The development was not entirely unexpected. Lawyers representing businesses and others that suffered from the spill had long accused the company of conducting undocumented cement tests and then hiding the results. BP, the operator of the drilling site, had also accused Halliburton of destroying evidence of cement testing.
Edward Sherman, a Tulane University law professor, said the plea could suggest weakness in Halliburton’s position in negotiating a settlement over spill-related liabilities.
“Their willingness to plead to this may also indicate that they’d like to settle up with the federal government on the civil penalties,” he said. “It may indicate a softening of their position.”
Halliburton confirmed in a statement that it pleaded guilty to the misdemeanor charge and confirmed the plea agreement’s terms.
The disaster caused 11 deaths and triggered the largest U.S. offshore oil spill following the rupture of the Macondo oil well, which was 65 percent owned by BP, the British oil giant.
Halliburton had earlier provided cementing services to help seal the well.
According to the government, Halliburton recommended to BP that the Macondo well contain 21 centralizers, metal collars that can improve cementing, but BP chose to use six.
The government said that, during an internal probe into the cementing after the blowout, Halliburton ordered workers to destroy computer simulations that showed little difference between using six and 21 centralizers.
Efforts to locate the simulations forensically were unsuccessful, the government said.
A document detailing the allegations was filed with the U.S. District Court in New Orleans.
BP and Transocean Ltd., which owned the drilling rig, previously entered guilty pleas over other aspects of the Gulf oil spill, and agreed to pay respective criminal fines of $1.26 billion and $400 million.
Both declined to comment on the Halliburton plea.
Halliburton, BP and Transocean are also defendants in a federal civil trial that began in February to apportion blame and set damages for the oil spill.
During the trial, Thomas Roth, a senior Halliburton executive who was in charge of cementing operations at the time of the spill, acknowledged that because of the well design and other factors, “the cement placement was going to be a job that would have a low probability of success.”
Timothy Quirk, a Halliburton laboratory manager, testified that he conducted stability tests on cement samples from a similar blend that had been used in the well after the accident. Under instructions from a colleague, he said he did not prepare a laboratory worksheet. “It was unusual,” he conceded. He also acknowledged that he had thrown out his notes. Later tests showed that the cement was not stable.
The trial is scheduled to resume in September. Halliburton said in April it was in talks to settle private claims against it in the damages trial.