Katsumata was TEPCO chair when Fukushima Daiichi was hit by a magnitude 9.0 earthquake and tsunami in March 2011 and suffered triple meltdowns. He led the emergency response after the company’s then-president stepped down due to health problems and served until mid-2012.

He later became one of the defendants in high-profile criminal and civil lawsuits seeking TEPCO management’s responsibility over their alleged failure to anticipate the massive quake and tsunami and to take preventive measures.