A passenger on a February 19th flight from Beijing, China to Melbourne, Australia was burned when her headphones caught fire. The incident was detailed in a report released today by the Australian government’s Transport Safety Bureau, which stated that the headphones’ batteries were the likely the cause of the fire. The passenger’s name, the name of the airline, and the brand of the headphones were not released.

The ATSB says that “a loud explosion” was heard about two hours into the flight. The injured passenger had been sleeping when the headphones exploded. “As I went to turn around I felt burning on my face,” she told the ATSB.

The ATSB didn’t name the headphone brand

The passenger says she pulled the headphones down around her neck and then threw them on the floor when she realized they were still on fire. The headphones were sparking when flight attendants doused them with a bucket of water. The batteries were seen melted to the floor once the smoke cleared.

Lithium-ion batteries, which are common in these types of electronics, are susceptible to what’s known as “thermal runaway.” Basically any increase in heat, whether it’s from a fault in the batteries or an outside source, can cause the electrolytes to react with the battery’s other chemicals. This creates a gas, which in turn increases the heat more, and so the problem escalates — sometimes explosively.

It’s unclear if this is exactly what happened on the flight in question, but considering thermal runaway was behind the problems with the Samsung Galaxy Note 7 and exploding hoverboards, it’s a likely culprit.