Kobe Steel Develops Capsules to Dispose of Unexploded Ammunition; Estimated 1,900 Tons Still Remain in Okinawa Pref.

The Yomiuri Shimbun

13:07 JST, April 15, 2025

Kobe Steel Ltd. has unveiled capsule-type blast-proof containers it developed to dispose of unexploded ammunition more efficiently in Okinawa Prefecture.

The containers have a dual structure using high-tensile-strength steel and can endure explosions inside of them.

Using the containers can reduce the area from which residents must temporarily evacuate when disposals take place to less than 10% of the current level.

In the morning on March 25, personnel of the Ground Self-Defense Force disposed of unexploded ammunition by using the blast-proof container in Nanjo, Okinawa Prefecture.

The work used a nose fuse for naval gun shells measuring five inches (12.7 centimeters) in diameter. This is the most common type of unexploded ammunition found in the prefecture.

The GSDF personnel destroyed the nose fuse inside the container, and the work was finished in about 40 minutes.

People within a radius of 88 meters usually need to evacuate when this kind of work is being done. When the blast-proof container is used, the radius is reduced to 25.5 meters, a more than 90% decrease in area.

Also, the length of time to complete the detonation work can be shortened.

According to the Okinawa prefectural government, it is estimated that about 1,900 tons of unexploded ammunitions dropped or shot during the Pacific War still remain in the prefecture.

Even now, at least one piece of unexploded ammunition is found per day. It is estimated that it will take 70 years until all the unexploded ammunition can be disposed of.

Kobe Steel said that it is possible to develop other types of blast-proof containers that can handle ammunitions other than five-inch naval gun shells.