This post is not about a nuclear leak, rather a radioactive materials accident that took place in 1987. The blog The Last Word On Nothing recently summarized a famous incident in Goiânia, Brazil in which the locals were exposed to cesium chloride. It is considered one of the worst radioactive disasters ever and occurred after radiotherapy materials were scavenged from an abandoned hospital site. According to Wiki, "The dispersal of radiation was equivalent to a medium-size dirty bomb."
From The Last Word On Nothing:
On 13 September , the men brought a wheelbarrow to the dilapidated building, took apart the heavy outer assembly, and transported the inner canister back to Leide’s uncle’s scrap lot, where they got about $25 for it. When Devair Ferreira’s employees smashed the canister open, they found still another inner container. Ernesto, one of the employees, finally pried the capsule open with a screwdriver.
His curiosity was rewarded with about a third of an ounce of sparkling, glowing blue powder. The consistency was variable—some crystals were as big as rice grains; others the size of dust. They were held loosely together in a crumbly cake, which Ernesto broke apart and sifted through his fingers. Witnesses later said they remembered him calling it “carnival glitter.” Ernesto chose one of the bigger blue crystals to make into a ring for his wife, put it in his right front pocket, and went back to work.
The powder enthralled everyone. Devair began to suspect that it might be supernatural. His brother dipped a finger into the dust and drew a cross on his abdomen. Maria slept in bedclothes covered in the sparkly blue dust. Neighbors and acquaintances came to the Ferreiras’ home to take some of the mystical powder for good luck. ... The blue glitter wasn’t magical, but it did have some powerful properties: the salt, called cesium chloride, was used in the radiotherapy machine. As its active ingredient, cesium-137, decays, it emits two radioactive products: beta particles and gamma rays.
Read the rest of the account of this incident here. The Wiki page on the accident is here. There is a list of civilian radioactive accidents here; these often relate to mishandling of radioactive materials in medical situations. This is the less-discussed side to radioactive contamination, beyond bombs, tests, subs and nuclear plants. (Thanks to J. for the link.)