If 100 mSv per year is safe, could a radiological weapon be harmless?

This is a good question to put out to the world before anyone has to seriously confront it for real, and I hope no one ever does. It would be interesting to know how the IAEA and various national nuclear regulators would answer it. Since the UN concluded its Chernobyl studies, and more so since the Fukushima catastrophe, these agencies that govern “nuclear safety” have been trying to get the world to calm down and accept the notion that people have nothing to fear from living in places that are up to 20 times above normal background levels of radiation.*

The public is told from time to time that another nuclear accident, dirty bomb terror attack, or nuclear bombing (accidental or intentional) could occur at some time in the future, and that it’s going to be important to stay calm and understand that we will be alright even in areas of elevated radiation. But here’s the problem. What are governments going to tell their people if a terrorist’s device spreads radioactive substances around a populated area? The attack will immediately be defined as an act of cowardly aggression that requires swift retribution, but if the device didn’t hurt anyone, and contamination levels are equal to or less than what the citizens of Fukushima City are being told to accept by global authorities on "nuclear safety," the attack would amount to no more than an annoying prank – by the standards of the United Nations. How could governments claim that they had been attacked by evil-doers when the contamination level was the same as what they excuse in a nuclear power plant accident?

*This may sound outrageous, but it is actually what is claimed by many "health physicists." The remarks quoted below come from the article Japan's Cut-Price Nuclear Cleanup:

“These workers may show a tiny increased risk of cancer over their lifetimes,” says Gerry Thomas, professor of molecular pathology at Imperial College, London University.

“100 millisieverts [about 20X above normal background radiation in Japan] is the dose we use as a cut-off to say we can see a significant effect on cancer rate in very large epidemiology studies. The numbers have to be large because the individual increase is minuscule. But, she added: “I would be far more worried about these workers smoking or feeling under stress due to the fear of what radiation might do to them. That is much more likely to have an effect on any one person's health.”

But Ian Fairlie, a London-based independent consultant on radioactivity in the environment is among those who have challenged the view of 100 mSv as a reliable threshold. Citing studies of tens of thousands of Japanese A-Bomb survivors, Fairlie concluded in a blog post last year that “very good evidence exists showing radiation effects well below 100 mSv”.

Justin McCurry and David McNeill. "Japan's Cut-Price Nuclear Cleanup." Truth-out.org. October 28, 2013.