WASHINGTON – Energy services firm Halliburton 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 (IW 1000/4) -- which 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.

Computer Simulations Destroyed

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.