The Goiânia Accident Explained: The Glowing Powder That Poisoned An Entire City
The Radioactive Powder People Took Home And Gave To Their Families
Inside One Of History’s Strangest Nuclear Accidents
In September 1987, two men entered an abandoned medical clinic in Goiânia, Brazil, looking for equipment they could sell as scrap. What they eventually carried away in a wheelbarrow looked like valuable machinery. Hidden inside it was a highly radioactive source containing cesium-137.
Within days, the source had been broken open. A strange blue glow appeared inside the capsule. People gathered around it, touched the material, carried fragments home and even rubbed the radioactive powder onto their skin because they thought it was beautiful. By the time anyone understood what was happening, radioactive contamination had travelled through houses, scrapyards, public transport and neighbourhoods across Goiânia.
The phrase that the powder "poisoned an entire city" should not be taken literally: most of Goiânia's population was never significantly contaminated. But the accident became a city-wide emergency. More than 112,000 people were eventually screened, hundreds required decontamination, 249 were identified as significantly contaminated and four people died directly from the radiation exposure.
Almost four decades later, Goiânia remains one of the most important radiological accidents ever studied. It was not caused by a reactor explosion, a nuclear weapon or a secret military programme. It began with something far more mundane: a dangerous medical source was left where ordinary people could reach it.
The Machine Left Behind
The origin of the disaster was the Instituto Goiano de Radioterapia, a private radiotherapy clinic that had moved from its former premises. A teletherapy machine remained inside the abandoned building.
Machines of this kind once used powerful radioactive sources to deliver radiation to cancerous tissue. When operating properly, the source was shielded inside heavy equipment and carefully controlled. Outside that protection, however, the radioactive material could deliver an extremely dangerous dose.
The source in Goiânia contained cesium-137 chloride and had an activity of approximately 50.9 terabecquerels, or 1,375 curies. That was not a trivial laboratory sample. It was a powerful radiotherapy source designed precisely because it could emit intense radiation.
Cesium-137 is produced through nuclear fission. It emits beta and gamma radiation and has a half-life of about 30 years. Cesium chloride is particularly problematic when a source is breached because it is soluble and can break into fine material capable of spreading across surfaces, clothing and the human body.
The danger was invisible.
There was no smoke cloud hanging over the building. There was no explosion to announce that something catastrophic had occurred. The men dismantling the machine had no reliable way of sensing that they were standing beside a potentially lethal radiation source.
Between 10 and 13 September 1987, they worked on the equipment using simple tools. Eventually they removed part of the rotating assembly containing the radioactive source and transported roughly 200 kilograms of machinery away from the clinic in a wheelbarrow.
Almost immediately, their bodies began giving them warnings that they did not understand.
The First Symptoms Appeared Almost Immediately
By 13 September, both men were vomiting.
The following day, one suffered diarrhoea and dizziness. His hand became swollen. He later developed a radiation injury consistent with the position in which he had been holding part of the machine.
Yet radiation sickness was hardly the obvious explanation.
One of the men sought medical assistance on 15 September. His symptoms were attributed to something resembling an allergic reaction caused by bad food, and he returned home. In isolation, nausea, diarrhoea and vomiting looked far more like ordinary illness or food poisoning than the opening phase of a radiological disaster.
Meanwhile, the source remained uncontrolled.
One of the men continued attempting to dismantle it beneath a mango tree at his home. A screwdriver punctured the approximately one-millimetre-thick window of the source capsule, allowing some of the material inside to be removed. At one stage he apparently thought the substance might be gunpowder and tried to ignite it.
The house and surrounding ground became heavily contaminated. Radiation measurements later taken beneath the mango tree were extraordinarily high, and the property eventually had to be demolished while contaminated topsoil was removed.
But the disaster was about to become far worse.
On 18 September, pieces of the dismantled equipment were sold to a scrapyard.
That was where someone noticed the glow.
The Blue Glow That Changed Everything
That evening, the scrapyard owner entered the garage where the machinery had been placed and saw an unusual blue light coming from the source capsule.
It fascinated him.
He reportedly believed the substance might be valuable, perhaps resembling a gemstone, or even something supernatural. Instead of recognising it as a warning, the glow made the object more desirable. The capsule was brought inside the house and shown to other people.
Neighbours, relatives and acquaintances came to look.
Fragments roughly the size of grains of rice were removed from the source. The material could crumble into powder. Pieces were distributed among family members and acquaintances, while some people placed the glowing material directly onto their skin in a way compared in the official investigation with carnival glitter.
This is what makes Goiânia so disturbing.
Radiation itself normally gives the human senses almost nothing to work with. You cannot reliably smell, taste or feel ionising radiation. Yet here the breached source produced an unusual visual phenomenon that encouraged people to approach it.
The official investigation later concluded that interest generated by the blue glow significantly affected the course of the accident. Investigators noted that a similar phenomenon was reproduced when another cesium-137 chloride source was opened under controlled conditions in the United States in 1988. Possible explanations included fluorescence or Cherenkov radiation associated with moisture absorbed by the material.
The haunting irony is difficult to miss.
The one visible feature associated with the radioactive substance did not look threatening.
It looked beautiful.
Radioactive Material Entered Ordinary Homes
The source was no longer confined to one building or scrapyard.
People carried pieces away.
Contamination travelled with them on their hands, clothing and possessions. Family homes became radioactive environments. Material reached different scrapyards. Individuals moved through the city without knowing they were carrying cesium-137.
Cesium chloride's physical properties made the situation particularly dangerous. Unlike a radioactive object that remained solid and intact, the material from the ruptured source could fragment and disperse. Its high solubility made internal contamination possible when particles were swallowed, inhaled or entered damaged skin.
Once cesium enters the body, the problem becomes different from simply standing close to a radioactive source. Contaminated material inside the body can continue irradiating tissue until it is eliminated, removed through treatment or decays.
The people affected did not understand any of this.
They were living with what appeared to be an unexplained outbreak of sickness.
People developed nausea, vomiting, diarrhoea, dizziness and radiation injuries resembling burns. Some went to hospitals. Others remained around contaminated relatives and houses because neither patients nor medical staff initially knew that radiation was involved.
One family member who nursed an ill relative subsequently carried substantial contamination away from the original area.
Every ordinary movement created another potential pathway.
A visit to someone's home.
A bus journey.
A piece of material given to a relative.
Contaminated clothing.
A meal eaten after touching radioactive powder.
Goiânia was turning into a radiological emergency without anybody realising that a radiological emergency existed.
The Six-Year-Old Girl Who Became The Symbol Of Goiânia
Among the victims was six-year-old Leide das Neves Ferreira.
She became the most recognised individual victim of the disaster and eventually gave her name to institutions established to care for people affected by the accident.
Leide came into contact with cesium-137 within her family's environment. She played with the substance and ingested radioactive material after eating with contaminated hands. Her exposure was devastating.
She died on 23 October 1987.
Leide's case captures what numbers alone cannot.
This was not a disaster involving trained nuclear technicians who knowingly entered a dangerous environment. Many of those exposed were ordinary families who did not know that a strange glowing substance carried a lethal hazard.
There was no reasonable way for a six-year-old child to understand what cesium-137 was.
That responsibility belonged elsewhere.
The Woman Who Realised Something Was Wrong
The chain of contamination might have continued for longer if Maria Gabriela Ferreira, the wife of the scrapyard owner, had not become suspicious.
People around the object were becoming ill.
She began to connect their sickness with the mysterious piece of equipment.
Maria Gabriela eventually took the remains of the source to the local health authorities. In doing so she helped trigger the discovery of what had really been happening. The accident was recognised on 28 September, with its full seriousness becoming apparent on 29 September.
Physicist Walter Mendes Ferreira was among the people central to technically identifying the radioactive contamination.
Once radiation monitoring equipment was brought in, the mystery ceased to be mysterious.
The readings made clear that Goiânia was facing an extraordinary radiological accident.
Maria Gabriela would not survive it.
She died on 23 October, the same day as Leide. Two young scrapyard workers, Israel Batista dos Santos and Admilson Alves de Souza, died several days later.
Four people were now dead because a source designed to treat disease had escaped the system responsible for controlling it.
A City Suddenly Feared Radiation Everywhere
Once authorities understood what had happened, the problem changed almost instantly.
Until then, the greatest danger had been ignorance.
Now it was panic.
Police, firefighters and civil-defence personnel were mobilised. Contaminated areas were isolated. Residents around major sites were evacuated, while the Olympic stadium in Goiânia became a mass screening centre.
Rumours spread.
People woke to cordoned streets without fully understanding why neighbourhoods were being sealed off. Large numbers headed towards the stadium wanting to know whether they and their families were radioactive.
More than 112,000 people were ultimately examined according to contemporary official figures, although later technical documents use slightly different totals because of differences in screening and classification. Goiás authorities record 112,800 people monitored, with 249 found to have significant internal or external contamination.
Of those 249, contamination in 120 cases was confined to clothing and footwear and could be dealt with through decontamination. Another 129 required continuing medical follow-up.
Twenty patients were initially sent to Goiânia General Hospital. Fourteen of the most severely affected were later transferred to specialist treatment in Rio de Janeiro.
Eight developed acute radiation syndrome. Fourteen experienced bone-marrow failure. Twenty-eight suffered radiation-related skin injuries to varying degrees. One patient required amputation of part of an arm.
Four died approximately four to five weeks after exposure, with haemorrhage and severe infection among the complications associated with acute radiation syndrome.
The numbers were far smaller than the terrified population initially feared.
Psychologically, however, the entire city had been changed.
How Radiation Was Removed From The Victims
Treating the victims presented an unusual problem because patients were not merely suffering from previous exposure.
Some were themselves contaminated.
Cesium-137 remained on skin or inside their bodies. Sweat could carry contamination from internally contaminated patients back onto external surfaces, complicating nursing and isolation procedures.
Doctors therefore needed both to treat radiation injuries and to reduce the amount of radioactive cesium remaining in the body.
Decontamination methods included washing with warm water and neutral soap, chemical techniques intended to make material easier to remove, specialised substances applied to heavily contaminated areas such as the hands and feet, and in some circumstances abrasive cleaning methods.
One of the most important treatments was Prussian blue.
The compound can bind radioactive cesium inside the gastrointestinal tract, reducing its reabsorption and accelerating its elimination from the body. The Goiânia response became a historically significant example of its use following substantial internal cesium contamination.
Radiation damage, however, cannot simply be washed away once sufficient energy has already been absorbed by tissue.
For the most seriously exposed patients, doctors were dealing with damage to bone marrow, skin and other biological systems while attempting to prevent infection and haemorrhage.
Treatment could reduce further contamination.
It could not undo every dose already received.
Entire Houses Had To Be Destroyed
Stopping the medical emergency was only part of the problem.
Goiânia itself had to be cleaned.
Investigators identified seven principal contamination sites. Teams traced movements, possessions and relationships between people in an attempt to reconstruct where pieces of the source had travelled.
Buildings were surveyed.
Contaminated objects were removed.
Some houses could not simply be cleaned and returned to their owners. Structures were demolished. Soil was excavated. Personal possessions became radioactive waste.
The resulting volume was enormous relative to the tiny source that had started everything.
Around 3,500 cubic metres of radioactive waste were ultimately produced by the cleanup, stored in specially designed containers. A disposal site was established outside Goiânia, in what became the permanent waste facility at Abadia de Goiás.
This remains one of the most striking lessons of radioactive contamination.
The original cesium source was physically small.
Its consequences were not.
Once radioactive material had been pulverised, moved through homes and transferred onto ordinary possessions, the boundaries of the source effectively disappeared. A contaminated chair, floor, wall, piece of clothing or patch of earth could itself become part of the problem.
A small quantity of material created thousands of cubic metres of waste.
Why Goiânia Was Not A Nuclear Accident Like Chernobyl
Goiânia is sometimes discussed alongside Chernobyl or Fukushima, but the mechanism was fundamentally different.
There was no nuclear reactor.
There was no nuclear chain reaction running out of control.
There was no explosion releasing reactor material across a vast region.
Goiânia was a radiological accident involving what is sometimes described as an orphan source: radioactive material that had effectively escaped appropriate regulatory and physical control.
That distinction matters because radioactive sources exist far beyond nuclear power stations.
They have been used in medicine, industry, construction, research, sterilisation and measurement. A sufficiently powerful source does not need to be inside a reactor to become dangerous.
The Goiânia source had originally served a beneficial medical purpose.
The catastrophe began when the system around that source failed.
Who Was Responsible?
The two men who dismantled the machine physically released the source, but treating them as the sole cause misses the central lesson of the disaster.
They did not knowingly steal an exposed container of cesium-137.
They encountered abandoned equipment and believed it had scrap value.
The far larger question was why an intensely radioactive medical source had remained accessible inside abandoned premises in the first place.
The accident exposed weaknesses involving ownership, licensing, security, communication and responsibility for radioactive equipment once a medical facility changed location.
The official international review subsequently emphasised the importance of systems capable of accounting for radioactive sources throughout their entire working lives. Regulators need to know not merely where radioactive material was originally licensed, but whether it remains where records say it should be.
Public understanding matters too.
The radiation symbol is useful only if the person looking at it knows what it means.
Investigators noted that radioactive sources require markings recognisable to the wider public. The strange blue glow in Goiânia attracted people towards the source; an unmistakable warning needed to do the opposite.
The Disaster Did Not End In 1987
The immediate emergency eventually came under control, but Goiânia did not simply return to the day before the accident.
Survivors required continued medical surveillance.
The Goiás government established the Fundação Leide das Neves Ferreira in 1988 to support people affected by the accident and monitor possible consequences of radiation exposure. Its responsibilities were later inherited by institutions that continue working with radioaccident victims.
That legacy remains active.
The Centro Estadual de Assistência aos Radioacidentados Leide das Neves continues to provide multidisciplinary monitoring and healthcare for people affected by the accident. Goiás also maintains a dedicated information system for monitoring radioaccident victims.
In June 2026, Brazil's nuclear authorities again revisited the disaster when Walter Mendes Ferreira, the physicist involved in identifying the contamination, spoke publicly about the events of 1987. Nearly four decades after the accident, Goiânia continues to be treated not simply as history but as a case study in what happens when radioactive material becomes disconnected from the system designed to control it.
The Most Frightening Lesson From Goiânia
The Goiânia accident killed four people directly, severely injured others and forced an enormous public-health and decontamination operation.
But the reason it remains so unsettling is not its death toll.
It is how ordinary everything looked before the danger was understood.
There was an abandoned building.
A piece of scrap metal.
A wheelbarrow.
A scrapyard.
Families visiting one another.
A child eating at home.
And in the middle of it all was a substance emitting radiation powerful enough to destroy human tissue while giving almost no warning that anything was wrong.
Even the one extraordinary clue seemed inviting.
It glowed blue.
That glow helped turn a dangerous industrial object into a curiosity. People moved towards it when survival required them to move away. The physical properties of cesium chloride then did the rest, allowing contamination to spread through a network of normal human behaviour.
Goiânia therefore represents something different from the familiar image of nuclear catastrophe.
There was no mushroom cloud and no destroyed reactor.
Instead, a powerful radioactive source quietly left institutional control and entered everyday life.
That may be the most important lesson of all. Catastrophic technology does not always become dangerous because the technology itself suddenly fails. Sometimes the machinery works exactly as physics says it will.
The failure is losing track of it.
And in Goiânia, by the time people discovered what the beautiful blue powder really was, it had already passed from a medical machine into a scrapyard, from the scrapyard into homes, and from those homes into the lives of an entire city.
