Halliburton and BP knew weeks before the fatal explosion of the Macondo well in the Gulf of Mexico that the cement mixture they planned to use to seal the bottom of the well was unstable but still went ahead with the job, the presidential commission investigating the accident said on Thursday.
In the first official finding of responsibility for the blowout, which killed 11 workers and led to the largest offshore oil spill in American history, the commission staff determined that Halliburton had conducted three laboratory tests that indicated that the cement mixture did not meet industry standards.
The result of at least one of those tests was given on March 8 to BP, which failed to act upon it, the panel’s lead investigator, Fred H. Bartlit Jr., said in a letter delivered to the commissioners on Thursday.
Another Halliburton cement test, carried out about a week before the blowout of the well on April 20, also found the mixture to be unstable, yet those findings were never sent to BP, Mr. Bartlit found.
Although Mr. Bartlit does not specifically identify the cement failure as the sole or even primary cause of the blowout, he makes clear in his letter that if the cement had done its job and kept the highly pressured oil and gas out of the well bore, there would not have been an accident.
“We have known for some time that the cement used to secure the production casing and isolate the hydrocarbon zone at the bottom of the Macondo well must have failed in some manner,” he said in his letter to the seven members of the presidential commission. “The cement should have prevented hydrocarbons from entering the well.”
The failure of the cement set off a complex and ultimately deadly cascade of events as oil and gas exploded upward from the 18,000-foot-deep well. The blowout preventer, which sits on the ocean floor atop the well and is supposed to contain a well bore blowout, also failed.