Probe into gas blast at Achinsk refinery in the Krasnoyarsk region.
'The fate of three people is currently unknown'. Picture: Yulia Lebedeva, Channel 7 Krasnoyarsk
Seven other victims were hospitalised as a result of the tragedy which saw a fire sweep through the oil refinery.
'As a result of the fire five people were killed,' the Investigative Committee said in a statement. 'The fate of three people is currently unknown'.
The Siberian refinery is owned by state oil giant Rosneft.
The refinery processes 140,000 barrels a day and the blast was in a 'fractionation unit'.
While in another incident bystanders shoot a cell phone film of a man drowning, not thinking to call the emergency services.
Flight on Wednesday aborted two and a half minutes before blast-off as President Vladimir Putin watched at spaceport.