Internal emails show that Trafigura, which yesterday suddenly announced an offer to pay compensation to 31,000 west African victims, was fully aware that its waste dumped in Ivory Coast was so toxic that it was banned in Europe.
Thousands of west Africans besieged local hospitals in 2006, and a number died, after the dumping of hundreds of tonnes of highly toxic oil waste around the country's capital, Abidjan. Official local autopsy reports on 12 alleged victims appeared to show fatal levels of the poisonous gas hydrogen sulphide, one of the waste's lethal byproducts.
Trafigura has been publicly insisting for three years that its waste was routine and harmless. It claims it was "absolutely not dangerous".
It has until now denied compensation claims, and its lawyers repeatedly threatened anyone worldwide who sought to contradict its version. It launched a libel case against BBC Newsnight, forced an alleged correction from the Times, demanded the Guardian delete articles, and yesterday tried to gag journalists in the Netherlands and Norway with legal threats.
But the dozens of damning internal Trafigura emails which have now come to light reveal how traders were told in advance that their planned chemical operation, a cheap and dirty process called "caustic washing", generated such dangerous wastes that it was widely outlawed in the west.