A new report is casting fresh light on one of the most persistent risks in air cargo: the growing number of lithium-ion battery incidents linked to global shipment flows.
Research from UL Standards & Engagement (ULSE) shows that the air cargo sector recorded a 40% rise in thermal runaway incidents between 2021 and 2025. Reported cases climbed from 10 in 2021 to 14 in 2025, after reaching 13 incidents in 2022, 13 in 2023, and 15 in 2024.
ULSE described the trend as alarming and said it reflects the expanding global appetite for low-cost, battery-powered consumer products—particularly through e-commerce channels.
Bob McClelland, transportation safety lead at UL Standards & Engagement, said the increase is not random. In his view, it reflects identifiable structural weaknesses in battery quality, shipper awareness, regulatory oversight, and supply chain accountability.
The report says two of the most important drivers of risk are product quality and shipper behavior. Smaller or occasional shippers often lack hazardous materials expertise and rely heavily on carriers to catch documentation or packaging errors, pushing responsibility further down the chain.
At the same time, oversight remains inconsistent. ULSE said limited enforcement in some parts of the world leaves cargo airlines managing risks they did not create and often cannot fully see.
Geography also appears to matter. The report found that, where origin and destination airport information was available, shipments originating in Asia accounted for 42% of incidents. That included Hong Kong at 27%, China at 8%, and South Korea, Malaysia and India at 2% each.
ULSE cautioned that this pattern must be read in context: Asia also handles a very large share of global battery shipments, so higher incident counts partly reflect higher volumes. Even so, the report suggests that regional differences in manufacturing standards, compliance practices and enforcement rigor may amplify the underlying risk.
A battery’s country of origin, ULSE said, can therefore serve as one indicator of heightened exposure.
Another challenge is accountability. Battery shipments often pass through multiple parties—manufacturers, sellers, shippers, forwarders and carriers—with each relying on the previous actor to comply with the rules. According to ULSE, that fragmentation diffuses responsibility and makes it difficult to identify root causes or implement durable corrective action after incidents occur.
To improve cargo safety, the report outlines three main priorities: establishing clear and enforceable responsibility across the supply chain, strengthening education and global coordination to reduce ambiguity, and treating safety and cost as aligned priorities rather than competing objectives.
As Emily Brimsek, senior manager of qualitative insights, put it, one conclusion emerged consistently across interviews and focus groups: reducing battery fire risk must be understood as a shared responsibility—and one that depends on deliberate action, not luck.
