Two members of Japan’s Diet call for the Fukushima Daiichi nuclear power station to be nationalized. Writing in a Comment article in this week’s Nature, two Members of the House of Representatives, Tomoyuki Taira and former prime minister Yukio Hatoyama, argue that public ownership is essential to bring into the open basic evidence about events that rocked the plant during and after the March 2011 earthquake and tsunami.

As part of an independent committee that is investigating the accident, the politicians describe how various nuclear-industry bodies have been slow or obstructive in providing evidence to help ascertain what has taken place. For example, key passages in a manual from Tokyo Electric Power Company were blacked out in an initial submission to their team, and only reinstated months later.

Major questions remain unresolved, such as whether the nuclear cores are still active, what caused the explosions in the days following the earthquake and to what degree molten fuel has eaten through the reactor bases. The power station must be brought into government hands, they say, so that independent scientists can assess the situation and help to develop adequate long-term responses.