The Japanese nuclear agency has “provisionally” raised the threat level from a stricken power plant from 5 to 7, the most severe category.

The 1986 Chernobyl accident in the former Soviet Union also rated a 7 on the International Nuclear Events Scale, which equates to a “major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures.”

A Japanese official says the release of radiation at the Fukushima Daiichi plant is about 10% of what was emitted at Chernobyl.

– CNN