"Monitoring by the oil spill response vessels escorting the tow confirmed that there were no signs of a discharge of oil during the transit, " the team said in a news release.
"BP must identify in the next 48 hours additional leak containment capacity that could be operationalised and expedited to avoid the continued discharge of oil, " wrote Rear Adm James Watson.
There was in fact a discharge from a drilling rig in March, but the oil people say it consisted of mud containing no substances that would affect the environment.