An investigation by Amnesty International and Greenpeace has found Western governments failed to prevent the dumping of toxic waste in Ivory Coast in 2006.
Trafigura, a Dutch-based transport company, paid a newly formed Ivorian company to dump the waste around the port of Abidjan.
Altogether, 100,000 people sought hospital treatment.
The campaigners argue the British and Dutch authorities failed to prevent the dumping or to hold Trafigura to account.
The company denies any wrongdoing and says the report contains significant inaccuracies and misrepresentations.