ATTACHMENT 2

  
                           CONFIDENTIAL

              RADIATION EXPOSURE IN THE UNITED STATES
                    -- URANIUM MINING INDUSTRY

     There are approximately 300 mines mining uranium ore of
various types on the Colorado Plateau.  The greatest production
of uranium ores presently (1951) comes from the State of
Colorado, with sizeable quantities also mined in Utah, New Mexico
and Arizona.  New discoveries, but as yet undeveloped, have been
reported in Montana and Wyoming.  There are eight mills engaged
in the processing of the uranium ores, which  produce as their
final products uranium oxide and vanadic acid.  The uranium oxide
is shipped to other establishments controlled by the AEC for
refining and subsequent separation of the isotopes.  It is
estimated the industry employs between 2000 and 3000 persons.

Hazards Involved

     The miners are exposed to external radiation, radon gas, and
a high silica dust containing an undetermined amount of
radioactivity.  In addition to these factors, it appears that the
uranium and vanadium which are contained in the dust are of
toxicologic importance, and also that the matter of internal
radiation due the inhalation of radioactive dust must be
considered.

The mill workers are exposed to the following environmental
materials:

     (1)  uranium and vanadium containing dust

     (2)  fumes and dusts of the isolated uranium and vanadium

     (3)  radon gas (of little significance due to dilution)

     (4)  external radiation (very low level)

     (5)  internal radiation due to inhalation of radioactive
          dust

Mine Hazards

     During the 1950 and 1951 seasons, 132 samples for radon gas
in 48 mines gave a median level of 3100 micromicrocuries per
liter.  The established maximum allowable concentration adopted
by the American Conference of Government 

				  1

Industrial Hygienists is 10 micromicrocuries for an 8-hour
exposure.  This median level is 310 times the accepted M.A.C. 
The highest value encountered in the survey was 80,000
micromicrocuries per liter.

     It is important to note that in German mines containing a
median level of 1500 micromicrocuries of radon per liter,
definite pathology was found.  There was an attack rate of about
1% per year of lung carcinoma and 50-70% of the deaths of the
workers in these mines were due to a primary cancer of the upper
respiratory system.

     Measurements of external radiation gave results varying from
25 to 176 mr/day.  However, the meaning of these figures is
obscure as a number of problems exist in the mines which
interfere with radiation measurements.

     Dust control in the mines has been fairly good due to
widespread use of wet drilling and because of the fact so many of
the mines are so-called wet mines.  Dust concentrations ranged
from 5 to 20 million particles per cubic foot, and it is believed
that in view of our present knowledge the silicosis problem in
the mines is not too acute.

     Evaluation of internal radiation to inhalation of
radioactive dust has not been made.  The problem is recognized,
however.

Mill Hazards

     As pointed out earlier, the mills do not have the problems
of radon gas and external radiation which are important in the
mines.  However, the dust hazard and internal radiation hazard
are recognized and are awaiting evaluation

Medical Findings

     The uranium level in the urine of workers in the mines and
in the mills has been determined.

				   2

     The median value for the mine workers is in the neighborhood
of 2.5 micrograms per liter and for the mill workers .4.2
micrograms per liter.

     There have been no medical findings relatable to uranium
exposures, although the exposures are high. This is not
surprising since the majority of persons exposed have been
working for a period of less than five years.  From experience in
the European mines, it is indicated that a minimum of ten years
would be required for the development of lung cancer.

     Immediate attention has been given to the high concentration
of radon in the mines.  A tentative goal of 1000 micromicrocuries
of radon per liter is being established as the maximum working
level.  Work has indicted that with proper ventilation, this goal
can be reached.

				3