An 18-year mortality analysis reveals elevated cancer death rates in U.S. counties positioned closer to operational nuclear facilities, with the effect most pronounced among older demographics—males 65-74 and females 55-64. The pattern persists after controlling for socioeconomic status, healthcare access, and environmental confounders. This epidemiological signal challenges long-standing regulatory assumptions about radiation exposure limits around nuclear installations. The association could reflect low-level chronic exposure to radioactive emissions, occupational risks among plant workers and their families, or unmeasured environmental factors correlated with plant siting decisions. However, the observational design cannot establish direct causation, and the study lacks data on individual exposure histories or cancer subtypes that might show stronger radiation signatures. The findings arrive as policymakers promote nuclear expansion for climate goals, creating tension between decarbonization strategies and potential public health trade-offs. While previous studies have yielded mixed results on nuclear proximity and health outcomes, this comprehensive national analysis suggests the relationship deserves more rigorous investigation, particularly given that millions of Americans live within 50 miles of nuclear facilities.