People worry that terrorists could construct a "dirty bomb" if they ever got their hands on some radioactive material. Apparently it's as easy as finding some Mexican truck driver asleep on the side of the road 🙄
I have read this story several times. It leaves me with more questions than answers. Overall the people in charge were to complacent, to cheap, or were unable to follow established transportation and security procedures. This, sadly, probably occurs all over the world and this shipment is probably the only lost shipment that was made public, but was probably not the only lost shipment.
There have been several examples where hazardous materials have been disposed of improperly due to laziness, complacency, to save money, etc. If an individual or organization really wanted some radioactive material they could likely get their hands on it.