An employee at Japan's nuclear safety agency lost his work phone containing sensitive information during a personal trip to China, Japanese media report.
The phone contained confidential contact details of staff involved in nuclear security work at the Nuclear Regulation Authority (NRA). The agency could not confirm if the data was leaked, reports say.
The incident comes as Japan attempts to revive its atomic energy programme, which has been stalled for more than a decade.
Japan ordered all its nuclear power plant reactors to be shut down in 2011 after a magnitude 9 earthquake and massive tsunami caused a meltdown at the Fukushima nuclear plant.
The NRA was formed after the Fukushima nuclear disaster to oversee nuclear safety, including the restarting of the country's reactors.
The NRA employee is believed to have lost his work phone on 3 November while undergoing a security check at a Shanghai airport on a personal trip.
He noticed the phone was missing three days later and, despite checking with the airport, did not recover it.
The NRA issues smartphones to certain employees so they can respond promptly to emergencies, the Asahi newspaper reported.
According to Kyodo News, the affected NRA department deals with protecting nuclear materials from threats like theft and terrorism at the country's facilities.
The NRA reported the incident to the country's Personal Information Protection Commission and has warned employees against bringing work phones overseas, local media reported.
This is not the first time that Japan's nuclear officials have made headlines for security lapses.
In 2023, an employee at the Kashiwazaki-Kariwa Nuclear Power Plant—the world's largest nuclear facility—lost a stack of documents after placing it on top of their car and driving off.
Last November, another employee at the Kashiwazaki-Kariwa plant was found to have mishandled confidential documents by making copies of them and locking them in a desk.
And this week, Chubu Electric Power, a nuclear plant operator in central Japan, said it might have used cherry-picked data during safety screenings for its nuclear plant.
The NRA has since suspended its review for Chubu to restart its reactors, citing the fabrication of critical inspection data, Reuters reported.
