Never forget, a charged battery pack contains no less energy that a full tank of gas. We have 120 years of real world experience with the ICE vehicles and they are incredibly safe even though they carry 16-20 gal of gas. Responders know how to handle gas, you can see it, you can smell it, and everyone knows it is only dangerous if it has O2 and spark. Keep those two thing away and it is about no more dangerous than a strong alcoholic beverage.
A battery pack on the other hand is a black box containing unseen energy that can unexpectedly and suddenly do very bad things.