Revealed: Trafigura-comissioned report into dumped toxic waste

After a five-week legal battle the Guardian can finally publish details of the Minton Report, a scientific study commissioned by oil trading company Trafigura about its own waste dumping in west Africa that had been leaked to the newspaper.

The report contains damning evidence of the potentially toxic nature of the waste Trafigura dumped in Abidjan in the Ivory Coast.

The draft report originated in September 2006 when Trafigura's then lawyer, a man called Mark Aspinall from the shipping specialist Waterson Hicks, commissioned the scientific consultant Minton, Treharne and Davies to produce a highly confidential study of exactly what had happened when hundreds of people in the Ivory Coast besieged hospitals claiming they had been poisoned.

The scientist John Minton wrote the report with confidential data about the cheap and dirty chemical process Trafigura had used to try to reduce the sulphur content of a consignment of contaminated gasoline it had bought cheaply.

The Minton report – though it was preliminary in nature – made dismaying reading for Claude Dauphin, the Trafigura director in charge of oil preparations. It said the process had been so amateurish that it had probably left a high quantity of noxious sulphur compounds in the vast quantity of stinking black waste.

Minton went on to list half a dozen potentially unstable chemical compounds which could burn or poison people who came into contact with them. Some of them could also generate the killer gas hydrogen sulphide in certain conditions.

Minton said such waste could never have been dumped legally on a landfill in Europe and ought to have received specialist and expensive chemical treatment called "wet air oxidation" to make it safe. None of this had happened.

Among the effects of the sludge, Minton listed: severe burns to the skin and to the lungs; permanent ulceration; corneal damage; vomiting, diarrhoea, loss of consciousness and death. One of the chemicals was branded "very toxic to humans and dangerous to the environment".

The report was so dismaying to Trafigura that the company concealed its existence. The contents were never disclosed to the other side when lawyers for 30,000 claimants from the Ivory Coast brought a huge compensation suit.

The explanation for this was that the report had been superseded by further evidence from experts whom the firm had consulted for the purposes of the litigation, and whose evidence was preferred. Those experts and their reports have never been revealed, after a confidential settlement of the case last month.

When the Guardian discovered the existence of the Minton report and asked the author if it was genuine, Trafigura's response was to take the Guardian to court and get an injunction to suppress it.

Although the injunction kept the report secret, the document was in the possession of others, including Greenpeace, Norwegian Television and the whistleblowing website, Wikileaks.

Last night Pierre Lorinet, Trafigura's chief financial officer, told The Daily Telegraph: "Effectively that report was a draft report ... an analysis of possibles. We decided that our best course of action at the time was to get the injunction, because we didn't want more inaccurate reporting on things which are very clearly wrong effectively. It is a heavy-handed approach, absolutely. With hindsight, could it have been done differently? Possibly. The injunction was never intended to gag parliament or attack free speech."