One proposal called for Seiran aircraft to disperse disease agents and for infected submarine personnel to go ashore in a suicide mission. A larger force could have created an exceptional public-health and security crisis, even if a single boat's three aircraft would not by themselves decide the war. The scenario uses roughly 16-20 aircraft from six to eight submarines, including converted boats, rather than one I-400 acting alone. The operation never took place, and the danger depends on the possibility of multiple simultaneous outbreaks. Pathogens with different incubation and transmission patterns could have caused a crisis, but the proposal's success was never certain.
Notable Point · 56:39-1:03:18
The unexecuted biological-warfare proposal
A proposed I-400 operation envisioned biological warfare against the United States, illustrating the class's most disturbing potential use.