On Sept. 29, 2024, Japanese officials will evacuate 1,400 people and remove a World War II-era shell discovered last year at a sewerage system construction site in Naha city, Okinawa. (Naha city)

CAMP FOSTER, Okinawa — Okinawa prefecture’s capital city will evacuate 1,400 people next month while Japanese troops disarm and remove a suspected U.S. bomb left over from World War II.

Workers found the 551-pound ordnance on Dec. 12 at a sewage system construction site in Naha’s Shuri district, according to the city’s website.

Members of the Japan Ground Self-Defense Force’s 101st Explosive Ordnance Disposal Unit will dig around the shell approximately 20 feet deep and 10 feet wide, then remove the fuse, the city said.

The evacuation is expected to begin at 8:50 a.m. Sept. 29 and conclude at 9:45 a.m., the city’s website states. Shuri High School, Okinawa Technical High School and Matsushima Junior High School will be open to the evacuees.

City and fire department officials will evacuate buildings within a 928-foot radius of the bomb, including 1,400 people in 470 households and 80 businesses, according to the city’s website.

Police will restrict traffic and the skies up to about 2,560 feet above will also be restricted, the website states. The operation is expected to conclude at around 2 p.m.

“We cannot start the operations if someone is within the evacuation area,” a spokesman from Naha’s Disaster Prevention Division said by phone Tuesday.

The disarmed shell will be stored at a prefecture facility until it’s detonated at sea, a Self-Defense Force spokesman said by phone Tuesday.

“It is not possible to remove the shell as it is, because it is very dangerous since it has the fuse in it and might explode,” the Disaster Prevention Division spokesman said.

Some Japanese government officials are required to speak to the media only on condition of anonymity.

The shell’s position in an extremely narrow and heavily populated area delayed its removal.

“Usually, we build something like a sand mountain covered with metal plates over the shell before removing it, but we don’t have the space to do so,” the Disaster Prevention Division spokesman said.

Because heavy machinery won’t fit in the space around the bomb, the city decided to dig a hole around it.

“We have to consider many things to not affect buildings surrounding the place and also we have to reconduct magnetic surveys after digging,” the spokesman said.

Approximately 2,000 tons of ordnance remains undiscovered out of 10,000 tons dropped on the island during the Battle of Okinawa, according to the prefecture’s General Bureau website.

Crews disposed of nearly 22 tons of unexploded ordnance between April 1, 2023, and March 31.

In June, authorities detonated three shells believed to be left over from World War II on an island just southeast of Naval Base White Beach.