An underground oil tank exploded killing three people at an oil depot in the city of Petropavlovsk-Kamchatsky in Russia's Far East, the Emergencies Ministry reported.
"A 1,000 cu m empty tank exploded during welding work. The blast most likely occurred due to fuel vapors inside the tank," a ministry spokesman said, adding that three workers who carried out the work died, RIA Novosti reported.
"According to preliminary data, occupational safety violations were the reason for the accident," the spokesman said.