On July 17, 1945—one day after the Trinity Test proved that the United States government’s highly secret marathon nuclear weapons research had resulted in a usable plutonium implosion bomb—physicist Leo Szilard addressed a Manila envelope to President Harry S. Truman. The envelope contained a petition signed by 70 Manhattan Project scientists urging the Commander-in-Chief for restraint in plans to use nuclear weapons against the Japanese. Both Los Alamos director J. Robert Oppenheimer and Manhattan Project military leader Leslie Groves opposed and sought to frustrate Szilard’s work. As a result, few scientists at Los Alamos ever saw it, and the petition did not reach the President’s desk until after the bombings of Hiroshima and Nagasaki. However, the Szilard Petition testifies that even during the frenzied effort to produce the bomb, moral concerns and doubts over the geopolitical implications of its development led many of those most acquainted with its unprecedented power to try to prevent its use. Since then, every step of nuclear development has also encountered friction, whether from workers, activists, political leaders, other government agencies, or the material conditions of the non-human world. 

This path positions Colorado within the larger U.S. nuclear weapons production complex. The state’s primary contributions to the nuclear arsenal derived from the extraction of raw materials in the Uravan Mineral Belt and the manufacture of the fissile core—known as a "pit"—in the Rocky Flats plant near Denver. These activities were part of a nationally distributed bomb design, assembly, and testing network that stretched from California to South Carolina, Washington to Tennessee. However, controversies surrounding the Rocky Flats plutonium production plant are emblematic of ongoing debate and dissent surrounding the legacies of contamination and occupational illness. Its site operations—from its heyday in the Cold War to Superfund remediation—have involved an intricate web of corporate and government entanglements that limit liability, obscure public oversight, and shuttle personnel between public and private sectors and across defense companies and their joint ventures and subsidiaries. Even as the Rocky Flats works site was considered a highly secured world, apart from surrounding domestic life in Denver and its growing suburbs, the facility operated in a complex network not only with other plants in the nationally distributed U.S. bomb production line but also myriad Cold War subcontractors throughout the state of Colorado. 

This path also explores the various actors that have frustrated the smooth roll-out of both military and civilian nuclear products. Over time, such actions produced the national and international frameworks that govern nuclear materials, guide research, regulate production, and oversee closure, clean-up, and monitoring of nuclear-affected sites. While agencies such as the Nuclear Regulatory Commission and the Environmental Protection Agency have helped to make existing nuclear sites safer, their efforts were compartmentalized in ways that mirrored the Manhattan Project itself. Narrowly defined jurisdictions, missions, goals, and outcomes make it difficult to address holistically the political, environmental, and ethical questions raised by the use of nuclear materials. Beyond the purview of government (and with neither its funding nor its power), community groups have employed a wide range of strategies to insert friction into the smooth operation of the nuclear complex, including citizen science, irony and humor, visual and performance interventions, and direct action protest. Finally, nuclear materials exhibit their own agency with a persistence that has frustrated countless efforts to harness and contain them for military and industrial purposes.