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Accidental Disposal of a Co-57 Source

What happened?  

As two Radiation Safety staff were working on opening radioactive materials shipments, one of the technicians was clearing out empty boxes and accidentally took out, and disposed of a box containing a Co-57 (5.55mCi) dose calibrator standard. When the oversight was discovered the Radiation Safety team used a NaI detector and four technicians, to locate the source in the dumpster later that day. The source was fortunately still in the lead pig it was shipped in and no contamination was detected in the dumpster.

What was the cause? 

The root cause for this incident was not double-checking the empty boxes for anything, as well as not separating the empty boxes from the boxes with radioactive material.

How can incidents like this be prevented? 

  • Proper labelling of empty and non-empty radioactive use items.
  • Proper storage of radioactive packages.
  • Do not store any radioactive waste directly next to trash.


  • Deface old or empty boxes with any radiation symbols.
  • Always be sure to scan empty boxes for any surface contamination.
  • In case of a radioactive spill, know your spill and decontamination procedures.
  • Know who to contact in case of a radiological emergency.