Halliburton, the US energy services giant, has admitted destroying evidence relating to the 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico, the worst such disaster in American history.
A Justice Department statement released late Thursday said the company had agreed to plead guilty to criminal conduct that occurred when it was carrying out its own post-accident investigation.
Eleven people died and 4.9 million barrels of oil gushed into the Gulf over a three-month period after the explosion, with BP -- who leased Deepwater Horizon -- ending up paying billions of dollars in compensation and cleanup costs.
Halliburton Energy Services, BP's contractor, had been accused by the British oil giant of destroying evidence. BP has also asked Halliburton to pay damages stemming from the April 2010 accident off the coast of Louisiana.
The Justice Department statement said Halliburton -- which constructed the cement casing of the well at the center of the disaster -- had carried out its own internal investigations in May and June the same year.
However, the results of computer simulations conducted as part of that probe were ordered to be destroyed and were never recovered, it said.
In addition to a guilty plea -- which is subject to court approval -- Halliburton has agreed to pay the maximum statutory fine of $200,000. The company said in a statement that it would make a separate and voluntary $55 million payment to the National Fish and Wildlife Foundation.
The disaster wreaked havoc on the Gulf region's environment and economy.
The central subject of the cooperation and guilty plea deal was the number of heavy metal collars, known as centralizers, placed at various points on the cement casing of the Macondo well that eventually exploded.
The Justice Department said that prior to the blowout, Halliburton had recommended that 21 centralizers be used, but BP instead opted for six.
Halliburton's post-accident tests failed to back up its earlier suggestion.
"These simulations indicated that there was little difference between using six and 21 centralizers. (The) Program Manager was directed to, and did, destroy these results," the Justice Department statement said.
In a later incident in or around June 2010, similar evidence was also destroyed when Halliburton's cementing technology director asked another more experienced employee to repeat the simulations.
When he "reached the same conclusion" he was directed to "get rid of" the simulations, the statement said.
"In agreeing to plead guilty, Halliburton has accepted criminal responsibility for destroying the aforementioned evidence," the Justice Department added.
Halliburton's statement said the agreement with the Justice Department would conclude the criminal investigation into its actions over the giant spill.
"A Halliburton subsidiary has agreed to plead guilty to one misdemeanor violation associated with the deletion of records created after the Macondo well incident, to pay the statutory maximum fine of $200,000 and to accept a term of three years probation," it said.
Several government probes have castigated BP, rig operator Transocean and Halliburton for cutting corners and missing warning signs that could have prevented the disaster.
Last year, BP agreed to pay $4.5 billion in penalties and pleaded guilty to multiple criminal charges relating to the explosion and ensuing spill.
The company also spent more than $14 billion on the response and cleanup and has paid another $10 billion to businesses, individuals and local governments that did not join an ongoing class action lawsuit.