California is rapidly expanding the use of battery energy storage. These systems play an important role in storing electricity and helping support the state’s power grid, particularly as renewable energy becomes a larger part of the energy mix.
But recent incidents are also showing why energy storage is not simply an electrical issue. It is a workplace safety, fire prevention, environmental health, emergency response, and community safety issue.
A recent lithium-ion battery fire at the Metropolitan Water District’s Weymouth Water Treatment Plant in La Verne brought that point into focus. The fire began inside a battery energy storage system at the facility and resulted in evacuations in the surrounding area. Fire crews also had to monitor another battery storage unit that became overheated.
Metropolitan reported that its water supply and water quality were not affected by the incident and that water treatment operations continued. At the same time, local agencies remained involved in the response because of the potential hazards associated with damaged lithium-ion batteries.
Why battery fires are different
Lithium-ion battery fires can present challenges that are different from conventional fires.
One important concern is thermal runaway, a self-sustaining reaction in which excessive heat can cause a battery cell to fail and transfer heat to surrounding cells. In a large energy storage installation containing many batteries, that process can make an incident difficult to control.
Damaged batteries can also release hazardous gases when they burn. The U.S. Environmental Protection Agency notes that lithium-ion battery fires can produce hydrogen fluoride and other flammable or toxic gases.
That means emergency planning has to consider more than the fire itself. Responders may need to evaluate air quality, evacuation or shelter-in-place areas, access around the facility, battery temperatures, potential re-ignition, and appropriate protective equipment.
Energy storage is growing quickly
The need for this preparation is becoming increasingly important.
The California Energy Commission reported in August that the state had surpassed 21,000 megawatts of battery energy storage capacity. Battery systems are being used to store electricity generated during periods of abundant renewable energy and provide electricity when demand is higher.
With more facilities being installed, organizations need to think about safety throughout the entire life of an energy storage system — from design and installation to operation, maintenance, emergency response, and eventual decommissioning.
California’s Public Utilities Commission identifies safety planning, inspection, fire protection, standards, and first-responder outreach as important components of energy storage safety.
Safety doesn't stop when a fire is extinguished
One of the most important lessons from recent incidents is that emergency response may be only the beginning.
The cleanup at the Moss Landing battery facility illustrates this challenge. Following the major 2025 fire, EPA has been overseeing the removal, de-energizing, processing, and disposal of damaged batteries. The agency began the final phase of that work in September 2026.
Cleanup activities can involve damaged equipment, unstable batteries, contaminated materials, dust, fire debris, air monitoring, water management, and waste handling.
For facilities and contractors involved in these activities, environmental health and safety planning needs to continue well beyond the initial emergency.
What should facilities consider?
Organizations that operate or are considering battery energy storage systems should look beyond the equipment itself.
Emergency planning should address how first responders will access the site, how employees will be notified, what happens if a battery begins overheating, and how nearby communities could be affected.
Facilities should also understand their battery chemistry, fire protection systems, ventilation, monitoring technology, emergency shutdown procedures, inspection requirements, and plans for damaged or end-of-life batteries.
Communication matters, too. During an emergency, employees, responders, neighboring businesses, residents, and local agencies may all need timely and accurate information.
The California State Fire Marshal’s Battery Energy Storage Systems Workgroup is continuing to examine hazards, response practices, training, public education, and potential improvements to codes and standards. Its September 2026 meeting is scheduled for September 25.
Planning for safer energy storage
Battery storage can provide important benefits to California’s energy system, but its growth also requires careful attention to safety and environmental health.
Recent fires in La Verne and Moss Landing demonstrate why organizations should plan for the full range of potential hazards before an incident occurs. Good preparation means understanding the technology, identifying potential exposures, coordinating with emergency responders, maintaining appropriate monitoring and controls, and having a clear plan for both emergency response and cleanup.
As California continues to expand energy storage, safety needs to remain part of the conversation from the beginning — not after something goes wrong.
At Definitive Safety Group, we help organizations understand environmental health, workplace safety, emergency preparedness, and regulatory considerations so they can identify risks before they become larger problems.
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