A cancer drug just passed its Phase 3 trial, and the active ingredient comes from Cold War nuclear bomb material the US government was paying to destroy. The drug is actinium-225 attached to a peptide that hunts down a receptor on neuroendocrine tumor cells. Once it docks, the actinium fires off alpha particles that travel only 2 to 3 cell widths before stopping. The tumor cell dies. The healthy cell next door barely notices. The science was the easy part. Actinium-225 is one of the rarest usable substances on earth. For decades, nearly the entire global supply came from a single thorium-229 sample at Oak Ridge National Laboratory, milked about 8 times a year, yielding roughly 1.2 curies annually. Enough for clinical trials and not much else. That was the whole planet's supply. Thorium-229 decays out of uranium-233, material the US produced for its nuclear weapons program. The Department of Energy classified that stockpile as waste and has spent years paying contractors to dispose of it. Then someone realized the waste contained the parent isotope of the best cancer-killing atom we've ever found. Bill Gates's TerraPower now partners with the DOE contractor to pull thorium-229 out of the uranium before it gets destroyed. They've extracted over 15 grams so far. Before this project, about 1 gram existed outside Oak Ridge in the entire world. At full scale, that one recovery effort yields around 90 curies of actinium-225 per year, enough to make 100x more doses than humanity could produce before. Bristol Myers Squibb paid $4.1 billion for RayzeBio, the startup behind this drug, before the Phase 3 even read out. They built a plant in Indianapolis that ships every dose within 3 days of production, because actinium-225 has a 10-day half-life. The medicine decays while it travels. The best cancer-killing atom we know of spent 60 years sitting in a Tennessee stockpile marked for disposal.