Criminals may disperse radioactive materials by contaminating drinking water or detonating a "dirty bomb".
A dirty bomb is a weapon that uses conventional explosives to scatter radioactive material over a large area. The force of the blast from a dirty bomb is a greater threat to public health than radiation sickness or long-term health effects resulting from radiation exposure or contamination.
Small amounts of non-destructive radioactive material are used in construction and academic research and are licensed, inspected and controlled by the Canadian Nuclear Safety Commission.
This type of radiation poses little threat to public health, even in the wrong hands. Though exposure to industrial radiation is limited, it is important to recognize the warning symbol for radiation so that you can avoid coming in direct contact with radioactive materials and areas where radioactive material is present.