I don’t know if this is true, but I heard when lithium batteries burn they expel hydrogen cyanide gas which I would imagine does wonders for the environment, basically turning the car into a Nazi Auschwitz gas chamber killing everything around it.
A lithium-induced fire is particularly nasty, in that when elemental lithium comes in contact with water, it converts the water to lithium hydroxide and free hydrogen, which burns at one of the highest temperatures of any chemical oxidation, much hotter than a fire fueled by hydrocarbons.
Hydrogen cyanide, which is essentially hydrogen combining with the 78% of the atmosphere that is nitrogen, may form, but being extremely light in relation to the rest of the gases in the earth’s atmosphere, rises quickly and does not accumulate in any quantity near the ground.
I don’t know about hydrogen cyanide, but I do know they generate oxygen from the burning of the battery material. Hard to cut oxygen off when the car brought its own supply.
CC