Public health hazards from the use of agricultural pesticides have received increasing attention in developing as well as industrial nations. This article examines a remarkable case of massive sterilization of approximately 1,500 workers in Costa Rica, due to exposure to a toxic nematicide called DBCP 1,2-dibromo-3-chloropropane), applied in large commercial banana plantations. Although the product was used during the 1970s, sterile victims have continued to be diagnosed through the 1980s. The effects include psychological trauma as well as permanent infertility. The case has international repercussions because several hundred workers have filed law suits against the U.S.-based transnational DBCP manufacturers, and because DBCP use was continued during the 1980s in other developing nations. The author analyzes the causes behind this serious impairment. It is argued that the contributing factors include not only biomedical processes and technical dimensions (i.e., how DBCP was used), but most importantly, political-economic factors that explain how and why DBCP was used despite the severe hazard. The crucial determinants pertain to the dominance of short-term profit motives, and the control over information and technology by the manufacturers (who concealed early toxicological research evidence of the reproductive hazards) and by the managers of the banana producer-companies. This case well illustrates problems and injustices from labor exploitation and resource extraction from transnational agro-industries. The article concludes with a brief summary of policy implications from the case.