The Epidemic Prevention and Water Purification Department was a department of the Imperial Japanese Army from 1936 to the dissolution of the Army in 1945. While its public mission was to prevent the spread of disease and monitor water supply, several field armies also assigned units the mission of manufacturing biological weapons.[1] Many units also performed unethical human experimentation, such as Unit 731, in which thousands of prisoners of war and civilians were tortured to death over the course of years.