Large areas surrounding Japan's Fukushima Daiichi nuclear plant may be declared uninhabitable following an announcement by the Ministry of Science and Education that radioactive contamination far exceeded safe levels. The affected communities are located within 12 miles of the plant, which Prime Minister Naoto Kan plans to visit as early as Saturday to break the news to the residents firsthand. The announcement is the first formal recognition that the March accident could cause up to a decade-long depopulation for the surrounding towns and villages. The government is also planning ways to compensate the displaced residents. A survey in Okuma, one of the most contaminated towns, showed that a yearlong resident would be exposed to 508.1 millisieverts of radiation—far above the 20 millesieverts per year considered safe.