The Deepwater Horizon oil platform caught fire and sank in the Gulf of Mexico in April 2010, spewing thousands of barrels of oil into the water and along the southern U.S. coast.
Ian MacDonald, an oceanographer at Florida State University, told the National Wildlife Federation that dives to the bottom of the Gulf of Mexico revealed oil stretching far from the site of the April oil disaster.
"You could see oil," he was quoted as saying. "You could see stringers of oil even 10 miles away (from the Macondo well head) on the bottom."
MacDonald said it wasn't verified whether the oil was from the Macondo well or from natural seepage. He said, however, that the characteristics of the deposits suggested they weren't normal.
"The oil 2 1/2 miles from the well head comes from the Macondo well," he maintained.
NWF said about 113 miles of coastline in Louisiana remain closed because oil is washing up on the southern coast of the United States.