A group of Ecuadorean Indians has filed a billion-dollar lawsuit against US oil giant, ChevronTexaco.
They accuse the company of destroying large areas of the Amazon jungles and polluting the environment.
The Indians have also alleged the pollution has caused an increased rate of cancer in the population.
Indian groups are demanding ChevronTexaco spend $1 billion to clean up oil-laden water allegedly dumped by a subsidiary in the first time the decade-old case will be heard in Ecuador.
The Indians' lawyers say Texaco Petroleum Co. dumped 18.5 billion gallons(70.3 billion litres) into unlined pits, estuaries and rivers between 1972 and 1992.
Plaintiffs say Texaco should have re-injected oily water into the ground instead of releasing it into the environment.Plaintiffs said the release saved the company $4 billion.
ChevronTexaco argues its water-treatment techniques were allowed in Ecuador and other nations and that it has paid for a $40 million clean-up project approved by the government.
The Texaco case has fueled suspicion of oil companies among many Ecuadorean Indian communities and contributed to violent protests aimed at keeping firms out of the Amazon.
Texaco, which merged with Chevron in 2001, said it treated produced water in a three-stage process before releasing it into the environment and that re-injection was not required.
The case was first filed in 1993 in the United States. But the US Second Circuit Court of Appeals affirmed a ruling dismissing the suit on jurisdictional grounds last year and said that "Ecuador would be a more convenient location" for it to be heard.