The investigation found a significant safety culture breakdown existed throughout BP's US refining network, with the company emphasising personal safety at the expense of process safety risks.
"Instances of a lack of operating disciplines, toleration of serious deviations from safe operating practices, and apparent complacency toward serious process safety risks existed at each of the US refineries"
Extract from independent safety panel report
"Instances of a lack of operating disciplines, toleration of serious deviations from safe operating practices, and apparent complacency toward serious process safety risks existed at each of the US refineries," the panel said.
The report said BP needs to strengthen management accountability and create a new system to identify and manage safety risks.
In addition, BP should engage an independent monitor to report annually to the board of directors on the implementation of the recommendations for five years, the panel said.
John Browne, BP's chief executive, called the investigation a "hard-hitting and critical analysis that focused on deficiencies and negatives".
However, he did not give a time frame for the implementation of the recommendations.
He noted that BP already had taken a number of steps since the explosion to improve safety, and it was important to compare the panel's suggestions with the company's own plans.
"The timing taken to get it right is appropriate," he said.
Browne, who is due to leave the company ahead of schedule next summer, defended the company's overall safety record, but said its oversight of the kind of safety measures that prevent huge mishaps "wasn't excellent enough".
He acknowledged the deficiencies in BP safety processes highlighted by the report. "BP gets it, and I get it too," he said.
The oil company has faced several problems at its US operations over the past two years including oil spills in Alaska and accusations of market manipulation.