The Village would presumably be stuck with 100% of the remediation costs if it decided to obtain the property at a depressed price by formally declaring the area “blighted” and invoking its power of eminent domain. On the other hand, the Village could just make a free market offer with a lowball number that takes into account the anticipated costs of remediation. One wonders, however, if the current owners would be motivated to sell in that circumstance. More likely, they would take such an offer as an invitation to negotiate. In that event the Village would need to have a (closely guarded secret) topmost number in mind and be ready to threaten to walk, and then actually walk away from the deal, Trump-style, if (when) the current owners get too greedy.
