The blowout preventer is considered a key piece of evidence in determining what caused the explosion in April on the rig that unleashed the gushing oil.
Allen says the Department of Justice and other federal investigators are overseeing the work to remove the blowout preventer.
The goal is to drill the final 50 feet of a relief well beginning Sept. 7. The relief well has been called the ultimate solution to plugging the well.
Meanwhile, the U.S. is reopening more federal waters in the Gulf of Mexico for commercial and recreational fishing that had been closed because of the massive oil spill, a government official said Friday.
Oil sheen has not been seen there since July 29, and scientists found no oil or dispersants on samples of the area's shrimp and finfish.
Twenty percent of federal waters in the Gulf remain closed.
- At the hearings before the joint U.S. Coast Guard-Bureau of Energy Management, Regulation and Enforcement investigative panel, a BP drilling engineer who was a key decision maker at the rig that blew up refused to testify Friday. Mark Hafle exercised his constitutional right not to testify.
- The panel's goal is to determine what caused the explosion on the Deepwater Horizon rig that led to the largest offshore oil spill in U.S. history. The panel also will make recommendations to prevent such a catastrophe in the future.
The Associated Press contributed to this report.