Chennai, Dec 27 : One worker was killed and another suffered severe injuries following an explosion at the Indian Oil Corporation's (IOCL) facility at Tondiarpet, in Chennai on Wednesday, sources confirmed. According to police, the incident took place when workers were welding a hole in an empty ethanol storage tank at the facility. A fire had broken out and was followed by an explosion killing one of the workers on the spot. Another worker who was seriously injured had been shifted to a hospital. The cause for the mishap is not known yet. The fire department and emergency services authorities explained that by the time they reached the spot, the fire was extinguished. Five fire tenders were rushed to the spot and an investigation is on. More details are yet to emerge regarding the incident and the IOCL is yet to make an official statement. /IANS