Beds are burning: mattresses aflame as fire rips through Adelaide factory

Residents have been warned to stay indoors as a burning mattress factory in Adelaide pours thick smoke into the sky.

Fire crews responded to the emergency at 5.30am, with up to 60 on the scene.

The fire has been contained and no neighbouring properties are at risk, but there is still a serious smoke hazard in the suburb of Hackham.

No injuries have been reported.

The cause of the fire is not yet known.