In a forsaken little town in the Ecuadorean Amazon, an overgrown oil camp called Lago Agrio, the giant Chevron Corporation has been maneuvered into a makeshift courtroom and is being sued to answer for conditions in 1,700 square miles of rain forest said by environmentalists to be one of the world's most contaminated industrial sites. The pollution consists of huge quantities of crude oil and associated wastes, mixed in with the toxic compounds used for drilling operations—a noxious soup that for decades was dumped into leaky pits, or directly into the Amazonian watershed. The company that did much of this work was Texaco—an outfit with a swashbuckling reputation worldwide. It signed a contract with Ecuador in 1964, began full-scale production in 1972, and pulled out 20 years later. In 2001, Texaco was swallowed whole by Chevron, which by integrating its operations nearly doubled in size. The lawsuit against it in Lago Agrio was filed in 2003, though the legal antecedents go back much further. Having dragged on for four years, the suit may continue for half again as long. Chevron is represented by high-priced firms of experienced lawyers in Quito and Washington, D.C., whose collective fees run to millions of dollars annually. Its antagonists are 30,000 Amazonian settlers and indigenous people, who call themselves Los Afectados—the Affected Ones. These plaintiffs are represented by a low-budget but serious team of North American and Ecuadorean attorneys, who are backed by a Philadelphia law firm that is known for class-action securities litigation and has gambled that this case, though risky, can actually be won.

Chevron objects vociferously, and presents itself as the victim here. Its attorneys have repeatedly claimed that the company is being extorted for "two juicy checks," one to be divided among the plaintiffs and the other to enrich their North American lawyers. The North American lawyers are indeed working on a contingency basis, but unapologetically so, and for a percentage significantly lower than the norm in high-risk cases; they would like to be well compensated for their efforts, but as much, they say, to encourage other lawyers to bring similar suits elsewhere in the world as to pad their personal bank accounts. The most active among them is a New York–based Harvard Law School graduate named Steven Donziger, who has invested 14 years in the case and would certainly be more secure had he pursued a conventional career involving the preservation of wealth. He counterclaims that Chevron's lawyers are the real mercenaries here. It is a philosophical quarrel that will never be resolved.

As for the plaintiffs themselves, under Ecuadorean law they are not suing individually, and personally may never see a dime. They have sued to seek compensation for past damages and to force Chevron to clean up the residual mess that continues, they believe, to taint the soil and water today. It is unclear how a cleanup would proceed and to what extent it could succeed, but over decades the cost might run to $6 billion or more—making this potentially the largest environmental lawsuit ever to be fought. And fight is the word. The case has become emotional for both sides, with few signs of willingness to compromise. Worldwide the oil industry is watching. Lago Agrio is a forsaken little town where something rather large is going down.

This is not, however, a U.S.-style legal drama. The Lago Agrio court follows Ecuadorean procedures, which minimize oral arguments and rely heavily on submitted documents to get at the truth. So far the proceedings have generated close to 200,000 pages. There is no jury to sway. There is a single presiding judge, drawn from a pool of three on a rotating basis for a two-year term of unusual pressure. Currently the judge is a rotund middle-aged man, a reader of Dostoyevsky and a convert to Islam. He must be the only Muslim in town. He told me it is not easy to be a judge there. Five years ago he was ambushed and machine-gunned while driving his car. His companion was killed, but he himself escaped. The attackers were hired killers, of whom Lago Agrio has an ample supply. Colombia's largest cocaine-production area lies just over the border a few miles to the north, and is peopled not only by narco-traffickers but also by leftist guerrillas and right-wing paramilitary groups. The police in Lago Agrio make a show sometimes of directing traffic. They did not investigate the attack, the judge believes, because they feared retribution. The judge accepted this without complaint, as if he had learned to believe in fate. Lago Agrio means "sour lake." He told me that the only safe choice there is to run away. Chevron would probably agree. It denies that the judge is fair, denies that the plaintiffs have legitimate complaints, denies that their soil and water samples are meaningful, denies that the methods the company used to extract oil in the past were substandard, denies that it contaminated the forest, denies that the forest is contaminated, denies that there is a link between the drinking water and high rates of cancer, leukemia, birth defects, and skin disease, denies that unusual health problems have been demonstrated—and, for added measure, denies that it bears responsibility for any environmental damage that might after all be found to exist. If Chevron can convince the court of the validity of even a few of those points, it will win the case and leave town.