Just to be clear, once fully charged I keep all of my power tool batteries C/W their chargers together in a cardboard box in the garage (which isn't attached to the house).
I "stay around" when these batteries are being charged and promptly unplug and seperate them when done. The only alternative location for them would be a garden box where I store flammable stuff (paint, adhesives, thinners etc), clearly this could be worse.
My question is: do these batteries explode only when they are being charged or when they are left fully charged?