Supertanker wrecks off French coast - Mar 16, 1978 - HISTORY.com

One of the world’s worst supertanker disasters takes places when the Amoco Cadiz wrecks off the coast of Portsall, France, on this day in 1978. Although the 68 million gallons of oil that spilled from the Cadiz has since been exceeded by other spills, this remains the largest shipwreck in history.

The Cadiz was 65 meters longer than the Titanic and capable of carrying more than 250,000 tons of crude oil. The huge supertanker was owned by Amoco, an American company, but was registered in Liberia and helmed by a mostly Italian crew. On March 23, the Cadiz was traveling from the Persian Gulf to Le Havre, France. While negotiating a relatively crowded area of shipping lanes, the boat came across gale conditions, suffered a steering failure and drifted toward the rocky coast.

After a failed attempt by a German tugboat to pull the ship from the coast, the Cadiz ran aground and broke in two pieces three miles off the coast of Portsall. Due to the isolated location, poor weather and lack of a thorough emergency plan, officials were unable to recover any of the oil from the ship and it appeared that the oil would slowly leak out and damage the coastline.

When water and wind conditions suggested that the oil would drift out to the ocean rather than toward the coastline, it was decided to use explosives to open the hull immediately, releasing the 1.6 million barrels of oil quickly. French navy helicopters dropped 16 water bombs into the Cadiz. Unfortunately, the plan was not a complete success–much of the 68 million gallons of oil drifted to the coast.

Ultimately, 240 miles of France’s Brittany coast suffered oil damage. Although it later became a more commonplace feature of television news, this was the first time that images of oil-coated sea birds were seen by the world. In all, millions of dead mollusks and sea urchins washed ashore because of the spill. In addition, 20,000 birds and 9,000 tons of oysters perished. There were also reports of fish with tumors, likely caused by the oil, caught in the months following the spill.

The best estimate is that over $250 million in damages were incurred to the fishing and tourism industries in the area of the oil spill. Today, the Cadiz remains sunk in the sea bed. The wreck is largely covered by sea weed. As some of the water bombs used to empty the ship of oil failed to detonate and remain near the ship, diving near or exploring the wreck is prohibited.