A supervising person performed dose rate monitoring but he did not “believe” his “old” device that indicated high dose rate. When a day after another survey meter indicated dose rates up to 8 mSv/h the work was stopped. The event was reported to the regulatory body and the regulatory body inspectors monitored the room, found a Co-60 source, estimated its activity to 100 GBq and took appropriate protective measures

As a consequence of the event, the foundryman (not a radiation worker) was irradiated and his personal whole-body effective dose was estimated to 50 – 80 mSv and the extremity dose (to hands) to 0.1 – 10 Sv. As a precaution, a medical examination including blood test was undertaken. The foundryman had no symptoms of deterministic health effects.