Gov Huseyin Avni Mutlu ruled out any terrorist attack and said the blast was caused by a gas leak or a gas canister.
The explosion in a packaging workshop on the ground floor of the building caused a fire which was quickly extinguished, the private Dogan news agency reported.
Mutlu's office said eight people were injured in the blast; one person was in serious condition. A fire-fighter was treated for smoke inhalation, it said.
Hurriyet newspaper and other reports said the injured included a pregnant woman who jumped from a balcony on the second floor of the building. Hurriyet said some cars were overturned by the force of the blast.