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Radiating Complacency

The International Commision on Radiological Protection (ICRP) is a panel of experts born out of a gathering of radiologists in 1928 at Stockholm. Supposedly watchdog of public health, they have over the years zealously guarded the interest of the ‘experts’ (nuclear industry in particular). Below we reprint 3 articles from two magazines which have in the past taken a generally pro-nuclear stand. The limits set for exposure to radiation are far too lax.

The experts on radiation have got it hazardously wrong. ICRP used to believe that there
was a safe level of radiation exposure. Then, in the 1960s, it admitted that the risks of radiation
simply increase with the dose received; there is no level of exposure below which radiation
is completely safe and above which it becomes nasty. The commission said then that the change in risk should be treated as smooth, even for small doses. It probably shouldn’t be. Some new evidence suggests that risk may even rise faster at low levels of radiation than at higher ones.

For practical purposes a safety line has to be drawn. The ICRP, which is meeting at Rome in Italy, is suppased to chalk in that demarcation line. The present line is drawn at 50 milli Sieverts (mSv) a year for those subjected to radiation at work; for members of the public it is five mSv a year, with a recommendation that their average over a lifetime should not exceed one mSv a year. So a worker getting the full 50 mSv a year will in 1½ years suffer the full dose an ordinary person is supposed to be permitted in his lifetime And the permitted limits themselves suddenly look too high for the public, and far too high for the workplace.

The commission is concerned mainly with two things. One is a measure of the link between
radiation dose and cancer risk; the other is a criterion of acceptable risk. The “safe limit”
is the dose that carries the highest acceptable risk of cancer, The latest ICRP risk estimate
(set in 1977) states that if im people each receive a dose of 50 mSv over a year, 625 of them Will eventually die from radiation-induced cancer. So a person who has a year’s worth of radiation
at the workplace limit faces a risk of death of one in 1,600. Over a working life of just under
40 years, those annual risks add up to a chance of death by radiation-induced cancer of around
two in too.

Many people now think the risks are much greater. In 1980 a joint sub-committe of
America’s National Academy of Sciences and the National Institutes of Health gave a
higher risk estimate: between 790 and 2,500 deaths per im per 50 mSv per year. Recent
studies of the survivors of the Little Boy and Fat Man atomic-bomb attacks on Japan also
suggest that the relation between dose and cancer has been underestimated. More than 800 scientists and doctors have sent the ICRP a petition calling for an immediate reduction of present permitted limits by four-fifths.

It is not surprising that experts differ. They always do. The flaw in the present system is that
the particular group of experts that set the international guideline has persistently shown
a bias towards complacency. The ICRP played no part in the campaign to stop the tests of nuclear weapons in the atmosphere—tests which, according to some estimates, could by the end of this century have caused up to 3m people to die prematurely. It withdrew its support
from the rule which limited x-rays of women to ten days after the start of their periods in
order to avoid irradiating a very young embryo. Although nobody is sure that x-irradiation at
Such an early stage is harmful, the damage done by x-rays later in pregnancy is proven. The
commission is open to the charge that it puts the convenience of radiologists above all.

To deserve public confidence, the ICRP needs either to cut the present limits on exposure
to radiation 6r provide a convicing answer to its critics. Widening its membership to include
representatives of the public and workers who are exposed to radiation would help.

Source : The Economist (12. 9. ’87)


Vol 1. Issue 3