An employee of Japan’s nuclear regulator lost work-issued smartphone containing highly sensitive contact information while traveling in China late last year.

Axar.az informs, citing Japan Times, the Nuclear Regulation Authority (NRA) said an employee lost the smartphone during a personal trip to China in November.

The device, which has not been recovered, contained the names and contact details of staff in charge of nuclear security — information that is not publicly disclosed due to its high level of confidentiality.

According to the authority and other sources, the employee believes the phone was lost on Nov. 3 while passing through security at an airport in Shanghai.

The affected department is responsible for safeguarding nuclear materials at domestic facilities, including measures to prevent terrorism and theft. As a rule, the identities and direct contact details of personnel involved in nuclear security are kept confidential to minimize security risks.

To ensure a rapid response to emergencies such as nuclear accidents or major earthquakes, certain NRA staff are issued disaster-prevention smartphones and are required to carry them at all times.