Date: 25 June 1990
Location: Shanghai, P.R. China
Type of event: irradiator accident
An accident occurred at an industrial irradiator which used a 23,000-curie cobalt-60 source for sterilization of traditional Chinese medicines. Access to the irradiation room was via a double door which had safety interlocks to prevent enter while the source was unshielded. However, the motor on one door had previously failed, putting the door out of commission, and a power failure disabled the interlock on the second door. One worker additionally violated procedure by turning on lights in the room without turning on electricity of the source system. During this period 7 workers entered the room to arrange product boxes for irradiation, with exposure times up to 40 minutes. None wore personal dosimeters. A metal shroud prevented them from seeing that the source was exposed.
One worker had nausea within 20 minutes, and several were vomiting within 2 hours. Several were hospitalized the following day. Two workers, ages 56 and 53, sustained exposures of 1,200 rad and 1,100 rad, respectively. They were given bone marrow transplants from relatives, but both died, 25 and 90 days after exposure, respectively. A third worker, 53 years old, received a 240 rad dose and recovered from moderate radiation sickness but died of lymphoma 15 years late. Two workers recovered from severe radiation sickness from doses of 520 rad (subject age 24) and 410 rad (age 45). The remaining two workers recovered from moderate radiation sickness, their doses 250 rad (age 20) and 200 rad (age 33).
Consequences: 2 fatalities, 5 injuries.
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Last modified 10 July 2022.
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