B. Failure to find any clinical evidence of persons harmed by persistent
radioactivity.

The effects of the atomic bombs on human beings were of three main types:

A. Burns, remarkable for (1) the great ground area over which they were
inflicted and (2) the prevalence of "flash" burns caused by the
instantaneous heat radiation.

B. Mechanical injuries, also remarkable for the wide area in which
suffered.

C. Effects resulting from penetrating gamma radiation. The effects from
radiation were due to instantaneous discharge of radiation at the moment of
explosion and not to persistent radioactivity (of either fission products
or other substances whose radioactivity might have been induced by
proximity to the explosions).

The effects of the atomic bombs on structures and installations were of two
types:

A. Destruction caused by the great pressure from the blast; and

B. Destruction caused by the fires, either started directly by the great
heat radiation, or indirectly through the collapse of buildings, wiring,
etc.

4. The actual tonnage of T.N.T. which would have caused the same blast
damage was approximately of the order of 20,000 tons.