[영문]Effective inter-organizational collaboration is essential to a communitys ability to leverage social and material resources for community problem solving, particularly in the face of complex public health problems. This study used network analysis to document the evolution of collaboration among 21 organizations in the Tar Creek Superfund site in northeastern Oklahoma from 1997 to 2005. The Tar Creek Superfund site was part of a major lead and zinc mining operation and suffers from widespread heavy metal contamination. An organizational network of 21 organizations and a subset of eight tribes were assessed through interviews at three points in time for density and centrality. In addition to collaboration on any topic, we examined information exchange and joint planning related to lead. Density scores were consistently higher in 2005 than in 1997 for both the full and tribal networks. Centralization indices for information exchange showed a marked reduction in the hierarchical structure of information exchange over time. Of particular note is that tribal linkages with local, state and federal agencies increased over time, as did inter-tribal linkages to address the lead issue.