large for building materials. For a building as a whole, the amount of embodied energy can equal the amount of energy it takes to run the building for anywhere from seven to twenty years, even in our harsh Canadian climate (Trusty & Meil, 1999). Pollution includes all the emissions of the mines and factories used to produce the material, as well as the emissions of useformaldehyde outgassing, and emissions from products used to clean and maintain the materialalong with the pollution resulting from its final incineration or landfilling. Performance refers to how well the material does its intended job. Materials with low durability, no matter how benignly produced, can hardly qualify as green. For materials like insulation and windows, performance goes beyond durability, since good thermal performance, for example, can actively save resources and energy. These three categories certainly overlap, as for example the performance of a window or roofing material may influence the resources and energy they use. To really appreciate how these criteriaalong with the general priorities for dematerialization and detoxificationapply to building materials, it is important to understand the distinctiveness of materials in construction. Perhaps the most important thing about building materials is that, because they are much longer-lived than most materials, they have a use-dominated life cycle. This tends to make durability and performance somewhat more important than for many other kinds of products. The following listadapted from Nadev Malin (1999), one of the USs main experts on building materialsconstitutes a very rough prioritization of evaluation for building materials. Note that the use phase comes first because of its importance, followed by manufacturing, extraction and disposal: