A fire broke out at a supermarket and spread to a nearby tea shop on Rajiv Gandhi Salai in Navalur on Sunday morning. The police said the fire that started in the supermarket spread to the tea shop and grew bigger after an LPG cylinder in the shop exploded, damaging the interior. However, as it was an holiday, the building was empty. Upon being alerted, firefighters from the Siruseri fire station reached the spot and put out the blaze. A preliminary investigation determined that an electrical short circuit caused the fire, a police official said.