UPDATE 1-U.S. judge rules for Chevron in Ecuador environmental case

NEW YORK, March 4 (Reuters) - An American lawyer used "corrupt means" to secure a multi-billion-dollar pollution judgment against Chevron Corp in Ecuador, a U.S. judge ruled on Tuesday, handing the oil company a major victory following a six-week trial last year.

In a nearly 500-page decision, U.S. District Judge Lewis Kaplan in New York said he had found "clear and convincing evidence" that attorney Steven Donziger's legal team bribed an Ecuadorean judge to issue an $18 billion judgment in 2011 in favor of a group of villagers. They had claimed Texaco, later acquired by Chevron, contaminated an oil field in northeastern Ecuador between 1964 and 1992.

Ecuador's high court cut the judgment to $9.5 billion last year.

Kaplan's decision bars Donziger and the villagers from enforcing the Ecuadorean ruling in the United States and freezes all proceeds from the judgment.

Chevron had accused Donziger of fraud and said Texaco cleaned up the site before handing it over to a state-controlled entity.

Donziger, who had leveled accusations of bias against Kaplan repeatedly and predicted he would lose the case, did not immediately comment on the decision. A Chevron spokesman also did not immediately comment.

Kaplan's ruling only bars the Ecuadorean plaintiffs from collecting on the judgment in the United States, and the villagers have pursued claims against Chevron in other countries, including Canada, Argentina and Brazil.

Chevron, however, could try to use the decision to defend itself against claims abroad.

The decision caps a years-long battle in U.S. courts between Chevron and Donziger, pitting the company's vast resources against a lawyer who argued he was the victim of an unscrupulous corporation.

But Kaplan found that the evidence against Donziger was "voluminous."

Kaplan said Donziger began pursuing the case with intentions to improve environmental conditions in Ecuador and make a living for himself, but ultimately corrupted the case by submitting fraudulent evidence, bribing a judge and covering up his wrongdoing.

"Justice is not served by inflicting injustice," Kaplan wrote. "The ends do not justify the means. There is no 'Robin Hood' defense to illegal and wrongful conduct."

Kaplan oversaw the non-jury trial, which ended in November.

The case is Chevron Corp v. Steven Donziger et al, U.S. District Court for the Southern District of New York, No. 11-0691.