1. Biological Effects of Ionizing Radiation Deterministic effects
Part No...., Module No....Lesson No
Module title
IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources
Biological Effects of Ionizing Radiation Deterministic effects
Part III: Biological Effects of Ionizing Radiation
Module III.2: Deterministic effects
Lesson III.2.8: Case history – San Salvador accident
Learning objectives: Upon completion of this lesson, the students will be able to:
describe San Salvador accident.
Duration: 0.5 hour
Materials and equipment needed: none
References:
International Atomic Energy Agency, The Radiological Accident in San Salvador, IAEA Report, IAEA, Vienna (1990).
IAEA Regional Train-the-Trainers Workshop Practical Response to a Radiological Emergency, November, Slovenia, Training materials
Case history – San-Salvador accident
Lecture
IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

2. Introduction – Where did the accident occur?
Part No...., Module No....Lesson No
Module title
Introduction – Where did the accident occur?
Accident location: San Salvador (El Salvador)
Facility: industrial irradiation facility
Date: 5 February 1989
Source: Co-60 in a movable source rack
Activity: 0.66 PBq (18 kCi) at the time of the accident
Honduras
Guatemala
Lecture notes:
The accident occurred at an industrial irradiation facility near San Salvador, El Salvador, that was built in 1974 and commissioned in 1975.
El Salvador had been in a state of civil war since 1979.
There was no regulatory control of nor any appropriate infrastructure for radiological protection in El Salvador.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

3. Part No...., Module No....Lesson No
Module title
Content
Where did the accident occur
What happened
Consequences of the accident
Response
Causes of the accident
Lessons learned
Lecture notes:
The following topics are covered in the lesson:
Where did the accident occur
What happened
Consequences of the accident
Response
Causes of the accident
Lessons learned.
Add module code number and lesson title
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

4. Overview - Irradiation facility
Part No...., Module No....Lesson No
Module title
Overview - Irradiation facility
The product packages to be sterilized are loaded into large product boxes and moved by pneumatic cylinders around a centrally located, vertical rectangular source rack
The source rack contains Co-60 source elements in the form of rods contained in ‘source pencils’
Lecture notes:
The process was fairly standard. The products were irradiated in a protected shielded room. safeguards were in place to prevent entry into the room during the operation of the irradiator. Interlocks and alarms made it normally impossible for someone to open the door to the room while the source was unshielded.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

5. Part No...., Module No....Lesson No
Module title
What happened
Sunday 5 February: the source rack becomes stuck in the irradiation position “ON”
The operator bypasses the irradiator’s already degraded safety systems and enters the radiation room, soon followed by two other workers, to free the source rack manually
Lecture notes:
Despite the safety systems in place, workers managed to bypass the interlocks when the source became stuck outside of its shielded position. How this was done was “ingenious” in itself but showed complete disregard for the safe operating procedures.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

6. What happened (Cont’d)
Part No...., Module No....Lesson No
Module title
What happened (Cont’d)
On the following Thursday or Friday, some pencils fell from the upper source module into the pool
Four of the pencils from the top module, an active source pencil and tree dummy pencils, were subsequently found to have fallen into the radiation room; the others had fallen into the pool
Lecture notes:
The accident was further complicated by the fact that the source structural integrity was breached. Some of the highly radioactive elements even fell on the floor of the irradiation room.
Photo
The Cerenkov radiation shows all fourteen source pencils.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

7. Part No...., Module No....Lesson No
Module title
Consequences
Three workers developed acute radiation syndrome
Two of them had their legs and feet amputated
One died six and a half months after the accident
His death is attributed to residual lung damage due to irradiation
Lecture notes:
The workers were exposed to irradiation from Co-60 elements while manipulating the source rack, receiving potentially lethal doses. All three workers began vomiting within few hours and they went one by one to the hospital.
Through the following week, the management of the plant remained unaware of the seriousness of the accident and the facility continued to be operated normally.
The company was aware of the receipt of sick notes for the absent workers. However, these notes stated that the men were suffering from food poisoning. The company remained unaware that the accident on Sunday had caused any radiological injury to workers until contacted by medical staff of the hospital on Wednesday. However the significance of the injuries was then still not appreciated.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

8. Part No...., Module No....Lesson No
Module title
Response
Dose assessment
Worker A 8.1 Gy
Worker B 3.7 Gy
Worker C 2.9 Gy
Medical assessment and treatment
Source recovery in slow time
Lecture notes:
In this example, the actual emergency was over once the workers became exposed, except for the medical implications. The source was confined, and the risk of contamination was nil. There was nothing that prompt emergency response could do to mitigate the consequences. Once recognized, the sources could be retrieved in slow time, taking care to implement all required safety precautions to prevent further severe exposure to other workers.
Hence, the main response was to provide medical treatment for the exposed workers.
Nevertheless, because the accident was not immediately discovered, four additional workers were overexposed. None of the workers had personal dosimeters. Their exposures were discovered only later after cytogenetic tests were made on all workers who might have been exposed as a result of the accident.
The three workers who were primarily exposed received doses of:
Worker A 8.1 Gy
Worker B 3.7 Gy
Worker C 2.9 Gy
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

9. Part No...., Module No....Lesson No
Module title
Causes of the accident
Component failure
The company did not implement measures detailed in notices from supplier designed to upgrade the safety of the facility
The installed safety systems had degenerated or been bypassed over the years
Operator error
Operators trained by the supplier of the irradiators had left at an early stage and subsequent training was only oral and informal
Violation of procedures
There was no regulatory control of radiological protection matters nor any readily available expertise in El Salvador
Lecture notes:
The causes of this accident can be categorized as component failure, human failure and institutional failure.
The component failure stems from the negligence of the user who did not implement required maintenance and changes to the installed safety systems. The fact that it was possible to bypass the interlock system is in itself a design flaw.
The human failure is linked to the disregard by operator of safe operating procedures. The fact that adequate training was not maintained amplified this problem.
Module 5 - Part 2
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

10. Part No...., Module No....Lesson No
Module title
Summary
This lecture presented materials about San Salvador accident
The following conclusion could be made:
Regulatory controls could have prevented this accident
Prompt access to qualified medical resources is a requirements
Arrangements for prompt international assistance can improve the response effectiveness
Comments are welcomed
Let’s summarize the main subjects we did cover in this session. This lecture presented materials about San Salvador accident.
Institutional failure includes failure of the regulatory controls to ensure the ability of the operators to properly operate and maintain the equipment, failure of the operating organization to establish and enforce safety procedures and failure of the operating organization to establish measures to recognize the situation and implement appropriate response measures.
The physical integrity of the irradiation facility, particularly its safety features, was allowed over a long period to degrade significantly and the supplier’s recommendations for upgrading safety were not heeded.
Safety procedures at the facility and training in their observance had deteriorated to the point of inadequacy. Not only did this contribute to the accident, it also meant that the initial exposures went unrecognized, as did the damage to the source rack, which lead to further overexposures.
The management of the facility failed to maintain a corporate awareness of the acute danger inherent in the unauthorized or improper operation of such an irradiation facility.
Production concerns overrode any safety concerns that the sole operator on duty may have had.
The immediate cause of the accident (the jamming and deforming of product boxes which in turn obstructed the descent of the source rack) would have been prevented had earlier recommendations by the supplier been heeded.
Add module code number and lesson title
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources

11. Where to Get More Information
Part No...., Module No....Lesson No
Module title
Where to Get More Information
International Atomic Energy Agency, The Radiological Accident in San Salvador, IAEA Report, IAEA, Vienna (1990)
IAEA Regional Train-the-Trainers Workshop Practical Response to a Radiological Emergency, November, Slovenia, Training materials
Add module code number and lesson title
IAEA Post Graduate Educational Course in Radiation Protection and Safe Use of Radiation Sources