A pre-dawn fire that turned into an explosion in Tainan's Annan District has been traced to stored waste oil and scrap metal, and the fire department is now defending how crews handled it.

• The fire broke out overnight on Haidian Road and exploded while crews were on scene.
• What was reported as ordinary rubbish turned out to be waste oil drums, oil products, and scrap aluminum.
• Crews chose not to blast the fire directly with water because homes sat right next to it, focusing instead on stopping the flames from spreading.
• Heavy rain did not help — the pile kept burning inside and built up heat until the oil and resin-like material blew.
• Plans to smother the fire with earth or sandbags were still being arranged when the explosion happened.

Outlook: With the fire-scene forensics finished, attention now shifts to who stored the oil drums and scrap there and whether that storage was legal.