History's Worst Oil Spills

On April 20, 2010, an explosion aboard the Deepwater Horizon, a large drilling rig leased by the oil company BP, killed 11 crew members and set off a massive blaze. The burning rig sank two days later into the Gulf of Mexico, unleashing a toxic gush of oil that began leaking from the stricken well at an alarming rate. Over the next three months, oil continued to seep into the Gulf and eventually began washing into ecologically sensitive coastal regions in Louisiana, Mississippi, Alabama and Florida. Meanwhile, a series of efforts to plug the spewing well–including the lowering of a containment dome and the use of robotic repair vehicles–failed to stem the flow. In mid-July, the leak appeared to stop after BP successfully installed a cap on the well. The company is now focusing on achieving a more permanent solution with the so-called “static kill” and “bottom kill” methods, which involve pumping mud and cement into the well.

Scientists have struggled with establishing precise figures for the oil flow rate and the total amount of crude that has spilled into the Gulf. On August 4, 2010, the U.S. Geological Survey and the National Oceanic and Atmospheric Administration released a report estimating that nearly 207 million gallons have leaked from the well. If that figure is correct, the Deepwater Horizon incident now stands as the second-worst oil spill in history, ranking just below the infamous Gulf War spill, which dumped 240 million gallons of oil into the Persian Gulf in 1991. The following list outlines the oil spills that, at least until now, were the largest in terms of quantity leaked.

1. Gulf War Oil Spill
Millions of gallons: 240
In January 1991, Iraqi forces deliberately released more than 240 million gallons of crude oil into the Persian Gulf in an attempt to thwart an amphibious landing by the U.S. Marines. The resulting oil slick ravaged the area’s marine ecosystem, killing thousands of seabirds and endangering other wildlife. To date, it remains the worst disaster of its kind.

2. Ixtoc I
Millions of gallons: 140
The exploratory oil well Ixtoc I exploded in the Gulf of Mexico on June 3, 1979, spewing 140 million gallons of oil into the open sea. It took control experts more than nine months to cap the spill and begin cleanup. Thousands of endangered sea turtles were airlifted to safety when the oil slick encroached upon their nesting site.

3. The Atlantic Empress and the Aegean Captain
Millions of gallons: 90
On July 19, 1979, two gigantic supertankers collided off the Caribbean island of Little Tobago during a tropical rainstorm. The accident killed 26 crew members and dumped millions of gallons of crude oil into the sea.

4. Fergana Valley
Millions of gallons: 88
In March 1992, 88 million gallons of oil spilled from a well in Fergana Valley, a densely populated industrial and agricultural zone in Uzbekistan. The incident remains the largest inland oil spill in history.

5. Nowruz Oil Field
Millions of gallons: 80
On February 10, 1983, at the height of the Iran-Iraq War, an oil tanker collided with the Nowruz platform in the Persian Gulf. The slick caught fire when Iraqi planes attacked, and it took Iranian workers more than six months to cap the well. Eleven people died in the process.

6. ABT Summer
Millions of gallons: 80
The Liberian supertanker ABT Summer exploded off the coast of Angola on May 28, 1991, killing five crew members. Millions of gallons of oil leaked into the Atlantic Ocean.

7. Castillo de Bellver
Millions of gallons: 79
On August 6, 1983, a fire broke out aboard the Spanish tanker Castillo de Bellver, causing a massive explosion that spilled 79 million gallons of oil off the coast of Cape Town, South Africa. A shift in winds pushed the oil offshore, minimizing the disaster’s environmental effects.

8. Amoco Cadiz
Millions of gallons: 69
On March 16, 1978, the Amoco Cadiz supertanker wrecked off the coast of Portsall, France. Ultimately, 240 miles of France’s Brittany coast suffered oil damage, with millions of dead mollusks and sea urchins washing ashore. This was the first time images of oil-coated sea birds were seen by the world.

9. M/T Haven
Millions of gallons: 45
The M/T Haven, a Very Large Crude Carrier (VLCC), suffered a huge explosion off the coast of Genoa, Italy, on April 11, 1991. Six crew members were killed, and the Mediterranean coasts of Italy and France remained polluted for the next 12 years.

10. Odyssey
Millions of gallons: 42
In November 1988, the American-owned Odyssey drilling rig burst into flames and split in two off the coast of Novia Scotia. The accident resulted in one fatality.