March 12, 1951

The results of an extensive analysis of the fission gases
and the attendant hazard to the surrounding population on
release after a 5 day holding period are as follows:

• 1. There is no danger from solid deposits on buildings
  or streets.
•  
• 2. If iodine can be trapped in the system, and the
  [gamma]-activity of Xe133 is manifested in skin exposure
  only, with a dilution of 20,000 cfm of air and a
  subsequent spreading of a factor of five, the
  continuous exposure is about twice tolerance.
  

It must be concluded tentatively that concentration of
gases and holding periods of a month or more are needed to guarantee
safety.

The full report on this subject is available in long-hand for
study. The calculations corroborate those made earlier by Dr. A. C.
Menius.