There are around 2,000 official spill sites in the region, some of them decades old.
Oil companies operating in the region blame thieves and sabotage for the majority of the spills, though local activists say aging equipment and lax safety are the cause of many of them. The number of severity of the spills may actually increase in coming years as the industry moves into more remote and difficult terrain in the delta.

It's not just the spilled oil that can be dangerous. Pipeline explosions, like in the one that killed more than 100 people outside Lagos in 2008, are increasingly frequent as well.