Samsung’s Galaxy Note 7 recall problems are far from over, as replacement units keep exploding. The first such incidents were reported in China a few weeks ago, just as the rest of the world was receiving safe Galaxy Note 7 handsets, the same type of devices that were commercialized in China. Then, earlier this week, a replacement Galaxy Note 7 blew up in an airplane just before takeoff. It’s not clear at this time what caused the explosion, but officials say that a second recall might be on the table.

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Samsung said in a statement that it couldn’t confirm what device exploded until it can investigate the matter. Meanwhile, the Federal Aviation Administration (FAA)and the Consumer Product Safety Commission (CPSC) are investigating the event, Bloomberg reports.

“If it’s the fixed phone and it started to smoke in his pocket, I’m going to guess there’ll be another recall,” former executive director of the consumer agency Pamela Gilbert told Bloomberg. “That just doesn’t sound right.”

“Certainly they could do another recall if it appears this is something beyond an aberration,” former acting chairwoman of the safety commission Nancy Nord said. “They need to determine if this was a remediated phone, and if so why did this happen?”

Meanwhile, the Louisville Metro Arson Squad is conducting tests on the burned Galaxy Note 7 to determine what kind of device it was. “Due to the damage to the phone itself, we have not been able to physically confirm that yet,” Captain Kevin Fletcher said. “We’re in the process of trying to attempt that.”

The captain also said there was “extensive heat damage” to the phone and the plane’s carpet. The phone remains in possession of the arson unit, which is looking to schedule lab tests.

The Bloomberg report also reveals one other interesting detail about the cause of original Galaxy Note 7 explosions that may have gone largely unnoticed. The original batteries that Samsung used for the phone were “slightly too large for the phone’s compartment.” The battery components were sometimes pinched, which could cause a short circuit, the safety commission said when announcing the recall on September 15th.