A new type of environmental disaster happened 40 years ago today when oil supertanker Amoco Cadiz ran aground and began to break up three miles off the coast of Brittany, France.
Other ships carrying crude oil had run aground or sunk before, but never one of such immense size and capacity. At almost 335 metres long, the Amoco Cadiz was 65 metres longer than the Titanic and remains the biggest shipwreck in history.
Owned by American oil company Amoco, the supertanker was registered in Liberia and had a mostly Italian crew. On March 16th, 1978, she was heading through a southwesterly gale for Lyme Bay, on the Devon and Dorset coast. As she passed the western tip of Brittany she turned to avoid another ship and her rudder jammed full over to port.
The captain shut down her engines to make repairs, but they were not successful and she began to drift towards the Portsall Rocks, three miles off the Brittany Coast. A distress signal brought a tugboat to the scene which successfully attached a line to the Amoco Cadiz. For two hours it struggled against a strong wind and the supertanker’s sheer size to halt its drift, but then the towline snapped.
Switching the supertanker’s engines to full astern also helped slow its drift and the captain also dropped one anchor, but it broke in the strong swell. At just before 9pm a new towline was attached, but it was already too late and the Amoco Cadiz struck the first rocks soon after and began to leak oil from her hull. Her fate was sealed soon afterwards when another rock ripped a hole in her hull and flooded the engine room, leaving her without power.
The crew were safely evacuated but severe weather continued to pound the ship, now firmly aground, and it soon began to break up. The conditions also prevented any attempt to pump oil out of the wreck, meaning her entire cargo of almost 220,000 tons of crude oil would spill into the sea, together with 4,000 tons of fuel oil for her engines.
At first it was thought that, due to the wind and currents, the oil would drift out to the ocean and gradually disperse. Because of that it was decided to use explosives to further open the hull and release the oil, rather than have it seep out slowly over weeks and months. French Navy helicopters dropped 16 bombs into the stricken ship, although not all of them detonated.
Unfortunately, the plan was only a partial success and much of the 68 million gallons of oil formed into large slicks which began drifting towards the French coast. In total, 240 miles of coastline suffered damage and the military was drafted in to help with the extensive clean-up operation. Some of the first TV images of dead and barely alive seabirds coated in thick oil came after the Amoco Cadiz disaster.
It is thought about 20,000 birds died, along with millions of molluscs, oysters and sea urchins. In the months that followed, fishermen off the French coast also reported catching unusually high numbers of fish with tumours, most likely caused by ingesting oil particles. Most of the fish they caught were declared unfit for human consumption. Another major casualty was the tourist industry in Northern France, with holidaymakers staying away from the polluted beaches, which took many months to fully recover.
The total cost of the disaster, in damages to the environment, ecology and the economy, was put at over £200m. Some lessons were learned from the disaster, in terms of dispersing the oil, cleaning up beaches and rescuing wildlife, but it didn’t stop other supertanker disasters in the years that followed. Although Amoco Cadiz remains physically the biggest ship to be wrecker, some of the later disasters resulted in bigger oil spills.
The wreck of the Amoco Cadiz, split into three main parts, remains on the sea bed and, ironically, has become an important habitat for some types of sea life. Diving on or near the wreck is strictly controlled due to the bombs dropped into it which failed to explode.