Speaking to reporters Baroda town police commissioner Sudhirkumar Sinha said, “A big blast happened in the Koyali refinery which could be heard several miles away. The fire has been put out now and we are investigating the cause of the blast. It happened in the reactor of a portion of the main plant.

“Smoke was coming out from this plant around 3.30 a.m. and the district collector and fire brigade were informed. The fire was brought under control by fire fighters of Gujarat Refinery and other companies located in the area as it required special chemicals to put out and control it.

“It [is] not known whether there was anybody in the plant during the mishap. The casualties could have been higher, but only a handful of employees were in the premises as the plant had been shut down for maintenance,” he added.

In a statement IOC said, “The mishap took place in the fluid dyes catalytic cracking unit of the refinery, which was shut down since October 10 for regular maintenance and overhauling work.”

“The company rules out any possibility of sabotage and the plant is expected to be back on stream in next two days,” it added.

While the state-run firm did not elaborate further, reports in the media suggest the blast did not affect the production of LPG and motor spirit.