A large oil spill near Nigeria's Brass facility, run by ENI, an Italian energy company, has spread through the sea and swamps of the oil producing Niger Delta region, local residents and the company said Monday.
ENI said it was not yet possible to determine the cause of the spill.
"During loading operations on a tanker on November 27, an oil spill in the sea was seen. Operations were immediately suspended and resumed only after it was verified that the vessel's structures were not damaged and were not leaking," the company said in an emailed statement, according to Reuters.
Vast stretches of the delta's unique mangrove swamps are blackened and dead from oil pollution caused by hundreds of leaks every year from pipelines that pass through the delta's creeks.
ENI in particular reported 471 spills in the Niger Delta, compared with the 138 from Shell from January to September, according to a recent Amnesty International report. ENI's Nigerian subsidiary frequently blames saboteurs, but Amnesty said there's "absolutely no information" to support their claims.
"For the last decade oil companies in Nigeria, in particular Shell, have defended the scale of pollution by claiming that the vast majority of oil spills are caused by sabotage and theft of oil," the report said. "There is no legitimate basis for this claim."
Nigerian legislators are considering a law to impose new fines on operators responsible for oil spills, a measure that could land major foreign companies with penalties running into tens of millions of dollars a year.
Francis Clinton Tubo Ikagi, chairman of the Odioama fishing community in Bayelsa, where a large part of the Niger river fans out through creeks into the Atlantic, told journalists on the scene that he saw a large oil slick on Nov. 20.
"I saw a very thick layer of crude oil on the river," he said. "The community is affected seriously. Our women and men whose main livelihood source is fishing are complaining bitterly to us that the whole river is full of oil."
While a number of spills are caused by loading accidents or decrepit infrastructure, some are also caused by theft and pipeline sabotage, a crime committed daily in the Niger Delta, where millions live in poverty.
Oil companies are required to fund the clean-up of each spill and usually pay compensation to local communities affected, if it was clearly the company's fault.
Al Jazeera and Reuters