COVERUPS AFTER THE WAR

Afterwar Coverups
Unit 731 was ordered to be destroyed as Japan prepared to surrender in early August 1945. Beginning on August 9, 1945, dynamite was used to try to destroy all the evidence of its germ warfare program. 
The leaders of Unit 731 were exempt from being put on trial because the United States wanted the Japanese findings about the effects of biological agents on soldiers and civilians for its own potential military use. Not only were the leaders of Unit 731 exempt from trial, they were also put on the American payroll. General Ishii Shiro was able to live without penalty until his death from throat cancer in 1959.
The Imperial Japanese Army also attempted to hide the ​gas production site at Okunoshima. While the Allied soldiers discovered the plant, the Americans soldiers dumped almost 5,000 tons of poison gas into the sea in 1946. 
Most members of Unit 731 end up with prosperous careers when the war was ended. 
Related Book

Unit 731- The Forgotten Asian Auschwitz

The Japanese invasion of China during the Second Sino-Japanese war has left a strong legacy of hate and disgust among many Chinese today. Much of the atrocities committed by the Japanese are now known to most historians. By far, the most despicable and forgotten act against humanity committed by the Imperial Japanese government was its covert biochemical weapons program. Euphemistically labelled as the "Epidemic Prevention and Water Purification Department" of the Imperial Japanese Army, the Japanese conducted a wide range of cruel and inhumane experiments on prisoners who were often innocent.