In 2007, EarthRights International brought suit on behalf of twenty-five indigenous Achuar plaintiffs from the Peruvian Amazon against Los Angeles-based Occidental Petroleum Corp. (Oxy), alleging egregious harm caused by Oxy over a thirty-year period in the Corrientes River basin during which Oxy contaminated the rivers and lands of the indigenous Achuar communities, causing death, widespread poisoning and destruction of their way of life.  ERI and its co-counsel also represent the California-based NGO Amazon Watch, which is also suing Oxy for unfair business practices in covering up the contamination.  The Oxy lawsuit was dismissed by the federal District Court in Los Angeles in 2008; the judge ruled that under the doctrine of "forum non conveniens," the case should be litigated in Peru instead of the United States.

The plaintiffs appealed to the Ninth Circuit Court of Appeals, arguing that the case should stay in the United States, and that the district court should have granted some discovery before dismissing the case.  Oxy also cross-appealed, arguing that Amazon Watch has no standing to sue, and should be dismissed from the case.

On December 6, 2010, the Ninth Circuit reversed the district court's ruling, finding that the case should stay in Los Angeles.  The Ninth Circuit did not rule on Amazon Watch's standing to sue, instead ruling that the district court should consider that question. Oxy then filed a petition for rehearing at the Ninth Circuit, challenging the appeal decision.  On June 1, 2011, the Ninth Circuit issued a new opinion, addressing some of Oxy's criticisms but not changing the result of the appeal; the amended opinion still decided that the case should stay in Los Angeles. Oxy has filed a second petition for rehearing challenging the new opinion.

In addition to EarthRights International (ERI), counsel for the plaintiffs include Schonbrun DeSimone Seplow Harris Hoffman & Harrison LLP and Natalie Bridgeman Fields.