A group of American lawyers representing more than 30,000 indigenous people in Ecuador filed a $1 billion lawsuit against the ChevronTexaco Corporation yesterday. The suit was filed in Ecuador on behalf of 88 plaintiffs in Lago Agrio, a small oil town in northern Ecuador, and asserts that during two decades of operation, from 1971 to 1992, ChevronTexaco dumped over four million gallons a day of toxic wastewater, contaminated with oil, heavy metals and carcinogens into open pits, estuaries and rivers. It also says the company left behind nearly 350 open waste pits that killed people and animals.