The blast caused disruption to the Severnaya Thermal Power Plant, which heats hundreds of thousands of homes at a time when temperatures are around minus 5C.
The plant provides electrical and thermal energy to factories, residential areas and public buildings in the northern part of the Vyborgsky and Kalininsky districts of St. Petersburg, as well as the settlements of Novoe Devyatkino and Murino, and the Vsevolozhsky district of the Leningrad region.
In total more than 800,000 people receive heat from the Severnaya plant.