FACTBOX-Gulf oil spill was among world's worst

(For story on spill anniversary, click [ID:nN14225897])

April 15 (Reuters) - April 20 marks the first anniversary of the Deepwater Horizon rig explosion in the Gulf of Mexico that spewed more than 4 million barrels of oil (168 million gallons/636 million liters) into the ocean in three months in the world’s worst ever accidental offshore oil accident.

Here are some other major oil spills and leakages:

1991 - During the Gulf War, Iraqi forces opened valves and destroyed oil facilities in Kuwait, releasing about 520 million gallons (1.9 billion litres) of oil, creating a slick that covered some 4,000 square miles (10,360 square km) in the biggest spill in history.

1989 - The Exxon Valdez ran aground on a reef in Alaska’s Prince William Sound, spilling 10.8 million gallons (40.8 million litres) of oil. It polluted more than 1,100 miles (1,609 km) of coastline and devastated wildlife in what was previously the largest spill in U.S. history.

1983 - In the gulf off Iran, a tanker struck a drilling platform which collapsed into the sea, releasing some 80 million gallons (303 million litres) before it was repaired.

1983 - The Castillo de Bellver sanks off the South African coast, spilling 79 million gallons (300 million litres) of oil.

1979 - A Greek oil tanker collided with another ship during a tropical storm, spilling 90 million gallons (340 million litres) of crude oil off the coast of Trinidad and Tobago.

1978 - The Ixtoc exploratory well blew out in the Bay of Campeche off Ciudad del Carmen, Mexico. By the time it was brought under control almost a year later, it spilled some 140 million gallons (530 million litres) of oil into the bay.

1978 - The Amoco Cadiz ran aground off the coast of Britanny, France, spilling its entire cargo of 69 million gallons (260 million litres) of oil and polluting 200 miles (322 km) of coastline.

1967 - The Torrey Canyon, one of the first oil supertankers, hit a reef and spilled 31 million gallons (117 million litres) of crude oil in the sea between England and France in the first major oil spill. It contaminated about 180 miles of coast (290 km), and many of the attempted measures to clean up the slick proved more deadly to wildlife than the oil. (Editing by Pascal Fletcher and Philip Barbara)