The U.S. oil company Chevron is facing a class action lawsuit that accuses it of polluting Ecuador's rainforest.

In a court in Lago Agrio, northeast of Ecuador's capital, Quito, Chevron's lawyers criticized the billion-dollar class-action suit by 30,000 Amazon Indians.

The plaintiffs allege that Texaco, a U.S. oil company acquired by Chevron, dumped oily waste-water into local rivers from 1972 to 1992. They are demanding the company clean up the pollution, which they say has caused cancer, killed livestock, and ruined crops.

Chevron's lawyers say the company followed appropriate practices under an agreement with the state-owned oil firm Petroecuador. They say Chevron has already funded a $40-million clean-up project.

The Amazon Indians first filed the suit in a U.S. federal court in 1993, but judges in 2002 ruled that an Ecuadorian court should try the case.

Some information for this report was provided by AP and Reuters.