Four people have been injured in a fire following an explosion at a chemical factory in Boksburg, east of Johannesburg.

Johannesburg Emergency Services say 25 firefighters have been dispatched to the factory to contain the fire. Parts of the factory are reported to have been completely destroyed.

Johannesburg Emergency Services spokesperson William Ntladi says all the injured have been taken to hospital and one is in a serious condition.

It’s not clear how many people were on the premises of the factory at the time of the explosion.