage but externally (and possibly internally) contaminated; removed and staged for cleaning, sorting and palletization. - Type 2 (estimated ~5%): modules in heat-affected zones or exposed to water; discharged with a load bank and shipped as damaged units. - Type 3 (estimated 5-10%): visibly or electrically damaged, severe water damage or corrosion; may be discharged by methods other than load-bank and potentially routed for grinding/crushing or special recycler processing. - Type 4 (estimated 5-10%): severely damaged modules or recognizable fragments; destruction or specialized disposal methods expected. - Type 5 (estimated ~50%): material consumed by fire or reduced to non-battery material; subject to hazardous/nonhazardous waste determination by sampling.

Disposal and recycler availability: Vistra and EPA identified at least one facility that EPA expects to approve for disposal: American Battery Technology Company in McCarran, Nevada. VISTA continues to search for additional recycling or disposal capacity; county staff cautioned that dedicated battery recycling facilities remain limited.

Staging and environmental controls: VISTA has prepared a staging pad (asphalt) outside the burned ash footprint but within the secured fence line to limit soil contact. VISTA and EPA conducted baseline soil sampling at the staging location to detect any change if contamination migrates from removal operations.

Community sampling and risk analysis: Monterey County Environmental Health reported on two phases of community sampling. Phase 1 (May 8 June 20) collected soils across Moss Landing and northern neighborhoods; preliminary labs from that round were expected in mid-July. Phase 2 will focus on marsh and slough sediment and surface water east of the facility; Vistra submitted a draft plan and county and state agencies commented in late June; Vistra's revised plan is due Aug. 11 with sampling expected in late August and results to follow. County staff stressed that community-sampling data will be quality-controlled and independently verified (DTSC confirmatory sampling and statistical comparison) before posting.

County toxicologists and consultants: County staff said an outside toxicologist concluded that a formal county human-health risk assessment cannot be quickly produced from raw lab reports; it requires cleaned, validated datasets and curated quality-control metadata (the county's public dashboard was designed for public communication, not as a QA-ready analytical dataset). Vistra's consultant (TerraPhase) was directed to prepare a preliminary environmental analysis that will include a human-health screening; state agencies (California Department of Public Health, Department of Toxic Substances Control, Office of Environmental Health Hazard Assessment) will peer review results before publication. County staff said the preliminary environmental analysis report is expected later in the year after sampling and confirmation analyses.

Oversight and public engagement: EPA will finalize a community relations plan and post a recovery web page with timelines and documents; county staff said EPA has assigned community-involvement coordinators and will run public engagement activities. Monterey County also has directed Vistra and EPA in a May 20 letter to remove the modules "safely and expeditiously," and both organizations replied. The board adopted a 60-day extension of the county's emergency proclamation related to the incident.

Why it matters: The Moss Landing fire released combustion products that are potentially hazardous to workers, residents and ecological resources. The planned ASAOC is intended to put legal responsibility on the site owner/operator to remove burned battery materials and to limit environmental and human-health risk during the removal.

What remains uncertain: Capacity for battery recycling remains limited nationally; the county and EPA said disposal or recycling methods will vary by module category and that some materials will require destructive disposal. Final human-health screening results will depend on additional sampling, confirmatory DTSC analyses and completion of TerraPhase's reports.