Three former executives of Tokyo Electric Power Co. pleaded innocent June 30 in the first criminal trial over the 2011 Fukushima nuclear disaster, saying they had no way of foreseeing the mega-tsunami that caused the accident.

The prosecution side, however, argued at the Tokyo District Court that the defendants were in positions to know about the dangers of such a disaster occurring at the Fukushima No. 1 nuclear plant but did nothing to prepare for it.

The former executives are charged with professional negligence resulting in the deaths of 44 people who were forced to evacuate from a hospital near the plant and the injuries of others.

Tsunehisa Katsumata, former TEPCO chairman, apologized for the triple meltdown, but he denied he was responsible for the disaster.

“I would like to offer fresh apologies for the serious accident and the extensive trouble experienced by people surrounding the plant and the broader public,” Katsumata, 77, said after the trial opened. “But I believe that it was impossible to foresee such a tsunami and accident back then.”

Ichiro Takekuro, 71, and Sakae Muto, 67, both former TEPCO vice presidents, also denied the charges.

The three are the first to stand trial over criminal responsibility concerning the Fukushima accident. But the trial almost didn’t happen.

The Tokyo District Public Prosecutors Office twice decided not to indict them, citing a lack of sufficient evidence.

The case went to independent judicial panels of citizens, who recommended mandatory indictments against the three. They were indicted in February 2016.

The magnitude-9.0 Great East Japan Earthquake and ensuing tsunami on March 11, 2011, knocked out power at the plant. With no way to cool the nuclear fuel, three of the reactors melted down.

Up to 160,000 people were forced to evacuate as radioactive substances leaked from the crippled plant. Those who died in the evacuation were mostly elderly people or patients already weakened from chronic illnesses.

At issue in the trial is whether it was possible for the accused to foresee a major accident resulting from the huge tsunami, which topped 15 meters at its highest point. Another issue is whether TEPCO could have prevented the accident by taking adequate measures to safeguard the plant.

In the indictment, lawyers acting as prosecutors contended that the three former executives failed to take proper safety precautions although they could have envisaged a gigantic tsunami swamping the plant and causing a serious accident.

The prosecutors noted that an in-house calculation at TEPCO produced “astounding results” in March 2008 that projected a tsunami up to 15.7 meters hitting the Fukushima plant. The height was calculated based on an updated prediction by a government agency.

They said a blueprint for constructing seawalls on the east and south sides of the plant was drawn up and presented to both Takekuro and Muto.

But such safeguard measures were never taken.

One prosecutor said the defendants were ultimately responsible for securing the safety of the plant.

Referring to Katsumata, the prosecutor said, “He attended a meeting on decision making and in effect gave directions and made policies.”

Katsumata was president in March 2008, when TEPCO made the projection of a possible 15.7-meter tsunami, prosecutors said. He served as TEPCO chairman from June 2008 until 2012.

The prosecutor said Takekuro and Muto were in a position to assist Katsumata.

Takekuro was deputy chief and later chief of the company’s nuclear power and plant siting division between 2004 and 2010. Muto also led that division.

“There is no way of predicting when a tsunami will hit, so they should have taken steps, even by shutting down the plant, when they were aware of the possibility of that happening,” the prosecutor said.

The prosecutors also said that Katsumata attended a February 2009 meeting in which the possibility was raised of a “tsunami up to 14 meters or so” striking the plant.

“The three were able to foresee the risks of the accident, and if they had fulfilled their duties and responsibilities properly, the accident would not have occurred,” the prosecutor said.

In a Diet investigation into the Fukushima accident, Katsumata testified that he “was not briefed on the result of the calculation (of a 15.7-meter-high tsunami).”

Takekuro and Muto, however, admitted that they had been informed.

More than 10,000 people across Japan signed petitions for criminal complaints against TEPCO, its executives and government officials that were sent to the Tokyo District Public Prosecutors Office and elsewhere.