A U.S. presidential commission report spreads the blame for the death of 11 workers in the explosion on the Deepwater Horizon drilling rig last April and the subsequent leak of more than 4 million barrels of oil into the sea.

A portion of the final report of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling was released this week. The full report is set for release next week.

U.S. President Barack Obama established the commission to find the underlying causes of the explosion on the Deepwater Horizon rig on the Gulf of Mexico about 80 miles south of the Louisiana coast.

The explosion April 20 killed 11 workers and led the rig to sink two days later. The well on the gulf floor leaked tens of millions of gallons of oil before it was sealed Sept. 19.

In an interview with the BBC Thursday, Don Boesch, a member of the investigating commission, said, "There was a whole sequence of poor decisions with unfortunate consequences, when put together, we concluded that there was a lack of a systematic safety program by BP in conjunction with the other contractors, both the operator of the rig (Transocean) as well as the cementing company Halliburton."

Almost all of those decisions involved saving time, said Boesch, who is president of the University of Maryland Center for Environmental Science.

"For example, the lack of a proper test that was done and the cement that was used to seal the bottom of the well, that was pretty clearly the direct responsibility of Halliburton," Boesch said.

"When the well started to blow there were decisions made by Transocean about how the material coming up the well was handled, and those were unfortunate, fateful, decisions which actually led to the explosion," he said.

The presidential panel also cited the lack of safety measures in place prior to the accident.

"BP did not have adequate controls in place to ensure that key decisions in the months leading up to the blow-out were safe or sound from an engineering perspective," the report said.

The report is also critical of government regulators.

"What we found was very limited oversight of these various activities and decisions, that the agency responsible in the Department of the Interior was understaffed and didn't have the inspectors and technical analysts who were up to the task fully," Boesch said.

As for the future of deep-water drilling, Boesch said safe deep-water drilling cannot take place without a very strong safety culture within the industry … and what we found was that this safety culture was lacking."

"The future of this activity must rely heavily on the industry stepping up and putting those processes in place," Boesch said.

The commission, in its conclusion said, "The blowout was not the product of a series of aberrational decisions made by rogue industry or government officials that could not have been anticipated or expected to occur again."