The Clean Air Act Watch List and federal oversight of state enforcement efforts

Abstract

For major federal environmental statutes in the United States, primary monitoring and enforcement responsibilities rest with most states. The Environmental Protection Agency (EPA) is charged with overseeing state efforts and has at its disposal formal tools to discipline lax states, tools which are rarely used. In this paper, we explore the extent to which the EPA's now-defunct Clean Air Act Watch List served as an informal tool for influencing the enforcement activities of state regulators. We estimate event studies designed around the primary listing criteria for the Watch List. Our empirical results are consistent with the average state regulator acting to reduce the chances of their facilities appearing on the Watch List. We also examine heterogeneity in the response to the Watch List between two states with high numbers of regulated facilities, Texas and California. We find a larger change in enforcement activity under the Watch List among state and local regulators in Texas compared to California.