Unit 731 was the Imperial Japanese Army's biological warfare unit. Allied
POWs were subjected to gruesome experiments. Its commander, General
Shiro Ikii, skated on war crimes charges because the United States wanted to use his knowledge for its fledgling biological warfare program. One of the
weirdest, and successful, bombs produced by Unit 731 was a plague bomb.
Survivors are suing the Japanese over this. More people died in Unit 731 than died in the Nazi death camps. There was a book written about it back in
the '90s. Another possibility, and real fear among policy makers in 1945, was
a possible kamikaze attack on San Francisco with plague bomb. Unlike the
Nazi death camps, very little is known about Unit 731.