It hasn’t been a great year for batteries.

Boosted Board CEO and founder Sanjay Dastoor just posted a notice asking owners of its newest electric longboard to stop riding them while the company investigates an issue with its batteries.

Specifically, they’re investigating two separate cases where the lithium battery cell on the second-gen board “vented” — in which a battery cell shows sign of smoke or unusually high heat. The battery enclosure is designed to contain any fires in the case of a cell failure — the company says this containment system “worked as designed” in both of the reported cases, and notes that there were no injuries in either case.

Users have been venting their frustration regarding the battery warning on reddit’s r/boostedboards, where user rickbross details his board filling his NYC apartment with smoke. The rider was not harmed.

While our review unit hasn’t shown any sign of troubles, I of course recommend that if you do have a Boosted Board 2 that you follow the manufacturer’s advice: power it off, don’t charge it, and keep it away from anything flammable until the company figures out what is happening.

Users who have pre-ordered the Boosted Board 2 have also been alerted that the shipments are halted until things get sorted.

TechCrunch has reached out to Boosted for comment. A spokesperson for Boosted declined to comment on the investigation, instead referring to the official statement mentioned earlier.