Regulating externalities is a major challenge when economic agents face uncertainty and disagreement. Traditional Pigouvian and Coasean approaches often struggle because they require either precise knowledge of externality costs or frictionless bargaining. We propose an "uncertainty-based regulation" (UBR) mechanism that leverages both uncertainty and firms' heterogeneous information to achieve socially efficient outcomes without requiring disclosure of private information. UBR adjusts firms' payoffs by adding a term that reflects how far their actions are from the average, with the size of the adjustment contingent on an observable outcome. This mechanism replicates the outcomes of a hypothetical market that internalizes externalities. We show that the equilibrium allocation induced by UBR is team efficient, dominates traditional regulatory tools, incentivizes information acquisition, and remains robust even when firms distrust each other's signals. Moreover, if brought to a vote, it would receive unanimous support, making it politically viable.