DISCLAIMER

The following is a staff memorandum or other working document 
prepared for the members of the Advisory Committee on Human
Radiation Experiments.  It should not be construed as representing
the final conclusions of fact or interpretation of the issues. 
All staff memoranda are subject to revision based on further 
information and analysis.  For conclusions and recommendations of
the Advisory Committee, readers are advised to consult the Final
Report to be published in 1995.


                                             TAB N

MEMORANDUM

TO:       Members of the Advisory Committee on Human Radiation
          Experiments

FROM:     Advisory Committee Staff

DATE:     August 31, 1994

RE:       Permissible Doses Conference held at Chalk River,
          Ontario, September 1949

Over the years a number of conferences among representatives of
the United States, Canada and the United Kingdom have been held
at Chalk River, the site of Canadian nuclear laboratories.

The conference held in September 1949 was crucial in arriving at
an agreement on the basic parameters for developing safety
standards for radiation exposure. 

The document enclosed, provided to us by the Institute for Energy
and Environmental Research, is a summary of  that conference by
its secretary, G.E. McMurtie. It provides a detailed description
of the issues raised and the agreements reached.

The report is quite detailed and at times technical. However,
even a brief skimming allows one to contrast the discussion of
safety issues in 1949 with modern discussions. The list of topics
covered also provides an overview of the many areas in which
standardization was needed in order to develop broadly applicable
guidelines.

As a guideline to reading, the topics covered are:

1. Standard  Man                                       4
     a. Mass of Organs                                 4
     b. Chemical Composition                           6    
     c. Applied Physiology                             7
          (i) Water Balance
          (ii) Respiration
          (iii) Duration of Occupational Exposure
          (iv) Duration of "Lifetime" for Non-occupational 
               Exposure
     d. Standardized Terminology                       8
     e. Retention of Particulate Matter in the Lungs   8


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2. Relative Biological Efficiency                      9
     a. Beta particles
     b. Protons
     c. Alpha Particles
     d. Fast Neutrons
     e. Slow Neutrons

3.  Permissible exposure to External Radiation         11
     a. Whole body, long continued exposure
     b. Whole body, single exposure
     c. Hands, long continued exposure
     d. Head, long continued exposure

4. Permissible Exposure to Internal Irradiation        13
     Group I  (Radium, Radon, Uranium, Plutonium, 
               Thorium, Polonium)                      15
     Group II (Fission Products)                       18
     Group III (H 3, C 14,  Na 24, P 32, S 35, A 41, Sr 89, Sr 90, 
                I 131, Co 60)                          19


     a. Amount of radioisotope permitted fixed in the body
     b. Concentration of radioisotope permitted in inspired air
     c. Concentration of radioisotope permitted in drinking water


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