Page 86 - Marutas of Unit 731

“I Bomb—e I Bomb, a 20kg modi ed gas bomb with a capacity of 2 liters,

was perhaps the rst munition developed for the dissemination of a

bacterial liquid payload. Explosion of the bomb head upon impact with the

ground blew out the tail with ejection of the liquid ll. e bomb was tested

during 1937-1938 by static and drop trials from aircra. For the trials, the

bomb was lled to about 70 percent capacity with 0.1 percent fuchain, 2 to 5
percent starch solution, or noninfectious agents. A rectangular grid

100 x 500 meters, with either test papers or Petri dishes, dep ending upon the

ll, placed at 20 meter inter vals, was used for assessment of dispersion. In

winter, a background of snow was used as a means of evaluating the e ective

area of dispersion of the bomb contents. With a wind velocity of 5 meters
per second, an area of dispersion 10-15 x 100-150 meters resulted in case of

static explosion. When dropped from aircra, the bomb buried itself before

exploding, resulting in a deep funnel-shaped crater with little e ective

dispersion of the contents. Depth of the crater dep ended on the height of

release. Dropped from an altitude of 1,000 meters, a crater 0.5-1 meter in
depth resulted; from 2,000 meters a crater 1-1.5 meter in depth resulted; a

4,000-meter drop caused a crater 2.5-3 meters. Because of the tendency to

bur y itself before detonation, its small capacity and large percentage of duds,

the I Bomb was considered unsatisfactor y and was discarded.”