Oil firms and government say nearly 200,000 barrels of oil stolen each day from pipelines and wells by criminal gangs.

A sophisticated criminal network has stepped up its operations in Nigeria’s Bayelsa State, costing state and oil companies as much as a billion dollars per month.

Royal Dutch Shell Oil Company’s Nigerian subsidiary said in a recent report that between 150,000 and 180,000 barrels of oil are stolen each from its pipelines and wells. Government estimates have put the number of stolen oil as high as twice this amount.

The trade in stolen oil involves international traders who provide oil at discounted prices to refineries in other parts of the world.

Al Jazeera’s Mohammed Adow, reporting from Nigeria’s Bayelsa State, said the impact of oil theft on the environment was devastating.

Adow witnessed what he called “effectively a crime scene” and “rivers covered by thick films of oil” while on a helicopter tour of the region.

“Vegetation in this once heavily forested region is also devastated by frequent spills and explosions,” Adow said.

Philip Mshelbila of Shell Oil in Nigeria told Al Jazeera, “cleaning up what has already occured would be futile unless you stop more from happening”.

Meanwhile, the men responsible for the oil theft say they will cease their actions only if the government offers support to the people of the oil-rich region of western Africa.

“It’s stealing, we know, but if the federal government can help us then we will leave this [work] entirely,” said Ibegi Alakoroa, an oil thief in Bayelsa State.

Dodging responsibility

On Friday, Amnesty International said investigations into Shell Oil spills were a “fiasco”, alleging the company repeatedly blamed sabotage in an effort to avoid responsibility.

“No matter what evidence is presented to Shell about oil spills, they constantly hide behind the ‘sabotage’ excuse and dodge their responsibility for massive pollution that is due to their failure to properly maintain their infrastructure,” Audrey Gaughran, director of global issues at Amnesty, said in a statement.

She said “the investigation process into oil spills in the Niger Delta is a fiasco”, referring to the region that is home to Africa’s largest crude industry.

The London-based rights group accused the Anglo-Dutch oil giant of ignoring evidence that the latest spill in the Delta’s Bodo Creek area, discovered in June, was caused by pipeline corrosion.

Bodo Creek saw two major oil spills in 2008 over which the Anglo-Dutch petroleum giant is being sued in a London court by 11,000 Bodo residents.

An official from Shell’s Nigerian subsidiary told the AFP news agency the company was not ready to comment on the latest allegations.

In the statement, Amnesty said it hired the US company Accufacts to examine pictures of the Bodo Creek pipeline over the June spill.

According to Amnesty, the company said it noticed a “layered loss of metal on the outside of the pipe,” which is “a very familiar pattern” consistent with corrosion.

“Shell have said locally that the spill looks like sabotage, and they completely ignore the evidence of corrosion,” said Stevyn Obodoekwe of the Centre for Environment, Human Rights and Development, which co-authored the Amnesty statement.