One firefighter was killed, five others were injured and two missing in a fire at an oil tank in west Siberia overnight, Russian media reported on Sunday. The No. 7 oil tank in the Khanty-Mansi autonomous area exploded and triggered a blaze, the Ural regional center of Russia's Emergency Situations Ministry said. 'The explosion destroyed tank No. 7 ... then spread to tanks 5 and 8,' the Itar- Tass news agency reported citing a source from the regional center. An area of more than 2,000 square meters at the station is currently ablaze. The capacity of the oil tank is 20,000 cubic meters each. One firefighter died when trying to extinguish the fired. Two more firefighters were still missing. Preliminary investigation indicated that the No. 7 oil tank was struck by a bolt of lightning. 