Quote
The affected five kilometre stretch of pipeline carries oil from BP's Prudhoe Bay oilfield in Alaska to the Trans-Alaska Pipeline, which connects all of Alaska's oilfields to seaports. On Sunday, BP announced plans to begin shutting down its 400,000-barrel-a-day Prudhoe operations while it replaces 25 kilometres of suspect piping. BP officials say the best guess so far is that bacteria colonised part of the pipe and corroded the metal. A similar problem probably led to a 750,000-litre oil spill in another part of BP's Alaska pipeline in March 2006.