The firecrackers set off a fire on Saturday at the unauthorised warehouse at the Muno market in Su-ngai Kolok district in the southern province of Narathiwat bordering Malaysia, Narathiwat's Governor Sanan Phongaksorn said.
"There are 10 deaths plus the remains of two unidentified persons, which were sent for DNA checks," Sanan said.
He said 121 people were injured, two severely, while 111 had been discharged from hospital, he said. "But there should be no more deaths."
More than 200 houses surrounding the warehouse were damaged by the explosion, affecting 365 people. Some 19 people were still staying at a shelter as several families have moved to their relatives' houses, Sanan said.
Police were investigating the cause of the incident, he said, with initial reports suggesting a welding error at the warehouse.