From the review of the incident, it is clear that the accident
was due to negligence and a disregard of radiation safety
regulations in many aspects. According to the Thai Act for
Atomic Energy for Peace, medical users must apply to
OAEP for a yearly registration of premises and use of
teletherapy sources as well as for the import or export of
every shipment of radioactive substances. Likewise when
any source is obsolete, the source owner must inform the
OAEP of its intention to discontinue the use of such source
and obtain permission to return it to the original supplier, or
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request to have it disposed of by using the OAEP disposal
facility. If disposal or sale does not occur, the source owner
must get the premises’ registration and source use permit
extended.
In this case, the most serious omission occurred when
the medical users bought a new Co-60 unit, and returned
the obsolete units to the Medical Dealer without notifying
the OAEP. Moreover three obsolete units were kept in
premises under the control of a person who through
ignorance or carelessness moved them to a place easily
accessible to anyone. This action invited theft. The ignorant
victims were those who earned their living in the scrap
trade. They had no knowledge of the trefoil radioactive sign
and could not read the warnings in English. The theft of
such an orphan source brought these people severe injuries
and, in some cases, death.