However, international commodities trader Trafigura said the settlement was in no way an admission of liability.

A group representing the victims, who all live near the city of Abidjan in the Ivory Coast, said it rejected the offer, and accused the company of exploiting Africa’s poverty to end the row and avoid taking responsibility.

Trafigura, one of the world’s biggest commodities traders, with offices in London, Geneva and Amsterdam, has repeatedly denied any wrongdoing in relation to the 2006 incident, when slops from a cargo ship it had chartered were dumped in Abidjan, the Ivory Coast capital.

In the weeks that followed the dumping, tens of thousands of people reported a range of similar symptoms, including breathing problems, sickness and diarrhoea.

Denis Pipira Yao, president of the Ivorian National Federation of Victims of Toxic Waste says Trafigura wants to excuse itself morally but it is not fair

Last week a United Nations report said that on the face of it, there was a strong link between the waste and the deaths of at least 15 people and illness suffered by thousands more. Trafigura called the report "deeply flawed".

The company agreed to a $198m out-of-court settlement with the Ivory Coast government in 2007, which exempts it from legal proceedings in the West African country. Trafigura said in a statement that Leigh Day and Co, a London law firm representing the victims, accepted that experts were unable to identify a link between the slops deposited and any deaths, miscarriages, still births or other serious injuries.

The slops "could at worst have caused a range of short-term, low-level flu-like symptoms and anxiety", it said.

Eric De Turckheim, a co-founder of Trafigura, said the settlement vindicated the firm’s stance that the toxic waste did not cause any deaths.

But the Ivorian National Federation of Victims of Toxic Waste, which says it represents nearly all the victims, accused Trafigura of trying to push through the agreement to avert a class action case due to be heard in a London court next month.

"Trafigura wants to excuse itself morally but it is not fair," Denis Pipira Yao, the group’s president, told reporters.

"The waste was toxic and lethal. Trafigura is proposing 750,000 CFA francs (US$1683) for each victim," he said. "As people are poor in Africa, Trafigura is using money to get away with it. We are not at all happy with this way of doing business and we will work with our lawyers to make it clear."

It was not clear why the compensation figure he cited was different from that stated by Trafigura.

De Turckheim declined to respond directly to Yao’s comments, saying Trafigura’s settlement was with the 31,000 claimants represented by Leigh Day and Co.

Trafigura hired a contractor in 2006 to dispose of slops from a ship it had chartered, the Probo Koala. It described the petrochemical waste as residues from gasoline mixed with caustic washings.

Trafigura said in a press release that the settlement was "in no way an acceptance of liability" but a sign of its social and economic commitment to the region.

"Trafigura also recognises that the slops had a deeply unpleasant smell and their illegal dumping . . . caused distress to the local population." – Reuters