The documents are ugly and embarrassing. In e-mails riddled with terms like “gasoline slops” and “caustic washing,” officials with Trafigura, a major global commodities trading firm, described plans to clean and re-sell contaminated oil from Mexico and deposit the wastes in Africa, since they were too toxic for regulators in Europe or the U.S. In one 2005 e-mail discussing oil-cleaning profits, Trafigura staffer James McNicol wrote, “This is as cheap as anyone can imagine and should make serious dollars.”

But what made it so “bloody” cheap, as another e-mail put it, was Trafigura’s decision to wash the oil on its own rather than pay for a full-fledged cleaning, and then pay a trucking outfit to dump the waste. The consequences were dire. Written throughout 2005 and 2006, the e-mails were part of a paper trail that Trafigura would later seek to hide from public view with help from British courts, which have become increasingly unkind to press freedoms—until a social-media protest of tweets and blogs forced the company to cease its efforts to keep the material secret.

Trafigura touts itself as one of the largest independent commodity traders on the planet—and the third-largest oil trader—with operations in forty-two countries. The corporation’s charitable arm, the Trafigura Foundation, prides itself on “making a real difference by creating genuine, positive and lasting changes in the societies, communities and projects it supports.”

Not in Abidjan, however. En route to its eventual home in the capital of Ivory Coast in 2006, the waste—a putrid black slurry of oil refuse containing caustic soda, sulfur, and hydrogen sulfide—traversed the globe. It started in Houston, Texas, and stopped in Estonia and later Amsterdam, where port officials insisted the mix was too toxic for dumping and would have to undergo cleansing. But Trafigura “balked” at the $300,000 cost, according to an October 2, 2006, story in The New York Times. The company then sought an easier regulatory climate in Africa. An Amsterdam port official would tell the Times, “We have never handed back or refused waste before. But the crux was that Trafigura refused to pay. If they had, the material would have been treated and there would have been no problem.”

As Trafigura officials hashed out the easiest way to dispose of the slops, an employee named Naeem Ahmed noted, “caustic washes are banned by most countries due to the hazardous nature of the waste.” Solution? McNicol would soon propose that Trafigura hire an outside firm and “pay these guys to take the shit away.” In March 2006, staffer Leon Christophilopoulos suggested, “I don’t know how we dispose of the slops and I don’t imply we would dump them, but for sure, there must be some way to pay someone to take them.”

And there was. In the middle of an August night in 2006, a trucking outfit hired by Trafigura dumped about a dozen tanker truckloads—roughly 400 to 500 tons—of the stinking waste in sites throughout Abidjan, a city with some 4 million people. Soon, local clinics swelled with tens of thousands of Ivorians complaining of nausea, vomiting, skin sores, nosebleeds, and other ailments. A report by U.N. investigators documented more than a dozen deaths that it alleges were connected to fumes from the waste. Trafigura has consistently rejected claims that the waste dumped by the trucker caused illnesses or deaths.

Christopher D. Cook is an independent journalist in the United Kingdom and the author of Diet for a Dead Planet: Big Business and the Coming Food Crisis, published in 2004.