Oil development in the Ecuadorian Amazon since the early 1970s has resulted in widespread contamination of the area with toxic and carcinogenic wastes. Indigenous residents and colonists of the region are plaintiffs in an international class action mass toxic tort lawsuit filed in US courts against Texaco Corp., the entity believed by the plaintiffs to be responsible for the damages. Field research will evaluate the differential impact of the lawsuit on indigenous and colonist communities, assess the incorporation of scienti­fic data generated by the lawsuit into local categories of knowledge, and track the effects of this lawsuit on similar international litigation.