I disagree with the radon LLE. There is lots of proof (Access to Energy, February 2002 list some)that moderate exposure to radon (such as that found in residential basements) will result in a negative LLE. The radon risk here is based on the linear no-threshold extrapolation of high radiation exposure data back to low levels. There is lots of proof that shows a mild benefit to low radon exposure, much the same way that low levels of sunlight help the body process vitamin E. It is theorized that low levels of radiation, like that from radon, forces the body to be on alert for mutated cells.
If you go to the web site, (actually a very good one) linked at the top of this article, Cohen addresses that in response to a letter commenting on this article. He explaned that he was using both 'official' government standards in compiling this list as opposed to reality. The linear 'no risk threashold' is still the government standard which causes large sums of money to be wasted that could be better spent on other serious health problems. Cohen himself published an article on the potential for a 'positive LLE' for low level radiation exposure.