Researchers told The Washington Post that oil and tar from the Exxon Valdez spill 21 years ago and the 1979 Pemex blowout in the gulf can still be found on the seafloor.
"It's still sitting there," Stan Rice, a program manager for the National Oceanographic and Atmospheric Administration in Alaska, told the Post. "It's still liquid; you can still smell it and touch it."
The Post said research into the long-term effects of crude spills has not been very extensive. There is also scant data on oil at depths like the current leak going on 5,000 feet below the gulf.
Of particular concern are marshlands because they are largely protected from waves and tides that tend to break down oil globs over time. And although the gulf will eventually recover, scientists said, it could take decades for the oil to disappear entirely.
Copyright 2010 United Press International, Inc. (UPI).