A single gram of Polonium-210 is lethal enough to kill 50 million people.

Polonium-210 is a rare and highly radioactive metalloid first discovered by Marie and Pierre Curie in 1898. It is found naturally in uranium ores but is primarily produced today in nuclear reactors by bombarding Bismuth-209 with neutrons. This isotope has a relatively short half-life of 138 days, which means it releases a massive amount of energy in a very short period through alpha decay.The toxicity of Polonium-210 is purely radiological rather than chemical. When ingested, the alpha particles it emits have high linear energy transfer, meaning they dump all their energy into a small volume of tissue. This process causes catastrophic double-strand breaks in DNA and leads to a condition known as Acute Radiation Syndrome. Unlike beta or gamma radiation, alpha particles are easily stopped by a sheet of paper, but they are devastating once they enter the bloodstream.One of the most famous cases of Polonium-210 poisoning occurred in London in 2006. Former Russian intelligence officer Alexander Litvinenko died after consuming tea laced with a microscopic amount of the substance. Forensic experts from the Health Protection Agency estimated that his dose was only a few micrograms, yet it caused total organ failure in just three weeks. This event highlighted how difficult the substance is to detect, as it does not trigger standard Geiger counters which are designed for gamma radiation.