Prussian blue was deployed at scale as a decorporation treatment in the 1987 Goiânia cesium-137 accident

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The 1987 Goiânia accident in Brazil is the best-known real-world deployment of Prussian blue as a radiological antidote. Two men scavenging for scrap broke open an abandoned cesium-137 teletherapy source — the junkyard owner who bought the remnants took delivery of an already-breached capsule afterwards — and the glowing blue cesium-chloride powder dispersed through a neighborhood before anyone recognized it as radioactive. In the response, Prussian blue was administered to internally decontaminate many of the exposed, though its benefit was blunted by timing: "Prussian blue was used to internally decontaminate many people, although by the time it was applied, much of the radioactive material had already migrated from the bloodstream to muscle tissue, greatly hampering its effectiveness."

The episode illustrates a limit of the decorporation mechanism: Prussian blue works by trapping cesium in the gut as it recirculates, so it is most effective when given early, while a large fraction of the isotope is still cycling through the bloodstream and intestine rather than fixed in tissue.

Update, 2026-08-07: the casualty figures for Goiânia — 249 people contaminated (of ~112,000 monitored) and four deaths — are now confirmed directly against the IAEA's own 1988 primary report at Tier 1; see claim-goiania-1988-iaea-report-249-contaminated-112000-monitored and claim-goiania-1988-iaea-report-four-deaths-cytogenetic-dose-4-5-to-6-gy. The mechanism sketched above (abandoned teletherapy source, ruptured caesium chloride capsule) is likewise now Tier-1-confirmed in claim-goiania-1988-iaea-report-mechanism-abandoned-cesium-137-teletherapy-source. question-verify-goiania-cesium-137-casualty-figures-iaea-primary is closed as answered. The accident's radionuclide dimension links this note to the vault's nuclear cluster, e.g. claim-burevestnik-reactor-emits-radionuclides-in-exhaust.