The feds are now looking into the replacement Galaxy Note 7 after one ignited on a plane

The federal agency overseeing the U.S. recall of Samsung’s Galaxy Note 7 says it is now investigating the replacement devices previously deemed safe, after one of the new models apparently overheated on board a Southwest Airlines flight Wednesday.

The U.S. Consumer Product Safety Commission said late Wednesday that it is investigating the incident, though it didn’t specifically say whether or not it recommends consumers continue to use the replacement models.

“CPSC is moving expeditiously to investigate this incident,” agency Chairman Elliot Kaye said in a statement. “Agency staff has already reached out to the FAA and Samsung to gather the facts about the incident. Agency staff will also reach out to the consumer who experienced a serious incident with his phone.”

Kaye added that those with recalled models should definitely power down their devices and “immediately take advantage of the remedies being offered by Samsung.”

And, while not commenting directly on the safety of replacement models, Kaye said: “Consumers should know that one of the remedies is a refund.”

Samsung said earlier Wednesday that it would work with Southwest and government officials.

“Until we are able to retrieve the device, we cannot confirm that this incident involves the new Note 7,” Samsung said. “Once we have examined the device we will have more information to share.”

The move comes as Samsung is working to replace the million or so Note 7 devices sold in the U.S. before sales were halted Sept. 2.

T-Mobile just resumed sales to new customers of the replacement Note 7s, while AT&T said it is only offering exchanges to existing customers at this point. Representatives for Verizon and Sprint did not immediately respond to requests for comment.

This article originally appeared on Recode.net.