CBRN event in China on Tue 1st December 1992

One piece of a Cobalt 60 source was lost in Xinshou District, Shanxi Province, which caused on Dec. 3, 1992, the death of Mr. Zhan Youchang who picked up the lost Cobalt-60 source. His brother and father also died due to overexposure on December 7 and 10, respectively.
The lost Cocalt 60 source has been found and stored safely.
The actions of medical examination and inspection have been taken in the scope of about 90 people who might have suffered from radioactive exposure. The examination showed that only 5 of them were overexposed. They received appropriate medical treatment.
The cause and process of this incident are under investigation.
According to the INES users' manual - III.3.3 this event is preliminarily rated at level 3.