The Exxon Valdez ran aground on a reef in the Prince William Sound nearly 20 years ago. But the complex legal fallout from the ensuing environmental disaster and a record punitive damages award has just reached the shores of the U.S. Supreme Court.

Exxon Mobil Corp. recently filed a petition asking the high court to review and overturn a $2.5 billion punitive award — the largest punitive damages award ever affirmed by a federal appellate court, and larger than the total of all punitive damages awards affirmed by all federal appellate courts in history, according to Exxon’s counsel, Walter Dellinger, partner in the Washington, D.C., office of O’Melveny & Myers.