k10 - do you really think the butyl and vinyl in your preferred product would create no, or even less, toxic fumes in a fire than rubberized asphaltic products like peel n seal? gimme a break - if fumes from a vehicle fire is a big concern better start stripping out all the wiring and upholstery, not to mention the paint
my preference for basic sound deadening and condensation prevention, from similar materials, and which is now being used in virtually all new building construction around here .... please make sure you don't wind up in a house or a vehicle fire

Bill