Over the past five decades, the federal government has enacted laws and developed regulations to manage actual and threatened hazardous releases. This paper describes a relatively understudied component of the nation’s response capability – the Superfund Emergency Response and Removal (ERR) Program. Drawing on a new dataset of 113 recent removal actions on 88 sites in the Mid-Atlantic region, we find a great deal of diversity across sites, from the discovery and cause of contamination to the types of risks and the cleanup strategy. The program addresses traditionally studied media such as soil, water, and air contamination, as well as risks from not-yet-released contained contaminants and potential fire or explosion. One of the program’s major strengths is its ability to address this wide range of threats, even though this very heterogeneity complicates research efforts to assess its net benefits. We describe the involvement of potentially responsible parties and EPA expenditures on removal actions. Finally, we consider future challenges for research into the net benefits of the program.