This dissertation examines the relationship between organized labor and the mainstream environmental movement in the United States between 1970 and 1985. It explores this relationship through the critical lenses of three issues (economic development, energy, and occupational safety and health), which were central to nearly all interactions between organized labor and environmental organizations in this period. I argue that, contrary to popular belief, the two movements collaborated with one another consistently throughout this period. Their cooperative activity, sustained through considerable effort, was partially responsible for building and maintaining the nation's environmental regulatory framework at the close of the twentieth century.