You know what the problem with pulling something from Wikipedia is? It has citations. Specifically, for your pulled quote it cites this: http://www.phyast.pitt.edu/~blc/book/chapter13.html , and the section on "Plutonium Toxicity" about halfway down the page.

In particular, I commend to you the paragraphs starting with "In response, I offered to inhale publicly many times as much plutonium as he said was lethal." But more to my point:

"In summary, a pound of plutonium dispersed in a large city in the most effective way would cause an average of 19 deaths due to inhaling from the dust cloud during the first hour or so, with 7 additional deaths due to resuspension during the first year, and perhaps 1 more death over the remaining tens of thousands of years it remains in the top layers of soil. This gives and ultimate total of 27 eventual fatalities per pound of plutonium dispersed."

I can't quite get a direct cite, but I'm pretty sure the claim that a pound of plutonium dust can kill two million people is for a pound of plutonium dust being carefully doled out to two million people in precisely the quantities that will just barely kill them, because the previous paragraph is the description of what happens if you just sort of fling it at a city.

And an explosion from a rocket would actually be dispersed over a much larger area than merely a large city if it were going to hit anybody at all, because we don't launch anything immediately upwind of large cities. Think state-sized dispersal and you'd be closer.

"There have been fears expressed that we might contaminate the world with plutonium. However, a simple calculation show [26] that even if all the world's electric power were generated by plutonium-fueled reactors, and all of the plutonium ended up in the top layers of soil, it would not nearly double the radioactivity already there from natural sources, adding only a tiny fraction of 1% to the health hazard from that radioactivity."

"I have been closely associated professionally with questions of plutonium toxicity for several years, and the one thing that mystifies me is why the antinuclear movement has devoted so much energy to trying to convince the public that it is an important public health hazard. Those with scientific background among them must realize that it is a phony issue. There is nothing in the scientific literature to support their claims. There is nothing scientifically special about plutonium that would make it more toxic than many other radioactive elements. Its long half life makes it less dangerous rather than more dangerous, as is often implied; each radioactive atom can shoot off only one salvo of radiation, so, for example, if half of them do so within 25 years, as for a material with a 25-year half life, there is a thousand times more radiation per minute than emissions spread over 25,000 years, as in the case of plutonium.

"No other element has had its behavior so carefully studied, with innumerable animal and plant experiments, copious chemical research, careful observation of exposed humans, environmental monitoring of fallout from bomb tests, and so on. Lack of information can therefore hardly be an issue. I can only conclude that the campaign to frighten the public about plutonium toxicity must be political to the core. Considering the fact that plutonium toxicity is a strictly scientific question, this is a most reprehensible situation."

And thanks for leading me to the awesome link to post next time this comes up.