Nine people were killed Friday while over 100 others were injured after a devastating explosion at a firework warehouse rocked the Narathiwat province, Thailand, potentially due to welding during construction work in Sungai Kolok.

“A warehouse storing firecrackers in Sungai Kolok exploded this afternoon, the latest number is nine dead and 115 injured,” Narathiwat governor Sanan Pongaksorn.

“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,” he added.

Local television footage showed several stores, homes, and automobiles suffered extensive damage as a result of the blast’s force, while some were set ablaze and others’ roofs were peeled off.

Witnesses said that a massive cloud of smoke was seen rising into the air.

Up to 500 homes may have been damaged by the explosion in the border town near the Malaysian border, according to Thai PBS.

“I was playing with my phone inside the house then suddenly I heard a loud, thunderous noise and my whole house shook,” eyewitness Seksan Taesen, who lives 100 metres away from the warehouse.

“Then I saw my roof was wide open. I looked outside and I saw house collapsing and people lying on the ground everywhere. It was chaos.”

A video shot by Seksan showed a scene of turmoil at a local market, with dazed locals wandering around and emergency services rushing to help, the BBC reported.

Broken glass, roof tiles and other debris litter the ground.

Thailand has a poor safety record in the construction sector and deadly accidents are common.

In a similar incident last month, two people were killed when a road bridge under construction in Bangkok collapsed into traffic.