Seven decades after thousands of "balloon bombs" were let loose by the Imperial Japanese Army to wreak havoc on their enemies across the Pacific, two forestry workers found one half-buried in the mountains of eastern British Columbia.

A navy bomb disposal team was called and arrived at the site Friday in the Monashee Mountains near Lumby, B.C.

"They confirmed without a doubt that it is a Japanese balloon bomb," said RCMP Cpl. Henry Proce.

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"This thing has been in the dirt for 70 years .... There was still some metal debris in the area (but) nothing left of the balloon itself."

The forestry workers found the device Wednesday and reported it to RCMP on Thursday.

Proce, a bit of a history buff himself, accompanied the men to the remote area and agreed that the piece appeared to be a military relic.

The area was cordoned off and police contacted the bomb disposal unit at Maritime Forces Pacific.

It was a big bomb, Proce said. A half-metre of metal casing was under the dirt in addition to approximately 15 to 20 centimetres sticking out of the ground.

"It would have been far too dangerous to move it," Proce said. "They put some C4 on either side of this thing and they blew it to smithereens."

Between November 1944 and April 1945, the Imperial Japanese Army released more than 9,000 bomb-bearing balloons.

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Assembled from bark and rice paper, in some cases by school children, the balloons were loaded with hydrogen and attached to a chandelier-type structure loaded with sandbags and incendiary bombs, said Andrew Burtch, director of research at the Canadian War Museum.

This one would have been equipped with two large bombs and four smaller ones that may have exploded on landing decades ago.

"It would go up into the jet stream and get pushed across the Pacific over the course of two or three days," he said.

"They were launched from beaches in Japan with the objective of creating havoc in North America, which had until then been relatively untouched by the war."

As hydrogen depleted, the balloons would lose altitude so the devices were rigged with barometers and timers to drop sandbags as necessary to keep the balloon aloft.

It is estimated that at least 1,000 made it over the ocean and as far inland as Michigan and Manitoba.

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"It's quite an ingenious device," Burtch said. But "in the end, not too effective."

There were no deaths reported in Canada, but an Oregon Sunday school teacher and five teens were killed by one in 1945.

Canadian Navy Lt. Paul Pendergast said the bomb disposal unit is called about once a month for suspect objects.

"Sometimes they're a souvenir someone kept from World War II, and they may be inert or they may be live," he said.

When they pose a hazard, the items are blown up on site.

Metals rings and other part of the device were found in the area and Proce said he hopes they will be put on display at the museum in Lumby, 460 kilometres east of Vancouver.