If they hit living beings BEFORE they strike the ground, then they'll be mixed with blood, but it'll probably be roasted blood.
Then there's those poor souls on the International Space Station, as well as those in aircraft.
What speed is Comet Ison moving at?
She is wrong about a lot of what she says, but there are indeed unknowns to consider (e.g. breakup, course deviation, amount of debris left in path of earth, and etc.) Where she really is wrong is her thinking the comet will pull meteorites out of their orbits and etc. ISON doesn't have anywhere near the mass for that. What we might see between now and the time earth passes through the trail left by ISON, is one heck of a light show and possibly numerous meteors in our sky. Their is even a slight chance, depending upon a breakup, that earth could be in the path of some of the debris - but miniscule.
There is also a chance of major CMEs from impacts of debris or comet with the sun.
That's a confirmed observation of other comets hitting the sun, much smaller than ISON: http://www.youtube.com/results?search_query=comet+CME&oq=comet+CME&gs_l=youtube.3..0.212.2865.0.3399.9.8.0.1.1.0.136.683.7j1.8.0...0.0...1ac.1.11.youtube.JeaZBUCXUNw