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Japan raises severity of nuclear accident

This satellite photo taken Wednesday March 16, 2011 and provided by DigitalGlobe shows the damage after an earthquake and tsunami at the Fukushima Dai-ichi nuclear power plant complex. The satellite image confirms damage to the Units 1, 3, and 4 reactor buildings. Steam can be seen venting from the unit 2 reactor building, as well as from the Unit 3 reactor building. Additional damage can be seen to several other buildings approximately 350 meters north of the Unit 2 reactor building. Reactor units five and six are seen at lower right. (AP Photo/DigitalGlobe)

March 18, 2011 7:23:08 AM PDT
Japan's nuclear safety agency raised the severity rating of the country's nuclear crisis Friday from Level 4 to Level 5 on a seven-level international scale, putting it on par with the Three Mile Island accident in Pennsylvania in 1979. Ryohei Shiomi, a spokesman for the nuclear safety agency, said Friday that the agency raised the rating of the Fukushima Dai-ichi nuclear crisis on the International Nuclear Event Scale. The scale defines a Level 4 incident as having local consequences and a Level 5 incident as having wider consequences.

The hallmarks of a Level 5 emergency are severe damage to a reactor core, release of large quantities of radiation with a high probability of "significant" public exposure or several deaths from radiation.

A partial meltdown at Three Mile Island also was ranked a Level 5. The Chernobyl accident of 1986, which killed at least 31 people with radiation sickness, raised long-term cancer rates, and spewed radiation for hundreds of miles (kilometers), was ranked a Level 7.

France's Nuclear Safety Authority has been saying since Tuesday that the crisis in northeastern Japan should be ranked Level 6 on the scale.

- More coverage of the earthquake/tsunami

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