More than 500 suspected bombs that may contain poison gas have been detected in waters around the port of Kanda, Fukuoka Prefecture, local port authorities said Friday.
The bombs were probably abandoned immediately after World War II.
Fifty-seven shells of this kind were found at the port in November 2000. Officials at a munitions factory located near the port during World War II are said to have thrown various weapons into the sea after Japan's surrender.
The Kanda office of the regional port management bureau said a previous survey using magnetic detectors identified the existence of some 700 metallic objects. Another probe using more sensitive equipment was conducted in July, officials said.
The latest survey showed that the 538 suspected bombs in question are similar in size and shape to the gas bombs that have already been found. Of these, 368 "definitely have the external shape of bombs, given their magnetic characteristics," officials said.
They added, however, that it is unclear whether they contain poison gas.
Fifty-seven abandoned bombs were found near the port in November 2000.
The Maritime Self-Defense Force collected 18 of these devices and confirmed that they contained toxic gas. The shells are currently kept by the MSDF at their office in Sasebo, Nagasaki Prefecture.
The remaining 39 are also believed to be gas bombs and are still underwater.
The government appropriated 2.3 billion yen in the fiscal 2002 budget for the survey and disposal of gas shells.
The Defense Agency has told the town government that pier-like structure should be built in waters near the port, and that a gas disposal plant should be erected atop it.