I would hate to think of all the chemicals giving off by a modern boats
burning interior before the fire even gets to the spray foam. I think
any fumes given off by the foam burning will be the least of your
worries - if you are not out of the boat by then, then you probably are
not escaping at all. The myth of foam burning seems to persist - the
company who sprayed my vessel used a fire rated/retardant material.