Battery-powered devices are more likely to overheat on planes and trigger alarms

Lithium-ion battery-powered devices are more likely to overheat on flights, and passengers often put them in checked baggage, which then ends up in the hold, where any fires might not be detected as quickly.

The number of overheating incidents increased by 28% between 2019 and 2023, although such incidents are still relatively rare, according to a UL Standards & Engagement report released Monday.

According to the report, e-cigarettes overheat more often than any other device.

In 60% of cases, overheating — known as thermal runaway — occurred near the seat of the passenger who brought the device onto the plane.

In July, a smoking laptop in a passenger’s bag prompted the evacuation of a plane waiting to take off at San Francisco International Airport. Last year, a flight from Dallas to Orlando, Florida, made an emergency landing in Jacksonville, Florida, after a battery caught fire in the overhead bin.

More than a quarter of passengers surveyed said they put e-cigarettes and portable chargers in checked luggage. That’s against federal regulations.

The Transportation Security Administration prohibits e-cigarettes, chargers, and power banks with lithium-ion batteries from being carried in checked baggage, but allows them in carry-on baggage. The rule exists precisely because fires in the hold can be harder to detect and extinguish.

UL Standards & Engagement, part of the safety science company formerly known as Underwriters Laboratories, said it based its findings on data from 35 passenger and cargo airlines, including nine of the 10 leading U.S. passenger carriers.

The Federal Aviation Administration reports 37 incidents of thermal-induced aircraft escapes this year through Aug. 15. There were 77 such incidents reported last year, a 71% increase from 2019, according to the FAA.

Given that airlines operate about 180,000 U.S. flights per week, midair incidents are relatively rare, and lithium batteries can overheat anywhere.

“We also know that thermal runaway incidents at 40,000 feet pose unique risks,” said UL’s David Wroth.

This risk has been known for many years.

After cargo planes carrying lithium-ion batteries crashed in 2010 and 2011, the United Nations Aviation Authority considered restricting such shipments but rejected stricter standards. Opponents, including airlines, argued that the decision on whether to accept battery shipments should be left to carriers, and some no longer accept bulk shipments of batteries.

The most common lithium-ion-powered devices on planes are phones, laptops, wireless headphones, and tablets. About 35% of reported overheating cases involved e-cigarettes, and 16% involved power banks.