Between 2021 and 2025, air cargo transport recorded 65 thermal runaway incidents linked to lithium-ion batteries, an overall increase of 40% and an average annual growth rate of 9%. This is according to the Thermal Runaway Incident Program (TRIP) report produced by UL Standards & Engagement, which highlights a structural vulnerability in the cargo sector: the number of shipments containing batteries is growing faster than the system’s ability to ensure their safety. The data should also be considered partial, as reporting is voluntary and often occurs under emergency conditions, suggesting the real number of incidents is higher.
The root of the problem is industrial before it is logistical. Global demand for low-cost electronic devices has driven a growing volume of non-compliant batteries onto the market, meaning products that have not been tested against international safety standards. According to the report, 60% of US adults are unaware that everyday devices are powered by lithium-ion batteries, and 50% say they are completely unaware of the risks associated with these components. This lack of awareness translates into practical errors during shipping, including inadequate packaging, missing or incorrect labelling, and failure to declare goods as hazardous materials. Those shipping a smartphone or a vacuum cleaner do not perceive them as risky cargo, yet they are.
The structure of the supply chain amplifies rather than contains the problem. Before being loaded onto an aircraft, a battery passes through manufacturers, wholesalers, freight forwarders, postal networks and third-party logistics operators. The system relies almost entirely on trust between actors, but the complexity of multimodal regulations, which vary across air, sea and land transport, creates significant opportunities for exploitation. E-commerce platforms and small operators, under pressure to cut costs, take advantage of regulatory grey areas, effectively creating a system that guarantees plausible deniability. When a fire breaks out, responsibility dissipates along the chain, leaving airlines to manage the emergency without the ability to hold any specific party accountable.
It is ultimately the air carriers that bear the burden of control. In the absence of stricter upstream regulatory oversight, the responsibility for identifying undeclared dangerous goods falls almost entirely on airlines, which lack the technical tools to inspect the contents of individual parcels. The result is a system in which risk is managed downstream, at the least suitable moment: on board the aircraft, when a fire can no longer be prevented, only contained.
The geography of risk is uneven. Analysing the 74% of incidents for which the airport of origin is known, the report finds that 42% of the shipments involved originated in Asia. A breakdown by departure airport shows Hong Kong as the origin in 27% of cases, followed by China (8%), South Korea, Malaysia and India (2% each). These figures must be read alongside the structure of global production: China accounts for around 85% of global battery cell manufacturing capacity, and the Asia-Pacific region represents 35.9% of the air cargo market. The concentration of incidents in this region reflects not only traffic volumes but also disparities in quality control and regulatory oversight between regions.
The risk does not concern dedicated cargo flights alone. In the United States, around 25% of air freight travels in the holds of passenger aircraft. Of the 65 incidents recorded in the period analysed, three occurred on this type of flight, with clear implications for onboard safety. Against this backdrop, the measures adopted by the industry remain largely reactive. The use of fire-resistant containers and thermal blankets addresses emergencies rather than providing a structural solution. The UL Standards & Engagement report identifies three priority directions for meaningful change.
The first concerns accountability. Regulatory gaps that allow responsibility to be shifted must be closed, requiring e-commerce platforms and manufacturers to ensure product compliance before goods enter the logistics chain. The second concerns training. Standardised, clear guidelines must be developed for small sellers, removing ambiguity over how to declare and package battery-powered devices correctly. The third, more structural, concerns the regulatory framework. Regulators and international bodies must impose uniform and binding rules so that compliance with safety standards becomes the economically rational choice for all actors in the supply chain, making it unprofitable, even before it is prohibited, to cut corners on controls in order to reduce costs.
P.R
