Devices powered by lithium-ion batteries have been overheating more frequently during airline flights, according to a report released by UL Standards on September 9. The study showed a 28% rise in overheating incidents between 2019 and 2023, though such occurrences remain uncommon.
The report, based on data from 35 passenger and cargo airlines, identified e-cigarettes as the most common device involved in overheating incidents, with 60% of these cases occurring near the seat of the passenger who brought the device onboard. UL Standards described these events as "thermal runaway," a condition where a battery overheats uncontrollably.
Recent incidents highlight the dangers of thermal runaway. In July, a smoking laptop in a passenger’s bag prompted the evacuation of a plane awaiting takeoff at San Francisco International Airport. Last year, a Dallas to Orlando flight made an emergency landing in Jacksonville, Florida, when a battery caught fire in an overhead bin.
The study revealed that over one-quarter of passengers admitted to placing e-cigarettes and portable chargers in checked luggage, despite federal regulations prohibiting such items. The TSA bans e-cigarettes and chargers with lithium-ion batteries in checked baggage, allowing them only in carry-on bags to prevent potential fires in the cargo hold.
Through mid-August 2023, the FAA recorded 37 incidents of thermal runaway on planes. In 2022, there were 77 incidents—a 71% increase compared to 2019.
Although the risk of battery fires in the air is relatively low, given that airlines operate about 180,000 U.S. flights weekly, the hazards of thermal runaway at cruising altitude are significant. "We also know that one of these thermal-runaway incidents at 40,000 feet does present unique risks," said David Wroth of UL Standards.
The most commonly reported overheating devices include phones, laptops, wireless headphones, and tablets, with 35% of incidents involving e-cigarettes and 16% involving power banks.
