A Halliburton official testified he was aware of some irregularities in the cement from the Macondo well after the 2010 BP oil spill in the Gulf of Mexico.
Timothy Probert, who headed Halliburton's safety program, told a civil court determining liability for the disaster that there were irregularities in the company's testing of the cement slurry after the blowout but did not specify what those irregularities were, The (New Orleans) Times-Picayune reported Monday.
Probert said he was "not involved in any way with any subsequent investigation" of the cement mixture.
BP last year alleged Halliburton destroyed test results regarding cement used to seal the well beneath the Deepwater Horizon rig.
A report by U.S. regulars determined that a faulty cement barrier was partly responsible for the blowout that led to the explosion that sunk the rig.
Eleven rig workers died in the blast that led to the worst offshore oil spill in U.S. history.