January 29, 2024
This is an excerpt from the final submission by the Canadian Environmental Law Association to the Canadian Nuclear Safety Commission on the application to construct the Near Surface Disposal Facility at Chalk River, Ontario
Another issue not discussed in the EIS is the new evidence that radiation risks are greater than
currently acknowledged. This new evidence is from the International Nuclear Workers’ Study
(INWORKS) which comprises a number of meta studies of nuclear workers in the US, UK and
France. These meta studies are very large (>300,000 participants) which lends considerable
authority to their findings.
In more detail, in late 2015 and in subsequent years, the INWORKS studies examined associations
between low dose-rate radiation and leukemia/lymphoma76, solid cancers77, and circulatory disease.
Their radiation risk estimates were higher than current risk estimates. For example, in
the solid cancer study, the observed increase was 0.47/0.32 = 1.47, ie a 47% increase – a significant
amount. But for leukemia the increase was much greater. The more recent study on leukemia risks
(Leurad et al, 2021) found the increase in point estimates was 5.8 fold or 580%. This large increase
was driven mainly by the 11-fold increase in chronic myelogenous leukemia80 (“CML”) in older
workers81. The study on cardiovascular risks somewhat surprisingly reported brand new risks of
heart disease and strokes. These new risks and increased risks are not taken into account in official
risk estimates by regulatory agencies including the CNSC but they should be.
The INWORKS radiation studies remain pertinent as to whether a license should be given to CNL
for a number of other reasons, as follows. They:
a. provide strong evidence of a dose-response relationship between cumulative, chronic,
low-dose, exposures to radiation and leukemia.
b. confirm that radiation risks exist even at very low dose rates (average = 1·1 mGy per
year).
c. observe risks at low dose rates rather than extrapolating them from high dose rates. (eg as
in the LSS study of Japanese bomb survivors)
d. found that risks do not depend on dose rate thus contradicting the ICRP’s use of a Dose
and Dose Rate Effectiveness Factor (DDREF) (which acts to reduce by half its published
radiation risks).
e. found radiogenic leukemia risks decline linearly with dose, contradicting earlier studies
suggesting a lower, linear-quadratic relationship for leukemia.
f. strengthen the Linear No-Threshold (LNT) model of radiogenic risks, as it now applies to
leukemias as well as to solid cancers.
g. found no evidence of a threshold below which no effects are seen, and
h. found a trend of increasing risk of solid cancer by attained age.
Because the INWORK findings are far-reaching in their implications, it is necessary to doublecheck their findings. This was carried out by recent exhaustive review (Hauptmann et al, 2020) of the INWORKS studies which examined possible sources of bias82 and confounding83. It concluded
that these epidemiological studies directly support the conclusion of increased cancer risks from
low doses of ionising radiation, with little evidence of bias and confounding. This is similar to the
findings of yet another study84 which also reviewed the INWORKS studies using specialist
statistical and epidemiological methods to look for evidence of bias. It found none.
References are available in the original CELA submission:
Concerned Citizens of Renfrew County and Area 