Investigators working to piece together the data that workers on the Deepwater Horizon saw in the rig’s final hours have run into a roadblock, according to a letter sent Monday to the presidential panel’s commissioners.

A company called National Oilwell Varco, an offshore drilling company, provided the data displays aboard the rig and is standing in the way of the investigators’ effort to reconstruct data displays similar to the ones on the rig using data supplied by BP, the investigators said:

For over a month, we have attempted to elicit NOV’s assistance on this matter. They have been generally uncooperative, either in the form of refusal or delay.

“The men who know the precise answers to those questions … are deceased,” wrote investigator Fred Bartlit. “All we have is the data. We request your assistance in obtaining NOV’s cooperation.”

National Oilwell Varco, in a statement, said it rejected the investigators’ requests out of concern that trying to recreate the displays could produce a “misleading picture of what actually happened.”

Read the investigators' letter.

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