Citing safety concerns, Southwest Airlines will no longer allow passengers to charge devices with a power bank stowed inside a carry-on bag—going further than current FAA guidance.

These items can still be used during flights, but they need to be out of any baggage and remain in plain sight.

Portable chargers and power banks might be useful additions to your carry-on luggage, but they’re also a potential fire risk. Now Southwest Airlines is tightening rules around their use on board aircraft.