Thick black smoke billows above a plant of an agri-industrial firm in Barangay Hizon, Davao City when fire of still undetermined origin struck at around 5 p.m. on  Monday, 12 June 2012. An LPG tank of the plant exploded around 6:30 p.m. causing panic among residents nearby. This picture was taken at 6:03 p.m. Investigators are still determining the cause of the fire. MINDANEWS PHOTO