Four people died in a fire at a state-owned oil refinery in the southern Indian city of Vishakhapatnam and five workers were missing, dpa quoted police as saying Saturday. The fire broke out Friday at a refinery of Hindustan Petroleum Corp Ltd after an explosion at a distillery unit where expansion work was taking place, Vishakhapatnam Police Commissioner B Shivadhar Reddy said. The cause of the explosion was not yet clear but the fire was brought under control late Friday, Reddy said. More than 30 people were injured and some of them were in critical condition. Most of the victims were contract workers. Relatives of the missing workers staged a protest outside the refinery, the IANS news agency reported.