 Gases manufactured in Okunoshima were used more than 2,000 times against Chinese soldiers and civilians in the war in China in the 1930s and 1940s

Bacteriological weapons provided by Shirō Ishii's units were also profusely used.For example, in 1940, the Imperial Japanese Army Air Force bombed Ningbo with fleas carrying the bubonic plague.During the Khabarovsk War Crime Trials the accused, such as Major General Kiyashi Kawashima, testified that, in 1941, some 40 members of Unit 731 air-dropped plague-contaminated fleas on Changde.