The Abidjan 2006 Toxicity Incident: a Scientific Approach



Draft: Sunday, 25 October 2009


In August 2006 the m.v. Probo Koala, chartered by the oil company Trafigura, transferred 500 tonnes of what Trafigura describe as "slops", which were in fact waste products from the processing of coker naphtha at sea, to a newly set up Ivorian disposal company, Compagnie Tommee, who discharged the waste to landfill and water courses around the town of Abidjan, Cote d'Ivoire.. The port of Amsterdam had earlier required that a costly cleaning process should be applied to the cargo, which Trafigura was not willing to pay.

Up to 100,000 people in the town reacted to the foul smell of the dumped waste. There were 30,000 medical consultations, with headaches, nausea, skin burns and respiratory tract irritation being common presentations.

Up to 17 deaths were claimed to be associated with the event.

Trafigura have paid US $198 million to the Ivorian government for a cleanup operation, and £30 million to the victims of the incident. Both payments were out-of-court settlements, and the company denies any causal relationship between its "slops" and any symptoms beyond transient flu-like illness.

The Minton Report was commissioned by Trafigura on 7 Sept 2009 and delivered on the 14th September. They were asked to assess the potential toxicity of the discharge.

In the conclusions they write:

9.3 The compounds ... are capable of causing severe human health effects through inhalation and ingestion. These include headaches, breathing difficulties, nausea, eye irritation, skin ulceration, unconsciousness and death. There would also be a strong and unpleasant odour over a large area. All of these effects were as reported in this incident.

Trafigura claim that this report was a mere draft. However, it is not presented as such. It concludes with the line:

This report was prepared prior to the arrival of documents providing details of events at the discharge and will be updated in due course.


Trafgura tried unsuccessfully to stifle reporting of their report, using the English libel laws and the notorious libel lawyers Carter-Ruck to place a super-injunction on the Guardian Newspaper from reporting a Parliamentary question on the Minton Report. A super-injunction is one that not only commands the hiding of information, but also hid the fact that an injunction had been issued*. This draconian attack on public interest knowledge was overthrown by social media activity on the internet.

As well as the abortive attempt through Carter-Ruck to gag reportage on Parliament, Trafigura are also suing BBC Newsnight for alleging that they caused illness. They have tried, or may try to, gag media sources in the Netherlands and Norway. On the other hand, Greenpeace Netherlands may sue Trafigura, and the EU Environment Commissioner, Stavros Dimas, stated that EU law had been broken by Trafigura. Remarkably, they also threatened to sue Martyn Day, the solicitor in the class action against Trafigura, for claiming that they caused illness.

Trafigura claims that the evidence of more than 20 independent experts shows that their "slops" could not have caused the observed illness. This evidence has no scientific status since it is not available for the scientific community to examine.

The central question for scientists is this:

Did Trafigura's toxic waste discharged around Abidjan in 2006 cause the illnesses claimed by the local people?

Trafigura claim not, but their claim has no scientific basis, because the evidence they claim proves no-effect is not open to access by medical and scientific investigators.

It is always difficult to make a causal link between an environmental toxin and associated ill-health.

The usual point in the case advanced by the polluter is that "There is no proof that toxin X brought about health effect Y". This is disingenuous, because, contrary to popular belief, there is no such thing as "proof" in science. According to Popper, the doyen of the philosophy of science, the best that a scientific hypothesis can achieve is "not yet dispoven".

Two years after the event, when the toxins have been neutralised, cleaned up and dissipated, it is going to be even harder to establish causality. Nevertheless, given the political will and the resources, it is still possible to design a trial to test Trafigura's hypothesis that there is no persistent health effect from their "slops".

The Design of a Trial to test the Trafigura hypothesis

Trafigura's hypothesis of no lasting damage predicts that nobody that was in contact with the airborne or water borne pollution has any persisting symptoms, signs, or evidence of change in their medical status two or more years after the pollution event. Trafigura's lawyers will probably imply that any persistent symptoms are functional, that is, manifestations of anxiety, conversion disorder, or profit-driven malingering.

This hypothesis can be tested in the following way:

1) Assemble two cohorts of people: one composed of those who believe that they have been affected by the Trafigura dump, and a control group, of similar ethnicity and socio-economic standing, but who were not exposed to the dump.

2) Collect and collate the history, (including the extent of exposure), symptoms, signs and special investigations in both groups.

- Symptoms can be registered on a questionnaire.

- Signs will be through physical examination. We will be looking primarily for current skin lesions or scarring, and at respiratory tract function.

- Investigation will consist of:
Blood tests: FBC and film, Viscosity or ESR, TFT, LFT, yGT, Electrolytes, AutoImmune profile, Immunoglobulin electrophoresis, Calcium, Glucose, and any other tests which toxicologists may suggest.

Respiratory tests on any who claim respiratory symptoms or have chest signs: Peak Flow, and Spirometry.

Biopsy of skin lesions.

Any other appropriate investigations suggested by earlier findings.

3) Analyse the data. It is probable that three groups will emerge: the control group, a group showing physical changes, and a third group who have "subjective" illness, but no objective changes, apart from a lowered free calcium level associated with hyperventilation.
4) A further test can be carried out on the groups. A sample of them can, with permission, be challenged with a reconstructed mixture of the toxins that they met in 2006. This would entail reconstructing a mixture of the Probo Koala's waste, as best we can from the records and our knowledge of the coker naphtha process, and reacting it in a laboratory with the kind of liquids and solids that are found typically in the waste tips around Abidjan. The FBC, film, immunoglobulin profile and viscosity, and other relevant immunological parameters in both experimental groups will be measured before and after the challenge.

The causal hypothesis predicts that the physically affected group will show a change in the markers, while the controls and "subjective illness" group will have no such reaction, or a different reaction.
5) The data can be analysed, and Bradford Hill's criteria applied to the results, so far as is possible.

Clearly, this trial would be a major undertaking, costing a few millions of pounds, and is well beyond the reach of the government of the Cote d'Ivoire, or of NGOs. However, Trafigura has shown itself ready to make "ex gratia" payments already, and may be prepared to provide funds, which can be accepted provided that they are on an arms'-length basis. An alternative source of funding would be Trafigura's insurance company, since they must have corporate insurance to cover this eventuality.

The scientific approach to the question of whether Trafigura's 2006 dump of waste in Abidjan had an adverse effect on the health of local people involves a careful survey of the current health of the exposed population, compared with a similar number of non-exposed people. This survey should be paid for at arms length by Trafigura's insurers.

© Richard Lawson
Sunday, 25 October 2009


*"I can say only this, that I can nothing say"
Andrew Marvell

© 2001 R. Lawson