Goiânia accident: A radioactive object is stolen from an abandoned hospital in Goiânia, Brazil, contaminating many people in the following weeks and causing some to die from radiation poisoning.

The Goiânia accident ), also known locally as the caesium-137 accident/caesium-137 Goiânia, was a radioactive contamination accident that occurred on September 13, 1987, in Goiânia, Goiás, Brazil, after an unsecured radiotherapy source, inside a lead-and-steel medical device, was found by scavenger thieves at an abandoned hospital site in the city. The thieves, and then workers at the scrapyard owned by Devair Ferreira, who bought the device from the thieves, used tools to open the device and expose the caesium-137 crystals. Ferreira brought the exposed caesium-137 crystals to his home, sharing them with his family and neighbours; the caesium-137 crystals were subsequently handled by many people, resulting in four deaths – two of Ferreira's family members and two of his scrapyard employees. About 112,000 people were examined for radioactive contamination and 249 of them were found to have been contaminated.