Prosecutors on Monday decided not to indict former Prime Minister Naoto Kan or any officials from Tokyo Electric Power Co. over the nuclear disaster at the Fukushima No. 1 plant because of the lack of criminal responsibility.

“It was difficult to foresee the scale of the earthquake and tsunami,” the Tokyo District Public Prosecutor’s Office said of the government’s response to the natural disasters in Tohoku that triggered the man-made meltdowns in Fukushima Prefecture in March 2011.

About 14,700 people from groups across Japan, but mainly in Fukushima Prefecture, filed complaints against Kan and 41 other individuals for alleged professional negligence resulting in death and injury in connection with the nuclear disaster, which was triggered when the poorly protected power station lost all power after being hit by the quake and subsequent tsunami.

Kan, who was prime minister from June 2010 to September 2011, called the prosecutors’ decision “a natural outcome.”

But residents dissatisfied with the ruling will request that an 11-member independent inquest panel review the case. The groups said they are now planning to take their case to the Committee for the Inquest of Prosecution in Tokyo, where the investigation was handled.

In addition to Kan, the accused included Tsunehisa Katsumata and Masataka Shimizu, who were chairman and president of Tepco at the time, and Haruki Madarame, then chairman of the now-defunct Nuclear Safety Commission.

The focus was on whether prosecutors could find enough evidence to prove that the government and Tepco failed to take sufficient measures at the 40-year-old power plant after being notified of the risk of earthquakes and tsunami.

The government and Tepco were also accused of delaying the evacuation of residents around the plant, causing many to be exposed to radiation and leading to the deaths of many bedridden hospital patients.

Asked about the prosecutors’ decision, Chief Cabinet Secretary Yoshihide Suga said at a news conference that he would not comment on the conclusions of investigations conducted in individual cases.