9. Radioactive Waste Vaults
During the Cold War, several cities carved sealed concrete vaults beneath remote municipal sites to store low-level nuclear waste generated by hospitals, research labs, and industry. Los Angeles housed barrelled radioisotopes under a grassy knoll at its municipal airport, while Seattle and Portland placed vaults beneath depots on the city’s outskirts.
By the 1980s, federal regulations required decommissioning and secure closure of these underground chambers. Today they remain buried and monitored as legacies of early nuclear-age practices. Learn more from NRC Low-Level Waste Disposal.
