Until late 2001, the U.S. Coast Guard (USCG) summarized reported oil spill data in its Pollution Incidents In and Around U.S. Waters, A Spill Release Compendium: 1969-2001. USCG aggregated the source data into five categories: marine vessels, pipelines, facilities, other, and unknown. For the previous two editions of this report, the Bureau of Transportation Statistics (BTS) reviewed USCG's detailed source data and classified each transportation-related reported oil spill incident by transportation mode. In December 2001, USCG changed the database used to produce the spill compendium, and many of its tables were altered. The new database system, Marine Information for Safety and Law Enforcement (MISLE), is intended to collect data more efficiently. MISLE does not explicitly identify nonmarine spill sources, including aircraft, highway, rail, and pipeline. USCG is working on possible methods for extracting nonmarine-related sources but no tools are currently available. As a result of these issues, BTS was unable to update oil spills data for this report.