New Orleans: Oil giant BP Plc says in an internal report that multiple companies and work teams contributed to the massive Gulf of Mexico spill that fouled waters and shorelines for months.

In a 193-page report posted on its website Wednesday, the British company describes the incident as an accident that arose from a complex and interlinked series of mechanical failures, human judgments, engineering design, operational implementation and team interfaces. The report was generated by a BP team led by Mark Bly, BP's head of safety and operations.

BP's report is far from the final word on possible causes of the explosion, as several divisions of the US government – including the Justice Department, Coast Guard and Bureau of Ocean Energy Management, Regulation and Enforcement – are also investigating.