Five workers were killed in a powerful explosion inside a factory in Chhattisgarh’s Abhanpur, about 35 km east of state capital Raipur, at around 2am on Friday, police said. The incident took place at Navbharat Fuse Company Ltd, a manufacturer of explosives, detonators and electrical fuse, while the workers were sleeping inside the factory. “The blast was so powerful that it blew off the concrete building of 1,600 square feet and killed all five workers inside. The exact cause of the explosion is not known. The factory supervisor who was away from the premises informed the police,” Raipur superintendent of police OP Pal told Hindustan Times. All those killed were local residents. “Investigation is on,” said Pal. The area has been cordoned-off by the police.