The U.S. Supreme Court has slashed the punitive damages awarded in the Exxon Valdez oil spill disaster from $2.5 billion to $500 million. The 1989 tanker accident fouled Alaska's Prince William Sound with 11 million gallons of crude oil, causing the collapse of the local marine ecosystem and leading to the bankruptcy of the native Chugach people.

Today's high court decision marks a win for Texas-based Exxon, which was originally ordered by a jury to pay $5 billion in punitive damages. During the time the matter has been making its way through the courts, more than 3,000 of the original plaintiffs died.

Greenpeace USA Executive Director John Passacantando criticized the ruling as a "mockery of justice":

"The worst environmental calamity in U.S. history will continue to haunt the Prince William Sound and those dependent upon it for their livelihoods. Crude oil still can be found under rocks along the Sound's shores, and fishery scientists estimate that only ten percent of the oil was ever cleaned up.

"As long as America maintains its addiction to oil, the country will remain at risk of environmental disasters such as the one caused by the Exxon Valdez."

In a statement released after the ruling, Exxon said it deeply regretted the incident and noted that it's paid $3.4 billion as a result -- an amount that covers compensation, cleanup, settlements and fines. Last year the company recorded a profit of more than $40 billion.

The court's decision comes as President Bush and Republican presidential candidate John McCain are pushing to lift the federal moratorium on offshore oil drilling, which would increase the likelihood of coastal spills.

(Photo of birds killed by Exxon Valdez spill from the online photo gallery of the Exxon Valdez Oil Spill Trustee Council)