The Japanese government's nuclear safety agency has decided to raise the crisis level of the Fukushima Daiichi power plant accident from 5 to 7, the worst on the international scale.
The Nuclear and Industrial Safety Agency made the decision on Monday. It says the damaged facilities have been releasing a massive amount of radioactive substances, which are posing a threat to human health and the environment over a wide area.
The agency used the International Nuclear and Radiological Event Scale, or INES, to gauge the level. The scale was designed by an international group of experts to indicate the significance of nuclear events with ratings of 0 to 7.
On March 18th, one week after the massive quake, the agency declared the Fukushima trouble a level 5 incident, the same as the accident at Three Mile Island in the United States in 1979.
Level 7 has formerly only been applied to the Chernobyl accident in the former Soviet Union in 1986 when hundreds of thousands of terabecquerels of radioactive iodine-131 were released into the air. One terabecquerel is one trillion becquerels.
I have colleagues in Osaka. The distance from Osaka to Fukushima as the crow flies is 332.18 miles. That's a little less than the distance from my house to Richmond, Virginia.