Authorities also said they have lost contact with 36 firefighters at the scene and 12 of them have been confirmed as among the dead. They were among more than 1,000 firefighters sent to fight the flames.
Around 520 people have been admitted to hospital, more than 60 seriously injured, the official Xinhua news agency said.
The first explosion, equivalent to three tonnes of TNT, happened at around 11.30pm local time, state broadcaster China Central Television (CCTV) reported.
The explosion, believed to have involved a shipment of explosives, sent huge fireballs into the air and triggered a blast wave that could be felt miles away, CCTV said.