Building materials are a key component in local procurement. ICLEIs study of European cities found that spending on building construction and renovation was by far the biggest product groupconstituting from 15 to over 35 percent of procurement costs. Municipal purchasing has been a key factor in increasing energy efficiency, reducing sick building syndrome, supporting markets for certified wood, and eroding markets for PVC and other destructive materials. Procurement in green building is, however, a real challenge for municipalities because of the complexity of the product group and building process. In most cities building is the responsibility of a separate department over which the Central Purchasing office has little control. In some places, sustainable building sub-departments have developed within the building departments, and these have been useful in maintaining relationships with both city environment, energy and purchasing offices. In the mid-90s, Toronto was spurred primarily by concerns about waste to develop a GIPPER Guide to Green Procurement. GIPPER stood for Toronto's Governments Incorporating Procurement Policies to Eliminate Refuse, and its governing committee included representatives from Toronto area municipalities, Ontario Hydro, the Canadian Standards Assn., the provincial and the federal government. It included guidelines for the purchase of asphalt, brick masonry and tile; concrete; drywall and wood (City of Toronto, 1997). The potential of local green procurement has, however, barely been tapped. As suggested by ICLEI above, local procurement takes place in a realm that is conducive to grassroots citizen participation and education. It can complement strongly action geared to private green consumerism, and especially to community consumerism that, like government procurement, attempts to create alternative market power.