In This Guide
The Goiânia Radiological Accident with Cesium-137
In September 1987, two scrap metal collectors dismantled an abandoned teletherapy unit at a decommissioned clinic in downtown Goiânia, the capital of Goiás state in central Brazil, and ruptured a capsule containing 50.9 TBq (1,375 Ci) of cesium-137 chloride. The glowing blue powder captivated family members and neighbors — and spread radioactive contamination across multiple neighborhoods over two weeks. Four people died. Dozens were irradiated. Entire blocks had to be evacuated and houses demolished. The International Atomic Energy Agency (IAEA) classified the event as one of the most serious radiological accidents ever recorded.
“The Radiological Accident in Goiânia,” published by the IAEA in September 1988 (STI/PUB/815), was produced jointly with Brazil’s National Nuclear Energy Commission (CNEN) after an international review meeting. Experts designated by the Brazilian government and other member states examined the causes, consequences, and management of the accident. The resulting report covers everything from the technical description of the teletherapy unit and source to the autopsies of those who died, including dosimetry, environmental decontamination, and recommendations to prevent similar events.
Goiânia was more than a tragedy. It was the first operational test of the IAEA Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency, which had entered into force shortly before. The experience reshaped safety protocols for radioactive sources worldwide and forced a global reassessment of the “orphan source” problem — equipment containing radioactive material that falls out of regulatory control without proper decommissioning.
For professionals working with teletherapy and radiotherapy equipment under regulatory oversight, the Goiânia accident remains the starkest reminder that regulatory control must not fail. No response measure, however competent, can replace prevention.
How the Cesium-137 Accident in Goiânia Happened
The Goiânia radiological accident resulted from the convergence of institutional abandonment and human curiosity. The Goiânia Institute of Radiotherapy (IGR) had ceased operations in 1985 and relocated, but a teletherapy unit — a Cesapan F-3000 manufactured by the Zentralinstitut für Kernforschung in Germany — was left behind in the partially demolished former clinic. The sealed radioactive source was not under any radiation protection surveillance.
The equipment head housed the rotating assembly with the sealed source: a stainless steel capsule packed with pressed cesium chloride (CsCl) in the form of compacted salt. The activity at original calibration was 50.9 TBq (1,375 Ci) — an extremely intense source designed for external beam cancer treatment. When two scrap collectors removed the rotating assembly and took it home, they attempted to dismantle the capsule to sell the metal. Breaching the enclosure exposed the CsCl salt to the open environment.
The material had a property that would change the course of events: it glowed an intense blue in the dark, a luminescence phenomenon that captivated everyone who saw it. Fragments of the powder were distributed among family members and acquaintances as a curiosity. Pieces were even sold to junkyards in the neighborhood. Children played with the substance. Contamination grew exponentially over two full weeks before anyone connected the clinical symptoms — nausea, vomiting, skin burns — to the luminescent material.
The IAEA report details the institutional context, the regulatory failures that allowed the source to be abandoned, the physical structure of the teletherapy unit, and a day-by-day chronology. Read the full sequence of events and the failures that made the accident possible.
Discovery and Initial Response Mobilization
The connection between the symptoms and radioactive contamination was established on September 29, 1987 — nearly three weeks after the capsule was breached. The wife of a junkyard owner who had purchased material from the source brought a fragment to Goiânia’s health surveillance office. A physicist measured alarming radiation levels and immediately alerted CNEN.
CNEN dispatched a field team within hours. The first group included radiation protection and dosimetry specialists, plus a physician who had been specifically trained for radiological accident response — a capability developed through a pre-existing IAEA-Brazil technical cooperation program that included expert missions and fellowship training before the accident ever occurred.
The advance team conducted initial radiological triage, identified the main contamination hotspots, and began segregating the most heavily exposed individuals. The task was massive: multiple residences, junkyards, and public locations were contaminated, and the number of potentially affected people grew with every hour as new sites emerged during radiological surveys.
Survey instruments were gathered from every available source: CNEN institutes (IRD, IEN, IPEN), FURNAS, NUCLEBRAS, universities, and foreign aid. The operation ultimately fielded 55 dose rate meters, 23 contamination monitors, and 450 quartz fibre electrometer (QFE) dosimetric pens. The diversity of instruments brought its own challenges — some arrived without calibration certificates or instruction manuals, forcing the establishment of an improvised electronics and calibration laboratory in Goiânia to keep the instrument fleet operational throughout the campaign. Our article on the discovery and initial response covers every step of those critical first hours.
Medical Response to the Accident Victims
The medical component of the response faced unprecedented challenges in Brazil. Patients presented a spectrum ranging from mild skin contamination to potentially lethal acute radiation syndrome. Medical teams had to simultaneously manage radiation-induced skin injuries, severe immunosuppression, opportunistic infections from bone marrow aplasia, and internal cesium-137 contamination — a scenario for which no Brazilian hospital had prior experience.
Initial triage classified patients by exposure level and urgency. The most severe cases were transferred to specialized hospitals. Treatment for patients with significant cesium incorporation included Prussian Blue (ferric ferrocyanide), a chelating agent that binds cesium in the gastrointestinal tract and accelerates its fecal elimination, significantly reducing the biological half-life of the radionuclide. Intensive care for infections — worsened by bone marrow destruction in the most severe cases — and surgical management of radiation skin injuries completed the therapeutic arsenal.
Four people did not survive: two children and two adults who had direct, prolonged contact with the open source. A six-year-old girl who had rubbed the luminescent powder on her body was among the victims. Post-mortem examinations revealed the distribution of cesium-137 across tissues and organs, generating pathological data that contributed to the international medical literature on the incorporation kinetics of this radionuclide in humans. Read the dedicated article on the medical response, including clinical protocols and patient outcomes.
Dosimetry and Cesium-137 Exposure Assessment
Quantifying the radiation dose received by each exposed individual was one of the greatest technical challenges of the accident. Exposure patterns varied enormously — from direct dermal contact with the open source, to inhalation and ingestion of contaminated dust, to prolonged environmental exposure in residences where fragments had been deposited. No single method could capture this complexity.
Internal dosimetry employed whole-body counters to measure retained cesium-137 activity in each patient, combined with urinary and fecal excretion bioassays to estimate total incorporation over time. Compartmental models of cesium kinetics in the body projected committed doses — the dose an individual would continue receiving over years as the material was slowly eliminated.
External dosimetry reconstructed doses from environmental measurements at each person’s residence and workplace, cross-referenced with detailed occupancy pattern information gathered through individual interviews. Cytogenetic analysis, performed in Brazilian and international laboratories, counted chromosomal aberrations (dicentrics and rings) in peripheral blood lymphocytes — a biological dose estimate independent of physical methods that served as cross-validation.
The convergence of all three methods gave credibility to the final estimates and guided critical therapeutic decisions, such as the escalation of Prussian Blue treatment and prioritization of intensive care. The dosimetry article presents each method in depth, with per-patient results.
Environmental Contamination and Decontamination of Goiânia
Decontamination was undoubtedly the most resource-intensive phase of the entire response. About 550 workers participated in field operations in Goiânia, under strict occupational dose controls limited to 1.5 mSv per worker per day.
Scale of contamination
| Category | Count | Details |
|---|---|---|
| Contaminated houses | 85 | Significant contamination detected |
| Evacuated houses | 41 | Above action criteria |
| Demolished houses | 7 | Decontamination not feasible |
| Public places cleaned | 45 | Sidewalks, squares, shops, bars |
| Contaminated vehicles | ~50 | Various types |
| Workers deployed | 550 | In decontamination operations |
Source: The Radiological Accident in Goiânia (IAEA, 1988)
Decontamination techniques
The protocol began by locating a clean external point outside each residence, covering it with plastic sheeting, and removing all movable items for individual monitoring. The decision to decontaminate or discard each item depended on ease of cleaning — except for jewelry and personal items of sentimental value, which received preferential treatment. The report notes the psychological impact: seeing toys, photographs, and personal belongings piled in yards for radiological triage deeply affected both residents and technicians.
Indoors, vacuum cleaners with HEPA filters cleaned all surfaces. Red ceramic floors were treated with acid mixed with Prussian Blue. Roof contamination from atmospheric deposition was washed with pressurized water jets, but this method reduced dose rates by only about 20% — two roofs had to be entirely removed. At the worst contamination focus — the house where the capsule was breached — surface soil dose rates reached 1.5 Sv/h, a lethal exposure in just over two hours. More than 90% of the most contaminated soil was in the surface layer.
Environmental monitoring
| Medium | Sampling | Results |
|---|---|---|
| Groundwater | 30 wells inspected | Maximum 30 Bq/L (disused well); others below 1.5 Bq/L |
| Rainwater | 11 stations (Aeroporto district) | No detection above 150 Bq/L |
| Air | 5 high-volume samplers (58 m³/h) | Peaks in November; otherwise an order of magnitude lower |
| Treated water | Plant and reservoirs upstream | Below minimum detectable (1 Bq/L) |
Source: The Radiological Accident in Goiânia (IAEA, 1988)
The confirmation that treated water and reservoirs consistently remained below detection limits was crucial for maintaining public confidence during the crisis. The dedicated article on environmental contamination covers the full radiological surveys, intervention criteria, and each decontamination step.
Radioactive Waste Management
The accident response generated radioactive waste from day one. A health physics team was assigned on October 1 to manage this material systematically, implementing standardized report forms that tracked each package’s origin, physical form, combustibility, and dose rates.
Classification and packaging
| Classification | Criterion | Legal basis |
|---|---|---|
| Non-radioactive | Activity < 74 kBq/kg (2 nCi/g) | CNEN Resolution 19/85 |
| Low level | Dose rate < 2 mSv/h at package surface | CNEN Resolution 19/85 |
| Intermediate level | Dose rate 2–20 mSv/h at package surface | CNEN Resolution 19/85 |
Source: The Radiological Accident in Goiânia (IAEA, 1988)
Low-level waste was packed in 18-gauge carbon steel drums (40 L, 100 L, and 200 L) and ribbed metal boxes (1.2 m³, 5-tonne maximum load, with zinc chromate and acrylic paint corrosion-resistant surfaces). Intermediate-level waste went into 200 L drums placed inside VBAs — concentric cylindrical packagings with 200 mm reinforced concrete walls, originally manufactured for use at the Angra nuclear power plant.
| Package type | Quantity | Use |
|---|---|---|
| Drums (200 L) | 3,800 | Low and intermediate level waste |
| Metal boxes (1.2 m³) | 1,400 | Low level waste |
| Roll-on-roll-off containers (32 m³) | 10 | Large-volume contaminated paper |
| VBAs (200 mm concrete) | 6 | Intermediate level waste |
Source: The Radiological Accident in Goiânia (IAEA, 1988)
Storage and transport
The temporary storage site occupied a sparsely populated area 20 km from Goiânia and 2.5 km from the city of Abadia de Goiás. Six concrete platforms received 3,500 m³ of waste. Each concrete plate measured 0.15 m thick by 2.75 m × 2.75 m, accommodating 8 boxes or 32 drums in double stacking. The most radioactive packages were placed at the center of each platform to minimize dose rates in access corridors and at the security fence.
Between October 25 and December 19, 1987, 275 truck loads were transported to the site in police-escorted convoys at maximum speeds of 20 km/h in the city and 45 km/h elsewhere. Health physicists accompanied every convoy. One truck left the road and overturned during transport, but without radioactive release — demonstrating that the packaging held up under impact.
The best estimate of total recovered radioactivity, including material at the Marcílio Dias Naval Hospital, was approximately 44 TBq (1,200 Ci), compared to the original source activity of 50.9 TBq (1,375 Ci). Comprehensive environmental monitoring confirmed no significant residual hazard in the urban environment.
International Cooperation and the IAEA’s Role
The Goiânia accident was the first operational test of the IAEA Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency. Brazil informed the Agency shortly after the accident’s discovery and formally requested assistance under the new international instrument.
A critical factor in the quality of the response was the pre-existing IAEA-Brazil technical cooperation program. This program had funded expert missions to Brazil, laboratory construction, and staff training through fellowships — including the training of a Brazilian physician in radiological accident medical response. Without this prior preparation, the learning curve during the first hours would have been far steeper.
International assistance provided experts in medicine, radiation protection, and waste management, along with equipment that complemented national resources. After the crisis was contained, extensive collaborative activities between Brazilian and international experts systematically evaluated the experience. The scientific database generated — covering human dosimetry, urban cesium migration, radionuclide incorporation kinetics, acute radiation syndrome treatment, and large-scale decontamination logistics — fueled joint research projects with universities and international scientific organizations. Our article on lessons and emergency preparedness details every IAEA recommendation and its regulatory impact.
Lessons for Radiation Protection and Emergency Preparedness
The IAEA report concludes with observations and recommendations that remain relevant nearly four decades later. The Goiânia accident exposed systemic vulnerabilities that extend far beyond a single case of negligence and touch on structural issues in radioactive source control worldwide.
The most fundamental failure was regulatory control over disused sealed sources. The teletherapy source was not under CNEN surveillance when the clinic closed. No effective mechanism existed to track orphan sources — medical or industrial equipment containing radioactive material that falls out of use without proper decommissioning. This problem was not unique to Brazil. Orphan sources posed — and continue to pose — a significant global risk, with hundreds of minor incidents recorded in various countries since.
Public communication emerged as another central lesson. During the crisis, rumors, fear, and misinformation threatened to impede field operations. CNEN’s strategy of transparent, open monitoring — including the publication of treated water measurements consistently showing levels below detection — helped preserve public trust in a situation of enormous social tension. Goiânia demonstrated that risk communication is not an add-on to technical operations; it is an essential part of the response.
The Goiânia response proved that well-trained professionals and rapid inter-institutional cooperation can contain a serious radiological disaster. But it also proved — painfully — that prevention is irreplaceable. High-activity sources that go out of service must be safely decommissioned, stored under controlled conditions, or returned to the manufacturer. The accident drove deep revisions in CNEN regulations and directly influenced the development of stricter international standards for radioactive source control throughout their entire lifecycle.
For professionals working with radiotherapy equipment specifications, Goiânia offers a practical and urgent reminder: complete source traceability, from manufacturer to final disposal, is not bureaucracy — it is the barrier that separates safe operation from potential catastrophe. In the dedicated article on accident lessons, we detail every IAEA recommendation and the regulatory changes that followed in Brazil and globally.
