"Japan declared the Fukushima Daiichi crisis a Level 7 event on the international system for rating nuclear accidents Tuesday, putting it on par with the 1986 Chernobyl disaster in the former Soviet Union. The top-scale designation was based on the massive release of radioactivity since the accident began, particularly in its early days, and classifies Fukushima Daiichi a “major accident” requiring long-term countermeasures"