The first test series at Eniwetok, Operation Sandstone (1948),
incorporated no formal radiobiological studies, but radiobiologists
visiting Bikini also made surveys at Eniwetok in 1948 and 1949. Then,
for a time, world events intervened. The detonation of an atomic device
by the U.S.S.R. in 1949 was followed in 1950 by the outbreak of the
Korean War, and these events produced a national mood oriented toward
national defense. By 1951, because events in the Pacific had interrupted
tests there, the Atomic Energy Commission had established a continental
test site in Nevada. In that year, too, tests were made at Eniwetok
preliminary to the detonation of the first thermonuclear device.
After 1951 each of the test programs had its radiobiological component.
In the Pacific, radiobiological surveys were associated with Operation
Ivy (1952), Operation Castle (1954), Operation Redwing (1956), and
Operation Hardtack (1958). A small field station, the Eniwetok Marine
Biology Laboratory, was established for use by scientists conducting
biological studies. Bikini was incorporated into the Pacific Proving
Ground in 1953, and new biological surveys were performed there in
connection with the tests of 1954 and later.
[Illustration: _The Eniwetok Marine Biology Laboratory. Monument at
right commemorates the battle for Eniwetok in World War II._]
In these years, 1951 to 1958, the U.S.S.R. was testing nuclear weapons,
as was Great Britain after 1952. Fallout from these contributed to the
total of man-made radioactivity potentially available to the
environments of the world.