Ten years ago, on March 24, 1989, the tanker Exxon Valdez ran aground on a reef in Prince William Sound. In the days that followed, the ship spilled over eleven million gallons of Alaskan crude oil into the water. The oil coated shorelines along the sound, and killed hundreds of harbor seals and otters, and thousands of seabirds.

Workers launched an aggressive attack against the spill. Birds and animals were cleaned by hand. High-pressure hot water was used to blast the oily residue from the beaches, a move that in hindsight may also have done some damage. Exxon paid out billions in fines and compensation, and the tanker (later renamed the SeaRiver Mediterranean) was barred by federal law from ever entering Alaskan waters again. But is the story over?

After ten years, the trustees managing the cleanup efforts say that only two of the twenty eight species harmed by the spill, bald eagles and river otters, have fully recovered. Exxon claims that the trustees are using distorted definitions of the word "recovered," insisting that "the ecosystem in Prince William Sound is healthy, robust and thriving." Environmental groups counter that Exxon is trying to buy favorable science to support its position as a court considers awarding still more damages against the company.

It's a slippery situation - and we'll talk about it, on this hour of Science Friday.

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