The Tokyo District Court ruled that it was not realistic for the former executives to have predicted all possible tsunami scenarios and thereby prevent the triple core meltdown, which forced hundreds of thousands of residents to evacuate and contaminated wide areas of the prefecture.

In concluding the two-year trial, presiding Judge Kenichi Nagabuchi ruled that the trio could not have foreseen the 9.0 magnitude earthquake, which caused massive tsunami and knocked out critical cooling systems at the three reactors, and heavily damaged other facilities at the Fukushima plant on the northeast coast.

Prosecutors had sought five-year prison terms for ex-Tepco Chairman Tsunehisa Katsumata, 79, and two former vice presidents, Ichiro Takekuro, 73, and Sakae Muto, 69.

More than 10,000 evacuees have filed about 30 civil lawsuits in total seeking damages from Tepco and the state. Several district courts have ruled that Tepco could have predicted and prevented the nuclear crisis.

Unlike criminal trials, civil trials generally examine the responsibility of a company, not individuals, and have less stringent demands for proof and evidence.

On March 11, 2011, the Fukushima plant was flooded by tsunami waves reaching 15.5 meters following the massive quake. Reactors 1 to 3 at the Fukushima plant suffered fuel meltdowns, while hydrogen explosions damaged the buildings housing units 1, 3 and 4.

The former executives were indicted for negligence that allegedly resulted in the deaths of 44 people, including patients who were forced to evacuate from a nearby hospital, as well as injuries suffered by 13 people — including by Self-Defense Forces members — as a result of the hydrogen explosions.

The trio pleaded not guilty, arguing that the tsunami was unforeseeable and that the meltdowns would have occurred even if they had implemented preventive measures.

The prosecution claimed that the top executives should be held criminally responsible because they could have predicted tsunami of the height that hit the Fukushima plant.

The court-appointed attorneys who acted as prosecutors said they would consider appealing the ruling.

According to the prosecutors, the executives were present at meetings where experts warned of massive tsunami that could hit the Fukushima coast.

A Tepco internal study, based on a 2002 report by a government panel, concluded that a wave of up to 15.7 meters could hit after a magnitude 8.3 quake and thus would surpass the 10-meter elevation of the site where major facilities were located. The findings were reported to Tepco executives including Muto in June 2008, according toa written statement from a former Tepco executive. That executive claimed that his boss abruptly postponed tsunami prevention measures at the Fukushima No. 1 plant in 2008. The statement was read during a court hearing.

In the statement, Kazuhiko Yamashita, who was in charge of taking measures against tsunami, said the three executives had approved plans to carry out tsunami safety measures in March 2008. But in July the same year, according to Yamashita, the trio shelved the plans, saying it would be difficult to convince the government and local residents of the power plant’s safety and that the move could fuel calls for halting operations. Yamashita’s statement supported arguments by the attorneys serving as prosecutors that the defendants shelved measures to protect the plant despite having recognized the necessity for such measures.

Katsumata, Muto and Takekuro were the only people facing criminal persecution in relation to the nuclear disaster.

Later on Wednesday, Tepco said in a statement that it is "aware of the ruling" but "will refrain from commenting on the criminal lawsuit." The utility also offered "a heartfelt apology to all related parties, in particular residents of Fukushima Prefecture, for causing great trouble and anxiety."

The trial started in June 2017 after a judicial review panel comprising ordinary citizens ruled that the former executives should be indicted. Initially, prosecutors twice declined to proceed with the case, citing insufficient evidence and a slim chance of conviction.

A total of 37 hearings were held for the trial, during which more than 20 witnesses, including current and former Tepco officials as well as earthquake and tsunami experts, were questioned.

According to government data, more than 31,000 people who evacuated from their homes in Fukushima are still living outside the prefecture.

Following the announcement of the court’s ruling, the prosecutors told reporters that they had done their utmost but failed to prove negligence of the trio.

Shozaburo Ishida on the prosecution’s side argued that the judges favored the government’s stance on nuclear power. He also criticized the court’s rationale that nuclear power companies are not required to ensure complete safety.

(Published by The Japan Times, September 19 2019)