Photo/Illutration The site of a massive landslide in Atami, Shizuoka Prefecture, on July 7 (Wataru Sekita)

A recent landslide at a seaside resort city close to Tokyo prompted the land ministry to consider introducing a system of accountability to track waste soil produced at construction sites and where it ends up, sources said.

Landfill used in a section of the steep mountainside of Atami in Shizuoka Prefecture swept away in the July 3 mudslide following torrential rains is increasingly being viewed as a major factor in the disaster that claimed 21 lives. Eight people remain missing.

There is no law in Japan governing the management and disposal of surplus soil.

The absence of legal regulations has led to the use of waste soil from construction sites nationwide that contributed to landslides in some cases.

A system that makes it possible to trace how waste soil is used would go a long way to prevent illicit disposal, the sources said.

In the Atami disaster, a construction company is suspected of having trucked in far more dirt and earth than it initially reported it would transport when applying for a permit for construction of a landfill from the Atami city government.

The land ministry is expected to conduct a demonstration experiment on the planned system during a public works project awarded by the central government.

An estimated 290 million cubic meters of waste soil was produced at construction sites across Japan in fiscal 2018 from tunneling and other work, according to ministry data.

Nearly half of it was transported elsewhere. But confirming whether the surplus soil was handled properly and moved to a secure location remains a challenge because such loads typically pass through multiple temporary storage areas, making it difficult to track.

Under the proposed new system, each vehicle transporting soil will be issued with an IC card to record information on the production site, temporary storage areas and disposal sites, as well as the time the soil was loaded. The data will then be available on the smartphones of operators.