Lithium-ion battery fires aboard commercial aircraft have moved from a niche dangerous-goods concern to a broad operational exposure, according to a new analysis by WTW. Hull loss, passenger injury, diversion costs, airport emergency response, cargo claims, and business interruption all sit within the loss envelope of a single battery incident, the report said.
The chemistry of thermal runaway drives the exposure. When a lithium-ion cell enters thermal runaway, a self-sustaining internal reaction produces rapid heating, fire, toxic smoke, and repeated re-ignition. Standard aircraft fire extinguishers may knock down visible flames, but they cannot stop the underlying chemical reaction.
Crews must sustain cooling with large quantities of water or another non-alcoholic liquid to prevent the event from spreading to adjacent cells. That distinction between suppression and sustained cooling is now reflected in regulatory guidance. FAA Safety Alert for Operators SAFO 25002 directs operators to review procedures for overhead bins, where a developing incident may go undetected.
The FAA recorded 93 lithium battery incidents involving smoke, fire, or extreme heat on US aircraft in 2025, a 4.5% increase from the year before, according to data compiled from FAA records. Portable chargers accounted for 39% of all lithium battery incidents on aircraft reported since 2006. Vape pens were responsible for 21%, the FAA found.
A 2024 data review by UL Standards & Engagement drew on 37 airlines participating in its Thermal Runaway Incident Program and found thermal runaway incidents averaging two per week. Total aviation battery incidents rose 15% over the five years to 2024. Of incidents that occurred on the aircraft, 18% forced a diverted landing, return to gate, emergency evacuation, or unplanned deplaning, according to the review.
Real-world events have produced material losses. A January 2025 fire aboard an Air Busan aircraft at Busan, which WTW said interim investigators linked to a power bank insulation breakdown and short circuit, resulted in a total aircraft loss; all 176 occupants evacuated safely. In May 2026, an EasyJet flight from Egypt to the UK diverted to Rome after a passenger disclosed a power bank was charging in checked baggage in the hold.
On March 27, the International Civil Aviation Organization (ICAO) introduced global specifications limiting passengers to two power banks each and prohibiting in-flight recharging. The organization said the changes reflected "emerging expertise" around the risks posed by passengers' lithium-ion batteries, according to the WTW report. Airlines have added further restrictions on top: capacity limits, storage rules, and bans on use during specific flight phases.
The average US traveler brings four devices on a flight - smartphones, laptops, wireless headphones, and tablets - according to a 2024 ULSE survey of more than 12,000 adults. That volume, spread across hundreds of passengers per flight, makes the exposure systemic rather than isolated. Aviation has not yet reached a uniform passenger standard, with airline-specific policies varying well beyond the minimum regulatory requirements.
Cargo presents a separate and potentially more severe exposure, the WTW analysis notes. The US Pipeline and Hazardous Materials Safety Administration prohibits shipping lithium-ion cells and batteries as cargo on passenger aircraft. On cargo-only aircraft, standalone batteries must generally be charged to no more than 30%.
The 2010 crash of UPS Flight 6 in Dubai and the 2011 Asiana Airlines Flight 991 disaster both involved cargo fire scenarios that drew sustained scrutiny of battery fire loads and suppression limitations. The National Transportation Safety Board (NTSB) called for stronger detection and active suppression in 2012.
WTW notes the insured peril can originate from a consumer power bank, an incorrectly declared battery consignment, or a freight pallet of cells shipped within regulatory limits. The aviation insurance market enters this challenge under structural pressure: Gallagher Specialty's Plane Talking Q4 2025 found that attritional losses had eroded airline premium bases after several consecutive loss-making years, with underwriters seeking rate increases going into 2026.
For aviation insurers, battery incidents can no longer be treated as low-frequency edge cases. Managing the exposure requires demonstrable risk controls: crew training on two-step fire procedures, thermal containment equipment, passenger communications, and cargo screening protocols. The lithium-ion battery problem is not confined to aviation; the same suppression challenges are driving parallel losses in marine hull, a sign that the technology's reach as a systemic insurance risk extends well beyond any single line of business.
