Govt. Premises in Tokyo’s Kasumigaseki to Receive Soil from Fukushima, New 5-Year Roadmap Reveals

The Yomiuri Shimbun

20:00 JST, August 26, 2025

Nine locations on the grounds of central government offices in the Kasumigaseki area of Tokyo have been selected to receive soil with low levels of radiation removed during decontamination work following the 2011 accident at the Fukushima No. 1 nuclear power plant as early as next month, according to a government roadmap approved Tuesday.

The five-year roadmap, officially approved at a meeting of relevant ministers, is a collection of measures to be taken for the disposal of all the removed soil outside Fukushima Prefecture to go ahead.

At the ministers’ meeting held on Tuesday, Chief Cabinet Secretary Yoshimasa Hayashi said, “The government will make every effort to realize the final disposal of the soil outside the prefecture.”

Currently, about 14 million cubic meters of removed soil is being temporarily stored in an area spanning the two prefectural towns of Okuma and Futaba near the nuclear power plant. All of the soil is legally required to be disposed of outside the prefecture by March 2045.

In order to reduce the amount of soil to be disposed of, the government plans to reuse the 75% of the soil with radioactivity of 8,000 becquerels or less per kilogram in road embankments and land development projects. The radiation dose a person would receive from this portion of soil would not exceed 1 millisievert per year, the maximum public exposure allowable under international safety standards.

According to the roadmap, about 80 cubic meters of the soil with low radioactivity will be transported to nine locations in the Kasumigaseki district, including the grounds of the Central Common Government Offices, which house government ministries and agencies such as the Economy, Trade and Industry Ministry and the Foreign Ministry, in or after September. The soil will be added to flower beds and embankments within the premises.

A project planned by the Environment Ministry to reuse the soil on government-owned land outside the prefecture has fallen through due to opposition from local residents.

In July, the government transported about 2 cubic meters of the soil to the Prime Minister’s Office to reuse it in the front garden.

In the roadmap, the government set out its stance of proactively accepting the soil and plans to expand reuse not only in the Kasumigaseki district but also in other regions where local offices of the central government are located.

Meanwhile, no prospective sites have emerged for the disposal of the remaining 25% of the soil, which has a radioactivity of more than 8,000 becquerels per kilogram.

The roadmap states that the government will begin selecting and investigating candidate sites for final disposal of the soil around 2030. It says the Environment Ministry will discuss such matters as the conditions for candidate locations at an expert panel to be established in autumn.

The government is believed to be aiming at promoting public understanding regarding the safety of the soil, among other issues, and realize its final disposal.