A Japanese court on Thursday ruled that three former executives for Tokyo Electric Power Company were not guilty of professional negligence in the 2011 Fukushima meltdown. It was the only criminal trial in the nuclear disaster that has kept tens of thousands of residents away from their homes because of lingering radiation contamination.

The court said ex-TEPCO chairman Tsunehisa Katsumata, 79, and two former executives were also not guilty of causing the deaths of 44 elderly patients whose health deteriorated during or after forced evacuations from a local hospital.

The executives were charged with failing to foresee the tsunami that struck the plant after an earthquake and for failing to take preventive measures that might have protected the Fukushima Dai-ichi plant on Japan’s northeastern coast.

Katsumata and co-defendants, Sakae Muto, 69, and Ichiro Takekuro, 73, pleaded not guilty during the trial’s opening session in June 2017. They said predicting the enormous tsunami was impossible.

Three of the plant’s reactors had meltdowns after the magnitude 9.0 earthquake and tsunami on March 11, 2011, spreading radiation into surrounding communities and into the sea.

Prosecutors in December demanded a five-year prison sentence for each executive, accusing them of professional negligence for not taking sufficient measures to guard against the threat of a tsunami despite knowing the risks.

Hiroyuki Kawai, a lawyer representing the more than 5,700 Fukushima residents who filed the criminal complaint to prosecutors, said before the ruling that he expected the legal battle to last about a decade because the losing side will appeal.