The alert is Tokyo 's gravest warning since meltdowns at the nuclear plant in 2011 . The Japanese regulator made the decision after consulting with the The Nuclear Regulation Authority . A storage tank at the plant leaked About 400 tons of toxic water . A government minister 2011 criticized the plant operator 's handling of leaks .
The alert is Japan 's gravest warning since meltdowns at the nuclear plant in 2011 . The Japanese regulator made the decision after consulting with the IAEA . A storage tank at the plant leaked hundreds of tons of toxic water . A government minister this week criticized the plant operator 's handling of leaks .