The Goiânia accident (Brazilian Portuguese: [ɡo(j)ˈjɐniɐ]), 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 (specifically a caesium chloride salt). 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.
In the consequent cleanup operation, topsoil had to be removed from several sites, and several houses were demolished. All the objects from within those houses, including personal possessions, were seized and incinerated. Time magazine has identified the accident as one of the world's "worst nuclear disasters" and the International Atomic Energy Agency (IAEA) called it "one of the world's worst radiological incidents".
The radiation source in the Goiânia accident was a small capsule containing about 93 grams (3.3 oz) of highly radioactive caesium chloride (a caesium salt) made with the radioactive isotope caesium-137, and encased in a shielding canister made of lead and steel. The source was positioned in a container of the wheel type, where the wheel turns inside the casing to move the source between the storage and irradiation positions.
The activity of the source was 74 terabecquerels (2,000 Ci) in 1971. The International Atomic Energy Agency (IAEA) describes the container as an "international standard capsule". It was 51 mm (2.0 in) in diameter and 48 mm (1.9 in) long. The specific activity of the active solid was about 814 TBq/kg (9,980 Ci/lb) of caesium-137, an isotope whose half life is 30 years. The dose rate at one meter from the source was 4.56 grays (456 rad) per hour – enough to receive the median lethal dose of 4 Gy (400 rad) in less than an hour. While the serial number of the device was unknown, hindering the ability to verify its identity, the device was thought to have been made in the U.S. at Oak Ridge National Laboratory as a radiation source for radiation therapy at the Goiânia hospital.
The IAEA states that the source contained 50.9 TBq (1,375 Ci) when it was taken and that about 44 TBq (1,200 Ci) of contamination had been recovered during the cleanup operation. This means that 7 TBq (190 Ci) remained in the environment; it would have decayed to about 3.5 TBq (95 Ci) by 2016.
The Instituto Goiano de Radioterapia (IGR), a private radiotherapy institute in Goiânia, was one kilometre (0.6 mi) northwest of Praça Cívica, the administrative center of the city. In 1985, IGR moved to new premises, but left behind a caesium-137-based radiotherapy unit purchased in 1977. In 1986, the fate of the abandoned site was disputed in the Court of Goiás between IGR and the Society of Saint Vincent de Paul, then owner of the premises. On September 11, 1986, during those court hearings, the Court of Goiás was informed of the abandoned radioactive material in the building.
Four months before the theft, on May 4, 1987, Saura Taniguti, then director of the Social Security Institute for Civil Servants in the State of Goiás Instituto de Previdência e Assistência do Estado de Goiás (IPASGO), called the police to prevent one of the owners of IGR, Carlos Figueiredo Bezerril, from removing various items that had been left behind. IPASGO owned the land the abandoned facility stood on, and Figueiredo then warned the president of IPASGO, Lício Teixeira Borges, that the radioactive material was at the site, and that IPASGO would now be responsible "for what would happen with the cesium bomb". The Court of Goiás posted a security guard to protect the site. Meanwhile, the owners of IGR had written several letters to Brazil's National Nuclear Energy Commission (Comissão Nacional de Energia Nuclear; CNEN), warning them about the danger of keeping a teletherapy unit at an abandoned site, and stating IGR could not remove the equipment as a court order prevented them from doing so.
On September 13, 1987, the guard tasked with protecting the site did not show up for work. Roberto dos Santos Alves and Wagner Mota Pereira illegally entered the partially demolished and crumbling IGR site. They partially disassembled the teletherapy unit and placed the source assembly in a wheelbarrow to later take to Roberto's home. They thought they might get some scrap value for the unit. They began dismantling the equipment. That same evening, they both began to vomit due to radiation sickness. The following day, Pereira began to experience diarrhea and dizziness, and his left hand began to swell. On September 15, Pereira visited a local clinic, where he was diagnosed with a foodborne illness; he was told to return home and rest. He later developed a burn on his hand in the same size and shape as the aperture, and he underwent partial amputation of several fingers. Roberto, however, continued with his efforts to dismantle the equipment and eventually freed the cesium capsule from its protective rotating head. His prolonged exposure to the radioactive material led to his right forearm becoming ulcerated, requiring amputation on October 14.
On September 16, Roberto punctured the cesium capsule's aperture window with a screwdriver, allowing him to see a deep blue light coming from the tiny opening he had created. He inserted the screwdriver and successfully scooped out some of the glowing substance. Thinking it was perhaps a type of gunpowder, he tried to light it, but the powder would not ignite.
The exact mechanism by which the blue light was generated was not known at the time the IAEA report of the incident was written, though it was thought to be either ionized air glow, fluorescence, or Cherenkov radiation associated with the absorption of moisture by the source; a similar blue light was observed in 1988 at Oak Ridge National Laboratory in the United States during the disencapsulation of a caesium-137 source.
On September 18, Roberto sold the items to a nearby scrapyard. That night, Devair Alves Ferreira, the owner of the scrapyard, noticed the blue glow from the punctured capsule. Thinking the capsule's contents were valuable or supernatural, he immediately brought it into his house. Over the next three days, he invited friends and family to view the strange glowing powder.
On September 21, at the scrapyard, one of Ferreira's friends (identified as "EF1" in the IAEA report) freed several rice-sized grains of the glowing material from the capsule using a screwdriver. Ferreira began to share some of them with various friends and family members. That same day, his wife, 37-year-old Maria Gabriela Ferreira, began to fall ill. On September 25, 1987, Devair Ferreira sold the scrap metal to a third scrapyard.
The day before the sale to the third scrapyard, on September 24, Ivo, Devair's brother, successfully scraped some additional dust out of the source and took it to his house a short distance away. He spread some of it on the concrete floor. His six-year-old daughter, Leide das Neves Ferreira, later ate an egg while sitting on the floor. She was also fascinated by the powder's blue glow, applying it to her body and showing it off to her mother. The egg was also exposed to dust from the powder; Leide absorbed 1.0 GBq (27 mCi) and received a total dose of 6.0 Gy (600 rad), a fatal dose for which medical intervention was ineffective. Leide's mother, Lurdes Ferreira, also got sick from the radiation.
Maria Gabriela Ferreira had been the first to notice that many people around her had become severely ill at the same time. On September 28, 1987 – fifteen days after the item was found – she reclaimed the materials from the rival scrapyard and transported them to a hospital.