Published: Mar 08, 2011 5:32 PM EST
Updated: Mar 08, 2011 2:32 PM EST

NEW ORLEANS- The company at the center of the Gulf oil spill wants access to a key piece of evidence in the federal investigation so it can do additional testing it says a government contractor has refused to do.

BP said in court papers filed Tuesday that further testing of the failed blowout preventer will help determine why it didn't work as intended during the April 20 oil rig explosion off the coast of Louisiana. A federal judge did not immediately rule.

BP's request follows the U.S. Chemical Safety Board's objection to the government's decision to halt testing of the blowout preventer last Friday.

The board said there may have been a fundamental safety design problem with the pods that controlled the massive device, and it asked that more testing be done to confirm that.

Among other things, BP wants U.S. District Judge Carl Barbier to make sure other parties cooperate with BP in carrying out the additional testing. It said it could be necessary for Cameron, the company that made the blowout preventer, and Transocean, which was responsible for maintaining it, to supply engineering drawings and specifications.

The joint investigation team that has been overseeing the testing since November at a NASA facility in New Orleans said Friday that it believed its contractor, Det Norske Veritas, had performed the tests necessary to determine why the blowout preventer did not function as intended. It said Tuesday that official testing would not resume, but that BP and other interested parties were free to ask the court to allow them to do their own testing.

Det Norske Veritas is expected to submit its findings by March 20.

Blowout preventers sit at the wellhead of exploratory wells and are supposed to lock in place to prevent a spill in case of an explosion. The 300-ton device that was used with BP's Macondo well was raised from the seafloor Sept. 4. It sat at the NASA facility for two months before testing began.

The U.S. Coast Guard-Bureau of Ocean Energy Management Regulation and Enforcement panel investigating what caused the rig explosion and oil spill has been granted an extension until July to file its final report on the disaster. It is expected to make a preliminary statement by mid-April.

(Copyright 2011 by The Associated Press. All Rights Reserved.)