The Chemical Weapons Convention (CWC), which came into effect in April 1997, and the Memorandum on the Destruction of Japanese Discarded Chemical Weapons in China, signed on 30 July 1999, required Japan to dispose of an estimated 700,000 abandoned chemical weapons (Japanese estimate).
1997年4月，《化学武器公约》生效，1999年7月30日《销毁日本在中国遗弃化学武器备忘录》签署，日方估计需要处置的遗弃化学武器有70万枚。