No single factor caused the Macondo well tragedy. Rather, a sequence of failures involving a number of different parties led to the explosion and fire which killed 11 people and caused widespread pollution in the Gulf of Mexico earlier this year. A report released by BP today concludes that decisions made by “multiple companies and work teams” contributed to the accident...Commenting on the report...BP’s outgoing chief executive Tony Hayward said: “The investigation report provides critical new information on the causes of this terrible accident. It is evident that a series of complex events, rather than a single mistake or failure, led to the tragedy. Multiple parties, including BP, Halliburton and Transocean, were involved..."