Japan and China have signed an agreement whereby Japan will dispose of chemical weapons it's army left behind in China at the end of World War II in 1945. There are between 700,000 and two million weapons,  loaded with chemicals, involved. The Japanese were using World War I era chemical weapons (mustard gas, phosgene, lewisite, hydrogen cyanide, and diphenyl cyanarsine). The decaying inventory consists of artillery and mortar shells, bombs and grenades. Some are buried, others are in decaying warehouses. The Japanese have long denied any responsibility for their abandoned chemical weapons.