Let's not downplay the hazard, either. It's not merely a little alcohol, and fighting a metal fire with reactive materials using water is not in anybody's best interest.
and
We're not talking about a small bit of alcohol burning. We're talking about explosive potential, sustained combustion, toxic combustion byproducts, and a sustainable ignition source that can easily propagate to other fuels, to say nothing of melting liquid metal.
SNS3Guppy:
I agree on your conclusion but not on the technicalities behind.
Technically it is mostly alcohol+ plastic burning.
The explosion comes from the metal containment allowing pressure to build which then escapes in an explosive manner once the can breaks. That's what causes the dynamics. It is a bit like blackpowder.
Ignite it openly and it will burn. Put it in a can and it will explode.
Again: It is not the relatively low amount of Lithium which causes the undeniable danger of these cells, it is the other combustibles inside....
Edit:
If you need a further hint towards the fact that the Lithium is not the most critical thing in these cells: The FAA considers water to be the best means for extinguishing burning Litium cells. You wouldn't really want to put out a reactive metal fire that way...