Credit: Coast Guard.

I wrote about this issue back in May and June, and now the lead investigator of the presidential commission investigating the Deepwater Horizon oil spill in the Gulf has delivered to commissioners a letter that asserts that Halliburton staffers knew there were problems in the cement mixture used to line the drill bore. BP may not have know about this trouble.

From the New York Times:

In the first official finding of responsibility for the blowout, which killed 11 workers and led to the largest offshore oil spill in American history, the commission staff determined that Halliburton had conducted three laboratory tests that indicated that the cement mixture did not meet industry standards.

The result of at least one of those tests was given on March 8 to BP, which failed to act upon it, the panel’s lead investigator, Fred H. Bartlit Jr., said in a letter delivered to the commissioners on Thursday.

Another Halliburton cement test, carried out about a week before the blowout of the well on April 20, also found the mixture to be unstable, yet those findings were never sent to BP, Mr. Bartlit found.

As the Times notes, Bartlit stops short of placing the primary blame for the leak on the cement failure. The cement should have stopped the initial problems, but other equipment (remember the “blowout preventer”?) also subsequently failed.

A link to a PDF of Bartlit’s letter is in the Times story.

Stay tuned.