It's a serious problem in most US and Canadian cities. You've got all these quaint brick houses in the downtown core, on filled swamp, and they are death traps. What to do, what to do?
You could be like Seattle, and force the retrofits. Yet, they have found that even trying to put in sprinklers caused a massive abandonment of the older building stock. You could just raze everything, but that would look like downtown Toronto! The problem is worse in the States, where old building stock becomes the last refuge of the poor. As we saw with Katrina, they will be the first to suffer, and perhaps die.