At least three people were killed Tuesday in two separate boiler station explosions in Russia, the Interfax news agency reported. A female heater operator, who forgot opening a shutter baffle, was seriously burned by overheated steam and died in hospital hours after the heater blew up in the village of Chelbasskaya in the southern Krasnodar region. Another explosion occurred in the town of Nalchik in North Caucasus, killing at least two people, a spokesman for the regional emergency ministry said. Rescuers kept searching on the blast scene as there might be other people buried under the rubble, he added.