The U.S. Coast Guard said on Wednesday five times as much oil as previously estimated was leaking from a well beneath the site of a deadly drilling rig explosion as the slick threatened wide-scale coastal damage for four U.S. Gulf Coast states.

The Coast Guard said that London-based BP Plc — the owner of the well who is financially responsible for the cleanup — found a third leak in a well 5,000 feet under the sea off Louisiana’s coast.

“BP has just briefed me of a new location of an additional breach in the riser of the deep underwater well,” Coast Guard Rear Admiral Mary Landry, who is heading the federal cleanup effort, told reporters at a briefing.

Eleven workers are missing and presumed dead after the worst oil rig disaster in almost a decade.