It cites a sequence of critical failures by its own staff, as well as rig operator Transocean and the cementing company. They include the following: The four-month investigation that undergirded the report was conducted by, BP's head of safety and operations, who headed a team of specialists. The report – which also offered 25 recommendations for improving deepwater oil drilling practices – was nevertheless hampered in arriving at any definitive conclusions in some areas because key evidence was not available to BP itself.