
The regulators said the rating was being raised from 5 to 7 - the highest level on an international scale overseen by the International Atomic Energy Agency. However, there was no sign of any significant change at the tsunami-stricken Fukushima Dai-ichi nuclear plant.
The new ranking signifies a "major accident" with "wider consequences" than the previous level, according to the Vienna-based IAEA.
"We have upgraded the severity level to 7 as the impact of radiation leaks has been widespread from the air, vegetables, tap water and the ocean," said Minoru Oogoda of Japan's Nuclear and Industrial Safety Agency.








