The explosion took place at around 03:00 p.m. local time (08:00 GMT) in the Thai town of Su-ngai Kolok, bordering Malaysia, at a warehouse of the fireworks factory where construction work was underway at the time, the Thairath daily newspaper reported.
The preliminary police data suggest that the explosion was caused by a spark that flew into a box of fireworks during the welding of metal structures, the newspaper reported. The fire caused by the blast was extinguished by 04:30 p.m. local time, the report said.
“A warehouse storing firecrackers in Sungai Kolok exploded this afternoon, the latest number is nine dead and 115 injured,” Narathiwat Governor Sanan Pongaksorn told the AFP news agency.
“The fire is now under control. Preliminary investigation suggests the cause is a technical error during the steel welding process, as the building is under construction.”
The police and the provincial administration launched an investigation into the incident, the Thairath daily newspaper added.