Eco-industrial development is still in its early stages, with many of the pioneering parks hardly representing ecological ideals. For example, the prototype Kalundborg park is anchored by a coal-fired power plant. But increasingly radical projects are emerging each year, with many combining industrial ecosystem organization with community development and the production of non-toxic benign materials. Here I will focus on a few of the models for eco-industrial park development that have special relevance for building materials: Materials Recovery Facility EIP: A Materials Recovery Facility (MRF) serves to match the wastes of a company or community with the resource needs of another. MRFs are a means of local economies beginning to mine the waste stream by turning waste into a resource. This kind of EIP can be focused primarily on building materials, or more generally on corporate or municipal waste. Construction and demolition (C&D) waste amounts to up to a third of municipal