Concerns are growing over an oil slick off China's east coast after an Iranian tanker, the Sanchi, exploded and sank a week ago following a collision at sea.

Here is a look back at the major oil spills around the world in the past five decades:

- Shipwrecks -

- Atlantic Empress and Aegean Captain, 1979: The two Greek-registered tankers collide and catch fire off Tobago in the West Indies, spilling an estimated 287,000 tonnes of crude. Thirty sailors die.

- ABT Summer, 1991: Loaded with 260,000 tonnes of crude, the Liberian-registered tanker explodes some 1,300 kilometres (900 miles) off the coast of Angola. The ship burns for three days before sinking with its cargo.

- Castillo de Bellver, 1983: The Spanish oil tanker runs aground off Saldanha Bay in South Africa, spilling 250,000 tonnes of oil.

- Amoco Cadiz, 1978: 227,000 tonnes of oil wash up on 400 kilometres of French coastline when the Liberian-registered supertanker sinks off Brittany.

- Haven, 1991: The Cypriot oil tanker sinks off Italy's Gulf of Genoa after fires destroy most of its 144,000-tonne cargo. The remainder of the oil forms a slick polluting Italy's Liguria coast and Provence in France.

- The Odyssey, 1988: The British ship carrying 132,000 tonnes of oil sinks with its 27-member crew in the Atlantic, 1,300 kilometres from the Canadian coast.

- Torrey Canyon, 1967: 121,000 tonnes of oil pollute the coast off England and France after the grounding of the Liberian-registered supertanker.

Other oil tanker shipwrecks may have involved less oil but still caused major environmental damage. These include the Exxon Valdez in Alaska in 1989, the Sea Empress off Wales in 1996, the Erika in France in 1999 and the Prestige in Spain 2002.

- Oil rig spills -

- Gulf of Mexico, 1979: Around one million tonnes of oil gush from the Ixtoc-Uno well after an explosion on a rig operated by Mexican state oil company Pemex. Capping the leak takes nine months.

- Gulf War, 1991: Around one million tonnes is estimated to have spilled when Iraqi forces set fire to Kuwaiti oil wells. Hundreds of kilometres of coastline are polluted.

- United States, 2010: The explosion of the Deepwater Horizon oil rig, operated by BP in the Gulf of Mexico, leaves 11 dead and leads to the spillage of more than 600,000 tonnes of oil.

Sources: AFP, France-based accidental water pollution expert group Cedre, International Tanker Owners Pollution Federation Limited (ITOPF)