This article analyzes how the first collective action toxic tort in Taiwanese history, Former RCA Employees’ Mutual Aid Association v. Radio Corporation of America (RCA), produced a space of deliberation about the causal effects of chronic exposure to organic solvents to human health. The author shows how this space, the collective RCA genba, was reconstructed in research laboratories, at Taipei District Court, and finally, in the judges’ verdict as efforts to understand groundwater pollution took place from various standpoints. Analysis of the media coverage, government files, scientific papers, legal documents, and the Taipei District Court verdict illuminate how a space for contestation was forged in lieu of the closed RCA factory (and RCA’s acquisition by other multinationals). At three different moments — research about RCA’s activities, the lawsuit, and the verdict—victims, industry, the legal profession, and others created and contested knowledge related to the effects of groundwater pollution. In examining the processes leading to the 2015 verdict favoring the RCA plaintiffs, this article shows how the judges reconstructed the RCA genba between 1970 and 1992. RCA offers more than a case study for examining how judges and scientists (acting as experts) engage in boundary work to construct scientific validity. Explication of the RCA case in the East Asian context has many important social and policy implications, considering the tenuous relationship between the presence of factories of multinational corporations as employers and their roles in mediating workers’ health.