And well they SHOULD!  

You don't say this, but radiation damage does not fall off as expected with decreasing dosage--and certainly not linearly!    

This has been a medical surprise.  While standards for high level dosage were got in hand early, through the course of the 20th century low levels standards had to be revised upward several times.  

Low level radiation is MORE dangerous than it "ought" to be!  

Also, for many chemical poisons, there is a threshold below which you either recover without lingering effects, or don't take damage.  Below such a threshold you really are safe.  

Radiation is not like that.  You ALWAYS take damage, in the form of a chance of lethal cancer, illness, mutation or the like.  

In the proper sense of the word, there is NO safe dosage.

(Not even Earth background is safe, though at least it  IS several ORDERS of magnitude lower than the exposures you contemplate.)

And that is another thing about the nuke industry--the only valid comparison is with Earth background.  Above that, you are talking excess cancers, illness, &c.  And yes you can ask, well, how many, indeed that is what you should ask, because every single one above background is a death caused by deliberate human action.  

The Fates are kind.