With the second anniversary of the Fukushima disaster approaching, nuclear supporters around the world are promoting a set of disingenuous arguments. With a full-frontal assault on science and logic they contrive to blame the profound impacts of the disaster not on the nuclear industry but on nuclear critics and independent scientists.
The industry-funded Australian Uranium Association (AUA) sets out these arguments in its first media release for the year. The AUA objects to estimates of the long-term cancer death toll from the Fukushima disaster based on estimates of population-wide (collective) radiation exposure. These estimates include a "very preliminary order-of-magnitude guesstimate" of "around 1000" fatal cancers, another scientific study suggesting "~100s cases" of fatal cancers, and a Stanford University study (pdf) that estimates "an additional 130 (15-1100) cancer-related mortalities and 180 (24-1800) cancer-related morbidities incorporating uncertainties associated with the exposure-dose and dose-response models used in the study."
So, what’s wrong with using collective radiation exposure figures to estimate long-term cancer deaths? Before talking about the real limitations of that approach, let’s pause and admire the AUA’s explanation:
"This method is akin to saying that small rocks thrown at a lot of people will kill some of them because the combined weight of the small rocks is large enough to do so. … In other words, science confirms common sense: small additional radiation exposures for a lot of people will not kill some of them just because the combined radiation exposure is large."
The rock analogy doesn’t square with the overwhelming weight of scientific opinion, which holds that there is no threshold below which ionising radiation is without risk. For example:
• The 2005 report of the Committee on the Biological Effects of Ionising Radiation of the US National Academy of Sciences states that: "The Committee judges that the balance of evidence from epidemiologic, animal and mechanistic studies tend to favor a simple proportionate relationship at low doses between radiation dose and cancer risk."
• A study published in the Proceedings of the National Academy of Sciences in 2003 concluded that "the most reasonable assumption is that the cancer risks from low doses … decrease linearly with decreasing dose."
• And to give one other example (there are many), a 2010 report (pdf) by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) states that "the current balance of available evidence tends to favour a non-threshold response for the mutational component of radiation-associated cancer induction at low doses and low dose rates."
So the AUA’s analogy with throwing rocks is silly — yet it is being trotted out ad nauseum by nuclear advocates.
The US Health Physics Society uses the rock analogy and adds this gem of an explanation: "… if the most highly exposed person receives a trivial dose, then everyone’s dose will be trivial and we can’t expect anyone to get cancer." Thus the problem of low-level radiation exposure risk is redefined as a non-problem of "trivial" doses which are, by definition, harmless. It would be too kind to describe that as circular logic — it is asinine (and a reminder that scientists themselves are sometimes guilty of great crimes against science and logic).
While the weight of scientific opinion holds that there is no threshold below which radiation exposure is harmless, there is less scientific confidence about how to quantify the risks. Risk estimates for low-level radiation exposure are typically based on a linear extrapolation of better-understood risks from higher levels of exposure.
This "Linear No Threshold" model has some heavy-hitting scientific support. The above-mentioned study reported in the Proceedings of the National Academy of Sciences states: "Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses currently appears to be the most appropriate methodology." Likewise, the above-mentioned US National Academy of Sciences report states that "the risk of cancer proceeds in a linear fashion at lower doses without a threshold and … the smallest dose has the potential to cause a small increase in risk to humans."
Nonetheless, there is certainly uncertainty with the LNT model — the true risks could be higher or lower. And, as the AUA trumpets, UNSCEAR and the International Commission on Radiological Protection (ICRP) recommend against using collective dose figures and LNT risk estimates to estimate total deaths (even though UNSCEAR itself uses that approach to estimate up to 4000 long-term cancer deaths (pdf) among the people who received the highest radiation doses from Chernobyl).
The problem with the recommendation from UNSCEAR and the ICRP is that there is simply no other way to arrive at an estimate of the death toll from Fukushima (or from Chernobyl, routine emissions across the nuclear fuel cycle, or anything else). Public health (epidemiological) studies of varying quality will be carried out in Japan, but all face great obstacles. Cancers are common diseases and isolating the contribution of one factor becomes a futile exercise, like trying to find a needle in a hay-stack. Another difficulty is that most cancers are multi-causal. The upshot is that cancer incidence and mortality statistics are being pushed up and down by a myriad of factors at any point in time and it becomes impossible or near-impossible to isolate any one factor.
Given the severe limitations of public health studies, we’d best return to collective dose estimates and the LNT model. By all means we should acknowledge the uncertainties. As the report from the US National Academy of Sciences states, "combined analyses are compatible with a range of possibilities, from a reduction of risk at low doses to risks twice those upon which current radiation protection recommendations are based."
The National Academy of Sciences makes the important point that the true risks may be lower or higher than predicted by LNT — a point that needs emphasis and constant repetition because nuclear apologists routinely conflate uncertainty with zero risk.
The AUA states: "We need to know if people die as a result of the releases." But the AUA rejects the only method of arriving at an estimate of the death toll from Fukushima and fails to suggest any alternatives.
The AUA goes further with this attack: "Those who use collective dose estimates of a Fukushima death toll should bear in mind the negative emotional effect of their advocacy, especially now that the world’s premier radiation protection organisations have made clear the absence of a scientific basis for the estimates of the alarmists."
Uranium industry consultant (and self-described "pro-nuclear environmentalist") Ben Heard ratchets up the rhetoric: "Building outrage through tried and true techniques is a known, understood and practiced part of activism. It needs to be called out, named and denounced loudly, clearly and often. They are doing harm. It is, in a word, outrageous."
Rather than untangling that tortured logic, let’s finish with a few simple truths about Fukushima. The most authoritative and detailed report to date was carried out by the Nuclear Accident Independent Investigation Commission (NAIIC), which was established by an Act of the Japanese Parliament.
The NAIIC report lifts the lid on the widespread corruption and collusion that led to the Fukushima disaster, stating that the accident was "a profoundly man-made disaster that could and should have been foreseen and prevented" if not for "a multitude of errors and wilful negligence that left the Fukushima plant unprepared for the events of March 11". The accident was the result of "collusion between the government, the regulators and [plant operator]TEPCO".
The report is equally scathing about the response to the disaster. It notes that most of the 150,000 evacuees from the nuclear disaster are still dislocated and they "continue to face grave concerns, including the health effects of radiation exposure, displacement, the dissolution of families, disruption of their lives and lifestyles and the contamination of vast areas of the environment."
Regardless of the long-term death toll, the Fukushima disaster has caused immense suffering and it will be decades before we’ve heard the last of it. For uranium industry spivs to blame that suffering on "alarmists" using collective dose figures and LNT risk estimates is disingenuous. They ought instead to be asking themselves some hard questions about why they turned a blind eye to the endemic corruption and collusion in Japan’s "nuclear village" — corruption and collusion that was responsible for the Fukushima disaster and countless other accidents and "incidents". There was a mountain of evidence on the public record long before the Fukushima disaster.