Working at the nexus of environmental, cultural, and Borderlands history, my research, "Smoke and Mirrors: Smelter Pollution and the Cultural Construction of Environmental Narratives in the U.S.-Mexico Borderlands," follows the evolving late 20th-century debates over transnational smelter pollution in southern Arizona and northern Sonora, Mexico. The region has pivoted around copper mining since the late 19th century and by the mid-1900s, the transnational copper industry, concentrated in Douglas, Arizona, and Cananea and Nacozari, Sonora, coupled with the prevalence of maquiladoras in Agua Prieta, produced a severe air pollution problem. In reaction to environmental damage and public health problems, concerned citizens on both sides of the border organized to legally enforce existing environmental regulations and improve local conditions. The ensuing struggle over local air quality in the small towns of Douglas, Cananea, and Nacozari--coined the "Gray Triangle"--quickly escalated to national environmental and economic conversations, and resulted in international cooperation and legislation.