The Canadian Nuclear Safety Commission lost an undisclosed amount of cesium-137, a radioactive nuclear substance, before it was discovered in the federal agency’s Centretown office.
The commission said officials were teaching summer students how to locate radioactive material at the 280 Slater St. office.
Some of the material was left behind and had been missing for nearly three weeks before it was found on July 17. Radiation protection staff was called in to remove it.
The agency said the material contained little radioactivity and did not pose a safety risk.
The agency is investigating the incident to prevent any future loss of material.