Kuwait, 1991: 520 million gallons. Iraqi forces emptied tankers to try to thwart a U.S. Marine landing.

Mexico, 1980: 100 million gallons. An accident caused an oil well to explode and collapse. The well spilled 30,000 gallons a day into the ocean for a year.

Trinidad and Tobago, 1979: 90 million gallons. A Greek tanker collided with another ship in a storm.

Russia, 1994: 84 million gallons. A pipeline leaked for eight months before it was noticed and fixed.

Persian Gulf, 1983: 80 million gallons. A drilling platform collapsed into the sea after being hit by a tanker. It leaked oil for seven months.