Clinic of Zaragoza radiotherapy accident

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The 1990 Clinic of Zaragoza radiotherapy accident was a radiological accident that occurred from 10 to 20 December 1990, at the Clinic of Zaragoza, in Aragon, Spain.

In the accident, at least 27 patients were injured, and 11 of them died, according to International Atomic Energy Agency (IAEA).[1] All of the injured were cancer patients receiving radiotherapy.[2] On 7 December 1990, a technician performed maintenance on an electron accelerator at the Clinic of Zaragoza. On 10 December, it returned to service after the repairs. On 19 December,[3] the Nuclear Safety Council (CSN) was scheduled to make its annual review of the device, but due to bureaucratic reasons this review was delayed. The CSN found the electron accelerator power was too high. On 20 December 1990, the unit was stopped and was restarted on 8 March 1991.


Affected patients immediately suffered burns on the skin of the irradiated area, as well as inflammation of the internal organs and bone marrow. The first patient died on 16 February 1991, two months after irradiation. Fatalities increased until, on 25 December 1991, the last of a total of 25 patients died. The IAEA established that 11 of the deaths were due to the faulty maintenance.

The accident[edit]

The radiotherapy unit was repaired without following the correct instructions. The unit, in service 14 years at the time of the failure, had a breakdown in the electron beam accelerator control system ("deviator"). Repairs incorrectly increased output power, so patients that should have received therapy at 7 MeV were instead treated at 40 MeV.[4]

See also[edit]


  1. ^ "IAEA Bulletin 413" (PDF). Archived from the original (PDF) on June 8, 2009.
  2. ^ "El accidente del Clínico de Zaragoza, una cadena de fallos humanos única en el mundo, según los expertos". El País (in Spanish). October 12, 1991. Archived from the original on October 10, 2012.
  3. ^ Garriga, Josep; Ortega, Javier (February 23, 1991). "El CSN no controló el aparato radiactivo del Clínico de Zaragoza en un año y medio". El País (in Spanish). Archived from the original on October 10, 2012.
  4. ^ Serrano, Sebastian (February 26, 1991). "Un técnico revisó el acelerador del Clínico de Zaragoza tres días antes del accidente". El País (in Spanish). Archived from the original on October 10, 2012.

Coordinates: 41°38′N 0°54′W / 41.63°N 0.9°W / 41.63; -0.9