The U.S. Coast Guard (USCG) summarizes reported oil spill data in its Pollution Incidents In and Around U.S. Waters, A Spill Release Compendium: 1969–2001. USCG aggregates the source data into five categories: marine vessels, pipelines, facilities, other, and unknown. The Bureau of Transportation Statistics has reviewed USCG’s detailed source data and classified each transportation-related reported oil spill incident by transportation mode. The data presented here are preliminary, as research on the dataset is ongoing.