What burdens should have to borne by residents of a jurisdiction adversely impacted by a project or policy that generally benefits residents elsewhere? The premise that citizens and officials of impacted communities should have available the necessary tools to mitigate adverse impacts, should they choose to do so, is contradicted by the observation that local capacity problems in effectively utilizing available impact mitigation options are compounded by the introduction of environmental risk considerations associated with low probability, high consequence occurrences. Analyzing four possible decision scenarios under conditions of uncertainty, the question of who would bear the cost of each kind of decision error was found to be at the root of the repository siting problem. Given "there is no risk-free environment," national policy must allocate risk by choosing between acceptance for society the Type I error and rejecting siting everywhere, or proceeding with siting somewhere and imposing exposure to the Type II error upon the impacted community. The latter choice would present two mitigation issues. One, under what conditions should a community accept exposure failure to predict a catastrophic impact outcome? Two, what institutional designs can more effectively link exposure to consequences of a low probability, high consequence occurrence with reduced probability of such an occurrence?