(CNN) – A 1-by-5-mile sheen of crude oil mix has spread across the Gulf of Mexico's surface around the area where an oil rig exploded and sank, according to the Coast Guard.
"This is a rainbow sheen with a dark center," Coast Guard Rear Adm. Mary Landry told reporters.
Officials do not know whether oil or fuel are leaking from the sunken Deepwater Horizon rig and the well below, but BP Vice President David Rainey said "it certainly has the potential to be a major spill."
A remotely operated vehicle is surveying the area and cleanup efforts are under way, Landry said. The sheen "probably is residual from the fire and the activity that was going on on this rig before it sank below the surface," she said. Read more