Nigerian President Goodluck Jonathan established a special review committee last year to assess oil spills in Ogoniland attributed to Shell's subsidiary in Nigeria.
Nigerian Minister of Petroleum Resources Diezani Alison-Madueke said the government is reviewing an interim report assessing a U.N. review of oil pollution in Ogoniland, Nigerian newspaper This Day reports.
The U.N. Environment Program last year said it would likely take 30 years to clean up oil spilled in the region. Shell is accused of underestimating a 2008 oil spill.
Amnesty International estimates as much as 4,000 barrels of oil spilled in the region per day, though Shell claims the figure is closer to 1,640 barrels, the newspaper said. Furthermore, the report says, Shell claimed the spill began in October 2008, while Nigerian regulators suspected it started two months earlier.
The Nigerian report comes as Shell declared force majeure on Bonny Light crude, the Nigerian blend, as of May 4. "The action is due to production deferment caused by incessant crude theft and illegal bunkering on Nembe Creek Trunkline," the company said in a statement.
The shutdown means 60,000 barrels of oil per day is deferred while repairs take place.