British oil giant BP and its contractors failed to learn from earlier errors and showed an " insufficient consideration of risk" in the massive oil well blowout in the Gulf of Mexico, a group of U.S. scientists have concluded.

In a report released late Tuesday night, a panel of experts convened by the U.S. National Academy of Engineering said that " numerous technical and operational breakdowns" in the Deepwater Horizon oil rig explosion "suggest the lack of a suitable approach for managing the inherent risks, uncertainties, and dangers associated with deepwater drilling operations and a failure to learn from previous 'near misses.'"

"The events also suggest insufficient checks and balances for critical decisions impacting the schedule for 'abandoning' the exploratory well -- or sealing it in transition to production -- and for considering well safety," according to the report, which was commissioned by U.S. Secretary of the Interior Ken Salazar.

"Important decisions made to proceed toward well abandonment despite several indications of potential hazard suggest an insufficient consideration of risks," said Donald Winter, professor of engineering practice at the University of Michigan, and chair of the study committee.

"It's also important to note that these flawed decisions were not identified or corrected by BP and its service contractors, or by the oversight process employed by the U.S. Minerals Management Service and other regulatory agencies," he said.

The report cited numerous decisions that apparently contributed to the accident, beginning with continuing abandonment operations at the Macondo site despite several tests that indicated that the cement put in place after the installation of a long-string production casing was not an effective barrier to prevent gases from entering the well.

"The decision to accept the test results as satisfactory without review by adequately trained shore-based engineering or management personnel suggests a lack of discipline and clearly defined responsibilities," it said.

In addition, several clear failures in monitoring of the well appear to have contributed to its blowout, making ignition "most likely," the report said, adding that the failure of the blowout preventer and several questionable decisions made about the cement process are also factors in the blowout.

A final report is due in the summer of 2011.