In a world criss-crossed by seaborne trade, decisions in one region can have serious repercussions for others. The current voyage of the Russian tanker Geroi Sevastopolya, from Europe to Asia, is a case in point.
The vessel, carrying 50,000 metric tonnes of heavy fuel oil from Latvia to Singapore, was warned by Spain this week to stay several hundred kilometres away from the Spanish coast on its way south.
The European Union recently banned the Geroi Sevastopolya, and other heavy-oil carriers like it, from EU waters. With tougher rules on single-hull tankers now in place in Europe, it is likely they will become even more heavily engaged in carrying oil to Asia, where the breakneck pace of China's economic expansion is leading to a huge surge in oil imports. Some critics have likened old and badly maintained tankers to environmental time bombs. The Spanish government is still smarting from the public outcry when another tanker, the Prestige, broke in two in a winter storm just over a year ago and sank about 245 km off the northwestern coast of Spain, spilling much of its 63,000 tonnes of heavy fuel oil into the sea. It fouled the Spanish coastline for months afterwards.
Like the Geroi Sevastopolya, the Prestige was en route to Singapore. Both tankers are well over 20 years old and have single steel hulls. Large modern tankers have double hulls, for added protection in case of rough weather, a collision or grounding.
In fact, over half of the world's 10,000 tankers are the old-style, single-hull variety despite outcries after every major oil spill in recent years, from the 1989 Exxon Valdez in pristine Alaska to the Erika, which went down off the west coast of France in 1999.
The Prestige sinking galvanised Europe's political leadership to take tough action. The European Union last October banned single-hull tankers from the ports, offshore installations and waters of its 15 member states if they were carrying heavy grades of oil.
Heavy fuel oil will not disperse or emulsify easily when treated with detergents to clean up a spill. And it tends to stick to the seafloor, resulting in the long-term contamination of shellfish beds and the closure of parts of fisheries around inlets where a lot of oil has settled.