Battery energy storage systems are being deployed closer to homes, businesses, and critical infrastructure than ever before. Urban substations, commercial districts, brownfield redevelopments, and mixed-use corridors are becoming viable storage sites.
Today’s regulatory framework largely assumes that thermal runaway can occur and defines success as preventing fire from spreading beyond the affected unit. In practice, this often means managing the incident by cooling surrounding systems and allowing the battery to burn out, or more simply, “let it burn.”
For remote locations, that approach may be manageable. For BESS near communities, it is becoming increasingly unacceptable as concerns grow about the health risks from toxic gases released during a lithium-ion battery fire.
Current Standard: Let It Burn
The foundation of modern battery fire evaluation is propagation testing.
UL 9540A focuses on thermal runaway fire propagation behavior and NFPA 855 integrates that evaluation into installation and spacing requirements. These standards have created consistency across jurisdictions and helped developers move projects through permitting.
However, the core logic remains centered on what happens after a cell enters thermal runaway. Systems are evaluated on how well they limit spread, contain fire within an enclosure, and support emergency response. Gas hazards are addressed but often treated as secondary concerns compared with flame propagation.
Emergency response plans reflect this logic:
- Isolate the affected unit
- Protect nearby equipment
- Allow the energy source to exhaust
- Monitor air conditions
In other words, contain it and manage it. For dense urban siting, that framework leaves a gap between regulatory compliance and public confidence.
(Image: Village of Warwick Mayor’s Office)
Containment Doesn’t Protect Communities
Containment prevents spread. It does not eliminate impact.
When a lithium-ion thermal event occurs, the hazard profile extends beyond visible flames. Toxic and flammable gases can be released. Carbon monoxide remains a primary exposure concern for responders and nearby residents, and hydrogen accumulation creates additional flammability and pressure risk.
Even if fire remains within a container, evacuation orders may still be issued. Roads can be closed. Schools and businesses may be affected. Air quality quickly becomes part of public conversation.
Smoke and residue create another layer of concern. After the Moss Landing fire, reports cited roughly 55,000 pounds of metal particulate contamination found in nearby soil samples, reinforcing why communities demand clear answers about environmental impact and cleanup.
Duration also matters. A battery incident can take hours to manage safely, and the site may remain restricted long after the flames are gone. In a city or town setting, that disruption affects daily life and makes communities far less willing to accept containment and burn-out as the safety plan.
Communities Are Pushing Back, Restricting Energy Storage Projects
The Sabin Center for Climate Change Law tracks opposition to renewable energy facilities nationwide. By mid-2025, the dataset identified at least 459 counties and municipalities across 44 states with severe local restrictions on renewable siting, up from 395 jurisdictions across 41 states the year before. The authors emphasize that the data is not exhaustive.
Not all of these cases involve batteries, but BESS projects are frequently part of local debates. Fire safety concerns are among the most common themes raised at public hearings.
Moss Landing amplified that concern and has become a reference point for community meetings across the country. Reporting described evacuation orders for 1,500 residents, large flames, dark smoke plumes, extended emergency response, and a significant capacity shutdown. EPA materials referenced large-scale fire conditions and the complexity of post-event assessment.
As restrictions increase, the development consequences become tangible. Moratoriums delay interconnection progress. Conditional use permits add engineering requirements late in the process. Some projects are redesigned while others are withdrawn.
What Current Standards Leave Unresolved
Updates to NFPA 855 and UL 9540A improved safety clarity and permitting consistency.
Large-scale fire testing under UL 9540A gives AHJs a documented framework for understanding system behavior under stress. NFPA 855 provides installation guidance that reflects those results.
However, these current standards primarily evaluate post-initiation performance. They assess how fire propagates, how it can be limited, and how responders can manage the event.
Communities want assurance that safety goes beyond burn-out planning and would benefit from a clearer prevention tier that aligns regulatory compliance with public expectations.
The good news is that prevention-first technologies already exist and are being deployed today.
Technologies That Close the Safety Gap
Alternative chemistries that avoid lithium-ion style fire behavior, such as aqueous flow and iron-air systems, are gaining attention but come with tradeoffs in footprint, performance, and economics.
Prevention-first lithium-ion system designs are emerging as practical ways to address the gaps that containment-focused standards leave behind.
Lithium-Ion Immersion Cooling
For projects that require lithium-ion performance, thermal management becomes central.
Immersion cooled systems completely submerge battery cells in a dielectric, non-toxic, high fire-point fluid. The fluid maintains uniform cell temperatures across the pack, reducing hotspot formation that contributes to degradation and thermal instability.
In addition to thermal management, immersion cooling also eliminates the chance of lithium-ion cells igniting and fires propagating. The liquid acts as a physical barrier that restricts oxygen access and heat escalation within the module. If a single cell fails and enters thermal runaway, the event remains isolated to that single cell.
For urban BESS, this prevention-first thermal control prevents a single cell failure from escalating into a multi-cell event that drives evacuation and community concern.
Hazardous Gas Neutralization
Lithium-ion cells can release hazardous gases including carbon monoxide, hydrogen, and hydrocarbons during abnormal thermal events.
A unique gas containment and neutralization system called HazGuard contains off-gases within the battery module and routes them through a physicochemical process that converts toxic compounds into inert outputs, similar to the catalytic converter in a vehicle.
By neutralizing flammable and toxic components, the system reduces exposure risk for responders and nearby residents.
When paired with anti-propagation technologies like immersion cooling, the gas neutralization system only needs to treat the gases from a single cell.
Eliminating toxic gas release is critical to protecting the environment, first responders, and surrounding communities.
What Communities and AHJs Should Require for Urban BESS
Urban BESS requires a consequence-based approach. The more people and infrastructure near a site, the higher the safety expectation should be. In many states and municipalities, that expectation already includes emergency response planning, environmental response protocols, and pre-operation inspections by fire authorities before a system is energized.
Communities and AHJs can align on additional safety standards that protect nearby residents by requiring prevention-first system performance, not just containment.
- Require systems that inherently prevent thermal runaway events from propagating. Thermal management architecture should reduce the probability of thermal runaway and stop propagation at the cell level.
- Require active neutralization of toxic battery gas emissions. Hazardous off-gases should be contained and converted into safe compounds, not simply detected and vented.
- Adopt a prevention-focused testing standard for propagation control. Testing should validate that a system prevents cell-to-cell propagation, not only how it behaves after propagation begins.
- End “let it burn” as a safety strategy. Urban BESS should not rely on burn-out as an acceptable safety outcome; fire prevention and gas control must replace containment-only outcomes.
These requirements would strengthen community confidence, reduce contested hearings, and increase the likelihood that projects reach commercial operation without prolonged delay.
Prioritize Prevention, Not Containment
The energy transition depends on battery storage. Communities also depend on safety and trust.
Burn-out containment manages the consequences of failure. Prevention reduces the probability and severity of failure. For BESS near communities, that distinction matters.
Burn-out cannot remain the baseline expectation for urban siting. Off-gas control must be elevated to a primary safety objective, and standards should evolve to recognize prevention-first architecture.
When systems are designed to prevent propagation and manage hazardous emissions, opposition decreases and permitting timelines stabilize. Safe BESS for communities is achievable, but it requires shifting from managing fire to preventing it.
To learn more about prevention-first battery architecture and what safe BESS for communities can look like in practice, explore EticaAG’s approach to community-ready energy storage.
