All evacuation orders, warnings and advisories were lifted Sept. 25, and Metropolitan confirmed Sept. 30 that all compromised battery cells had been removed from the plant.

Investigations and monitoring continue. The two unaffected battery systems remain out of service, isolated, reduced to a low energy level and monitored. Metropolitan has not provided an updated end date for all incident-related response activities.

Yes. Metropolitan confirmed Sept. 30 that all compromised battery cells had been removed from the Weymouth Water Treatment Plant.

In a subsequent email, a Metropolitan spokesperson said the removed cells were taken to a battery storage facility in Ohio. The agency has not provided the facility’s name or details about the cells’ eventual recycling or disposal.

The two unaffected systems remain out of service, isolated, reduced to a low energy level and monitored, according to Metropolitan.

They will remain offline while the agency investigates the fire and evaluates their future use.

That remains undecided. Metropolitan says it will determine future use after investigations are complete and related matters are resolved.

At the Sept. 29 special City Council meeting, Metropolitan Assistant General Manager John Bednarski said the agency would reconsider spacing between units if the systems are rebuilt, including whether greater separation could help prevent an incident in one unit from affecting another.

Metropolitan, its contractors and other appropriate parties are conducting investigations into the cause or origin of the fire, according to a Metropolitan spokesperson.

The cause has not been announced. The City’s incident webpage says the investigation is expected to take several months because it includes modeling and reconstruction of the incident.

City Manager Ken Domer declared a local emergency to support the City’s continued response to the incident. The City Council ratified the declaration during a special meeting on Sept. 29 at the La Verne Community Center.

Residents can monitor the City of La Verne website, and the La Verne fire and police departments’ social media accounts.

According to the City, particulate matter and heavy-metal results showed no meaningful difference from typical background conditions. Results described as “non-detect” mean substances were not detected above the equipment’s detection thresholds.

Those findings describe conditions at the monitoring locations and times. They do not establish whether contaminants entered an individual home or settled on soil or other surfaces.

Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said emergency air monitoring and an assessment of possible contamination at an individual property answer different questions. He had no sampling results from La Verne properties at the time of his interview.

Report bad smells, smoke, or dust to the South Coast Air Quality Management District's Online Complaint System or by calling 1-800-288-7664.

Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said odors during the fire or unusual deposits afterward can be reasons to consider a property assessment. However, appearance and smell alone cannot determine whether a property is contaminated or whether cleanup has been successful.

Metropolitan officials said the treatment plant continues operating and the community’s drinking water supply has not been affected.

Testing can help identify whether water used during fire suppression carried contaminants from the incident.

A Metropolitan spokesperson said runoff samples were collected by multiple entities, including the City of La Verne, Los Angeles County Public Works and Metropolitan. Testing and analysis are ongoing.

Runoff testing is separate from drinking-water testing. Metropolitan has said the plant continued operating and the community’s drinking water supply was not affected.

Results remain pending, according to Metropolitan’s latest response to La Verne Daily News.

Metropolitan says it will share its results when they are available and that the City has indicated it will do the same. The agency did not provide a new release date.

The extent of agency-led testing of soil, outdoor surfaces or conditions inside homes remains unconfirmed.

Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said ATEC was arranging private assessments for residents and had received inquiries involving soil, swimming pool water and interior surfaces. At the time of the interview, he had no sampling results from La Verne properties.

Private assessments are specific to the properties and materials examined. They do not establish conditions throughout the surrounding neighborhood.

Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said the decision depends on the circumstances of each property. Factors he considers include:

• Proximity to the fire.
• Whether the property was downwind during the incident.
• Whether smoke or odors entered the home.
• Whether unusual deposits appeared on windowsills, vehicles or other surfaces.

Those observations can help guide an assessment, but they do not establish contamination. Naffah did not identify a fixed distance within which every property should be tested.

For more information about ATEC Consulting's services, visit https://atechinc.net

Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said testing should be tailored to the composition of the batteries and other materials that burned, including wiring, casings and plastics.

Metropolitan has identified KORE Power as the battery manufacturer and the batteries are nickel-manganese-cobalt (NMC). That information, along with product records and details about surrounding materials, would help an environmental professional select appropriate tests.

A generic list of metals should not be treated as a confirmed list of substances released by this fire.

If an assessment identifies contamination requiring professional cleanup, Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said sampling shortly after the work is completed can help determine whether it was effective or whether additional cleanup is needed.

Naffah did not recommend routine repeated testing for every home. The need for further sampling depends on the initial findings, the cleanup performed and the potential for additional contamination.

Costs vary with the property, the professional hired, the materials sampled and the scope of testing.

For work he oversees, Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said assessments can cost roughly $2,000 to $5,000, while a comprehensive evaluation could cost $10,000 or more. Those figures are examples from his experience, not standard prices for every company or property.

Metropolitan accepts claims for fire-related expenses and losses, but submitting a claim does not guarantee reimbursement. Residents with questions about potential coverage can email Metropolitan at rmanagement@mwdh2o.com or call (213) 217-7715.

Not necessarily. Patrick Naffah, director of environmental health and safety at ATEC Consulting and a certified industrial hygienist and certified safety professional, said his firm generally provides its report to the homeowner or other client who commissioned the assessment. Those reports are not automatically published or submitted to local agencies.

A homeowner may choose to share a report, but its findings apply to the locations and materials sampled.

Yes. All evacuation orders, warnings and advisories related to the battery fire were lifted at 6 a.m. Sept. 25. Businesses in the former evacuation area were also allowed to reopen.

The lifting of an evacuation order addresses the immediate conditions that prompted residents to leave. It does not establish whether fire-related residue is present at an individual property.

Residents concerned about possible smoke or residue inside their homes can consider a property-specific assessment.

Fire personnel and lithium-ion battery experts worked overnight to remove battery modules from the affected enclosure. The City said that work eliminated the potential hazard to the surrounding community, allowing all evacuation orders, warnings and advisories to be lifted at 6 a.m. Friday, Sept. 25.

No part of La Verne is currently under an evacuation order, warning or advisory related to the battery fire. All evacuation notices were lifted at 6 a.m. Friday, Sept. 25.

Fire officials used major streets to create boundaries that residents could easily understand and recognize. The mandatory evacuation area was designed to include the entire 186-unit La Verne Mobile Country Club, as well as nearby residential streets east of the Weymouth plant.

La Verne Fire Battalion Chief Mark Savage said the boundaries are not based on a fixed mathematical distance from the battery systems. They are driven by the incident, including the locations of nearby residents, conditions at the plant, and the potential direction of smoke if another fire occurs.

Officials reduced the original evacuation area as conditions changed. During the incident, residents were advised to check Genasys Protect for their address rather than relying solely on their distance from the plant.

Emergency boundaries must follow identifiable streets and other landmarks so residents and responders can clearly understand them. That means homes close to one another may receive different instructions. Officials said they drew the boundary to remove those considered most at risk, and it may change if conditions warrant.

Residents outside the mandatory zone were advised to monitor Genasys Protect because some were within an evacuation-warning area. All evacuation orders, warnings and advisories were lifted Friday morning.

Residents in the red evacuation-order zone are required to leave because fire officials believe they need to be removed from potential danger. People in a yellow evacuation-warning area are not required to leave, but they may if they believe it is safest for them. Officials said they would support residents who voluntarily leave a warning area.

No evacuation orders or warnings related to this incident remain in effect.

Law enforcement officers conducted door-to-door outreach at approximately 504 homes during the evacuation. All evacuation orders, warnings and advisories were lifted Sept. 25.

Hillcrest returned to normal operations after air monitoring detected no contaminants associated with the fire. All evacuation warnings and advisories related to the incident were lifted Sept. 25.

Grace Miller Elementary was closed as a precaution because of its proximity to the evacuation area and the difficulty of quickly evacuating hundreds of students if conditions suddenly worsened. Officials were concerned that the batteries could flare up or that changing winds could carry smoke toward the campus while students were at school or traveling there.

Other Bonita Unified schools remained open.

Families should follow Bonita Unified School District’s ParentSquare messages for information about when the campus will reopen.

Bright Beginnings Preschool opened with their normal hours on Monday, Sept. 28.

Damien High School and Calvary Baptist Schools remained open during the incident.

Students who live in zones that were identified as mandatory evacuation and warning evacuation zones and did not attend school because of the incident will receive excused absences, according to Bonita Unified School District.

Excused absences are recorded on a student’s attendance record, but students do not face the consequences associated with truancy.

The District said it does not receive state Average Daily Attendance funding when a student is absent, even when the absence is excused. However, because Grace Miller Elementary School was required to close, the District said it will apply to recover attendance funding for that campus. The Los Angeles County Office of Education will help the District submit documentation to the state explaining the closure.

The incident occurred at the F.E. Weymouth Water Treatment Plant near Wheeler and Moreno avenues in La Verne.

KORE Power manufactured the battery energy storage systems, according to a Metropolitan spokesperson.

ELM Microgrid supplied and installed the systems under a subcontract with the project’s prime contractor, Siemens Industry Inc.

Metropolitan has identified KORE Power as the battery manufacturer and the batteries are nickel-manganese-cobalt (NMC).

Metropolitan installed approximately 2 megawatts of solar panels at the plant about 15 years ago to reduce its electricity use. The battery systems were added to store solar-generated electricity and allow parts of the plant to reduce their reliance on the electrical grid during peak hours, generally from 4 to 9 p.m.

Metropolitan described the batteries as a “peak-shaving” system intended to reduce demand on Southern California Edison’s grid.

Metropolitan’s La Verne complex has four separate 250-kilowatt lithium-ion battery systems with a combined rated power of 1 megawatt. The two systems on the north side were affected by the incident and rendered inoperable. The two systems on the south side were unaffected and were taken offline and de-energized Sept. 25.

The system was commissioned in mid-2026 and remains under warranty. Metropolitan has not provided its energy-storage capacity in megawatt-hours or identified the specific lithium-ion chemistry.

Metropolitan officials said the agency’s construction management team inspected the installation during construction and tested the units before accepting them from the contractor in June 2026.

The project did not undergo City planning approval. City officials say Metropolitan, as a separate governmental district, is exempt from the City’s planning procedures.

The complete approval process and the project’s specific environmental-review determination have not been provided to La Verne Daily News.

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City officials say the installation did not undergo the City’s planning approval process because Metropolitan is exempt from those procedures.

That explanation addresses City planning oversight. La Verne Daily News has not received a complete accounting of other permits or approvals associated with the installation.

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Yes. Fire Chief Brandon Coatney said Metropolitan voluntarily provided a site plan in 2022 showing where the equipment would be located.

Coatney said the plan met applicable property-line distance requirements at the time. The fire department recommended installing a nearby fire hydrant, and Metropolitan followed that recommendation.

That site-plan review was separate from the City’s planning approval process.

Yes, according to Metropolitan. A spokesperson said a Failure Modes and Effects Analysis, or FMEA, was conducted for the project. The agency described it as a form of hazard mitigation analysis authorized by the California Fire Code.

Metropolitan has not provided the report, its findings or details identifying who reviewed and approved it.

Yes, according to a Metropolitan spokesperson. The agency said a large-scale fire test was conducted and its results informed battery spacing and project design.

Metropolitan has not provided the test report or details explaining the test conditions and how its findings were applied to this installation.

At the Sept. 29 City Council meeting, Metropolitan said it would reconsider spacing if the systems are rebuilt.

BESS stands for Battery Energy Storage Systems. BESS use rechargeable batteries to store electricity for later use, according to the U.S. Department of Energy.

Officials said individual battery cells may experience small explosions during thermal runaway. However, they said those events are not expected to pose an explosion risk to the surrounding community.

Yes. A Metropolitan spokesperson said the systems have fire-detection and fire-suppression equipment. An investigation will determine whether those systems operated effectively and what caused the incident.

Metropolitan said it and its emergency-response partners had plans in place before the fire. The agency said it regularly communicates with the La Verne Fire Department and provides the department with background information about the facility.

Metropolitan also said it conducts emergency-preparedness exercises and activities with first responders. The most recent took place in June 2026. The agency did not provide additional details about whether that exercise specifically involved the battery systems.

The cause remains under investigation.

Metropolitan says it, its contractors and other appropriate parties are investigating the cause or origin of the fire. No findings establishing the cause have been announced.

Metropolitan has not confirmed whether it will release the complete investigation reports or when findings will be available.

Its commitment to share runoff-water testing results is separate from the question of whether the fire investigation reports will be made public.

One Metropolitan employee was injured after tripping and falling while leaving the area on Tuesday, Sept. 22. The employee was taken to a hospital in good condition. No firefighters were injured.

Residents and businesses affected by the fire at the F.E. Weymouth Water Treatment Plant may submit claims to the Metropolitan Water District of Southern California, according to the City of La Verne’s website.

Claimants should complete Metropolitan’s claim form and follow the submission instructions included with it. Questions may be directed to rmanagement@mwdh2o.com or (213) 217-7715.

Tri-City Mental Health offers free emotional support, crisis care and resource referrals for affected residents and families. Learn more free local emotional support, crisis care and resource referrals available to our community.

Report bad smells, smoke, or dust to the South Coast Air Quality Management District's Online Complaint System or by calling 1-800-288-7664.

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