Abstrac: The failure of experts and lay people to understand each other has been fueling conflict around the environmental clean-up of the many sites in the United States that are contaminated by the nuclear weapons program. This mutual distrust was exacerbated by the culture of secrecy surrounding the atomic weapons program during World War II, and later by the innate culture of bureaucracy in the federal agencies that have sprung up since then. A prime example of this problem can be found in the regulation of chronic long-term risk from low-level radiation exposure affecting communities in Missouri’s North St. Louis County. This case study illuminates this divide, and illustrates opportunities to close it.