A 2011 study from the U.N. Environment Program said oil contamination in parts of Nigeria have been ongoing since the late 1950s. The study said it could take as long as 30 years to clean the southeast region of Nigeria known as Ogoniland.
Shell has blamed oil thieves for affecting production to the extent that it could not meet its contractual obligations. Audrey Gaughran, a researcher at Amnesty International, was quoted by the Nigerian newspaper The Guardian as saying Shell was overstating the issue.
"Sabotage is a problem in Nigeria, but Shell exaggerates this issue to avoid criticism for its failure to prevent oil spills," she said in a report published Wednesday.
AI joined Friends of Earth International in urging the Dutch government to press Shell on its remediation obligations in Nigeria. A Dutch report said government agencies in Nigeria are "at the mercy of oil companies" when it comes to environmental issues.
The Nigerian government estimates about 250,000 barrels of oil per day is lost to sabotage and militancy. The Organization of Petroleum Exporting Countries said in a June report oil production in general was declining for Nigeria.