The U.S. Environmental Protection Agency (EPA) has prescribed the use of institutional controls at a significant number of sites that are being cleaned up under the federal Superfund program. Institutional controls include both legal and administrative mechanisms designed to limit exposure of humans and the environment to residual hazardous substances. They are intended to ensure that the actual use to which a site is put after remediation is compatible with the level of cleanup at the site and to limit exposure pathways to toxins of concern. Despite the increasing use of institutional controls at Superfund sites, there has been little analysis to date of the effectiveness of these controls in practice. This report investigates the effectiveness of institutional controls at four NPL sites. The Environmental Law Institute researched and analyzed the administrative, legal, economic, public health, and policy implications of using institutional controls to prevent exposure to residual hazardous substances.