An environmental health scientist and mediator was appointed for the first time as a special master to oversee cleanup of a hazardous waste site in California. The case analysis examines the creative assimilation of Integralive/mutual gains bargaining (mediation) into a distributive/zero-sum bargaining construct (litigation). The special master played multiple, overlapping, and conflicting roles as the case unfolded. The interfaces and tensions of these roles produced a hybrid style of dispute resolution, termed "mediation-negotiation" by the author.