So as an EV battery degrades over time, the driver and passengers are exposed to a toxic vapor cloud?
“the driver and passengers are exposed to a toxic vapor cloud?”
I’m pretty sure these cells do not out-gas during normal operation the way lead-acid automotive batteries used to do. I grew up in an era of lead-acid auto batteries and I was taught in the 60s to NEVER make ground contact on the battery terminal because of the risk of a hydrogen explosion. I never actually heard of a battery exploding due to hydrogen off-gassing, but was warned about it. You always attached the red jumper cable to the positive battery terminal, then the black jumper cable to the car chassis away from the battery. That kept the sparks away from the battery.
If the battery sends out a Vapor Cloud, it happens fast and big. You’ll know it’s time to abandon ship if you see that happening.