This text, based on the SINTEF Offshore Blowout Database, thoroughlyexamines US Gulf of Mexico, Norwegian and UK North Sea blowouts that occurred from 1980 to 1994. It reveals the operations that were in progress at the onset of the blowouts, defines the causes for losing the primary and secondary barriers, and presents important parameters for preparing risk analysis, including flow path, release point, flow type, ignition time, duration, fatal-accident rate and pollution.