196
MAJOR ACTIVITIES
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their accidental exposure to fallout from a March 1, 1954, test,? the people were found to be generallyiin good health and their Nein
was satisfactory.
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A few residual changes from beta burnsstill were apparent in the e
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skins of some people.
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Otherwise, there has been no outward evideng, $4
of any radiation effects.
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There have been no symptomsordisease, ©. pi
related to radiation effects.
Incidencé of diseases was about the“2
same as in unirradiated Marshallese people.
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The children are groy, <F
ing and developing at rates consistent with off-island controls,
2
No long-term effects of radiation have been observed. Body *
burdensof certain radioisotopes apparently are well below accepteg “*
tolerance levels.
4
Three deaths have occurred in the irradiated group, but were no,
associated with radiation effects. This death “rate appears to be ~
about the same as in the unexposed Marshallese people.
n
Operation Hardtack: Nevada Phase
Operation Hardiack Phase IJ was conducted at the Nevada Test
Site, August 25-October 31, 1958.
.
_ Preliminary data on external gamma radiation exposures in communities around the Nevada Test Site resulting from nuclear weapons
tests in the Hardtack-Phase I] series do not substantially change the
figures reported in the Plumbbob series,® since the estimated highest
exposure was less than 0.1 roentgen. A complete summarization
of all these data will be made when the evaluations are completed.
The highest concentration of airborne radioacitivity measured offsite during Hardtack-Phase If was about 8.4 x 107? microcuries per
cubic meter averaged over a 24 hour period at Lathrop Wells, Nev.
Relatively high concentrations also were observed during the following
week. The principal point of health in evaluating such concentrations in theair is the potential radiation doses to the lungs. The best
estimates are that the total radiation dose to the lungs from inhalation of radioactive debris at Lathrop Wells would not exceed that.
received every few weeks from naturally occurring radioactive substances in the air. Since several nuclear detonations occurred in this
period of time, it is not possible to state the exact contributions cach
detonation made to the observed. concentrations in theair.
The highest fission product radioactivity measured in a water
supply was at Reed, Nev., amounting to 8.9 x 107" microcuries per
? Earliest examinations were made at 6 months, ) year, 2 years, and 3 years after their exposure and the
reports have been published. See pp. 132-135, Twenty-second Semiannual Report (January-June 1957).
§ See pp. 281-284, Twenty-third Semiannual Report ta Congress (July-December 1957),
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