On the Move: Hazards + Safety Lessons From Battery Energy Storage System Transport Incidents

Understanding the Unique Hazards of BESS in Transit

Transporting Lithium-ion Battery Energy Storage Systems (BESS) containers presents a different risk profile than that of fixed, stationary installations. Mechanical stress, vibration, improper securing, road collisions, temperature extremes and inadequate ventilation in enclosed trailers can all contribute to thermal runaway or other failure modes. Unlike in a stationary setting, BESS in transit often lack active monitoring or integrated annunciation features such as detection, alarms or remote monitoring that can alert operators or responders to early fault conditions. As a result, BESS safety during transport relies heavily on packaging integrity, containment design and passive controls.

In July 2024, a semi-truck carrying a large container with lithium-ion BESS overturned on I-15 near Baker, California, resulting in a fire that shut down the highway for more than a day. According to the California Department of Transportation (Caltrans), the remote desert location, high ambient temperatures, difficulties in moving the heavy container and the risk of rapid fire spread and toxic gases associated with the incident added complexity to the response and prolonged the incident. [Northbound I-15 Closure Near Baker Due to Lithium Battery Fire. California Department of Transportation News Release No. 2024-027, July 28, 2024. https://dot.ca.gov/news-releases/news-release-2024-027 ]

In September 2024, a truck carrying a containerized BESS overturned near the Port of Los Angeles in San Pedro, California, igniting a prolonged fire and experiencing a deflagration, forcing a closure of the Vincent Thomas Bridge for more than 24 hours. According to the Los Angeles Fire Department, an explosion occurred inside the trailer after the rollover, blowing out one side of the container and igniting the cargo. Firefighters allowed the batteries to burn under controlled conditions to prevent contaminated runoff and later relocated the trailer to a vacant rail yard for continued monitoring until the fire burned out. No injuries were reported. [Lithium-Ion Batteries Burn for Days After San Pedro Big Rig Crash.” Los Angeles Fire Department News Release, September 27, 2024. https://lafd.org/news/lithiumion-batteries-burn-days-after-san-pedro-big-rig-crash ]

Both events demonstrated how transport-related damage can initiate thermal runaway and how challenging it is to control large battery fires once they begin. They underscore the need for transport-specific safety practices that keep pace with the progress already made in stationary BESS standards.

Regulatory Gaps and Oversight Challenges

Most U.S. transportation safety regulations for lithium-ion batteries fall under the Department of Transportation (DOT) and United Nations (UN) 38.3 testing requirements. However, these rules primarily address the transport safety of smaller battery cells, modules and packs, not full racks, units or containerized systems. BESS containers moved between manufacturing facilities, testing labs, staging warehouses, ports or project sites often fall into a grey zone: too large to qualify as standard cargo, yet not subject to specialized fire protection or monitoring measures.

There is currently no unified requirement in standards like NFPA 855, UL 9540 or CSA/ANSI C800 that provides guidance on safety principles specific to BESS in transport. This gap creates a fragmented regulatory landscape where transportation of BESS can slip through oversight cracks.

Key Lessons from the Incidents

1. Transport introduces unique failure triggers. Both incidents were caused by mechanical damage from rollover crashes rather than internal battery faults. Impact, vibration and deformation during transport can compromise modules or wiring, leading to short circuits and thermal runaway. Even when systems are shipped at low state of charge (SOC), physical damage can quickly escalate into a full battery fire.
2. Monitoring and detection are absent during transit. Neither container included active smoke, fire or gas detection systems, nor any annunciation to alert operators or responders. Without these early warning features, first responders became aware of the fire only after visible flames and explosions occurred, losing valuable time for safe response.
3. Response training and coordination remain limited. First responders approached both incidents as typical vehicle or trailer fires before realizing they involved lithium-ion energy storage. Current training focuses on electric vehicle or stationary BESS events, not large containerized systems in motion. Transport-specific guidance and communication with local authorities are needed to improve response readiness.
4. Packaging and enclosure design influence fire behavior. The absence of dedicated venting, internal barriers and fire-resistant separation contributed to gas accumulation and prolonged burning. In San Pedro, the confined container environment allowed gases to build up before the deflagration. On I-15, poor containment and limited spacing within the trailer worsened the fire spread and duration.

BESS Safety During Transit

A proactive BESS transport safety strategy should include:

• UN-certified packaging and containers designed to withstand drop, crush and fire exposure, with physical separation between battery units to limit propagation.
• Clear hazard labeling and signage on all container sides, including emergency contact and response information, to help responders quickly identify lithium-ion BESS cargo.
• Controlled SOC, typically limited to 30% or lower, to reduce available energy and slow thermal runaway progression.
• Ventilated trailers or containers equipped with real-time monitoring and detection to prevent gas buildup and provide early warning.
• Thermal insulation and fire-resistant linings to contain heat release and delay exposure of adjacent battery units.
• Pre-transport checks to identify any signs of damaged batteries, loose wiring or residual charge and to verify secure mounting of enclosures.
• Training for drivers and carriers focused on battery-specific hazards, warning signs of failure and safe isolation techniques in case of smoke or gas detection.
• Advanced coordination with local fire departments and emergency services along major shipping routes for awareness and response planning.

Improving BESS transport safety will also require collaboration across the industry. Authorities, DOT regulators, BESS manufacturers and logistics providers are encouraged to work together to develop clear transport-specific guidelines for BESS. As batteries scale, their risk travels with them. Establishing consistent design, monitoring and response expectations for BESS in transit is the next step toward ensuring that safety principles apply across the entire battery lifecycle, from factory to field.

What This Means for BESS Projects

As BESS installations grow in both size and number, so will the logistical operations behind them. BESS containers are often shipped across multiple states, often by third-party carriers who may be unfamiliar with the hazards associated with them.

If you’re involved in the design, commissioning or operation of BESS, consider transport risks early in your planning:

• Ask manufacturers how their systems are packaged, labeled and handled during transit
• Incorporate transportation safety considerations into your hazard mitigation and risk management planning
• Evaluate whether emergency response partners along key routes are equipped to handle BESS-related incidents

Safe energy storage requires safe logistics. BESS safety doesn’t start when the system is energized; it starts when the system hits the road. Incorporating transport safety into early project planning helps avoid delays, supports compliance and strengthens overall system resilience. 

Want to talk about how your BESS transport safety could affect your fire safety planning or permitting needs? Our team is here to help.