On 24 September, 1987, six year old Leide Ferreira threw up ten minutes after eating her egg sandwich. The next day her parents started throwing up too. Vomiting and diarrhea were followed by strange aches and burns. When Leide’s mother Maria went to the public health clinic in Goiás, the doctor ascribed her symptoms to food poisoning and sent her back home. Leide’s grandmother, who came to help her family, got sick too. Lesions crept over their skin and their hair fell out. The family’s neighbors began to think they had AIDS.

On 28 September, Maria dragged herself back to the doctor’s office and deposited on his desk a small plastic bag filled with iridescent blue powder. This, she said, was the culprit. The doctor dismissed her claims as superstitious nonsense and admitted her to the Tropical Diseases hospital. But another doctor at the clinic called a health physicist to test the mysterious bag. The next day, 112 thousand people found themselves packed into Olympic stadium, queuing at hastily constructed tents to be tested for radiation poisoning.

Goiânia is the capital of the state of Goiás in central Brazil. About 1.3 million people live there. In 1971, a local cancer treatment clinic bought a radiation therapy machine. When the practice closed 14 years later, the administrators left the now-obsolete machine in the abandoned clinic without notifying either the state or Brazil’s National Nuclear Energy Commission (CNEN).

The deserted clinic went through the usual process of decomposition. By 1987, the building had been reduced to three ramshackle walls with large holes eating through the peeling sides. Homeless people slept there. The erstwhile treatment room contained human excrement and the still relatively intact radiological machine, which looks like a cross between an enormous telescope and a dentist’s chair.

That machine was finally discovered by Roberto dos Santos Alves and Wagner Mota Pereira, two locals who made their living selling scrap metal. 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. Six-year-old Leide rubbed the powder all over her arms so that she glowed and sparkled. The bedclothes, the house, and the girl were covered in crystals. So was the egg sandwich she ate for lunch.

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, both of which damage the body. Beta particles are simply electrons. They travel slowly and without much force. At worst, external exposure irritates the skin, causing a sunburn-like reddening called “beta burn,” but skin cells are tough enough to easily block beta particles from doing any internal damage. But when they’re ingested, the story changes. The same sluggish travel capacity that makes them relatively harmless outside the body makes them more harmful inside, where all their energy is trapped inside a tiny radius. The more energy the electron burns into each cell, the worse the damage, and the more DNA strands are broken.

The other product of cesium-137 decay is gamma radiation. Gamma rays are photons, just like visible light, but with about 10,000 times as much energy. Gamma rays are more penetrating than beta particles, in fact more so than x-rays: they barely notice the skin as they glide through organs, muscle, and bone. Because they are so deeply penetrating, they may not hit any cells at all, but just pass through the body without interaction. Whether they hit a cell or pass through depends on how much radiation is emitted by the source and how close a person is to that source. The corollary of “beta burn” is called a thermal gamma burn, but instead of irritating the skin, it fries the organs inside the body.

The larger particles Leide had rubbed on her skin adhered to the sandwich and wreaked havoc on her stomach and intestine cells during digestion. The finest crystals clung to the dust she breathed and drifted into her lungs.

The time it takes to die of radiation poisoning depends on how the exposure compares to background radiation, the nominal amount of radiation a person can expect to receive from the natural environment. That’s around 0.002 Gray per hour, a Gray being the standard international unit of absorbed radiation dose. If gamma radiation can be thought of as a steady stream of progressively more lethal bullets, the Gray measures how many of those little bullets will hit during a given amount of time. A dose of 4-5 Grays—30,000 times the background levels—kills all the body’s red and white blood cells. The death of these cells destroys the immune system, and opportunistic diseases can roam free. The exposed individual dies within a few weeks.

Once CNEN realized the magnitude of the contamination, the organization cast a wide net to test as many people as they could. They flew 54 severely contaminated people to a hospital in Rio de Janeiro, where they were put in “reverse isolation,” which, instead of protecting the staff from a patient’s infection, protects patients with compromised immune systems from infections caused by something as innocuous as a fungus or a common cold carried by a nurse’s aide. Hospital staff had to decontaminate patients’ skin anew every day, using a mix of soapy water and a diluted acid, because their sweat kept re-contaminating their own skin from the inside.

The first task, however, was to remove as much of the internal source as they could. “When you’re internally exposed, the first thing you want to do is just get it out of your body by any means necessary,” says Jonathan Links, a health physicist at Johns Hopkins University and the former president of the Nuclear Medicine Society. “You start with brute force: lavage, laxatives. Just get whatever is inside out.” In addition to the “brute force” tactics, they tried chemical methods. Prussian Blue is a chemical agent that works by bonding to the radioactive particles inside the body. These are then secreted through the normal pathways: urine, feces, and sweat.

Most of the 54 survived because they were exposed to less than 1 Gray. However, several people lost fingers, and 23 people were treated for localized radiation burns. Five required skin grafts. Ernesto, the scrap yard worker who had sifted lovingly through the entire cake of fairy dust, received intense thermal gamma burns on his hands and on his right thigh, where the cesium-137 chunk intended for his wife’s ring had burned through his trousers.

The men who had dismantled the cancer therapy machine in the clinic fared badly. According to the IAEA report detailing the incident [PDF], Pereira and Alves had probably been exposed to doses around 4 Gray from the moment they moved the giant machine. Both men had complained of vomiting, diarrhea and vertigo within days of their initial exposure, and Pereira’s hand was swollen and burned. Like Leide’s father, he had been initially diagnosed with a reaction to tainted food. Late in October, two of Devair’s other workers died of internal hemorrhaging.

For Leide and her mother, the only care the hospital could offer was palliative. Leide had an estimated internal dose of 4 Gray—that’s just from inhalation and ingestion—and she died on 23 October, on the same day as her mother. She was buried in a lead coffin, sealed with concrete.

Leide’s death was only the first tremor of what would happen in Goiânia. Less than half an ounce of cesium chloride would become a city-wide contamination, a political and economic catastrophe, and 13 and a half tons of nuclear waste. And that was just in the first month.

Last week, the New York Times reported that the reactors at the Fukushima Daiichi plant reactors have discharged mainly iodine-131 and cesium-137. “It’s the cesium that would prompt an evacuation,” Argonne National Laboratory nuclear engineer Shih-Yew Chen told Science, which also reported that Japan’s cesium-137 soil measurements are now surprisingly high.

What makes the Goiânia incident instructive is that unlike the Chernobyl disaster, which spewed everything—strontium, cesium, iodine and a whole assortment of nasty characters—here the sole contaminant was cesium-137. It has been possible to trace the effects, over 30 years, of a single source of a single radioactive isotope.

I’ll continue the story next time.

[The opening picture: It’s not cesium chloride. It’s art courtesy of flickr user bmooneyatwork. The map is courtesy of the 1988 International Atomic Energy Agency report on the incident. The third image shows people being tested for exposure at the stadium, courtesy of CNEN, and you can find it in the IAEA report. The fourth image is actual cesium, but not cesium chloride, by Wikimedia user Dennis “S.K.”]