At the end of World War II, the Imperial Japanese Army left a number of unexploded shells filled with poison gas used as munitions. In the 2000s, when such artillery shells were discovered and retrieved from the seabed off the coastal town of Kanda, Fukuoka Prefecture, the central government issued an order to detoxify more than 3,000 such chemical agents. About three years ago, government officials announced they had completed the operation.

But reports and records that came to light in recent years show the government has hidden the fact that another unexploded ordnance with a chemical agent was later found under the sea. Moreover, unbeknownst to residents, a new facility has been constructed in Kanda where the disposal of unexploded poison gas shells is still taking place.

The Nishinippon Shimbun learned of the ongoing detoxification work from a 60-year-old independent researcher of abandoned artillery from Kitakyushu, who contacted the newspaper's investigative team.