This project will investigate the empirical validity of the concern that the Potentially Responsible Parties (PRPs) influence both clean-up strategies that are chosen for Superfund sites and the pace of clean-up programs. The project will consist of two related components. In one part the researchers will model remedy selection as a bargaining process between public sector agencies responsible for clean-up and private firms responsible for payment. Drawing on the law and economics literature on out-of-court settlement of legal disputes, the researchers will create a structural model to predict sites at which PRPs will choose to settle. At the same time, they will examine the determinants of expenditure at the site using the status of PRP funding as an endogenous explanatory variable. The data will be analyzed by employing a joint model wherein the PRPs decision to fund clean-up and the level of clean-up expenditure at the site are simultaneously determined. The second component will focus on an examination of determinants of the pace of clean-up progress at Superfund sites. A specialized hazard of the duration of sites in each of the main stages of clean-up will be developed and estimated. This model will allow the researchers to examine the hypothesis that PRP-funding influences the rate of progress. It will also permit correction of the sample selection bias that could result from assuming that sites that have reached a given stage in the clean-up process represent a random sample of all National Priorities List sites.