UMPLASSIFIEA
dismiss them as likely due to chance, even in the many
cases in which the numberof workers understudyis so
small that statistical significance would be difficult to
studies are unduly shaded toward reassurance rather
deaths was extreme. Nuclear weapons workers and the
public alike may be falsely reassured by the DOE’s
follow-up of such leads and other methods ofanalysis
of the same data can yield important findings that
would otherwise not come tolight but may be viral.
The Task Force summarized reported trends or sug-
achieve unless the excess of observed over expected
emphasis, in repeated statements, that total death rates
and cancer death rates among nuclear weaponsplant
workers are usually lower than in the U.S. population
at large.
There are, however, alternauve ways of examining
the data, though they are notreflected in DOEstudies.
Comparisons of Standardized Mortality Ratios (SMRs)
for cancer among nuclear weapons plant workers with
the SMRs for other diseases or for total deaths may
suggest excess cancer risks. (An illustrative example is
presented in Table 2, Appendix F.) If specific data on
radiation exposures of workers were available, more
sophisticated analyses of this type would be possible.
A second problem is presented by the almost exclusive reliance of the DOE studies on death rather than
iliness, mortality rather than morbidity, as the health
outcome examined. Mortality studies are admittedly
cheaper and easier than studies of disease incidence.
Yet many adverse health outcomescan be ascertained
far sooner duringlife; mortality studies eliminate from
consideration virtually all adverse health effects which
may berelated to radiation exposure but which will not
or have not yet caused death. This is especially true in
the case of cancer; many cancers are now treatable, and
some curable, and if life is prolonged or the disease
cured, mortality studies of nuclear plant workers will
not give a true picture of the frequency with which
cancer appears in this group. Furthermore, because of
the way in which death certificate informationis frequently coded, cancer deaths may be miscounted or
falsely attributed to some other disease category.
“Statistical Significance” and Fragments of Knowledge
“All too often,” one researcher has noted, “investi-
gators disregard a positive association between exposure and disease . . . because thefindingis notstatistically
significant .. . . A consequenceis that negative findings
can be guaranteed simply by doing studies of small
populations or bystratifying data so finely that it be-
comes impossible to obtain ‘statistically significant findings’ unless an extremely strong exposure effect is
present.” Another has pointed out that “a small insensitive study may rule out very strong effects.”
Repeatedly, our reviewers described studies in which
DOE investugators have dismissed findings because they
were notstatistically significant even if more than the
expected numbers of total cancer deaths, or deaths
from specific cancers, had occurred. Often the num-
bers in any one study were too small to test for meaningful effects. Consequently,the interpretationsin these
12
than toward vigorous, inquisitive exploration ofclues,
recognition of potential “sentinel” events or warnings,
and growing magnitudes of effect over time. Careful
gestions of excess rates of cancer (typically mortality
rates) associated with working in the nuclear weapons
industry at 14 sites, 11 in the U.S. and three in the
U.K. (See Table 1.) We identified findings where there
was cither a standardized mortality or incidence ratio
over one (and the occurrence ofat least 5 cases), or a
standardized ratio that was significandy higher than
expected,or a statistically significant increase in cancer
with increased radiation exposure.
Table 1 shows an increase in deaths from all lym-
phatic and hematopoietic cancers, non-Hodgkins
lymphoma, brain and central nervous system cancer,
prostate cancer and lung cancerin five or more of the
populations. In addition, there were four sites with
increases in bladder cancer deaths. These findings,
in our view, do not justify a policy of under-
interpretation, reassurance or premature dismissal.
The epidemiologic research on the nuclear weapons
industry lends itself to meta-analysis, a method involving the aggregation of results from similar but independentstudies. The lack ofstatistical power associated
with studying one small group of workers can be overcome by combining theresults from several other studies. Meta-analyses may thus produce findings which
were not apparentin any ofthe individual studics. Two
recent meta-analyses have been published by non-DOE
investigators. One combinedtheresults of seven previously published DOE and U.K. studies (only four
DOE studies had sufficiently specific radianon dose
data to be included) and identified a 50 to 80 percent
increased risk of leukemia mortality among higherexposed workers; the other found a consistent 15 per-
cent excess risk of brain cancer among 8 of 10 nuclear
weaponsplant worker cohorts compared with the U.S.
general population. DOEresearchers have begun to
conduct studies pooling data from different sites, but
continue to conclude that there is not “clear evidence
of adverse effects of low-level radiation by external
exposure.”
Secrecy, Monopoly and Power
From theearliest moments of the development of
the nuclear weapons production complex, secrecy has
been the most dominant and unvarying characteristic
of the process, “National security” has been invoked to
justify secrecy not only for the design of weapons, the
processes of manufacture and theresults of testing but
also for the data on radiation exposure and health
DEAD RECKONING
URCLASSIFIEE