Our next adventure with falling satellites could be a wicked one: a Russian Mars probe is stranded in orbit, and unless the problem is fixed it will fall to Earth within weeks. Perhaps there is the usual 1-in-3500 chance a piece of it will hit a human, but the bigger problem is that it contains 7 metric tons (15,400 lbs) of hydrazine and nitrogen tetroxide -- both highly toxic substances.
In fact, in 2008 the US shot down a spy satellite that contained hydrazine rather than let it fall back to Earth. And that one only contained about 1,000 lbs of hydrazine -- although some people thought the military exaggerated the threat just so they could protect its spy technology or just to get in some rare target practice.
Still, 15 times as much of the stuff has the possibility to cause some problems if it falls in the wrong place. With the 2008 satellite:
Joint Chiefs of Staff Vice Chairman Gen. James Cartwright cast the threat from the satellite in much less dire terms. Even if the hydrazine were released, he noted, the effects would likely be mild — akin to chlorine gas poisoning, which can cause burning in the lungs, and elsewhere. The area affected would be "roughly the size of two football fields [where you might] incur something that would make you go to the doctor."(Today I received a press release from someone about "Long Beach Moms Organize Stroller Brigade on the Boardwalk to Demand Protections from Toxic Chemicals," but I think that's just a coincidence.)
The site russianspaceweb.com says they will have updates on this latest situation, but if you see a satellite coming your way you should probably take cover.