Three former Tokyo Electric Power Co. executives are the first utility officials to face criminal charges over their role in the 2011 meltdown at the Fukushima nuclear plant.
The Associated Press reports that a court-appointed committee indicted former TEPCO chairman Tsunehisa Katsumata, vice president Sakae Muto and technical adviser Ichiro Takekuro on professional negligence charges.
The criminal complaint alleged that despite being aware of the plant's vulnerability to a tsunami as early as 2009, the three officials failed to implement steps to safeguard the facility.
The executives countered that they could never have predicted a tsunami of the magnitude that hit Japan's coast in the wake of a massive offshore earthquake in March 2011.
The tsunami flooded backup generators that were intended to cool the plant's reactors in the event of a power outage. Three reactors subsequently melted down in the worst nuclear disaster since Chernobyl in 1986.
A study released last year found that the reactors were built in an area at risk of flooding and blamed the meltdown on a "cascade of industrial, regulatory and engineering failures."
But proving guilt among the three executives could be difficult. The AP reported that prosecutors twice elected to drop charges against the trio prior to this week's indictment.
The head of the group that filed the original complaint, however, expressed optimism that the process could nonetheless uncover more details about the meltdown.
"I believe truths about the accident that we are not told of yet will be revealed in court, and that a fair ruling will be handed down to the defendants for their responsibility," Ruiko Muto told the AP.
About 100,000 nearby residents were displaced by the Fukushima disaster; experts believe that the cleanup process could take 50 years under even the most optimistic projections.