BP Plc will remove a failed blowout preventer from its ruptured Macondo well in the Gulf of Mexico under watchful eyes of investigators probing the deadly April 20 explosion, Reuters quoted the top U.S. official overseeing the oil spill response as saying. Retired Coast Guard Admiral Thad Allen told BP to submit a removal plan in a directive issued late on Friday and made public on Saturday after a 48-hour pressure test indicated the giant stack of pipes and valves could be removed and replaced with little likelihood of a leak. The plan must say how BP will contain a leak if necessary, Allen said. The blowout preventer is key evidence subpoenaed by federal investigators seeking the cause of the Deepwater Horizon explosion that killed 11 workers and unleashed the world's worst offshore oil spill. More than 4 million barrels of oil spewed into the Gulf, contaminating wetlands, fishing grounds and beaches from Louisiana to the Florida Panhandle. No oil has leaked since July 15, when BP sealed shut a provisional cap over the wellhead. Allen said BP's plan will ensure investigators with the U.S. Department of Justice and a joint team of the Coast Guard and the U.S. Bureau of Ocean Energy Management have "unfettered access to observe and record the entire removal and recovery process" and retrieve the equipment once it is brought ashore. That will include continuous live camera feeds of the removal by underwater robots with enough backups to ensure no interruptions, Allen said. In the interim, BP on Saturday said it was trying to fish out a drillpipe scientists believe is hanging inside the blowout preventer. BP said that process could take several days. Once another blowout preventer is installed on the well, BP said it will be able to resume drilling on a relief well to intersect the Macondo well to inject mud and cement and kill the leak for good. Allen said the intersect is expected sometime after the U.S. Labor Day holiday on Sept. 6.