For many reasons (which I will not attempt to discuss here) I think it is unproductive to try to use statistics to calculate one's risk of death from WMD.
However, I think it is illuminating to consider that the odds of having been killed by the al Qaeda attacks on the WTC, etc. were approximately 1/94,000, a number quite similar to the hypothesized figure of 1/100,000+ odds of dying from a WMD attack. (Assumes 3000 deaths divided by US pop. of 282,000,000).
Just an observation,
John