Undiscovered World War II Bomb Spontaneously Explodes at Japanese Airport

This image from video taken from a helicopter of Miyazaki Prefecture shows part of a damag
Miyazaki Prefecture via AP

Japan’s Miyazaki Airport shut down for a day, canceling dozens of flights, after a World War II-era bomb exploded underground on Wednesday morning.

Japanese media described the bomb as a “dud shell” dropped by the United States military during World War II that had been long buried under a paved taxiway for airplanes. Japan is littered with undetonated munitions, many of them underground as reconstruction of the country followed its surrender in the war.

The government has not reported any casualties in connection to the massive blast, which left a three-foot-deep hole and occurred minutes after several airplanes used the taxiway.

“The Japan Ground Self-Defense Force said the explosive was a 250-kilogram bomb from World War II and is investigating how it exploded,” Japan’s Kyodo News reported of the incident. “The Japanese government said Wednesday a U.S.-made bomb was the cause of the explosion.” Kyodo noted that four planes had been over the undiscovered bomb shortly before it exploded.

The Yomiuri Shimbun, another Japanese newspaper, reported that airplanes were moving directly above the bomb two minutes before it exploded.

Video of the incident shows a massive vertical blast of asphalt shooting up from the airport, forcing the shutdown of the facility.

The Yomiuri Shimbun reported that government experts believe the munition was buried about three feet under the surface, thus explaining the depth of the hole it left behind, and as of Thursday have refilled the hole to allow for the reopening of the airport. Airport officials told the press late Wednesday that they had conducted a search of the entire premises of Miyazaki airport looking to find more potential bombs, but did not find any.

“We believe that an underground survey has been conducted, so it is unlikely there are other unexploded bombs,” the head of the airport office told reporters. “Considering the balance between convenience [and safety], we will resume operations as soon as the collection of flying debris and backfilling [of the hole] are completed.”

Government officials indicated that the shocking, and potentially deadly, incident has prompted an investigation into records of similar World War II-era bombs that may be buried elsewhere in the country to ensure that such an incident does not happen again.

The Japanese newspaper Asahi Shimbun noted that the discovery, and sometimes explosion, of undetonated bombs from the World War II era is not unheard of in the country; around 20 instances similar to the one on Wednesday have been documented since the war ended. Miyazaki Airport is particularly vulnerable to such findings, however, as it served as a Navy air base for Imperial Japan and thus was heavily bombarded towards the end of the war. Asahi Shimbun detailed several incidents in which American World War II-era bombs were found at the airport prior to this week:

In June 2021, an unexploded U.S.-made bomb, estimated to weigh one ton, was discovered during asphalt resurfacing work at the airport’s parking apron.

In June 2011, a worker conducting pipework in the green area next to the runway found an undetonated U.S.-made 50-kilogram bomb.

In November that year, another unexploded U.S.-made bomb, weighing 250 kg, was discovered underground beside the runway during the installation of runway lights.

Asahi also listed an incident in 2009 in which a bomb was found undetonated outside of the confines of the airport, but in a nearby residential community. None of these incidents involved the actual explosion of any of the bombs.

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