ENCLOSURE IV
UNITED STATES
ATOMIC ENERGY COMMISSION
WASHINGTON 25, D. C,
1 June 1957
Honorable Chet Holifield
Chairman, Special Subcommittee
on Radiation
Joint Committee on Atomic Energy
Congress of the United States
Dear Mr, Holifield:
Your letter of 31 May 1957 requests a letter on an unclassi-
fied basis giving: (a) an estimate as to year-to-year fission
yield and total yield put into the atmosphere by atomic weapons
from all sources;
} a list of weapons test series conducted by
each country; and
(c)
a listing of the number of explosions which
have taken place country-by-country and year-by~year,
As to total yield and total fission yield released by tests
to date either in gross or by nation, this information has
security implications which preclude my giving it as unclassified
data,
Various unclassified estimates which do not reveal such
totals have been made as to the amount of fission debris making
its way into the stratosphere,
One such estimate is that given
on pages 952 and 954 of the attached report, "Current Research
Findings on Radioactive Fallout," by Dr. Willard F, Libby.
Information as to U, 8. test series and the number of shots
in each is contained in the following table:
Name of Series
TRINITY
CROSSROADS
SANDSTONE
GREENHOUSE
RANGER
BUSTER/JANGLE
TUMB LER/SNAP PER
IVY
UPSHOT/KNOTHOLE
CASTIE
THAPOT
WIGWAM *
REDWING
PLUMBBOB
Date
_ 1945
1946
1948
1951
1951
1951
1952
1952
1953
1954
1955
1955
1956
1957
No,
of Shots
1
2
3
4
5
7
8
2
11
*
14
1
*
L**
* The number of shots in CASTLE and REDWING is still classified.
**Only one shot to date,
-4.
Enclosure IV