Chevron has been fined $8bn (£5bn) after a judge ruled the oil company was responsible for contaminating the Amazon basin in Ecuador.
It is the result of a lawsuit that has run for the last 18 years on behalf of 30,000 people who allegedly suffered health and environmental problems after waste water containing chemicals was dumped in the region by Texaco between 1972 and 1990.
Chevron, which bought Texaco in 2001, has labelled the ruling as "fraud."
Pablo Fajardo, the plaintiffs' lawyer, has indicated the case may yet go to appeal as the ruling is below the $27.3bn the plaintiffs were seeking.
The plaintiffs allege that Chevron should be held responsible for the health and economic impact of Texaco's Ecuadorian operations in the 1970s and 1980s, in what has been dubbed the "Amazon Chernobyl."
Texaco, which partnered with government oil company PetroEcuador to drill wells in the region in the 1970s, was ordered to spend $40m cleaning up the area after it ceased operations there in the 1990s.
The company claim they were legally released from any further responsibility after the clean-up but the lawsuit alleges that the operation failed to address the widespread damage caused by faulty drilling practices.
The long-running case, which has attracted high profile coverage, was the subject of the 2009 documentary Crude and has gained support from celebrity campaigners such as Sting and Daryl Hannah.
The case has also triggered numerous related court cases including this month's arbitration case at The Hague in which Chevron lawyers claimed a group of trial lawyers and consultants were attempting to manipulate the Ecuadorian court system.
Chevron has claimed the judgement is "illegitimate and unenforceable" and "the product of fraud and is contrary to the legitimate scientific evidence." The company intends to appeal against the ruling.
Speaking after the ruling, Fajardo suggested that the plaintiffs may appeal, and said "the plaintiffs will take whatever actions are appropriate consistent with the law to press the claims to a final conclusion."
Judge Nicolas Zambrano has given Chevron 60 days to set up an escrow account to distribute the damages.