“Under the Chemical Weapons Convention, Japan must clean up by 2007 poisonous agents it abandoned in China. Japan says about 700,000 bombs armed with chemical weapons remain in China, mostly in the northeast.
Tokyo has spent about 31.6 billion yen (US$263 million) for the cleanup project there over the past four years.
Japan stockpiled large amounts of chemical weapons in China during the 1930s but has acknowledged using only irritant gas during World War II. Experts say Japan also used other kinds, including cyanide.
Japan produced about 7,000 tons of poison gas, mainly mustard gas and lewisite, an arsenic-based fluid that causes blisters.”
AP, March 8, 2003, Google-Cache.