An Ecuadorean judge has ruled that Chevron was responsible for oil contamination in a wide swathe of the country’s northern jungle and fined it at least eight billion US dollars (£5 billion), the plaintiffs’ lead attorney said.
Chevron said it would appeal and called the ruling “illegitimate and unenforceable” in a news release.
The plaintiffs’ lawyer, Pablo Fajardo, called the judgment “a great step that we have made toward the crystallisation of justice”.
But he added that he considered the damage award too low and was also considering an appeal.
Mr Fajardo said he had just received the 187-page ruling and needed to digest it before commenting further.
Chevron has long contended that the court-appointed expert in the case was unduly influenced by the plaintiffs.
In its statement, the corporation called the ruling “the product of fraud (and) contrary to the legitimate scientific evidence”.
The suit stems from damages sought on behalf of 30,000 people for environmental contamination and illnesses that allegedly resulted from Texaco’s operation of an oil consortium from 1972 to 1990.
Chevron bought Texaco in 2001.