Exxon Mobil Corp has agreed to pay 75% of the $US508 million ($587 million) in punitive damages awarded by the US Supreme Court in June over the 1989 Exxon Valdez oil spill on the south coast of Alaska.

US media said last week that the oil titan will distribute about $US383 million ($443 million) before legal costs are deducted to nearly 33,000 commercial fisherman and others who sued Exxon.

The judgement amounts to $US11,606 ($13,535) each before legal costs are deducted. Payments will commence from early October.

The battle continues over another $US70 million ($82 million) as well as potential interest of $US488 million ($570 million) on the Supreme Court judgement. Exxon has argued the interest isn’t owed.

The Exxon Valdez spilled some 34,000 tonnes of crude oil into Prince William Sound in one of the most devastating environmental disasters to occur at sea. The clean-up alone was estimated to have cost Exxon $US2.5 billion ($3 billion).

A report released last year estimates there is still 85 tonnes of oil remaining at Prince William Sound, declining at the rate of about 4% a year.