Almost no 100-year stakeholders exist. Real property owners will have the most to lose but even they have a much shorter time horizon. The solution is probably for some combination of Federal and State led remediation funded by raising the local property taxes by an extreme amount (200-300%) matched by Federal funds. You have to inflict enough pain on the locals that the rest of the country won't complain when they are helped (see Detroit). Whether this is politically feasible (or even Constitutional) I don't know.