Photo/Illutration New equipment for unexploded ordnance disposal called the “explosion-proof container” in Ginowan, Okinawa Prefecture, on Jan. 28 (Takashi Watanabe)

GINOWAN, Okinawa Prefecture--A new method has been introduced for the central government disposing of unexploded ordnance left behind from the bloody Battle of Okinawa near the end of World War II.

The central government hopes the method, which uses a capsule-type container, will greatly reduce the evacuation scope of nearby residents in case of an accidental explosion during the work.

The new method was introduced at the Ginowan seaside park site on Jan. 28.

The Ground Self-Defense Force stored unexploded ordnance in a special steel container, manufactured by Kobe Steel Ltd., in the back of a truck.

The container is about 1 meter in diameter and is called an “explosion-proof container.” The GSDF personnel then remotely destroyed the fuse.

The unexploded ordnance were found at the park in December 2023 during construction work.

The physical sensation of noise and vibration were “considerably reduced” with the new method, said an official of the Cabinet Office’s Okinawa General Bureau. Officials will further verify the effects in the future.

Until now, unexploded ordnance had been eliminated in a shelter surrounded by a protective barrier called a “liner plate,” which was up to 3 meters in diameter and 6 meters high.

Because the top of the protective barrier was open, there was a risk of flying debris in the event of an accidental explosion.

The most commonly discovered 5-inch U.S. Navy ship shells will be processed using the new method.

A trial period for the method will continue until March.

After that, it is expected that the evacuation area for residents will be reduced from the current 88-meter radius to an approximately 25-meter radius, which is expected to reduce the impact on residents’ daily lives and economic activities, as well as the administrative burden.

During the war, approximately 200,000 tons of ammunition were used in what was known as the “typhoon of steel” of U.S. naval gunfire, leaving behind large quantities of unexploded ordnance.

According to the prefectural government’s estimates, the U.S. military and residents did away with about 5,500 tons before Okinawa’s reversion to Japan in 1972.

After the return, the SDF destroyed about 2,100 tons, but nearly 1,900 tons remain.

About 17 tons have annually been eliminated in recent years.

“By simple arithmetic, it will take over another 100 years” to dispose of all unexploded ordnance, a prefectural official said.

Furthermore, new unexploded bombs are being created due to exercises conducted at U.S. military bases in the prefecture.

Since Okinawa’s reversion to Japan in 1972, there have been 18 cases of personal injury caused by unexploded ordnance, resulting in seven deaths and 59 injuries, according to the prefectural government.

In 1974, an explosion during sewer construction near a kindergarten in Naha killed a toddler and three workers and seriously injured 34 others.

In 2009, a 250-kilogram U.S. military bomb exploded while excavation work was being carried out with heavy machinery at a water pipe construction site in Itoman in the prefecture.

A worker was seriously wounded and about 100 windowpanes at a nearby nursing home were shattered.

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