Weeks before the Deepwater Horizon explosion, BP and subcontractor Halliburton were aware of tests results showing that the cement mixture designed to seal the well was unstable — but they used the mixture anyway, President Barack Obama's special commission investigating the environmental disaster said Thursday.
In the first official finding of responsibility for the April 20 blowout, which killed 11 and led to the biggest offshore oil spill in U.S. history, the commission determined that Halliburton had conducted three laboratory tests that indicated that the cement mixture did not meet industry standards. The cement secures the well pipes and keeps oil and gas from flowing up the well.
The result of at least one of those tests was given March 8 to BP, which failed to act on it, the panel's lead investigator, Fred H. Bartlit Jr., said in a letter delivered to the commissioners Thursday.
"There is no indication that Halliburton highlighted to BP the significance of the foam stability data or that BP personnel raised any questions about it," Bartlit said in his report.
Another Halliburton test, carried out about a week before the blowout of the well, also found the mixture to be unstable, meaning it was unlikely to set properly in the well, but those findings were never sent to BP, Bartlit found after reviewing previously undisclosed documents.
Although Bartlit did not specifically identify the cement failure as the sole or even primary cause of the blowout, he made clear in his letter that if the cement had done its job and kept the highly pressurized oil and gas out of the well bore, there would have been no accident.
The failure of the cement set off a complex and ultimately deadly cascade of events as oil and gas exploded from the 18,000-foot-deep well. The blowout preventer, which sits on the ocean floor atop a well and is supposed to contain a well bore breach, also failed.
In an internal investigation, BP identified the faulty cement job as one of the main factors contributing to the accident and blamed Halliburton, the cementing contractor on the Macondo well, as the responsible party. Halliburton has said repeatedly in public testimony that it tested and used a proper cement formula and that BP's flawed well design and poor operations caused the disaster.
In the letter, Bartlit said that his team recently asked Halliburton to turn over samples of the cement materials used at the well. The materials were tested by Chevron employees at a Houston lab. The employees were "unable to generate stable foam cement" from the materials, meaning the cement would not be strong enough to keep the well sealed.
Bartlit then asked Halliburton to turn over all of the tests it had run on the mixture.
Those documents showed that Halliburton had conducted four "stability tests" of the mixture. The first two were run in February using a slightly different recipe than the one eventually used at the well. Both of these tests indicated that the mix was unstable.
Halliburton sent results from only one of those tests to BP in an e-mail March 8.
Two more tests were conducted by Halliburton in April, using the actual recipe. The first test, conducted about seven days before the blowout, again showed the mix to be unstable, although Bartlit said it may have been improperly conducted. These results were reported internally at Halliburton, Bartlit said, "though it appears that Halliburton never provided the data to BP."
The report's release sent Halliburton shares plunging 16 percent to less than $30 in New York trading, but it recovered somewhat to close at $31.68, down $2.74 or 8 percent. BP's American shares, however, closed at $40.60, up 1.25 percent.
President Barack Obama appointed the commission to investigate the causes of the disaster and recommend new regulations to prevent a similar crisis. The commission is co-chaired by former U.S. Sen. Bob Graham, D-Fla., and William K. Reilly, who was administrator of the EPA under President George H.W. Bush.
Information from the New York Times and Los Angeles Times was used in this report.