The Amoco Cadiz oil spill happened on March 16, 1978, when the oil tanker Amoco Cadiz, owned by the American company Amoco, hit rocks near Portsall Rocks, which are 2 kilometers (1.2 miles) from the coast of Brittany, France. The ship broke into three pieces and sank. According to the US National Oceanic and Atmospheric Administration (NOAA), the spill released 220,880 tonnes of oil, which is equal to about 58 million gallons or 256.2 million liters. This was the largest oil spill of its kind at that time.

Sequence of events

The oil tanker Amoco Cadiz, owned by the US-based petroleum company Amoco, was traveling from the Persian Gulf to Rotterdam, Netherlands, with a planned stop at Lyme Bay, United Kingdom. While passing through the English Channel, the ship faced strong winds and rough seas. At about 09:45, a large wave hit the ship's rudder, causing it to lose control. This was later found to be caused by broken parts in the steering system, which led to a loss of hydraulic fluid. Efforts to fix the damage and regain control failed. At 10:20, Amoco Cadiz reported that it could no longer move and requested help from other ships. A call for tugboat assistance was made at 11:20.

The German tug Pacific arrived at the scene at 12:20 but could not attach a tow line until 14:00 because of the rough sea. The tow line broke at 16:15. Multiple attempts were made to connect another tow line, and Amoco Cadiz dropped anchor to stop drifting. A successful tow line was attached at 20:55, but the ship continued drifting toward the coast because of its large size and strong winds.

At 21:04, Amoco Cadiz ran aground for the first time, causing its engines to flood. It ran aground again at 21:39, tearing open its hull and starting an oil spill. The crew was rescued by French Naval Aviation helicopters at midnight, and the captain and one officer stayed on the ship until 05:00 the next morning. On 17 March at 10:00, the vessel broke in two, spilling all 1.6 million barrels (250,000 m³) of oil. It broke again 11 days later due to heavy seas. The wreckage was later destroyed by the French Navy using depth charges.

Oil spill

The ship Amoco Cadiz carried 1,604,500 barrels (219,797 tons) of light crude oil from Ras Tanura, Saudi Arabia, and Kharg Island, Iran. It also had nearly 4,000 tonnes of bunker oil. Severe weather caused the ship to break apart before any oil could be removed. This led to the entire cargo of crude oil (owned by Shell) and 4,000 tons of fuel oil spilling into the ocean.

A 19 km (12 mi) long oil slick and heavy oil pools spread over 72 km (45 mi) of the French shoreline due to northwesterly winds. Over the next month, prevailing westerly winds carried the oil about 160 km (100 mi) east along the coast. One week after the accident, oil reached Côtes d'Armor. Oil seeped into beach sand up to 500 millimetres (20 inches) deep. Under the sand, oil formed two or three layers because of sand movement during rough weather. Piers and slips in small harbors from Porspoder to Brehat Island were covered in oil. Other affected areas included the pink granite rock beaches of Trégastel and Perros-Guirec, as well as tourist beaches at Plougasnou. One month after the spill, oil covered about 320 kilometers (200 miles) of coastline. Beaches in 76 Breton communities were affected. On rocky shores with strong wave action, oil disappeared quickly. However, in sheltered areas, oil formed a thick, sticky layer called an asphalt crust that remained for years.

The shipwreck’s remote location and rough seas delayed cleanup efforts for two weeks. According to the "Polmar Plan," the French Navy handled offshore cleanup, while the Civil Safety Service managed shore cleanup. Although 100,000 tons of oil and water were collected, less than 20,000 tons of oil were recovered after refining.

The type of oil and rough seas caused a thick, sticky mix of oil and water called "chocolate mousse," which made cleanup harder. French authorities avoided using dispersants in sensitive areas and nearshore waters shallower than 50 meters (160 feet). If dispersants had been used from the air near the spill, the mousse might not have formed.

The Amoco Cadiz spill caused the largest loss of marine life ever recorded from an oil spill. Most animal deaths occurred within two months of the spill. Two weeks after the accident, millions of dead mollusks, sea urchins, and other sea creatures washed ashore. Nearly 20,000 dead birds were found, with diving birds making up most of them. Oyster deaths were estimated at 9,000 tons. Fishermen reported catching fish with skin sores and tumors, and some fish had a strong petroleum taste. While populations of echinoderms and small crustaceans nearly vanished, many species recovered within a year. Cleanup activities, such as pressure-washing rocky shores, also harmed habitats.

The Amoco Cadiz spill, the largest at the time, was studied extensively, with research continuing into the early 21st century. It was the first spill to oil estuarine tidal rivers. No follow-up plans existed to address asphalt formation or long-term problems after cleanup.

Beaches in some areas eroded further because gravel removed to lower the beach height was not replaced. Many affected marshes, mudflats, and sandy beaches were low-energy areas. Oiled sediment remains visible in some sheltered regions. Layers of oil still lie buried in impacted beaches.

Culture

The oil spill from the Amoco Cadiz is mentioned in a song by Steve Forbert about oil pollution. The musician Speedy J has a song titled "Amoco Cadiz" on his album A Shocking Hobby. A French pop singer named Alain Barriere released a popular song called "Amoco" in France.

A movie called Days of Fury (1979), directed by Fred Warshofsky and hosted by Vincent Price, includes footage of the Amoco Cadiz incident.

Legal claims

In 1978, it was estimated to have caused $250 million in damage to fisheries and tourist attractions. The French government filed claims totaling 1.9 billion French francs with U.S. courts. Using the 1978 exchange rate and adding interest, the total reached at least $1.6 billion. In 1984, after 3½ years of legal proceedings, U.S. District Court Judge Frank J. McGarr ruled that Amoco was responsible for the damages. The judge also stated that Amoco had delayed necessary maintenance on the vessel to keep it operating at sea. In 1992, Amoco chose not to appeal the court's decision.