EXPLOSION AT NUCLEAR PLANT INTENSIFIES CRISIS IN JAPAN…. As if the devastation from the earthquake and tsunami weren’t serious enough, conditions grew even more serious today with an explosion at the Fukushima Daiichi nuclear plant.

An explosion at a nuclear power plant in northern Japan on Saturday blew the roof off one building, brought down walls and caused a radiation leak of unspecified proportions, Japanese officials said, after Friday’s huge earthquake caused critical failures in the plant’s cooling system.

Television images showed a huge cloud of white-gray smoke from the explosion. Soon afterward, government officials said an evacuation zone around the plant had been doubled, to 12 miles. The chief cabinet secretary, Yukio Edano, confirmed earlier news reports of an explosion at the Fukushima Daiichi nuclear plant, 15 miles north of Tokyo, saying: “We are looking into the cause and the situation and we’ll make that public when we have further information.” He was speaking amid fears that a disastrous meltdown could be imminent because of critical cooling failures at that plant and another nearby, Daini, after both were shut down.

Here’s video of the explosion, as aired by BBC:

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.